Interpenetrating network type S-MPO / PDMS self-repairing super-hydrophobic coating and preparation method thereof

Abstract

The invention discloses an interpenetrating network type S-MPO / PDMS self-repairing super-hydrophobic coating and a preparation method thereof, and relates to the technical field of hydrophobic material preparation, the super-hydrophobic coating comprises a modified super-hydrophobic monomer, polydimethylsiloxane and micron silica, the modified super-hydrophobic monomer and the polydimethylsiloxane form an interpenetrating three-dimensional network structure, and the modified super-hydrophobic monomer and the polydimethylsiloxane form an interpenetrating three-dimensional network structure. And micron silicon dioxide is dispersed in the coating. The preparation method of the interpenetrating network type S-MPO / PDMS self-repairing super-hydrophobic coating comprises the following steps: S1, preparing a super-hydrophobic monomer through a photocatalytic click chemical reaction; s2, carrying out hydrolysis modification on the super-hydrophobic monomer to obtain a modified super-hydrophobic monomer; s3, mixing the modified super-hydrophobic monomer, polydimethylsiloxane, micron SiO2 and a curing agent to prepare a coating solution; and S4, heating and curing by stages after coating. According to the invention, a synergistic effect mechanism of an interpenetrating network and micron SiO2 is adopted, so that the super-hydrophobicity, self-repairing capability and high adhesive force of the coating are realized, and good thermal stability, acid resistance and wear resistance are shown.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrophobic material preparation, in particular to a kind of interpenetrating network type S-MPO / PDMS self-repairing super-hydrophobic coating and preparation method thereof. BACKGROUND

[0002] Super-hydrophobic coating has shown wide application prospects in many fields due to its unique performance. Its excellent antifouling ability makes it difficult for stains to adhere to the coating surface, making it easy to clean and maintain. For example, self-cleaning glass uses this technology, greatly reducing the frequency and cost of manual cleaning. At the same time, the water-repellent performance of super-hydrophobic coating is also very outstanding, which can effectively prevent water penetration, so that waterproof outdoor equipment can still maintain dry and comfortable in harsh weather conditions. In addition, its wear-resistant characteristics further prolong the service life of the coating and improve the durability of the product. Therefore, super-hydrophobic coating plays an irreplaceable role in self-cleaning glass, anti-fog lenses, waterproof outdoor equipment and other fields.

[0003] However, the current super-hydrophobic coating still has the following significant defects in practical application. First, the loss of hydrophobic material on the surface of the coating due to mechanical wear or chemical corrosion causes the hydrophobic performance to decline rapidly, and the super-hydrophobic state cannot be maintained for a long time, which lacks durability. Second, the self-repairing mechanism of the coating relies on complex external stimuli (such as light, pH change), and existing technologies trigger the migration of low surface energy substances to repair damage through temperature, light or pH change, but such stimuli are difficult to control stably in actual environment, and the repair efficiency is limited. The interfacial adhesion between the coating and the substrate is weak, and it is easy to fall off due to external force. In addition, although traditional low surface energy substances (such as long fluorinated alkyl chains) have strong hydrophobicity, they have biological accumulation and environmental toxicity, which do not meet the green and environmentally friendly trend. Finally, the interfacial adhesion between the coating and the substrate is weak, and the micro-nano rough structure is easy to be damaged by external force and lose its effectiveness, which lacks effective self-repairing network design, resulting in poor structural stability. Therefore, it is urgent to develop a super-hydrophobic coating technology that is simple to prepare, environmentally friendly and has high self-repairing ability. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide an interpenetrating network type S-MPO / PDMS self-repairing super-hydrophobic coating and a preparation method thereof, which solves the problems of insufficient durability of super-hydrophobic coating, dependence on external stimuli for self-repairing, environmental risk of fluorine-containing compounds and weak interfacial adhesion between coating and substrate.

[0005] To achieve the above-mentioned purpose, the technical solutions adopted by the present application are as follows: The application provides an interpenetrating network type S-MPO / PDMS self-repairing super-hydrophobic coating, characterized by comprising modified super-hydrophobic monomers, polydimethylsiloxane and micron-sized silicon dioxide; the modified super-hydrophobic monomers and the polydimethylsiloxane form an interpenetrating three-dimensional network structure, and the micron-sized silicon dioxide is dispersed in the coating; wherein the mass ratio of the polydimethylsiloxane to the modified super-hydrophobic monomers is 0.1-5:1; and the filling amount of the micron-sized silicon dioxide is 2-8 wt%.

[0006] Further, the modified super-hydrophobic monomers are generated by a photocatalytic click chemistry reaction of tetra(3-mercaptopropionic acid) pentaerythritol ester, γ-(methacryloyloxy)propyltrimethoxysilane and octadecene, and are modified by tetraethyl silicate hydrolysis to form organic-inorganic hybrid monomers with a Si-O-Si network structure; wherein the mass ratio of tetra(3-mercaptopropionic acid) pentaerythritol ester, γ-(methacryloyloxy)propyltrimethoxysilane and octadecene is 1:0.5-1:1-3 based on the total mass of the modified super-hydrophobic monomers.

[0007] The application further provides a preparation method of the above interpenetrating network type S-MPO / PDMS self-repairing super-hydrophobic coating, comprising the following steps: S1: preparing super-hydrophobic monomers: dispersing tetra(3-mercaptopropionic acid) pentaerythritol ester, γ-(methacryloyloxy)propyltrimethoxysilane and octadecene in an organic solvent, adding a photoinitiator, and reacting under light irradiation and heating, and then centrifuging and purifying with solvent to obtain the super-hydrophobic monomers; the organic solvent is tetrahydrofuran; and the photoinitiator is 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide. The reaction conditions in the step S1 are as follows: UV light irradiation at 50℃ for 1 hour, a centrifugation speed of 5000 r / min, a centrifugation time of 5-10 minutes, and the use of THF with the same volume as the reaction solvent for purifying three times, and centrifugation after stirring for 5 minutes each time.

[0008] S2: modifying the super-hydrophobic monomers: hydrolyzing the super-hydrophobic monomers with tetraethyl silicate under acidic conditions to generate modified super-hydrophobic monomers; the acidic conditions in the step S2 are adjusting the pH value to 3-5 by adding hydrochloric acid; and the mass ratio of the tetraethyl silicate to the super-hydrophobic monomers is 1:1.4-1.5. The hydrolysis reaction conditions in the step S2 are as follows: water bath reaction at 60℃ for 8 hours, and aging at room temperature for 24 hours after reaction.

