Conductive self-healing ag / pdms coating for lunar dust protection and preparation method and application thereof

Abstract

The application discloses a conductive self-repairing Ag / PDMS coating for lunar dust protection and a preparation method and application thereof, and belongs to the technical field of space special functional materials. Epoxy resin A is dissolved in ethyl acetate, multi-walled carbon nanotubes, modified nano-silicon dioxide particles, a silane coupling agent, epoxy resin B and polydimethylsiloxane and a curing agent thereof are sequentially added into the ethyl acetate, and are uniformly mixed, sprayed and obtained, so that the conductive self-repairing Ag / PDMS coating with dustproof performance is obtained. The coating has the characteristics of low cost, no need of additional energy and maintenance, integration of dustproof, conductive and self-repairing functions, and can realize long-term dustproof ability on the lunar surface, can significantly reduce the adhesion of lunar dust on the surface of a spacecraft and a spacesuit, and has a wide application prospect in future manned lunar landing and deep space exploration activities.

Description

Technical Field

[0001] This invention belongs to the field of space special functional materials technology, specifically relating to conductive self-healing Ag / PDMS coatings for lunar dust protection, their preparation methods and applications. Background Technology

[0002] Humanity's deep-space lunar exploration program faces numerous harsh space environment challenges. The lunar surface lacks an atmosphere for protection and is subjected to continuous erosion by the solar wind and frequent impacts from micrometeorites, resulting in a loose lunar regolith layer with an average particle size of 40-130 μm. The ultrafine lunar dust particles contained within are easily stirred up by natural levitation or the impact of probe engine plumes. These tiny lunar dust particles adhere easily to the surfaces of spacecraft and spacesuits due to van der Waals forces and electrostatic forces, making them difficult to remove. This can also cause safety hazards such as spacecraft seal failure, reduced heat dissipation performance, and malfunctions of precision equipment, seriously threatening the operational stability of lunar exploration equipment. Therefore, conducting research on efficient and long-term lunar dust protection technologies is of significant engineering value and research importance for ensuring the smooth progress of lunar exploration missions.

[0003] Currently, mainstream lunar dust protection technologies are divided into two main categories: active protection technologies and passive protection technologies. Active protection technologies rely on external energy input or physical force to remove lunar dust, including electrostatic dust removal, magnetic dust removal, mechanical brush cleaning, and fluid purging. Passive protection technologies do not require additional energy supply or complex external equipment. They regulate the interfacial adhesion performance through physical and chemical modification of the substrate surface and rely on the intrinsic properties of the coating itself to inhibit lunar dust adhesion. They have the advantages of low cost, maintenance-free operation, and adaptability to the extreme vacuum space environment, and have now become a research hotspot in the field of lunar dust protection.

[0004] Considering the adhesion mechanism of lunar dust, the influence of capillary forces is negligible in the vacuum environment of the moon. The adhesion between lunar dust and the substrate surface mainly originates from van der Waals forces and electrostatic forces. Existing passive dustproof coatings still have significant limitations in application. The extreme space environment of the moon will continuously cause chemical damage to the coating, destroying the low surface energy components of the coating surface and thus weakening its dustproof performance. At the same time, sharp and hard lunar dust will also wear down the microstructure of the coating, shortening its service life. Conventional dustproof coatings without self-healing capabilities cannot autonomously repair interface damage and are difficult to adapt to the complex working conditions of the moon for a long time. Therefore, there is an urgent need for superhydrophobic dustproof coatings with chemical self-healing capabilities. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a conductive self-healing Ag / PDMS coating for lunar dust protection, its preparation method and application, so as to solve the technical problem that existing lunar dust protection coatings cannot autonomously compensate for interface damage.

[0006] To achieve the above objectives, the present invention employs the following technical solution: The first aspect of the present invention discloses a method for preparing a conductive self-healing Ag / PDMS coating with dustproof properties, characterized in that epoxy resin A is dissolved in ethyl acetate, and multi-walled carbon nanotubes, modified nano-silica particles, silane coupling agent, epoxy resin B and polydimethylsiloxane and its curing agent are added sequentially thereto, mixed evenly, and sprayed to obtain a conductive self-healing Ag / PDMS coating with dustproof properties.

[0007] Preferably, the modified nano-silica particles are prepared by dispersing nano-silica particles in anhydrous ethanol, adding a silane modifier, mixing, washing, and drying to obtain modified nano-silica particles.

[0008] More preferably, the silane modifier is octadecyltrichlorosilane or fluorosilane.

