RU2789176C2 - Porous metal oxide microspheres - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be used for coloring consumer products. Porous microspheres containing metal oxide are proposed, where microspheres have an average diameter from about 0.5 mcm to about 100 mcm and average porosity from about 0.10 to about 0.80. Porous microspheres have more than one pore population, wherein each has an average pore diameter. Each population has a different average pore diameter, while average pore diameters are from about 50 nm to about 999 nm. An option of porous microspheres and options of compositions useful as structural dyes are also proposed.

EFFECT: inventions allow for obtainment of structural dyes having high stability and environmental friendliness.

17 cl, 4 dwg, 8 ex

Description

Disclosed are porous metal oxide microspheres, methods for their preparation and their applications. Microspheres are suitable, for example, for use as structural dyes.

State of the art

Traditional pigments and dyes develop color by absorbing and reflecting light based on their chemical structure. Structural dyes exhibit color through light interference effects based on physical structure rather than chemical structure. Structural dyes are found in nature, for example, in bird feathers, butterfly wings, and some gemstones. Structural dyes are materials containing microscopically structured surfaces small enough to interfere with visible light and produce color. Such materials may be based on photonic materials, including, but not limited to, opals, reverse opals, photonic beads, photonic spheres, or composite photonic crystals. The term "photonic material" refers to a material having a degree of periodic changes in its structure.

Structural dyes can exhibit high stability. Accordingly, structural dyes are desirable that exhibit different colors of visible light visible to the naked eye when present in bulk. Such structural dyes may be incorporated into consumer products as a replacement for less stable and/or less environmentally friendly pigments or dyes.

Some porous metal oxide microspheres have been found to have a high color rendering quality. The microspheres provide the color visible in the mass.

The essence of the invention

Accordingly, a method is disclosed for preparing polymeric microspheres containing polydisperse polymeric nanospheres, the method comprising forming a liquid solution or dispersion of monodisperse polymeric nanoparticles; the formation of at least one additional liquid solution or dispersion of monodisperse polymeric nanoparticles; mixing each of the solutions or dispersions together; the formation of droplets of the mixture; and drying the droplets to provide polymeric microspheres containing polydisperse polymeric nanospheres; where the average diameters of the monodisperse polymeric nanoparticles of each of the solutions or dispersions are different.

Also disclosed are polymeric microspheres containing more than one population of monodisperse polymeric nanospheres, where each population of monodisperse polymeric nanospheres has different average diameters. A bulk sample of the polymeric microspheres may exhibit color as seen by the human eye.

Also disclosed is a method for producing porous metal oxide microspheres, the method comprising forming a liquid solution or dispersion of monodisperse polymer nanoparticles; the formation of at least one additional liquid solution or dispersion of monodisperse polymeric nanoparticles; mixing each of the solutions or dispersions together; where the metal oxide is added to one or more of the solutions or suspensions and/or where the metal oxide is added to the mixture to form a liquid dispersion of polymer nanoparticles and metal oxide; formation of liquid droplets of the liquid dispersion; drying drops to provide polymer matrix microspheres containing polydisperse polymer nanospheres and metal oxide; and removing the polymeric nanospheres from the matrix microspheres to provide porous metal oxide microspheres; where the average diameters of monodisperse polymeric nanoparticles of each of the solutions or dispersions are different.

Also disclosed are porous metal oxide-containing microspheres, wherein the microspheres have an average diameter of about 0.5 microns to about 100 microns and an average porosity of about 0.10 to about 0.90 or about 0.10 to about 0.80; where the porous microspheres have more than one population of pores, each population having an average pore diameter, where each population has a different average pore diameter; and where the average pore diameters are from about 50 nm to about 999 nm; for example, where the microspheres have a first population of pores having an average pore diameter of from about 50 nm to about 999 nm, and a second population of pores having an average pore diameter of from about 50 nm to about 999 nm, where the first and second average pore diameters are different.

Also disclosed are porous microspheres containing a metal oxide, where a bulk sample of the porous microspheres exhibits a color observed by the human eye.

Also disclosed are compositions containing a support and microspheres according to the present invention; for example, where the compositions are aqueous formulations, oil-based formulations, coating formulations, paints, foodstuffs, plastics, cosmetic formulations, or materials for medical or safety uses.

Brief description of the drawings

The disclosure described herein is illustrated by way of example, but as a limitation, in the accompanying drawings. For simplicity and clarity of illustration, the features shown in the drawings are not necessarily drawn to scale. For example, some features may be exaggerated relative to other features for clarity. In addition, where deemed appropriate, reference numerals are repeated throughout the drawings to designate corresponding or similar elements.

On FIG. 1 shows the general scheme for obtaining porous microspheres according to the present invention.

On FIG. 2 shows a scanning electron microscope (SEM) image of polymer matrix microspheres according to an embodiment of the present invention.

On FIG. 3 shows an SEM image of porous silica microspheres according to an embodiment of the present invention.

On FIG. 4 depicts a spray drying process in accordance with some embodiments of the present invention.

Detailed description of the invention

Metal oxide microspheres according to the present invention or photonic beads can be obtained using a polymeric temporary matrix. According to one embodiment, an aqueous colloidal dispersion is prepared containing polymeric nanoparticles and a metal oxide, the polymeric particles being typically nanosized. The aqueous colloidal dispersion is mixed with the continuous oil phase, for example in a microfluidic device, to form a water-in-oil emulsion. Aqueous drops of the emulsion are obtained, collected and dried to form microspheres containing polymer nanoparticles and metal oxide. The polymer nanoparticles (nanospheres) are then removed, for example by calcination, to provide micron-sized spherical metal oxide particles (microspheres) having a high degree of porosity and nano-sized pores. The microspheres can have different pore diameters, with the result that the polymer particles are polydisperse.

On FIG. 1 shows the general scheme for obtaining porous microspheres according to the present invention. An emulsion droplet containing polymeric nanospheres and metal oxide is dried to remove the solvent, obtaining an assembled microsphere containing polymeric nanospheres with metal oxide in the interstitial spaces between the polymeric nanospheres (matrix microsphere or "straight structure"). Polymer nanospheres are polydisperse. Polymeric nanospheres define the interstitial space. Calcination removes the polymer, providing a metal oxide microsphere of the present invention with high porosity or void volume (reverse structure).

The porous metal oxide microspheres preferentially sinter, resulting in a continuous solid structure that is thermally and mechanically stable.

In some embodiments, the formation and collection of droplets is carried out in a microfluidic device. Microfluidic devices are, for example, narrow channel devices having a micron-sized droplet generating unit, adapted to produce droplets of uniform size, connected to a storage reservoir. Microfluidic devices, for example, comprise a droplet generating assembly having a channel width of about 10 µm to about 100 µm. The devices are, for example, made from polydimethylsiloxane (PDMS) and can be fabricated, for example, by soft lithography. The emulsion can be prepared inside the apparatus by pumping the aqueous dispersed phase and the oily continuous phase at the indicated rates into the apparatus where mixing takes place to form emulsion droplets. Alternatively, an oil-in-water emulsion may be used.

и включает, например, шприцевой насос и пульсационный узел. Устройство вибрирующего сопла также может содержать клапан регулирования давления.In some embodiments, vibrating nozzle techniques may be used. According to these techniques, a liquid dispersion is obtained, droplets are formed, and the droplets are dropped into a continuous phase bath. The drops are then dried and calcined. Vibrating nozzle device supplied

and includes, for example, a syringe pump and a pulse assembly. The vibrating nozzle device may also include a pressure control valve.

The polymeric nanoparticles of the present invention have an average diameter of about 50 nm to about 999 nm. Polymer nanospheres are polydisperse. According to the present invention, a polydisperse sample of polymer nanospheres contains more than one monodisperse population of polymer nanospheres, that is, at least first and second monodisperse populations of polymer nanospheres, where the first and second average particle sizes are different.

Suitable matrix polymers include thermoplastic polymers. For example, the matrix polymers are selected from the group consisting of poly(meth)acrylic acid, poly(meth)acrylates, polystyrenes, polyacrylamides, polyvinyl alcohol, polyvinyl acetate, polysterols, polyurethanes, polyethylene, polypropylene, polylactic acid, polyacrylonitrile, polyvinyl ethers, their derivatives, their salts, their copolymers and combinations thereof. For example, the polymer is selected from the group consisting of polymethyl methacrylate, polyethyl methacrylate, poly(n-butyl methacrylate), polystyrene, poly(chlorostyrene), poly(alpha-methylstyrene), poly(N-methylolacrylamide), styrene/methyl methacrylate copolymer, polyalkylated acrylate, polyhydroxyl acrylate, polyaminoacrylate, plicyanoacrylate, polyfluorinated acrylate, poly(N-methylolacrylamide), polyacrylic acid, polymethacrylic acid, methyl methacrylate/ethyl acrylate/acrylic acid copolymer, styrene/methyl methacrylate/acrylic acid copolymer, polyvinyl acetate, polyvinylpyrrolidone, polyvinylcaprolactone, polyvinylcaprolactam, their derivatives, their salts and their combinations.

According to certain embodiments of the present invention, the polymer matrices include polystyrenes, including polystyrene and polystyrene copolymers. Polystyrene copolymers include copolymers with water soluble monomers such as polystyrene/acrylic acid, polystyrene/poly(ethylene glycol)methacrylate, and polystyrene/styrenesulfonate.

Metal oxides according to the present invention include oxides of transition metals, metalloids and rare earth metals, for example, silicon oxide, titanium oxide, alumina, zirconium oxide, cerium oxide, iron oxides, zinc oxide, indium oxide, tin oxide, chromium oxide, mixed metal oxides , their combinations, and the like.

