CN116459168A - A kind of silica-encapsulated object-loaded mesoporous silicon and its preparation method and application - Google Patents

Abstract

The invention discloses a silicon dioxide encapsulated carrier mesoporous silicon, a preparation method and application thereof, and belongs to the technical field of chemical materials. According to the invention, organic or inorganic matters are loaded in the pores of mesoporous silicon, and the solid silicon dioxide layer is encapsulated on the outer surface, so that the prepared silicon ball can play a role in enhancing the functionality of the loaded matters, and simultaneously provide a good barrier effect, prevent the loaded matters and harmful matters generated by the loaded matters from being released, reduce harm and improve use safety.

Description

A kind of silica-encapsulated object-loaded mesoporous silicon and its preparation method and application

technical field

The invention belongs to the technical field of chemical materials, and more specifically relates to a silica-encapsulated object-carrying mesoporous silicon and a preparation method and application thereof.

Background technique

Some light, heat, and substances that are responsive or sensitive to external environmental stimuli are susceptible to environmental factors during the application process, and their stability decreases, or they produce harmful substances that cause harm to the environment and human body, limiting their application. Such as UV shielding or absorbing agents, commonly used in the preparation of sunscreen products for human skin UV protection. However, organic UV absorbers such as diethylaminohydroxybenzoyl hexyl benzoate (DHHB), 3-isooctyl diphenylacrylate (OCT), 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione (AVO), ethylhexyl triazone (UVT-150), bis-ethylhexyloxyphenol methoxyphenyl triazine ( S) etc. have health risks such as penetrating into the skin, causing endocrine disorders, and causing impaired reproductive ability. Inorganic UV absorbers such as nano titanium dioxide (TiO ₂ ), cerium oxide (CeO ₂ ), zinc oxide (ZnO), etc. will generate reactive oxygen species (ROS) under the irradiation of ultraviolet light. The reactive oxygen species will damage the cell structure, or degrade organic matter into small molecules and damage cells or the human body.

In order to provide full-band UV radiation protection, sunscreen products usually combine several organic UV absorbers with inorganic UV absorbers to combine different shielding ranges. However, the interaction between different UV absorbers limits their combined use. For example, the photocatalysis of inorganic UV absorbers may lead to the decomposition of organic UV absorbers and other organic substances in the system, resulting in the loss of UV protection effect and the generation of small molecular organic substances that are easy to permeate through the skin. In order to improve the compatibility, safety and sunscreen effect of UV absorbers, various methods have been adopted, including grafting organic absorbers onto inorganic absorbers, loading absorbers into nanoparticles, and coating polymer or inorganic substances on the surface of absorber particles, etc. However, these methods still have many problems, such as organic substances will be catalyzed and decomposed when in contact with inorganic absorbers, and nanoparticles formed by polymer-loaded UV absorbers only delay the release of organic absorbers, but cannot prevent the toxic side effects caused by skin penetration. Mesoporous silica (referred to as mesoporous silicon) has been widely used to support ultraviolet absorbers due to its good biocompatibility, thermal and chemical stability, and controllable particle size and porous structure. However, the loading of mesoporous silicon still has safety problems such as leakage of organic absorbers and the inability to shield the decomposition of organic components by the photocatalytic action of metal oxides. In addition, some organic flame retardants and dyes that need to be water-proof and leak-proof also need appropriate technology to solve the problems existing in the application.

Aiming at the above-mentioned problems in the application of sunscreens, flame retardants, etc., the present invention provides a silica-encapsulated load-carrying mesoporous silicon and its preparation method. By loading these organic or inorganic substances in the pores of the mesoporous silicon and encapsulating the outer surface with a solid silica layer, new and safe technologies and products are provided.

Contents of the invention

In view of this, the present invention provides a silica-encapsulated carrier-loaded mesoporous silicon, its preparation method and application.

In order to achieve the above object, the present invention adopts the following technical solutions:

A silicon dioxide-encapsulated object-loaded mesoporous silicon, comprising mesoporous silicon, a load and a silicon dioxide layer, wherein the load is loaded in the pores of the mesoporous silicon, and the outer surface is encapsulated with a solid silicon dioxide layer with a thickness ≥ 10 nm, and the particle size of the above-mentioned mesoporous silicon is greater than 150 nm.

Further, the above-mentioned mesoporous silicon has an active group amino, silanol or dopamine.

The beneficial effect of adopting the above further technical solution: the surface of mesoporous silicon is activated, which is beneficial to the stable loading of substances.

Further, the above-mentioned silicon dioxide layer is modified with surface functions.

The beneficial effect of adopting the above further technical solution is to improve the functionalities of the silica-encapsulated loaded mesoporous silicon, such as dispersibility, compatibility with other components, and the like.

Further, the above-mentioned loads are inorganic nanoparticles or organic or inorganic solids that are dried and precipitated from a solution.

Furthermore, the above-mentioned inorganic nanoparticles or inorganic solids are one or more of metals, metal oxides or non-metallic inorganic substances.

Further, the above-mentioned metal is silver and/or gold; the above-mentioned metal oxide is one or more of titanium dioxide, zinc oxide or cerium oxide; the above-mentioned non-metallic inorganic substance is carbon dots and/or inorganic perovskite nanocrystals.

Furthermore, the metal oxide mentioned above is an inorganic sunscreen agent.

The beneficial effect of adopting the above-mentioned further technical scheme: metal oxide nanoparticles have good ultraviolet light shielding effect, and are typical inorganic ultraviolet sunscreens, but their strong photocatalysis and the strong oxidation of active oxygen generated by photocatalysis will oxidize and degrade the organic matter in the surrounding environment, especially penetrate into the human body through the skin, causing damage such as cell damage. After the mesoporous silicon is loaded, it is encapsulated with a solid silicon layer, which can block the release of free radicals, prevent harm to the human body and the environment, and improve the safety of use.

Furthermore, the above-mentioned organic substances are water-insoluble organic substances.

The beneficial effect of adopting the above further technical solution: because the water-insoluble organic matter is more conducive to the encapsulation of the silicon layer, it will not be lost from the mesoporous silicon due to water solubility during the encapsulation process of the silicon layer.

Furthermore, the above-mentioned water-insoluble organic matter is an organic sunscreen.

Further, the above-mentioned organic sunscreens are diethylaminohydroxybenzoyl hexyl benzoate (DHHB), 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione (AVO), ethylhexyl triazone (UVT-150) 3-isooctyl diphenylacrylate (OCT) or bis-ethylhexyloxyphenol methoxyphenyl triazine ( S) one or a mixture of several.

The beneficial effect of adopting the above further technical solution: the above organic sunscreen agent is easy to penetrate into the body through the skin and be lost into the environment, causing harm. By adopting the technology of the invention, the mesoporous silicon loading and the encapsulation of the silicon layer can effectively prevent the release and skin penetration of organic sunscreens, and at the same time improve the photostability of these sunscreens, improve the anti-ultraviolet effect and aging effect.

Further, the particle size of the above-mentioned mesoporous silicon is 150 nm-5 μm.

The beneficial effect of adopting the above-mentioned further technical solution is that it is beneficial to the shielding effect of ultraviolet light and avoids the skin penetration of mesoporous silicon, and is also beneficial to the preparation and application of sunscreen products such as sunscreen, sunscreen lotion and spray. If the particle size is too large, the dispersibility and fluidity will be poor, which will affect the preparation and application of sunscreen products. If the particle size is too small, the particles will penetrate into the skin and cause damage.

Furthermore, the loading amount of the above-mentioned inorganic sunscreen agent or organic sunscreen agent accounts for 10-50% of the mass of the loaded mesoporous silicon.

Furthermore, the above-mentioned organic sunscreen or inorganic sunscreen is loaded in the pores of mesoporous silicon, and the outer surface is sealed with a solid silicon dioxide layer with a thickness greater than 20 nm.

The beneficial effect of adopting the above-mentioned further technical solution is to ensure the mechanical stability of the silicon layer, and to prevent the release of the encapsulated substance and its reaction product for a long time.