[0009] Preferably, the mixing is achieved by magnetic stirring at 55~65℃ and a rotation speed of 400~1000 r / min for 2~4 h.

[0010] Preferably, the ratio of nano-silica particles to anhydrous ethanol is 1 g: (8~20) mL, and the ratio of nano-silica particles to silane modifier is (2.5~4) g: 1 mL.

[0011] Preferably, silver powder is added before adding the silane coupling agent.

[0012] Preferably, the ratio of epoxy resin A to ethyl acetate is 1 g: (6~12) mL; the mass ratio of multi-walled carbon nanotubes to modified nano-silica particles is 1: (10~50); the ratio of silane coupling agent to modified nano-silica is 1 mL: (1~6) g; the mass ratio of epoxy resin B to epoxy resin A is 1: (2~5); and the ratio of polydimethylsiloxane to epoxy resin A is 1 mL: 2 g.

[0013] Preferably, the silane coupling agent is 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, or bisaminosilane.

[0014] Preferably, after spraying, the sample formed by spraying is heated and cured.

[0015] In a second aspect, the present invention discloses a conductive self-healing Ag / PDMS coating with dustproof properties prepared by the above-described preparation method.

[0016] A third aspect of the present invention discloses the application of the above-mentioned dustproof conductive self-healing Ag / PDMS coating in the preparation of lunar exploration space equipment, detectors, rovers or spacesuits.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for preparing a conductive self-healing Ag / PDMS coating for lunar dust protection. 1) Introducing multi-walled carbon nanotubes (MWCNTs) into the coating system helps to uniformly construct a continuous and stable two-dimensional conductive network inside the coating, giving the coating electrostatic dissipation capability; 2) Using a composite system of polydimethylsiloxane (PDMS) and modified SiO2 (with hydrophobic properties) particles, the two form a highly efficient synergistic effect; PDMS provides the coating with extremely low surface energy, and modified nano-silica particles can construct a uniform micro-rough structure on the coating surface. The combination of the two perfectly matches the superhydrophobic and dustproof structural mechanism, significantly reducing the adhesion force on the coating surface; 3) The silane coupling agent added to the coating system can effectively improve the interfacial compatibility between different components such as epoxy resin, carbon nanotubes, modified silica, and PDMS inside the coating, solving the problems of delamination, agglomeration, and loose bonding that easily occur in multi-component composite systems, and significantly improving the overall bonding strength inside the coating. Meanwhile, silane coupling agents can achieve efficient bonding between the coating and the substrate, significantly enhancing the adhesion performance of the coating to commonly used aerospace substrates, avoiding peeling and flaking problems in extreme environments such as alternating high and low temperatures, vacuum, and micro-meteorite impacts on the moon, and ensuring the integrity of the coating during long-term service; 4) The epoxy resin (A glue and B glue) added to the coating system can form a high-strength cross-linked network after curing. Combined with the particle reinforcement effect of modified nano-silica, the two form a synergistic reinforcement effect, effectively improving the coating's hardness, wear resistance, tensile strength and other comprehensive mechanical properties, allowing the coating to resist external damage such as wind and sand abrasion, micro-friction, and slight impacts on the lunar surface, and greatly adapting to the harsh service environment of deep space exploration. Experiments have shown that the coating prepared by this method achieves a surface roughness of 5.1–6.8 μm, exhibiting excellent dustproof performance significantly superior to materials such as aluminum sheets and PMMA acrylic sheets. The adhesion force is as low as 24.88 nN, and the sheet resistance ranges from 0.25 to 21.24 kΩ / sq, demonstrating stable semiconductor conductivity. It exhibits ≥6 ultimate self-healing cycles, and after 40 wear cycles, the water contact angle remains around 140°. Therefore, this coating is characterized by low cost (it is a passive protective coating, requiring no energy supply), no need for additional energy or maintenance, and integrates dustproof, conductive, and self-healing functions. It can achieve long-term dustproof capability on the lunar surface, significantly reducing lunar dust adhesion to spacecraft and spacesuits, and has broad application prospects in future manned lunar landings and other deep space exploration activities.

[0018] Furthermore, modifying silica with octadecyltrichlorosilane can reduce the surface energy of silica, giving silica particles hydrophobic properties.

