A method for preparing self-recessed micro-nanostructured hollow silica spheres

Abstract

The present invention discloses a method for preparing hollow silica spheres with self-recessed micro-nano structures, comprising the following steps: S1, sequentially adding acetonitrile and aqueous ammonia to ethanol, stirring for reaction, adding glucose and EDTA, stirring and mixing, and performing a hydrothermal reaction to obtain induced carbon spheres; S2, adding induced carbon spheres and aqueous ammonia to a mixed solution of water and ethanol, ultrasonicating, and dropping the mixture into a tetraethyl silicate / ethanol solution, stirring for reaction; S3, heating, and calcining to obtain hollow silica spheres. The present invention uses induced carbon spheres with a special structure as hard templates, wraps a silica layer on the surface of the carbon spheres, and then removes the carbon spheres through calcination to obtain hollow silica spheres with self-recessed micro-nano structures. The hollow silica spheres with this structure not only have excellent structural stability, but can also adsorb air on their surface well, thereby obtaining good super-amphiphobic properties. The preparation method of the present invention has a simple process, strong controllability, is easy to realize large-scale industrial production, and has good practical application prospects.

Description

Technical Field

[0001] The invention relates to the field of super-amphiphobic material synthesis, and in particular to a method for preparing self-recessed micro-nanostructured hollow silicon dioxide spheres. Background Art

[0002] Super-amphiphobic refers to a material surface with a static contact angle of greater than 150° for water and organic liquids, and a rolling angle of less than 10°. This material, which possesses both super-hydrophobic and super-oleophobic properties, is called a super-amphiphobic material. Super-amphiphobic materials have a higher static contact angle with water and a smaller rolling angle, and can repel liquids with lower surface energy in complex environments, such as domestic sewage and oil pollution. They possess advantages in anti-fouling, anti-corrosion, and self-cleaning that super-hydrophobic surfaces cannot match. Therefore, super-amphiphobic materials are more suitable for applications such as building glass exterior walls, automotive glass, oil pipeline drag reduction, waterproofing of electronic devices, self-cleaning wearable devices, and self-cleaning solar cell panels, and are a new material with great development potential.

[0003] However, simply altering the surface tension of ordinary nanomaterials is difficult to achieve an amphiphobic effect. In recent years, researchers, building on their understanding of the unique structure of lotus leaves, which have countless micron-sized papillae, each covered by countless nano-sized papillae, have proposed increasing surface roughness to achieve a super-amphiphobic surface. Research has shown that by constructing different microstructures on the surface of a material, the micro- and nanomaterials can form a complementary microstructure of alternating concave and convex surfaces. Because the nano-sized concave surfaces allow for the presence of adsorbed gases, this macroscopically acts as a stable gas film, preventing direct and complete contact between oil and water, thereby achieving super-amphiphobic properties. To achieve super-amphiphobicity, the micro- and nanostructures on the material surface must possess certain specific characteristics, namely, forming single or double concave structures.

[0004] Currently, the main methods for fabricating surface micro- and nanostructures include self-assembly, photolithography, plasma etching, and deposition. Among these, the most commonly used surface processing method is self-assembly, which involves depositing nanomaterials onto microstructures to create micro- and nanostructures. However, these methods are often complex, costly, and lack controllability, making them infeasible for large-scale fabrication. Furthermore, the resulting micro- and nanostructures can easily fall off, significantly limiting the industrial application of super-amphiphobic materials. Summary of the Invention

[0005] In response to the technical problems existing in the background technology, the purpose of the present invention is to provide a method for preparing self-recessed micro-nanostructured hollow silica spheres. The hollow silica spheres prepared by this preparation method have a micro-nano hybrid structure, can well adsorb air on their surface, and have good super-amphiphobic properties and structural stability.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A first aspect of the present invention provides a method for preparing self-recessed micro-nanostructured hollow silica spheres, comprising the following steps:

[0008] S1. Preparation of induced carbon spheres:

[0009] S11, adding acetonitrile and aqueous ammonia to ethanol in sequence, stirring to react, to obtain solution A;

[0010] S12, adding glucose and EDTA to solution A, stirring and mixing to obtain solution B, placing solution B in a closed reactor, performing a hydrothermal reaction, and obtaining induced carbon spheres;

[0011] S2. Preparation of hollow silica spheres:

[0012] S21, adding the obtained induced carbon spheres to a mixed solution of water and ethanol, uniformly dispersing them by ultrasonication, then adding ammonia water, and continuing ultrasonication to obtain solution B;

[0013] S22, prepare tetraethyl silicate / ethanol solution, add solution B dropwise to the tetraethyl silicate / ethanol solution, and stir to react;

[0014] S23. After the reaction is completed, the mixture is centrifuged and dried, placed under closed conditions, heated, and calcined to obtain hollow silica spheres with self-recessed micro-nano structures.

