A method for preparing a polymer precursor derived all-inorganic superhydrophobic coating

Abstract

The application belongs to the technical field of material surface functionalization protection, and particularly discloses a preparation method of a polymer precursor derived all-inorganic super-hydrophobic coating, which comprises the following steps: preparing metal, glass and ceramic with micro-nano surface structure by micro-arc oxidation and hydrothermal method; adding polysilane precursor, ethyl silicate and dibutyltin dilaurate complex catalyst into n-hexane or n-heptane to configure a precursor solution; and immersing the material with micro-nano surface structure into the solution; and placing the material coated with the precursor into a high-temperature furnace to obtain the all-inorganic super-hydrophobic coating under a non-oxygen environment. The preparation method of the polymer precursor derived all-inorganic super-hydrophobic coating is safe, environmentally friendly, practical, simple to operate, and strong in designability, and can realize the all-inorganic super-hydrophobic coating on the surface of metal, glass and ceramic materials, and has excellent high-temperature resistance, wear resistance, corrosion resistance, waterproofness and self-cleaning performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material surface functionalization protection, and particularly relates to a preparation method of a polymer precursor derived all-inorganic super-hydrophobic coating. BACKGROUND

[0002] There are many super-hydrophobic surfaces in nature, such as lotus leaves, butterfly wings, rice leaves, etc. The biomimetic super-hydrophobic surface has attracted extensive attention due to its potential application prospects such as self-cleaning, waterproof, anti-icing, anti-fogging, etc. Generally, these super-hydrophobic materials are modified with a low-surface-energy organic coating, such as organosilicon, fluorosilicon resin, etc. on a rough surface with micro-nano structure. However, the prepared super-hydrophobic surface has poor durability, high-temperature stability and environmental adaptability. On the other hand, regarding the inorganic super-hydrophobic coating: the related reports about the preparation of super-hydrophobic coating by organic-inorganic hybridization use organic binders as low-surface-energy materials, which also have poor temperature resistance. The patent No. CN114836725A discloses a preparation method of a low-temperature steel inorganic super-hydrophobic anti-icing coating structure, which mainly uses rare earth oxides to form a prism array to construct a hydrophobic structure. Therefore, in order to solve the problems of poor wear resistance, poor temperature resistance and poor weather resistance of traditional super-hydrophobic materials, a polymer-derived all-inorganic super-hydrophobic coating with high-temperature resistance, wear resistance and corrosion resistance is prepared, which can greatly improve the wear resistance, temperature resistance and weather resistance of the coating and has excellent properties such as waterproofness and self-cleaning, and has broad prospects in practical engineering applications. SUMMARY

[0003] The purpose of the present application is to provide a preparation method of a polymer precursor derived all-inorganic super-hydrophobic coating, which is safe, environmentally friendly, practical, simple to operate and strong in designability, and realizes all-inorganic super-hydrophobic coating on the surface of metal, glass and ceramic materials. The contact angle of the coating can reach more than 168°, the sliding angle is less than 5°, and the coating has excellent high-temperature resistance, wear resistance, corrosion resistance, waterproofness and self-cleaning performance. The method provides a new idea for realizing the protection of base materials and large-scale application.

[0004] To achieve the above-mentioned purpose, the present application provides a preparation method of a polymer precursor derived all-inorganic super-hydrophobic coating, which comprises the following steps:

[0005] Step one, preparing metal, glass and ceramic materials with micro-nano surface structure, the metal being one of aluminum, magnesium and titanium;

[0006] Step two, adding polysilane precursor, ethyl silicate and dibutyltin dilaurate complex catalyst into n-hexane or n-heptane to configure a precursor solution, stirring, and immersing the material with micro-nano surface structure prepared in step one into the solution for 10-60 min;

[0007] Step three, put the coated precursor material obtained in step two into a high-temperature furnace, and the polysilane precursor is coordinated with ethyl silicate to form a stable macromolecular network structure, and a new type of Si-C-O-H hydrophobic group is formed and maintained in a non-oxygen environment, and the inorganic super-hydrophobic coating is obtained by heating.