The ratio wt./wt. (w/w) of polymer nanoparticles and metal oxide is, for example, from about 0.1/1 to about 10.0/1 or from about 0.5/1 to about 10.0/1.

The continuous oil phase contains, for example, an organic solvent, silicon oil or fluorinated oil. According to the present invention, "oil" means an organic phase immiscible with water. Organic solvents include hydrocarbons such as heptane, hexane, toluene, xylene and the like, as well as alkanols such as methanol, ethanol, propanol, etc.

The emulsion droplets are collected, dried, and the polymer is removed. Drying is carried out, for example, by microwave irradiation, in a thermal oven, under vacuum, in the presence of a desiccant, by spray drying techniques, or a combination thereof.

Removal of the polymer can be carried out, for example, by calcination, pyrolysis or by means of a solvent (solvent removal). Calcination is carried out according to some embodiments at temperatures of at least about 200°C, at least about 500°C, at least about 1000°C, from about 200°C to about 1200°C, or from about 200°C to about 700°C. The calcination may be carried out for a suitable period of time, for example, from about 0.1 hour to about 12 hours, or from about 1 hour to about 8.0 hours. In other embodiments, the calcination may be carried out for at least about 0.1 hour, at least about 1 hour, at least about 5 hours, or at least about 10 hours.

Alternatively, a liquid dispersion containing polymer nanoparticles and a metal oxide is formed with an oily dispersed phase and a continuous aqueous phase to form an oil-in-water emulsion. Oil drops can be collected and dried just like water drops.

Alternatively, a liquid dispersion of polymer nanoparticles and metal oxide is prepared and spray dried to form polymer matrix microspheres without forming a liquid-in-liquid emulsion. In some embodiments of spray drying techniques, the liquid solution or dispersion is fed (eg, pumped) into a spray nozzle associated with a pressurized gas inlet. The flow of incoming material is pumped through the spray nozzle to form liquid droplets. The droplets are surrounded by a preheated gas in the evaporation chamber, which causes the solvent to evaporate to form solid particles. The dried particles are carried by the drying gas through the cyclone and deposited in the collection chamber. Gases include nitrogen and/or air. According to an embodiment of the spray drying process of the present invention, the liquid feed stream contains water or an oil phase, polymer particles, and optionally a metal oxide. Polymeric microspheres are provided containing polymeric nanospheres with optional metal oxide in the interstitial spaces between the polymeric nanospheres. Polymeric nanospheres define interstitial spaces. Spray drying techniques include jet spray drying methods and equipment.

In the spray drying techniques of the present invention, air can be considered a continuous phase with a dispersed liquid phase (liquid-in-gas emulsion). According to certain embodiments of the present invention, spray drying includes an inlet temperature of any of about 100°C, about 105°C, about 110°C, about 115°C, about 120°C, about 130°C, about 140°C, about 150°C, about 160°C or about 170°C to any of about 180°C, about 190°C, about 200°C, about 210°C, about 215°C or about 220°C. In some embodiments, a pumping rate (flow rate of incoming material) is used from any of about 1 ml/min, about 2 ml/min, about 5 ml/min, about 6 ml/min, about 8 ml/min, about 10 ml/min. min, about 12 ml/min, about 14 ml/min, or about 16 ml/min to any of about 18 ml/min, about 20 ml/min, about 22 ml/min, about 24 ml/min, about 26 ml/min min, about 28 ml/min or about 30 ml/min. Spray drying techniques are disclosed in, for example, US2016/0170091.

On FIG. 4 depicts a spray drying process in accordance with some embodiments of the present invention.

In some embodiments of spray drying techniques, the liquid solution or dispersion is fed into a spray nozzle associated with a pressurized gas inlet. The flow of incoming material is pumped through the spray nozzle to form liquid droplets. The droplets are surrounded by a preheated gas in the evaporation chamber, which causes the solvent to evaporate to form solid particles. The dried particles are carried by the drying gas through the cyclone and deposited in the collection chamber. Gases include nitrogen and/or air. According to an embodiment of the spray drying process of the present invention, the liquid feed stream contains water, polymeric nanoparticles, and metal oxide.

The microspheres are spherical or spherical-like in shape and on a micron scale, eg, have an average diameter of about 0.5 micron (μm) to about 100 μm. The polymeric nanoparticles used as the matrix are also spherical and nanosized, having an average diameter of, for example, from about 50 nm to about 999 nm. The metal oxide used can also be in the form of particles, the particles being nanosized.

The metal oxide of the dispersion may be provided as a metal oxide, or may be provided from a metal oxide precursor, for example by a sol-gel method.

Drying the polymer/metal oxide droplets and removing the polymer provides microspheres having voids (pores). Typically, in the methods of the present invention, each drop provides one microsphere. The pore diameters depend on the size of the polymer particles. Some "shrinkage" or compaction may occur upon removal of the polymer, providing pore sizes somewhat smaller than the original polymer particle size, eg, about 10% to about 40% less than the polymer particle size. The pore diameters change as the size of the polymer particles changes (they are polydisperse).

Pore diameters may be in the range of about 50 nm to about 999 nm according to some embodiments of the present invention.

The average porosity of the metal oxide microspheres of the present invention may be relatively high, for example, from about 0.10 or about 0.30 to about 0.80 or about 0.90. The average porosity of a microsphere means the total pore volume as a fraction of the volume of the entire microsphere. The average porosity can be called "volume fraction".

In some embodiments, the porous microsphere may have a hard core (center) where the porosity is generally directed towards the outer surface of the microsphere. According to other embodiments, the implementation of the porous microsphere may have a hollow core, where the main part of the porosity is directed inside the microsphere. In other embodiments, porosity may be distributed throughout the volume of the microsphere. In other embodiments, the porosity may exist as a gradient, with higher porosity towards the outer surface of the microsphere and less or no porosity (solid) towards the center; or with less porosity towards the outer surface and with higher or full porosity (hollow) towards the center.

For any porous microsphere, the average microsphere diameter is greater than the average pore diameter, e.g., the average microsphere diameter is at least about 25 times, at least about 30 times, at least about 35 times, or at least about 40 times larger than the average pore diameter.

In some embodiments, the ratio of mean microsphere diameter to mean pore diameter is, for example, from any of about 40/1, about 50/1, about 60/1, about 70/1, about 80/1, about 90/1, about 100/1, about 110/1, about 120/1, about 130/1, about 140/1, about 150/1, about 160/1, about 170/1, about 180/1 or about 190/1 to any of about 200/1, about 210/1, about 220/1, about 230/1, about 240/1, about 250/1, about 260/1, about 270/1, about 280/1, about 290/1 , about 300/1, about 310/1, about 320/1, about 330/1, about 340/1, or about 350/1.

Polymer matrix microspheres containing polydisperse polymer nanospheres can provide, upon polymer removal, metal oxide microspheres having pores that generally have different pore diameters.

Without being limited by theory, it is believed that bulk microsphere samples exhibit rich color with reduced unwanted light scattering when the porosity and/or microsphere diameter and/or pore diameter are within a certain range. The color properties of a bulk sample are important because dyes are used in bulk, such as in paint, inks, coatings, cosmetics, or materials for medical or security use. In some embodiments, white microspheres are desirable, for example for use as white dyes. The porous microspheres contain primarily a metal oxide, that is, they may consist mainly of or consist of a metal oxide. Preferably, the bulk sample of the porous microspheres exhibits a color visible to the human eye. The light absorber may also be present in the microspheres, which may provide a richer observed color. Absorbers include inorganic and organic pigments, for example a broadband absorber such as carbon black. Scavengers can be added, for example, by physically mixing the microspheres and scavengers together, or by including the scavengers in the droplets to be dried. For carbon black, controlled calcination can be used to produce carbon black in situ from polymer degradation. The microsphere of the present invention may have no observable color without added light absorber and exhibit observable color with added light absorber.

The porous microspheres can be used as colorants, for example, for aqueous formulations, oil based formulations, paints, coating formulations, foods, plastics, cosmetic formulations, or materials for medical or safety uses. Coating compositions include, for example, automotive coatings, architectural coatings, varnishes, and the like.

The porous metal oxide microspheres of the present invention may exhibit an angle-dependent color or an angle-independent color. "Angle-dependent" color means that the observed color depends on the angle of incident light on the sample or the angle between the observer and the sample. "Angle-independent" color means that the observed color is practically independent of the angle of incident light on the sample, or the angle between the observer and the sample.

Angle-independent color can be achieved, for example, using polydisperse polymer nanospheres. Angle-independent color can also be achieved when the step of drying the liquid droplets to form the polymer matrix microspheres is performed quickly without allowing the polymer nanospheres to be ordered. An angle dependent color can be achieved when the liquid droplet drying step is performed slowly.

For example, porous microspheres may contain from about 60.0 wt. % (May percent) to about 99.9 wt. % metal oxide and from about 0.1 wt. % to about 40.0 wt. % of one or more light absorbers, based on the total weight of the microspheres.

Also the object of the present invention are polymeric microspheres containing polydisperse polymeric nanospheres, methods for their preparation and compositions containing them. The method includes the formation of an aqueous dispersion of monodisperse polymeric nanoparticles; the formation of at least one other aqueous dispersion of monodisperse polymeric nanoparticles; providing a continuous oil phase; mixing the aqueous dispersions and the oil phase together to form a water-in-oil emulsion; formation of emulsion droplets; and drying the emulsion droplets to provide polymer microspheres containing polydisperse polymer nanospheres; where the average diameters of the monodisperse polymeric nanoparticles of each of the dispersions are different.

Preferably, porous microspheres and polymeric microspheres may be monodispersed.