[0019] Furthermore, Ag powder can form a dual conductive network with multi-walled carbon nanotubes, further enhancing the conductivity of the coating; PDMS and modified SiO2 together achieve superhydrophobicity of the coating surface, while PDMS enables the coating to have chemical self-healing capabilities. Attached Figure Description

[0020] Figure 1 These are electron microscope (SEM) images of the surface morphology of the dustproof conductive self-healing Ag / PDMS coating of the present invention; wherein, (a) is Example 3, a2 is an enlarged view of the boxed position in a1, a3 is an enlarged view of the boxed position in a2, a4 is an enlarged view of the boxed position in a3, a5 is an enlarged view of the boxed position in a4, a6 is an enlarged view of the boxed position in a5, (b) is Example 5; b2 is an enlarged view of the boxed position in b1, b3 is an enlarged view of the boxed position in b2, b4 is an enlarged view of the boxed position in b3, b5 is an enlarged view of the boxed position in b4, b6 is an enlarged view of the boxed position in b5; Figure 2 This is a graph showing the water contact angle measurement results of the dustproof, conductive, self-healing Ag / PDMS coating of the present invention; Figure 3 The graph shows the test results of the conductivity of the dustproof, conductive, self-healing Ag / PDMS coating of the present invention. Figure 4 The figures show the self-healing test results of the dustproof, conductive, and self-healing Ag / PDMS coating of the present invention; where (a) is Example 2, (b) is Example 3, (c) is Example 4, and (d) is Example 5. Figure 5 The image shows the dustproof test results of the Ag / PDMS coating with dustproof, conductive, and self-healing properties according to the present invention. Detailed Implementation

[0021] To enable those skilled in the art to understand the features and effects of the present invention, the following description and definitions are only general descriptions of the terms and expressions mentioned in the specification. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0022] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0023] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0024] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0025] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0026] This invention provides a method for preparing a conductive self-healing Ag / PDMS coating with dustproof properties, comprising the following steps: 1. Disperse nano-silica particles in anhydrous ethanol, add silane modifier, and magnetically stir for 2-4 h in a water bath at 55-65℃ and a speed of 400-1000 r / min. Wash and dry several times with anhydrous ethanol to obtain modified nano-silica particles. The ratio of nano-silica particles to anhydrous ethanol is 1 g: (8~20) mL, and the ratio of nano-silica particles to silane modifier is (2.5~4) g: 1 mL; the silane modifier includes, but is not limited to, octadecyltrichlorosilane or fluorosilane. 2. Dissolve epoxy resin A in ethyl acetate, add multi-walled carbon nanotubes and modified nano-silica particles obtained in step 1, and ultrasonically disperse for 5-20 min. Then add silver powder and silane coupling agent, and ultrasonically disperse for 20-40 min to obtain solution I. The ratio of epoxy resin A to ethyl acetate is 1 g: (6~12) mL; the mass ratio of multi-walled carbon nanotubes to modified nano-silica particles is 1: (10~50); the ratio of silver powder, silane coupling agent and modified nano-silica is (0~10) g: 1 mL: (1~6) g; the silane coupling agent includes, but is not limited to, 3-aminopropyltriethoxysilane (silane coupling agent KH-550), 3-aminopropyltrimethoxysilane (silane coupling agent KH-540) or bisaminosilane (KH-792); 3. Add epoxy resin B, PDMS and its matching curing agent to solution I obtained in step 2, and magnetically stir for 2-4 hours at room temperature and a rotation speed of 800 r / min to obtain solution II; The mass ratio of epoxy resin B to epoxy resin A is 1:(2~5); the dosage ratio of PDMS to epoxy resin A is 1 mL:2 g; and the volume ratio of PDMS to its curing agent is (5~20):1. 4. Spray the solution II obtained in step 3 evenly onto the surface of the substrate at a distance of 10-15 cm. Then heat and cure the sample formed by spraying to obtain a conductive self-healing Ag / PDMS coating with dustproof properties.

[0027] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading this description, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0028] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications in the art, unless otherwise stated.

[0029] I. Preparation of a conductive self-healing Ag / PDMS coating with dust-proof properties Example 1 1. Place 3 g of nano silica particles (particle size of 20 nm) in 50 mL of anhydrous ethanol and ultrasonically disperse for 5 min. Then add 1 mL of octadecyltrichlorosilane to the dispersion and magnetically stir for 2 h in a water bath at 60 °C and a speed of 800 r / min. After washing with anhydrous ethanol and drying, repeat the washing and drying steps once to obtain modified nano silica particles.

[0030] 2. Add 1 g of epoxy resin A (purchased from Kunshan Yituo Composite Materials Co., Ltd., item number E51) to 8 mL of ethyl acetate and stir with a glass rod to dissolve the epoxy resin A in the ethyl acetate. Then add 0.03 g of multi-walled carbon nanotubes and 0.3 g of the modified nano-silica particles prepared in step 1. Sonicate the mixture for 5 min at 30℃, 200 W power and 30 kHz frequency. Then add 0.2 mL of silane coupling agent KH-550 and sonicate the mixture for 20 min at 30℃, 200 W power and 30 kHz frequency to obtain solution I.

