WO2024218132A1

WO2024218132A1 - Reservoir for aerosol-generating system having specific surface chemistry

Info

Publication number: WO2024218132A1
Application number: PCT/EP2024/060386
Authority: WO
Inventors: Jérôme Jean-Yves GIRARD; Laurent Serge LAVANANT; Ping Li; María de los Ángeles LILLO RÓDENAS; María del Carmen ROMÁN MARTÍNEZ; Elena Georgiana TANE
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-04-21
Filing date: 2024-04-17
Publication date: 2024-10-24
Anticipated expiration: 2025-10-21
Also published as: CN121078993A

Abstract

There is described an aerosol-generating substrate reservoir (103) for use in an aerosol-generating system (200). The aerosol-generating system (200) may be a personal aerosol-generating system, such as an electronic vaping system, which is configured to deliver an aerosol to a user. The aerosol-generating substrate reservoir (103) comprises a porous element comprising activated carbon. The porous element has a surface concentration of oxygen (Ototal) when measured using temperature programmed desorption of at least 3 weight percent. An aerosol-generating substrate is sorbed in the porous element. The aerosol-generating substrate may comprise at least one of glycerol, nicotine, water, and an acid. There is also described an aerosol-generating system (200) comprising the aerosol-generating substrate reservoir (103), and a method of preparing the aerosol-generating substrate reservoir.

Description

RESERVOIR FOR AEROSOL-GENERATING SYSTEM HAVING SPECIFIC SURFACE CHEMISTRY

There is provided a reservoir for an aerosol-generating system. In particular, there is provided an aerosol-generating substrate reservoir for use in an aerosol-generating system, the aerosol-generating substrate reservoir comprising a porous element. The porous element comprises activated carbon. There is also provided an aerosol-generating system comprising the aerosol-generating substrate reservoir, and a method of forming the aerosol-generating substrate reservoir.

Aerosol-generating systems for delivering an aerosol to a user are known. Some known aerosol-generating systems are configured to heat an aerosol-generating substrate. Such aerosol-generating systems may comprise a reservoir of aerosol-generating substrate in fluid communication with a heater.

The heater may be an electrical resistive heater. Where this is the case, the heater may comprise a coil of electrically conductive wire that is wound around an elongate wick, which transports aerosol-generating substrate from the reservoir to the coil of wire. In use, an electric current may be passed through the coil of wire to heat the aerosol-generating substrate to generate an aerosol.

In other known handheld electrically operated aerosol-generating systems the heater comprises a fluid permeable heating element comprising an electrically conductive mesh that is in contact with a transport material, which conveys aerosol-generating substrate from the reservoir to the electrically conductive mesh. In use, an electric current may be passed through the electrically conductive mesh to heat the nicotine formulation to generate an aerosol.

Such known handheld electrically operated aerosol-generating systems may comprise an aerosol-generating cartridge comprising the electrical resistive heater and the aerosolgenerating substrate reservoir. A cartridge containing an electrical resistive heater and an aerosol-generating substrate reservoir is sometimes referred to as a “cartomiser”. The cartridge typically also comprises a mouthpiece portion that a user draws on, in use, in order to inhale the generated aerosol.

The aerosol-generating cartridge may cooperate with an aerosol-generating device. The aerosol-generating device may comprise control circuitry and a power supply for supplying power to the electrical resistive heater of the aerosol-generating cartridge.

In other known aerosol-generating systems, an aerosol-generating article comprises an aerosol-generating substrate. The aerosol-generating article does not include an electrically operated heating element. Instead, the aerosol-generating article is intended to be used with an aerosol-generating device, the aerosol-generating device may comprise control circuitry, a power supply, and an electrical resistive heater which is arranged to heat the aerosol-generating substrate when the aerosol-generating article is used with the aerosolgenerating device. For example, the aerosol-generating device may comprise a heating chamber including the electrical resistive heater. When the aerosol-generating article is received in the heating chamber, the electrical resistance heater is arranged to heat the aerosol-generating substrate to generate an aerosol for inhalation by a user.

In further know aerosol-generating systems, an aerosol-generating article comprises an aerosol-generating substrate and a non-electrical heating means. For example, the aerosol-generating article may comprise a combustible heating element, for example a combustible carbonaceous heating element, in close proximity to the aerosol-generating substrate. In use, a user may ignite the combustible heating element. The heat generated from the combustible heating element is transferred to the aerosol-generating substrate generating an aerosol for inhalation by a user.

In each of these examples, the aerosol-generating substrate may be retained in an aerosol-generating substrate reservoir. Known aerosol-generating substrate reservoirs may comprise hollow containers configured to retain aerosol-generating substrate. Some known aerosol-generating substrate reservoirs may comprise porous elements with an aerosolgenerating substrate sorbed in the porous element.

Where the aerosol-generating substrate reservoir comprises a porous element with an aerosol-generating substrate sorbed in the porous element, when the porous element is heated, the aerosol-generating substrate is desorbed from the porous element to generate an aerosol for inhalation by a user.

It has been found that the rate and extent to which aerosol-generating substrate is desorbed from a porous element as it is heated may vary depending on the nature of the porous element. The rate and extent to which aerosol-generating substrate is desorbed from a porous element as it is heated can influence the user experience of the aerosol-generating system.

As a result, there is a need to carefully control the rate and extent to which aerosolgenerating substrate is desorbed from a porous element as it is heated during use of an aerosol-generating system.

According to a first aspect of the present disclosure, there is provided an aerosolgenerating substrate reservoir for use in an aerosol-generating system. The aerosolgenerating substrate reservoir may comprise a porous element. The porous element may comprise activated carbon. The porous element may have a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent. An aerosol-generating substrate may be sorbed in the porous element.

According to a first aspect of the present invention, there is provided an aerosolgenerating substrate reservoir for use in an aerosol-generating system. The aerosolgenerating substrate reservoir comprises a porous element. The porous element comprises activated carbon. The porous element has a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent. An aerosolgenerating substrate is sorbed in the porous element.

The inventors of the present invention have identified that a porous element according to the first aspect of the invention exhibits predictable and advantageous desorption properties during use of an aerosol-generating system including the porous element. As described in more detail below, the inventors have identified that the provision of a porous element formed from activated carbon and having a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent advantageously results in a single desorption peak during the use of the aerosol-generating system. In this way, the user experience is more consistent. This is in contrast to aerosol-generating substrate reservoirs not according to the present invention which may exhibit multiple desorption peaks resulting in inconsistent and fluctuating aerosol delivery during the use of the aerosolgenerating system. This degrades the user experience and is therefore undesirable.

In addition, the inventors of the present invention have identified that a porous element formed from activated carbon and having a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent may be advantageously able to retain a sufficient volume of aerosol-generating substrate per gram of porous element. The porous element according to the present invention may also be able to retain the aerosol-generating substrate such that leakage of aerosol-generating substrate out of the aerosol-generating system is reduced or prevented. The inventors have identified that the porous element comprising activated carbon is able to sorb aerosol-generating substrate by capillary action which draws the aerosol-generating substrate into the pores of the porous element.

The porous element may have an aerosol-generating substrate loading capacity. For example, the porous element may have an aerosol-generating substrate loading capacity of at least 0.5 grams per gram of porous element, preferably at least 0.8 grams per gram of porous element.

The porous element may have an aerosol-generating substrate loading capacity of no more than 1 .5 grams per gram of porous element, preferably no more than 1 .2 grams per gram of porous element. The porous element may have an aerosol-generating substrate loading capacity of about 1 gram per gram of porous element.

While the porous element according to the present invention is able to securely retain aerosol-generating substrate, it is also able to release and desorb the aerosol-generating substrate at relatively low temperatures, e.g. below 300 degrees Celsius. This is advantageous since certain components of typical aerosol-generating substrates, such as glycerine, may begin to decompose at temperatures above 300 degrees Celsius. As a result, the relatively low temperature of desorption from the porous element may advantageously prevent the generation of undesirable thermal decomposition products.

Furthermore, the use of activated carbon may be further advantageous since the activated carbon may remain inert under the operating temperature of the aerosol-generating system. This may prevent the generation of undesirable thermal decomposition products from the porous element and may allow the aerosol-generating substrate reservoir to be reused.

As used herein with reference to the present invention, the term “aerosol-generating system” refers to a device or a combination several devices which cooperate to generate an aerosol for delivery to a user by heating an aerosol-generating substrate.

As used herein with reference to the present invention, the term “aerosol” refers to a dispersion of solid particles, or liquid droplets, or a combination of solid particles and liquid droplets, in a gas. The aerosol may be visible or invisible. The aerosol may include vapours of substances that are ordinarily liquid or solid at room temperature as well as solid particles, or liquid droplets, or a combination of solid particles and liquid droplets.

As used herein with reference to the present invention, the term “aerosol-generating substrate reservoir” refers to a portion of an aerosol-generating system which is configured to retain a portion of aerosol-generating substrate before it is heated to generate an aerosol.

As used herein with reference to the present invention, the term “aerosol-generating substrate” refers to a substrate comprising aerosol-generating material that is capable of releasing upon heating volatile compounds that can generate an aerosol. The aerosolgenerating substrate may be a liquid aerosol-generating substrate. The aerosol-generating substrate may be a gel aerosol-generating substrate.

As used herein with reference to the present invention, the term “gel” is used to describe a substantially dilute cross-linked material, which exhibits no flow in the steady state.

As used herein with reference to the present invention, the term “porous element” refers to a component which has a plurality of pores, at least some of which are interconnected. The porous element is configured to contain an aerosol-generating substrate within the plurality of pores. The porous element may comprise a porous material. The porous element comprises activated carbon. The porous element may consist only of activated carbon.

As used herein with reference to the present invention, the term “activated carbon” refers to a form of carbon which is highly porous over a broad range of pore sizes, from visible cracks and crevices to cracks and crevices of molecular dimensions resulting in very high internal surface area making it ideal for adsorption uses. Activated carbon is suitably defined by ASTM D2652-11 (Reapproved 2020) Standard Terminology Relating to Activated Carbon as “a family of carbonaceous substances manufactured by processes that develop adsorptive properties”. Activation is suitably defined by ASTM D2652-11 (Reapproved 2020) as “any process whereby a substance is treated to develop adsorptive properties”. Activated carbon may be formed by the pyrolysis of organic materials.

As used herein with reference to the present invention, the term “sorb” refers to the process by which the porous element takes in and retains an aerosol-generating substrate. The sorption may include one or more of adsorption and absorption. As described above, the sorption may comprise drawing the aerosol-generating substrate into the pores of the porous element by capillary action.

The aerosol-generating substrate reservoir may comprise other components. The aerosol-generating substrate reservoir may consist only of the porous element sorbed with aerosol-generating substrate.