According to the present invention, particle size is synonymous with particle diameter and is determined, for example, by scanning electron microscopy (SEM) or transmission electron microscopy (TEM). The mean particle size is synonymous with D50, which means that half of the population is above this point and half is below. The particle size refers to the primary particles. Particle size can be measured by laser light scattering techniques, with dispersions or dry powders. Mercury porosimetry analysis was used to characterize the porosity of the microspheres. Mercury porosimetry applies controlled pressure to a sample immersed in mercury. External pressure is applied to penetrate the mercury into the voids/pores of the material. The amount of pressure required to penetrate the voids/pores is inversely proportional to the size of the voids/pores. The mercury porosimeter generates volume and pore size distributions from pressure versus penetration data obtained by the device using the Washburn equation. For example, porous silica microspheres containing voids/pores with an average size of 165 nm have an average porosity of 0.8.

The term "bulk sample" means a population of microspheres. For example, a bulk microsphere sample is simply a bulk population of microspheres, such as ≥0.5 mg, ≥0.7 mg, ≥1.0 mg, ≥2.5 mg, ≥5.0 mg, ≥10.0 mg, or ≥25.0 mg. The bulk sample of microspheres may be substantially free of other components. The term "porous microspheres" may mean a bulk sample.

The phrase "exhibits a color as seen by the human eye" means that the color will be observed by the average person. It can be observed for any bulk sample distributed over any surface area, for example, a bulk sample distributed over a surface area from any of about 1 cm ² , about 2 cm ² , about 3 cm ² , about 4 cm ² , about 5 cm ² or about 6 cm ² to any of about 7 cm ² , about 8 cm ² , about 9 cm ² , about 10 cm ² , about 11 cm 2 , about 12 cm ² , about 13 cm ² , about 14 cm ² , or about ¹⁵ cm ² . It may also mean the possibility of observation by a CIE 1931 2° standard observer and/or a CIE 1964 10° standard observer. The background for viewing the color can be any background, such as a white background, a black background, or a dark background, anything between white and black.

The preposition "from" can mean "containing", for example, "fluid dispersion from" can be interpreted as "fluid dispersion containing". The terms "microspheres", "nanospheres", "droplets", etc., referred to in this document, may mean, for example, a plurality of them, their population, their population, their sample, or their bulk sample.

The term "micro" or "microsize" means from about 0.5 microns to about 999 microns. The term "nano" or "nano" means from about 1 nm to about 999 nm.

The terms "spheres" and "particles" can be used interchangeably.

The term "monodisperse" when applied to a population of microspheres or nanospheres means particles having generally the same shape and generally the same diameter. For example, a monodisperse population of microspheres or nanospheres according to the present invention, for example, may have 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of particles, by number, having a diameter within ±7%, ±6%, ±5%, ±4%, ±3%, ±2% or ±1% of the mean population diameter. The term "monodisperse polymeric nanoparticles" refers to a population of monodisperse polymeric nanoparticles.

The term "polydisperse" in relation to nanospheres means a sample containing a first monodisperse population having a first average diameter and at least a second monodisperse population having a second average diameter, the first and second diameters being different. The polydisperse sample of microspheres contains at least two monodisperse populations and may contain 3, 4, 5, 6, etc. monodisperse populations, each of which has its own average particle size. A polydisperse sample having only the first and second monodisperse polymeric nanospheres is a "bimodal" sample having a bimodal particle size distribution.

The term "essentially free from other components" means, for example, containing ≤5%, ≤4%, ≤3%, ≤2%, ≤1% or ≤0.5 wt. % of other components. Similarly, "substantially none" means little or no.

"Substrate" can mean a water-based or oil-based support or "carrier" and the support can be a minor part or a major part of the final composition. Support can also mean a solid, semi-solid, gel, liquid, paste, cream, etc.

Removal of the monodisperse population of polymeric nanospheres provides porous metal oxide microspheres having a corresponding pore population having an average pore diameter. Removal of more than one monodisperse population of polymeric nanospheres (polydisperse polymeric nanospheres) provides porous metal oxide microspheres having corresponding populations of pores having different mean pore diameters. That is, porous metal oxide microspheres having more than one population of pores, each having an average pore diameter, where each population has a different average pore diameter, and where the average pore diameters are from about 50 nm to about 999 nm.

The diameters of the polymeric nanospheres of the polymeric microspheres and the pore diameters of the porous microspheres can be, for example, bimodal, trimodal, quadrimodal, etc.

The singular herein refers to one or more than one (eg, at least one) grammatical entity. Any ranges given herein are inclusive. The term "about", used throughout, is used to describe and account for small fluctuations. For example, "about" can mean that the numerical value can be changed to ±5%, ±4%, ±3%, ±2%, ±1%, ±0.5%, ±0.4%, ±0, 3%, ±0.2%, ±0.1% or ±0.05%. All numerical values are modified by the term "about", whether explicitly stated or not. Numeric values modified by the term "about" include the specific value indicated. For example, "about 5.0" includes 5.0.

The US patents, US patent applications, and published US patent applications discussed herein are incorporated herein by reference.

Unless otherwise indicated, all parts and percentages are by weight. Mass percent (wt.%), unless otherwise indicated, is given on the basis of the entire composition, without the content of any volatile substances, that is, on the basis of the content of dry solids.

A non-limiting first set of embodiments of the invention directed to methods for making polymeric microspheres include:

According to a first embodiment, a method is disclosed for preparing polymeric microspheres containing polydisperse polymeric nanospheres, the method comprising forming a liquid solution or dispersion of monodisperse polymeric nanoparticles; the formation of at least one additional liquid solution or dispersion of monodisperse polymeric nanoparticles; mixing each of the solutions or dispersions together; the formation of droplets of the mixture; and drying the droplets to provide polymeric microspheres containing polydisperse polymeric nanospheres; where the average diameters of monodisperse polymeric nanoparticles of each of the solutions or dispersions are different.

Droplet drying according to some embodiments may include microwave irradiation, oven drying, vacuum drying, drying in the presence of a desiccant, or a combination thereof.

According to a second embodiment, the method according to embodiment 1 is disclosed, comprising mixing solutions or dispersions together and spray drying the mixture to provide polymeric microspheres. According to a third embodiment, the method according to Embodiment 1 is disclosed, comprising generating liquid droplets using a vibrating nozzle. According to a fourth embodiment, the method according to Embodiments 1 to 3 is disclosed, wherein the liquid droplets are water droplets. According to the fifth embodiment, the method according to Embodiments 1 to 3 is disclosed, wherein the liquid droplets are oil droplets.

According to a sixth embodiment, the method according to embodiment 1 is disclosed, comprising providing a continuous phase and mixing solutions or dispersions with the continuous phase to form an emulsion containing a dispersed liquid solution or dispersed drops.

According to the seventh embodiment, the method according to embodiment 6 is disclosed, comprising providing a continuous oil phase and mixing aqueous solutions or dispersions with the continuous oil phase to form a water-in-oil emulsion containing water droplets. According to an eighth embodiment, the method according to embodiment 6 is disclosed, comprising providing a continuous aqueous phase and mixing oily solutions or dispersions with the continuous phase to form an oil-in-water emulsion containing oil droplets. According to a ninth embodiment, the method according to embodiments 6 to 8 is disclosed, including droplet collection.

According to a tenth embodiment, the method according to embodiment 9 is disclosed, comprising drying droplets to provide polymer microspheres containing polydisperse polymer nanospheres.

According to an eleventh embodiment, the method according to embodiments 6-10 is disclosed, wherein drying the droplets comprises microwave irradiation, oven drying, vacuum drying, drying in the presence of a desiccant, or a combination thereof. According to the twelfth embodiment, the method according to embodiments 7-11 is disclosed, wherein the oil phase or solution or dispersion contains a hydrocarbon, silicon oil, or fluorinated oil. According to a thirteenth embodiment, the method according to Embodiments 6 to 12 is disclosed, wherein droplet formation occurs in a microfluidic device.

According to a fourteenth embodiment, the method according to embodiments 6 to 13 is disclosed, wherein droplet formation occurs in a microfluidic device that comprises a droplet generation unit having a channel width of any of about 10 µm, about 15 µm, about 20 µm, about 25 µm, about 30 µm, about 35 µm, about 40 µm, or about 45 µm to any of about 50 µm, about 55 µm, about 60 µm, about 65 µm, about 70 µm, about 75 µm, about 80 µm, about 85 µm, about 90 µm, about 95 µm or about 100 µm. According to a fifteenth embodiment, the method according to embodiments 13 or 14 is disclosed, comprising collecting drops of emulsion from a microfluidic device.

According to a sixteenth embodiment, a method according to any of the preceding embodiments is disclosed, comprising forming a first liquid solution or dispersion of first monodisperse polymeric nanoparticles and forming a second liquid solution or dispersion of second monodispersed polymeric nanoparticles; for example, where wt./wt. the ratio of the first monodisperse polymeric nanoparticles and the second monodisperse polymeric nanoparticles is from any of about 1/20, about 1/19, about 1/18, about 1/17, about 1/16, about 1/15, about 1/14, about 1/13, about 1/12, about 1/11, about 1/10, about 1/9, about 1/8, about 1/7, about 1/6, about 1/5, about 1/4, about 1/3, about 1/2, or about 1/1 to any of about 2/1, about 3/1, about 4/1, about 5/1, about 6/1, about 7/1, about 8/ 1, about 9/1, about 10/1, about 11/1, about 12/1, about 13/1, about 14/1, about 15/1, about 16/1, about 17/1, about 18/ 1, around 19/1 or around 20/1.

According to a seventeenth embodiment, a method according to any of the preceding embodiments of the present invention is disclosed, wherein the polymeric nanoparticles have an average diameter of any of about 50 nm, about 75 nm, about 100 nm, about 130 nm, about 160 nm, about 190 nm, about 210 nm, about 240 nm, about 270 nm, about 300 nm, about 330 nm, about 360 nm, about 390 nm, about 410 nm, about 440 nm, about 470 nm, about 500 nm, about 530 nm, about 560 nm , about 590 nm or about 620 nm to any of about 650 nm, about 680 nm, about 710 nm, about 740 nm, about 770 nm, about 800 nm, about 830 nm, about 860 nm, about 890 nm, about 910 nm , about 940 nm, about 970 nm, or about 990 nm.