[0008] Preferably, in step one, a micro-arc oxidation method is used to prepare a metal surface with a multi-scale porous and cauliflower-like micro-nano structure, and a hydrothermal, alkali thermal or high-pressure hydrothermal method is used to prepare a glass or ceramic surface with a multi-scale cauliflower-like or needle-like micro-nano structure.

[0009] Preferably, the micro-arc oxidation is carried out by placing the metal in an alkaline electrolyte, setting the temperature to 30-50℃, applying a voltage of 500-600V, a frequency of 200-1000Hz and a duty cycle of 4-30%, and then treating the metal surface by micro-arc oxidation to obtain a ceramic coating with a porous structure on the metal surface.

[0010] Preferably, the ceramic coating with a porous structure on the metal surface is treated by a hydrothermal, alkali thermal or high-pressure hydrothermal method to grow a multi-scale cauliflower-like or needle-like micro-nano structure on the surface in situ, thereby providing roughness and a double-scale structure for the super-hydrophobic coating.

[0011] Preferably, in step two, the precursor solution is prepared by adding 10-50g of polysilane precursor, 2-7g of ethyl silicate and 1-5g of dibutyltin dilaurate complex catalyst into 20-60g of n-hexane or n-heptane, and stirring for 20-60min.

[0012] Preferably, in step three, the high-temperature furnace is heated to a temperature of 400-500℃ for 1-4 hours.

[0013] Preferably, in step three, the non-oxygen environment in the high-temperature furnace includes nitrogen, argon or vacuum.

[0014] Preferably, in step three, the inorganic super-hydrophobic composite coating has a thickness of 20-200μm, a contact angle of 168° or more, and a sliding angle of less than 5°, and can withstand a high temperature of 400-500℃ while still maintaining super-hydrophobicity at a high temperature of 400-500℃.

[0015] The advantages and beneficial effects of the above-mentioned method for preparing a polymer precursor-derived inorganic super-hydrophobic coating are:

[0016] 1. The method uses organic precursor polymer-derived cracking to prepare an inorganic super-hydrophobic coating with a multi-scale micro-nano structure on the surface of metal, glass and ceramic materials. This method is fast, convenient, efficient, can be used to prepare large-area special-shaped components, and has a large design space.

[0017] 2. The application provides a high-temperature-resistant, wear-resistant and corrosion-resistant all-inorganic super-hydrophobic coating layer formed by polymer derivation, wherein the coating layer is dense, the surface quality is high, and the thickness is controllable in the range of 20-200 microns.

[0018] 3. The application forms the high-temperature-resistant, wear-resistant and corrosion-resistant all-inorganic super-hydrophobic coating layer by polymer derivation, and has excellent mechanical chemical stability, greatly improved wear resistance, improved corrosion resistance by more than 3 orders of magnitude, greatly improved high-temperature resistance compared with organic coating, and excellent environmental adaptability, waterproofness and self-cleaning performance.

[0019] 4. The application forms the high-temperature-resistant, wear-resistant and corrosion-resistant all-inorganic super-hydrophobic coating layer by polymer derivation, wherein the coating layer has a multi-layer structure, the outermost layer forms a Si-C-O all-inorganic super-hydrophobic layer with low surface energy methyl, the contact angle is more than 168 degrees, the sliding angle is less than 5 degrees, the coating layer has excellent mechanical chemical robustness and waterproofness and self-cleaning performance, and provides a new method for realizing protection and large-scale application of metal, glass, ceramic and other substrate materials.