The surface concentration of oxygen (Ototai) is the total weight percentage of surface oxygen as determined by temperature-programmed desorption (TPD) carried out using a differential scanning calirometer-thermogravimetric analyser (DSC-TGA TA, Simultaneous SDT 2960) coupled to a mass spectrometer (Balzers, OmniStar). The surface concentration of oxygen (Ototai) is related to the evolution of oxygen-containing species during the TPD experiment. These species may include CO2 and CO.

The inventors have identified that the provision of a porous element with a surface concentration of oxygen (Ototai) of at least 3 percent by weight may improve the desorption properties of the porous element. The surface concentration of oxygen is a feature of the activated carbon porous element which may be tailored during the processing of the porous element.

For example, the porous element may have a surface concentration of oxygen (Ototai) of at least 4 percent, at least 5 percent, or at least 6 percent by weight when measured using temperature-programmed desorption (TPD).

The porous element may have a standard BET surface area of at least 100 metres squared per gram. The standard BET surface area of the porous element is determined using N2 isotherms which are generated by adsorption of N2 at -196 degrees Celsius and 0 degrees Celsius using ASAP 2020 from Micromeritics and Autosorb-6B from Quantachrome equipment. The samples are then outgassed at 250 degrees Celsius for 4 hours. The N2 adsorption data may then be used to calculate the apparent BET surface area (SBET) by application of the BET equation.

The porous element may have a standard BET surface area of at least 150 metres squared per gram, at least 200 metres squared per gram, or at least 250 metres squared per gram.

The porous element may have a standard BET surface area of no more than 600 metres squared per gram.

The porous element may have a standard BET surface area of no more than 550 metres squared per gram, no more than 500 metres squared per gram, or more than 450 metres squared per gram.

For example, the porous element may have a standard BET surface area of between 150 metres squared per gram and 550 metres squared per gram, between 200 metres squared per gram and 500 metres squared per gram, or between 250 metres squared per gram and 450 metres squared per gram.

The porous element may have any pore volume. For example, the porous element may have a pore volume measured using adsorption isotherm of carbon dioxide VDR (CO2) of at least 0.05 cubic centimetres per gram. To generate the adsorption isotherm of carbon dioxide, CO2 is sorbed on the sample at -196 degrees Celsius and 0 degrees Celsius using ASAP 2020 from Micromeritics and Autosorb-6B from Quantachrome equipment. The samples are then outgassed at 250 degrees Celsius for 4 hours. The CO2 adsorption data may then be used to calculate the VDR (CO2) by application of the Dubinin-Radushkevich equation.

For example, the porous element may have a pore volume measured using adsorption isotherm of carbon dioxide DR (CO2) of at least 0.1 cubic centimetres per gram, at least 0.15 cubic centimetres per gram, or at least 0.2 cubic centimetres per gram.

The porous element may have a pore volume measured using adsorption isotherm of carbon dioxide VDR (CO2) of no more than 0.35 cubic centimetres per gram.

For example, porous element may have a pore volume measured using adsorption isotherm of carbon dioxide VDR (CO2) of no more than 0.3 cubic centimetres per gram, or no more than 0.25 cubic centimetres per gram.

The porous element may have a pore volume measured using adsorption isotherm of carbon dioxide VDR (CO2) of between 0.05 cubic centimetres per gram and 0.35 cubic centimetres per gram, between 0.1 cubic centimetres per gram and 0.3 cubic centimetres per gram, or between 0.15 cubic centimetres per gram and 0.25 cubic centimetres per gram.

The porous element may have a pore volume measured using adsorption isotherm of carbon dioxide VDR (CO2) of between 0.1 cubic centimetres per gram and 0.25 cubic centimetres per gram.

The porous element may have a pore volume measured using adsorption isotherm of nitrogen VDR (N2) of at least 0.05 cubic centimetres per gram. To generate the adsorption isotherm of nitrogen, N2 is sorbed on the sample at -196 degrees Celsius and 0 degrees Celsius using ASAP 2020 from Micromeritics and Autosorb-6B from Quantachrome equipment. The samples are then outgassed at 250 degrees Celsius for 4 hours. The N2 adsorption data may then be used to calculate the DR (N2) by application of the Dubinin- Radushkevich equation.

For example, the porous element may have a pore volume measured using adsorption isotherm of nitrogen VDR (N2) of at least 0.1 cubic centimetres per gram, at least 0.15 cubic centimetres per gram, or at least 0.2 cubic centimetres per gram.

The porous element may have a pore volume measured using adsorption isotherm of nitrogen VDR (N2) of no more than 0.35 cubic centimetres per gram.

For example, porous element may have a pore volume measured using adsorption isotherm of nitrogen VDR (N2) of no more than 0.3 cubic centimetres per gram, or no more than 0.25 cubic centimetres per gram.

The porous element may have a pore volume measured using adsorption isotherm of nitrogen VDR (N2) of between 0.05 cubic centimetres per gram and 0.35 cubic centimetres per gram, between 0.1 cubic centimetres per gram and 0.3 cubic centimetres per gram, or between 0.15 cubic centimetres per gram and 0.25 cubic centimetres per gram.

The porous element may have a pore volume measured using adsorption isotherm of nitrogen VDR (N2) of between 0.1 cubic centimetres per gram and 0.25 cubic centimetres per gram.

The porous element may have a pore volume measured using V_meso (N2) of at least 0.01 cubic centimetres per gram. The pore volume assessment using V_meso (N2) is used to provide an indication of the volume of pores having a diameter of between about 2 nanometres and 7.5 nanometres. V_meso (N2) may be calculated as the difference between the volume of N2 sorbed as a liquid at P/P0 = 0.7 and P/P0 = 0.2. “P” corresponds to the partial vapour pressure of adsorbate gas in equilibrium and “P0” corresponds to the saturated vapour pressure of adsorbate gas.

For example, the porous element may have a pore volume measured using V_meso (N2) of at least 0.02 cubic centimetres per gram. The porous element may have a pore volume measured using V_meso (N2) of no more than 0.15 cubic centimetres per gram. For example, the porous element may have a pore volume measured using V_meso (N2) of at least 0.08 cubic centimetres per gram.

The porous element may have a pore volume measured using V_meso (N2) of between 0.01 cubic centimetres per gram and 0.15 cubic centimetres per gram, or between 0.02 cubic centimetres per gram and 0.08 cubic centimetres per gram.

The porous element may have a pore volume measured using V_meso (Hg) of at least 0.001 cubic centimetres per gram. The pore volume assessment using V_meso (Hg) is used to provide an indication of the volume of pores having a diameter between 7.5 nanometres and 50 nanometres. Hg intrusion porosimetry may be used to determine the pore volume. Hg porosimetry data may be obtained using a Poremaster-60 GT from Quantachrome Instruments.

For example, the porous element may have a pore volume measured using V_meso (Hg) of at least 0.005 cubic centimetres per gram.

The porous element may have a pore volume measured using V_meso (Hg) of no more than 0.1 cubic centimetres per gram. For example, the porous element may have a pore volume measured using V_meso (Hg) of at least 0.05 cubic centimetres per gram.

The porous element may have a pore volume measured using V_meso (Hg) of between 0.001 cubic centimetres per gram and 0.1 cubic centimetres per gram, or between 0.005 cubic centimetres per gram and 0.05 cubic centimetres per gram.

The porous element may have a total mesopore volume (VT_meso) of at least 0.01 cubic centimetres per gram.

As used herein with reference to the present invention, the term “mesopore” refers to pores of the porous element having a pore diameter of between 2 nanometres and 50 nanometres. The total mesopore volume is the sum of the volumes measured using V_meso (N₂) and Vmeso (Hg). In other words, VT_meso = V_meso (N₂) + V_meso (Hg).

The porous element may have a total mesopore volume (VTmeso) of at least 0.02 cubic centimetres per gram.

The porous element may have a total mesopore volume (VTmeso) of no more than 1 cubic centimetre per gram. For example, the porous element may have a total mesopore volume (VTmeso) of no more than 0.1 cubic centimetres per gram.

The porous element may have a total mesopore volume (VTmeso) of between 0.01 cubic centimetres per gram and 1 cubic centimetre per gram, or between 0.02 cubic centimetres per gram and 0.1 cubic centimetres per gram.

The porous element may have a total macropore volume (V_macro) of at least 0.1 cubic centimetres per gram. The pore volume assessment using V_macro is used to provide an indication of the volume of pores having a diameter greater than 50 nanometres. Hg intrusion porosimetry may be used to determine the pore volume. Hg porosimetry data may be obtained using a Poremaster-60 GT from Quantachrome Instruments.

As used herein with reference to the present invention, the term “macropore” refers to pores of the porous element having a pore diameter of greater than 50 nanometres.

The porous element may have a total mesopore volume (V_macro) of at least 0.5 cubic centimetres per gram.

The porous element may have a total mesopore volume (V_macro) of no more than 5 cubic centimetre per gram. For example, the porous element may have a total mesopore volume (V_macro) of no more than 4 cubic centimetres per gram.

The porous element may have a total mesopore volume (V_macro) of between 0.1 cubic centimetres per gram and 5 cubic centimetres per gram, or between 0.5 cubic centimetres per gram and 4 cubic centimetres per gram.

The porous element may have a total pore volume (VT) of at least 0.05 cubic centimetres per gram.

The total pore volume (VT) refers to the sum of the pore volumes of all of the pores in the porous element per unit mass. The total pore volume (VT) is calculated as the sum of the volumes using V_DR (N₂), VT_meSo, and V_macro. In other words, VT = V_DR (N₂) + VT_meSo + V_macro.

The porous element may have a total pore volume (VT) of at least 1 cubic centimetre per gram.

The porous element may have a total pore volume (VT) of no more than 3 cubic centimetres per gram. For example, the porous element may have a total pore volume (VT) of no more than 2 cubic centimetres per gram.

The porous element may have a total pore volume (VT) of between 0.05 cubic centimetres per gram and 3 cubic centimetres per gram, or between 1 cubic centimetre per gram and 2 cubic centimetres per gram.

The porous element may have a surface concentration of oxygen (Otot_ai) of no more than 20 percent when measured using temperature-programmed desorption (TPD).

For example, the porous element may have a surface concentration of oxygen (Otot_ai) of no more than 18 percent, no more than 14 percent, or no more than 10 percent by weight when measured using temperature-programmed desorption (TPD).

For example, the porous element may have a surface concentration of oxygen (Otot_ai) of between 3 percent and 20 percent by weight, between 4 percent and 18 percent by weight, between 5 percent and 14 percent by weight, between 6 percent and 10 percent by weight when measured using temperature-programmed desorption (TPD). The porous element may have a surface concentration of oxygen (Ototai) of between 8 percent and 17 percent by weight when measured using temperature-programmed desorption (TPD).

The total amount of CO2 and CO evolved from the porous element during temperatureprogrammed desorption (TPD) may be at least 1500 micromoles per gram.

