A silane coupling agent modified microcapsule, a functional coating, its preparation method and application

Abstract

This invention discloses a silane coupling agent modified microcapsule, a functional coating, its preparation method, and its application. The silane coupling agent modified microcapsule comprises a core material and a shell layer, with the shell layer surface grafted with a silane coupling agent. Preferably, the core material is one or more of poly-α-olefin, polyisobutylene, and alkylnaphthalene; the shell layer is one or more of nano-silica, nano-titanium dioxide, and nano-zirconia; and the silane coupling agent is one or more of KH550, KH560, and KH570. The silane coupling agent modified microcapsule exhibits good dispersion stability and interfacial compatibility, effectively solving the problems of poor dispersibility and weak interfacial bonding between traditional microcapsules and the substrate, which hinder the full realization of their functionality and reduce the overall performance of the coating due to localized stress concentration. This invention successfully prepares a silane coupling agent modified microcapsule / film-forming resin coating by combining the silane coupling agent modified microcapsule with a film-forming resin. This coating possesses both excellent anti-fouling and anti-corrosion properties.

Description

Technical Field

[0001] This invention relates to the field of functional coating materials technology, and more specifically, to a silane coupling agent modified microcapsule, a functional coating, a preparation method thereof, and its application. Background Technology

[0002] Energy loss is a common and unavoidable phenomenon in the production and conversion of various energy sources (such as tidal energy, solar energy, and wind energy), and this loss is particularly prevalent in the production and conversion of mineral ions (Ca). 2+ Mg 2+ Ba 2+ CO3 2- and SO4 2- Aqueous solutions of solvents such as aluminum (e.g., magnesium carbonate) are often used as core intermediate media for energy transfer due to their excellent heat and mass transfer properties. However, due to the thermodynamic instability and chemical compatibility limitations of aqueous solutions, scaling on equipment surfaces is difficult to avoid. The resulting precipitates such as calcium carbonate and magnesium carbonate can lead to equipment blockage, malfunctions, and substantial economic losses. Furthermore, composite metal materials widely used in engineering are prone to corrosion failure, especially in chloride-containing water environments where corrosion is accelerated, significantly shortening the service life and lifespan of equipment. Therefore, developing a scientific and effective synergistic control strategy for scale and corrosion prevention is of great significance for ensuring the safe and stable operation of energy and related industrial equipment and reducing energy consumption and economic losses.

[0003] Coating technology, with its advantages of simple construction, controllable cost, and wide applicability, has become one of the most commonly used protective solutions in the industrial field. By applying a coating with specific functions to the surface of equipment, direct contact between corrosive media and the substrate can be effectively isolated, while inhibiting the nucleation and growth of scale on the surface, thus achieving a dual protective effect against scaling and corrosion. In recent years, with the continuous development of materials science, the preparation of composite coatings by introducing functional fillers such as nanofibers, microcapsules, and nanoparticles into the coating matrix has become an important research direction for improving the overall performance of coatings. These functional fillers can endow coatings with new properties. For example, Li et al. constructed a cellulose nanofiber (CNF) / α-zirconium phosphate (α-ZrP) composite material as a nanofiller and incorporated it into water-based coatings to achieve metal corrosion protection. The resulting coating had an impedance value as high as 4.38 × 10⁻⁶. 5 Ω·cm 2This demonstrates excellent long-term corrosion protection (Reference: Li Z, Huang Y, Guo T, et al. Enhancing anticorrosion performance of metals by incorporating cellulose nanofibrils / α-ZrP composite as nanofiller into water-based coating. Carbohydrate Polymers, 2025, 347: 122755.). Zhao et al. prepared a superhydrophobic anticorrosion coating by adding fluorinated modified nano-SiO2 to polyvinylidene fluoride (PVDF). The water contact angle reached 162.6°. After immersion in 3.5wt% NaCl solution for 240 h, the low-frequency impedance modulus (|Z|) showed excellent long-term corrosion protection (Reference: Li Z, Huang Y, Guo T, et al. Enhancing anticorrosion performance of metals by incorporating cellulose nanofibrils / α-ZrP composite as nanofiller into water-based coating. Carbohydrate Polymers, 2025, 347: 122755.). 0.01 HzThe coating strength was still three orders of magnitude higher than that of the bare substrate, confirming the potential of fluorinated modified nano-SiO2 to optimize the performance of fluoropolymer coatings (Reference: Zhao YM, Zhang PY, Gu XQ, et al. Preparation of PVDF-PDMS-SiO2 multi-stage rough superhydrophobiccoating with excellent anti-corrosion and drag reduction performance via one-step cold spraying. Surface & Coatings Technology, 2023, 471: 129882.). Zhang et al. prepared microcapsules with slow-release properties using a solvent evaporation method and added them to the coating. The slow release of glycerol by the microcapsules under corrosive media significantly extended the protective life of the coating on the metal substrate (Reference: Zhang S D, Liu LK, Xu YS, et al. Research on the corrosion resistance of an epoxyresin-based self-healing propylene glycol-loaded ethyl cellulose microcapsulecoating. Coatings, 2023, 13(9):1514.). However, traditional microcapsules often suffer from poor dispersibility in coatings and weak interfacial adhesion to the substrate, which hinders their full functionality and may even reduce the overall performance of the coating due to localized stress concentration. Therefore, optimizing the dispersion stability and interfacial compatibility of microcapsules in the coating matrix through structural design and surface modification, while simultaneously endowing the coating with more efficient and durable anti-fouling and anti-corrosion properties, has become a key scientific problem that urgently needs to be solved in the field of functional coatings. Summary of the Invention

[0004] To address the problems of poor dispersibility and weak interfacial bonding between traditional microcapsules and the substrate in coatings, as well as scaling and corrosion in industrial metal equipment, this invention provides silane coupling agent modified microcapsules, functional coatings, their preparation methods, and applications.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a silane coupling agent modified microcapsule, comprising a core material and a shell layer, wherein the surface of the shell layer is grafted with a silane coupling agent. Preferably, the core material is one or more selected from polyalphaolefin (PAO), polyisobutylene (PIB), and alkylnaphthalene (AN); Preferably, the shell layer is one or more of nano-silica, nano-titanium dioxide, and nano-zirconium dioxide; Preferably, the silane coupling agent is one or more of 3-aminopropyltriethoxysilane (KH550), γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560), and acryloyloxysilane (KH570).

[0006] In some embodiments of the present invention, the silane coupling agent modified microcapsules are KH550-PAO@SiO2 microcapsules, which have PAO as the core material, SiO2 as the shell layer, and KH550 grafted onto the surface of the shell layer.