[0020] The technical scheme of the application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structure schematic diagram of the all-inorganic super-hydrophobic coating layer formed by polymer precursor derivation of the application;

[0022] Figure 2 It is a structure schematic diagram of the high-stable low-surface-energy macromolecular network formed by polysilane precursor reaction polymerization of the application;

[0023] Figure 3 It is a surface micro-morphology diagram of the micro-arc oxidation coating layer of the titanium alloy in Example 1 of the application;

[0024] Figure 4 It is a surface micro-morphology diagram of the micro-arc oxidation hydrothermal composite coating layer of the titanium alloy in Example 1 of the application;

[0025] Figure 5 It is a surface micro-morphology diagram of the all-inorganic super-hydrophobic coating layer formed by polymer derivation on the surface of the micro-arc oxidation hydrothermal composite coating layer of the titanium alloy in Example 1 of the application;

[0026] Figure 6 It is a static contact angle schematic diagram of the all-inorganic super-hydrophobic coating layer formed by polymer derivation on the surface of the micro-arc oxidation hydrothermal composite coating layer of the titanium alloy in Example 1 of the application;

[0027] Figure 7 It is a rolling angle schematic diagram of the all-inorganic super-hydrophobic coating layer formed by polymer derivation on the surface of the micro-arc oxidation hydrothermal composite coating layer of the titanium alloy in Example 1 of the application;

[0028] Figure 8 Polarization curve diagram of the all-inorganic super-hydrophobic coating derived from the surface of the micro-arc oxidation and hydrothermal composite coating of the titanium alloy of Example 1 of the present application;

[0029] Figure 9 Schematic diagram of the abrasion resistance test of the all-inorganic super-hydrophobic coating derived from the surface of the micro-arc oxidation and hydrothermal composite coating of the titanium alloy of Example 1 of the present application;

[0030] Figure 10 Diagram of the contact angle change after abrasion of the all-inorganic super-hydrophobic coating derived from the surface of the micro-arc oxidation and hydrothermal composite coating of the titanium alloy of Example 1 of the present application;

[0031] Figure 11 High-temperature stability curve diagram of the all-inorganic super-hydrophobic coating derived from the surface of the micro-arc oxidation and hydrothermal composite coating of the titanium alloy of Example 1 of the present application;

[0032] Figure 12 Microscopic morphology diagram of the all-inorganic super-hydrophobic coating of Example 3 of the present application, wherein (a) is the micro-nano structure of the Al2O3 ceramic surface, and (b) is the cauliflower-like micro-nano structure of the SiO2 ceramic surface;

[0033] Figure 13 Columnar diagram of the contact angle of the all-inorganic super-hydrophobic coating of Example 3 of the present application;

[0034] Figure 14 High-temperature resistance performance diagram of the all-inorganic super-hydrophobic coating of Example 3 of the present application. DETAILED DESCRIPTION

[0035] The technical solutions of the present application are further described below through the accompanying drawings and examples.

[0036] Unless otherwise defined, the technical terms or scientific terms used in the present application shall have the usual meanings understood by those with ordinary skills in the art to which the present application belongs.

[0037] Unless otherwise defined, the reagents and equipment used in the present application are commercially available.

[0038] Example 1

[0039] A preparation method of a polymer precursor-derived all-inorganic super-hydrophobic coating, comprising the following steps:

[0040] I. TA15 titanium alloy was selected as the substrate, and the surface was polished with 600, 800 and 1000# sandpaper in sequence, and then ultrasonically cleaned with anhydrous ethanol and deionized water for 10 min, respectively.

[0041] 2. Prepare a basic electrolyte by mechanically stirring 12 g / L sodium silicate, 8 g / L sodium hexametaphosphate, and 2 g / L sodium hydroxide.

[0042] 3. Use a stainless steel plate or stainless steel cell as the cathode and TA15 titanium alloy as the anode. Use the above-mentioned basic electrolyte and apply a pulse voltage of 600V between the cathode and cathode electrodes. The current density is 28000A / m 2 ; Time: 15 min, frequency: 500 Hz, duty cycle: 25%, solution temperature controlled at 30°C, and under continuous stirring conditions, a micro-arc oxidation ceramic coating was prepared with a coating thickness of 30 μm.