[0009] S3: preparing coating solution: mixing the modified super-hydrophobic monomer, polydimethylsiloxane, micron-sized silica and curing agent to obtain a self-repairing super-hydrophobic coating solution; the filling amount of the micron-sized silica in the step S3 is 6wt%; the mass ratio of the polydimethylsiloxane to the modified super-hydrophobic monomer is 1:3. The step of mixing uniformly in the step S3 comprises: ultrasonic dispersion of the tetrahydrofuran solution of the modified super-hydrophobic monomer and the micron-sized silica, then adding the polydimethylsiloxane and magnetically stirring for 30 minutes, then continuously stirring for 3 hours after adding the silane curing agent, and finally ultrasonic dispersion for 10 minutes. The ultrasonic dispersion has a power of 200-300 W, a frequency of 40 kHz, and a time of 10-20 minutes; the magnetically stirring speed of adding the polydimethylsiloxane is 500-1000 r / min for 30 minutes; and the continuously stirring time of adding the silane curing agent is 3 hours.

[0010] S4: coating and curing: coating the self-repairing super-hydrophobic coating solution on the surface of the pretreated substrate, and performing stage heating and curing to form an S-MPO / PDMS self-repairing super-hydrophobic coating. The stage heating and curing step in the step S4 is: pre-curing at 80℃ for 30 minutes, and then completely curing at 120℃ for 2 hours.

[0011] Compared with the prior art, the present application has the following beneficial effects: (1) The modified super-hydrophobic monomer S-MPO is synthesized by photocatalytic click chemistry reaction in the present application, and the S-MPO forms an interpenetrating network with PDMS, and is matched with an appropriate amount of micron-sized SiO2, so that excellent super-hydrophobic performance is achieved, the static water contact angle is greatly improved, and a high hydrophobic angle can still be maintained after multiple sandpaper abrasions, and the abrasion resistance of the coating is significantly improved.

[0012] (2) The present application constructs a unique interpenetrating network structure, which endows the internal hydrophobic molecules (such as S-MPO) of the coating with the ability to migrate to the surface through molecular diffusion and Si-O-Si network reconstruction when damaged. The specific mechanism is: damage causes the local surface energy to increase, which drives the low surface energy molecules to diffuse along the polymer chain to the damage area, and rearranges under thermodynamic equilibrium, thereby improving the repair efficiency. The present application constructs a unique interpenetrating network structure, which endows the internal hydrophobic molecules (such as S-MPO) of the coating with the ability to migrate to the surface through molecular diffusion and Si-O-Si network reconstruction when damaged.

[0013] (3) The present application uses a fluorine-free long-chain alkane to avoid the bioaccumulation toxicity problem caused by traditional fluorine-containing compounds, which meets the relevant environmental protection standards and is safer and more reliable in use.

[0014] (4) The application enhances the cross-linking density of the coating layer, effectively repairs the micropore defects, and significantly improves the adhesion of the coating layer to the substrate by reasonably regulating the mass ratio of PDMS to S-MPO.

[0015] (5) The application can maintain super-hydrophobicity for a long time under high-temperature environment with less mass loss, can maintain stable performance under acidic conditions, and can completely restore the hydrophobic performance after alkaline damage by heating, thus showing good chemical stability. The interpenetrating network structure significantly improves the structural stability of the coating layer and reduces the damage of the micro-nano structure caused by external force.

[0016] (6) The application has a simple synthetic route and can be completed in only a few steps, and the PDMS content and SiO2 filling amount can be flexibly regulated to reduce the raw material cost, adapt to different substrate requirements, and be suitable for various large-scale production scenarios, thus having good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, which together with the embodiments of the application, serve to explain the application, and do not constitute a limitation of the application. Among them: Figure 1 It is an infrared spectrum comparison chart of tetra (3-mercaptopropionic acid) pentaerythritol ester, gamma-(methacryloyloxy) propyl trimethoxysilane before and after reaction with octadecene and the system after reaction; Figure 2 It is a Fourier transform infrared spectrum of the hydrolysis product of super-hydrophobic monomer (MPO) and tetraethyl orthosilicate (TEOS) and the cross-linking and solidification of Si-O-Si network structure after adding polydimethylsiloxane (PDMS); Figure 3 It is an X-ray diffraction (XRD) spectrum of the S-MPO / PDMS / SiO2 super-hydrophobic coating layer; Figure 4 It is a molecular structure schematic diagram of tetra (3-mercaptopropionic acid) pentaerythritol ester (MPO); Figure 5 It is a molecular schematic diagram of S-MPO / PDMS / SiO2 interpenetrating network structure, showing the three-dimensional cross-linking form of organic-inorganic hybrid monomer and PDMS; Figure 6 It is an X-ray photoelectron spectroscopy (XPS) full spectrum of the S-MPO / PDMS coating layer; Figure 7 It is a high-resolution XPS spectrum of C 1s orbit in the S-MPO / PDMS coating layer; Figure 8 It is a high-resolution XPS spectrum of Si 2p orbit in the S-MPO / PDMS coating layer; Figure 9 High resolution XPS spectrum of O 1s orbit of S-MPO / PDMS coating; Figure 10 High resolution XPS spectrum of S 2p orbit of S-MPO / PDMS coating; Figure 11 Surface distribution mapping of C, O, Si, S elements of S-MPO / PDMS coating; Figure 12 SEM micro-morphology of S-MPO coating without PDMS addition of Comparative Example 1; Figure 13 SEM micro-morphology of S-MPO / PDMS coating with PDMS addition of 2g of Example 2; Figure 14 SEM micro-morphology of S-MPO / PDMS coating with PDMS addition of 3g of Example 3; Figure 15 SEM micro-morphology of S-MPO / PDMS coating with PDMS addition of 4g of Example 4; Figure 16 SEM micro-morphology of S-MPO / PDMS coating with PDMS addition of 5g of Example 1; Figure 17 Relationship curve of influence of different mass ratios of PDMS and modified super-hydrophobic monomer on static water contact angle of coating; Figure 18 Comparison chart of static hydrophobic angle test results of S-MPO / PDMS coating under different contents of micron SiO2 fillers; Figure 19 Test results of surface roughness (Ra) of S-MPO / PDMS coating under different contents of micron SiO2 fillers; Figure 20 TG-DSC curve of S-MPO / PDMS coating; Figure 21 Variation curve of static contact angle of S-MPO / PDMS coating during 140℃ heat cycle treatment; Figure 22 Attenuation curve of static contact angle of S-MPO / PDMS super-hydrophobic coating after sandpaper friction cycle (0-100 times); Figure 23 Variation curve of hydrophobic angle of S-MPO / PDMS coating immersed in pH=1 acidic and pH=13 alkaline solutions; Figure 24 Test results of hydrophobic angle recovery performance of S-MPO / PDMS coating after chemical immersion-heat self-repairing cycle. DETAILED DESCRIPTION

[0018] The application is further illustrated below with reference to examples, which include but are not limited to the following examples.