The total amount of CO2 and CO evolved from the porous element during temperatureprogrammed desorption (TPD) corresponds to the sum of the amount of CO2 evolved and the amount to CO evolved during a temperature-programmed desorption (TPD) test carried out using a differential scanning calirometer-thermogravimetric analyser (DSC-TGA TA, Simultaneous SDT 2960) coupled to a mass spectrometer (Balzers, OmniStar).

The inventors have identified that the total amount of CO2 and CO evolved provides an indication of the surface oxygen concentration of the porous element. The higher the total amount of CO2 and CO evolved during a TPD test, the higher the surface oxygen concentration of the porous element. As a result, it has been found that porous elements which evolve at least 1500 micromoles per gram of CO2 and CO during a TPD test advantageously result in a single desorption peak during the use of the aerosol-generating system. In this way, the user experience is more consistent.

The total amount of CO2 and CO evolved from the porous element during temperatureprogrammed desorption (TPD) may be at least 2000 micromoles per gram or at least 2500 micromoles per gram.

The total amount of CO2 and CO evolved from the porous element during temperatureprogrammed desorption (TPD) may be no more than 7000 micromoles per gram or no more than 6000 micromoles per gram.

The ratio of CO2 to CO evolved from the porous element during temperatureprogrammed desorption (TPD) may be at least 0.2.

The inventors have identified that the CO2/CO ratio is an important surface chemistry parameter. During a temperature-programmed desorption (TPD) test, thermal temperature degradation of surface oxygen on the activated carbon porous element leads to the evolution of CO2 and CO gas. CO2 is typically evolved by the decomposition of functional groups which are acidic in character. CO is typically evolved by the decomposition of functional groups which are basic in character. Accordingly, a CO2/CO ratio of about 1 indicates a neutral surface chemistry.

The ratio of CO2 to CO evolved from the porous element during temperatureprogrammed desorption (TPD) may be at least 0.4.

The ratio of CO2 to CO evolved from the porous element during temperatureprogrammed desorption (TPD) may be no more than 1.5. For example, the ratio of CO2 to CO evolved from the porous element during temperature-programmed desorption (TPD) may be no more than 1.2.

The ratio of CO2 to CO evolved from the porous element during temperatureprogrammed desorption (TPD) may be between 0.2 and 1.5, or between 0.4 and 1.2.

The ratio of CO2 to CO evolved from the porous element during temperatureprogrammed desorption (TPD) may be about 1 .

As described above, the provision of an aerosol-generating substrate reservoir comprising a porous element having the parameters of the present invention may advantageously provide a single desorption peak during the use of the aerosol-generating system.

The porous element may exhibit a single derivative TG (DTG) peak. The single derivative TG peak is the differential of the thermogravimetric (TG) curve.

The single derivative TG (DTG) peak may be over 160 degrees Celsius. For example, the single derivative TG (DTG) peak may be over 180 degrees Celsius, over 200 degrees Celsius, or over 220 degrees Celsius.

The single derivative TG (DTG) peak may be no higher than 300 degrees Celsius. For example, the single derivative TG (DTG) peak may be no higher than 280 degrees Celsius, no higher than 260 degrees Celsius, or no higher than 240 degrees Celsius.

The single derivative TG (DTG) peak may be between 160 degrees Celsius and 300 degrees Celsius, between 180 degrees Celsius and 280 degrees Celsius, between 200 degrees Celsius and 260 degrees Celsius, or between 220 degrees Celsius and 240 degrees Celsius.

The single derivative TG (DTG) peak may be between 160 degrees Celsius and 230 degrees Celsius. The single derivative TG (DTG) peak may be about 230 degrees Celsius.

The aerosol-generating substrate may be a liquid aerosol-generating substrate. The aerosol-generating substrate may comprise nicotine.

As used herein with reference to the present invention, the term “nicotine” is used to describe nicotine, a nicotine base or a nicotine salt.

The aerosol-generating substrate may be a liquid nicotine formulation.

As used herein with reference to the present invention, the term “liquid nicotine formulation” describes a liquid formulation comprising nicotine.

The aerosol-generating substrate may comprise natural nicotine.

The aerosol-generating substrate may comprise synthetic nicotine.

The aerosol-generating substrate may have a nicotine content of greater than or equal to 0.5 percent by weight, greater than or equal to 1 percent by weight, or greater than or equal to 1 .5 percent by weight. The aerosol-generating substrate may have a nicotine content of less than or equal to 10 percent by weight, less than or equal to 5 percent by weight, or less than or equal to 3 percent by weight.

The aerosol-generating substrate may have a nicotine content of between 0.5 percent by weight and 10 percent by weight. For example, the first aerosol-generating substrate may have a nicotine content of between 0.5 percent by weight and 5 percent by weight or between 0.5 percent by weight and 3 percent by weight.

The aerosol-generating substrate may have a nicotine content of between 1 percent by weight and 10 percent by weight. For example, the aerosol-generating substrate may have a nicotine content of between 1 percent by weight and 5 percent by weight or between 1 percent by weight and 3 percent by weight.

The aerosol-generating substrate may have a nicotine content of between 1.5 percent by weight and 10 percent by weight. For example, the aerosol-generating substrate may have a nicotine content of between 1 .5 percent by weight and 5 percent by weight or between 1 .5 percent by weight and 3 percent by weight.

For example, the aerosol-generating substrate may have a nicotine content of 2 percent by weight.

Advantageously, the aerosol-generating substrate may comprise an aerosol former.

Advantageously, the aerosol-generating substrate may comprise nicotine and an aerosol former.

The aerosol former may be any suitable known compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol. The aerosol former may be substantially resistant to thermal degradation at temperatures typically reached during use of an aerosol-generating system according to the second aspect of the invention.

Examples of suitable aerosol formers include, but are not limited to: polyhydric alcohols such as, for example, triethylene glycol, 1 ,3-butanediol, propylene glycol and glycerine; esters of polyhydric alcohols such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Advantageously, the aerosol former may comprise one or more polyhydric alcohols.

More advantageously, the aerosol former comprises one or more polyhydric alcohols selected from the group consisting of propylene glycol, triethylene glycol, 1 ,3-butanediol and glycerine.

The aerosol former may comprise one or both of glycerine and propylene glycol. The aerosol former may consist of glycerine. The aerosol former may consist of propylene glycol. The aerosol former may consist of a combination of glycerine and propylene glycol. The aerosol-generating substrate may comprise glycerine.

The aerosol-generating substrate may comprise water.

The aerosol-generating substrate glycerine and water. Where the aerosol-generating substrate comprises both glycerine and water, the ratio by weight of water to glycerine may be at least 0.25. For example, the ratio by weight of water to glycerine may be at least 0.5, or at least 0.75.

The ratio by weight of water to glycerine may be no more than 2. For example, the ratio by weight of water to glycerine may be no more than 1 .75, or no more than 1 .5.

The ratio by weight of water to glycerine may be between 0.25 and 2, between 0.5 and 1 .75, or between 0.75 and 1.5. The ratio by weight of water to glycerine may be about 1.

The aerosol-generating substrate may comprise an acid. The aerosol-generating substrate may comprise a carboxylic acid. For example, the aerosol-generating substrate may comprise at least one of lactic acid, acetic acid, benzoic acid, citric acid, fumaric acid, maleic acid, malic acid, and succinic acid. Preferably, the aerosol-generating substrate comprises at least one of lactic acid and benzoic acid.

The aerosol-generating substrate may comprise one or more natural flavourants.

The aerosol-generating substrate may comprise one or more synthetic flavourants.

The aerosol-generating substrate may comprise any suitable flavourant. Suitable flavourants include, but are not limited to: menthol; peppermint oil; gamma octalactone; vanillin; ethyl vanillin; methyl salicylate; linalool; bergamot oil; geranium oil; ginger oil; and lemon oil. For example, the aerosol-generating substrate may comprise menthol. The aerosol-generating substrate may have a flavourant content of at least 1 percent by weight. The aerosol-generating substrate may have a flavourant content of no more than 30 percent by weight.

The porous element comprises activated carbon. The activated carbon may be provided in any form.

The porous element may comprise powdered activated carbon. The powdered activated carbon may have a D50 particle diameter of between 1 micrometre and 150 micrometres. The provision of a powdered activate carbon may be advantageous since it provides a high surface area to sorb the aerosol-generating substrate.

Where the porous element comprises powdered activated carbon, the porous element may comprise between about 1 ,000 and about 25,000 powder particles of activated carbon. The particles of activated carbon may have any mass. For example the individual particles of activated carbon may have a mass of between 50 milligrams and 200 milligrams. The porous element may comprise fibres of activated carbon. The fibres of activated carbon may have a D50 fibre length of between 25 micrometres and 50 micrometres.

Where the porous element comprises fibres of activated carbon, the porous element may comprise between about 3,500 and about 8,500 fibres of activated carbon.

The porous element may comprise granules of activated carbon. The granules of activated carbon may have a D50 granule diameter of between 150 micrometres and 800 micrometres.

Where the porous element comprises granules of activated carbon, the porous element may comprise between about 200 and about 1 ,500 granules of activated carbon.

The porous element may comprise pellets of activated carbon. The pellets of activated carbon may have a D50 pellet diameter of at least 0.2 millimetres, at least 0.8 millimetres, or at least 1 millimetre. The pellets of activated carbon may have a D50 pellet diameter of no more than 3 millimetres, no more than 2 millimetres, or no more than 1.2 millimetres.

The pellets of activated carbon may have a D50 pellet diameter of between 0.2 millimetres and 2 millimetres, between 1 millimetre and 3 millimetres, or preferably between 0.8 millimetres and 1.2 millimetres.

Where the porous element comprises pellets of activated carbon, the porous element may comprise between about 50 and about 200 pellets of activated carbon.

The provision of a porous element comprising activated carbon in the form of a powder, fibres, granules, or pellets may advantageously allow the porous element to conform to the shape of the space in which it is provided in the aerosol-generating article. This may advantageously easily maximise the amount of porous element provided in the aerosolgenerating substrate reservoir.

Where the porous element comprises activated carbon in the form of a powder, fibres, granules, or pellets, the aerosol-generating substrate may further comprise a container for retaining the porous element. The container may comprise a pouch containing the porous element. The container may have any shape. The container may have a non-cylindrical shape.

The container may define a cavity for receiving the porous element. The container may comprise a frame defining a cavity for receiving the porous element.

The container may comprise at least one air inlet. The container may comprise at least one aerosol outlet. The container may comprise both at least one air inlet and at least one aerosol outlet. Alternatively or in addition, the container may be formed from a porous material. This may advantageously allow air to enter the container and allow aerosol to leave the container during use. The container may be formed from a flexible material. This may allow the container to deform and conform to the shape of the space in which is it provided. This may advantageously allow the container to remain in contact or close proximity to a heater of an aerosol-generating device to be used with the aerosol-generating article throughout the use of the aerosol-generating article. This may be particularly effective where the volume of the porous element remains constant during use.

The container may comprise a cellulosic material. The container may be a pouch of porous, cellulosic material.