[0043] 4. The prepared micro-arc oxidation coating was subjected to hydrothermal treatment. The method is as follows: 0.1g of sodium hydroxide (NaOH), 4g of aluminum nitrate (Al(NO3)3·9H2O), and 0.2g of calcium acetate (Ca(CH3COO)2) were dissolved in 30mL of deionized water, and 0.3g of hexamethylenetetramine (C6H 12 N4) to prepare a solution. The solution was poured into a Teflon-lined stainless steel autoclave and stirred with a magnetic stirrer for 20 minutes. The micro-arc oxidation coating was then placed into the mixed solution and subjected to a hydrothermal reaction at 150°C for 18 hours to prepare a micro-arc oxidation hydrothermal composite layer.

[0044] 5. Add 10g of polysilane precursor, 2g of tetraethyl orthosilicate (TEOS), and 1g of dibutyltin dilaurate (DBTDL) catalyst to 20g of n-hexane to prepare a solution, which is stirred for 30 minutes. Immerse the prepared micro-arc oxidation hydrothermal composite coating in the solution and maintain it at room temperature for 40 minutes.

[0045] 6. The composite coating was taken out of the solution, placed in a tube furnace, heated to 400°C in an atmosphere of 99.9% nitrogen, and kept warm for 3 hours to obtain a 60 μm thick all-inorganic superhydrophobic coating with excellent high temperature resistance, wear resistance, and corrosion resistance.

[0046] The all-inorganic superhydrophobic coating prepared by the method of this embodiment has excellent superhydrophobic properties, a static contact angle greater than 168°, a rolling angle less than 5°, excellent mechanochemical robustness, and waterproof and self-cleaning properties, providing a new method for achieving protection and large-scale application of metal, inorganic and other substrate materials.

[0047] Figure 1 Schematic diagram of the structure of the all-inorganic super-hydrophobic coating derived from the polymer precursor of the present invention. Figure 1As shown, the preparation method can prepare a ceramic coating on the surface of a metal substrate, form a micro-nano structure after hydrothermal treatment, and form a fully inorganic superhydrophobic coating after coating with an inorganic superhydrophobic coating derived from a modified polymer precursor; or directly perform hydrothermal treatment or autoclave treatment on the ceramic surface to perform micro-nanostructural treatment to form a multi-scale structure, and form a fully inorganic superhydrophobic coating after modification by a polymer precursor.

[0048] Figure 2 The schematic diagram of the polysilane precursor reaction polymerization to form a highly stable low surface energy macromolecular network structure. Figure 2 As shown, under the action of ethyl silicate and a catalyst, linear polysilane forms a closed-loop polymerization state, and the molecular chains are entangled. The polymer chain grows to form new active points. The multi-active point cross-linking polymerization forms a highly stable macromolecular network structure, which can form a coordination structure that protects hydrophobic groups at high temperatures, thereby maintaining long-term high-temperature stable service. In addition, by coordinating the polysilane precursor with ethyl silicate and treating it in a vacuum or non-oxygen atmosphere, the polymer polymerization can be promoted to form alkyl groups in the macromolecular chain. Such alkyl groups can remain hydrophobic at high temperatures. This is attributed to the formation of Si-COH through cyclic polymerization. This complex functional group repels water molecules, producing a shielding effect, making it difficult to adsorb water molecules at the interface and thus showing hydrophobicity.

[0049] like Figure 3 As shown in FIG, a titanium oxide (TiO2)-based ceramic coating with a porous structure is prepared on the surface of a titanium alloy using micro-arc oxidation technology, providing a ceramic template for the subsequent formation of micro-nanostructures.

[0050] like Figure 4 As shown, a hydrothermal method is used to in situ grow special structures with micro-nano needles (aspect ratio 20:1), cauliflower-like (diameter 1-3μm), and square shapes on the surface of the titanium oxide (TiO2)-based ceramic coating, providing roughness and micro-nano multi-scale structure for the hydrophobic / super-hydrophobic surface.