[0031] 3. Add 0.5 g of epoxy resin B (purchased from Kunshan Yituo Composite Materials Co., Ltd., item number E51) and 0.5 mL of PDMS and its matching curing agent (PDMS:curing agent mass ratio of 10:1, purchased from Dow Corning, item number: Sylgard 184) to solution I obtained in step 2, and magnetically stir for 2 h at room temperature and a rotation speed of 800 r / min to obtain solution II.

[0032] 4. Load Solution II into the spray gun, connect the air valve to the spray gun, and spray Solution II onto the aluminum substrate at a distance of 10 cm. Place the sprayed sample on a heating table and heat it at 80°C for 2 hours to obtain a conductive self-healing Ag / PDMS coating with dustproof properties.

[0033] Example 2 The difference from Example 1 is that 0.3 g of silver powder is added in step 2, the magnetic stirring time in step 3 is different, and the spraying distance in step 4 is different.

[0034] 1. Place 3 g of nano-silica particles in 50 mL of anhydrous ethanol and ultrasonically disperse for 5 min. Then add 1 mL of octadecyltrichlorosilane to the dispersion and magnetically stir for 2 h in a 60℃ water bath at 800 r / min. Wash with anhydrous ethanol and dry. Repeat the washing and drying steps once to obtain modified nano-silica particles.

[0035] 2. Add 1 g of epoxy resin A to 8 mL of ethyl acetate and stir with a glass rod to dissolve the epoxy resin A in the ethyl acetate. Then add 0.03 g of multi-walled carbon nanotubes and 0.3 g of the modified nano-silica particles prepared in step 1. Sonicate the mixture at 30°C, 200 W power, and 30 kHz for 5 min. Then add 0.3 g of silver powder and 0.2 mL of silane coupling agent KH-550 and sonicate the mixture at 30°C, 200 W power, and 30 kHz for 20 min to obtain solution I.

[0036] 3. Add 0.5 g of epoxy resin B and 0.5 mL of PDMS and its matching curing agent (PDMS:curing agent mass ratio is 10:1) to solution I obtained in step 2, and magnetically stir for 4 h at room temperature and a rotation speed of 800 r / min to obtain solution II.

[0037] 4. Load Solution II into the spray gun, connect the air valve to the spray gun, and spray Solution II onto the aluminum substrate at a distance of 12 cm. Place the sprayed sample on a heating table and heat it at 80°C for 2 hours to obtain a conductive self-healing Ag / PDMS coating with dustproof properties.

[0038] Example 3 The difference from Example 1 is that 0.5 g of silver powder is added in step 2, the magnetic stirring time in step 3 is different, and the spraying distance in step 4 is different.

[0039] 1. Place 3 g of nano-silica particles in 50 mL of anhydrous ethanol and ultrasonically disperse for 5 min. Then add 1 mL of octadecyltrichlorosilane to the dispersion and magnetically stir for 2 h in a 60℃ water bath at 800 r / min. Wash with anhydrous ethanol and dry. Repeat the washing and drying steps once to obtain modified nano-silica particles.

[0040] 2. Add 1 g of epoxy resin A to 8 mL of ethyl acetate and stir with a glass rod to dissolve the epoxy resin A in the ethyl acetate. Then add 0.03 g of multi-walled carbon nanotubes and 0.3 g of the modified nano-silica particles prepared in step 1. Sonicate the mixture at 30°C, 200 W power, and 30 kHz for 5 min. Then add 0.5 g of silver powder and 0.2 mL of silane coupling agent KH-550 and sonicate the mixture at 30°C, 200 W power, and 30 kHz for 20 min to obtain solution I.

[0041] 3. Add 0.5 g of epoxy resin B and 0.5 mL of PDMS and its matching curing agent (PDMS:curing agent mass ratio is 10:1) to solution I obtained in step 2, and magnetically stir for 3 h at room temperature and a rotation speed of 800 r / min to obtain solution II.

[0042] 4. Load Solution II into the spray gun, connect the air valve to the spray gun, and spray Solution II onto the aluminum substrate at a distance of 15 cm. Place the sprayed sample on a heating table and heat it at 80°C for 2 hours to obtain a conductive self-healing Ag / PDMS coating with dustproof properties.

[0043] Example 4 The difference from Example 1 is that in step 2, 0.7 g of silver powder is added.

