A TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particles, their preparation method and application

Abstract

The application provides a TiO2@SiO2 core-shell structure nano-multiped sunscreen particle and a preparation method and application thereof. The preparation method comprises the following steps: TiO2 spherical particles are prepared through a sol-gel reaction of a titanium source precursor; a SiO2 shell layer is formed on the surface of the TiO2 spherical particles through a Stöber reaction, so that TiO2@SiO2 core-shell structure particles are obtained; the TiO2@SiO2 core-shell structure particles are dispersed in a PVP-containing emulsion template system, a silicon source precursor is added, and SiO2 is induced to grow on the surface of the particles in a directional manner, so that TiO2@SiO2 core-shell structure nano-multiped particles with multiple SiO2 nano-pedipalps are formed. The application also discloses the nano-multiped sunscreen particle and application thereof in the preparation of a sunscreen composition. The prepared TiO2@SiO2 core-shell structure nano-multiped particles have high ultraviolet shielding capacity and low photocatalytic risk, the SiO2 multiped can improve the interface coverage effect and light path modulation, and improve the emulsion stability.

Description

Technical Field

[0001] This invention relates to the field of sunscreen technology, specifically to a TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particle, its preparation method, and its application. Background Technology

[0002] As the body's largest barrier organ, the skin is the primary target of electromagnetic radiation. Extensive basic research indicates that prolonged sun exposure is a key environmental factor inducing photoaging and various skin tumors, with ultraviolet (UV) radiation considered a major driver of photodamage. Within the UV spectrum, UVB has higher energy and is primarily absorbed by the epidermis and stratum corneum, leading to erythema, sunburn, and keratinocyte apoptosis and abnormal proliferation, easily causing acute sunburn and photoinduced skin cancer. UVA has a longer wavelength and stronger penetrating power, reaching the dermis and causing photoaging phenomena such as wrinkles and pigmentation.

[0003] Currently, sunscreen systems in practical applications are divided into organic and inorganic sunscreens. Organic sunscreens primarily absorb ultraviolet photons through molecular energy level transitions, achieving high UV protection while maintaining high visibility and a lightweight feel in formulations, and still dominate the global commercial sunscreen market. However, numerous in vitro and in vivo studies have shown that organic sunscreens are mostly lipid-soluble small molecules, posing risks of skin penetration and systemic exposure. Furthermore, extensive environmental monitoring studies indicate that organic sunscreens are widely present in seawater, posing environmental and ecological risks.

[0004] Inorganic sunscreens, represented by inorganic oxides such as TiO2 and ZnO, primarily achieve UV protection through mechanisms such as intrinsic band gap absorption, micro / nano structure photoresponse, and multi-interface reflection. Due to their excellent photostability and extremely low skin permeability, inorganic sunscreens are widely used in children's sunscreens and formulas for sensitive skin. TiO2, with its high refractive index and excellent UV absorption capacity, is widely used in inorganic sunscreens. However, it may exhibit photocatalytic activity under UV irradiation, leading to degradation of organic components or pigments in the formula and posing a risk of irritation. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particle, its preparation method, and its application, which reduces the photocatalytic activity of TiO2 while maintaining its UV protection capability.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing TiO2@SiO2 core-shell structured nano-sized multi-legged sunscreen particles, comprising the following steps: S1. Preparation of TiO2 spherical particles: TiO2 spherical particles were prepared by sol-gel reaction of titanium source precursor in alcohol-nitrile-water system. S2, Coating with SiO2 shell: The TiO2 spherical particles obtained in step S1 are dispersed in an alcohol-water-ammonia system. After adding a silicon source precursor, a SiO2 shell is formed on the surface of the TiO2 spherical particles through the Stöber reaction, resulting in TiO2@SiO2 core-shell structured particles. S3. Growth of SiO2 nano-legged particles: The TiO2@SiO2 core-shell structured particles obtained in step S2 are dispersed in an emulsion template system containing PVP. A silicon source precursor is added to induce the directional growth of SiO2 on the particle surface, forming TiO2@SiO2 core-shell structured nano-legged particles with multiple SiO2 nano-legged particles.