[0051] like Figure 5 As shown, a polymer precursor is coated on the surface of the micro-nano structure, and further high-temperature derivatization transformation is performed to form a high-temperature resistant, wear-resistant, and corrosion-resistant all-inorganic superhydrophobic coating. The coating surface presents a multi-scale micro-nano superhydrophobic structure, with needle-shaped and cauliflower-shaped surfaces providing a hierarchical structure, and the polymer precursor transformation product provides low surface energy.

[0052] like Figure 6 As shown in the figure, the surface contact angle of the all-inorganic super-hydrophobic coating was tested to be 168.9°, which has excellent water resistance.

[0053] like Figure 7 As shown in the figure, the surface rolling angle test of the all-inorganic super-hydrophobic coating is 5°, which has excellent water resistance.

[0054] like Figure 8 As shown in the figure, the corrosion potential and corrosion current density in the polarization curve are key parameters for evaluating the corrosion resistance of the coating. The results show that compared with the substrate and single micro-arc oxidation, the all-inorganic super-hydrophobic coating has the smallest corrosion current and the highest corrosion potential, showing the best corrosion resistance. This is attributed to the fact that on the one hand, the super-hydrophobic coating hinders the direct contact between the corrosive medium and the substrate, slowing down its corrosion rate; on the other hand, the all-inorganic super-hydrophobic outer layer forms a strong sealing effect on the porous micro-arc oxidation layer, preventing the corrosive medium from penetrating the coating to corrode the substrate, and the improvement of its overall density significantly enhances the corrosion resistance of the coating, which is conducive to long-term corrosion protection.

[0055] like Figure 9 and Figure 10 As shown in the figure, the all-inorganic super-hydrophobic coating was subjected to a friction and wear test using 240 sandpaper, a load of 100g, and a distance of 5cm from the center of the rotating platform to the center of the sample. The results showed that after 80 friction and wear cycles, the contact angle of the coating surface was still greater than 154°, indicating that the coating has excellent wear resistance and robustness.

[0056] like Figure 11 As shown in the figure, the all-inorganic super-hydrophobic coating was placed in a high temperature environment (500℃ for 2h and 400℃ for 48h). It was found that after being treated at 500℃ for 2h, the all-inorganic super-hydrophobic coating still maintained super-hydrophobicity (contact angle>150.2°), and water droplets could roll freely on the surface of the coating. Under extreme high temperature conditions, the all-inorganic precursor conversion and micro-nano rough structure can give the coating super-hydrophobicity. After 48h at 400℃, the coating still has super-hydrophobicity, and the contact angle is still>151°. Such a special all-inorganic precursor conversion combined with micro-nano structure gives the coating long-term high-temperature super-hydrophobic properties.

[0057] Example 2

[0058] A method for preparing a polymer precursor-derived all-inorganic super-hydrophobic coating comprises the following steps:

[0059] 1. Select AZ31 magnesium alloy as the substrate, polish the surface with 800, 1000 and 1200# sandpaper in sequence, and then ultrasonically clean it with anhydrous ethanol and deionized water for 20 minutes respectively;

[0060] 2. Mechanically stir 12 g / L sodium silicate, 8 g / L sodium hexametaphosphate, and 2 g / L sodium hydroxide to prepare a basic electrolyte;

[0061] 3. Use a stainless steel plate or stainless steel cell as the cathode and AZ31 magnesium alloy as the anode. Use the above basic electrolyte to apply a 400V pulse voltage between the cathode and anode electrodes. The current density is 12000A / m 2; Time: 20min, frequency: 800Hz, duty cycle: 30%, solution temperature is controlled at 30℃, and under continuous stirring conditions, the solution temperature is controlled at 30℃, and under continuous stirring conditions, a micro-arc oxidation ceramic coating is prepared with a coating thickness of 38μm.