[0044] 1. Place 3 g of nano-silica particles in 50 mL of anhydrous ethanol and ultrasonically disperse for 5 min. Then add 1 mL of octadecyltrichlorosilane to the dispersion and magnetically stir for 2 h in a 60℃ water bath at 800 r / min. Wash with anhydrous ethanol and dry. Repeat the washing and drying steps once to obtain modified nano-silica particles.

[0045] 2. Add 1 g of epoxy resin A to 8 mL of ethyl acetate and stir with a glass rod to dissolve the epoxy resin A in the ethyl acetate. Then add 0.03 g of multi-walled carbon nanotubes and 0.3 g of the modified nano-silica particles prepared in step 1. Sonicate the mixture at 30°C, 200 W power, and 30 kHz for 5 min. Then add 0.7 g of silver powder and 0.2 mL of silane coupling agent KH-550 and sonicate the mixture at 30°C, 200 W power, and 30 kHz for 20 min to obtain solution I.

[0046] 3. Add 0.5 g of epoxy resin B and 0.5 mL of PDMS and its matching curing agent (PDMS:curing agent mass ratio is 10:1) to solution I obtained in step 2, and magnetically stir for 2 h at room temperature and a rotation speed of 800 r / min to obtain solution II.

[0047] 4. Load Solution II into the spray gun, connect the air valve to the spray gun, and spray Solution II onto the aluminum substrate at a distance of 10 cm. Place the sprayed sample on a heating table and heat it at 80°C for 2 hours to obtain a conductive self-healing Ag / PDMS coating with dustproof properties.

[0048] Example 5 The difference from Example 1 is that in step 2, 1 g of silver powder is added.

[0049] 1. Place 3 g of nano-silica particles in 50 mL of anhydrous ethanol and ultrasonically disperse for 5 min. Then add 1 mL of octadecyltrichlorosilane to the dispersion and magnetically stir for 2 h in a 60℃ water bath at 800 r / min. Wash with anhydrous ethanol and dry. Repeat the washing and drying steps once to obtain modified nano-silica particles.

[0050] 2. Add 1 g of epoxy resin A to 8 mL of ethyl acetate and stir with a glass rod to dissolve the epoxy resin A in the ethyl acetate. Then add 0.03 g of multi-walled carbon nanotubes and 0.3 g of the modified nano-silica particles prepared in step 1. Sonicate the mixture at 30℃, 200 W power and 30 kHz frequency for 5 min. Then add 1 g of silver powder and 0.2 mL of silane coupling agent KH-550 and sonicate the mixture at 30℃, 200 W power and 30 kHz frequency for 20 min to obtain solution I.

[0051] 3. Add 0.5 g of epoxy resin B and 0.5 mL of PDMS and its matching curing agent (PDMS:curing agent mass ratio is 10:1) to solution I obtained in step 2, and magnetically stir for 2 h at room temperature and a rotation speed of 800 r / min to obtain solution II.

[0052] 4. Load Solution II into the spray gun, connect the air valve to the spray gun, and spray Solution II onto the aluminum substrate at a distance of 10 cm. Place the sprayed sample on a heating table and heat it at 80°C for 2 hours to obtain a conductive self-healing Ag / PDMS coating with dustproof properties.

[0053] II. Performance Testing of Conductive Self-Healing Ag / PDMS Coating with Dust-Repellent Properties The performance of the conductive self-healing Ag / PDMS coatings with dustproof properties prepared in Examples 1 to 5 is tested below, with the original aluminum sheet (1060Al) and PMMA used as control experiments.

[0054] Table 1. Performance test results of different coatings

[0055] 1. Coating morphology characterization The morphology of the conductive self-healing Ag / PDMS coatings with dustproof properties prepared in Examples 3 and 5 was characterized by scanning electron microscopy.

[0056] The results are as follows Figure 1 As shown, large, continuous, dense epoxy resin layers (EP layers) with multi-scale micro / nano structures can be observed in the lower-magnification SEM images of the coating. These dense EP layers consist of numerous protrusions and pits. Higher-magnification images further reveal even smaller, more intricate micro / nano structures distributed on these protrusions and pits, forming even finer-scale protrusions and pits. These protrusions and pits are formed by the aggregation of modified SiO2 nanoparticles, MWCNTs, and Ag powder added to the coating. These micro-protrusion structures significantly reduce the contact area between the coating surface and the particles, thereby further reducing the van der Waals forces generated during the contact.