[0019] Example 1 An interpenetrating network type S-MPO / PDMS self-repairing superhydrophobic coating includes superhydrophobic monomer (S-MPO), polydimethylsiloxane (PDMS) and micron-sized silicon dioxide (SiO2). The S-MPO is generated by photo-catalytic click chemistry reaction of pentaerythritol tetramercaptoacetate (PETMP), γ-(methacryloyloxy)propyltrimethoxysilane (γ-MPS) and octadecene (ODE), and is modified by hydrolysis of tetraethyl orthosilicate (TEOS) to form an organic-inorganic hybrid monomer with a Si-O-Si network structure. The PDMS and the S-MPO form an interpenetrating three-dimensional network at a mass ratio of 3:1, significantly improving the cross-linking density of the coating and repairing micropore defects; the micron-sized silicon dioxide is distributed in the coating at a filling amount of 6 wt%, and the micron-sized silicon dioxide, as a skeleton, cooperates with the nano-sized silicon dioxide generated by hydrolysis of TEOS to construct a micro-nano rough structure to improve the hydrophobic property. The combination realizes the superhydrophobic property with a static water contact angle of 152° through the synergistic effect of the components, and at the same time, endows the coating with the self-repairing function of recovering the hydrophobicity after alkaline damage through thermal repair and repairing the surface by migration of internal hydrophobic molecules after mechanical wear. The S-MPO is a short name of 'Siloxane-modified Mercaptopropionate-Olefin copolymer'.

[0020] Also provided is a preparation method of the above interpenetrating network type S-MPO / PDMS self-repairing superhydrophobic coating, including the following steps: S1 Preparation of superhydrophobic monomer (MPO): 9.75 g of pentaerythritol tetramercaptoacetate (PETMP), 4.95 g of γ-(methacryloyloxy)propyltrimethoxysilane (γ-MPS) and 15.15 g of octadecene (ODE) are dispersed in 60 mL of tetrahydrofuran (THF) solution, uniformly mixed after ultrasonic treatment for 10 min, 0.3 g of a photo initiator TPO is added, and the mixture is placed in a heat collecting type constant temperature electronic magnetic stirrer at 50°C and irradiated under UV light for 1 h; then the solution after UV irradiation is placed in a high-speed centrifuge at a speed of 5000 r / min for 5 min, the supernatant is removed and washed with THF solution, and the operation is repeated three times to obtain the superhydrophobic monomer MPO.

[0021] Preparation of S2 modified super-hydrophobic monomer (S-MPO): first, 6.03 g of MPO prepared in step S1 was dissolved in 60 ml of THF solution, and placed on a 60 ℃ heat collecting constant temperature electronic magnetic stirrer to mix uniformly, 4.16 g of tetraethyl orthosilicate (TEOS) and 0.144 ml of deionized water were added dropwise, a catalyst hydrochloric acid was added to adjust the pH to 3.5, and after water bath at 60 ℃ for 8 h, it was placed at room temperature for 24 h to obtain the modified super-hydrophobic monomer S-MPO.

[0022] S3 Preparation of self-repairing super-hydrophobic coating solution (S-MPO / PDMS): 20 mmol of super-hydrophobic monomer S-MPO was added to a THF solution containing 0 wt% SiO2, and ultrasonic dispersion was performed to obtain a mixed solution, 5 g of PDMS was added to the mixed solution, and after magnetic stirring for 30 min, ultrasonic dispersion was performed for 10 min to obtain a uniform self-repairing super-hydrophobic coating solution S-MPO / PDMS. Specifically, the ultrasonic dispersion power was 250 W, the frequency was 40 kHz, the time was 15 minutes, the stirring speed of the added polydimethylsiloxane was 750 r / min, the stirring time was 30 minutes, then a silane curing agent (such as tetraethyl orthosilicate curing agent) was added and continuously stirred for 3 hours, and finally ultrasonic dispersion was performed for 10 minutes.

[0023] S4 Coating and curing: the alumina sheet was ultrasonically cleaned with anhydrous ethanol and deionized water for three times, and then placed in a 50 ℃ electric heating air drying oven for drying; the self-repairing super-hydrophobic coating solution S-MPO / PDMS prepared in step S3 was loaded on the surface of the alumina ceramic sheet by spraying, and the sample was placed in an electric heating air drying oven, pre-cured at 80 ℃ for 30 min, and then cured at 120 ℃ for 2 h to obtain a S-MPO / PDMS self-repairing super-hydrophobic coating with an interpenetrating network molecular structure design, which is denoted as T4.

[0024] Example 2: The preparation process is basically the same as that of Example 1, the only difference is that when preparing S-MPO / PDMS, 5 g of PDMS is replaced by 2 g of PDMS, and the product is denoted as T1.

[0025] Example 3: The preparation process is basically the same as that of Example 1, the only difference is that when preparing S-MPO / PDMS, 5 g of PDMS is replaced by 3 g of PDMS, and the product is denoted as T2.

[0026] Example 4: The preparation process is basically the same as that of Example 1, the only difference is that when preparing S-MPO / PDMS, 5 g of PDMS is replaced by 4 g of PDMS, and the product is denoted as T3.

[0027] Example 5: The preparation process is basically the same as that of Example 1, the difference is only that when preparing S-MPO / PDMS, 0wt% of SiO2 is replaced by 2wt% of SiO2.

[0028] Example 6: The preparation process is basically the same as that of Example 1, the difference is only that when preparing S-MPO / PDMS, 0wt% of SiO2 is replaced by 4wt% of SiO2.

[0029] Example 7: The preparation process is basically the same as that of Example 1, the difference is only that when preparing S-MPO / PDMS, 0wt% of SiO2 is replaced by 6wt% of SiO2.

[0030] Example 8: The preparation process is basically the same as that of Example 1, the difference is only that when preparing S-MPO / PDMS, 0wt% of SiO2 is replaced by 8wt% of SiO2, the ultrasonic dispersion power is 300W, the dispersion time is 20 minutes, and the magnetic stirring speed is 1000r / min.

[0031] Comparative Example 1: The preparation process is basically the same as that of Example 1, the difference is only that when preparing S-MPO / PDMS, 5g of PDMS is replaced by 0g of PDMS, and the product is recorded as T0.

[0032] Comparative Example 2: The preparation process is basically the same as that of Example 1, the difference is only that when preparing S-MPO / PDMS, 5g of PDMS is replaced by 2g of PDMS, 6.03g of MPO is replaced by 0g of MPO, 0.144ml of deionized water is replaced by 0ml of deionized water, 4.16g of TEOS is replaced by 0g of TEOS, and the product is recorded as T5.