The present invention also provides a method for preparing the aforementioned silica-encapsulated loaded mesoporous silicon, comprising the following steps:

(1) Preparation of loaded mesoporous silicon by in-situ loading method, comprising the following steps:

Dispersing the mesoporous silicon and the precursor in a solvent, or dispersing the mesoporous silicon in a solvent, adding the precursor, or dispersing the precursor in a solvent, adding the mesoporous silicon; stirring, centrifuging, washing, drying, and high-temperature calcination to obtain the loaded mesoporous silicon loaded with inorganic nanoparticles;

Or, disperse the mesoporous silicon and the precursor in the solvent, stir, then evaporate the solvent at high temperature until the evaporation is complete, and finally calcine at high temperature to obtain the loaded mesoporous silicon loaded with inorganic nanoparticles;

Or, disperse the mesoporous silicon in the solvent, add the precursor, stir, add hydrogen peroxide to the reaction solution, adjust the pH, continue to stir, centrifuge, wash, dry, and calcinate at high temperature to obtain the loaded mesoporous silicon loaded with inorganic nanoparticles;

Or, disperse the precursor in a solvent, add mesoporous silicon, heat at high temperature, then naturally cool to room temperature, centrifuge, wash, and dry to obtain loaded mesoporous silicon loaded with inorganic substances;

Or, the preparation of loaded mesoporous silicon by physical loading includes the following steps:

In a closed reaction vessel, disperse the organic matter in the solvent, add mesoporous silicon, stir in a dark environment, then open the reaction vessel and continue stirring until the solvent is completely evaporated, and the organic matter-loaded mesoporous silicon is obtained;

Or, disperse the organic matter in a solvent, add mesoporous silicon, stir, centrifuge, wash, and dry to obtain the loaded mesoporous silicon loaded with organic matter;

Or, disperse the inorganic matter in the solvent, add mesoporous silicon, stir, centrifuge, and dry to obtain the loaded mesoporous silicon loaded with inorganic matter;

(2) A method for encapsulating silicon dioxide, comprising the following steps: adding a precursor component of silicon dioxide to an aqueous dispersion of loaded mesoporous silicon, stirring, centrifuging to obtain a solid product, washing, and drying to obtain loaded mesoporous silicon encapsulated by silicon dioxide.

Further, in step (1), the loaded mesoporous silicon is prepared by an in-situ loading method, and the above-mentioned precursor is a metal inorganic salt, a metal alkoxide or a mixture of hydrated citric acid and urea.

Furthermore, the above metal alkoxide is one or a mixture of isopropyl titanate, methyl titanate, ethyl titanate, n-propyl titanate, isopropyl titanate or butyl titanate.

Furthermore, the above metal inorganic salt is one or a mixture of zinc nitrate, zinc chloride or cerium nitrate hexahydrate.

Further, in step (1), the loaded mesoporous silicon is prepared by an in-situ loading method, and the above-mentioned solvent is an alcohol solvent, water or an alcohol-water mixed solution.

Further, in step (1), the loaded mesoporous silicon is prepared by an in-situ loading method. The mass ratio of the mesoporous silicon to the metal inorganic salt or metal alkoxide is 1:0.5-2; the mesoporous silicon and the precursor are dispersed in a solvent, or the mesoporous silicon is dispersed in a solvent, and the precursor is added, or the precursor is dispersed in a solvent, and the mesoporous silicon is added. The total concentration of the mesoporous silicon and the metal inorganic salt or metal alkoxide is 1.0-5.0 wt%.

Further, in step (1), the loaded mesoporous silicon is prepared by an in-situ loading method, the stirring temperature is 20-70° C., and the total stirring time is 1-24 hours.

Further, in step (1), the loaded mesoporous silicon is prepared by an in-situ loading method, and the stirring is performed under a nitrogen atmosphere.

Further, in step (1), preparing the loaded mesoporous silicon by adopting an in-situ loading method also includes adjusting the pH to 10 during the stirring process.

Further, in step (1), the loaded mesoporous silicon is prepared by an in-situ loading method, the temperature of the above-mentioned high-temperature calcination is 450-550° C., and the high-temperature calcination time is 4-6 hours.

Further, in step (1), the loaded mesoporous silicon is prepared by an in-situ loading method, the temperature of the above-mentioned high-temperature heating is 180° C., and the heating time is 4 hours.

Further, in step (1), the loaded mesoporous silicon is prepared by physical loading, and the above solvent is one or more of water, dichloromethane, n-hexane, ethanol or isopropanol.

Further, in step (1), the loaded mesoporous silicon is prepared by physical loading, the above-mentioned organic matter or inorganic matter is dispersed in the solvent, and the concentration of the organic matter or inorganic matter is 2-50 wt%;

Mesoporous silicon is added, the mass ratio of mesoporous silicon to organic matter or inorganic matter is 1:1-20, and the concentration of mesoporous silicon is 2-5 wt%.

Further, in step (1), the loaded mesoporous silicon is prepared by a physical loading method, the stirring temperature is 20-50° C., and the stirring time is always 1-24 hours.

Furthermore, in step (1), the carrier-loaded mesoporous silicon is prepared by using the method of physical loading. The above-mentioned organic substance is an organic sunscreen agent. In a closed reaction vessel, the organic sunscreen agent is dispersed in a solvent. The concentration of the organic sunscreen agent is 2-6 wt%, and the mesoporous silicon is added. The mass ratio of the mesoporous silicon to the organic sunscreen agent is 1:1-3, and the concentration of the mesoporous silicon is 2-5 wt%. porous silicon.

Further, in step (2), the precursor components of the above-mentioned silicon dioxide include: a mixed solution of isopropanol solution including or not including PVP with a mass fraction of 1.2%, ammonia water and tetraethyl orthosilicate (TEOS) and isopropanol or ethanol.

Further, in step (2), the sealing method of mesoporous silicon when loading inorganic nanoparticles or drying the precipitated inorganic matter from the solution: disperse the loaded mesoporous silicon into water to form an aqueous dispersion, add or not add isopropanol solution of PVP and ammonia water, drop in the mixed solution of TEOS and isopropanol or ethanol, stir and react at 20-60°C for 2-24 hours, centrifuge, wash the precipitate with water and ethanol three times, and dry to obtain the loaded mesoporous silicon encapsulated by silica;

Further, the volume ratio of the above-mentioned mesoporous silicon aqueous dispersion, PVP isopropanol solution, ammonia water, TEOS and isopropanol mixed solution or TEOS and ethanol mixed solution is 30:0-30:2-7:30-50, the volume content of TEOS in the TEOS-isopropanol mixed solution or TEOS-ethanol mixed solution is 9%-20%; Score 1.2%.

Further, in step (2), the sealing method of mesoporous silicon when loading the organic matter precipitated from the solution is: disperse the loaded mesoporous silicon in water, stir for 10 minutes, add ammonia water, slowly drop in TEOS, stir at room temperature for 3 hours, centrifuge, wash with water and ethanol three times, and dry to obtain the organic-loaded mesoporous silicon of the silica sealing layer.

Further, the mass volume ratio of the loaded mesoporous silicon to water is 0.2g:100-120mL, and the volume ratio of water, ammonia water and TEOS is 100-120:0.6-1.0:0.6-1.5.

The thickness of the aforementioned silicon layer is controlled by the concentration of the precursor, the stirring time and the stirring speed.

Further, in the above preparation method, the surface activation of mesoporous silicon is also included, so that it has amino, silanol or dopamine active groups.

An application of silica-encapsulated loaded mesoporous silicon in the preparation of coatings, skin care products, flame-retardant or sunscreen fabrics, the above-mentioned silica-encapsulated loaded mesoporous silicon is used to prepare emulsions, dispersions, solid or semi-solid products.

Further, when the above-mentioned load is an inorganic sunscreen or an organic sunscreen, the loaded mesoporous silicon encapsulated by silica is used to prepare an anti-ultraviolet radiation product, and the above-mentioned anti-ultraviolet radiation product includes a sunscreen product for skin or an ultraviolet protective coating.