[0057] 2. Roughness test After the coating has been sprayed and cured, a surface roughness tester was used to test the surface roughness of the conductive self-healing Ag / PDMS coatings prepared in Examples 1 to 5, as well as the original aluminum sheet and acrylic sheet samples of the control experiment. During the test, multiple sampling points were selected in the flat area at the center of the sample and the average value was taken to ensure that the test conditions were consistent and the data were accurate and reliable.

[0058] The test results are shown in Table 1. The surface roughness of the Ag / PDMS coating prepared by this method reached 5.1~6.8 μm, which is much higher than that of the original aluminum sheet (0.4 μm) and acrylic sheet (0.87 μm). This indicates that after modification by combining multi-walled carbon nanotubes with modified nano-silica, the coating successfully constructed a uniform micro-rough structure. This multi-level rough structure can form a synergistic effect with the low surface energy characteristics of PDMS, which is an important structural basis for the coating to achieve excellent superhydrophobic and dustproof performance.

[0059] 2. Surface wettability test Water contact angle measurements were performed on the dustproof conductive self-healing Ag / PDMS coatings prepared in Examples 1-5, as well as the original aluminum sheet and acrylic sheet samples from the control experiment, using a contact angle meter to characterize the surface wetting properties of the coatings. The test room temperature was kept constant at 25°C, and deionized water was used as the test medium, with a single water droplet injection volume set to 5 μL. To reduce test errors, five different locations on the surface of each coating sample were randomly selected for testing, and the average value of the tests was taken as the water contact angle data for that sample.

[0060] The test results are shown in Table 1 and Figure 2 As shown, compared with the control group, the water contact angles of the Ag / PDMS coatings with different silver powder contents in all five groups were greater than 150°, and all exhibited superhydrophobic properties. There was no significant difference in the contact angle values ​​among the samples, and the overall fluctuation range was extremely small. This indicates that within the experimental range, changes in the amount of silver powder added have almost no effect on the wetting state of the coating surface, and the silver powder content has a negligible impact on the wetting characteristics of this composite coating surface.

[0061] 3. Conductivity test The sheet resistance of the dustproof conductive self-healing Ag / PDMS coatings prepared in Examples 1-5, as well as the original aluminum sheet and acrylic sheet samples from the control experiment, was measured using a sheet resistance meter. The differences in conductivity of the coatings were directly characterized by the sheet resistance values. The test environment was a room temperature of 25℃ and constant indoor humidity. Before the test, all coating samples were placed in a dust-free environment and allowed to stand for 30 minutes to eliminate test interference caused by surface dust and ambient temperature and humidity. During the test, five different test areas were evenly selected on the surface of each coating sample for testing. After removing abnormal data, the average value was taken as the final sheet resistance of the sample to ensure the accuracy and repeatability of the test data.

[0062] The test results are shown in Table 1 and Figure 3As shown, the original aluminum sheet exhibits good conductor properties, while the acrylic sheet is completely insulating. The Ag / PDMS coating prepared by this method, however, has a sheet resistance between that of a conductor and an insulator, exhibiting stable semiconductor conductivity. This is due to the continuous conductive network constructed by multi-walled carbon nanotubes within the system, which effectively dissipates accumulated static electricity on the surface, reducing electrostatic adsorption of dust at its source and endowing the coating with excellent electrostatic dissipation and dust-proof capabilities. Furthermore, as the silver powder content increases, the sheet resistance of the Ag / PDMS coating continuously decreases, and its conductivity gradually increases.

[0063] 4. Self-healing performance test The conductive self-healing Ag / PDMS coatings with dustproof properties prepared in Examples 1 to 5, as well as the original aluminum sheet and acrylic plate samples of the control experiment, were treated with a plasma cleaner to simulate chemical damage to the coating. Subsequently, each sample was heated at 150°C and then cooled naturally. The water contact angle of the sample after cooling was still greater than 140° as the criterion for effective single self-healing. The ultimate self-healing cycle test was carried out on each sample in turn to evaluate the cyclic self-healing stability of the coating.

[0064] The test results are shown in Table 1 and Figure 4 As shown, the original aluminum sheet and acrylic plate lack an organic elastic matrix and therefore do not possess self-healing capabilities. The coatings in Examples 1-4 achieved a maximum self-healing cycle of 6 times, while the coating in Example 5 achieved more than 6 cycles. All coating samples exhibited excellent and stable self-healing performance. Furthermore, the addition of Ag powder further enhanced the coating's tolerance to repeated repairs, maintaining its dust-proof and hydrophobic properties for a long time. Moreover, even after multiple plasma-chemical damage events, the water contact angle of all coatings recovered to nearly 150° after each thermal repair, essentially returning to the initial superhydrophobic level without significant degradation. This demonstrates that the Ag / PDMS conductive composite coating prepared by this method possesses excellent thermally driven self-healing capabilities and good cyclic stability, effectively repairing surface chemical damage and maintaining its superhydrophobic and dust-proof properties for a long time.