According to an eighteenth embodiment, a process according to any of the preceding embodiments of the present invention is disclosed, wherein the polymers are selected from the group consisting of poly(meth)acrylic acid, poly(meth)acrylates, polystyrenes, polyacrylamides, polyethylene, polypropylene, polylactic acid, polyacrylonitrile, their derivatives, their salts, their copolymers and combinations thereof. According to a nineteenth embodiment, a method according to any of the preceding embodiments of the present invention is disclosed, wherein the polymers are selected from the group consisting of polystyrenes, for example, polystyrene copolymers such as polystyrene/acrylic acid, polystyrene/poly(ethylene glycol)methacrylate, or polystyrene/styrenesulfonate.

According to a twentieth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the microspheres have an average diameter of about 0.5 µm to about 100 µm. According to a twenty-first embodiment, a method according to any of the preceding embodiments is disclosed, wherein the microspheres have an average diameter of from about 1 µm to about 75 µm, about 2 µm to about 70 µm, from about 3 µm to about 65 µm, from about 4 µm to about 60 µm, about 5 µm to about 55 µm, or about 5 µm to about 50 µm; for example, from any of about 5 µm, about 6 µm, about 7 µm, about 8 µm, about 9 µm, about 10 µm, about 11 µm, about 12 µm, about 13 µm, about 14 µm, or about 15 µm to any of about 16 µm, about 17 µm, about 18 µm, about 19 µm, about 20 µm, about 21 µm, about 22 µm, about 23 µm, about 24 µm, or about 25 µm. According to a twenty-second embodiment, a method according to any of the preceding embodiments is disclosed, wherein the microspheres have an average diameter of any of about 4.5 µm, about 4.8 µm, about 5.1 µm, about 5.4 µm, about 5.7 µm, about 6.0 µm, about 6.3 µm, about 6.6 µm, about 6.9 µm, about 7.2 µm, or about 7.5 µm to any of about 7.8 µm, about 8.1 µm , about 8.4 µm, about 8.7 µm, about 9.0 µm, about 9.3 µm, about 9.6 µm, or about 9.9 µm.

According to a twenty-third embodiment, a method according to any of the preceding embodiments is disclosed, wherein the bulk sample of polymeric microspheres exhibits a color visible to the human eye. According to a twenty-fourth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the bulk sample of polymeric microspheres exhibits an angle dependent color as seen by the human eye. According to a twenty-fifth embodiment, a method according to any one of Embodiments 1-23 is disclosed, wherein the bulk sample of polymeric microspheres exhibits an angle-dependent color as seen by the human eye.

According to a twenty-sixth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the microspheres are monodispersed. According to a twenty-seventh embodiment, a method according to any of the preceding embodiments is disclosed, wherein the polymeric microspheres are a bulk sample of the microspheres.

According to a twenty-eighth embodiment, a method according to any of the preceding embodiments is disclosed, comprising adding a metal oxide to one or more liquid solutions or dispersions; or adding metal oxide to the mixture.

According to a twenty-ninth embodiment, polymeric microspheres are disclosed, obtained according to any of the preceding methods. According to a thirtieth embodiment, a bulk sample of polymeric microspheres prepared according to any of the preceding methods is disclosed.

A non-limiting second set of embodiments of the present invention directed to polymeric microspheres include:

Polymeric microspheres containing more than one population of monodisperse polymeric nanospheres, where each population of monodisperse polymeric nanospheres has different average diameters.

According to a second embodiment, polymeric microspheres according to embodiment 1 are disclosed, comprising a first population of monodisperse polymeric nanoparticles and a second population of monodisperse polymeric nanoparticles; for example, where wt./wt. the ratio of the first population of polymeric nanospheres and the second population of polymeric nanospheres is from any of about 1/20, about 1/19, about 1/18, about 1/17, about 1/16, about 1/15, about 1/14, about 1/13, about 1/12, about 1/11, about 1/10, about 1/9, about 1/8, about 1/7, about 1/6, about 1/5, about 1/4, about 1/3, about 1/2, or about 1/1 to any of about 2/1, about 3/1, about 4/1, about 5/1, about 6/1, about 7/1, about 8/ 1, about 9/1, about 10/1, about 11/1, about 12/1, about 13/1, about 14/1, about 15/1, about 16/1, about 17/1, about 18/ 1, around 19/1 or around 20/1.

According to a third embodiment, polymeric microspheres according to embodiments 1 or 2 are disclosed, wherein the polymeric nanospheres have an average diameter of any of about 100 nm, about 130 nm, about 160 nm, about 190 nm, about 210 nm, about 240 nm, about 270 nm , about 300 nm, about 330 nm, about 360 nm, about 390 nm, about 410 nm, about 440 nm, about 470 nm, about 500 nm, about 530 nm, about 560 nm, about 590 nm or about 620 nm to any of about 650 nm, about 680 nm, about 710 nm, about 740 nm, about 770 nm, about 800 nm, about 830 nm, about 860 nm, about 890 nm, about 910 nm, about 940 nm, or about 970 nm.

According to a fourth embodiment, polymer microspheres are disclosed according to any of the preceding embodiments wherein the polymers are selected from the group consisting of poly(meth)acrylic acid, poly(meth)acrylates, polystyrenes, polyacrylamides, polyethylene, polypropylene, polylactic acid, polyacrylonitrile, their derivatives, their salts, their copolymers and combinations thereof.

According to a fifth embodiment, polymeric microspheres according to any of the preceding embodiments are disclosed, wherein the polymers are selected from the group consisting of polystyrenes, for example, polystyrene copolymers such as polystyrene/acrylic acid, polystyrene/poly(ethylene glycol)methacrylate, or polystyrene/styrenesulfonate.

According to a sixth embodiment, polymer microspheres according to any of the preceding embodiments are disclosed, wherein the polymers of each population of polymer nanospheres are identical. According to a seventh embodiment, polymer microspheres are disclosed according to any one of Embodiments 1-5, wherein the polymers of each population of polymer nanospheres are different.

According to an eighth embodiment, polymeric microspheres according to any of the preceding embodiments are disclosed, wherein the microspheres have an average diameter of about 0.5 µm to about 100 µm. According to a ninth embodiment, polymeric microspheres according to any of the preceding embodiments are disclosed, wherein the microspheres have an average diameter of from about 1 µm to about 75 µm, about 2 µm to about 70 µm, from about 3 µm to about 65 µm, from about 4 µm to about 60 µm, about 5 µm to about 55 µm, or about 5 µm to about 50 µm; for example, from any of about 5 µm, about 6 µm, about 7 µm, about 8 µm, about 9 µm, about 10 µm, about 11 µm, about 12 µm, about 13 µm, about 14 µm, or about 15 µm to any of about 16 µm, about 17 µm, about 18 µm, about 19 µm, about 20 µm, about 21 µm, about 22 µm, about 23 µm, about 24 µm, or about 25 µm. According to a tenth embodiment, polymer microspheres according to any of the preceding embodiments are disclosed, wherein the microspheres have an average diameter of any of about 4.5 µm, about 4.8 µm, about 5.1 µm, about 5.4 µm, about 5.7 µm, about 6.0 µm, about 6.3 µm, about 6.6 µm, about 6.9 µm, about 7.2 µm, or about 7.5 µm to any of about 7.8 µm about 8.1 µm, about 8.4 µm, about 8.7 µm, about 9.0 µm, about 9.3 µm, about 9.6 µm, or about 9.9 µm.

According to a twelfth embodiment, polymeric microspheres according to any of the preceding embodiments are disclosed, wherein the bulk sample of polymeric microspheres exhibits a color visible to the human eye. According to a thirteenth embodiment, polymeric microspheres according to any of the preceding embodiments are disclosed, wherein the bulk sample of polymeric microspheres exhibits an angle dependent color as seen by the human eye. According to a fourteenth embodiment, polymeric microspheres are disclosed according to any one of Embodiments 1-12, wherein a bulk sample of polymeric microspheres exhibits an angle dependent color as seen by the human eye.

According to a fifteenth embodiment, polymeric microspheres are disclosed according to any of the preceding embodiments, which are monodispersed.

According to a sixteenth embodiment, polymeric microspheres according to any of the preceding embodiments are disclosed, further comprising a metal oxide.

A non-limiting third set of embodiments of the present invention directed to methods for producing porous metal oxide microspheres include:

According to a first embodiment, a method for producing porous metal oxide microspheres is disclosed, the method comprising forming a liquid solution or dispersion of monodisperse polymeric nanoparticles; the formation of at least one additional liquid solution or dispersion of monodisperse polymeric nanoparticles; mixing each of the solutions or dispersions together; where the metal oxide is added to one or more of the solutions or suspensions and/or where the metal oxide is added to the mixture to form a liquid dispersion containing polymeric nanoparticles and metal oxide; formation of liquid droplets of the liquid dispersion; drying drops to provide polymer matrix microspheres containing polydisperse polymer nanospheres and metal oxide; and removing the polymeric nanospheres from the matrix microspheres to provide porous metal oxide microspheres; where the average diameters of monodisperse polymeric nanoparticles of each of the solutions or dispersions are different.

According to a second embodiment, a method according to Embodiment 1 is disclosed, comprising mixing solutions or dispersions together and spray drying the mixture to form polymer matrix microspheres, and removing polymer nanospheres from the matrix microspheres.