[0062] 4. The prepared micro-arc oxidation coating was subjected to hydrothermal treatment. The method is as follows: 0.2g NaOH, 5g Al(NO3)3·9H2O, and 0.5g Ca(CH3COO)2 were dissolved in 30mL deionized water, and 0.5g C6H 12 N4, prepare a solution. Pour the solution into a Teflon-lined stainless steel autoclave and stir with a magnetic stirrer for 30 minutes. Then, place the micro-arc oxidation coating into the mixed solution and perform a hydrothermal reaction at 180°C for 24 hours to prepare a micro-arc oxidation hydrothermal composite coating.

[0063] 5. Add 20g of polysilane precursor, 3g of TEOS, and 2g of DBTDL catalyst to 38g of n-heptane to prepare a solution and stir for 20 minutes. Immerse the prepared micro-arc oxidation hydrothermal composite coating in the solution and immerse it at room temperature for 30 minutes.

[0064] 6. The composite coating was taken out of the solution, placed in a tube furnace, heated to 450°C in a non-oxygen atmosphere (argon), and kept warm for 4 hours to obtain a 50 μm thick all-inorganic superhydrophobic coating with excellent high temperature resistance, wear resistance, and corrosion resistance.

[0065] The all-inorganic super-hydrophobic coating prepared by the method of this embodiment has excellent super-hydrophobic properties, a static contact angle of 169°, a rolling angle of 4°, and excellent high temperature resistance, wear resistance, corrosion resistance, waterproofness and self-cleaning properties, providing a new method for achieving the protection and large-scale application of metal, inorganic and other substrate materials.

[0066] Example 3

[0067] A method for preparing a polymer precursor-derived all-inorganic super-hydrophobic coating comprises the following steps:

[0068] 1. Select alumina (Al2O3) ceramics and silicon dioxide (SiO2) glass respectively;

[0069] Second, Al2O3 ceramics and SiO2 glass were subjected to autoclave hydrothermal treatment. The method is as follows: 0.5g NaOH, 7g Al(NO3)3·9H2O, 1.0g Ca(CH3COO)2 were dissolved in 40mL deionized water, and 0.8g C6H 12N4, to prepare a solution. The solution was poured into a Teflon-lined stainless steel autoclave, Al2O3 ceramics and SiO2 glass were placed in the mixed solution, and a high-pressure hydrothermal reaction was carried out at a temperature of 220°C and 50MPa. After a reaction time of 36 hours, multi-scale micro-nano structures (such as Figure 12 shown).

[0070] Third, 40g of polysilane precursor, 6.5g of TEOS, and 4g of DBTDL catalyst were added to 60g of n-heptane to prepare a solution, which was stirred for 30 minutes. Micro-nanostructured Al2O3 ceramics and SiO2 glass were placed in the solution and kept at room temperature for 40 minutes to prepare a composite coating on their surfaces.

[0071] 4. The composite coating was taken out of the solution, placed in a tubular furnace, heated to 450°C in a non-oxygen atmosphere (N2), and kept warm for 2 hours to obtain a 70 μm thick all-inorganic superhydrophobic coating with excellent high temperature resistance, wear resistance, and corrosion resistance.

[0072] The all-inorganic super-hydrophobic coating prepared by the method of this embodiment has excellent super-hydrophobic properties. Figure 13 As shown in Figure 2, the static contact angle of the coating is >169°. Figure 14 As shown, the coating exhibits excellent high-temperature resistance of 500°C, which provides ideas for the application of superhydrophobic coatings in high-temperature environments. At the same time, the composite coating has good waterproof and self-cleaning properties, providing a new method for achieving protection and large-scale application of inorganic matrix materials.