[0065] 5. Sandpaper wear cycle life test The wear resistance and long-term dustproof performance of each sample were characterized by sandpaper abrasion cycle test. The operation procedure for a single abrasion cycle was as follows: the conductive self-healing Ag / PDMS coating with dustproof properties prepared in Examples 1 to 5 was applied to the sandpaper surface with the coated side facing down. A weight was placed above the sample to apply constant pressure, and the sample and the weight were moved 10 cm in the positive direction of the scale. Then the sample was rotated 90° counterclockwise and moved 10 cm in the opposite direction to complete one complete abrasion cycle. The criterion for retaining effective wear resistance and protection performance was that the water contact angle of the coating remained above 140° after wear.

[0066] The test results are shown in Table 1. The Ag / PDMS coating prepared by this method can withstand more than 40 standard sandpaper abrasion cycles and can still maintain ultra-high hydrophobic and dustproof performance under multiple mechanical abrasions. This fully demonstrates that the composite coating has excellent mechanical wear resistance and long-term dustproof performance due to the synergistic effect of its unique micro-rough structure and flexible elastic matrix.

[0067] 6. Dust removal performance test To visually evaluate the surface dustproof and self-cleaning performance of coatings with different substrates and silver powder content, static dust rolling dust removal comparison experiments were conducted using conductive self-healing Ag / PDMS coatings with dustproof properties prepared in Examples 1 to 5, as well as original aluminum sheets and acrylic sheets from the control experiment. This experiment employed a self-made sample flipping dust removal testing device (assembled from an R-axis manual high-precision rotating platform (RSP60-L, purchased from Shenzhen Huike Pneumatic Precision Machinery Co., Ltd.), a 3D printing platform, and a 3D printing base; the R-axis manual high-precision rotating platform was fixed to the 3D printing platform, which in turn was fixed to the 3D printing base). The experimental environment was controlled at room temperature of 25℃ and relative humidity of 50%. Standard simulated dust was used for testing, ensuring uniform dust distribution and range, and eliminating external environmental interference. The specific test steps are as follows: The sample to be tested is fixed flat on the R-axis manual high-precision rotating platform. An equal amount of simulated dust (20 μm silica powder) is evenly spread on the surface of each sample using a quantitative powder spreader to ensure that the dust coverage thickness and dust distribution of all sample surfaces are consistent. Then, the R-axis manual high-precision rotating platform is slowly rotated at a constant rate, and the dust falling state on the sample surface is observed in real time. 1) Record the critical tilt angle corresponding to when the dust begins to slide off on its own in a large area, which is the dust roll-off angle. The dust prevention and self-cleaning ability of each sample surface is judged by the size of the roll-off angle. Each group of samples is tested 3 times, and the average roll-off angle is taken as the final experimental data. 2) After the sample is rotated to the critical tilt angle and the dust has fully slid off and stabilized, the mass of residual dust on the sample surface is weighed. Combined with the initial dust mass, the dust removal efficiency of each group of samples is calculated. Each group of samples is tested 3 times and the average value is taken to ensure that the test data is accurate and reliable.

[0068] The roll angle test results are as follows Figure 5As shown, compared with untreated aluminum sheets (1060Al) and untreated PMMA smooth substrates, Ag / PDMS composite coatings with different silver powder contents all have lower dust removal angles, proving that the dustproof, conductive, and self-healing Ag / PDMS coatings prepared by this method have excellent lunar dust protection performance. The dust removal efficiency test results are shown in Table 1. The original aluminum sheet has a dust removal efficiency of less than 10% and extremely poor dustproof and self-cleaning performance. The acrylic sheet's dust removal efficiency is only maintained at 50%~60%, with limited dustproof effect. The coating in Example 1 has a dust removal efficiency of 30%~40%, which is not significantly better than that of pure acrylic sheet. However, the dust removal efficiency of the coating after doping with silver powder is greatly improved, reaching more than 70%. Under optimized ratio, the coating's dust removal efficiency even exceeds 85%. This fully demonstrates that the introduction of silver components can effectively synergistically modify the low surface energy rough structure constructed by silica and PDMS, significantly improve the coating's dust removal ability and self-cleaning dustproof performance, and has an overwhelming advantage in lunar dust protection compared to traditional aerospace substrates.