[0007] In some embodiments of the present invention, the silane coupling agent modified microcapsules are KH560-PAO@SiO2 microcapsules, which have PAO as the core material, SiO2 as the shell layer, and KH560 grafted onto the surface of the shell layer.

[0008] In some embodiments of the present invention, the silane coupling agent modified microcapsules are KH570-PAO@SiO2 microcapsules, which have PAO as the core material and SiO2 as the shell layer, with KH570 grafted onto the surface of the shell layer.

[0009] In some embodiments of the present invention, the silane coupling agent modified microcapsules are KH550-PAO@TiO2 microcapsules, which have PAO as the core material and TiO2 as the shell layer, with KH550 grafted onto the surface of the shell layer.

[0010] In some embodiments of the present invention, the silane coupling agent modified microcapsules are KH550-PAO@ZrO2 microcapsules, which have PAO as the core material, ZrO2 as the shell layer, and KH550 grafted onto the surface of the shell layer.

[0011] In some embodiments of the present invention, the silane coupling agent modified microcapsules are KH550-PIB@SiO2 microcapsules, which use PIB as the core material and SiO2 as the shell layer, with KH550 grafted onto the surface of the shell layer.

[0012] In some embodiments of the present invention, the silane coupling agent modified microcapsules are KH550-AN@SiO2 microcapsules, which use AN as the core material and SiO2 as the shell layer, with KH550 grafted onto the surface of the shell layer.

[0013] In a preferred embodiment, the mass ratio of the shell layer to the core material is 1:(1~2).

[0014] A second aspect of the present invention provides a method for preparing the above-mentioned silane coupling agent modified microcapsules, comprising the following steps: S1. Microcapsule preparation: Sa1. Dissolve 0.1~1.0g of hexadecyltrimethylammonium bromide (CTAB) in 100mL of 10wt.% ethanol solution to obtain CTAB solution; Sa2. Take 1.0~5.0g of core material raw material and add it to CTAB solution to fully emulsify it, so as to obtain core material raw material emulsion; Sa3. Add 1-2 drops of defoamer to the core material raw material emulsion, then adjust the pH to 12. Then, in an 80°C water bath, under magnetic stirring, slowly add 0.5-3.0g of shell precursor raw material. After the addition is complete, continue the reaction for 2 hours. After cooling and centrifugation, collect the precipitate. Vacuum filter the precipitate, then wash and dry it to obtain microcapsules. The shell precursor raw material is one or more of tetraethyl orthosilicate (TEOS), tetrabutyl titanate, and zirconium oxychloride (ZrOCl2·8H2O). S2. Preparation of microcapsules modified with silane coupling agents: Sb1. Disperse 0.1~1.5g of microcapsules in 40mL of 50wt.% ethanol solution to obtain microcapsule dispersion; Sb2, dissolve 0.05~0.3mL of silane coupling agent in a mixture of 20mL anhydrous ethanol and 40mL deionized water to obtain a silane coupling agent solution; Sb3. The silane coupling agent solution was added dropwise to the microcapsule dispersion and reacted in a water bath at 80°C with magnetic stirring for 6 hours. The precipitate was then collected by centrifugation, washed, and dried to obtain silane coupling agent modified microcapsules.

[0015] In the preferred embodiment, the dissolution conditions in step Sa1 are: magnetic stirring in a water bath at 50°C; In the preferred embodiment, the conditions for sufficient emulsification in step Sa2 are: high-speed homogenization dispersion at 12000 r / min for 5 min, followed by ultrasonic treatment for 15 min. In the preferred embodiment, in step Sa3, the defoamer is n-octanol, the rate of adding the shell precursor raw material is not less than 3 g / h, the centrifugation conditions are: centrifugation at 8000 r / min for 15 min, the filter membrane pore size of the vacuum filtration is 0.45 μm, the washing conditions are: washing twice with petroleum ether and twice with ultrapure water, and the drying conditions are: vacuum drying at 60℃ for 6 h.

[0016] In the preferred embodiment, the dispersion condition in step Sb1 is: ultrasonic treatment for 30 minutes.

[0017] In the preferred embodiment, in step Sb3, the centrifugation conditions are: centrifugation at 6000 r / min for 5 min, the washing conditions are: washing 3 times with anhydrous ethanol, and the drying conditions are: drying at 80℃ for 2 h.

[0018] A third aspect of the present invention provides the application of the above-described silane coupling agent modified microcapsules in the preparation of coatings with anti-fouling and / or anti-corrosion functions.

[0019] In a fourth aspect, the present invention provides a functional coating obtained by combining the above-mentioned silane coupling agent modified microcapsules with a film-forming resin.

[0020] In a preferred embodiment, the functional coating is disposed on a substrate, and a transition substrate is provided between the substrate and the functional coating; The transition substrate is one or more of the following: epoxy resin coating, polyurethane coating, acrylic resin coating, silane coupling agent primer layer, phenolic resin coating, polyamide coating, polyimide coating, phosphate conversion film, chromate passivation film, and zirconate passivation film. The substrate is made of carbon steel, stainless steel, aluminum, aluminum alloy, copper, titanium alloy, magnesium alloy, glass, ceramic, or polymer board.

[0021] In a preferred embodiment, the film-forming resin is one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (also known as perfluoroethylene propylene copolymer, FEP), perfluoroalkoxy resin (PFA), ethylene-trifluorochloroethylene copolymer (ECTFE), polychlorotrifluoroethylene (PCTFE), polyether ether ketone (PEEK), and polyphenylene sulfide (PPS).

[0022] A fifth aspect of the present invention provides a method for preparing a functional coating, comprising the following steps: 1) Substrate pretreatment: After polishing, cleaning, and drying the substrate surface, a pretreated substrate is obtained. 2) Transition substrate spraying: 2g of transition substrate material (E44) and 10g of ethyl acetate were mixed and ultrasonically dispersed for 10min to obtain a dispersion; 1g of curing agent was added to the dispersion and ultrasonically dispersed for 10min to obtain a transition substrate solution; the transition substrate solution was sprayed onto the pretreated substrate at room temperature and cured to obtain a transition substrate coating. 3) Functional coating spraying: 1g of film-forming resin was added to 10mL of anhydrous ethanol and magnetically stirred for 20min. Then, 0.1g of vapor-phase nano-SiO2 and 0.3g of the above-mentioned silane coupling agent modified microcapsules were added and ultrasonically dispersed for 40min to obtain a coating solution. The coating solution was sprayed onto the surface of the transition substrate coating and cured to obtain a functional coating.

[0023] In a preferred embodiment, the film-forming resin is a mixture of polyvinylidene fluoride and perfluoroethylene propylene copolymer; the mass ratio of polyvinylidene fluoride to perfluoroethylene propylene copolymer is 7:3.