The aerosol-generating substrate reservoir may further combine tobacco. The tobacco may be provided as a flavourant. The tobacco may be any tobacco material. The tobacco material may comprise homogenised plant material.

As used herein with reference to the present invention, the term “homogenised plant material” encompasses any plant material formed by the agglomeration of particles of plant. For example, sheets or webs of homogenised tobacco material for the aerosol-generating substrates of the present invention may be formed by agglomerating particles of tobacco material obtained by pulverising, grinding or comminuting plant material and optionally one or more of tobacco leaf lamina and tobacco leaf stems. The homogenised plant material may be produced by casting, extrusion, paper making processes or other any other suitable processes known in the art.

The homogenised plant material may be in the form of a plurality of pellets or granules.

The homogenised plant material may be in the form of a plurality of strands, strips or shreds.

Where the porous element comprises activated carbon in the form of a powder, fibres, granules, or pellets, the aerosol-generating substrate reservoir may further comprise tobacco material in the form of pellets, granules, strands, strips or shreds. In this way, the activated carbon may be readily combined and mixed with the tobacco to advantageously form a homogenous aerosol-generating substrate reservoir.

The porous element may comprise a monolithic portion of activated carbon. The monolithic portion of activated carbon may be shaped to conform to the space in which it is provided in the aerosol-generating article or in the aerosol-generating substrate reservoir. For example, the porous element may comprise a rod or cylinder of activated carbon. The monolithic portion of activated carbon may be formed by a shaping a portion of organic material to the desired form, and then carbonizing and activating the shaped portion of organic material.

Where the porous element comprises a monolithic portion of activated carbon, the porous element may comprise only a single monolithic portion of activated carbon. The porous element comprising activated carbon may be formed by any means which would be familiar to those skilled in the art. The activated carbon may be formed by carbonisation of a carbon precursor.

The carbon precursor may comprise a natural material such as biomass feedstock. Examples of activated carbon biomass feedstock include coconut shell, cassava peel, or wood. The carbon precursor may comprise a synthetic material. The synthetic material may comprise a polymeric carbon precursor. Advantageously, the activated carbon is derived from a synthetic polymer feedstock.

The carbon precursor may be carbonised at a temperature of between 850 degrees Celsius and 900 degrees Celsius for 2 hours.

The carbon may be activated by heating the carbon to between 800 degrees Celsius and 850 degrees Celsius for between 1 and 30 hours in an atmosphere containing CO2. The rate of heating may be at 10 degrees Celsius per minute. The CO2 may be passed over the carbon at a rate of 80 millimetres per minute.

The carbon may be activated by heating the carbon to between 700 degrees Celsius and 850 degrees Celsius for between 1 and 3 hours in an atmosphere containing H2O. The rate of heating may be at 10 degrees Celsius per minute. The H2O may be passed over the carbon at a rate of 200 millimetres per minute.

The aerosol-generating substrate reservoir may consist of a porous element comprising activated carbon, the porous element having a standard BET surface area of between 100 metres squared per gram and 600 metres squared per gram, and an aerosolgenerating substrate sorbed in the porous element.

The aerosol-generating substrate reservoir may further comprise a filtration material.

The filtration material may be any filtration material. The filtration material may comprise a planar material such as a sheet-like material. The sheet-like filtration material may comprise a crimped sheet. The sheet-like filtration material may comprise a gathered sheet. The filtration material may comprise a fibrous material.

The filtration material may comprise at least one of cellulose acetate tow, crimped viscose sheets, paper sheets, or cellulose non-woven material.

Preferably, the filtration material should be thermally stable at the temperatures at which typical aerosol-generating substrates need to be heated in order to generate an aerosol.

As used herein with reference to the present invention, the terms “thermally stable” and “heat resistant” denotes a material that will not substantially thermally degrade or decompose when exposed to a given temperature range. In addition, it is important that the mechanical properties of the filtration are maintained at the temperatures at which typical aerosol-generating substrates need to be heated in order to generate an aerosol. Preferably, the filtration material should be thermally stable up to 230 degrees Celsius, more preferably up to 280 degrees Celsius. This is because typical aerosol-generating substrates need to be heated to between about 100 degrees Celsius and about 280 degrees Celsius in order to generate an aerosol.

The aerosol-generating substrate reservoir may comprise a plug of filtration material, and a plurality of particles of porous element dispersed within the plug of filtration material. An aerosol-generating substrate is sorbed in the porous element. For example, the aerosolgenerating substrate reservoir may comprise a plug of cellulose acetate tow, and a plurality of activated carbon pellets, activated carbon granules, or powdered activated carbon dispersed within the cellulose acetate tow. The activated carbon pellets, granules, or powders may have any of the properties described above.

The aerosol-generating substrate reservoir may comprise a sheet-like filtration material, and a plurality of particles of porous element dispersed on the sheet-like filtration material.

The aerosol-generating substrate reservoir may comprise a plug of filtration material or a sheet-like filtration material, and a monolithic porous element within the plug of filtration material or sheet-like filtration material. For example, the aerosol-generating substrate reservoir may comprise a cylindrical monolithic portion of activated carbon surrounded by filtration material.

The provision of an aerosol-generating substrate reservoir comprising filtration material may advantageously prevent leakage of the aerosol-generating substrate sorbed in the porous element since the absorbent filtration material may effectively absorb excess aerosol-generating substrate. This may advantageously prevent aerosol-generating substrate from reaching the external surface of an aerosol-generating article comprising the aerosolgenerating substrate reservoir which may be visible to a user.

According to a second aspect of the present disclosure, there is provided an aerosolgenerating article for producing an inhalable aerosol upon heating. The aerosol-generating article may comprise an aerosol-generating substrate reservoir according to the first aspect of the present invention. The aerosol-generating article may comprise a downstream section downstream of the aerosol-generating substrate reservoir. The downstream section may comprise an aerosol-cooling element. The aerosol-cooling element may comprise a hollow tubular element. The downstream section may further comprise a mouthpiece element downstream of the aerosol-cooling element.

According to a second aspect of the present invention, there is provided an aerosolgenerating article for producing an inhalable aerosol upon heating. The aerosol-generating article comprises an aerosol-generating substrate reservoir according to the first aspect of the present invention. The aerosol-generating article comprises a downstream section downstream of the aerosol-generating substrate reservoir. The downstream section comprises an aerosol-cooling element. The aerosol-cooling element comprises a hollow tubular element. The downstream section further comprises a mouthpiece element downstream of the aerosol-cooling element.

The downstream section located downstream of the aerosol-generating substrate reservoir may comprise one or more downstream elements.

As used herein with reference to the present invention, the terms “upstream” and “downstream” describe the relative positions of elements, or portions of elements, of the aerosol-generating article in relation to the direction in which the aerosol is transported through the aerosol-generating article during use.

The downstream section comprises an aerosol-cooling element. The provision of an aerosol-cooling element may advantageously allow a vapour generated by the heating the aerosol-generating substrate reservoir to condense and nucleate to form an aerosol for inhalation by a user. In addition, the provision of an aerosol-cooling element may allow a generated aerosol to cool before inhalation by a user to prevent discomfort to a user.

The aerosol-cooling element may comprise a hollow tubular element.

As used herein with reference to the present invention, the term "hollow tubular element" is used to denote a generally elongate element defining a lumen or airflow passage along a longitudinal axis thereof. In particular, the term "tubular" will be used in the following with reference to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit establishing an uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it will be understood that alternative geometries (for example, alternative cross-sectional shapes) of the tubular element may be possible.

In the context of the present invention a hollow tubular element provides an unrestricted flow channel. This means that the hollow tubular element provides a negligible level of resistance to draw (RTD). The term “negligible level of RTD” is used to describe an RTD of less than 1 mm H2O per 10 millimetres of length of the hollow tubular element, preferably less than 0.4 mm H2O per 10 millimetres of length of the hollow tubular element, more preferably less than 0.1 mm H2O per 10 millimetres of length of the hollow tubular element.

The flow channel should therefore be free from any components that would obstruct the flow of air in a longitudinal direction. Preferably, the flow channel is substantially empty.

The aerosol-generating article may comprise a first ventilation zone at a location along the downstream section. In more detail, the aerosol-generating article may comprise a first ventilation zone at a location along the hollow tubular element. As such, fluid communication is established between the flow channel internally defined by the hollow tubular element and the outer environment.

The downstream section may further comprise a further aerosol-generating substrate. The further aerosol-generating substrate may be immediately downstream of the aerosolgenerating substrate reservoir. The further aerosol-generating substrate may abut the aerosol-generating substrate reservoir.

The upstream end of the aerosol-generating substrate reservoir may define the upstream end of the aerosol-generating article.

The further aerosol-generating substrate may be a solid aerosol-generating substrate.

The further aerosol-generating substrate may comprise homogenised plant material. The further aerosol-generating substrate may comprise tobacco. The further aerosolgenerating substrate may comprise a homogenised tobacco material.

The homogenised plant material can be provided in any suitable form.

The homogenised plant material may be in the form of one or more sheets. The homogenised plant material may be in the form of a plurality of pellets or granules. The homogenised plant material may be in the form of a plurality of strands, strips or shreds.

Where the further aerosol-generating substrate comprises a homogenised plant material, the homogenised plant material may typically be provided in the form of one or more sheets. In particular, sheets of homogenised plant material may be produced by a casting process. Preferably, sheets of homogenised plant material may be produced by a papermaking process.

The further aerosol-generating substrate may comprise cut filler. The further aerosolgenerating substrate may comprise tobacco cut filler.

As used herein with reference to the present invention, the term “cut filler” is used to describe to a blend of shredded plant material, such as tobacco plant material, including, in particular, one or more of leaf lamina, processed stems and ribs, homogenised plant material.

The further aerosol-generating substrate may comprise at least one aerosol former. The aerosol former may be any suitable known compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol. The aerosol former may be facilitating that the aerosol is substantially resistant to thermal degradation at temperatures typically applied during use of the aerosol-generating article. Suitable aerosol formers are for example to: polyhydric alcohols such as, for example, triethylene glycol, 1 ,3-butanediol, propylene glycol and glycerine; esters of polyhydric alcohols such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol former comprises one or more of glycerine and propylene glycol. The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol.

The further aerosol-generating substrate may comprise any amount of aerosol former. For example, the further aerosol-generating substrate may comprise at least 5 weight percent aerosol former, at least 6 weight percent aerosol former, at least 8 weight percent aerosol former, or at least 10 weight percent aerosol former.

The further aerosol-generating substrate may comprise no more than 20 percent aerosol former. For example, the further aerosol-generating substrate may comprise no more than 18 percent aerosol former, or no more than 15 percent aerosol former.

The further aerosol-generating substrate may comprise between 5 weight percent aerosol former and 20 percent aerosol former. For example, the further aerosol-generating substrate may comprise between 6 weight percent aerosol former and 18 percent aerosol former, between 8 weight percent aerosol former and 15 percent aerosol former, or between 10 weight percent aerosol former and 15 percent aerosol former.