[0008] As some specific embodiments of the present invention, in step S1, the titanium source precursor is selected from at least one of isopropyl titanate and tetrabutyl titanate. And / or, the alcohol-nitrile-water system is a mixed system composed of methanol, acetonitrile and water, with a volume ratio of 150-260:50-80:1; And / or, the volume ratio of the titanium source precursor to the mixed alcohol-nitrile-water system is 1:60-250.

[0009] As some specific embodiments of the present invention, in step S1, the reaction system of the sol-gel reaction further includes alkylamines, wherein the alkylamines include dodecylamine.

[0010] Furthermore, in the reaction system, the volume ratio of the titanium source precursor to dodecylamine is 1:1-1.8.

[0011] Specifically, step S1 includes mixing methanol, acetonitrile, deionized water and dodecaneamine, adding a certain amount of phthalate ester precursor and reacting for 12-30 h, followed by centrifugation and washing to obtain TiO2 particles.

[0012] As some specific embodiments of the present invention, in step S2 and / or step S3, the silicon source precursor is selected from at least one of tetramethoxysilane, tetraethoxysilane (ethyl silicate), and methyltrimethoxysilane.

[0013] As some specific embodiments of the present invention, in step S2, the alcohol-water-ammonia system is a mixed system composed of ethanol, water and ammonia, with a volume ratio of 15-35:2-10:0.2-1.5.

[0014] As some specific embodiments of the present invention, in step S2, the mass ratio of the silicon source precursor to the TiO2 spherical particles obtained in step S1 is 0.5-8:1.

[0015] Specifically, in step S2, TiO2 spherical particles are dispersed in an ethanol-water-ammonia system, silicon source precursor is added dropwise and reacted for 2-8 h, and TiO2@SiO2 core-shell structured particles are obtained by centrifugation and washing.

[0016] As some specific embodiments of the present invention, in step S3, the emulsion template system further includes ethanol, water and PVP / pentanol, wherein the volume ratio of ethanol, water and PVP / pentanol is 10-40:1:120-300.

[0017] As some specific embodiments of the present invention, the reaction in step S3 is carried out in the presence of citrate and ammonia, wherein the volume ratio of the citrate solution to the ammonia is 1:1-4. And / or, the reaction time for step S3 is 0.5-6 h.

[0018] As some specific embodiments of the present invention, the concentration of the citrate solution is 4-8 wt.%, preferably 5 wt%, and the concentration of the ammonia water is 25-35 wt.%, preferably 30 wt.

[0019] Specifically, step S3 includes: adding TiO2@SiO2 aqueous dispersion, citrate, ammonia and ethyl silicate sequentially to an ethanol-water-pentanol solution containing PVP for reaction. After reacting for 0.5-6 h, centrifugation and washing are performed to obtain TiO2@SiO2 core-shell structured nanoparticles.

[0020] Step S3 involves forming an emulsion droplet of “internal phase (citrate-water-ammonia)-external phase (pentanol)-interfacial phase (PVP)” in a pentanol system containing PVP. Ethyl silicate enters from the external phase and undergoes hydrolysis and condensation within the emulsion droplet, inducing the directional growth of SiO2 on the particle surface to form a nano-peregrine structure.

[0021] This invention uses a sol-gel system of methanol, deionized water, dodecylamine, acetonitrile, and tetraisopropyl titanate to prepare TiO2 seed particles; through a modified Stöber reaction, core-shell structured microspheres of TiO2 coated with a SiO2 thin shell of controllable thickness are obtained to suppress the photocatalytic activity of TiO2 and provide a uniform interface for subsequent anisotropic growth; in a water / pentanol system containing polyvinylpyrrolidone, citrate, ammonia, and ethyl silicate are introduced to form an emulsion droplet template, so that SiO2 is directionally grown on the particle surface into a nano-multi-legged structure, thus obtaining TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particles.

[0022] Secondly, the present invention provides TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particles, which are prepared by the preparation method described in any of the above claims.