[0024] In a sixth aspect, the present invention provides an application of the above-described functional coating.

[0025] It is understood that the embodiments of the present invention can be any one of the above solutions or a combination of two or more solutions that do not conflict with each other.

[0026] Beneficial effects of the present invention This invention uses synthetic hydrocarbon lubricating oil as the core material and inorganic oxide as the shell layer. Microcapsules are prepared via a solution-gel method, and then modified with a silane coupling agent to prepare silane coupling agent-modified microcapsules. Silane coupling agent-modified microcapsules exhibit excellent dispersion stability and interfacial compatibility, effectively solving the problems of poor dispersibility and weak interfacial bonding between traditional microcapsules and the substrate, which hinder the full realization of their functionality and may even reduce the overall performance of the coating due to localized stress concentration. By combining silane coupling agent-modified microcapsules with film-forming resins, a functional coating with both excellent anti-fouling and anti-corrosion properties was successfully prepared.

[0027] Specifically, the beneficial effects of the present invention will be further explained in detail below with reference to the KH550-PAO@SiO2 microcapsules and KH550-PAO@SiO2 / PVDF coating prepared by example of the present invention, as follows: KH550 modification effectively improves the interfacial compatibility between PAO@SiO2 microcapsules and the PVDF matrix, eliminates micropores and defects caused by nanoparticle aggregation, and improves the coating adhesion from 2B level to 5B level of SiO2 / PVDF coating, thus constructing a dense and defect-free physical barrier and laying the structural foundation for long-term protection.

[0028] Scaling experiments showed that the CaCO3 deposition rate on the surface of the KH550-PAO@SiO2 / PVDF coating was only 1.78 mg / cm³. 2 Compared to the SiO2 / PVDF coating (2.87 mg / cm³), 2 The scaling rate was reduced by approximately 37.9%. SEM, FTIR, and XRD analyses of the coating after scaling all confirmed that the KH550-PAO@SiO2 / PVDF coating inhibited the formation of thermodynamically stable and dense calcite crystals through hydrophobic interface regulation and crystal growth intervention, and induced an increase in the proportion of metastable aragonite and globule, resulting in smaller scale crystal size, crystal distortion, and weakened adhesion. This achieved efficient scale prevention through three aspects: inhibiting nucleation, preventing growth, and promoting shedding.

[0029] Electrochemical impedance spectroscopy (EIS) analysis showed that after immersion in 3.5 wt% NaCl solution for 15 days, the KH550-PAO@SiO2 / PVDF coating exhibited [significant improvement]. R p Up to 6.32×10 6 Ω·cm 2 Low-frequency impedance modulus ( It remains at 10. 8 Ω·cm 2 Compared with SiO2 / PVDF coating and PAO@SiO2 / PVDF coating, it improves by 2 to 3 orders of magnitude, demonstrating excellent long-term corrosion resistance.

[0030] The anti-corrosion mechanism of the KH550-PAO@SiO2 / PVDF coating can be summarized as the synergistic effect of dense physical barrier and enhanced interfacial chemical bonding, effectively blocking Cl... - The KH-550-PAO@SiO2 / PVDF coating bypasses the penetration pathways of corrosive media such as O2 and H2O, preventing coating failure. Through a multi-dimensional synergistic effect of "physical barrier construction, hydrophobic interface regulation, and crystal growth intervention," the coating simultaneously achieves efficient scale prevention and long-term corrosion protection. It provides a novel candidate material for metal protection under complex conditions such as oil pipelines and industrial water treatment, and also provides a theoretical basis and technical reference for the design and modification of functional composite coatings. Attached Figure Description

[0031] Figure 1 The flowchart shows the preparation process of PAO@SiO2 microcapsules (a), KH550-PAO@SiO2 microcapsules (b), and KH550-PAO@SiO2 / PVDF coating (c).

[0032] Figure 2 SEM images of PAO@SiO2 microcapsules (a, c) and KH550-PAO@SiO2 microcapsules (b, d) are shown; where (c) and (d) are magnified views of (a) and (b), respectively.

[0033] Figure 3 SEM images of three coatings are shown: (a1, a2) SiO2 / PVDF coating, (b1, b2) PAO@SiO2 / PVDF coating, and (c1, c2) KH550-PAO@SiO2 / PVDF coating; where (a2), (b2), and (c2) are magnified views of (a1), (b1), and (c1), respectively.

[0034] Figure 4 The images show the FTIR spectra of vapor-phase nano-SiO2, PAO@SiO2 microcapsules, and KH550-PAO@SiO2 microcapsules.

[0035] Figure 5 The following are the FTIR spectra of three coatings: (a) SiO2 / PVDF coating, (b) PAO@SiO2 / PVDF coating, and (c) KH550-PAO@SiO2 / PVDF coating.

[0036] Figure 6 The results show the water contact angle measurements for three coatings: (a) SiO2 / PVDF coating, (b) PAO@SiO2 / PVDF coating, and (c) KH550-PAO@SiO2 / PVDF coating.

[0037] Figure 7 The adhesion test results are for three coatings: (a) SiO2 / PVDF coating, (b) PAO@SiO2 / PVDF coating, and (c) KH550-PAO@SiO2 / PVDF coating.

[0038] Figure 8 The results of anti-scaling performance tests for three coatings are shown: (a) SiO2 / PVDF coating, (b) PAO@SiO2 / PVDF coating, and (c) KH550-PAO@SiO2 / PVDF coating.

[0039] Figure 9 SEM images of three coatings after 24 hours of scaling: (a1, a2) SiO2 / PVDF coating, (b1, b2) PAO@SiO2 / PVDF coating, and (c1, c2) KH550-PAO@SiO2 / PVDF coating.

[0040] Figure 10 The following are the FTIR spectra of three coatings after 24 hours of scaling: (a) SiO2 / PVDF coating, (b) PAO@SiO2 / PVDF coating and (c) KH550-PAO@SiO2 / PVDF coating.

[0041] Figure 11 XRD patterns of three coatings after 24 hours of scaling: (a) SiO2 / PVDF coating, (b) PAO@SiO2 / PVDF coating and (c) KH550-PAO@SiO2 / PVDF coating.

[0042] Figure 12 Schematic diagram of the scale inhibition mechanism of KH550-PAO@SiO2 / PVDF coating; (a) hydrophobic air layer inhibits scale formation, (b) KH550-PAO@SiO2 microcapsules release PAO to inhibit scale formation.

[0043] Figure 13 This is the equivalent circuit diagram.