Preferably, the further aerosol-generating substrate comprises about 13 weight percent aerosol former.

The downstream section may further comprise a mouthpiece element.

The mouthpiece element may be located immediately downstream of the aerosolcooling element. The mouthpiece element may comprise a filter element comprising a plug of filter material. Suitable materials for forming the mouthpiece element include filter materials, ceramic, polymer material, cellulose acetate, cardboard, zeolite or aerosol-generating substrate. Preferably, the mouthpiece element comprises a plug comprising cellulose acetate.

According to a third aspect of the present disclosure, there is provided an aerosolgenerating system for producing an inhalable aerosol. The system may comprise an aerosolgenerating article according to the second aspect of the present invention. The system may comprise an aerosol-generating device comprising a heating arrangement. According to a third aspect of the present invention, there is provided an aerosolgenerating system for producing an inhalable aerosol. The system comprises an aerosolgenerating article according to the second aspect of the present invention. The system comprises an aerosol-generating device comprising a heating arrangement.

The aerosol-generating device may comprise a body. The body of the aerosolgenerating device may define a device cavity for removably receiving the aerosol-generating article. The aerosol-generating device comprises a heating arrangement or heater for heating the aerosol-generating substrate when the aerosol-generating article is received within the device cavity.

The device cavity may be referred to as the heating chamber of the aerosol-generating device. The device cavity may extend between a distal end and a mouth, or proximal, end. The distal end of the device cavity may be a closed end and the mouth, or proximal, end of the device cavity may be an open end. An aerosol-generating article may be inserted into the device cavity, or heating chamber, via the open end of the device cavity. The device cavity may be cylindrical in shape so as to conform to the same shape of an aerosol-generating article.

The expression “received within” may refer to the fact that a component or element is fully or partially received within another component or element. For example, the expression “aerosol-generating article is received within the device cavity” refers to the aerosol-generating article being fully or partially received within the device cavity of the aerosol-generating article. When the aerosol-generating article is received within the device cavity, the aerosolgenerating article may abut the distal end of the device cavity. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may be in substantial proximity to the distal end of the device cavity. The distal end of the device cavity may be defined by an end-wall.

The aerosol-generating device may comprise an elongate heater (or heating element) arranged for insertion into an aerosol-generating article when an aerosol-generating article is received within the device cavity. The elongate heater may be arranged with the device cavity. The elongate heater may extend into the device cavity. Alternative heating arrangements are discussed further below.

The heater may be any suitable type of heater.

Preferably, the heater may externally heat the aerosol-generating article when received within the aerosol-generating device. Such an external heater may circumscribe the aerosol-generating article when inserted in or received within the aerosol-generating device.

In some embodiments, the heater is arranged to heat the outer surface of the aerosolgenerating substrate reservoir. In some embodiments, the heater is arranged for insertion into an aerosol-generating substrate reservoir when the aerosol-generating substrate reservoir is received within the cavity. The heater may be positioned within the device cavity, or heating chamber.

The aerosol-generating device may comprise a power supply. The power supply may be a DC power supply. In some embodiments, the power supply is a battery.

The heater may comprise at least one heating element. The at least one heating element may be any suitable type of heating element. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises a plurality of heating elements. The heater may comprise at least one resistive heating element. Preferably, the heater comprises a plurality of resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement may facilitate the delivery of a desired electrical power to the heater while reducing or minimising the voltage required to provide the desired electrical power. Advantageously, reducing or minimising the voltage required to operate the heater may facilitate reducing or minimising the physical size of the power supply.

The heating arrangement may comprise an inductive heating arrangement. The inductive heating arrangement may comprise an inductor coil. The aerosol-generating device may comprise a power supply configured to provide high frequency oscillating current to the inductor coil. As used herein, a high frequency oscillating current means an oscillating current having a frequency of between about 500 kHz and about 30 MHz. The aerosol-generating device may advantageously comprise a DC/AC inverter for converting a DC current supplied by a DC power supply to the alternating current. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field on receiving a high frequency oscillating current from the power supply. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field in the heating chamber. In some embodiments, the inductor coil may substantially circumscribe the heating chamber.

Where the heating arrangement comprises an inductor coil, the aerosol-generating system may comprise an inductively heated element. The inductively heated element may be a susceptor element.

As used herein with reference to the present invention, the term “susceptor element” refers to an element comprising a material that is capable of converting electromagnetic energy into heat. When a susceptor element is located in an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material. A susceptor element may be arranged such that, when the aerosol-generating article is received in the hearing chamber of the aerosol-generating device, the oscillating electromagnetic field generated by the inductor coil induces a current in the susceptor element, causing the susceptor element to heat up. In these embodiments, the aerosolgenerating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of between 1 and 5 kilo amperes per metre (kA m), preferably between 2 and 3 kA/m, for example about 2.5 kA/m. The electrically- operated aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a frequency of between 1 and 30 MHz, for example between 1 and 10 MHz, for example between 5 and 7 MHz.

The susceptor element may comprise any suitable material. The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-generating substrate. Suitable materials for the elongate susceptor element include graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminium, nickel, nickel containing compounds, titanium, and composites of metallic materials. Some susceptor elements comprise a metal or carbon. Advantageously the susceptor element may comprise or consist of a ferromagnetic material, for example, ferritic iron, a ferromagnetic alloy, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable susceptor element may be, or comprise, aluminium. The susceptor element preferably comprises more than about 5 percent, preferably more than 20 percent, more preferably more than 50 percent or more than 90 percent of ferromagnetic or paramagnetic materials. Some elongate susceptor elements may be heated to a temperature in excess of 250 degrees Celsius.

The susceptor element may comprise a non-metallic core with a metal layer disposed on the non-metallic core. For example, the susceptor element may comprise metallic tracks formed on an outer surface of a ceramic core or substrate.

The susceptor element may be located in contact with the aerosol-generating substrate reservoir. The susceptor element may be located in the aerosol-generating device. In these embodiments, the susceptor element may be located in the heating chamber. The aerosol-generating device may comprise only one susceptor element. The aerosol-generating device may comprise a plurality of susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol-generating substrate reservoir.

Alternatively or in addition, the aerosol-generating article may comprise a susceptor element. For example, one or more elongate susceptor elements may be arranged substantially longitudinally within the aerosol-generating substrate reservoir. The susceptor element may extend all the way to a downstream end of aerosolgenerating substrate reservoir. The susceptor element may extend all the way to an upstream end of the aerosol-generating substrate reservoir. In particularly preferred embodiments, the susceptor element has substantially the same length as the aerosol-generating substrate reservoir, and extends from the upstream end of the aerosol-generating substrate reservoir to the downstream end of the aerosol-generating substrate reservoir.

The susceptor element is preferably in the form of a pin, rod, strip or blade.

According to a fourth aspect of the present disclosure, there is provided a cartridge for an aerosol-generating system. The cartridge may comprise an aerosol-generating substrate reservoir according to the first aspect of the present invention. The cartridge may comprise a heating arrangement. The heating arrangement may comprise an electrical heating element arranged to heat at least a portion of the aerosol-generating substrate reservoir to generate an aerosol. The cartridge may comprise at least one cartridge electrical contact arranged to engage with corresponding at least one device electrical contact of an aerosol-generating device.

According to a fourth aspect of the present invention, there is provided a cartridge for an aerosol-generating system. The cartridge comprises an aerosol-generating substrate reservoir according to the first aspect of the present invention. The cartridge comprises a heating arrangement. The heating arrangement comprises an electrical heating element arranged to heat at least a portion of the aerosol-generating substrate reservoir to generate an aerosol. The cartridge comprises at least one cartridge electrical contact arranged to engage with corresponding at least one device electrical contact of an aerosol-generating device.

In use, the cartridge may be connected to an aerosol-generating device such that the at least one cartridge electrical contact engages with a corresponding at least one device electrical contact of an aerosol-generating device. Electrical power may then be supplied from a power supply of the aerosol-generating device to the electrical heating element which then heats the aerosol-generating substrate reservoir to generate an aerosol from the liquid aerosol-generating substrate.

The electrical heating element may be any electrical heating element. The electrical heating element may have any suitable shape or form. Examples of suitable shapes and forms include but are not limited to a band, a strip, a filament, a wire, a mesh, a flat spiral coil, fibres or a fabric.

In some preferred examples, the electrical heating element is planar. The planar electrical heating element may extend substantially in a plane. In some preferred examples, the electrical heating element comprises a mesh. The electrical heating element may comprise an array of filaments forming a mesh.

As used herein with reference to the present invention, the term "mesh" encompasses grids and arrays of filaments having spaces therebetween. The term mesh also includes woven and non-woven fabrics.

The filaments may be formed by etching a sheet material, such as a foil. This may be particularly advantageous when the electrical heater assembly comprises an array of parallel filaments.

If the electrical heating element comprises a mesh or fabric of filaments, the filaments may be individually formed and knitted together.

The electrical heating element may comprise an electrically resistive heating element. The electrical heating element may be made from any suitable electrically conductive material. Suitable materials include but are not limited to: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, constantan, nickel-, cobalt-, chromium-, aluminum-, titanium-, zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin- , gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai®, iron-aluminum based alloys and iron-manganese-aluminum based alloys. Timetai® is a registered trade mark of Titanium Metals Corporation. The electrical heating element may be made from stainless steel, for example, a 300 series stainless steel such as AISI 304, 316, 304L, 316L. In a preferred example, the electrical electrical heating element may comprise one of more of NiCr and TiZr.

Additionally, the electrical heating element may comprise combinations of the above materials. A combination of materials may be used to improve the control of the resistance of the electrical heating element. For example, materials with a high intrinsic resistance may be combined with materials with a low intrinsic resistance. This may be advantageous if one of the materials is more beneficial from other perspectives, for example price, machinability or other physical and chemical parameters. Advantageously, high resistivity heating allows more efficient use of battery energy.

The electrical heating element may be spaced apart from the aerosol-generating substrate reservoir. Preferably, the electrical heating element is in direct contact with the aerosol-generating substrate reservoir. This may advantageously provide improved and efficient heating of the aerosol-generating substrate reservoir by the electrical heating element.

The electrical heating element may be formed from an electrically conductive material deposited on to the porous element.

As used herein with reference to the present invention, the term “electrically conductive material” denotes a material having a resistivity of 1x10-2 Qm, or less.

As used herein with reference to the present invention, the term “deposited” means applied as a layer or coating by a physical or chemical process, for example in the form of a liquid, plasma or vapour which subsequently condenses or aggregates to form the electrical heating element, rather than simply being laid on or fixed to the porous element as a solid, pre-formed component. In this way, the element heating element may be integrally formed with the porous element.