[0073] At present, super-hydrophobic coatings are mainly based on organic coatings, and mainly utilize hydrocarbon groups and ester groups: hydrocarbon groups such as C10~C20; hydrocarbon groups containing groups such as aromatic groups, esters, ethers, amines, amides; polyoxypropylene groups, long-chain perfluoroalkyl groups, etc. These materials all have low surface energy, but at high temperatures, whether it is CH or CF, pyrolysis occurs, and even volatilization causes hydrophobic group destruction, which is difficult to apply at high temperatures. A novel hydrophobic group Si-COH proposed in the present invention, due to the formation of a high-stability macromolecular network structure, can form a coordination structure protecting the hydrophobic group at high temperatures, ensuring long-term high-temperature service. On the other hand, the coating is coordinated with ethyl silicate by a polysilane precursor, and the alkyl group that promotes polymer polymerization to form a macromolecular chain is processed in a vacuum or non-oxygen atmosphere, not only ensuring the high-temperature service stability of the coating, but also still maintaining hydrophobicity or even super-hydrophobicity at high temperatures, which is of great significance for super-hydrophobic coatings to serve for a long time at high temperatures. In addition, the coating can be made into a coating or adhesive through molecular-scale design and widely used on the surfaces of different materials. The preparation method is simple and practical. In the future, it is expected to be widely used in high-temperature components, especially aircraft surfaces, for waterproofing and anti-icing.

[0074] Therefore, the present invention adopts the above-mentioned method for preparing a polymer precursor-derived all-inorganic super-hydrophobic coating, which is safe, environmentally friendly, practical, simple to operate, and highly designable. It can realize an all-inorganic super-hydrophobic coating on the surface of metal, glass, and ceramic materials. The contact angle of the coating can reach more than 168°, and the sliding angle is less than 5°. It has excellent high temperature resistance, wear resistance, corrosion resistance, waterproofness and self-cleaning properties. This method provides a new idea for realizing substrate material protection and large-scale application.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a polymer precursor-derived all-inorganic super-hydrophobic coating, characterized in that: The steps include: Step 1: preparing a metal with a micro-nano surface structure, wherein the metal is one of aluminum, magnesium, titanium and alloys thereof; Step 2: Add polysilane precursor, ethyl silicate and dibutyltin dilaurate complex catalyst into n-hexane or n-heptane to prepare a precursor solution, stir, and immerse the material with micro-nano surface structure prepared in step 1 into the solution for 10-60 minutes; Step 3: Place the precursor-coated material obtained in step 2 into a high-temperature furnace, where the polysilane precursor coordinates with ethyl silicate to form a stable macromolecular network structure. In a non-oxygen environment, Si-COH hydrophobic groups are formed and maintained, and heating is performed to obtain a fully inorganic super-hydrophobic coating. In step 1, a multi-scale porous and cauliflower-like micro-nanostructure is prepared on the metal surface by micro-arc oxidation; Micro-arc oxidation is to place the metal in an alkaline electrolyte, set the temperature to 30℃~50℃, apply a voltage of 500V~600V, a frequency of 200Hz~1000Hz and a duty cycle of 4%~30%, and perform micro-arc oxidation treatment on the metal surface to obtain a ceramic coating with a porous structure on the metal surface; The ceramic coating with a porous structure on the metal surface is treated by hydrothermal and alkaline thermal methods to in situ grow multi-scale cauliflower-like or needle-like micro-nanostructures on the surface, providing roughness and dual-scale structure for the super-hydrophobic coating. In step 2, a precursor solution is prepared by adding 10-50 g of polysilane precursor, 2-7 g of ethyl silicate and 1-5 g of dibutyltin dilaurate complex catalyst into 20-60 g of n-hexane or n-heptane, respectively, and stirring for 20-60 minutes.

2. The method for preparing a polymer precursor-derived all-inorganic super-hydrophobic coating according to claim 1, wherein: In step 3, the high temperature furnace is heated to 400-500° C. for 1-4 hours.

3. The method for preparing a polymer precursor-derived all-inorganic super-hydrophobic coating according to claim 1, wherein: In step 3, the non-oxygen environment in the high-temperature furnace includes nitrogen, argon, and vacuum.

4. The method for preparing a polymer precursor-derived all-inorganic super-hydrophobic coating according to claim 1, wherein: In step three, the thickness of the all-inorganic super-hydrophobic composite coating is 20 μm-200 μm, the contact angle is ≥168°, the sliding angle is <5°, and it is resistant to high temperatures of 400-500°C.

Images