[0044] Figure 14EIS analysis of SiO2 / PVDF coating, PAO@SiO2 / PVDF coating and KH550-PAO@SiO2 / PVDF coating after immersion in 3.5wt% NaCl solution for 3 days (a, b) and 15 days (c, d); where (a, c) are Nyquist plots and (b, d) are Bode plots. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0046] 1. Test materials and reagents Q235 steel plate (60mm×60mm×2mm), purchased from Liaocheng Yaoshun Metal Materials Co., Ltd.; polyalphaolefin (PAO, industrial grade), purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; hexadecyltrimethylammonium bromide (CTAB, analytical grade), tetraethyl orthosilicate (TEOS, analytical grade) and n-octanol (analytical grade), all purchased from Sinopharm Chemical Reagent Co., Ltd.; 3-aminopropyltriethoxysilane coupling agent (KH550, analytical grade), purchased from Dongguan Shanyi Plastics Co., Ltd.; anhydrous ethanol (analytical grade), ethyl acetate (analytical grade) and petroleum ether (60~90℃, analytical grade), purchased from Liaoning Quanrui Reagent Co., Ltd. Epoxy resin (EP, model E44) was purchased from Nantong Xingchen Synthetic Materials Co., Ltd.; epoxy resin curing agent (T-31) was purchased from Kunshan Jiuliguan Electronic Materials Co., Ltd.; polyvinylidene fluoride (PVDF, industrial grade) was purchased from Shunjie Plastics Co., Ltd.; perfluoroethylene propylene (FEP, industrial grade) was purchased from DuPont, USA; fumed silica nanoparticles (industrial grade, particle size 20nm) were purchased from Shanghai Yaoyi Alloy Materials Co., Ltd.; sodium hydroxide (analytical grade), sodium bicarbonate (analytical grade), calcium nitrate tetrahydrate (analytical grade), and sodium chloride (analytical grade) were all purchased from Sinopharm Chemical Reagent Co., Ltd.; deionized water was prepared in the laboratory.

[0047] 2. Test instruments and equipment Electronic balance (FA1204B), Shanghai Anting Electronic Instrument Factory; Sandblasting machine (9060), Guangdong Xinbaihui Automation Equipment Co., Ltd.; Ultrasonic cleaner (KQ-500VDE), Kunshan Ultrasonic Instrument Co., Ltd.; Intelligent digital display constant temperature water bath (DF-101S), Shanghai Lichen Bangxi Instrument Technology Co., Ltd.; Electric heating drying oven (101-1A), Tianjin Tester Instrument Co., Ltd.; Multi-parameter tester (Seven Excellence), Mettler Toledo Instruments (Shanghai) Co., Ltd.; Circulating water vacuum pump (SHZ-D(Ⅲ)), Gongyi Yuhua Instrument Co., Ltd.; Centrifuge (SN-LSC-2), Shanghai Shangpu Instrument Equipment Co., Ltd.; Small repair spray gun (R2-F), Shanghai Anast Iwata Coating Machinery Co., Ltd.; Scanning electron microscope (SEM, EM-30), Korea Coolsem Corporation; Fourier transform infrared spectrometer (FTIR, Tensor 27), PerkinElmer, USA; Surface tension and contact angle measuring instrument (SL200KS), Knorr Industries, USA; X-ray powder diffractometer (XRD, PW3040 / 60), Panaco, Netherlands; Electrochemical workstation (CS350H), Wuhan Koster Instruments Co., Ltd.

[0048] Example 1: KH550-PAO@SiO2 microcapsules This embodiment exemplarily provides a method for preparing KH550-PAO@SiO2 microcapsules, including the following steps: Preparation of S1 and PAO@SiO2 microcapsules: Accurately weigh 0.3 g of cetyltrimethylammonium bromide (CTAB) and add it to a three-necked flask containing 100 mL of 10 wt.% ethanol solution. Place the flask in a 50°C water bath and stir magnetically until the CTAB is completely dissolved. Then, add 3.0 g of polyalphaolefin (PAO) to the system and homogenize it at 12000 rpm for 5 min, followed by sonication for 15 min to achieve complete emulsification. Add 1-2 drops of n-octanol to eliminate foam, and adjust the pH of the system to 12 with 10 wt.% NaOH solution. Transfer the three-necked flask to an 80°C water bath and slowly add 2.0 g of tetraethyl orthosilicate (TEOS) dropwise under continuous magnetic stirring, strictly controlling the dropping rate to ensure completion within 40 min. After the addition is complete, continue the reaction for 2 h. After the reaction was completed, the reaction system was cooled to room temperature, centrifuged at 8000 r / min for 15 min to collect the precipitate, and then vacuum filtered through a 0.45 μm filter membrane. The precipitate was then washed twice each with petroleum ether and ultrapure water to remove unreacted reagents and impurities. Figure 1a) The product was finally dried in a vacuum oven at 60°C for 6 hours to obtain PAO@SiO2 microcapsules, which were then sealed and stored for later use.

[0049] Preparation of S2, KH550-PAO@SiO2 microcapsules: 0.5 g of PAO@SiO2 microcapsules were added to a three-necked flask along with 40 mL of 50 wt.% ethanol solution and sonicated for 30 min. 0.2 mL of silane coupling agent KH550 was dissolved in a mixture of 20 mL anhydrous ethanol and 40 mL deionized water. After complete dissolution, this solution was added dropwise to the three-necked flask. The mixture was magnetically stirred in an 80 °C water bath for 6 h. After the reaction was complete, the product was centrifuged at 6000 r / min for 5 min. The resulting precipitate was washed three times with anhydrous ethanol to remove unreacted KH550 from the surface. Subsequently, it was dried at 80 °C for 12 h to obtain KH550-PAO@SiO2 microcapsules, which were then sealed and stored for later use. Figure 1 b).

[0050] Example 2

[0051] In this embodiment, KH550-PAO@SiO2 / PVDF coating was exemplarily prepared using the KH550-PAO@SiO2 microcapsules prepared in Example 1 as raw material.

[0052] A method for preparing a KH550-PAO@SiO2 / PVDF coating includes the following steps: 1) Substrate pretreatment: A Q235 steel plate with dimensions of 60mm × 60mm × 2mm was selected as the experimental substrate. The substrate surface was roughened using a sandblasting process to obtain a uniformly rough surface. The sample was then placed in anhydrous ethanol and ultrasonically cleaned for 10 minutes at 40kHz and 30℃ to remove surface oil and impurities. After cleaning, the sample was removed, dried, and stored for later use.