The at least one cartridge electrical contact may be formed from any suitable material. Examples of suitable materials for the electrical contacts include but are not limited to copper, zinc, silver, and gold. The at least one cartridge electrical contact may be in electrical contact with the electrical heating element such that electrical power may be supplied to the electrical heating element of the heating arrangement.

According to a fifth aspect of the present disclosure, there is provided an aerosolgenerating system for producing an inhalable aerosol. The system may comprise a cartridge according to the third aspect of the present invention. The system may comprise an aerosolgenerating device. The aerosol-generating device may comprise a power supply. The aerosol-generating device may comprise at least one device electrical contact.

According to a fifth aspect of the present invention, there is provided an aerosolgenerating system for producing an inhalable aerosol. The system comprises a cartridge according to the third aspect of the present invention. The system comprises an aerosolgenerating device. The aerosol-generating device comprises a power supply. The aerosolgenerating device comprises at least one device electrical contact.

The aerosol-generating device may comprise a housing. The housing may be elongate. The housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics that are suitable for food or pharmaceutical applications, for example polypropylene, polyetheretherketone (PEEK) and polyethylene. The material is preferably light and non-brittle.

The aerosol-generating device housing may define a cavity or recess for receiving a portion of a cartridge. The aerosol-generating device may have a connection end configured to removably connect the aerosol-generating device to a cartridge. The connection end may comprise the cavity or recess for receiving the cartridge.

The aerosol-generating device may have a distal end, opposite the connection end. The distal end may comprise an electrical connector configured to connect the aerosolgenerating device to an electrical connector of an external power supply, for charging the power supply of the aerosol-generating device.

The aerosol-generating system may comprise an air inlet. The air inlet may be arranged at an interface between the cartridge and the aerosol-generating device. The aerosol-generating system may comprise an enclosed airflow passage from the air inlet to an aerosol outlet in a mouthpiece. The enclosed airflow passage may extend from the air inlet, past the heater assembly, to the aerosol outlet.

The aerosol-generating system may comprise a first airflow pathway that extends from the air inlet towards the heater arrangement in a first direction. The aerosol-generating system may comprise a second airflow pathway that extends past the electrical heating element and is configured to entrain the aerosol. The aerosol-generating system may comprise a third airflow pathway that extends from the heater arrangement to an aerosol outlet in a second direction. The second direction may be opposite to the first direction. The second airflow pathway may provide a fluid connection between the first airflow pathway and the third airflow pathway.

The power supply may be any suitable power supply. Preferably, the power supply is a DC power supply. The power supply may be a battery. The battery may be a Lithium based battery, for example a Lithium-Cobalt, a Lithium-lron-Phosphate, a Lithium Titanate or a Lithium-Polymer battery. The battery may be a Nickel-metal hydride battery or a Nickel cadmium battery. The power supply may be another form of charge storage device such as a capacitor. The power supply may be rechargeable and be configured for many cycles of charge and discharge. The power supply may have a capacity that allows for the storage of enough energy for one or more user experiences of the aerosol-generating system; for example, the power supply may have sufficient capacity to allow for the continuous generation of aerosol for a period of around six minutes, corresponding to the typical time taken to smoke a conventional cigarette, or for a period that is a multiple of six minutes. In another example, the power supply may have sufficient capacity to allow for a predetermined number of puffs or discrete activations of the aerosol-generating system.

The aerosol-generating device may comprise control circuitry. The control circuitry may comprise any suitable controller or electrical components. The controller may comprise a memory. Information for performing the above-described method may be stored in the memory. The control circuitry may comprise a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller, or an application specific integrated chip (ASIC) or other electronic circuitry capable of providing control. The control circuitry may be configured to supply power to the heating element continuously following activation of the device, or may be configured to supply power intermittently, such as on a puff-by-puff basis. The power may be supplied to the heating element in the form of pulses of electrical current, for example, by means of pulse width modulation (PWM).

The control circuitry may comprise further electronic components. For example, in some embodiments, the control circuitry may comprise any of: sensors, switches, display elements.

The aerosol-generating system may comprise a puff detector. The puff detector may be configured to detect when a user draws on the aerosol-generating system. The puff detector may be any suitable sensor that is capable of detecting when a user draws on the aerosol-generating device. For example, the puff detector may be an airflow sensor. The control circuitry may be configured to supply power to the heating element when the puff detector detects a user drawing on the aerosol-generating system.

According to a sixth aspect of the present disclosure, there is provided a method of preparing an aerosol-generating substrate reservoir. The method may comprise the step of applying a liquid aerosol-generating substrate to a porous element. The porous element may comprise activated carbon. The porous element may have a standard BET surface area of more than 100 metres squared per gram. The porous element may have a standard BET surface area of less than 600 metres squared per gram.

According to a sixth aspect of the present invention, there is provided a method of preparing an aerosol-generating substrate reservoir. The method comprises the step of applying a liquid aerosol-generating substrate to a porous element. The porous element comprises activated carbon. The porous element has a standard BET surface area of more than 100 metres squared per gram. The porous element has a standard BET surface area of less than 600 metres squared per gram.

The method may further comprise a step of agitating the liquid aerosol-generating substrate with the porous element using stirring at least 450 revolutions per minute for at least 2 hours.

The provision of an agitation step may advantageously ensure that the maximum volume of liquid aerosol-generating substrate is sorbed in the porous element.

The method may further comprise a step of drying the aerosol-generating substrate reservoir at least 60 degrees Celsius for at least 5 hours.

Features described in relation to one of the above examples may equally be applied to other examples of the present disclosure. The invention is defined in the claims. However, below there is provided a non- exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example Ex 1.An aerosol-generating substrate reservoir for use in an aerosolgenerating system, the aerosol-generating substrate reservoir comprising: a porous element comprising activated carbon.

Example Ex 2. An aerosol-generating substrate reservoir according to Ex 1 , wherein the porous element has a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent,

Example Ex 3. An aerosol-generating substrate reservoir according to Ex 1 or Ex2, further comprising an aerosol-generating substrate sorbed in the porous element.

Example Ex 4. An aerosol-generating substrate reservoir according to any preceding Example, wherein the total amount of CO2 and CO evolved from the porous element during temperature-programmed desorption (TPD) is at least 1500 micromoles per gram.

Example Ex 5. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a standard BET surface area of at least 100 metres squared per gram.

Example Ex 6. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a standard BET surface area of no more than 600 metres squared per gram.

Example Ex 7. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a pore volume measured using adsorption isotherms of either carbon dioxide (VDR (CO2)) or nitrogen (VDR (N2)) of at least 0.05 cubic centimetres per gram.

Example Ex 8. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a pore volume measured using adsorption isotherms of either carbon dioxide (VDR (CO2)) or nitrogen ( DR (N2)) of no more than 0.35 cubic centimetres per gram.

Example Ex 9. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a pore volume measured using V_meso (N2) of at least 0.01 cubic centimetres per gram.

Example Ex 10. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a pore volume measured using V_meso (N2) of no more than 0.15 cubic centimetres per gram. Example Ex 11 . An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a pore volume measured using V_meso (Hg) of at least 0.001 cubic centimetres per gram.

Example Ex 12. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a pore volume measured using V_meso (Hg) of no more than 0.1 cubic centimetres per gram.

Example Ex 13. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a total mesopore volume (VT_meso) of at least 0.01 cubic centimetres per gram.

Example Ex 14. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a total mesopore volume (VT_meso) of no more than 1 cubic centimetre per gram.

Example Ex 15. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a macropore volume (V macro) of at least 0.1 cubic centimetres per gram.

Example Ex 16. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a macropore volume (V_macro) of no more than 5 cubic centimetres per gram.

Example Ex 17. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a total pore volume (VT) of at least 0.05 cubic centimetres per gram.

Example Ex 18. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a total pore volume (VT) of no more than 3 cubic centimetres per gram.

Example Ex 19. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has a surface concentration of oxygen (Ototai) of no more than 20 percent when measured using temperature-programmed desorption (TPD).

Example Ex 20. An aerosol-generating substrate reservoir according to any preceding Example, wherein the ratio of CO2 to CO evolved from the porous element during temperature-programmed desorption (TPD) is at least 0.2.

Example Ex 21. An aerosol-generating substrate reservoir according to any preceding Example, wherein the ratio of CO2 to CO evolved from the porous element during temperature-programmed desorption (TPD) is no more than 1.5. Example Ex 22. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element exhibits a single derivative TG (DTG) peak between of 160 degrees Celsius and 300 degrees Celsius.

Example Ex 23. An aerosol-generating substrate reservoir according to any preceding Example, wherein the aerosol-generating substrate comprises glycerine.

Example Ex 24. An aerosol-generating substrate reservoir according to any preceding Example, wherein the aerosol-generating substrate comprises water.

Example Ex 25. An aerosol-generating substrate reservoir according to any preceding Example, wherein the aerosol-generating substrate comprises water and glycerine in a ratio by weight of 1 .

Example Ex 26. An aerosol-generating substrate reservoir according to any preceding Example, wherein the aerosol-generating substrate comprises nicotine.

Example Ex 27. An aerosol-generating substrate reservoir according to any preceding Example, wherein the porous element has an aerosol-generating substrate loading capacity of between 0.5 grams per gram of porous element and 1.5 grams per gram of porous element.

Example Ex 28. An aerosol-generating substrate reservoir according to any preceding Example, further comprising a filtration material.

Example Ex 29. An aerosol-generating substrate reservoir according to Example 28, porous element comprises a plurality of particle of activated carbon dispersed within the filtration material.

Example Ex 30. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising: an aerosol-generating substrate reservoir according to any preceding Example, and a downstream section downstream of the aerosol-generating substrate reservoir, the downstream section comprising an aerosol-cooling element comprising a hollow tubular element and a mouthpiece element downstream of the aerosol-cooling element.

Example Ex 31 . An aerosol-generating article according to Example 30, wherein the downstream section further comprises a further aerosol-generating substrate.

Example Ex 32. An aerosol-generating article according to Example 31 , wherein the further aerosol-generating substrate comprises tobacco.

Example Ex 33. An aerosol-generating system for producing an inhalable aerosol, the system comprising: aerosol-generating article according to any of Ex 30 to Ex 32, and an aerosol-generating device comprising a heating arrangement.

Example Ex 34. A cartridge for an aerosol-generating system, the cartridge comprising: an aerosol-generating substrate reservoir according to any of Ex 1 to Ex 29, a heating arrangement comprising: an electrical heating element arranged to heat at least a portion of the aerosol-generating substrate reservoir to generate an aerosol, and at least one cartridge electrical contact arranged to engage with corresponding at least one device electrical contact of an aerosol-generating device.

Example Ex 35. An aerosol-generating system for producing an inhalable aerosol, the system comprising: a cartridge according to Ex 34, and an aerosol-generating device, the aerosol-generating device comprising a power supply and at least one device electrical contact.

Example Ex 36. A method of preparing an aerosol-generating substrate reservoir, the method comprising the step of: applying an aerosol-generating substrate to a porous element, the porous element having a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent.