[0023] As some specific embodiments of the present invention, the TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particles include a TiO2 core, a SiO2 shell covering the outside of the TiO2 core, and multiple SiO2 nano-legs grown on the outer surface of the shell.

[0024] In some specific embodiments of the present invention, the thickness of the SiO2 shell layer in the TiO2@SiO2 core-shell structured particles is 20-200 nm. The shell thickness is adjusted by the amount of silicon source precursor used.

[0025] As some specific embodiments of the present invention, each TiO2@SiO2 core-shell structured nanoparticle has 3-20 SiO2 nanoparticles, preferably 8-14.

[0026] Thirdly, the present invention provides the use of TiO2@SiO2 core-shell structured nano-legged sunscreen particles as described in any of the preceding claims in the preparation of sunscreen compositions, wherein the composition is an O / W emulsion or a spray emulsion, and the TiO2@SiO2 core-shell structured nano-legged sunscreen particles, as inorganic ultraviolet protectants, are added to the sunscreen composition in an amount of 0.1-20 wt%.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1) The multi-legged sunscreen particles prepared by this invention can achieve both UV protection and low photocatalytic risk. The TiO2 core provides UV protection; the surface SiO2 shell inhibits the contact between the core and the outside world and reduces photocatalytic side reactions, while providing a controllable interface for uniform multi-legged growth.

[0028] 2) The multi-legged sunscreen particles prepared by this invention, under the condition of photocatalysis inhibition by the SiO2 shell, improve the interface coverage effect and light path modulation through the multi-legged SiO2, thereby achieving ultraviolet protection. They can be applied to the field of ultraviolet light protection with low photocatalytic activity.

[0029] 3) The multi-legged sunscreen particles of the present invention are a sunscreen safety structure with TiO2 as the ultraviolet protection core, and SiO2 shell layer to inhibit photocatalysis and induce SiO2 multi-legged growth for interface coverage and optical path modulation.

[0030] 4) The multi-legged sunscreen particles prepared by the present invention utilize the geometric interlocking and steric hindrance effect generated by the multi-legged structure, making it difficult for the particles to desorb or migrate at the oil / water interface, thereby significantly enhancing the interfacial retention and anti-disturbance ability and improving the stability of the emulsion.

[0031] 5) This invention employs a sol-gel method to prepare TiO2 cores, modified Stöber shells, and emulsion drop templates to induce directional SiO2 leg growth. A two-stage interface preparation route exists: first, a controllable SiO2 shell is obtained using modified Stöber as a homogeneous interface, and then SiO2 legs are grown on this shell using an emulsion drop template. The mechanism of SiO2 multi-leg growth induced by the emulsion drop template is clearly defined as achieving directional growth through an emulsion droplet consisting of an "inner phase (citrate-water-ammonia)-outer phase (pentanol)-interfacial phase (PVP)," combined with low-shear mixing. Attached Figure Description

[0032] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 The image shows a scanning electron microscope (SEM) image of the TiO2@SiO2 core-shell structured multi-legged sunscreen particles prepared in Example 1 at 200x magnification. Figure 2 This is a scanning electron microscope image of the TiO2@SiO2 core-shell structured multi-legged sunscreen particles prepared in Example 2 at 200,000 magnification; Figure 3 This is a scanning electron microscope image of the TiO2@SiO2 core-shell structured multi-legged sunscreen particles prepared in Example 3 at 200,000 magnification; Figure 4 This is a scanning electron microscope image of the TiO2@SiO2 core-shell structured multi-legged sunscreen particles prepared in Example 4 at 200,000 magnification; Figure 5 The image is a scanning electron microscope image of the TiO2@SiO2 core-shell structured particles prepared in Comparative Example 1 at 10,000 magnification. Figure 6 The image is a scanning electron microscope image of TiO2 nano-monopods prepared in Comparative Example 2 at 100,000 magnification. Figure 7 The ultraviolet transmittance spectrum of each sunscreen particle; Figure 8 The photodegradation effect of each sunscreen particle after 3 hours of UV irradiation in a methylene blue solution; Figure 9 The image shows the stability test results of each sunscreen particle in silicone oil-water emulsion after 48 hours. Detailed Implementation

[0033] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0034] Example 1 (1) Add 0.95 mL of isopropyl titanate to a mixed solution of 100 mL of methanol, 0.5 mL of deionized water, 1.2 mL of dodecylamine and 40 mL of acetonitrile. Stir for 24 h, then centrifuge and wash the solution to obtain TiO2 spherical particles.