[0053] 2) Transition substrate spraying: To improve the adhesion strength between the subsequent functional coating and the substrate, the substrate is pretreated. Epoxy resin is then sprayed onto the pretreated substrate surface as a transition substrate. The specific preparation process is as follows: Weigh 2g of epoxy resin (E44) and 10g of ethyl acetate using an electronic balance, place them in a 50mL beaker, and ultrasonically disperse them for 10min. Weigh 1g of epoxy resin curing agent (T-31) and add it to the above solution, then continue ultrasonic dispersion for 10min to obtain the transition substrate solution. Spray the uniformly dispersed transition substrate solution onto the pretreated substrate at room temperature. Place the prepared sample in a 150℃ electric heating drying oven for 0.5h to cure, thus obtaining the epoxy resin coating.

[0054] 3) Functional coating spraying: 0.7 g of polyvinylidene fluoride (PVDF) and 0.3 g of perfluoroethylene propylene copolymer (FEP) were weighed using an electronic balance, added to 10 mL of anhydrous ethanol, and magnetically stirred for 20 min. Subsequently, 0.1 g of fumed nano-SiO2 and 0.3 g of KH550-PAO@SiO2 microcapsules were added and dispersed in an ultrasonic bath for 40 min. The resulting coating solution was loaded into a spray gun and uniformly sprayed onto the epoxy resin coating surface. Finally, the sample was cured in a 180℃ electric heating oven for 1 h to obtain the KH550-PAO@SiO2 / PVDF coating.

[0055] Comparative Example 1: SiO2 / PVDF Coating In this comparative example, only 0.1g of vapor-phase nano-SiO2 was added during the SiO2 / PVDF coating process, without adding any microcapsules. The remaining processes and conditions were the same as in Example 2.

[0056] Comparative Example 2: PAO@SiO2 / PVDF Coating In this comparative example, during the preparation of the PAO@SiO2 / PVDF coating, 0.1g of PAO@SiO2 microcapsules (preparation process as in Example 1) were used instead of KH550-PAO@SiO2 microcapsules, and the remaining processes and conditions were the same as in Example 2.

[0057] Test Example 1: Characterization of Material Microstructure and Chemical Composition 1. Characterization methods 1.1 SEM characterization The microstructure of the microcapsules and coatings was observed and characterized using a scanning electron microscope (SEM, EM-30), with the testing voltage set at 10 kV. Due to the poor conductivity of the microcapsule and coating samples, all samples underwent gold sputtering before testing to improve surface conductivity, prevent charge accumulation from interfering with the microstructure observation, and ensure clear and discernible characterization images.

[0058] 1.2 FTIR Characterization The chemical composition of the microcapsules and coatings was characterized using Fourier transform infrared spectroscopy (FTIR, Tensor 27) to clarify the interactions between components and the modification effect. The test scan range was set to 4000-450 cm⁻¹. -1 The samples were prepared using the KBr pellet method to ensure uniform dispersion and guarantee the accuracy and repeatability of the infrared spectra.

[0059] 2. Characterization Results 2.1 SEM characterization results 1) SEM characterization results of microcapsules The microstructure of the PAO@SiO2 microcapsules and KH550-PAO@SiO2 microcapsules prepared in Example 1 was observed and analyzed using scanning electron microscopy (SEM). Figure 2 Image a shows a SEM image of the PAO@SiO2 microcapsules. It can be seen that the prepared PAO@SiO2 microcapsules have a relatively regular spherical structure overall, but significant inter-particle aggregation is observed, which may be related to the hydrogen bonding between hydroxyl groups on the microcapsule surface. (Partial magnification image) Figure 2 c) Further analysis shows that the PAO@SiO2 microcapsules have a wider particle size distribution, and some particles have rough surfaces. In contrast, the KH550-PAO@SiO2 microcapsules ( Figure 2 (b) The dispersion is significantly improved, interparticle aggregation is significantly reduced, and the spherical structure is more regular. (See magnified view) Figure 2 d) It can be clearly observed that the modified microcapsules have a more uniform particle size distribution and a smoother and denser surface, indicating that the modification treatment of silane coupling agent KH550 effectively improves the surface properties of the microcapsules, reduces the interaction force between particles, and thus enhances their dispersion potential in the matrix.

[0060] 2) Coating SEM characterization results To visually observe the dispersion of KH550-PAO@SiO2 microcapsules in the PVDF coating and the surface microstructure of the coating, SEM was used to observe the surfaces of the SiO2 / PVDF coating prepared in Comparative Example 1, the PAO@SiO2 / PVDF coating prepared in Comparative Example 2, and the KH550-PAO@SiO2 / PVDF coating prepared in Example 2. The results are as follows: Figure 3 As shown. SEM images of the SiO2 / PVDF coating ( Figure 3 As can be seen from a1 and a2, the coating surface is relatively smooth, but there are a few tiny bumps and pores. This is mainly due to the aggregation of vapor-phase nano-SiO2 particles in the PVDF matrix, leading to a decrease in the coating's density. (Partial magnified image) Figure 3 a2) further shows that the SiO2 particles are sparsely distributed and the interfacial bonding with the PVDF matrix is ​​not tight enough, which may provide channels for the penetration of corrosive media and scale. In contrast, the PAO@SiO2 / PVDF coating ( Figure 3 The surfaces of b1 and 3b2 showed obvious spherical protrusions, corresponding to PAO@SiO2 microcapsules. However, the microcapsules were unevenly distributed in the coating, with significant agglomeration in local areas, forming large particle clusters. This agglomeration not only disrupted the uniformity of the coating but also introduced defects within the coating, potentially leading to a decrease in its anti-fouling and anti-corrosion properties. Compared to SiO2 / PVDF coatings and PAO@SiO2 / PVDF coatings, the KH550-PAO@SiO2 / PVDF coating ( Figure 3 The surface morphology of c1 and 3c2 was significantly improved. PAO@SiO2 microcapsules were uniformly dispersed in the PVDF matrix without obvious agglomeration; spherical particles were uniformly embedded on the coating surface, forming a dense and continuous structure. (Partial magnified image) Figure 3 c2) clearly shows that the modified microcapsules have a tight interfacial bond with the PVDF matrix, effectively filling the pores inside the coating and improving the overall density of the coating. This result indicates that KH550 modification effectively improves the interfacial compatibility between the microcapsules and the PVDF matrix, enabling them to be uniformly dispersed in the coating, laying a good microstructural foundation for the coating to exhibit excellent comprehensive performance in the future.