Furthermore, the above-mentioned anti-ultraviolet radiation product is a product with anti-ultraviolet function prepared from one or more mixtures of carrier-loaded mesoporous silicon encapsulated in silicon dioxide and plastics, fibers or inorganic materials.

Beneficial effects of the present invention: the present invention loads organic or inorganic substances in the pores of mesoporous silicon, and encapsulates a solid silicon dioxide layer on the outer surface. The silicon spheres prepared by the present invention provide a good barrier effect while exerting and promoting the functionality of the load, prevent the release of the load and the harmful substances produced by it, reduce hazards, and improve the safety of use. The particle size of mesoporous silicon is greater than 150nm to avoid its skin penetration and improve application safety. also. Mesoporous silicon with large particle size can have larger pores, which is beneficial to increase the loading capacity of organic and inorganic substances. Taking the loading of sunscreens as an example, the innovation and features are: (1) to play and effectively protect the anti-ultraviolet function of organic and inorganic sunscreens. At the same time, the silica layer can effectively block the release of active oxygen and organic sunscreens produced by the photocatalysis of sunscreens, thereby preventing the contact of active oxygen and organic sunscreens with the skin, and preventing safety problems caused by entering the body through the skin; (2) As a platform technology, the technology of the present invention is applicable to organic and inorganic sunscreens that are widely used at present, and the encapsulation layer technology also avoids the interaction between different sunscreens and the impact on them. Degradation of other organic components in sunscreen products; (3) The surface sealing layer of silicon dioxide normalizes the surface properties, which has nothing to do with the physical and chemical properties of the sunscreen, providing convenient conditions for the combination and application of various sunscreens, and also provides convenience for the preparation of sunscreens, coatings, etc.; (4) The silicon dioxide and mesoporous silicon used are substances that exist in nature, and the raw materials are easily available and environmentally friendly. Functional modification to improve functionality.

Description of drawings

Figure 1: Particle morphology of mesoporous silicon prepared in Examples 1 and 5, mesoporous silicon loaded with titanium dioxide, and mesoporous silicon loaded with titanium dioxide and sealed.

Fig. 2: Infrared spectra (FTIR) of the mesoporous silicon in Examples 1 and 5, the mesoporous silicon loaded with titania, and the mesoporous silicon particles loaded with titania and sealed.

Fig. 3: The energy spectrum of the titanium dioxide-loaded and sealed mesoporous silicon particles prepared in Example 5.

Figure 4: Example 1, 5 photocatalytic shielding effect of particles loaded with titanium dioxide on mesoporous silicon and sealed.

Figure 5: The mechanical stability of the particles after mesoporous silicon-loaded inorganic sunscreens and seals in Examples 1, 5 and 9 are reflected by the photocatalytic shielding effect. Among them, (1) is SiO ₂ @MSN-4/ZnO, (2) is mechanically stirred SiO ₂ @MSN-4/ZnO, (3) is a mixture of MSN, ZnO, SiO ₂ , (4) is SiO ₂ @MSN-1/TiO ₂ , (5) is mechanically stirred SiO ₂ @MSN-1/TiO ₂ , (6) is MSN, TiO ₂ , SiO ₂ mixture.

Fig. 6: The ultraviolet shielding effect of mesoporous silicon, mesoporous silicon loaded with titanium dioxide, and mesoporous silicon loaded with titanium dioxide and sealed in Example 1 and 5.

Fig. 7: Particle morphology of mesoporous silicon in Examples 1 and 9, mesoporous silicon loaded with zinc oxide, and mesoporous silicon loaded with zinc oxide and sealed.

Figure 8: Particle morphology of mesoporous silicon in Examples 1 and 11, mesoporous silicon loaded with DHHB, and mesoporous silicon loaded with DHHB and sealed.

Figure 9: Infrared spectra (FTIR) of mesoporous silicon in Examples 1 and 11, mesoporous silicon loaded with DHHB, and mesoporous silicon particles loaded with DHHB and sealed.

Fig. 10: The energy spectrum of the mesoporous silicon loaded with DHHB and sealed in Example 11.

11 : DHHB release rate test of DHHB-loaded mesoporous silicon and DHHB-loaded and sealed mesoporous silicon in Example 11.

Fig. 12: Percutaneous penetration test of DHHB-loaded mesoporous silicon and DHHB-loaded and sealed mesoporous silicon in Example 11.

Fig. 13: UV shielding effect of mesoporous silicon in Examples 1 and 11, mesoporous silicon loaded with DHHB, and mesoporous silicon loaded with DHHB and sealed layer.

Figure 14: Particle morphology of mesoporous silicon in Examples 1 and 13, mesoporous silicon loaded with AVO, and mesoporous silicon loaded with AVO and sealed.

Figure 15: Photostability test of the ultraviolet shielding effect of mesoporous silicon loaded with AVO and AVO loaded and sealed in Example 13.

Figure 16: UV shielding effect test of sunscreen UV intensity sensor card.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

Example 1

Preparation of mesoporous silicon MSN-1:

Add 240mL of water, 160mL of absolute ethanol and 5g of cetyl ammonium chloride (CTAC) aqueous solution with a mass fraction of 25% into the three-necked flask, use a magnetic stirrer, stir at 800rpm for 5min, then add 4.8g of PEG-400, and continue stirring for 20min. After that, 12 mL of dodecane was added and vigorously stirred at 1200 rpm for 20 min. Then, 15 g of Pluronic 123 (P123) and 3.2 mL of ammonia water were added. Finally, 10 mL of tetraethyl orthosilicate (TEOS) was slowly dropped into the mixture, and the reaction was stirred at 60° C. at 600 rpm for 3 h. The solution obtained by the reaction was centrifuged to remove the supernatant, washed three times with water and ethanol respectively, and evaporated to dryness at 70°C. The obtained powder was calcined at 550° C. for 5 h to finally obtain mesoporous silicon MSN-1. The size and shape are shown in Figure 1A and Table 1. Figure 1 ASEM and TEM images show that the prepared mesoporous silicon MSN-1 is spherical (average particle size 300 ± 10nm) and porous structure.

Embodiment 1～20 among the present invention, what all adopt is magnetic stirrer (Beijing Xingde Instrument Equipment Co., Ltd., model 85-1, stirring speed 0-2600rpm, power 20W)

Example 2

Preparation of Mesoporous Silicon MSN-2

According to the method of Example 1, 120mL of water, 80mL of absolute ethanol, 10g of P123 and 10mLTEOS were added to a three-necked flask to prepare mesoporous silicon MSN-2 with a particle size of 500±23nm.

Example 3

Preparation of Mesoporous Silicon MSN-3

According to the literature (Yu-ChihLin, et al. Colloids and Surfaces B: Biointerfaces 202 (2021) 111658) method, 8gP123 was dissolved in 240mL HCl (2M) at 30°C and stirred at 500rpm for 1h, then 9.1mLTEOS was added and reacted at room temperature for 24h, and at 90°C for 12h. The resulting solid was filtered, washed with water, and dried at 100° C. for 5 h. The solid was calcined at 550° C. for 5 h to obtain mesoporous silicon MSN-3 with a particle size of 1±0.05 μm.

Example 4

Preparation of Mesoporous Silicon MSN-4

According to the method of Example 3, 4gP123 was dissolved in 160mL HCl (2M) at 30°C and stirred at 500rpm for 1h, then 9.1mLTEOS was added and reacted at room temperature for 24h, and at 90°C for 24h. The resulting solid was filtered, washed with water, and dried at 100° C. for 5 h. The solid was calcined at 550° C. for 5 h to obtain mesoporous silicon MSN-4 (5.0±0.5 μm).

Example 5

Preparation of TiO2-supported Mesoporous Silicon Encapsulated by Silicon Layer

(1) Preparation of titanium dioxide-supported mesoporous silicon (MSN-1/TiO ₂ -a)

Disperse 0.3g of MSN-1 and 0.32mL (0.3072g) of isopropyl titanate in 25mL of ethanol, pass through nitrogen to remove oxygen, and stir at 600rpm under nitrogen atmosphere for 24 hours at room temperature (20-25°C). The solution was centrifuged to obtain a solid product, which was washed three times with water and ethanol, respectively, and dried. The product was placed in a muffle furnace, and the temperature was raised to 550° C. at a rate of 2° C./min and maintained for 5 hours to obtain titanium dioxide-loaded mesoporous silicon MSN-1/TiO ₂ .