[0035] (2) Disperse 0.1g of the TiO2 spherical particles prepared in the above steps in 10mL of ethanol. Add 13mL of ethanol, 4.3mL of deionized water and 0.62mL of ammonia to the dispersion, then add 0.345mL of ethyl silicate and stir for 4h. After centrifugation and washing, TiO2@SiO2 core-shell structured particles are obtained.

[0036] (3) Disperse 0.1g of the TiO2@SiO2 core-shell structured particles prepared in the above steps in deionized water. Mix 2mL of ethanol, 100μL of deionized water and 20mL of 10wt% PVP / pentanol solution, then add 300μL of 7.5wt% TiO2@SiO2 aqueous dispersion, 200μL of 0.18M sodium citrate, 400μL of 30wt.% ammonia water and 100μL of ethyl silicate in sequence. After standing for 2h, centrifuge and wash to obtain TiO2@SiO2 core-shell structured nano-multi-legged particles.

[0037] Scanning electron microscope (SEM) images of the samples are as follows Figure 1 The magnification is 200,000 times.

[0038] In this embodiment, the nano-sized multi-legged particles have a particle size of 644 nm, a shell thickness of approximately 122 nm, an average number of multi-legged particles of 10, an average length of 193 nm, and an average root diameter of 156 nm.

[0039] Example 2 (1) Add 0.95 mL of isopropyl titanate to a mixed solution of 100 mL of methanol, 0.5 mL of deionized water, 1.2 mL of dodecylamine and 40 mL of acetonitrile. Stir for 24 h, then centrifuge and wash the solution to obtain TiO2 spherical particles.

[0040] (2) Disperse 0.1g TiO2 particles in 10mL ethanol. Add 13mL ethanol, 4.3mL deionized water and 0.62mL ammonia to the dispersion, then add 0.345mL tetraethyl orthosilicate and stir for 4h. After centrifugation and washing, TiO2@SiO2 core-shell structured particles are obtained.

[0041] (3) Disperse 0.1g of TiO2@SiO2 core-shell structured particles in deionized water. Mix 2mL of ethanol, 100μL of deionized water and 20mL of 10wt% PVP / pentanol solution, then add 300μL of 7.5wt% TiO2@SiO2 aqueous dispersion, 200μL of 0.18M sodium citrate, 480μL of ammonia and 100μL of ethyl silicate. After standing for 2h, centrifuge and wash to obtain TiO2@SiO2 core-shell structured nano-multi-legged particles.

[0042] Scanning electron microscope (SEM) images of the samples are as follows Figure 2 The magnification is 200,000 times.

[0043] In this embodiment, the nano-sized multi-legged particles have a particle size of 644 nm, a shell thickness of approximately 122 nm, an average number of legs of 9, an average leg length of 139 nm, and an average root diameter of 246 nm.

[0044] Example 3 (1) Add 0.95 mL of isopropyl titanate to a mixed solution of 100 mL of methanol, 0.5 mL of deionized water, 1.2 mL of dodecylamine and 40 mL of acetonitrile. Stir for 24 h, then centrifuge and wash the solution to obtain TiO2 spherical particles.

[0045] (2) Disperse 0.1g TiO2 particles in 10mL ethanol. Add 13mL ethanol, 4.3mL deionized water and 0.62mL ammonia to the dispersion, then add 0.345mL tetraethyl orthosilicate and stir for 4h. After centrifugation and washing, TiO2@SiO2 core-shell structured particles are obtained.