[0015] Preferably, in step S11, the volume ratio of acetonitrile, ethanol and aqueous ammonia is 35-50:80-170:1-5.

[0016] Preferably, in step S11, the stirring reaction time is 6-12 hours.

[0017] Preferably, in step S12, the volume ratio of solution B, glucose, and EDTA is 5-10 ml: 57-72 mg: 100-150 mg.

[0018] Preferably, in step S12, the temperature of the hydrothermal reaction is 140-180° C., and the hydrothermal reaction time is 8-12 h.

[0019] Preferably, in step S21, the mass volume ratios of the induced carbon spheres, water, ethanol and aqueous ammonia are 3-20 mg:20-30 mL: and 100-120 mL:1-3 mL.

[0020] Preferably, in step S22, the volume ratio of the tetraethyl silicate / ethanol solution to solution A is 26-37:20-35.

[0021] Preferably, in the tetraethyl silicate / ethanol solution, the mass ratio of tetraethyl silicate to ethanol is 8:18-29.

[0022] Preferably, in step S22, the dropping speed is 1-2 mL / h.

[0023] Preferably, in step S22, the stirring reaction time is 10-18 hours.

[0024] Preferably, in step S23, the heating rate is 5-8°C / min, the calcination temperature is 400-600°C, and the calcination time is 2-6h.

[0025] The second aspect of the present invention is to provide a hollow silica sphere with a self-recessed micro-nano structure obtained by the above preparation method.

[0026] The present invention has the following beneficial effects:

[0027] (1) In the selection of a hard template, the present invention creatively synthesizes a special structure-induced carbon sphere as a hard template, coats the surface of the carbon sphere with a silicon dioxide layer, and finally removes the carbon sphere by calcination to obtain a silicon dioxide hollow sphere with a self-depressed, dried plum morphology. The silicon dioxide hollow sphere with this structure relies on its own depression to form a micro-nano hybrid structure on its surface, thus having excellent structural stability. In addition, this micro-nano hybrid structure increases the roughness of the sphere surface, which can effectively adsorb air on its surface, thereby achieving excellent super-amphiphobic properties.

[0028] (2) The preparation method of the present invention has simple process and strong controllability, is easy to realize large-scale industrial production and application, and has good practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is an SEM image of the self-recessed micro-nanostructured hollow silica spheres prepared in Example 1;

[0031] Figure 2 TEM image of the self-recessed micro-nanostructured hollow silica spheres prepared in Example 1;

[0032] Figure 3 The SEM and TEM images of the self-recessed micro-nanostructured hollow silica spheres prepared in Example 2 are shown;

[0033] Figure 4 The SEM and TEM images of the hollow silica spheres prepared in Comparative Example 1 are shown;

[0034] Figure 5 The SEM and TEM images of the hollow silica spheres prepared in Comparative Example 2 are shown;

[0035] Figure 6 The SEM and TEM images of the hollow silica spheres prepared in Comparative Example 3 are shown;

[0036] Figure 7 These are the SEM and TEM images of the hollow silica spheres prepared in Comparative Example 4. DETAILED DESCRIPTION

[0037] In the following description, specific details such as specific system structures and technologies are provided for the purpose of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may also be implemented in other embodiments without these specific details.

[0038] Example 1

[0039] A method for preparing self-recessed micro-nanostructured hollow silica spheres, comprising the following steps:

[0040] S1. Preparation of induced carbon spheres:

[0041] S11, add 40 mL of acetonitrile to 150 mL of ethanol, stir and mix for 8 minutes, then add 2.4 mL of ammonia water, and continue stirring for 10 hours to obtain solution A;

[0042] S12. Add 8 ml of solution A to 35 ml of 0.1 mol / L glucose solution, stir for 25 min, add 100 mg of EDTA and continue stirring for 50 min to obtain solution B. Then, place solution B in a closed reactor and perform hydrothermal reaction at 180° C. for 8 h. After the reaction, centrifuge and wash to obtain (special structure) induced carbon spheres;

[0043] S2. Preparation of hollow silica spheres:

[0044] S21, adding the obtained induced carbon spheres to a mixed solution of 30 mL of water and 120 mL of ethanol, ultrasonicating for 10 min, then adding 2.0 mL of ammonia water, and continuing ultrasonicating for 10 min to obtain solution B;

[0045] S22, prepare a tetraethyl silicate / ethanol solution in a ratio of 8 parts of tetraethyl silicate to 20 parts of ethanol, add solution B dropwise to the prepared tetraethyl silicate / ethanol solution, and stir to react;

[0046] S23. After the reaction is completed, the reaction product is centrifuged and dried, and then heated to 480°C in a muffle furnace at a heating rate of 5°C / min and calcined for 2h to obtain self-recessed micro-nanostructured silica hollow spheres.