(2) Encapsulation of titanium dioxide-loaded mesoporous silicon (SiO ₂ @MSN-1/TiO ₂ )

Disperse 0.2 g of titanium dioxide-supported mesoporous silicon in 30 mL of water and stir at 800 rpm for 5 min to form an aqueous dispersion. Then 30 mL of isopropanol solution of PVP with a mass fraction of 1.2% was added. Add 5mL of ammonia to provide an alkaline environment. Finally, a mixture of 3 mLTEOS and 30 mL isopropanol was added dropwise, and the reaction was stirred at room temperature at 600 rpm for 24 hours. Centrifuge, wash the precipitate three times with water and ethanol, and dry to obtain silica-encapsulated mesoporous silicon-based titanium dioxide (SiO ₂ @MSN-1/TiO ₂ ), the structure and properties of which are shown in Figures 1-6, 16 and Table 1.

Figure 1B shows that there are nano-sized TiO ₂ particles inside and outside the mesoporous silicon, and the surface of SiO ₂ @MSN-1/TiO ₂ becomes smooth after the silicon layer is encapsulated (Figure 1C), and the existence of mesopores cannot be observed by TEM. The average thickness of the silicon layer on the surface of SiO ₂ @MSN-1/TiO ₂ is 15nm measured by the change of particle size.

The comparison of the infrared spectra in Figure 2 shows the loading of _TiO2 and the encapsulation of the surface silicon layer; the surface element analysis in Figure 3 also proves the distribution of O, Si, and Ti elements on the silicon spheres; the photocatalytic shielding effect experiment results in Figure 4 show that in the presence of MSN-1/ _TiO2 , after ultraviolet light, the active oxygen generated by the photocatalysis of _TiO2 leads to the decomposition of methyl orange, so that the concentration of methyl orange in the solution decreases sharply with the time of ultraviolet light. However, SiO ₂ @MSN-1/TiO ₂ with SiO ₂ capping layer can effectively reduce the decomposition of methyl orange, therefore, the concentration of methyl orange solution drops less.

Figure 5 shows the photocatalytic shielding effect of mesoporous silicon-loaded inorganic sunscreens and sealed particles after mechanical stirring treatment. Compared with SiO ₂ @MSN-1/TiO ₂ (4) before mechanical stirring treatment, the photocatalytic shielding effect of SiO ₂ @MSN-1/TiO ₂ (5) after mechanical stirring treatment was almost unchanged, while the photocatalytic effect of MSN, TiO ₂ and SiO ₂ mixture (6) was very obvious, resulting in a sharp drop in the concentration of methyl orange. The silicon layer has better stability, and the silicon layer is not damaged under mechanical stirring. In Table 1, the C _96/ C ₀ of SiO ₂ @MSN-1/TiO ₂ is 90.1%, indicating that after grinding, pressure and mechanical stirring, the particles can ensure that 90% of the methyl orange is not decomposed after 96 hours of ultraviolet light (Table 1), further illustrating the stability of the silicon layer.

Fig. 6 compares the ultraviolet shielding effect of the mesoporous silicon in Examples 1 and 5, the mesoporous silicon loaded with titanium dioxide, and the mesoporous silicon loaded with titanium dioxide and sealed. The ultraviolet shielding effect of mesoporous silicon is poor, and the concentration of methyl orange decreases rapidly under ultraviolet light; while the ultraviolet shielding effect of SiO ₂ @MSN-1/TiO ₂ is better, slightly lower than that of MSN-1/TiO ₂ under the same quality, because the coating of the silicon layer reduces the content of TiO ₂ relatively.

Example 6

Preparation of TiO2-supported Mesoporous Silicon Encapsulated by Silicon Layer

Disperse 0.3g of MSN-4 in 35mL of ethanol, pass through nitrogen to remove oxygen, add 0.6mL (0.576g) of isopropyl titanate, and stir at room temperature at 600rpm for 24 hours under nitrogen atmosphere. The solution was centrifuged to obtain a solid product, which was washed three times with water and ethanol, respectively, and dried. Put the product in a muffle furnace, raise the temperature to 550°C at a rate of 2°C/min and maintain it for 5h to obtain titanium dioxide-loaded mesoporous silicon MSN-4/TiO ₂ ;

Disperse 0.2 g of MSN-4/ _TiO2 in 30 mL of water and stir at 800 rpm for 5 min. Then 30 mL of isopropanol solution of PVP with a mass fraction of 1.2% was added. Add 7mL of ammonia to provide an alkaline environment. Finally, a mixture of 10 mL LTEOS and 40 mL isopropanol was added dropwise, and the reaction was stirred at room temperature at 600 rpm for 30 hours. After centrifugation, the precipitate was washed three times with water and ethanol, and dried to obtain silica-encapsulated mesoporous silicon-based titanium dioxide (SiO ₂ @MSN-4/TiO ₂ ), the structure and properties of which are shown in Table 1.

The data in Table 1 shows that MSN-4/TiO ₂ has a titanium dioxide loading of 50%, and the silicon layer thickness of SiO ₂ @MSN-4/TiO ₂ is 50nm, so it exhibits high stability and anti-ultraviolet effect.

Example 7

Preparation of TiO2-supported Mesoporous Silicon Encapsulated by Silicon Layer

(1) Preparation of titanium dioxide-supported mesoporous silicon (MSN-2/TiO ₂ )

Disperse 0.3g of MSN-2 and 0.22mL (0.211g) of isopropyl titanate into 40mL of butanol, stir at 600rpm at 45°C for 1h, then evaporate butanol at 160°C for 2 hours, and finally calcined at 450°C for 6h to obtain titanium dioxide-supported mesoporous silicon MSN-2/TiO ₂ .

(2) Encapsulation of titanium dioxide-loaded mesoporous silicon (SiO ₂ @MSN-2/TiO ₂ )

Disperse 0.2 g of titanium dioxide-loaded mesoporous silicon in 30 mL of water and stir at 700 rpm for 5 min. Then 30 mL of isopropanol solution of PVP with a mass fraction of 1.2% was added. Add 5mL of ammonia to provide an alkaline environment. Finally, a mixture of 5 mLTEOS and 30 mL isopropanol was added dropwise, and the reaction was stirred at room temperature at 700 rpm for 24 hours. After centrifugation, the precipitate was washed three times with water and ethanol, and dried to obtain silica-encapsulated mesoporous silicon-based titanium dioxide (SiO ₂ @MSN-2/TiO ₂ ), the properties of which are shown in Table 1.

Example 8

Preparation of TiO2-supported Mesoporous Silicon Encapsulated by Silicon Layer

(1) Preparation of TiO2-supported mesoporous silicon (MSN-3/TiO ₂ )

Disperse 0.3g of MSN-3 into 25mL of ethanol and 5mL of water, add 0.316g of tetrabutyl titanate, and stir at 600rpm at 70°C for 8h. The solid product was collected by centrifugation, washed, dried, and finally calcined at 500° C. for 4 hours to obtain titanium dioxide-loaded mesoporous silicon MSN-3/TiO ₂ .

(2) Encapsulation of titanium dioxide-loaded mesoporous silicon (SiO ₂ @MSN-3/TiO ₂ )

Disperse 0.2 g of titanium dioxide-loaded mesoporous silicon in 30 mL of water and ultrasonically disperse for 30 min. Then 3mL of ammonia water was added to provide an alkaline environment. After the system was heated to 45°C, a mixture of 8mLTEOS and 35mL of ethanol was added dropwise, and the reaction was stirred at 45°C at 600rpm for 14 hours. After centrifugation, the precipitate was washed three times with water and ethanol, and dried to obtain silica-encapsulated mesoporous silicon-based titanium dioxide (SiO ₂ @MSN-3/TiO ₂ ), the properties of which are shown in Table 1.