According to a third embodiment, the method according to Embodiment 1 is disclosed, comprising generating liquid droplets using a vibrating nozzle. According to a fourth embodiment, the method according to Embodiments 1 to 3 is disclosed, wherein the liquid droplets are water droplets. According to a fifth embodiment, the method according to Embodiments 1 to 3 is disclosed, wherein the liquid droplets are oil droplets.

According to a sixth embodiment, the method of Embodiment 1 is disclosed, comprising providing a continuous phase and mixing a liquid dispersion with the continuous phase to form an emulsion containing dispersed liquid droplets of the dispersion. According to the seventh embodiment, the method according to embodiment 6 is disclosed, comprising providing a continuous oil phase and mixing an aqueous dispersion with a continuous oil phase to form a water-in-oil emulsion containing water droplets.

According to an eighth embodiment, the method of Embodiment 6 is disclosed, comprising providing a continuous aqueous phase and mixing an oil phase with the continuous phase to form an oil-in-water emulsion containing oil droplets. According to a ninth embodiment, the method according to embodiments 6 to 8 is disclosed, including droplet collection. According to a tenth embodiment, the method according to embodiment 9 is disclosed, comprising drying droplets to provide polymer matrix microspheres containing polydisperse polymer nanospheres.

According to an eleventh embodiment, the method according to embodiments 6-10 is disclosed, wherein drying the droplets comprises microwave irradiation, oven drying, vacuum drying, drying in the presence of a desiccant, or a combination thereof.

According to the twelfth embodiment, the method according to embodiments 7-11 is disclosed, wherein the oil phase or solution or dispersion contains a hydrocarbon, silicon oil, or fluorinated oil.

According to a thirteenth embodiment, the method according to Embodiments 6 to 12 is disclosed, wherein droplet formation occurs in a microfluidic device. According to a fourteenth embodiment, the method according to embodiments 6-3 is disclosed, wherein droplet formation occurs in a microfluidic device that comprises a droplet generation unit having a channel width of any of about 10 µm, about 15 µm, about 20 µm, about 25 µm, about 30 µm, about 35 µm, about 40 µm, or about 45 µm to any of about 50 µm, about 55 µm, about 60 µm, about 65 µm, about 70 µm, about 75 µm, about 80 µm, about 85 µm, about 90 µm, about 95 µm or about 100 µm. According to a fifteenth embodiment, a method according to embodiments 13 or 14 is disclosed, comprising collecting droplets from a microfluidic device.

According to a sixteenth embodiment, a method according to any of the preceding embodiments is disclosed, comprising forming a first liquid solution or dispersion of first monodisperse polymeric nanoparticles and forming a second liquid solution or dispersion of second monodispersed polymeric nanoparticles; for example, where wt./wt. the ratio of the first monodisperse polymeric nanoparticles and the second monodisperse polymeric nanoparticles is from any of about 1/20, about 1/19, about 1/18, about 1/17, about 1/16, about 1/15, about 1/14, about 1/13, about 1/12, about 1/11, about 1/10, about 1/9, about 1/8, about 1/7, about 1/6, about 1/5, about 1/4, about 1/3, about 1/2, or about 1/1 to any of about 2/1, about 3/1, about 4/1, about 5/1, about 6/1, about 7/1, about 8/ 1, about 9/1, about 10/1, about 11/1, about 12/1, about 13/1, about 14/1, about 15/1, about 16/1, about 17/1, about 18/ 1, around 19/1 or around 20/1.

According to a seventeenth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the polymeric nanoparticles have an average diameter of any of about 50 nm, about 75 nm, about 100 nm, about 130 nm, about 160 nm, about 190 nm, about 210 nm , about 240 nm, about 270 nm, about 300 nm, about 330 nm, about 360 nm, about 390 nm, about 410 nm, about 440 nm, about 470 nm, about 500 nm, about 530 nm, about 560 nm, about 590 nm or about 620 nm to any of about 650 nm, about 680 nm, about 710 nm, about 740 nm, about 770 nm, about 800 nm, about 830 nm, about 860 nm, about 890 nm, about 910 nm, about 940 nm, about 970 nm or about 990 nm.

According to an eighteenth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the polymer is selected from the group consisting of poly(meth)acrylic acid, poly(meth)acrylates, polystyrenes, polyacrylamides, polyethylene, polypropylene, polylactic acid, polyacrylonitrile, derivatives thereof. , their salts, their copolymers, and combinations thereof. According to a nineteenth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the polymer is selected from the group consisting of polystyrenes, for example, polystyrene copolymers such as polystyrene/acrylic acid, polystyrene/poly(ethylene glycol)methacrylate, or polystyrene/styrenesulfonate.

According to a twentieth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the metal oxide is one or more of silicon oxide, titanium oxide, alumina, zirconium oxide, cerium oxide, iron oxides, zinc oxide, indium oxide, tin oxide, or chromium oxide.

According to the twenty-first embodiment, a method is disclosed according to any of the preceding embodiments, in which wt./wt. the ratio of polymer nanoparticles in general and metal oxide is from any of about 0.1/1, 0.5/1, about 1.0/1, about 1.5/1, about 2.0/1, about 2.5 /1 or about 3.0/1 to any of about 3.5/1, about 4.0/1, about 5.0/1, about 5.5/1, about 6.0/1, about 6, 5/1, about 7.0/1, about 8.0/1, about 9.0/1, or about 10.0/1.

According to a twenty-second embodiment, a method according to any of the preceding embodiments is disclosed, wherein drying the droplets comprises microwave irradiation, oven drying, vacuum drying, drying in the presence of a desiccant, or a combination thereof.

According to a twenty-third embodiment, a method according to any of the preceding embodiments is disclosed, wherein the removal of the polymeric nanospheres comprises calcining the matrix microspheres at temperatures from any of about 200°C, about 350°C, from about 400°C, from about 450°C, about 500°C or about 550°C to any of about 600°C, about 650°C, about 700°C or about 1200°C for a period from any of about OD h (hour), 1 h, about 1, 5 hours, about 2.0 hours, about 2.5 hours, about 3.0 hours, about 3.5 hours, or about 4.0 hours to any of about 4.5 hours, about 5.0 hours, about 5, 5 hours, about 6.0 hours, about 6.5 hours, about 7.0 hours, about 7.5 hours, about 8.0 hours, or about 12 hours. Alternatively, the calcination may be carried out at temperatures of at least about 200° C. , at least about 500°C, or at least about 1000°C, for a suitable period, for example, for at least about 0.1 hour, at least about 1 hour, at least about 5 hours, or at least about 10 hours.

According to a twenty-fourth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres have an average diameter of about 0.5 µm to about 100 µm and an average porosity of about 0.10 to about 0.90, or about 0.10 up to about 0.80; where the porous microspheres have more than one population of pores, each having an average pore diameter, where each population has a different average pore diameter; and where the average pore diameters are from about 50 nm to about 999 nm; for example, where the porous microspheres have a first population of pores having an average pore diameter of from about 50 nm to about 999 nm and a second population of pores having an average pore diameter of from about 50 nm to about 999 nm, where the first and second average pore diameters are different .

According to a twenty-fifth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres have an average diameter of from about 1 µm to about 75 µm, about 2 µm to about 70 µm, from about 3 µm to about 65 µm, from about 4 µm to about 60 µm, from about 5 µm to about 55 µm, or from about 5 µm to about 50 µm; for example, from any of about 5 µm, about 6 µm, about 7 µm, about 8 µm, about 9 µm, about 10 µm, about 11 µm, about 12 µm, about 13 µm, about 14 µm, or about 15 µm to any of about 16 µm, about 17 µm, about 18 µm, about 19 µm, about 20 µm, about 21 µm, about 22 µm, about 23 µm, about 24 µm, or about 25 µm.

According to a twenty-sixth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres have an average porosity of any of about 0.10, about 0.12, about 0.14, about 0.16, about 0.18, about 0.20, about 0.22, about 0.24, about 0.26, about 0.28, about 0.30, about 0.32, about 0.34, about 0.36, about 0.38, about 0.40, about 0.42, about 0.44, about 0.46, about 0.48 about 0.50, about 0.52, about 0.54, about 0.56, about 0.58 or about 0 .60 to any of about 0.62, about 0.64, about 0.66, about 0.68, about 0.70, about 0.72, about 0.74, about 0.76, about 0.78, about 0.80 or about 0.90.

According to a twenty-seventh embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres have an average pore diameter of any of about 50 nm, about 60 nm, about 70 nm, about 80 nm, about 100 nm, about 120 nm, about 140 approx. 160 nm, approx. 180 nm, approx. 200 nm, approx. 220 nm, approx. 240 nm, approx. 260 nm, approx. 280 nm, approx. 300 nm, approx. about 400 nm, about 420 nm, or about 440 nm to any of about 460 nm, about 480 nm, about 500 nm, about 520 nm, about 540 nm, about 560 nm, about 580 nm, about 600 nm, about 620 nm, about 640 nm, about 660 nm, about 680 nm, about 700 nm, about 720 nm, about 740 nm, about 760 nm, about 780 nm or about 800 nm.

According to a twenty-eighth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres have an average diameter of any of about 4.5 µm, about 4.8 µm, about 5.1 µm, about 5.4 µm, about 5. 7 µm, about 6.0 µm, about 6.3 µm, about 6.6 µm, about 6.9 µm, about 7.2 µm or about 7.5 µm to any of about 7.8 µm about 8.1 µm, about 8.4 µm, about 8.7 µm, about 9.0 µm, about 9.3 µm, about 9.6 µm, or about 9.9 µm.

According to a twenty-ninth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres have an average porosity of any of about 0.45, about 0.47, about 0.49, about 0.51, about 0.53, about 0.55 or about 0.57 to any of about 0.59, about 0.61, about 0.63, or about 0.65.