[0046] (3) Disperse 0.1g of TiO2@SiO2 core-shell structured particles in deionized water. Mix 2mL of ethanol, 100μL of deionized water and 20mL of 10wt% PVP / pentanol solution, then add 200μL of 7.5wt% TiO2@SiO2 aqueous dispersion, 200μL of 0.18M sodium citrate, 440μL of ammonia and 120μL of ethyl silicate. After standing for 2h, centrifuge and wash to obtain TiO2@SiO2 core-shell structured nano-multi-legged particles.

[0047] Scanning electron microscope (SEM) images of the samples are as follows Figure 3 As shown, the magnification is 200,000 times.

[0048] In this embodiment, the nano-sized multi-legged particles have a particle size of 644 nm, a shell thickness of approximately 122 nm, an average number of multi-legged particles of 18, an average length of 315 nm, and an average root diameter of 143 nm.

[0049] Example 4 (1) Add 0.95 mL of isopropyl titanate to a mixed solution of 100 mL of methanol, 0.5 mL of deionized water, 1.2 mL of dodecylamine and 40 mL of acetonitrile. Stir for 24 h, then centrifuge and wash the solution to obtain TiO2 spherical particles.

[0050] (2) Disperse 0.1g TiO2 particles in 10mL ethanol. Add 13mL ethanol, 4.3mL deionized water and 0.62mL ammonia to the dispersion, then add 0.132mL tetraethyl orthosilicate and stir for 4h. After centrifugation and washing, TiO2@SiO2 core-shell structured particles are obtained.

[0051] (3) Disperse 0.1g of TiO2@SiO2 core-shell structured particles in deionized water. Mix 2mL of ethanol, 100μL of deionized water and 20mL of 10wt% PVP / pentanol solution, then add 300μL of 7.5wt% TiO2@SiO2 aqueous dispersion, 200μL of 0.18M sodium citrate, 400μL of ammonia and 100μL of ethyl silicate. After standing for 2h, centrifuge and wash to obtain TiO2@SiO2 core-shell structured nano-multi-legged particles.

[0052] Scanning electron microscope (SEM) images of the samples are as follows Figure 4 The magnification is 200,000 times.

[0053] In this embodiment, the nano-sized multi-legged particles have a particle size of 576 nm, a shell thickness of approximately 88 nm, an average number of multi-legged particles of 11, an average length of 108 nm, and an average root diameter of 190 nm.

[0054] In this embodiment, the amount of silicon source precursor was adjusted, resulting in a thinner shell layer and a smaller particle size in the core-shell structure. This increased the contact area between the emulsion droplets and the smaller core-shell structure, leading to changes in the multi-legged structure.

[0055] Comparative Example 1 (1) Add 0.95 mL of isopropyl titanate to a mixed solution of 100 mL of methanol, 0.5 mL of deionized water, 1.2 mL of dodecylamine and 40 mL of acetonitrile. Stir for 24 h, then centrifuge and wash the solution to obtain TiO2 spherical particles.

[0056] (2) Disperse 0.1g of the TiO2 spherical particles prepared in the above steps in 10mL of ethanol. Add 13mL of ethanol, 4.3mL of deionized water and 0.62mL of ammonia to the dispersion, then add 0.345mL of ethyl silicate and stir for 4h. After centrifugation and washing, TiO2@SiO2 core-shell structured particles are obtained.

[0057] Scanning electron microscope (SEM) images of the samples are as follows Figure 5 The magnification is 10,000x. In this comparative example, the particle size of the core-shell structure is 644 nm, and the shell thickness is approximately 122 nm.

[0058] Comparative Example 2 In this comparative example, the SiO2 shell is omitted. The specific preparation steps are as follows: (1) Add 2.6 mL of isopropyl titanate to a mixed solution of 100 mL methanol, 0.5 mL deionized water, 1.2 mL dodecylamine and 40 mL acetonitrile. Stir for 24 h, then centrifuge and wash the solution to obtain TiO2 spherical particles.