Example 9

Preparation of Zinc Oxide-loaded Mesoporous Silicon Encapsulated by Silicon Layer

(1) Preparation of supported zinc oxide mesoporous silicon (MSN-1/ZnO)

Disperse 1g of MSN-1 in 50mL of water, add 0.5g of zinc chloride, and stir at room temperature (22-25°C) at 600rpm for 12h. Aqueous sodium hydroxide solution was added dropwise to the reaction liquid until pH = 10, and the reaction was continued for 12 h. The reaction product was centrifuged, washed, dried, and calcined at 550° C. for 4 h in a muffle furnace to obtain zinc oxide-loaded mesoporous silicon MSN-1/ZnO.

(2) Encapsulation of ZnO-loaded mesoporous silicon (SiO ₂ @MSN-1/ZnO)

Disperse 0.2 g of zinc oxide-loaded mesoporous silicon in 30 mL of water and stir at 600 rpm for 5 min. Then 30 mL of isopropanol solution of PVP with a mass fraction of 1.2% was added. Add 5mL of ammonia to provide an alkaline environment. Finally, a mixture of 4 mLTEOS and 30 mL isopropanol was added dropwise, and the reaction was stirred at room temperature at 600 rpm for 24 hours. Centrifuge, wash the precipitate three times with water and ethanol, and dry to obtain silica-encapsulated mesoporous silicon-based zinc oxide (SiO ₂ @MSN-4/ZnO). The structure and properties are shown in Figures 5, 7 and Table 1.

Figure 7B shows that there are nano-sized ZnO particles inside and outside the mesoporous silicon, and the surface of SiO ₂ @MSN-1/ZnO becomes smooth after the silicon layer is encapsulated (Figure 7C), and the existence of mesopores cannot be observed by TEM, indicating the coating of the solid silicon layer on the surface. The average thickness of the silicon layer on the surface of SiO ₂ @MSN-1/ZnO was measured to be 17nm by the change of particle size.

Fig. 5. The photocatalytic shielding effect of mesoporous silicon-loaded inorganic sunscreens and sealed particles after mechanical stirring treatment. Compared with SiO ₂ @MSN-1/ZnO (1) before mechanical stirring treatment, the photocatalytic shielding effect of SiO ₂ @MSN-1/TiO ₂ (2) after mechanical stirring treatment was almost unchanged, while the photocatalytic effect of MSN-1, ZnO, SiO ₂ mixture (3) was very obvious, resulting in a sharp drop in the concentration of methyl orange. The layer has good stability, and the silicon layer is not damaged under mechanical stirring. In Table 1, the C _96/ C ₀ of SiO ₂ @MSN-1/ZnO is 90.4%, indicating that after grinding, pressure and mechanical stirring, the particles can ensure that 90% of the methyl orange is not decomposed after 96 hours of ultraviolet light (Table 1), further illustrating the stability of the silicon layer.

Example 10

Preparation of supported ceria mesoporous silicon encapsulated by silicon layer

(1) Preparation of supported ceria mesoporous silicon (MSN-5/CeO ₂ )

Commercial mesoporous silicon (150 nm, Hangzhou Xinqiao Biotechnology Co., Ltd., denoted as MSN-5) was used.

At room temperature, 1 g of MSN-5 was dispersed in 40 mL of water, 0.96 g of cerium nitrate hexahydrate was added, and stirred at 600 rpm for 12 h. A certain amount of hydrogen peroxide was added to the reaction solution, and ammonia water was added dropwise to pH=10, and the reaction was continued for 12 hours. The reaction product was centrifuged, washed, dried, and calcined at 550° C. for 4 hours in a muffle furnace to obtain ceria-loaded mesoporous silicon MSN-5/CeO ₂ .

(2) Encapsulation of ceria-loaded mesoporous silicon (SiO ₂ @MSN-5/CeO ₂ )

Disperse 0.2 g of ceria-loaded mesoporous silica in 30 mL of water and stir for 5 min. Then 20 mL of isopropanol solution of PVP with a mass fraction of 1.2% was added. Add 5mL of ammonia to provide an alkaline environment. Finally, a mixture of 3 mL LTEOS and 27 mL isopropanol was added dropwise, and the reaction was stirred at room temperature for 24 h. Centrifuge, wash the precipitate with water and ethanol three times, and dry to obtain mesoporous silicon-based cerium oxide encapsulated in silica (SiO ₂ @MSN-5/CeO ₂ ).

Table 1 Structural properties of the silica-encapsulated loaded mesoporous silicon prepared in Examples 5-10

^a is relative to the percentage content of the loaded mesoporous silicon; ^b is the ratio of the concentration C ₉₆ of the methyl orange solution to the initial concentration C ₀ after _the particles are dispersed in the methyl orange aqueous solution as a photocatalyst and irradiated by ultraviolet rays for ₉₆ hours ^; Without any sunscreen treatment, the methyl orange aqueous solution was irradiated by ultraviolet light (302nm, 8w), and the C ₃₀ /C ₀ was 3.6%.

Example 11

Preparation of Diethylaminohydroxybenzoyl Hexyl Benzoate (DHHB) Mesoporous Silica Encapsulated by Silicon Layer

(1) Preparation of DHHB-loaded mesoporous silicon (MSN-1/DHHB)

Disperse 0.4 g of DHHB in 10 mL of dichloromethane, and add 0.2 g of mesoporous silicon. Stir for 6 hours at 30°C in a dark environment to make the mesoporous silicon fully adsorb DHHB. Open the reaction vessel and keep stirring, and slowly evaporate the dichloromethane to dryness to obtain DHHB-loaded mesoporous silicon (MSN-1/DHHB).

(2) Silicon layer encapsulation of DHHB mesoporous silicon (SiO ₂ @MSN-1/DHHB)

Disperse 0.2g MSN-1/DHHB in 120mL water, stir for 10min, and add 1.0mL ammonia water. Afterwards, 1.5mLTEOS was slowly added dropwise, and stirred at room temperature for 3h. Centrifuge, wash with water and ethanol three times, and dry to obtain DHHB-loaded mesoporous silicon sealed with silica. The stirring speed in this example is 400 rpm. The structure and properties are shown in Figures 8-13, 16 and Table 2.

Figure 8 shows the SEM and TEM photos of MSN-1/DHHB and SiO ₂ @MSN-1/DHHB. It can be seen that the surface of mesoporous silicon is rough and the mesopores almost disappear after loading DHHB. After encapsulating the silicon layer, the grain size becomes larger and the surface is smooth. The thickness of the silicon layer is about 40nm (Table 2), and it has a high anti-ultraviolet effect (Table 2).

Figure 9 shows that MSN-1/DHHB has obvious vibration peaks of DHHB characteristic groups in the range of 600-1200 cm ^-1 , and the characteristic vibration peaks of DHHB are weakened after encapsulating the silicon layer. The distribution of O, Si, and N elements in the energy spectrum of Fig. 10 illustrates the uniform distribution of DHHB in mesoporous silicon.

Figure 11 shows the in vitro release curves of MSN-1/DHHB and SiO ₂ @MSN-1/DHHB. DHHB is released from MSN-1/DHHB quickly, but due to the barrier of the outer solid SiO ₂ layer, DHHB can hardly be released from SiO ₂ @MSN-1/DHHB. Therefore, the encapsulation of the silicon layer can effectively prevent the loss of DHHB. The results of percutaneous penetration experiments in Figure 12 further prove that due to the barrier of the silicon layer, SiO ₂ @MSN-1/DHHB hardly penetrates into the skin with DHHB, indicating that it provides good safety. Moreover, the mechanical stability results in Table 2 demonstrate that there is almost no loss of DHHB loaded in the particles when subjected to grinding, pressure and stirring.

The UV resistance performance in Figure 13 shows that SiO ₂ @MSN-1/DHHB coated with silicon layer exhibits similar or slightly better UV resistance than MSN-1/DHHB. It shows that the coating of silicon layer does not affect the anti-ultraviolet function of the organic ultraviolet absorber.