[0061] 2.2 FTIR characterization results 1) FTIR characterization results of vapor-phase nano-SiO2 and microcapsules To further investigate the effect of silane coupling agent KH550 on the chemical structure of PAO@SiO2 microcapsules, Fourier transform infrared (FTIR) spectroscopy analysis was performed on fumed nano-SiO2, PAO@SiO2 microcapsules prepared in Example 1, and KH550-PAO@SiO2 microcapsules. The results are as follows: Figure 4 As shown. For vapor-phase nano-SiO2 ( Figure 3 a), 3460cm -1 The broader characteristic peak nearby corresponds to the stretching vibration absorption of its surface hydroxyl groups (-OH). 1630 cm⁻¹ -1 The weak absorption peak at 1075 cm⁻¹ originates from the bending vibration of hydroxyl groups (-OH) adsorbed from the water in the sample. -1 The strong and broad characteristic peak at 1398 cm⁻¹ is attributed to the asymmetric stretching vibration of the Si-O-Si bond. Furthermore, the peak at 1398 cm⁻¹... -1 807cm -1 and 470cm -1 The characteristic peaks at this location are all attributed to the vibrational modes of the Si-O bond. This is consistent with the infrared spectrum of gaseous nano-SiO2. Figure 4 a) Compared to the infrared spectrum of PAO@SiO2 microcapsules ( Figure 4 b) Seven new characteristic peaks were added, located at 2922 cm⁻¹. -1 2845cm -1 1472cm -1 1375cm -1 1224cm -1 960cm -1 and 725cm -1 At this location, all are characteristic absorption peaks of the core material PAO, directly confirming that PAO has been successfully coated inside the SiO2 shell. Specifically, at 2922 cm⁻¹... -1 2845cm -1and 1375cm -1 The absorption peaks at 1472 cm⁻¹ correspond to the asymmetric stretching vibration of the methyl group (-CH₃), the symmetric stretching vibration of the methylene group (-CH₂-), and the bending vibration of the -CH₃ group in the PAO molecule, respectively. -1 The sharp characteristic peak at 1224 cm⁻¹ is due to the absorption of the bending vibration of -CH₂-. -1 The weak absorption peak at 960 cm⁻¹ originates from the vibration of the CC backbone in the PAO molecule; -1 and 725cm -1 The characteristic peaks at the positions correspond to the out-of-plane bending vibration of the CH bond and the in-plane rocking vibration of the methylene group, respectively, further confirming the successful synthesis of PAO@SiO2 microcapsules.

[0062] Compared to PAO@SiO2 microcapsules, the infrared spectrum of KH550-PAO@SiO2 microcapsules is at 1575 cm⁻¹. -1 A new absorption peak appeared, corresponding to the bending vibration absorption of -NH2 in the KH550 molecule, indicating that KH550 has been successfully grafted onto the surface of PAO@SiO2 microcapsules. Simultaneously, characteristic absorption peaks of PAO (such as 2922 cm⁻¹) were observed. -1 2845cm -1 The PAO core material (etc.) is still clearly present in the spectrum of KH550-PAO@SiO2 microcapsules, indicating that the PAO core material inside the microcapsules did not suffer loss or chemical structural changes during the KH550 grafting process. Furthermore, the characteristic absorption peak of Si-O-Si (1075 cm⁻¹) is still clearly visible. -1 ¹、807cm -1 and 470cm -1 The presence of these features indicates that the modification by KH550 did not disrupt the basic structure of the SiO2 shell. These infrared spectral results, along with the surface morphology changes observed by SEM, corroborate each other, confirming that KH550 successfully modified the surface of the PAO@SiO2 microcapsules through a chemical reaction.

[0063] 2) FTIR characterization results of the coating To further investigate the chemical composition of the KH550-PAO@SiO2 / PVDF coating, infrared spectroscopy analysis was performed on three coatings: SiO2 / PVDF prepared in Comparative Example 1, PAO@SiO2 / PVDF prepared in Comparative Example 2, and KH550-PAO@SiO2 / PVDF prepared in Example 2. Figure 5 It can be seen that the infrared spectra of all three coatings exhibit typical characteristics of the PVDF matrix. At 3440 cm⁻¹... -1 A broad absorption peak appeared at 3020 cm⁻¹, corresponding to the stretching vibrations of residual moisture or unreacted hydroxyl groups (-OH) in the coating. -1 and 2980cm -1The characteristic peaks in the vicinity are attributed to the stretching vibrations of the CH bonds in PVDF, a typical infrared characteristic of PVDF, indicating that the matrix of all three coatings is PVDF. Furthermore, at 1630 cm⁻¹... -1 The weak absorption peak at 1400 cm⁻¹ originates from the bending vibrations of hydroxyl groups (-OH) adsorbed from water in the coating. -1 610cm -1 and 470cm -1 The absorption peak at 1185 cm⁻¹ is mainly contributed by the Si-O-Si vibration of SiO₂, and partially overlaps with the CF / CC framework vibration of PVDF. -1 The absorption peak at 838 cm⁻¹ is attributed to the asymmetric stretching vibration of the CF bond in the PVDF, while the peak at 838 cm⁻¹ is attributed to the asymmetric stretching vibration of the CF bond in the PVDF. -1 and 880cm -1 The peaks at these locations correspond to the β- and α-crystal forms of PVDF, respectively. Compared to the SiO2 / PVDF coating, the infrared spectrum of the PAO@SiO2 / PVDF coating ( Figure 5 b) A new characteristic peak is added, namely 738 cm⁻¹. -1 The peak attributable to the in-plane rocking vibration of the methylene group in the PAO molecule directly confirms that PAO has been successfully loaded into SiO2 microcapsules and introduced into the coating system. Further comparison of the spectra of PAO@SiO2 / PVDF and KH550-PAO@SiO2 / PVDF coatings reveals that the latter ( Figure 5 c) at 1575cm -1 A new absorption peak appeared, corresponding to the bending vibration of -NH2 in the KH550 molecule, indicating that KH550 has been successfully grafted onto the microcapsule surface and introduced into the coating. Simultaneously, the characteristic absorption peak of PAO (738 cm⁻¹) was observed. -1 The characteristic peaks of PVDF (3020 cm⁻¹) are still clearly visible, indicating that the KH550 modification did not affect the stability of the PAO core material in the coating. Furthermore, the characteristic peaks of PVDF (3020 cm⁻¹) are still clearly visible. -1 and 2980cm -1 No significant displacement was observed in any of the three coatings, indicating that the introduction of microcapsules and KH550 modification did not disrupt the chemical structure of the PVDF matrix, and the matrix properties of the coatings were maintained. In summary, the infrared spectral analysis results of the three coatings clearly show that the KH550-PAO@SiO2 microcapsules have been successfully introduced into the PVDF coating, and their chemical composition is consistent with the design expectations: the microcapsule surface is grafted with KH550, the interior is encapsulated with PAO core material, and the chemical structure of the PVDF matrix remains unaffected. This provides an important chemical compositional basis for the excellent anti-fouling and anti-corrosion properties of the subsequent coatings.