[0033] Based on the above examples, the following experiments were conducted: I. Element and structure analysis experiment: Taking the samples prepared by Examples 1-8 and Comparative Example 1 as examples, the functional group changes (-SH, C=C, Si-O-Si bond), element valence (C, Si, O, S), SiO2 crystallization state (amorphous), and element distribution (uniformity) were analyzed.

[0034] 1. Nicolet Is500 high-resolution Fourier infrared spectrum (FTIR, Fourier Transform Infrared Spectroscopy, Nicolet Is500) of China Thermo Scientific Company was used to characterize and analyze the functional groups and molecular structure characteristics of the super-hydrophobic functional monomer, and the scanning range was 500-4000cm -1 . The results are shown in Figure 1 .Figure 1 The infrared spectra of each substance before and after the reaction and the system after the reaction. As can be seen from the figure, the thiol-olefin click chemistry reaction mainly occurs at the mercapto group (-SH). In FT-IR, -SH usually shows symmetric stretching vibration absorption at 2600~2500 cm -1 . PETMP has a stretching vibration peak at 2568 cm -1 , indicating that the system contains a large amount of -SH. The decrease in the intensity of the peak indicates that -SH participates in the reaction, and the peak at this place in the system after the reaction disappears completely, indicating that the -SH group in the product is basically eliminated, and the mercapto-olefin click reaction is basically complete. At the same time, the reactants γ-MPS and ODE both have a stretching vibration absorption peak at 1695~1630 cm -1 . This peak is the stretching vibration absorption peak of carbon-carbon double bond (C=C), which completely disappears in the system after the reaction, indicating that C=C in the system has completely reacted. At the same time, -SH in the system after the reaction completely disappears, indicating that C=C in the reaction process has reacted with -SH, and there is no addition reaction between C=C, and no by-product is generated. The reactant γ-MPS has a relatively wide stretching vibration absorption peak at 1080 cm -1 . Generally, 1080 cm -1 is the stretching vibration absorption of Si-O-C in infrared spectroscopy. No obvious stretching vibration peak of -OH is found at 3650~3200 cm -1 before and after the reaction, indicating that no hydrolysis reaction of γ-MPS molecules occurs before and after the reaction, and no crosslinking reaction occurs between the prepared MPO molecules. In summary, the superhydrophobic and superoleophilic organic monomer MPO is successfully prepared by photocatalytic click chemistry reaction, and no by-product is generated in the reaction process, indicating that the organic functional monomer with superwettability can be efficiently prepared by this method.

[0035] Figure 2 The Fourier infrared spectra of MPO and TEOS hydrolysis and the crosslinking and solidification of Si-O network after the addition of PDMS in the system. As can be seen from the figure, TEOS has an anti-symmetric stretching vibration peak at 1072 cm -1 . This is the infrared absorption peak of Si-O-C group. After the hydrolysis of MPO molecules, the intensity of the peak decreases, but it does not completely disappear, indicating that the hydrolysis of MPO molecules is not complete. At the same time, a new peak appears at 1052 cm -1 . This is the stretching vibration absorption peak of Si-O-Si, indicating that the coupling between MPO and the nanosilica (SiO2 NPs) generated by the hydrolysis of TEOS occurs after the hydrolysis of MPO molecules. At the same time, 3650~3200 cm -1There is a wider -OH stretching vibration peak, indicating that the SiO2 NPs generated by the hydrolysis of TEOS still contains a large amount of -OH on the surface of the system. By adding PDMS in the system, the -OH at 3650~3200 cm-1 in the FT-IR diagram disappears completely, and at the same time, a -Si-O-Si- anti-symmetrical stretching vibration peak is generated at 1012 cm -1 There is a -Si-O-Si- anti-symmetrical stretching vibration peak, indicating that the S-MPO and PDMS occur condensation reaction to generate S-MPO / PDMS product. In summary, by introducing SiO2 NPs generated by the hydrolysis of TEOS into the monomer structure of the photocatalytic product MPO, and then condensing PDMS with SiO2 NPs, S-MPO / PDMS with a complex interpenetrating network structure network can be formed. At the same time, since water is slightly soluble in THF solution, there is a part of MPO monomer that does not occur hydrolysis during the hydrolysis process, and the unhydrolyzed monomer can be wrapped in the coating by the interpenetrating network. When the coating is in contact with air for a long time or when the coating is damaged, the unhydrolyzed monomer can occur hydrolysis and crosslinking to form Si-O network to improve the adhesion of the coating, and at the same time, the hydrophobicity of the coating is repaired. The adhesion grade of the coating without adding PDMS is 2B, and the adhesion grade of the coating of the application is improved to 5B.

[0036] 2. The wide-angle X-ray diffractometer (XRD, X-ray diffraction, X'Pert PRO) of the Netherlands Panalytical Company was used to test the XRD of the sample in the scanning angle range of 5~95°, and the surface phase and composition of the super-hydrophobic coating were analyzed. Figure 3 The XRD pattern of the coating can be seen from the pattern, and the characteristic peak of Al2O3 appears in the commercially available Al2O3 substrate, indicating that there is Al2O3 with different crystal forms in the commercially available Al2O3 substrate. After spraying the S-MPO coating on the Al2O3 substrate, the XRD pattern of the sprayed coating is basically the same as that of the commercially available Al2O3 substrate, but there is no obvious characteristic peak in the sprayed S-MPO coating, indicating that the SiO2 in the coating mainly exists in the form of amorphous. At the same time, a large peak appears in the range of 25°~35°, and the nano-silicon dioxide generated by the hydrolysis of TEOS is usually amorphous non-crystalline nano-SiO2, indicating that the nano-SiO2 in the S-MPO coating may be amorphous non-crystal, and the coating needs to be further tested by XPS and the existing form of SiO2 crystal structure is further analyzed combined with the test results.

[0037] 3、Long-chain alkanes have good lipophilic and hydrophobic properties. Compared with traditional fluorinated materials, long-chain alkanes do not contain fluorine elements and can be decomposed by microorganisms, which are environmentally friendly. Therefore, long-chain alkanes are often used in the design of lipophilic and hydrophobic molecular structures. γ-MPS contains a carbon-carbon double bond (C=C) at one end, which can undergo a click reaction with the -SH group, and the other end can be hydrolyzed to generate a hydroxyl group (-OH), which can be adsorbed on an inorganic surface to form a strong bond. Based on this, the organic-inorganic hybrid superhydrophobic and superoleophilic monomer S-MPO molecular structure was designed, as shown in Figure 4 The four -SH groups on the PETMP are used as the cross-linking and curing points for thiol-alkene click reaction, and three long-chain ODE and γ-MPS molecules are introduced into the base molecule. Through click chemistry, a superhydrophobic organic monomer MPO is obtained, as shown in Figure 5 The γ-MPS chain on the MPO molecule is co-hydrolyzed with the TEOS molecule to graft the MPO molecule onto the nano-SiO2 surface generated by the hydrolysis of TEOS, forming an organic-inorganic hybrid superhydrophobic monomer S-MPO molecule. By introducing PDMS, the PDMS cross-links and cures to form a Si-O-Si network, and fills a certain amount of micron-sized silica to form a rough structure, an S-MOP / PDMS / SiO2 superhydrophobic coating with interpenetrating network structure can be obtained.