According to a thirtieth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres have an average pore diameter of any of about 220 nm, about 225 nm, about 230 nm, about 235 nm, about 240 nm, about 245 nm, or about 250 nm to any of about 255 nm, about 260 nm, about 265 nm, about 270 nm, about 275 nm, about 280 nm, about 285 nm, about 290 nm, about 295 nm, or about 300 nm.

According to a thirty-first embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres have an average diameter of any of about 4.5 µm, about 4.8 µm, about 5.1 µm, about 5.4 µm, about 5. 7 µm, about 6.0 µm, about 6.3 µm, about 6.6 µm, about 6.9 µm, about 7.2 µm or about 7.5 µm to any of about 7.8 µm about 8.1 µm, about 8.4 µm, about 8.7 µm, about 9.0 µm, about 9.3 µm, about 9.6 µm, or about 9.9 µm; average porosity from any of about 0.45, about 0.47, about 0.49, about 0.51, about 0.53, about 0.55, or about 0.57 to any of about 0.59, about 0, 61, about 0.63 or about 0.65; and an average pore diameter from any of about 220 nm, about 225 nm, about 230 nm, about 235 nm, about 240 nm, about 245 nm, or about 250 nm to any of about 255 nm, about 260 nm, about 265 nm, about 270 nm, about 275 nm, about 280 nm, about 285 nm, about 290 nm, about 295 nm, or about 300 nm.

According to the thirty-second variant of implementation discloses a method according to any of the previous embodiments, where the porous microspheres contain from about 60.0 wt. % to about 99.9 wt. % metal oxide, for example, containing from any of about 60.0 wt. %, about 64.0 wt. %, about 67.0 wt. %, about 70.0 wt. %, about 73.0 wt. %, about 76.0 wt. %, about 79.0 wt. %, about 82.0 wt. % or about 85.0 wt. % to any of about 88.0 wt. %, about 91.0 wt. %, about 94.0 wt. %, about 97.0 wt. %, about 98.0 wt. %, about 99.0 wt. % or about 99.9 wt. % metal oxide, based on the total weight of the microspheres.

According to the thirty-third variant of implementation discloses a method according to any of the previous embodiments, where the porous microspheres contain from about 0.1 wt. % to about 40.0 wt. % of one or more light absorbers, for example, contain from any of about 0.1 wt. %, about 0.3 wt. %, about 0.5 wt. %, about 0.7 wt. %, about 0.9 wt. %, about 1.0 wt. %, about 1.5 wt. %, about 2.0 wt. %, about 2.5 wt. %, about 5.0 wt. %, about 7.5 wt. %, about 10.0 wt. %, about 13.0 wt. %, about 17.0 wt. %, about 20.0 wt. % or about 22.0 wt. % to any of about 24.0 wt. %, about 27.0 wt. %, about 29.0 wt. %, about 31.0 wt. %, about 33.0 wt. %, about 35.0 wt. %, about 37.0 wt. %, about 39.0 wt. % or about 40.0 wt. % of one or more light absorbers, based on the total weight of the microspheres. According to a thirty-fourth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous microspheres comprise one or more light absorbers selected from the group consisting of inorganic and organic pigments, such as carbon black.

According to a thirty-fifth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the bulk sample of the porous microspheres exhibits a color as seen by the human eye. According to a thirty-sixth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the bulk sample of porous microspheres exhibits an angle-independent color as seen by the human eye. According to a thirty-seventh embodiment, a method according to any one of Embodiments 1-35 is disclosed, wherein the bulk sample of porous microspheres exhibits an angle-dependent color as seen by the human eye.

According to a thirty-eighth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the microspheres are monodispersed. According to a thirty-ninth embodiment, a method according to any of the preceding embodiments is disclosed, wherein the porous metal oxide microspheres are a bulk microsphere pattern.

According to the fortieth embodiment, porous microspheres obtained according to any of the preceding methods are disclosed. According to a forty-first embodiment, a bulk sample of microspheres obtained according to any of the preceding methods is disclosed.

A non-limiting fourth set of embodiments of the present invention directed to porous metal oxide microspheres include:

According to a first embodiment, porous metal oxide-containing microspheres are disclosed, wherein the microspheres have an average diameter of about 0.5 µm to about 100 µm and an average porosity of about 0.10 to about 0.80; where the porous microspheres have more than one population of pores, each having an average pore diameter, where each population has a different average pore diameter; and where the average pore diameters are from about 50 nm to about 999 nm; for example, where the microspheres have a first population of pores having an average pore diameter of from about 50 nm to about 999 nm, and a second population of pores having an average pore diameter of from about 50 nm to about 999 nm, where the first and second average pore diameters are different.

In a second embodiment, the porous microspheres of Embodiment 1 are disclosed which have an average diameter of about 1 µm to about 75 µm, about 2 µm to about 70 µm, about 3 µm to about 65 µm, about 4 µm to about 60 µm. , from about 5 µm to about 55 µm, or from about 5 µm to about 50 µm; for example, from any of about 5 µm, about 6 µm, about 7 µm, about 8 µm, about 9 µm, about 10 µm, about 11 µm, about 12 µm, about 13 µm, about 14 µm, or about 15 µm to any of about 16 µm, about 17 µm, about 18 µm, about 19 µm, about 20 µm, about 21 µm, about 22 µm, about 23 µm, about 24 µm, or about 25 µm.

According to a third embodiment, porous microspheres according to embodiments 1 or 2 are disclosed that have an average porosity of any of about 0.10, about 0.12, about 0.14, about 0.16, about 0.18, about 0.20 , about 0.22, about 0.24, about 0.26, about 0.28, about 0.30, about 0.32, about 0.34, about 0.36, about 0.38, about 0.40, about 0.42, about 0.44, about 0.46, about 0.48 about 0.50, about 0.52, about 0.54, about 0.56, about 0.58, or about 0.60 to any of about 0.62, about 0.64, about 0 .66, about 0.68, about 0.70, about 0.72, about 0.74, about 0.76, about 0.78, about 0.80, or about 0.90.

According to a fourth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the average pore diameters are from any of about 50 nm, about 60 nm, about 70 nm, about 80 nm, about 100 nm, about 120 nm, about 140 nm, approx. 160 nm, approx. 180 nm, approx. 200 nm, approx. 220 nm, approx. 240 nm, approx. 260 nm, approx. 280 nm, approx. 300 nm, approx. 320 nm, approx. nm, about 420 nm or about 440 nm to any of about 460 nm, about 480 nm, about 500 nm, about 520 nm, about 540 nm, about 560 nm, about 580 nm, about 600 nm, about 620 nm, about 640 nm, about 660 nm, about 680 nm, about 700 nm, about 720 nm, about 740 nm, about 760 nm, about 780 nm or about 800 nm.

According to a fifth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, which have an average diameter of any of about 4.5 µm, about 4.8 µm, about 5.1 µm, about 5.4 µm, about 5.7 µm , about 6.0 µm, about 6.3 µm, about 6.6 µm, about 6.9 µm, about 7.2 µm, or about 7.5 µm to any of about 7.8 µm, about 8.1 µm, about 8.4 µm, about 8.7 µm, about 9.0 µm, about 9.3 µm, about 9.6 µm, or about 9.9 µm.

According to a sixth embodiment, porous microspheres are disclosed according to any of the preceding embodiments, which have an average porosity of any of about 0.45, about 0.47, about 0.49, about 0.51, about 0.53, about 0.55 or about 0.57 to any of about 0.59, about 0.61, about 0.63, or about 0.65.

According to a seventh embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the average pore diameters are from any of about 220 nm, about 225 nm, about 230 nm, about 235 nm, about 240 nm, about 245 nm, or about 250 nm to any of about 255 nm, about 260 nm, about 265 nm, about 270 nm, about 275 nm, about 280 nm, about 285 nm, about 290 nm, about 295 nm, or about 300 nm.

According to an eighth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, which have an average diameter of any of about 4.5 µm, about 4.8 µm, about 5.1 µm, about 5.4 µm, about 5.7 µm , about 6.0 µm, about 6.3 µm, about 6.6 µm, about 6.9 µm, about 7.2 µm, or about 7.5 µm to any of about 7.8 µm, about 8.1 µm, about 8.4 µm, about 8.7 µm, about 9.0 µm, about 9.3 µm, about 9.6 µm, or about 9.9 µm; and which have an average porosity from any of about 0.45, about 0.47, about 0.49, about 0.51, about 0.53, about 0.55, or about 0.57 to any of about 0.59, about 0.61, about 0.63, or about 0.65; and which have average pore diameters from any of about 220 nm, about 225 nm, about 230 nm, about 235 nm, about 240 nm, about 245 nm, or about 250 nm to any of about 255 nm, about 260 nm, about 265 nm , about 270 nm, about 275 nm, about 280 nm, about 285 nm, about 290 nm, about 295 nm, or about 300 nm.

According to a ninth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, containing from about 60.0 wt. % to about 99.9 wt. % metal oxide, for example containing from any of about 60.0 wt. %, about 64.0 wt. %, about 67.0 wt. %, about 70.0 wt. %, about 73.0 wt. %, about 76.0 wt. %, about 79.0 wt. %, about 82.0 wt. % or about 85.0 wt. % to any of about 88.0 wt. %, about 91.0 wt. %, about 94.0 wt. %, about 97.0 wt. %, about 98.0 wt. %, about 99.0 wt. % or about 99.9 wt. % metal oxide, based on the total weight of the microspheres.

According to a tenth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the metal oxide is selected from the group consisting of silicon oxide, titanium oxide, alumina, zirconium oxide, cerium oxide, iron oxides, zinc oxide, indium oxide, tin oxide, chromium oxide and combinations thereof. According to an eleventh embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the metal oxide is selected from the group consisting of silicon oxide, titanium oxide, alumina, and combinations thereof.