[0064] Test Example 2: Physical Properties of Coating 1. Measurement of water contact angle of coating The water contact angle is a key parameter characterizing the wettability of a material surface. Its value directly reflects the hydrophilicity / hydrophobicity of the coating surface and has a significant impact on the coating's anti-fouling, anti-corrosion, and other service performance characteristics. The static water contact angles of the SiO2 / PVDF coating prepared in Comparative Example 1, the PAO@SiO2 / PVDF coating prepared in Comparative Example 2, and the KH550-PAO@SiO2 / PVDF coating prepared in Example 2 were measured using a contact angle meter (model SL200KS) to evaluate the hydrophobicity of the coatings. To reduce testing errors, five different test locations were selected for parallel testing of each coating sample. The average value was taken as the final result to ensure the representativeness and reliability of the data. The water contact angle test results for the three coatings are shown below. Figure 6 As shown.

[0065] Test results show that all three coatings exhibit excellent hydrophobic properties. The water contact angle of the SiO2 / PVDF coating is 128.4°. Figure 6 a). Compared to the SiO2 / PVDF coating, the PAO@SiO2 / PVDF coating showed a slightly increased water contact angle, reaching 130.2°. Figure 6 (b) This can be attributed to the introduction of the PAO core material. As a hydrophobic organic material, PAO's uniform distribution in the coating effectively reduces the surface energy of the coating, thereby improving its hydrophobicity. Furthermore, the water contact angle of the KH550-PAO@SiO2 / PVDF coating is further increased to 132.6°. Figure 6 (c) This is mainly due to the optimization of the microcapsule surface properties by KH550. After KH550 grafting, organosilicon alkyl groups are introduced into the microcapsule surface. These groups have low surface energy, which can further enhance the hydrophobic effect of the coating surface. At the same time, the coupling effect of KH550 may improve the interfacial compatibility between the microcapsules and the PVDF matrix, making the microcapsules more uniformly dispersed in the coating, reducing surface defects caused by uneven dispersion, thereby helping to form a more complete and smooth hydrophobic surface and further improving the water contact angle. This result shows that by introducing PAO core material and surface modification with KH550, the hydrophobicity of PVDF-based coatings can be gradually improved, laying a good surface foundation for its subsequent anti-fouling and anti-corrosion performance.

[0066] 2. Mechanical stability test The interfacial bonding strength (adhesion) between the SiO2 / PVDF coating prepared in Comparative Example 1, the PAO@SiO2 / PVDF coating prepared in Comparative Example 2, and the KH550-PAO@SiO2 / PVDF coating prepared in Example 2 and the Q235 substrate was evaluated using the rating criteria in ASTM D3359 (from 0B to 5B, where 5B indicates no coating peeling and optimal adhesion). The test methods are as follows: Using a sharp blade, a 6×6 grid was drawn on the coating surface, with a grid spacing of 1mm. Then, 3M 610 tape was tightly adhered to the grid area, and pressed evenly with a clean cotton swab to ensure the tape was completely bonded to the coating surface without air bubbles. Finally, the tape was quickly peeled off perpendicular to the coating surface, and the coating removal was observed and recorded. Based on the coating removal rate, the adhesion grade was divided into 0B to 5B, with a higher grade indicating better interfacial bonding strength between the coating and the substrate. Grade 5B indicates no peeling in the gridded areas, clean and intact grid edges, and a 0% coating removal rate. Grade 0B indicates a peeling area greater than 65%, representing the worst interfacial bonding strength. The adhesion test results for the three coatings are as follows: Figure 7 As shown.

[0067] Test results show that after the SiO2 / PVDF coating is scribed, obvious coating peeling occurs at the cut edges and intersections. Figure 7 a) The affected area is greater than 5% but not greater than 15%, and according to the standard rating, it is rated 2B, indicating that its interfacial bonding strength with the metal substrate is poor. This is mainly due to the poor interfacial compatibility between the vapor-phase nano-SiO2 particles and the non-polar PVDF matrix, which easily forms defects inside the coating and weakens the bonding force between the coating and the substrate. In contrast, the PAO@SiO2 / PVDF coating ( Figure 7 The adhesion of coating b) was improved to some extent, with approximately 25% of the coating peeling off after cross-cut adhesion, resulting in an adhesion rating of 3B. The introduction of PAO@SiO2 microcapsules improved the interfacial interaction between the particles and the PVDF matrix, reduced internal defects, and thus enhanced the bonding strength between the coating and the substrate. However, due to the still weak interaction between the hydroxyl groups on the microcapsule surface and PVDF, a small amount of coating peeling still occurred. The KH550-PAO@SiO2 / PVDF coating ( Figure 7 c) It exhibits optimal adhesion; after cross-cut adhesion, the coating shows no peeling, and the grid edges are intact and smooth, earning a rating of 5B. This is because KH550, as a silane coupling agent, introduces organic functional groups onto the microcapsule surface, effectively improving the interfacial compatibility between the microcapsules and the PVDF matrix. Simultaneously, it enhances the chemical bonding between the coating and the metal substrate, forming a stronger interfacial bond and significantly improving the coating's adhesion. In summary, KH550 modification effectively optimizes the interfacial interaction between the microcapsules, the coating, and the substrate, enabling the KH550-PAO@SiO2 / PVDF coating to achieve the highest level of adhesion, providing crucial assurance for maintaining structural integrity and performance stability during long-term service.

[0068] Test Example 3: Scale Inhibition Performance of Coating To systematically evaluate the scale inhibition capabilities of different coatings and investigate the deposition patterns and adhesion characteristics of calcium carbonate crystals on the coating surface, simulated scaling experiments were conducted on the SiO2 / PVDF coating prepared in Comparative Example 1, the PAO@SiO2 / PVDF coating prepared in Comparative Example 2, and the KH550-PAO@SiO2 / PVDF coating prepared in Example 2. The scaling mass on the coating surface was monitored at different time points, and the change curve of CaCO3 deposition over time was plotted. The scale inhibition performance testing method for the coatings is as follows: The experiment was conducted using the static scaling method. (7.10 g / L) was mixed with NaHCO3 (5.04 g / L) solution and reacted at 60 °C to generate a supersaturated CaCO3 solution (reaction formula (1)). Subsequently, the coated sample was vertically immersed in the above solution and allowed to stand in a constant temperature environment (60 °C). The samples were taken out at preset time points, rinsed with deionized water, dried in a vacuum drying oven, and then weighed using an analytical balance with an accuracy of 0.01 mg. By calculating the amount of scale deposited per unit area, the scaling rate of different coatings at different time periods was analyzed, and their scale inhibition performance was compared.