[0038] 4、The X-ray photoelectron spectroscopy (XPS, X-ray Photoelectron Spectroscopy, Thermo Scientific K-alpha) of Japan ULVAC-PHI Company was used for qualitative and quantitative analysis of the surface element composition, element valence state analysis and surface element chemical imaging analysis. The electron energy range of X-ray photoelectron spectroscopy is 0-1200 Ev, and the test temperature range is -100-800 ℃. The Avantage software was used for data processing such as smoothing and peak fitting of high-resolution spectra. Figure 6 The XPS full spectrum of the S-MPO / PDMS coating is shown, and the results show that there are C, Si, O, and S elements in the coating. As shown in Figure 7For the high resolution spectrum of C 1s region, three strong characteristic peaks were detected at 284.78 eV, 286.02 eV and 288.93 eV positions in the spectrum, in which the characteristic peaks at 284.78 eV and 288.93 eV positions correspond to C-C and C-Si bonds in the super-hydrophobic S-MPO / PDMS coating respectively, and the characteristic peak at 288.93 eV position may correspond to C-O or C-S bond. In which, the C-C bond is due to the introduction of long-chain alkane ODG in the coating by click reaction, and the presence of C-Si bond is introduced by the precursor PDMS, and the precursor PETMP contains both -COOR functional group and -SH functional group, so the characteristic peak at 288.93 eV position may be C-O bond introduced by -COOR group or C-S bond introduced by mercapto group. Figure 8 For the high resolution spectrum of Si 2p region, there are three obvious characteristic peaks at 100.58 eV, 101.49 eV and 102.50 eV positions, which correspond to Si-C, Si-OH and Si-O-Si bonds respectively. In which, the Si-C bond is introduced by the PDMS precursor. The Si-OH bond is due to the hydrolysis of one MPO molecule to produce three Si-OH, and part of the Si-OH exists after the condensation of SiO2 formed by the hydrolysis of TEOS. The existence of part of Si-OH can gradually occur intermolecular crosslinking and solidification in the subsequent process, so that the Si-O-Si network structure is formed between S-MPO molecules, and the adhesion of the coating is improved. The presence of Si-O-Si characteristic peak at 102.50 eV position indicates that a high degree of Si-OH condensation reaction occurs in the coating, and the crosslinking and solidification degree of the coating is high. Figure 9 For the high resolution spectrum of O 1s region, the characteristic peaks at 531.02 eV and 532.33 eV positions in the spectrum correspond to O-Si bond and O-C bond respectively, and the O-Si bond at 531 eV position usually corresponds to amorphous silicon dioxide. Combined with XRD analysis, it can be concluded that SiO2 in S-MPO exists in the form of amorphous non-crystalline. Figure 10 For the high resolution spectrum of S 2p region, the characteristic peaks at 162.29 eV and 163.47 eV positions in the spectrum correspond to C-S-C bond and S-H bond respectively, and the existence of S-H bond indicates that there is part of residual PETMP in the reactant. The existence of C-S-C bond indicates that ODE molecules and γ-MPS molecules are successfully introduced into PETMP molecules by click reaction. In summary, it is shown that the organic-inorganic hybrid S-MPO / PDMS coating is successfully prepared by photocatalytic click chemistry reaction.

[0039] 5. Qualitative elemental analysis of the sample surface was performed using an energy dispersive spectroscopy (EDS, Tescan Clara GMH) instrument. For example... Figure 11 As shown in the diagram, the elemental mapping of the S-MPO / PDMS coating reveals that C, O, Si, and S elements are continuously and uniformly distributed on the coating surface, indicating that the superhydrophobic S-MPO molecules are uniformly dispersed on the coating surface. The S element exhibits a network structure on the coating surface because silane condensation reactions occur between S-MPO molecules to form a silicon-oxygen network, further demonstrating the successful preparation of an organically modified superhydrophobic S-MPO / PDMS coating with an interpenetrating network structure via click chemistry.

[0040] II. Microscopic morphology observation experiment: The surface microstructure of the samples prepared in the PDMS content gradient groups (Examples 1-4) and Comparative Example 1 was observed using a field emission scanning electron microscope (SEM, Tescan Clara GMH) from FEI Corporation, USA. The accelerating voltage of the field emission scanning electron microscope was 5 keV, the electron beam current was 10 nA, and the optimal working distance was 8 mm.

[0041] like Figure 12-16 As shown, with the increase of PDMS content, the coating surface gradually changes from a porous structure to a dense structure, and the coating density increases. At the same time, with the increase of PDMS content, the rough structure of the coating surface decreases. Figure 12 The surface morphology of the coating T0 prepared in Comparative Example 1 without PDMS is shown. When PDMS is not added, the superhydrophobic coating surface exhibits numerous micropores. With increasing PDMS content, such as... Figure 13-16 The figures show the surface morphologies of coatings T1, T2, T3, and T4 when the PDMS doping concentrations are 2, 3, 4, and 5 g, respectively. The micropores on the coating surface gradually decrease, and the density of the coating gradually increases. Figure 15 As shown, when the PDMS content reaches 4g, no microporous structure exists on the coating surface. This is mainly because the presence of PDMS can improve the degree of cross-linking and curing of the coating. The coating surface first undergoes hydrolysis of MPO organic monomers with TEOS, producing silanol groups (Si-OH). The MPO organic monomers, through the hydrolysis of Si-OH with TEOS, generate... Figure 13As shown, when the PDMS content reaches 2 g, the organic-inorganic hybrid nano-silica particles S-MPO with hydrophobic properties, the micro- and nano-particles are agglomerated to form microparticles with papillary structure distributed on the surface of the coating to make the coating have hydrophobic properties. When the coating does not contain PDMS, the coating is only formed by the intermolecular condensation of silica sol to form a Si-O-Si network wrapping the S-MPO particles attached to the surface of the coating, the intermolecular crosslinking and curing degree of the silica sol is low, resulting in defects such as micropores on the surface of the coating. When a certain amount of PDMS is added to the coating, the PDMS molecules have a high crosslinking and curing degree, the intermolecular condensation reaction of the PDMS molecules can form a Si-O-Si network structure, and the PDMS molecules can be filled in the Si-O network formed by the silica sol to form a Si-O-Si coating with an interpenetrating network structure, which can repair the micropores and other defects in the coating and improve the density of the coating. However, as the PDMS content increases, as shown, the PDMS molecules will wrap the S-MPO particles with hydrophobic properties inside the coating, and when there is an excess of PDMS molecules, the hydrophobic MPO is completely filled in the PDMS, and the hydrophobic branched chain cannot migrate to the surface of the coating, at this time the surface energy of the coating is mainly the surface energy of the PDMS. After the PDMS wraps the nano-silica inside the coating, the rough structure on the surface of the coating is reduced, which may have a certain impact on the hydrophobic properties of the coating. Figure 15