Example Ex 37. A method according to Ex 36, further comprising steps of: agitating the aerosol-generating substrate with the porous element using stirring at least 450 revolutions per minute for at least 2 hours.

Example Ex 38. A method according to Ex 36 or Ex 37, further comprising steps of: drying the aerosol-generating substrate reservoir at least 60 degrees Celsius for at least 5 hours.

Examples will now be further described with reference to the figures in which:

Figure 1 shows a cross sectional view of an aerosol-generating article according to the present invention,

Figure 2 shows a cross sectional view of a first aerosol-generating system according to the present invention,

Figure 3 shows a cross sectional view of a second aerosol-generating system according to the present invention,

Figure 4 is a graph showing the CO evolution as a function of temperature for two sample porous elements, one of which is in accordance with the present invention, and one of which is not in accordance with the present invention,

Figure 5 is a graph showing the CO2 evolution as a function of temperature for two sample porous elements, one of which is in accordance with the present invention, and one of which is not in accordance with the present invention,

Figure 6 is a graph summarising the results of a thermogravimetric (TG) analysis for a porous element according to the present invention,

Figure 7 is a graph summarising the results of a thermogravimetric (TG) analysis for a porous element according to the present invention, and Figure 8 shows a cross sectional view of a further aerosol-generating article according to the present invention.

The aerosol-generating article 100 shown in Figure 1 extends from an upstream end 101 to a downstream end 102. The aerosol-generating article 100 comprises an aerosolgenerating substrate reservoir 103 at the upstream end 101 of the aerosol-generating article 100. The aerosol-generating substrate reservoir 103 comprises a porous element. An aerosol-generating substrate is sorbed in the porous element. The aerosol-generating substrate is a liquid aerosol-generating substrate. The liquid aerosol-generating substrate comprises nicotine, glycerine, and water.

The aerosol-generating substrate reservoir 103 comprises a porous element formed from activated carbon. The porous element has a standard BET surface area of between 100 metres squared per gram and 600 metres squared per gram.

The aerosol-generating article 100 further comprises a downstream section located immediately downstream of the aerosol-generating substrate reservoir 103.

The downstream section comprises a hollow tubular element 104 and a mouthpiece element 106 downstream of the hollow tubular element 104.

The hollow tubular element 104 defines a hollow section of the aerosol-generating article 100. The hollow tubular element 104 does not substantially contribute to the overall RTD of the aerosol-generating article 100. In more detail, an RTD of the hollow tubular element 104 is about 0 mm H2O.

The hollow tubular element 104 is provided in the form of a hollow cylindrical tube made of cardboard. The hollow tubular element 104 defines an internal cavity 105 that extends all the way from an upstream end of the hollow tubular element 104 to a downstream end of the hollow tubular element 104. The internal cavity 105 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity 105.

The hollow tubular element 104 has a length of about 21 millimetres, an external diameter of about 7.2 millimetres, and an internal diameter of about 6.7 millimetres. Thus, a thickness of a peripheral wall of the hollow tubular cooling element 20 is about 0.25 millimetres.

The aerosol-generating article 100 comprises a ventilation zone 108 provided at a location along the hollow tubular element 104. The ventilation zone 108 comprises a circumferential row of openings or perforations circumscribing the hollow tubular element 104. The perforations of the ventilation zone 108 extend through the wall of the hollow tubular element 104, in order to allow fluid ingress into the internal cavity 105 from the exterior of the article 100. A ventilation level of the aerosol-generating article 100 is about 40 percent. The mouthpiece element 106 extends from the downstream end of the hollow tubular element 104 to the downstream end 102 of the aerosol-generating article 100. The mouthpiece element 106 has a length of about 7 millimetres. An external diameter of the mouthpiece element 106 is about 7.2 millimetres. The mouthpiece element 106 comprises a low-density, cellulose acetate filter segment. The RTD of the mouthpiece element 106 is about 8 mm H2O. The mouthpiece element 106 may be individually wrapped by a plug wrap (not shown).

The aerosol-generating article 100 comprises a wrapper 107 circumscribing the aerosol-generating substrate reservoir 103, the hollow tubular element 104, and the mouthpiece element 106. The ventilation zone 108 may also comprise a circumferential row of perforations provided through the wrapper 107.

The aerosol-generating article 100 has an overall length of about 45 millimetres and an external diameter of about 7.2 millimetres.

Figure 2 illustrates a first aerosol-generating system 200 according to the present invention. The first aerosol-generating system 200 comprises the first aerosol-generating article 100 of Figure 1 , and a downstream portion of a first aerosol-generating device 250. The first aerosol-generating device 250 comprises a housing (or body) 201 , extending between a downstream end and an upstream end (not shown). The housing 201 defines a heating chamber 202 for receiving an aerosol-generating article 100. The heating chamber 202 is defined by a closed, upstream end and an open, downstream end. The downstream end of the heating chamber 202 is located at the downstream end of the aerosol-generating device 250. The aerosol-generating article 100 is configured to be received through the open, downstream end of the heating chamber 202 and is configured to abut a closed, upstream end of the heating chamber 202, when the aerosol-generating article 100 is fully received in the heating chamber 202.

The aerosol-generating device 250 further comprises a heater arrangement 203 and a power source 204 for supplying power to the heater arrangement 203. A controller (not shown) is also provided to control such supply of power to the heater arrangement 203. The heater arrangement 203 is configured to controllably heat the aerosol-generating article 100 during use, when the aerosol-generating article 100 is fully received within the heating chamber 202.

The heater arrangement 203 extends from an upstream end to a downstream end defining a heating zone. The heater arrangement 203 is the same length as the aerosolgenerating substrate reservoir 103 such that when the aerosol-generating article 100 is fully received within the heating chamber 202, the entire length of the aerosol-generating substrate reservoir 103 is received within the heating zone to provide optimal heating of the aerosol- generating substrate reservoir 103. The heater arrangement 203 comprises a resistive heating element.

The ventilation zone 108 is arranged to be exposed when the aerosol-generating article 100 is fully received within the heating chamber 202.

In use, the aerosol-generating article 100 is fully received within the heating chamber 202 of the aerosol-generating device 250. The heater arrangement 203 is activated by the controller and the resistive heating element generates heat which is transferred directly to the aerosol-generating substrate reservoir 103 which is disposed within the heating zone. This generates an aerosol in the aerosol-generating substrate reservoir 103. When a pressure drop is applied to the downstream end 102 of the aerosol-generating article 100, air is drawn into the heating chamber 202 and into the aerosol-generating substrate reservoir 103. The aerosols generated in the aerosol-generating substrate reservoir 103 is entrained in the airflow which then passes through the downstream section before leaving through the downstream end 102 of the aerosol-generating article 100.

Figure 3 illustrates a second aerosol-generating system 300 according to the present invention. The second aerosol-generating system 300 comprises two main components, a cartridge 310 and a main body part or aerosol-generating device 320. The cartridge 310 is removably connected to the aerosol-generating device 320 at the cartridge/device interface 340. The aerosol-generating device 320 comprises a device housing that contains a power source in the form of a battery 321 , which in this example is a rechargeable lithium ion battery, and control circuitry 322. The aerosol-generating device 320 further comprises a device electrical contact 323 for engaging with a cartridge electrical contact 313 to allow power to be supplied from the aerosol-generating device 320 to the cartridge 310. The aerosol-generating system 300 is portable and has a size comparable to a conventional cigar or cigarette. A mouthpiece 314 is arranged at a mouth end of the cartridge 310.

The cartridge 310 comprises an aerosol-generating substrate reservoir 311. The aerosol-generating substrate reservoir 311 comprises a porous element. An aerosolgenerating substrate is sorbed in the porous element. The aerosol-generating substrate is a liquid aerosol-generating substrate. The liquid aerosol-generating substrate comprises nicotine, glycerine, and water.

The aerosol-generating substrate reservoir 311 comprises a porous element formed from activated carbon. The porous element a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent.

The cartridge 310 further comprises an electrical heating element 312 arranged to heat at least a portion of the aerosol-generating substrate reservoir 311 to generate an aerosol. The electrical heating element 312 is a resistive heating element comprising a track arranged in a serpentine manner on the surface and in direct contact with the aerosolgenerating substrate reservoir 311 .

The cartridge 310 further comprises a cartridge electrical contact 313 configured to engage with the device electrical contact 323 to allow power to be supplied from the battery 321 to the electrical heating element 312.

In use, the cartridge 310 is attached to the aerosol-generating device 320 such that the device electrical contact 323 engages with the cartridge electrical contact 313. When activated, power from the battery 321 is supplied through the electrical contacts 313, 323 to the electrical heating element 312. The electrical heating element 312 heats the aerosolgenerating substrate reservoir 311 to generate an aerosol. The aerosol then leaves the cartridge 310 through the mouthpiece 314.

Table 1 summarises the properties of 12 different porous elements for use in an aerosol-generating substrate reservoir, samples A-L. Each of the samples comprises activated carbon, but the specific variety of the activated carbon varies between samples A-L.

The surface concentration of oxygen (Ototai) when measured using temperature programmed desorption was determined. These data are shown in the column identified as “Otot (WT%)”. As can be seen from the oxygen concentration data, samples C, F, J and K are according to the present invention since they have a surface concentration of oxygen (Ototai) of at least 3 weight percent. Samples G, H, I, and L are not in accordance with the present invention since they all have surface concentration of oxygen (Ototai) of less than 3 weight percent.

The N2 adsorption isotherms were also used to determine the pore volume VDR (N2) by application of the Dubinin-Radushkevich equation for each sample. These data are shown in the column identified as “V DR N2 (cm³/g)”.

The CO2 adsorption isotherms were used to determine the pore volume VDR (CO2), also by application of the Dubinin-Radushkevich equation for each sample. These data are shown in the column identified as “V DR CO2 (cm³/g)”.

The difference between the pore volume DR (N2) and pore volume VDR (CO2) is shown in the column identified as “V DR N2 -V DR CO2 (cm³/g)”. This parameter “V DR N2 -V DR CO2 (cm³/g)” may provide an estimate of the mean micropore size in the porous element. When V DR N2 -V DR CO2 = 0, the mean micropore size is between about 0.7 nanometres and 0.8 nanometres. When V DR N2 -V DR CO2 > 0, the mean micropore size is greater than about 0.8 nanometres. When V DR N2 -V DR CO2 < 0, the mean micropore size is less than about 0.7 nanometres. The amount of CO2 and CO evolved from each of samples C, and F-L during a temperature-programmed desorption (TPD) was determined. These data are shown in the columns identified as “CO2 (micromol/g)” and “CO (micromol/g)” respectively. TPD test was conducted using a differential scanning calirometer-thermogravimetric analyser (DSC-TGA TA, Simultaneous SDT 2960) coupled to a mass spectrometer (Balzers, OmniStar). Each porous element sample comprised 10 milligrams of the activated carbon. The samples were heated to 950 degrees Celsius at a heating rate of 20 degrees Celsius per minute under a helium flow rate of 100 millilitres per minute. The gas evolved from the surface decomposition is then analysed using a Balzers-Pfeiffer Vacuum mass spectrometer.