According to the twelfth embodiment, porous microspheres are disclosed according to any of the preceding embodiments, containing from about 0.1 wt. % to about 40.0 wt. % of one or more light absorbers, for example containing from any of about 0.1 wt. %, about 0.3 wt. %, about 0.5 wt. %, about 0.7 wt. %, about 0.9 wt. %, about 1.0 wt. %, about 1.5 wt. %, about 2.0 wt. %, about 2.5 wt. %, about 5.0 wt. %, about 7.5 wt. %, about 10.0 wt. %, about 13.0 wt. %, about 17.0 wt. %, about 20.0 wt. % or about 22.0 wt. % to any of about 24.0 wt. %, about 27.0 wt. %, about 29.0 wt. %, about 31.0 wt. %, about 33.0 wt. %, about 35.0 wt. %, about 37.0 wt. %, about 39.0 wt. % or about 40.0 wt. % of one or more light absorbers, based on the total weight of the microspheres. According to a thirteenth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, containing one or more light absorbers selected from the group consisting of inorganic and organic pigments, for example, carbon black.

According to a fifteenth embodiment, the porous microspheres according to any of the preceding embodiments are disclosed, wherein the bulk sample of the porous microspheres exhibits a color visible to the human eye. According to a fifteenth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the bulk sample of porous microspheres exhibits an angle-independent color as seen by the human eye. According to a sixteenth embodiment, porous microspheres according to any one of Embodiments 1-14 are disclosed, wherein a bulk sample of porous microspheres exhibits an angle dependent color as seen by the human eye.

According to a seventeenth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the microspheres are monodisperse.

According to an eighteenth embodiment, a composition is disclosed comprising a support and porous microspheres according to any of the preceding embodiments. According to the nineteenth embodiment, the composition according to embodiment 18 is disclosed, which is an aqueous composition, an oil-based composition, a coating composition, a food product, a paint, a plastic, a cosmetic composition, or a material for medical or safety use.

A non-limiting fifth set of embodiments of the present invention directed to metal oxide microspheres include:

According to a first embodiment, porous microspheres containing a metal oxide are disclosed, wherein a bulk sample of the porous microspheres exhibits a color observed by the human eye; where the porous microspheres have more than one population of pores, each having an average pore diameter, where each population has a different average pore diameter.

In a second embodiment, the porous microspheres of Embodiment 1 are disclosed, wherein the microspheres have an average diameter of about 0.5 µm to about 100 µm and an average porosity of about 0.10 to about 0.90, or about 0.10 to about 0.80; where the porous microspheres have more than one population of pores, each population having an average pore diameter, where each population has a different average pore diameter; and where the average pore diameters are from about 50 nm to about 999 nm; for example, where the microspheres have a first population of pores having an average pore diameter of from about 50 nm to about 999 nm, and a second population of pores having an average pore diameter of from about 50 nm to about 999 nm, where the first and second average pore diameters are different.

According to a third embodiment, porous microspheres according to embodiments 1 or 2 are disclosed, which have an average diameter of from about 1 µm to about 75 µm, about 2 µm to about 70 µm, from about 3 µm to about 65 µm, from about 4 µm to about 60 µm, about 5 µm to about 55 µm, or about 5 µm to about 50 µm; for example, from any of about 5 µm, about 6 µm, about 7 µm, about 8 µm, about 9 µm, about 10 µm, about 11 µm, about 12 µm, about 13 µm, about 14 µm, or about 15 µm to any of about 16 µm, about 17 µm, about 18 µm, about 19 µm, about 20 µm, about 21 µm, about 22 µm, about 23 µm, about 24 µm, or about 25 µm.

According to a fourth embodiment, porous microspheres are disclosed according to any of the preceding embodiments, which have an average porosity of any of about 0.10, about 0.12, about 0.14, about 0.16, about 0.18, about 0.20 , about 0.22, about 0.24, about 0.26, about 0.28, about 0.30, about 0.32, about 0.34, about 0.36, about 0.38, about 0.40 , about 0.42, about 0.44, about 0.46, about 0.48 about 0.50, about 0.52, about 0.54, about 0.56, about 0.58 or about 0.60 to any of about 0.62, about 0.64, about 0.66, about 0.68, about 0.70, about 0.72, about 0.74, about 0.76, about 0.78, about 0, 80 or about 0.90.

According to a fifth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, which have average pore diameters from any of about 50 nm, about 60 nm, about 70 nm, about 80 nm, about 100 nm, about 120 nm, about 140 nm, approx. 160 nm, approx. 180 nm, approx. 200 nm, approx. 220 nm, approx. 240 nm, approx. 260 nm, approx. 280 nm, approx. 300 nm, approx. 320 nm, approx. nm, about 420 nm or about 440 nm to any of about 460 nm, about 480 nm, about 500 nm, about 520 nm, about 540 nm, about 560 nm, about 580 nm, about 600 nm, about 620 nm, about 640 nm, about 660 nm, about 680 nm, about 700 nm, about 720 nm, about 740 nm, about 760 nm, about 780 nm or about 800 nm.

According to a sixth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, which have an average diameter of any of about 4.5 µm, about 4.8 µm, about 5.1 µm, about 5.4 µm, about 5.7 µm , about 6.0 µm, about 6.3 µm, about 6.6 µm, about 6.9 µm, about 7.2 µm, or about 7.5 µm to any of about 7.8 µm, about 8.1 µm, about 8.4 µm, about 8.7 µm, about 9.0 µm, about 9.3 µm, about 9.6 µm, or about 9.9 µm.

According to a seventh embodiment, porous microspheres according to any of the preceding embodiments are disclosed, which have an average porosity of any of about 0.45, about 0.47, about 0.49, about 0.51, about 0.53, about 0.55 or about 0.57 to any of about 0.59, about 0.61, about 0.63, or about 0.65.

According to an eighth embodiment, porous microspheres according to any of the preceding embodiments are disclosed that have average pore diameters from any of about 220 nm, about 225 nm, about 230 nm, about 235 nm, about 240 nm, about 245 nm, or about 250 nm to any of about 255 nm, about 260 nm, about 265 nm, about 270 nm, about 275 nm, about 280 nm, about 285 nm, about 290 nm, about 295 nm, or about 300 nm.

According to a ninth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, which have an average diameter of any of about 4.5 µm, about 4.8 µm, about 5.1 µm, about 5.4 µm, about 5.7 µm , about 6.0 µm, about 6.3 µm, about 6.6 µm, about 6.9 µm, about 7.2 µm, or about 7.5 µm to any of about 7.8 µm, about 8.1 µm, about 8.4 µm, about 8.7 µm, about 9.0 µm, about 9.3 µm, about 9.6 µm, or about 9.9 µm; and which have an average porosity from any of about 0.45, about 0.47, about 0.49, about 0.51, about 0.53, about 0.55, or about 0.57 to any of about 0.59, about 0.61, about 0.63, or about 0.65; and which have average pore diameters from any of about 220 nm, about 225 nm, about 230 nm, about 235 nm, about 240 nm, about 245 nm, or about 250 nm to any of about 255 nm, about 260 nm, about 265 nm , about 270 nm, about 275 nm, about 280 nm, about 285 nm, about 290 nm, about 295 nm, or about 300 nm.

According to the tenth embodiment, porous microspheres are disclosed according to any of the preceding embodiments, containing from about 60.0 wt. % to about 99.9 wt. % metal oxide, for example containing from any of about 60.0 wt. %, about 64.0 wt. %, about 67.0 wt. %, about 70.0 wt. %, about 73.0 wt. %, about 76.0 wt. %, about 79.0 wt. %, about 82.0 wt. % or about 85.0 wt. % to any of about 88.0 wt. %, about 91.0 wt. %, about 94.0 wt. %, about 97.0 wt. %, about 98.0 wt. %, about 99.0 wt. % or about 99.9 wt. % metal oxide, based on the total weight of the microspheres.

According to an eleventh embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the metal oxide is selected from the group consisting of silicon oxide, titanium oxide, alumina, zirconium oxide, cerium oxide, iron oxides, zinc oxide, indium oxide, tin oxide, chromium oxide and combinations thereof. According to a twelfth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the metal oxide is selected from the group consisting of silicon oxide, titanium oxide, alumina, and combinations thereof.

According to the thirteenth embodiment, porous microspheres are disclosed according to any of the preceding embodiments, containing about 0.1 wt. % to about 40.0 wt. % of one or more light absorbers, for example, containing from any of about 0.1 wt. %, about 0.3 wt. %, about 0.5 wt. %, about 0.7 wt. %, about 0.9 wt. %, about 1.0 wt. %, about 1.5 wt. %, about 2.0 wt. %, about 2.5 wt. %, about 5.0 wt. %, about 7.5 wt. %, about 10.0 wt. %, about 13.0 wt. %, about 17.0 wt. %, about 20.0 wt. % or about 22.0 wt. % to any of about 24.0 wt. %, about 27.0 wt. %, about 29.0 wt. %, about 31.0 wt. %, about 33.0 wt. %, about 35.0 wt. %, about 37.0 wt. %, about 39.0 wt. % or about 40.0 wt. % of one or more light absorbers, based on the total weight of the microspheres. According to a fourteenth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, containing one or more light absorbers selected from the group consisting of inorganic and organic pigments, eg carbon black.

According to a fifteenth embodiment, the porous microspheres according to any of the preceding embodiments are disclosed, wherein the bulk sample of the porous microspheres exhibits a color visible to the human eye.

According to a sixteenth embodiment, porous microspheres according to any of the preceding embodiments are disclosed, wherein the microspheres are monodisperse.