[0042] III. Coating contact angle test experiment: The optical contact angle meter (DSA100, KRUSS) of Germany Dataphysics Company was used to test the contact angle of the sample. 5 μL of deionized water or oil droplets were dropped on the sample surface as test liquid, and the photos before and after the liquid droplets contacted the sample were recorded by a super high-speed optical camera. Then the contact angle value of the sample was measured by taking the baseline on the sample and the substrate surface. Each sample was measured 6 times, and the average value was taken as the final measurement value.

[0043] For example, the samples prepared by Examples 1-4 and Comparative Examples 1 and 2 were used to prepare S-MPO / PDMS self-repairing super-hydrophobic coatings with different PDMS contents and different SiO2 contents under the same conditions for comparison. As shown in Figure 17 The influence of the PDMS doping amount on the hydrophobic properties of the coating, with the increase of the PDMS content, the hydrophobic properties of the coating gradually decrease. When no PDMS is added to the coating, as shown in Figure 17 ​As shown, the hydrophobic angle of T0 can reach 149.5°, indicating that the organic-inorganic hybrid S-MPO coating prepared by click reaction has good hydrophobic performance. When the PDMS content is added to T1, the static water contact angle of the coating can reach 153.7°, and the coating has superhydrophobic performance. At the same time, it can be seen from the figure that when the mass ratio of MPO to PDMS is 3:1, the static water contact angle of the coating reaches 153.7° (T1), and the coating shows superhydrophobic performance. However, with the increase of the content of PDMS, the hydrophobic performance of the coating gradually decreases, and when the content of PDMS in the coating is T4, the static contact angle of the coating to water is only 131.4°, and the static contact angle of the coating gradually approaches the static contact angle of pure PDMS. The static contact angle of T5 coating to water is only 120°. Combined with the micro-morphology of the superhydrophobic coating, when the content of PDMS in the coating is low, the superhydrophobic organic-inorganic monomer S-MPO generated by hydrolysis and condensation can migrate and disperse on the surface of the coating, forming a micro-nano structure on the surface of the coating, providing a rough micro-nano structure with low surface energy for the coating, so the coating has excellent hydrophobic performance. With the increase of the content of PDMS, the hydrophobic performance of the coating gradually decreases, which may be due to the increase of the content of PDMS, the excess PDMS gradually wraps the MPO monomer with better hydrophobic performance, and at the same time, the nano-silicon dioxide generated by the hydrolysis of TEOS in the coating is less. With the increase of the content of PDMS, the SiO2 generated by the hydrolysis of TEOS cannot stack the micro-nano rough structure on the surface, so the hydrophobic performance of the coating gradually decreases and gradually approaches the hydrophobic performance of pure PDMS.

[0044] By adding PDMS in the coating, the crosslinking degree of the coating can be effectively improved, and the defects such as micropores in the coating can be repaired, but with the increase of the content of PDMS, the S-MPO particles with hydrophobic function are wrapped in the coating, resulting in the decrease of the hydrophobic performance of the coating, so by filling a certain amount of silica filler with a particle size of 1 μm in the coating, the hydrophobic performance of the coating is improved. For example, samples prepared in Examples 1 and 5-8, 2wt%, 4wt%, 6wt% and 8wt% of micron SiO2filler are added to the T4 coating of Example 1, and the influence law of the coating performance is studied. As Figure 18For the test results of the hydrophobic angle of the S-MPO / PDMS coating with different contents of micron SiO2filler, with the increase of the content of micron SiO2, the hydrophobicity of the coating gradually recovers, but with the continuous increase of the micron SiO2filler, the hydrophobicity of the coating shows a trend of first increasing and then decreasing. This is because when a certain amount of micron SiO2is added to the coating, the micron SiO2is filled in the PDMS, so that more hydrophobic S-MPO can migrate to the surface of the coating, and the presence of micron SiO2filler can provide an attachment site for nano S-MPO, and S-MPO is attached to the surface of micron SiO2to form a micro-nano rough structure, so at this time, with the increase of the content of SiO2, the hydrophobicity of the coating increases significantly, and when the content of SiO2is excessive, the excessive particles further agglomerate and accumulate, covering the micro-nano rough structure of the coating, so that the rough structure of the coating surface tends to be flattened, and the hydrophobicity of the coating gradually decreases. Therefore, when the content of SiO2is 6%, the static water contact angle of the coating reaches 152°, showing superhydrophobicity.

[0045] Four, roughness analysis experiment: Taking the samples prepared in Example 1 and Examples 5-8 as examples, a roughness analysis experiment was performed. As shown in Figure 19 When no micron SiO2filler is added, the surface of the coating is relatively flat, and the roughness is only 0.75 μm, and with the increase of the content of SiO2filler, the roughness of the coating increases significantly, and when the content of the filler is 8%, the surface roughness of the coating is 13.75 μm. When no micron filler is added, the surface of the coating is relatively flat, and with the increase of the content of the filler, the surface of the coating gradually accumulates micro-nano structures, and when the content of the filler is 6 wt%, the surface of the coating accumulates uniform micro-nano structures, and at this time, the hydrophobicity of the coating is the best, but with the increase of the content of SiO2, the excessive particles further agglomerate and accumulate, covering the micro-nano structures that have been formed, and the coating gradually tends to be flattened, and the hydrophobicity of the coating gradually decreases.

[0046] When the content of SiO2is 8 wt%, 300 W ultrasonic dispersion and 1000 r / min stirring are required to inhibit agglomeration, and at this time, the static water contact angle of the coating can still reach 148°, but the surface roughness increases to 13.75 μm, and the hydrophobicity is slightly lower than that of the 6 wt% group.

[0047] Five, thermal stability test experiment The differential scanning calorimeter (DSC) and thermogravimetric (TG) analyzer of the German Netzsch company (STA, Synchronous Thermal Analyzer, 449F5) were used to analyze the superhydrophobic superoleophilic coating, and the amount of superhydrophobic superoleophilic organic monomer grafted and the thermal stability of the coating were analyzed. The test was carried out in air, the heating rate was 5 ℃ / min, and the temperature range was 20-800 ℃.