[0059] (2) Disperse 0.1g of the TiO2 spherical particles prepared in the above steps in deionized water. Mix 2mL of ethanol, 100μL of deionized water and 20mL of 10wt% PVP / pentanol solution and vortex for 1 minute. Then add 300μL of 7.5wt% TiO2 aqueous dispersion, 200μL of 0.18M sodium citrate, 400μL of ammonia and 100μL of ethyl silicate, vortex for 3 minutes, let stand for 2 hours, and then centrifuge and wash to obtain the final product.

[0060] This comparative example omits the step of preparing the SiO2 shell and directly prepares SiO2 nano-pods outside the TiO2 spherical particles.

[0061] Scanning electron microscope (SEM) images of the samples are as follows Figure 6 The magnification is 100,000 times.

[0062] The TiO2 spherical particles prepared in this comparative example have a particle size of 588 nm. Without SiO2 coating, only single-legged SiO2 particles grow, and the uniformity of multi-legged growth decreases.

[0063] Effect Example The TiO2 spherical particles prepared in the first step of each embodiment and comparative example, the TiO2@SiO2 core-shell structured particles prepared in comparative example 1, and the TiO2@SiO2 core-shell structured nano-multi-legged particles prepared in example 1 were subjected to ultraviolet spectroscopy characterization, photocatalytic activity verification experiments, and storage stability experiments, respectively.

[0064] 1. Ultraviolet Transmittance Spectroscopy Test Method: The test was performed according to the method described in the paper DOI: 10.1021 / acs.nanolett.4c04969. Sample Preparation: The particles were transferred onto 3M tape at a concentration of (2.00±0.05) mg / cm³. 2 The sample is weighed and then sandwiched between two pieces of quartz glass to form a "sandwich" structure, which secures the sample and provides a uniform test surface. Measurements are performed using a UV-Vis spectrophotometer equipped with an integrating sphere.

[0065] like Figure 7 The image shows the ultraviolet transmission spectra of TiO2 spherical particles, TiO2@SiO2 core-shell particles in Comparative Example 1, and TiO2@SiO2 multi-legged particles in Example 1.

[0066] As can be seen from the figure, the average UV transmittance of TiO2 nanoparticles is 3.72%, the average UV transmittance of TiO2@SiO2 core-shell particles in Comparative Example 1 is 1.03%, and the average UV transmittance of TiO2@SiO2 multi-legged particles in Example 1 is 1.83%. Compared with TiO2 nanoparticles and TiO2@SiO2 core-shell particles in Comparative Example 1, TiO2@SiO2 multi-legged particles in Example 1 still maintain a lower UV transmittance, indicating that the product of the present invention has a strong sun protection function.

[0067] 2. Methylene blue degradation test: Mix 1 mg of particles with 10 mL of 5 mg / L methylene blue solution, disperse by ultrasonication, and irradiate with ultraviolet light for 3 hours to evaluate photocatalytic activity, because methylene blue will be degraded and faded by reactive oxygen species generated by TiO2 under ultraviolet light.

[0068] like Figure 8 As shown in the figures, from left to right, the images depict the methylene blue degradation results of the particles-free sample, TiO2 nanoparticles, TiO2@SiO2 core-shell particles from Comparative Example 1, and TiO2@SiO2 multi-legged particles from Example 1. The figures show that compared to TiO2 nanoparticles and TiO2@SiO2 core-shell particles from Comparative Example 1, the methylene blue degradation rate of the TiO2@SiO2 multi-legged particles in Example 1 is lower, indicating a significant reduction in photocatalytic effect.

[0069] Compared to Comparative Example 1, the TiO2@SiO2 multi-legged particles in Example 1 can reduce particle aggregation, thus reducing their photocatalytic activity.

[0070] 3. Stability test of silicone oil-water emulsion: Mix silicone oil and water at a volume ratio of 1:1, add different types of particles, homogenize, and observe the layering of the emulsion within 48 hours.