Figure 4 is a graph showing the CO evolution as a function of temperature during the TPD experiment detailed above. The CO evolution in micromoles per gram seconds is plotted on the vertical axis 401 and the temperature in degrees Celsius is plotted on the horizontal axis 402. The graph in Figure 4 plots the CO evolution as a function of temperature for sample H (404) which is not according to the invention, and for sample C (403) which is in accordance with the present invention.

Figure 5 is a graph showing the CO2 evolution as a function of temperature during the TPD experiment detailed above. The CO2 evolution in micromoles per gram seconds is plotted on the vertical axis 501 and the temperature in degrees Celsius is plotted on the horizontal axis 502. The graph in Figure 5 plots the CO2 evolution as a function of temperature for sample H (504) which is not according to the invention, and for sample C (503) which is in accordance with the present invention.

As can be seen from Figures 4 and 5, porous elements which are in accordance with the present invention exhibit substantially higher CO and CO2 evolution. This demonstrates a considerably higher surface oxygen content compared to samples which are not in accordance with the present invention.

The ratio of CO2 to CO evolved from each of samples C, and F-L during a temperatureprogrammed desorption (TPD) is shown in the column identified as “CO2/CO”.

Each porous element sample was combined with a liquid aerosol-generating substrate as described below. A liquid aerosol-generating substrate was prepared by adding 1 gram of water to 1 gram of glycerine (99%). The water/glycerine mixture was added to 1 gram of activated carbon of each sample. The carbon and water/glycerine mixture were stirred at 500 rpm for 3 hours. The impregnated activated carbon samples were dried at 60 degrees Celsius overnight.

Following this sample preparation, the glycerine desorption properties of each sample were determined according to the following method. Each sample was subjected to a simultaneous thermogravimetry (TG)-temperature programmed desorption (TPD) analysis. 10 milligrams of each impregnated carbon sample was heated in an airflow of 60 millilitres per minute at a variety of heating rates (10, 25, and 50 degrees Celsius per minute). The gas evolved from each sample was analysed by a mass spectrometer (Aeolos QMS 403 Quadro, Netzsch) with a fused silica TGA-transfer line operating at 300 degrees Celsius, allowing the simultaneous recording of weight loss and analysis of evolved gases.

The thermogravimetric (TG) and derivative TG (DTG) values were plotted as a function of temperature to determine how the desorption of glycerine from each sample varies as each sample is heated. The temperature at which glycerine desorption begins for each sample is shown in the column identified as “T desorption starts (°C)”. The temperature at which glycerine desorption ends for each sample is shown in the column identified as “T desorption ends (°C)”. The temperature at which the rate of glycerine desorption first peaks is shown in the column identified as “T peak 1 (°C)”. For some samples, the rate of glycerine desorption peaks for a second time at a higher temperature. This second peak is shown in the column identified as “T peak 2 (°C)”.

As can be seen from Table 1 , samples C, F, J and K do not exhibit a second glycerine desorption peak, and only exhibit one glycerine desorption peak. As described above, samples C, F, J and K are according to the present invention since they have a surface concentration of oxygen (Ototai) of at least 3 weight percent. As a result, these samples exhibit more predictable and consistent desorption properties leading to an improved user experience.

Samples D, E, G-l, and L all exhibit a second glycerine desorption peak at a higher temperature than the first glycerine desorption peak. The inventors of the present invention have identified that the provision of a second glycerine desorption peak has an undesirable effect on the aerosol delivery and therefore the user experience.

In addition, Table 1 shows the total amount of CO2 and CO evolved from the porous element during temperature-programmed desorption (TPD). As can be seen, samples C, F, J, and K exhibit CO2 and CO evolution of at least 1500 micromoles per gram. Samples C, F, J, and K also do not exhibit a second glycerine desorption peak, and only exhibit one glycerine desorption peak. As a result, these samples exhibit more predictable and consistent desorption properties leading to an improved user experience.

Figure 6 shows the thermogravimetric mass decrease (TG) and the derivative TG (DTG) plots as a function of temperature for sample C which is in accordance with the present invention. Mass percentage decrease of the sample measured using TG analysis is plotted on the left vertical axis 601 , the derivative of TG (DTG) in mass percentage per minute is plotted on the right vertical axis 602, and the temperature in degrees Celsius is plotted on the horizontal axis 603. Line 605 shows the percentage mass change for sample C which is saturated with the water/glycerine mixture during a heating to about 300 degrees Celsius. Line 604 shows the DTG plot for sample C which is saturated with the water/glycerine mixture during a heating to about 300 degrees Celsius, this line essentially representing the rate of change of mass of the sample as a function of time.

As can be seen, the DTG plot 604 includes one peak before dropping rapidly. For comparison, line 606 shows the percentage mass change for sample C which has not been combined with a water/glycerine mixture during a heating to about 300 degrees Celsius. As can be seen, the mass change is minimal compared to the sample C which includes the water/glycerine mixture indicating that the majority of the mass change is attributable to aerosol generation from the water/glycerine mixture.

Figure 7 shows the thermogravimetric mass decrease (TG) and the derivative TG (DTG) plots as a function of temperature for sample H which is not in accordance with the present invention. Mass percentage decrease of the sample measured using TG analysis is plotted on the left vertical axis 701 , the derivative of TG (DTG) in mass percentage per minute is plotted on the right vertical axis 702, and the temperature in degrees Celsius is plotted on the horizontal axis 703. Line 705 shows the percentage mass change for sample H which is saturated with the water/glycerine mixture during a heating to about 300 degrees Celsius. Line 704 shows the DTG plot for sample H which is saturated with the water/glycerine mixture during a heating to about 300 degrees Celsius, this line essentially representing the rate of change of mass of the sample as a function of time.

As can be seen, the DTG plot 704 includes two peaks. For comparison, line 706 shows the percentage mass change for sample H which has not been combined with a water/glycerine mixture during a heating to about 300 degrees Celsius. As can be seen, the mass change is minimal compared to the sample H which includes the water/glycerine mixture indicating that the majority of the mass change is attributable to aerosol generation from the water/glycerine mixture.

Figure 8 shows a further aerosol-generating article 800 according to the present invention. The aerosol-generating article 800 shown in Figure 8 includes all of the features of the aerosol-generating article 100 shown in Figure 1 , like references are used to refer to the same features.

In addition to the previously described features, the downstream section of the aerosolgenerating article 800 of Figure 8 includes a further aerosol-generating substrate 809. The further aerosol-generating substrate 809 is immediately downstream of the aerosol-generating substrate reservoir 803. The further aerosol-generating substrate 809 abuts the aerosolgenerating substrate reservoir 803. The further aerosol-generating substrate 809 comprises a plug of homogenised tobacco material and an aerosol former. The aerosol former comprises glycerine. The further aerosol-generating substrate 809 comprises about 13 weight percent aerosol former.

The aerosol-generating substrate reservoir 803 comprises a plug of cellulose acetate tow. The aerosol-generating substrate reservoir 803 comprises a plurality of particles of porous element 810 dispersed within the plug of cellulose acetate tow. The plurality of particles of porous element 810 are formed from activated carbon. An aerosol-generating substrate is sorbed in the porous element 810. The aerosol-generating substrate is a liquid aerosol-generating substrate. The liquid aerosol-generating substrate comprises nicotine, glycerine, and water. The porous element 810 has a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent.

Table 1

Claims

What is claimed:

1 . An aerosol-generating substrate reservoir for use in an aerosol-generating system, the aerosol-generating substrate reservoir comprising: a porous element comprising activated carbon, the porous element having a surface concentration of oxygen (Ototai) when measured using temperature programmed desorption of at least 3 weight percent, and an aerosol-generating substrate sorbed in the porous element.

2. An aerosol-generating substrate reservoir according to claim 1 , wherein the total amount of CO2 and CO evolved from the porous element during temperature-programmed desorption is at least 1500 micromoles per gram.

3. An aerosol-generating substrate reservoir according to claim 1 or claim 2, wherein the porous element has a surface concentration of oxygen (Ototai) of no more than 20 percent when measured using temperature-programmed desorption (TPD).

4. An aerosol-generating substrate reservoir according to any preceding claim, wherein the porous element has an aerosol-generating substrate loading capacity of between 0.5 grams per gram of porous element and 1 .5 grams per gram of porous element.

5. An aerosol-generating substrate reservoir according to any preceding claim, wherein the porous element has a pore volume measured using adsorption isotherms of either carbon dioxide (VDR (CO2)) or nitrogen (VDR (N2)) of at least 0.05 cubic centimetres per gram.

6. An aerosol-generating substrate reservoir according to any preceding claim, wherein the porous element has a pore volume measured using adsorption isotherms of either carbon dioxide (VDR (CO2)) or nitrogen ( DR (N2)) of no more than 0.35 cubic centimetres per gram.

7. An aerosol-generating substrate reservoir according to any preceding claim, wherein the porous element has a pore volume measured using V_meso (N2) of at least 0.01 cubic centimetres per gram.

8. An aerosol-generating substrate reservoir according to any preceding claim, wherein the porous element has a pore volume measured using V_meso (N2) of no more than 0.15 cubic centimetres per gram.

9. An aerosol-generating substrate reservoir according to any preceding claim, wherein the porous element has a pore volume measured using V_meso (Hg) of at least 0.001 cubic centimetres per gram.

10. An aerosol-generating substrate reservoir according to any preceding claim, wherein the porous element has a pore volume measured using V_meso (Hg) of no more than 0.1 cubic centimetres per gram.

11. An aerosol-generating substrate reservoir according to any preceding claim, wherein the porous element has a total mesopore volume (VT_meso) of at least 0.01 cubic centimetres per gram.

12. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising: an aerosol-generating substrate reservoir according to any preceding claim, and a downstream section downstream of the aerosol-generating substrate reservoir, the downstream section comprising an aerosol-cooling element comprising a hollow tubular element and a mouthpiece element downstream of the aerosol-cooling element

13. An aerosol-generating system for producing an inhalable aerosol, the system comprising: aerosol-generating article according to claim 12, and an aerosol-generating device comprising a heating arrangement.

14. A cartridge for an aerosol-generating system, the cartridge comprising: an aerosol-generating substrate reservoir according to any of claims 1 to 11 , a heating arrangement comprising: an electrical heating element arranged to heat at least a portion of the aerosolgenerating substrate reservoir to generate an aerosol, and at least one cartridge electrical contact arranged to engage with corresponding at least one device electrical contact of an aerosol-generating device.

15. An aerosol-generating system for producing an inhalable aerosol, the system comprising: a cartridge according to claim 14, and an aerosol-generating device, the aerosol-generating device comprising a power supply and at least one device electrical contact.