[0048] In order to test the high temperature resistance of the coating, the TG-DSC curve of the coating prepared when the mass ratio of PDMS:MPO is 3:1 was tested by using a simultaneous thermal analyzer, and the coating was heat treated at 140 ℃ for different times. The thermal stability of the coating was characterized by measuring the change of the wetting angle value of the coating after heat treatment. Figure 20 For the TG-DSC curve of the coating, it can be seen that the TG curve of the coating is almost a parallel straight line within 150 ℃, at which time the coating has almost no mass change, and the mass loss rate of the coating is only 5% at 285 ℃, indicating that the three-dimensional network interpenetrating structure composed of Si-O-Si bonds has good thermal stability, which is mainly due to the high thermal stability of Si-O-Si bond. It can be known from the analysis of the DSC curve that the mass loss rate of the coating is 81.22% within the temperature range of 20~600 ℃, which is mainly due to the thermal decomposition of PDMS and the decomposition of the super-hydrophobic monomer on the surface of nano-silicon dioxide, indicating that a large number of organic functional groups with hydrophobic properties are grafted on the surface of SiO2 particles. At the same time, the remaining solid mass percentage of the coating is greater than the mass fraction of the micron SiO2 added, indicating that part of SiO2 is generated by the hydrolysis of TEOS. At 70~200 ℃, the TG curve decreases and the DSC curve does not change, which is due to the fact that S-MPO surface is grafted with ODE molecules, and the melting point of ODE is relatively low, resulting in a relatively low melting point of the prepared S-MPO molecules. Therefore, with the increase of temperature, part of the coating softens and releases heat. Therefore, in order to explore the influence law of the re-solidification of the coating after softening on the hydrophobicity of the coating, the coating was heated at 140 ℃ for a certain time and then cooled to room temperature, and the hydrophobicity of the coating was tested. As Figure 21 , the hydrophobic angle of the coating is still 153 ° after 240 min of heat treatment, and the coating can still be immersed in oil after 240 min of heat treatment, indicating that long-term thermal cycling will not cause the degradation of the hydrophobic organic molecules in S-MPO / PDMS molecules, and the coating has good thermal stability.

[0049] Six, wear resistance test experiment Taking the sample prepared in Example 8 as an example, the wear resistance of the coating was tested by using a sandpaper cycle friction experiment, and the hydrophobic angle of the coating was tested to characterize the wear resistance of the coating. 200 g of weight was pressed on the surface of 1000 mesh sandpaper, and the sandpaper was pressed on the surface of the coating. The sandpaper was dragged in one direction at a cycle of 10 cm. After each cycle of 10 times, the coating surface debris was removed with deionized water and dried, and the hydrophobic angle of the coating was tested.

[0050] The experimental results are as follows Figure 22As shown, the hydrophobic angle of the coating gradually decreases with the increase of the friction times within 100 friction cycles, and remains stable with the increase of the friction times after 100 cycles. The hydrophobic angle of the coating is still 148.6° after 200 cycles. This is mainly because the nano-SiO2 with hydrophobic function on the surface of the coating and the rough micro-nano structure constructed are worn off with the increase of the friction times within 100 cycles, resulting in the decrease of the hydrophobic performance of the coating. However, when the surface of the coating is worn off, the nano-SiO2 with hydrophobic function inside migrates to the surface of the coating to re-construct the coating with low surface energy. Therefore, the coating still has a hydrophobic angle of 149.3° after 100 friction cycles. With the increase of the friction times, the rough structure on the surface of the coating basically disappears, and the hydrophobic performance of the coating is mainly provided by the nano-SiO2 migrated to the surface. Therefore, the hydrophobic angle of the coating does not decrease significantly and remains stable around 148.6°. Microparticles are used to construct the rough structure, and nanoparticles are used to enhance the cross-linking.

[0051] In summary, the S-MPO / PDMS coating with interpenetrating network structure has good wear resistance and still exhibits a high hydrophobic angle after 200 friction cycles. At the same time, the coating exhibits excellent self-repairing performance. With the removal of the surface hydrophobic substances, the internal hydrophobic molecules migrate to the surface to realize the self-repairing function of the coating.

[0052] Seven, acid and alkali resistance test experiment For example, the sample prepared in Example 1, a sulfuric acid solution with a pH value of 3 and a potassium hydroxide solution with a pH value of 12 are configured, the molar concentration of the sulfuric acid solution is 0.005 mol / L, and the molar concentration of the potassium hydroxide solution is 0.01 mol / L. The solutions are dropped on the surface of the S-MPO / PDMS coating, and after standing for 2, 4, 6, 8 and 10 h, the surface solution is removed with anhydrous ethanol and deionized water and then dried. The hydrophobic angle of the coating at different immersion times is tested to determine the acid and alkali resistance of the coating. The test results are shown in Figure 23 As shown, under acidic conditions, the hydrophobic angle of the coating changes little, and even after 10 h of liquid drop on the surface, the hydrophobic performance of the coating does not decrease significantly, indicating that the coating has good acid resistance. Under alkaline conditions, the hydrophobicity of the coating decreases significantly. When the immersion time is 2 h, the hydrophobic angle of the coating decreases to 139.9°, and with the increase of the immersion time, the hydrophobic performance of the coating gradually decreases. When the immersion time is 8 h, the hydrophobic performance of the coating decreases significantly, and when the immersion time is 10 h, the hydrophobic angle of the coating is only 106.4°, and the coating gradually loses the hydrophobic performance.

[0053] Eight, self-repairing performance verification experiment As an example, the sample prepared by Example 1 and Example 8, in order to prove the self-repairing performance of the coating, the coating after immersed in alkaline condition for 4 h was heated at 120℃ for 2 h, and the hydrophobic angle of the coating was tested. The test results are shown in Table 2. Figure 24 As shown in Table 2, after multiple chemical immersion-heating cycles, the hydrophobic performance of the coating can be effectively restored and stabilized at about 150°. In summary, the S-MPO / PDMS coating with interpenetrating network structure has good chemical stability in acidic conditions, and in alkaline conditions, the hydrophobic molecules in the coating can migrate to the surface of the coating by heating the coating, and the coating exhibits self-repairing performance to restore the hydrophobic performance of the coating.