[0047] Example 2

[0048] A method for preparing self-recessed micro-nanostructured hollow silica spheres, comprising the following steps:

[0049] S1. Preparation of induced carbon spheres:

[0050] S11, add 40 mL of acetonitrile to 150 mL of ethanol, stir and mix for 10 minutes, then add 2 mL of ammonia water, and continue stirring for 10 hours to obtain solution A;

[0051] S12. Add 8 ml of solution A to 35 ml of 0.1 mol / L glucose solution, stir for 25 min, add 150 mg of EDTA and continue stirring for 40 min to obtain solution B. Then, place solution B in a closed reactor and perform hydrothermal reaction at 160° C. for 12 h. After the reaction, centrifuge and wash to obtain (special structure) induced carbon spheres;

[0052] S2. Preparation of hollow silica spheres:

[0053] S21, adding the obtained induced carbon spheres to a mixed solution of 30 mL of water and 110 mL of ethanol, ultrasonicating for 10 min, then adding 1.5 mL of ammonia water, and continuing ultrasonicating for 10 min to obtain solution B;

[0054] S22, prepare a tetraethyl silicate / ethanol solution in a ratio of 8 parts of tetraethyl silicate to 25 parts of ethanol, add solution B dropwise to the prepared tetraethyl silicate / ethanol solution, and stir to react;

[0055] S23. After the reaction is completed, the reaction product is centrifuged and dried, and then heated to 500° C. at a heating rate of 5° C. / min in a muffle furnace and calcined for 2 h to obtain self-recessed micro-nanostructured silica hollow spheres.

[0056] Example 3

[0057] A method for preparing self-recessed micro-nanostructured hollow silica spheres, comprising the following steps:

[0058] S1. Preparation of induced carbon spheres:

[0059] S11, add 45 mL of acetonitrile to 80 mL of ethanol, stir and mix for 10 min, then add 2 mL of ammonia water, and continue stirring for 6 h to obtain solution A;

[0060] S12. Add 5 ml of solution A to 40 ml of 0.1 mol / L glucose solution, stir for 20 min, add 100 mg of EDTA and continue stirring for 30 min to obtain solution B. Then, place solution B in a closed reactor and perform hydrothermal reaction at 140°C for 8 h. After the reaction, centrifuge and wash to obtain (special structure) induced carbon spheres;

[0061] S2. Preparation of hollow silica spheres:

[0062] S21, adding the obtained induced carbon spheres to a mixed solution of 20 mL of water and 100 mL of ethanol, ultrasonicating for 10 min, then adding 1.2 mL of ammonia water, and continuing ultrasonicating for 10 min to obtain solution B;

[0063] S22, prepare a tetraethyl silicate / ethanol solution in a ratio of 8 parts tetraethyl silicate to 18 parts ethanol, add solution B dropwise to the prepared tetraethyl silicate / ethanol solution, and stir to react;

[0064] S23. After the reaction is completed, the reaction product is centrifuged and dried, and then heated to 450°C in a muffle furnace at a heating rate of 5°C / min and calcined for 2h to obtain self-recessed micro-nanostructured silica hollow spheres.

[0065] Example 4

[0066] A method for preparing self-recessed micro-nanostructured hollow silica spheres, comprising the following steps:

[0067] S1. Preparation of induced carbon spheres:

[0068] S11, adding 35 mL of acetonitrile to 140 mL of ethanol, stirring and mixing for 8 minutes, then adding 2 mL of ammonia water, and continuing to stir for 10 hours to obtain a solution A containing a nitrogen-containing structural inducer;

[0069] S12. Add 10 ml of solution A to 40 ml of 0.1 mol / L glucose solution, stir for 20 min, add 150 mg of EDTA and continue stirring for 30 min to obtain solution B. Then, place solution B in a closed reactor and perform hydrothermal reaction at 160° C. for 8-12 h. After the reaction, centrifuge and wash to obtain (special structure) induced carbon spheres;

[0070] S2. Preparation of hollow silica spheres:

[0071] S21, adding the obtained induced carbon spheres to a mixed solution of 30 mL of water and 100 mL of ethanol, ultrasonicating for 10 min, then adding 2 mL of ammonia water, and continuing ultrasonicating for 10 min to obtain solution B;

[0072] S22, prepare a tetraethyl silicate / ethanol solution in a ratio of 8 parts of tetraethyl silicate to 20 parts of ethanol, add solution B dropwise to the prepared tetraethyl silicate / ethanol solution, and stir to react;

[0073] S23. After the reaction is completed, the reaction product is centrifuged and dried, and then heated to 480°C in a muffle furnace at a heating rate of 5°C / min and calcined for 2h to obtain self-recessed micro-nanostructured silica hollow spheres.