Example 12

According to the method of Example 11, the difference is that 0.2 g of MSN-5 and 0.2 g of DHHB are used, and ethanol is used as a solvent to obtain MSN-1/DHHB-b; then 0.2 g of MSN-1/DHHB is dispersed in 100 mL of water, stirred at 500 rpm for 10 min, and 0.6 mL of ammonia water is added. Afterwards, 0.6mLTEOS was slowly added dropwise, and stirring was continued for 3h at room temperature. Centrifuge, wash with water and ethanol three times, and dry to obtain DHHB-loaded mesoporous silicon, SiO ₂ @MSN-1/DHHB-b, which is sealed with silica. As shown in Table 2, the silicon layer thickness of SiO ₂ @MSN-1/DHHB-b is 20nm, and the anti-ultraviolet effect is lower than that of SiO ₂ @MSN-1/DHHB.

Table 2 Structural properties of the silica-encapsulated loaded mesoporous silicon prepared in Examples 11-14

^a is relative to the percentage content of the loaded mesoporous silicon; ^b is ground for 5 minutes, pressed under a pressure of 20MPa for 5 minutes, and mechanically stirred at 250rpm in ethanol for 5 minutes. The retention rate (%) of the organic load in the particle represents the stability of the silicon layer encapsulation; ^c The particle is placed on the methyl orange aqueous solution as an ultraviolet absorber and the ratio of the concentration C of the methyl orange solution to the initial concentration C after ultraviolet radiation for _30h ;

Example 13

Mesoporous silicon and silicon layer loaded with 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione (AVO)

According to the method of Example 11, the difference is that 0.3g of MSN-5 and 0.6g of AVO are used, and isopropanol is used as a solvent to obtain MSN-1/AVO; then, 0.2g of MSN-1/AVO is dispersed in 110mL of water, stirred at 500rpm for 10min, and 0.8mL of ammonia water is added. Afterwards, 1.0 mLTEOS was slowly added dropwise, and stirred at 400 rpm for 3 h at room temperature. Centrifuge, wash with water and ethanol three times, and dry to obtain AVO-loaded mesoporous silicon sealed with silica, SiO ₂ @MSN-1/AVO.

Figure 14 shows the SEM and TEM photos of MSN-1/AVO and SiO ₂ @MSN-1/AVO. It can be seen that the surface of mesoporous silicon is rough and the mesopores almost disappear after loading AVO, and the particles become larger and the surface is smooth after encapsulating the silicon layer.

As shown in Table 2, the silicon layer thickness of SiO ₂ @MSN-1/AVO is 35nm, which has high mechanical stability; SiO ₂ @MSN-1/AVO has a good anti-ultraviolet effect, because the AVO loading of MSN-1/AVO is high, reaching 50%.

Figure 15 compares the stability of the UV shielding properties of AVO and SiO ₂ @MSN-1/AVO. AVO is easily decomposed by ultraviolet radiation, and its UV resistance performance will decrease. It can be seen in Figure 15 that after 24 hours of ultraviolet radiation at two wavelengths, the color of the color chart coated with AVO becomes darker, indicating that the shielding effect of ultraviolet light is weakened; while the color chart coated with SiO ₂ @MSN-1/AVO still maintains a lighter color after 24 hours of ultraviolet radiation, indicating that SiO ₂ @ MSN-1/AVO effectively promoted the stability of AVO's UV shielding effect.

Example 14

According to the method of Example 11, except that 0.25 g of MSN-3 and 0.5 g of ethylhexyl triazone (UVT-150) were used to prepare mesoporous silicon MSN-3/UVT-150 encapsulating UVT-150 and mesoporous silicon SiO ₂ @MSN-3/UVT-150 coated with silica. The performance is shown in Table 2.

Example 15

According to the method of Example 11, the difference is that 0.5gMSN-4, 0.6g of two-ethylhexyloxyphenol methoxyphenyl triazine ( S), tetrahydrofuran is a solvent, preparation entrapment/> S mesoporous silicon MSN-4/> Mesoporous silicon SiO ₂ @MSN-4/> with S and silicon dioxide capping layer S. The performance is shown in Table 2.

Example 16

How to prepare sunscreen:

Component A: polydimethylsiloxane (PDMS, Mn=800) 51.5g, sodium dodecylbenzenesulfonate 2g, stearic acid 1.85g;

Component B: 6.5g glycerin, 16.5g 1,4-butanediol, 145g water;

Component C: 30 g each of the mesoporous silicon particles SiO ₂ @MSN-1/TiO ₂ and SiO ₂ @MSN-1/DHHB obtained in Examples 5 and 11 above, carrying a sealing layer.

Stir component A at 60°C at 1000rpm, add component B, continue stirring at room temperature, finally add component C, and stir at room temperature at 400rpm for 24h.

As shown in Figure 16, the anti-ultraviolet effect is represented by the color change of the color chart under _ultraviolet irradiation. It can be seen that SiO ₂ @MSN-1/TiO ₂ has a good shielding effect on 304nm ultraviolet light. The protective effect of 304nm ultraviolet light is weak; the sunscreen prepared by SiO ₂ @MSN-1/TiO ₂ and SiO ₂ @MSN- ₁ /DHHB in Example 16 has a good protective effect on both wavelengths of ultraviolet light _, which is similar to the function of commercial SPF50+ anti-ultraviolet products.

Example 17

Amino-functionalized mesoporous silica-supported phytic acid:

(1) Add 2g of MSN-1 and 120mL of absolute ethanol to a round-bottomed flask. Under nitrogen protection, add 2mL of 3-aminopropyltrimethoxysilane dropwise, reflux at 80°C for 16h, then wash with suction and dry at 80°C to obtain amino-functionalized mesoporous silicon (NH ₂ -MSN-1).

(2) Dissolve 4 g of phytic acid (PA) powder in 10 mL of deionized water, stir evenly at room temperature, add 0.25 g of NH ₂ -MSN-1 after the powder is completely dissolved, stir at 800 rpm at 50°C for 12 h, then centrifuge and wash, and place the centrifuged product in a vacuum oven to dry in vacuo to obtain phytic acid-loaded mesoporous silicon MSN-1/PA.

(3) Disperse 0.2g of MSN-1/PA in 30mL of water and stir for 5min. Then 30 mL of isopropanol solution of PVP with a mass fraction of 1.2% was added. Add 5mL of ammonia to provide an alkaline environment. Finally, a mixture of 3 mL LTEOS and 30 mL isopropanol was added dropwise, and the reaction was stirred at room temperature for 24 h. After centrifugation, the precipitate was washed three times with water and ethanol, and dried to obtain phytic acid-loaded mesoporous silicon (SiO ₂ @MSN-1/PA) encapsulated in silica. The stirring speed in this example was 400 rpm.

In the prepared SiO ₂ @MSN-1/PA, the mass percentage of phytic acid in MSN-1/PA is 50%, and the thickness of the silicon dioxide layer is 35nm. At room temperature, MSN-1/PA and SiO ₂ @MSN-1/PA were soaked in distilled water respectively, centrifuged after 10 days, the concentration of PA in distilled water was measured, and the loss rate of PA was calculated, which were 85% and 1%, respectively. It shows that after the silicon layer is encapsulated, it can prevent the dissolution of water-soluble PA.

Example 18

Carboxylated Mesoporous Silica Supported Ammonium Phytate

Suspend 0.25 g of NH ₂ -MSN-1 prepared in Example 17 in 20 ml of dimethylformamide (DMF), add it into DMF with 0.5 g of succinic anhydride, stir at room temperature for 24 hours, centrifuge, wash with absolute ethanol and deionized water, and dry in an oven to obtain carboxylated mesoporous silicon COOH-MSN-1.

Dissolve 5 g of ammonium phytate (PAA) powder in 10 ml of deionized water, stir evenly at room temperature, add 0.5 g of COOH-MSN-1 after the powder is completely dissolved, continue to stir for 24 hours, then centrifuge and wash, and place the centrifuged product in a vacuum drying oven to dry in vacuo to prepare ammonium phytate-loaded mesoporous silicon spheres MSN-1/PAA. In this embodiment, the stirring speed is 800 rpm.