[0054] In summary, the present application prepares a super-hydrophobic functional monomer S-MPO by photocatalytic click chemistry reaction, constructs a low surface energy material with interpenetrating network structure by S-MPO and polydimethylsiloxane PDMS, fills micrometer silica SiO2, and constructs a micro-nano rough structure by micrometer SiO2 and S-MPO molecules. A super-hydrophobic coating with a contact angle greater than 150° is successfully prepared on the surface of an alumina substrate by spraying. The ratio of PDMS to S-MPO and the content of micrometer SiO2 have important influences on the mechanical stability, surface rough structure and hydrophobicity of the coating. The introduction of PDMS interpenetrating network structure can effectively increase the crosslinking degree of the coating and improve the adhesion of the coating. The performance of S-MPO / PDMS with interpenetrating network structure is tested, and the coating exhibits good thermal stability, chemical stability and wear resistance. The present application proposes a self-repairing mechanism of the coating, and the interpenetrating network molecular structure design can better protect the super-hydrophobic MPO molecules prepared by thiol-alkene click reaction. After the surface coating is damaged, the molecules with hydrophobic performance inside can migrate to the surface of the coating, so that the hydrophobic performance of the coating is restored. In alkaline conditions, a layer of hydrophilic substance is attached to the surface of the coating, which leads to a decrease in the hydrophobic performance of the coating. After heating, the molecules with hydrophobic performance in the interpenetrating network structure migrate to the surface of the coating, so that the hydrophobic performance of the coating is repaired. At the same time, in the friction experiment, after the surface hydrophobic molecules are lost, the internal hydrophobic molecules become surface hydrophobic molecules, so that the coating consistently maintains high hydrophobic performance.

[0055] The above examples are only one of the preferred embodiments of the present application and should not be used to limit the protection scope of the present application, but any modification or polishing without substantial meaning made within the main design idea and spirit of the present application, which still solves the technical problems consistent with the present application, should be included in the protection scope of the present application; the above examples can be repeatedly implemented by conventional techniques in the art, and the experimental data is real and reliable.

Claims

1. An interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating, characterized in that: The modified super-hydrophobic monomer, polydimethylsiloxane and micron-sized silica; the modified super-hydrophobic monomer and polydimethylsiloxane form an interpenetrating three-dimensional network structure, and the micron-sized silica is dispersed in the coating; wherein the mass ratio of polydimethylsiloxane to modified super-hydrophobic monomer is 0.1-5:1; and the filling amount of micron-sized silica is 2-8 wt%.

2. The interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating according to claim 1, characterized in that: The modified super-hydrophobic monomer is generated by photocatalytic click chemistry reaction of tetra(3-mercaptopropionic acid) pentaerythritol ester, γ-(methacryloyloxy) propyl trimethoxysilane and octadecene, and is modified by tetraethyl silicate hydrolysis to form an organic-inorganic hybrid monomer with Si-O-Si network structure; wherein the mass ratio of tetra(3-mercaptopropionic acid) pentaerythritol ester, γ-(methacryloyloxy) propyl trimethoxysilane and octadecene is 1:0.5-1:1-3 based on the total mass of the modified super-hydrophobic monomer.

3. A method for preparing the interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating according to claim 1 or 2, characterized in that: The method comprises the following steps: S1: preparing a super-hydrophobic monomer: dispersing tetra(3-mercaptopropionic acid) pentaerythritol ester, γ-(methacryloyloxy) propyl trimethoxysilane and octadecene in an organic solvent, adding a photoinitiator, and reacting under light and heating conditions, and then centrifuging and purifying with solvent to obtain a super-hydrophobic monomer; S2: modifying the super-hydrophobic monomer: hydrolyzing the super-hydrophobic monomer with tetraethyl silicate under acidic conditions to generate a modified super-hydrophobic monomer; S3: preparing a coating solution: uniformly mixing the modified super-hydrophobic monomer, polydimethylsiloxane, micron-sized silica and a curing agent to obtain a self-repairing super-hydrophobic coating solution; S4: coating and curing: coating the self-repairing super-hydrophobic coating solution on the surface of a pretreated substrate, and curing by heating in stages to form a S-MPO / PDMS self-repairing super-hydrophobic coating.

4. The method of claim 3, wherein the method comprises the steps of: (a) mixing the S-MPO and the PDMS to form a mixture; (b) coating the mixture on a substrate to form a coating layer; (c) irradiating the coating layer with UV light to form the interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating layer. The organic solvent in step S1 is tetrahydrofuran; and the photoinitiator is 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide.

5. The method of claim 3, wherein the method comprises the steps of: (a) mixing the S-MPO and the PDMS to form a mixture; (b) coating the mixture on a substrate to form a coating layer; (c) irradiating the coating layer with UV light to form the interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating layer. The reaction conditions in step S1 are UV light irradiation at 50°C for 1 hour, a centrifugation speed of 5000 r / min, a centrifugation time of 5-10 minutes, and the solvent purification uses THF with the same volume as the reaction solvent to clean three times, each time stirring for 5 minutes and then centrifuging.

6. The method of claim 3, wherein the method comprises the steps of: (a) mixing the S-MPO and the PDMS to form a mixture; (b) coating the mixture on a substrate to form a coating layer; (c) irradiating the coating layer with UV light to form the interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating layer. The acidic conditions in step S2 are adjusting the pH value to 3-5 by adding hydrochloric acid; and the mass ratio of tetraethyl silicate to super-hydrophobic monomer is 1:1.4-1.

5.

7. The method of claim 6, wherein the method comprises the steps of: (a) mixing the S-MPO and the PDMS to form a mixture; (b) coating the mixture on a substrate to form a coating layer; (c) irradiating the coating layer with UV light to form the interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating layer. The hydrolysis reaction conditions in step S2 are water bath reaction at 60°C for 8 hours, and aging for 24 hours at room temperature after reaction.

8. The method of claim 3, wherein the method comprises the steps of: (a) mixing the S-MPO and the PDMS to form a mixture; (b) coating the mixture on a substrate to form a coating layer; (c) irradiating the coating layer with UV light to form the interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating layer. The filling amount of micron-sized silica in step S3 is 6 wt%; and the mass ratio of polydimethylsiloxane to modified super-hydrophobic monomer is 1:

3.

9. The method of claim 3, wherein the method comprises the steps of: (a) mixing the S-MPO and the PDMS to form a mixture; (b) coating the mixture on a substrate to form a coating layer; (c) irradiating the coating layer with UV light to form the interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating layer. The step of uniformly mixing in step S3 comprises: ultrasonic dispersion of the tetrahydrofuran solution of modified super-hydrophobic monomer and micron-sized silica, then adding polydimethylsiloxane and magnetically stirring for 30 minutes, then adding a curing agent and continuously stirring for 3 hours, and finally ultrasonic dispersion for 10 minutes.

10. The method of claim 3, wherein the method comprises the steps of: (a) mixing the S-MPO and the PDMS to form a mixture; (b) coating the mixture on a substrate to form a coating layer; (c) irradiating the coating layer with UV light to form the interpenetrating network type S-MPO / PDMS self-healing superhydrophobic coating layer. The step S4 of the phase-wise heat curing is: pre-curing for 30 minutes at 80°C, and then fully curing for 2 hours at 120°C.

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