[0074] Comparative Example 1

[0075] The steps are basically the same as those in Example 1, except that "100 mg of EDTA" in step S12 is replaced by "75 mg of EDTA".

[0076] Comparative Example 2

[0077] The steps are basically the same as those in Example 1, except that the amount of ammonia water in step S11 is replaced from "2 ml" to "4 ml".

[0078] Comparative Example 3

[0079] The steps are basically the same as those of Comparative Example 1, except that the amount of ammonia water in step S11 is replaced from "2 ml" to "4 ml".

[0080] Comparative Example 4

[0081] The steps are basically the same as those in Comparative Example 2, except that "100 mg of EDTA" in step S12 is replaced by "150 mg of EDTA".

[0082] The morphology of the hollow silica spheres with self-recessed micro-nanostructures obtained in Examples 1-2 and the hollow silica spheres obtained in Comparative Examples 1-4 was characterized. Figure 1-7 .

[0083] Depend on Figure 1-2 The results show that the hollow silica spheres prepared in Examples 1-2 of the present invention exhibit a unique, self-recessed micro-nanostructured hollow structure. These hollow silica spheres, with this structure, rely on their own recesses to form a micro-nano hybrid structure on their surface. In contrast, the hollow microspheres prepared in Comparative Examples 1-4 did not form a recessed micro-nano hybrid structure.

[0084] The present invention is not limited to the above-mentioned specific implementation methods. Various changes made by ordinary technicians in this field based on the above-mentioned concept without creative work are all within the scope of protection of the present invention.

Claims

1. A method for preparing self-recessed micro-nanostructured hollow silica spheres, characterized in that: The following steps are involved: S1. Preparation of induced carbon spheres: S11, preparing a nitrogen-containing structural inducer: adding acetonitrile and aqueous ammonia to ethanol in sequence, stirring to react, to obtain a solution A containing a nitrogen-containing structural inducer; S12, preparing induced carbon spheres: adding glucose and EDTA to solution A, stirring and mixing to obtain solution B, placing solution B in a closed reactor, and performing a hydrothermal reaction to obtain induced carbon spheres; S2. Preparation of hollow silica spheres: S21, adding the obtained induced carbon spheres to a mixed solution of water and ethanol, uniformly dispersing them by ultrasonication, then adding ammonia water, and continuing ultrasonication to obtain solution B; S22, prepare tetraethyl silicate / ethanol solution, add solution B dropwise to the tetraethyl silicate / ethanol solution, and stir to react; S23. After the reaction is completed, the mixture is centrifuged and dried, placed under closed conditions, heated, and calcined to obtain hollow silica spheres with self-recessed micro-nano structures.

2. The method for preparing the self-recessed micro-nanostructured hollow silica spheres according to claim 1, wherein: In step S11, the volume ratio of acetonitrile, ethanol and ammonia water is 35-50:80-170:1-5.

3. The method for preparing the self-recessed micro-nanostructured hollow silica spheres according to claim 1, wherein: In step S11, the stirring reaction time is 6-12 hours.

4. The method for preparing self-recessed micro-nanostructured hollow silica spheres according to claim 1, wherein: In step S21, the mass volume ratio of the induced carbon spheres, water, ethanol and ammonia water is 3-20 mg: 20-30 mL: 100-120 mL: 1-3 mL.

5. The method for preparing self-recessed micro-nanostructured hollow silica spheres according to claim 1, wherein: In step S22, the volume ratio of the tetraethyl silicate / ethanol solution to solution A is 26-37:20-35.

6. The method for preparing self-recessed micro-nanostructured hollow silica spheres according to claim 1, wherein: In the tetraethyl silicate / ethanol solution, the mass ratio of tetraethyl silicate to ethanol is 8:18-29.

7. The method for preparing self-recessed micro-nanostructured hollow silica spheres according to claim 1, wherein: In step S22, the dropwise addition rate is 1-2 mL / h; and the stirring reaction time is 10-18 h.

8. The method for preparing self-recessed micro-nanostructured hollow silica spheres according to claim 1, characterized in that: In step S23, the heating rate is 5-8°C / min, the calcination temperature is 400-600°C, and the calcination time is 2-6h.

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