Encapsulation of silicon layer:

Disperse 0.2g of MSN-1/PAA in 30mL of water and stir for 30min, then add 15mL of isopropanol solution of PVP with a mass fraction of 1.2%, add 2mL of ammonia water, drop in a mixture of 5mLTEOS and 20mL of isopropanol, and react at 60°C for 2h. The solid obtained from the reaction was filtered, washed with water and ethanol three times, and dried to obtain mesoporous silicon loaded with ammonium phytate (SiO ₂ @MSN-1/PAA) encapsulated in silica. The stirring speed in this example was 400 rpm.

In the prepared SiO ₂ @MSN-1/PAA, the mass percentage of ammonium phytate in MSN-1/PA is 20%, and the thickness of the silicon dioxide layer is 20nm. At room temperature, MSN-1/PAA and SiO ₂ @MSN-1/PAA were soaked in distilled water respectively, centrifuged after 10 days, the concentration of PAA in distilled water was measured, and the loss rate of PAA was calculated, which were 90% and 0.5%, respectively. It shows that the encapsulation of the silicon layer can prevent the dissolution of water-soluble PAA.

Example 19

Mesoporous silicon loaded with carbon dots: Dissolve 1 g of citric acid hydrate and 2 g of urea in 10 mL of deionized water, then add 0.25 g of aminated mesoporous silicon (NH ₂ -MSN-q), particle size 5 μm, purchased from Xi’an Qiyue Biotechnology Co., Ltd.), heat in an oven at 180°C for 4 hours, then cool naturally to room temperature, centrifuge to separate the mesoporous silicon, wash with deionized water and ethanol three times, and dry in an oven at 80°C to obtain loaded carbon dots mesoporous silicon DMSN/CDs.

Silicon layer encapsulation: Disperse 0.2g DMSN/CDs in 30mL water and ultrasonically disperse for 30min. Then 3 mL of ammonia water was added to provide an alkaline environment. After the system was heated to 45° C., a mixture of 6 mL LTEOS and 35 mL of ethanol was added dropwise, and the reaction was stirred at 45° C. for 12 hours. After centrifugation, the precipitate was washed three times with water and ethanol respectively, and dried to obtain mesoporous silicon (SiO ₂ @DMSN/CDs) encapsulated by silica. In this embodiment, the stirring speed is 400 rpm.

In the prepared SiO ₂ @DMSN/CDs, the mass percentage of carbon dots in DMSN/CDs is 10%, and the thickness of the silicon dioxide layer is 15nm. At room temperature, DMSN/CDs and SiO ₂ @DMSN/CDs were respectively soaked in distilled water, stirred for 10 days and then centrifuged to determine the loss rate of CDs, which were 40% and 0.2%, respectively. It shows that the encapsulation of the silicon layer can prevent the loss of water-soluble CDs.

Example 20

Add 1 g of mesoporous silicon MSN-4 into a n-hexane solution containing 2 g of inorganic perovskite nanocrystals (CsPbBr ₃ , Xi’an Qiyue Biotechnology Co., Ltd.), stir for 1 hour, then centrifuge and dry to obtain CsPbBr ₃ -loaded mesoporous silicon DMSN/CsPbBr ₃ .

Silicon layer encapsulation: Disperse 0.2 g of DMSN/ _CsPbBr3 in 30 mL of water and stir for 5 min. Then 30 mL of isopropanol solution of PVP with a mass fraction of 1.2% was added. Add 5mL of ammonia to provide an alkaline environment. Finally, a mixture of 3 mL LTEOS and 30 mL isopropanol was added dropwise, and the reaction was stirred at room temperature for 24 h. Centrifuge, wash the precipitate three times with water and ethanol, and dry to obtain mesoporous silicon (SiO _{2 @DMSN/CsPbBr 3 ) encapsulated in silica (SiO 2} @DMSN/CsPbBr ₃ ). The stirring speed in this example is 400rpm electromagnetic stirring.

In the prepared SiO ₂ @DMSN/CsPbBr ₃ , the mass percentage of CsPbBr ₃ in DMSN/CsPbBr ₃ is 50%, and the thickness of the silicon dioxide layer is 30nm. The samples of DMSN/CsPbBr ₃ and SiO ₂ @DMSN/CsPbBr ₃ were soaked in water respectively, and the changes of their fluorescence intensity with soaking time were observed. It was found that SiO ₂ @DMSN/CsPbBr ₃ kept bright green fluorescence and the fluorescence intensity hardly decreased after being placed in water for 7 days; while the green fluorescence of DMSN/CsPbBr ₃ completely disappeared after 1 hour, indicating that DMSN/CsPbBr ₃ without silicon layer encapsulated, adsorbed on the pores The CsPbBr ₃ in the channel is easily decomposed by water, and after the silicon layer is encapsulated, the water in the environment is blocked from contacting the CsPbBr ₃ , which can prevent the CsPbBr ₃ from being decomposed.

The structural and performance characterization method of silicon spheres in the present invention:

1. Particle surface morphology analysis and element energy spectrum analysis:

The morphology of the prepared particles was characterized by scanning electron microscope (SEM, Regulus8100, Hitachi, Japan). Before SEM characterization, all the samples to be tested were treated with gold plating for 60 s under the protection of argon to enhance the conductivity of the samples. In the test, under the conditions of accelerating voltage of 5kV and working distance of 10-15mm, the morphology was observed at 5-10k magnification. See Figures 1, 7, 8 and 14.

The morphology of the nanoparticles was further observed by a transmission electron microscope (TEM, JEM-2100F, Hitachi, Japan) at 200 kV, and elemental mapping images were obtained on an energy dispersive X-ray spectrometer (EDX). See Figures 1, 3, 7, 8, 10 and 14.

2. Fourier transform infrared (FTIR) analysis:

A Fourier transform infrared spectrometer (FTIR, Bio-Rad3000, USA) was used to analyze the composition of the functional groups on the surface of the sample, the scanning range was set to 400-4000cm ^-1 , and the number of scans was set to 32 times. The particles were mixed with potassium bromide, ground to a fine powder and made into round pellets for testing. See Figures 2 and 9.

3. Photocatalytic Activity Test of Loaded Inorganic Absorbent Particles

The photocatalytic activity of the nanoparticles was evaluated by the degradation of aqueous methyl orange solution. Add 0.08 g of particles into 80 mL of methyl orange aqueous solution with an initial concentration _C of 20 mg/L, and stir in the dark for 30 min to reach adsorption equilibrium. A UVB lamp (302nm, 8w) was used to irradiate from above the methyl orange aqueous solution, and at intervals, 1.5 mL of suspension was collected from the solution, and centrifuged to obtain a supernatant. The degradation of methyl orange was monitored by the change of the absorption intensity at 465nm of the maximum absorption peak of methyl orange. Calculate the concentration C of methyl orange using the standard calibration curve. See Figures 4 and 5.

4. Organic absorbent release test

Disperse the particles loaded with organic absorbent in equal volume ratio of PBS and ethanol, put them into a dialysis bag, and put them into a container filled with equal volume ratio of PBS and ethanol. Incubate in a shaker at 150rpm and take samples periodically to test the release profile of the organic absorbent. Evaluate whether there is loss of load during particle storage, that is, storage stability. See Figure 11.

5. Mechanical Stability Test of Loaded Inorganic Absorbent Particles

The mechanical stability of the particles was tested by the retention of the shielding effect of the silica shell on the photocatalysis of the particles. Grind in a mortar for 5 minutes, press at a pressure of 20 MPa for 5 minutes, disperse the particles in ethanol and mechanically stir at a rate of 250 rpm (Shanghai Lichen Instrument Technology Co., Ltd., model LC-CES-120S, stirring speed 60-2000 rpm, power 120W) for 30 minutes, add the treated particles to 80 mL of methyl orange aqueous solution with an initial concentration C _of 20 mg/L, and stir in the dark for 30 minutes to reach adsorption equilibrium. A UVB lamp (302nm, 8w) was used to irradiate from above the methyl orange aqueous solution, and at intervals, 1.5 mL of suspension was collected from the solution, and centrifuged to obtain a supernatant. The degradation of methyl orange was monitored by the change of the absorption intensity at 465nm of the maximum absorption peak of methyl orange. Calculate the concentration C of methyl orange using the standard calibration curve. See Figure 5.