[0069] 7. Adhesion test A silica-particle-modified AFM probe (CONTV-A, purchased from Bruker (Beijing) Technology Co., Ltd., catalog number: P-3247) was used to test the micro-adhesion of the dust-resistant conductive self-healing Ag / PDMS coatings prepared in Examples 1 and 5, as well as the control group acrylic sheet samples. A 5 μm × 5 μm observation area was selected on the surface of each sample, and force-displacement curves were acquired using a 16 × 16 pixel dot matrix. The adhesion force spectrum was processed by Gaussian fitting, and the mean value of the fitted value was used as the evaluation basis for the micro-adhesion of a single region. To ensure data reliability, multiple micro-regions of each group of samples were selected for repeated testing to measure the adhesion force between the silica particles and the coating surface.

[0070] The test results are shown in Table 1. Due to their high surface energy or lack of specific microscopic protection, the original aluminum sheet and acrylic sheet exhibited significant microscopic adhesion forces, with the PMMA acrylic sheet showing an average adhesion force of 95.86 nN. The coating in Example 1 showed a significantly reduced average adhesion force to 63.17 nN, and the coating in Example 5 further decreased to 24.88 nN. All coating samples demonstrated excellent and stable anti-adhesion performance. Furthermore, the addition of Ag powder further constructed a richer micro / nano rough structure, thereby minimizing the actual contact area between the surface and lunar dust particles and maximally weakening microscopic van der Waals forces. Moreover, even considering the variations in microscopic morphology within the test area, the adhesion force values ​​of all coatings showed a high degree of concentration in the spectral data of the 16×16 force curves. The Gaussian fitting curves exhibited complete peak shapes without significant data dispersion or abnormal fluctuations. This demonstrates that the Ag / PDMS conductive composite coating prepared by this method possesses excellent microscopic anti-dust adhesion ability and good microscopic morphology uniformity, which can effectively reduce surface van der Waals forces and maintain its superhydrophobic and dustproof properties for a long time.

[0071] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A method for preparing a conductive self-healing Ag / PDMS coating with dustproof properties, characterized in that, Epoxy resin A is dissolved in ethyl acetate, and multi-walled carbon nanotubes, modified nano-silica particles, silane coupling agent, epoxy resin B, and polydimethylsiloxane and its curing agent are added sequentially and mixed evenly. The mixture is then sprayed to obtain a conductive self-healing Ag / PDMS coating with dustproof properties.

2. The method for preparing the dustproof conductive self-healing Ag / PDMS coating according to claim 1, characterized in that, The modified nano-silica particles are prepared by dispersing nano-silica particles in anhydrous ethanol, adding a silane modifier, mixing, washing, and drying to obtain modified nano-silica particles.

3. The method for preparing the conductive self-healing Ag / PDMS coating with dustproof properties according to claim 2, characterized in that, The silane modifier is octadecyltrichlorosilane or fluorosilane.

4. The method for preparing the conductive self-healing Ag / PDMS coating with dustproof properties according to claim 2, characterized in that, The ratio of nano-silica particles to anhydrous ethanol is 1 g: (8~20) mL, and the ratio of nano-silica particles to silane modifier is (2.5~4) g: 1 mL.

5. The method for preparing the conductive self-healing Ag / PDMS coating with dustproof properties according to claim 1, characterized in that, Add silver powder before adding the silane coupling agent.

6. The method for preparing a conductive self-healing Ag / PDMS coating with dustproof properties according to any one of claims 1 to 5, characterized in that, The ratio of epoxy resin A to ethyl acetate is 1 g: (6~12) mL; the mass ratio of multi-walled carbon nanotubes to modified nano-silica particles is 1: (10~50); the ratio of silane coupling agent to modified nano-silica is 1 mL: (1~6) g; the mass ratio of epoxy resin B to epoxy resin A is 1: (2~5); and the ratio of polydimethylsiloxane to epoxy resin A is 1 mL: 2 g.

7. The method for preparing a conductive self-healing Ag / PDMS coating with dustproof properties according to any one of claims 1 to 5, characterized in that, The silane coupling agent is 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, or bisaminosilane.

8. The method for preparing a conductive self-healing Ag / PDMS coating with dustproof properties according to any one of claims 1 to 5, characterized in that, After spraying, the resulting sample is heated and cured.

9. A conductive self-healing Ag / PDMS coating with dustproof properties prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the dustproof conductive self-healing Ag / PDMS coating of claim 9 in the preparation of lunar exploration space equipment, detectors, rovers or spacesuits.

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