[0071] like Figure 9As shown, the left side displays the TiO2@SiO2 core-shell particles from Comparative Example 1, while the right side displays the silicone oil-water emulsion stability results of the TiO2@SiO2 multi-legged particles from Example 1. The figures show that compared to the complete phase separation of the TiO2@SiO2 core-shell particles in Comparative Example 1, the emulsion stability of the TiO2@SiO2 multi-legged particles in Example 1 is improved. The multi-legged structure generates geometric interlocking and steric hindrance effects, making it difficult for particles to desorb or migrate at the oil / water interface, thus significantly enhancing interface residence and resistance to disturbances.

[0072] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing TiO2@SiO2 core-shell structured nano-pedicled sunscreen particles, characterized in that, Includes the following steps: S1. Preparation of TiO2 spherical particles: TiO2 spherical particles were prepared by sol-gel reaction of titanium source precursor in alcohol-nitrile-water system. S2, Coating with SiO2 shell: The TiO2 spherical particles obtained in step S1 are dispersed in an alcohol-water-ammonia system. After adding a silicon source precursor, a SiO2 shell is formed on the surface of the TiO2 spherical particles through the Stöber reaction, resulting in TiO2@SiO2 core-shell structured particles. S3. Growth of SiO2 nano-legged particles: The TiO2@SiO2 core-shell structured particles obtained in step S2 are dispersed in an emulsion template system containing PVP. A silicon source precursor is added to induce the directional growth of SiO2 on the particle surface, forming TiO2@SiO2 core-shell structured nano-legged particles with multiple SiO2 nano-legged particles.

2. The preparation method according to claim 1, characterized in that, In step S1, the titanium source precursor is selected from at least one of isopropyl titanate and tetrabutyl titanate. And / or, the alcohol-nitrile-water system is a mixed system composed of methanol, acetonitrile and water, with a volume ratio of 150-260:50-80:1; And / or, the volume ratio of the titanium source precursor to the alcohol-nitrile-water system is 1:60-250.

3. The preparation method according to claim 1, characterized in that, In step S1, the reaction system of the sol-gel reaction also includes alkylamines, including dodecylamine.

4. The preparation method according to claim 1, characterized in that, In step S2 and / or step S3, the silicon source precursor is selected from at least one of tetramethoxysilane, tetraethoxysilane, and methyltrimethoxysilane.

5. The preparation method according to claim 1, characterized in that, In step S2, the alcohol-water-ammonia system is a mixed system composed of ethanol, water and ammonia, with a volume ratio of 15-35:2-10:0.2-1.

5. And / or, in step S2, the mass ratio of the silicon source precursor to the TiO2 spherical particles obtained in step S1 is 0.5-8:

1.

6. The preparation method according to claim 1, characterized in that, In step S3, the emulsion template system further includes ethanol, water, and PVP / pentanol, wherein the volume ratio of ethanol, water, and PVP / pentanol is 10-40:1:120-300.

7. The preparation method according to claim 1, characterized in that, The reaction in step S3 is carried out in the presence of citrate and ammonia, wherein the volume ratio of the citrate solution to the ammonia is 1:1-4. And / or, the reaction time for step S3 is 0.5-6 h.

8. A TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particle, characterized in that, The TiO2@SiO2 core-shell structured nano-footed sunscreen particles are prepared by the preparation method described in any one of claims 1-7. The particles include a TiO2 core, a SiO2 shell covering the TiO2 core, and multiple SiO2 nanofooted particles grown on the outer surface of the shell.

9. The TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particles according to claim 8, characterized in that, In the TiO2@SiO2 core-shell structured particles, the thickness of the SiO2 shell layer is 20-200 nm; And / or, in the TiO2@SiO2 core-shell structured nanoparticles, each particle has 3-20 SiO2 nanoparticles.

10. The use of TiO2@SiO2 core-shell structured nanoparticles as described in claim 8 or 9 in the preparation of sunscreen compositions, characterized in that, The composition is an O / W emulsion or a spray emulsion, and the TiO2@SiO2 core-shell structured nano-multi-legged sunscreen particles are used as inorganic UV protectants, with an addition amount of 0.1-20 wt% in the sunscreen composition.

Images