6. Mechanical stability test of loaded organic absorbent particles

The mechanical stability of the particles was tested by different treatments: grinding in a mortar for 5 min, pressing at a pressure of 20 MPa for 5 min, mechanical stirring at 250 rpm for 5 min after dispersion in ethanol. After the treatment, the particles were dispersed in ethanol, and after centrifugation, the concentration of the organic absorbent in the ethanol was measured with an ultraviolet spectrometer, and the retention rate of the organic absorbent in the particles was calculated. See Table 2.

7. UV shielding performance test of sunscreen (agent)

Add 80 mL of 20 mg/L methyl orange aqueous solution into a 100 mL beaker, then add 0.08 _{g of} TiO nanoparticles as photocatalyst, and stir in the dark for 30 min. A glass slide coated with sunscreen (2mg/cm ² ) was covered on the top of the beaker, and a UV lamp (302nm, 8w) was irradiated at 10cm above to initiate the photocatalytic degradation of methyl orange by TiO ₂ . At intervals, 1.5 mL of the methyl orange solution was collected from each beaker and centrifuged to obtain the supernatant. The absorbance of methyl orange was measured at the maximum absorption peak (465 nm). Calculate the concentration of methyl orange using a standard calibration curve. At the same time, take pictures to record the color of the supernatant, and reflect the concentration change of the methyl orange solution through the change of depth. See Figures 6 and 13.

UV protection performance of sunscreens and photostability of sunscreens were further tested with UV intensity sensor cards. Cover the glass sheet coated with sunscreen on the ultraviolet intensity sensor card, and irradiate it at 10cm above with UVB/UVA ultraviolet lamp (302/364nm, 8w). Observe the color change of the card every once in a while, and take pictures to record. After 24 hours of irradiation, observe the UV-sensitive card and take pictures. The intensity of ultraviolet light is reflected by the depth of the color of the card. See Figures 15 and 16.

8. Skin permeability test of loaded organic absorbent particles

Purchase fresh pig skin from a local market, carefully remove the subcutaneous fat with a scalpel, and cut the skin sample into 2 cm diameter circles and store at -20 °C. Skin samples were thawed at room temperature and soaked in PBS for 1 hr before the experiment. Configure PBS-ethanol solution (V/V=1:1) as the receiving solution, and disperse the sample particles (1 mg/mL) as the diffusion solution. During the test, the prepared pigskin was placed between the diffusion cell and the receiving cell, and the diffusion liquid and the receiving liquid were added to the diffusion cell and the receiving cell respectively. The receiver cell was stirred at 400 rpm at 35 °C throughout the experiment. At regular intervals, collect 1 mL of receiving solution from the receiving pool and add 1 mL of fresh receiving solution. The change of the content of the organic absorbent in the receiving liquid with time was detected by ultraviolet-visible spectroscopy, and the concentration of the organic absorbent was calculated using the standard calibration curve. And further calculate the cumulative permeability of the organic absorbent according to the formula (1).

Among them, C _t represents the organic absorbent concentration (μg/mL) measured at the t-th sampling point, C _i represents the organic absorbent concentration (μg/mL) at the t-1 sampling point, V _t and V _i represent the receiving chamber and sampling volume (mL), which are 18 mL and 1 mL in this experiment. A represents the effective skin penetration area, which is 1.13 cm ² in this experiment. See Figure 12.

The disclosed embodiments are described to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A silica-encapsulated object-loaded mesoporous silicon, characterized in that it comprises mesoporous silicon, a load and a silicon dioxide layer, wherein the load is loaded in the pores of the mesoporous silicon, and the outer surface encapsulates a solid silicon dioxide layer with a thickness >= 10nm, and the particle diameter of the mesoporous silicon is greater than 150nm. 2 . The silica-encapsulated loaded mesoporous silicon according to claim 1 , wherein the loaded material is an inorganic nanoparticle or an organic or inorganic solid that is dried and precipitated from a solution. 3 . 3 . The silica-encapsulated carrier-loaded mesoporous silicon according to claim 2 , wherein the inorganic nanoparticles or inorganic solids are one or more of metals, metal oxides or non-metallic inorganic substances. 4 . 4 . The silica-encapsulated carrier-loaded mesoporous silicon according to claim 3 , wherein the metal oxide is an inorganic sunscreen. 5 . The silica-encapsulated loaded mesoporous silicon according to claim 2 , wherein the organic matter is a water-insoluble organic matter. 6 . The silica-encapsulated loaded mesoporous silicon according to claim 5 , wherein the water-insoluble organic matter is an organic sunscreen. 7 . The silica-encapsulated loaded mesoporous silicon according to claim 4 or 6, characterized in that the loading amount of the inorganic sunscreen or organic sunscreen accounts for 10-50% of the mass of the loaded mesoporous silicon. 8. A method for preparing the silica-encapsulated loaded mesoporous silicon according to any one of claims 1-7, characterized in that it comprises the following steps: (1) Preparation of loaded mesoporous silicon by in-situ loading method, comprising the following steps: Dispersing the mesoporous silicon and the precursor in a solvent, or dispersing the mesoporous silicon in a solvent, adding the precursor, or dispersing the precursor in a solvent, adding the mesoporous silicon; stirring, centrifuging, washing, drying, and high-temperature calcination to obtain the loaded mesoporous silicon loaded with inorganic nanoparticles; Or, disperse the mesoporous silicon and the precursor in the solvent, stir, then evaporate the solvent at high temperature until the evaporation is complete, and finally calcine at high temperature to obtain the loaded mesoporous silicon loaded with inorganic nanoparticles; Or, disperse the mesoporous silicon in the solvent, add the precursor, stir, add hydrogen peroxide to the reaction solution, adjust the pH, continue to stir, centrifuge, wash, dry, and calcinate at high temperature to obtain the loaded mesoporous silicon loaded with inorganic nanoparticles; Or, disperse the precursor in a solvent, add mesoporous silicon, heat at high temperature, then naturally cool to room temperature, centrifuge, wash, and dry to obtain loaded mesoporous silicon loaded with inorganic substances; Or, the preparation of loaded mesoporous silicon by physical loading includes the following steps: In a closed reaction vessel, disperse the organic matter in the solvent, add mesoporous silicon, stir in a dark environment, then open the reaction vessel and continue stirring until the solvent is completely evaporated, and the organic matter-loaded mesoporous silicon is obtained; Or, disperse the organic matter in a solvent, add mesoporous silicon, stir, centrifuge, wash, and dry to obtain the loaded mesoporous silicon loaded with organic matter; Or, disperse the inorganic matter in the solvent, add mesoporous silicon, stir, centrifuge, and dry to obtain the loaded mesoporous silicon loaded with inorganic matter; (2) A method for encapsulating silicon dioxide, comprising the following steps: adding a precursor component of silicon dioxide to an aqueous dispersion of loaded mesoporous silicon, stirring, centrifuging to obtain a solid product, washing, and drying to obtain loaded mesoporous silicon encapsulated by silicon dioxide. 9. An application of silica-encapsulated loaded mesoporous silicon in the preparation of coatings, skin care products, flame-retardant or sunscreen fabrics, characterized in that the silica-encapsulated loaded mesoporous silicon is used to prepare emulsions, dispersions, solid or semi-solid products. 10. The application of a silica-encapsulated load-carrying mesoporous silicon according to claim 9 in the preparation of coatings, skin care products, flame-retardant or sunscreen fabrics, characterized in that, when the load is an inorganic sunscreen or an organic sunscreen, the silica-encapsulated load-carrying mesoporous silicon is used to prepare anti-ultraviolet radiation products, and the anti-ultraviolet radiation products include sunscreen products or UV protective coatings for skin.