According to a seventeenth embodiment, the porous microspheres according to any of the preceding embodiments are disclosed, wherein the bulk sample of the porous microspheres exhibits an angle-independent color as seen by the human eye. According to an eighteenth embodiment, the porous microspheres according to any one of Embodiments 1-16 are disclosed, wherein the bulk sample of the porous microspheres exhibits an angle-dependent color as seen by the human eye.

According to a nineteenth embodiment, a composition is disclosed comprising a support and porous microspheres according to any of the preceding embodiments. According to the twentieth embodiment, the composition according to embodiment 19 is disclosed, which is an aqueous composition, an oil-based composition, a coating composition, a food product, a paint, a plastic, a cosmetic composition, or a material for medical or safety use.

Examples

Example 1 Polymeric microspheres

The styrene/acrylic acid copolymer was prepared as follows: 230 ml of deionized water (DI) was added to a 3 neck reaction flask equipped with a thermometer, condenser, magnetic stirrer, under nitrogen atmosphere. The water was heated to 80° C. and 10 g of styrene was added with stirring, followed by 100 mg of acrylic acid dissolved in 10 ml of DI water via syringe. 100 mg of ammonium persulfate was dissolved in 10 ml of DI water and added to the stirred mixture via syringe. The reaction mixture was stirred for 24 hours at 80°C. The polymeric colloidal dispersion was allowed to cool to room temperature and purified by centrifugation to give polystyrene nanospheres having an average particle size of 250 nm.

Similarly, a styrene/acrylic acid copolymer is prepared to give polystyrene nanospheres having an average particle size of 350 nm.

The first aqueous colloidal dispersion of polystyrene (250 nm) was mixed with the second aqueous colloidal dispersion of polystyrene (350 nm) at wt./wt. the ratio of 7/3, and the mixture was diluted to 1 wt. % deionized water and sonicated to prevent particle agglomeration. Continuous oil phase contains 0.1 wt. % polyethylene glycol/perfluoropolyether surfactant in fluorinated oil. The aqueous colloidal dispersion and oil were each injected into a microfluidic device having a 50 µm diameter droplet formation unit through syringes connected to pumps. The system was allowed to equilibrate until monodisperse droplets formed. Monodisperse drops were collected in a reservoir.

The collected drops were dried in an oven at 45° C. for 4 hours to provide monodisperse polymeric microspheres. Monodisperse polystyrene microspheres contain polystyrene nanospheres having a bimodal particle size distribution.

Example 2 Porous Metal Oxide Microspheres

Example 1 was repeated by adding 1 wt. % silica nanoparticles to an aqueous mixture of the first and second colloidal dispersions before mixing with the oil phase to form a water-in-oil emulsion. The collected drops from the microfluidic device were dried as in Example 1 to form polymer matrix microspheres. The polymer matrix microspheres were calcined by placing on a silicon substrate, heating from room temperature to 500°C for 3 hours, maintaining at 500°C for 2 hours and cooling back to room temperature for 3 hours. Monodisperse silica monospheres are provided having an average diameter of 15 microns.

On FIG. 2 and FIG. 3 shows scanning electron microscope (SEM) images of a polymer matrix microsphere and a porous silica microsphere obtained in a similar manner.

Example 3 Porous Silica Microspheres Containing Light Absorber

The product from Example 2 is physically mixed with an aqueous dispersion of carbon black or powdered carbon black at various weights. Provided monodisperse porous microspheres of silicon oxide containing carbon black in the amount of 0.5 wt. %, 1 wt. %, 2 wt. %, 3 wt. %, 4 wt. % and 5 wt. %, based on the total weight of the microspheres.

Example 4 Drying Methods

Examples 1-3 were repeated, with microwave irradiation, vacuum drying and/or drying in the presence of a desiccant being used in the drying step.

Example 5 Preparation of Porous Silica Microspheres by Spray Drying

The styrene/acrylic acid copolymer was prepared as follows: 230 ml of deionized (DI) water was added to a three-necked reaction flask equipped with a thermometer, condenser, magnetic stirrer and nitrogen atmosphere. The water was heated to 80°C and 10 g of styrene was added with stirring, and then 100 mg of acrylic acid dissolved in 10 ml of deionized water was added via syringe. 100 mg of ammonium persulfate was dissolved in 10 ml of deionized water and added to the stirred mixture using a syringe. The reaction mixture was stirred for 24 hours at 80°C. The polymeric colloidal dispersion was allowed to cool to room temperature and purified by centrifugation to give polystyrene nanospheres with an average particle size of 250 nm.

Similarly, a styrene/acrylic acid copolymer is prepared to give polystyrene nanospheres having an average particle size of 350 nm.

The first aqueous colloidal dispersion of polystyrene (250 nm) was mixed with the second aqueous colloidal dispersion of polystyrene (350 nm) at wt./wt. the ratio of 7/3, and the mixture was diluted to 1 wt. % deionized water and 1 wt. % silica nanoparticles were added to the mixture, which was sonicated to prevent particle agglomeration. The aqueous dispersion was spray dried to provide polymer matrix microspheres containing polydisperse polymer nanospheres and silica. The microspheres were calcined by heating from room temperature to 500°C for 3 hours, stored at 500°C for 2 hours, and cooled back to room temperature for 3 hours. Received porous microspheres of silicon oxide.

Example 6 Visible color of bulk sample

In these examples of bulk color samples, 0.5 milligrams of porous microspheres were uniformly placed in a 10 ml clear glass jar having a bottom area of 6 cm. Color was observed by the human eye.

A sample of porous silica microspheres is prepared analogously to Example 2, with polystyrene nanospheres having average particle sizes of 420 nm and 460 nm w/w. 7:3 ratio. The sample shows a red color.

A sample of porous silica microspheres is prepared in accordance with the method of example 5, where polystyrene nanospheres have an average particle size of 360 nm and 420 nm wt./wt. ratio 4: 1 and wt./wt. the ratio of polymer and silicon oxide 4: 1. Porous microspheres have a porosity of 0.55 and have a pronounced green color. Samples are also prepared, where wt./wt. the ratio of polymer to silica is 2:1, providing porous microspheres having a porosity of 0.45 and exhibiting a pronounced orange color.

Example 7 Porous Zinc Oxide Microspheres

A sample of porous zinc oxide microspheres was obtained according to the method of Example 5, where the polystyrene nanospheres have an average particle size of 250 nm and 320 nm wt./wt. ratio of 1:1, and where wt./wt. the ratio of polymer and zinc oxide is 1:2.

Example 8 Porous Silica/Titanium Oxide Microspheres

A sample of porous microspheres containing silicon oxide and titanium oxide was obtained according to the method of Example 2, where polystyrene nanospheres have an average particle size of 350 nm and 460 nm wt./wt. ratio of 1:4, and where wt./wt. the ratio of polymer to metal oxide is generally 3:1. Wt/wt the ratio of silicon oxide and titanium oxide is 9:1.

Claims (23)

1. Porous microspheres containing metal oxide, where the microspheres have an average diameter of about 0.5 µm to about 100 µm, and an average porosity of about 0.10 to about 0.80; where the porous microspheres have more than one population of pores, each having an average pore diameter, where each population has a different average pore diameter, and where the average pore diameters are from about 50 nm to about 999 nm. 2. The porous microspheres of claim 1, wherein the microspheres have an average diameter of from about 1 micron to about 75 microns. 3. Porous microspheres according to claim 1, wherein the average pore diameters are from about 50 nm to about 800 nm. 4. The porous microspheres of claim 1, wherein the microspheres have an average porosity of about 0.45 to about 0.65. 5. Porous microspheres according to claim 1, where the microspheres have average diameter from about 4.5 µm to about 9.9 µm; an average porosity of about 0.45 to about 0.65; And average pore diameters from about 220 nm to about 300 nm. 6. Porous microspheres according to any one of paragraphs. 1-5 containing from about 60.0 wt.% to about 99.9 wt.% metal oxide based on the total weight of the microspheres. 7. Porous microspheres according to any one of paragraphs. 1-5, where the metal oxide is selected from the group consisting of silicon oxide, titanium oxide, alumina, zirconium oxide, cerium oxide, iron oxides, zinc oxide, indium oxide, tin oxide, chromium oxide, and combinations thereof. 8. Porous microspheres according to any one of paragraphs. 1-5 containing from about 0.1 wt.% to about 40.0 wt.% of one or more light absorbers based on the total weight of the microspheres. 9. Porous microspheres according to any one of paragraphs. 1-5, where a bulk sample of porous microspheres exhibits color as seen by the human eye. 10. Porous microspheres according to any one of paragraphs. 1-5, where the porous microspheres are monodispersed. 11. Composition suitable as a structural dye containing a substrate and porous microspheres according to any one of paragraphs. 1-5. 12. The composition of claim 11, wherein the composition is an aqueous formulation, an oil based formulation, a paint, a coating formulation, a food product, a plastic, a cosmetic formulation, or a material for medical or safety use. 13. Porous microspheres containing metal oxide, where a bulk sample of porous microspheres exhibits a color observed by the human eye; where the porous microspheres have more than one population of pores, each having an average pore diameter, where each population has a different average pore diameter selected from about 50 nm to about 999 nm, and where the porous microspheres have an average diameter of about 0.5 μm up to about 100 µm. 14. The porous microspheres of claim 13, wherein the bulk sample of the porous microspheres exhibits an angle-independent color as seen by the human eye. 15. The porous microspheres of claim 13, wherein the bulk sample of the porous microspheres exhibits an angle dependent color as seen by the human eye. 16. Composition suitable as a structural dye containing a substrate and porous microspheres according to any one of paragraphs. 13-15. 17. The composition of claim 16, wherein the composition is an aqueous formulation, an oil based formulation, a coating formulation, a food product, a paint, a plastic, a cosmetic formulation, or a material for medical or safety use.

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