[0069] +2NaHCO3→ CaCO3↓+2NaNO3+5H2O+CO2↑ (1) Figure 8 The graphs show the changes in CaCO3 deposition after applying SiO2 / PVDF coating, PAO@SiO2 / PVDF coating, and KH550-PAO@SiO2 / PVDF coating structures. Figure 8 Analysis showed that the CaCO3 deposition on the surfaces of all three coatings gradually increased over time, but the growth rate and final deposition amount differed significantly. In the first stage (0–6 h), the CaCO3 deposition amounts on the surfaces of the SiO2 / PVDF, PAO@SiO2 / PVDF, and KH550-PAO@SiO2 / PVDF coatings were 0.708 mg / cm³, respectively. 2 0.496 mg / cm 2 and 0.256 mg / cm 2 This stage mainly corresponds to the rapid nucleation and initial adhesion of CaCO3 crystals on the coating surface. The deposition amount on the KH550-PAO@SiO2 / PVDF coating surface is only about 36.1% of that on the SiO2 / PVDF coating, indicating its significant advantage in suppressing crystal nucleation. As time progresses to the second stage (6~168h), the scaling rate of all three coatings increases, but the differences further widen. The SiO2 / PVDF coating ( Figure 8 a) The deposition rate increased rapidly, reaching 2.76 mg / cm³ at 168 h. 2The PAO@SiO2 / PVDF coating ( Figure 8 b) and KH550-PAO@SiO2 / PVDF coating ( Figure 8 c) The deposition amount was 2.29 mg / cm³. 2 and 1.73 mg / cm 2 This stage primarily involves crystal growth and aggregation. The dense, hydrophobic structure of the KH550-PAO@SiO2 / PVDF coating effectively hinders the continuous deposition of CaCO3. Entering the third stage (168–240 h), the deposition rates of all three coatings tend to plateau. The SiO2 / PVDF coating achieves the highest final deposition amount, at 2.87 mg / cm³. 2 The PAO@SiO2 / PVDF coating concentration is 2.49 mg / cm³. 2 The deposition rate of the KH550-PAO@SiO2 / PVDF coating was only 1.78 mg / cm³. 2 This coating exhibits significantly lower anti-fouling performance than the previous two types. This difference in anti-fouling performance can be attributed to the following mechanism: Firstly, the SiO2 / PVDF coating has a strong hydrophilic surface and contains many defects, which provides a large number of favorable sites for the nucleation, growth and adhesion of CaCO3 crystals, thus resulting in the worst anti-scaling performance.

[0070] Secondly, the introduction of PAO core material improves the hydrophobicity of PAO@SiO2 / PVDF coating, which to some extent inhibits crystal nucleation and adhesion. However, the aggregation of PAO@SiO2 microcapsules in the coating still results in many defects on the surface, and the anti-scaling effect needs to be further improved.

[0071] Thirdly, the KH550 modification brings dual advantages. On the one hand, the organosilicon groups grafted onto the surface of the PAO@SiO2 microcapsules further enhance the hydrophobicity of the KH550-PAO@SiO2 / PVDF coating, effectively inhibiting the nucleation and growth of CaCO3 crystals. On the other hand, KH550 improves the interfacial compatibility between the microcapsules and the PVDF matrix, resulting in more uniform dispersion of the KH550-PAO@SiO2 microcapsules in the coating, forming a denser coating structure, reducing the sites for CaCO3 deposition, and thus exhibiting optimal anti-scaling performance. Therefore, the KH550-PAO@SiO2 / PVDF coating significantly inhibits CaCO3 deposition on the coating surface by synergistically improving hydrophobicity and coating density, providing an important guarantee for its application in industrial water treatment and other fields.

[0072] The following sections will characterize the SiO2 / PVDF coating, PAO@SiO2 / PVDF coating, and KH550-PAO@SiO2 / PVDF coating after 24 hours of scaling.

[0073] 1. Microscopic morphology analysis of CaCO3 crystals on the coating surface after scaling To further reveal the regulatory mechanism of different coatings on CaCO3 scaling behavior, SEM (same as in Test Example 1) was used to characterize the CaCO3 crystal morphology, distribution state, and adhesion characteristics on the surfaces of three coatings—SiO2 / PVDF, PAO@SiO2 / PVDF, and KH550-PAO@SiO2 / PVDF—after 24 hours of scaling. The results are as follows: Figure 9 As shown.

[0074] From low-magnification SEM images ( Figure 9 (a1, 9b1, 9c1) It can be clearly observed that the coverage density of CaCO3 crystals on the three coating surfaces shows significant differences. The SiO2 / PVDF coating surface is densely covered by a large number of CaCO3 crystals, which agglomerate to form a continuous scale layer, almost completely obscuring the coating surface. Only in local areas can the coating outline be observed. Figure 9 a1). The crystal coverage density on the surface of the PAO@SiO2 / PVDF coating is significantly reduced, with crystals distributed in dispersed clusters, failing to form a continuous scale layer, and the exposed area of ​​the coating is significantly increased. Figure 9 b1). The number of CaCO3 crystals on the surface of the KH550-PAO@SiO2 / PVDF coating is extremely small, with only sporadic crystal aggregates present, and the vast majority of the coating surface remains clean. Figure 9 c1), scaling is greatly suppressed.

[0075] High magnification SEM images ( Figure 9 (a2, 9b2, 9c2) further revealed the microstructure and growth characteristics of CaCO3 crystals. On the surface of the SiO2 / PVDF coating ( Figure 9 a2), CaCO3 crystals mainly exist in a regular calcite-type hexagonal prismatic morphology, with uniform crystal size (approximately 5~10 μm), complete crystal form, and distinct edges. The crystals are tightly stacked and interlocked, forming a dense and strongly adherent scale layer. This phenomenon indicates that the hydrophilic defects on the SiO2 / PVDF coating surface provide ideal nucleation sites for the directional growth and dense stacking of CaCO3 crystals, resulting in mature crystal growth and strong adhesion. CaCO3 crystals on the PAO@SiO2 / PVDF coating surface ( Figure 9(b2) The morphology undergoes significant changes. The proportion of calcite-type crystals decreases, the crystal size is significantly reduced (approximately 2–5 μm), the crystal integrity declines, the edges become blurred, and some crystals exhibit irregular flocculent or agglomerated structures. Simultaneously, the stacking density between crystals decreases, noticeable gaps appear, and the compactness of the scale layer is greatly weakened. This is mainly attributed to the hydrophobicity imparted to the coating by the PAO core material, which to some extent interferes with the growth kinetics of CaCO3 crystals, inhibiting crystal growth and dense stacking. However, the surface defects formed by the aggregation of PAO@SiO2 microcapsules still provide conditions for the growth of some crystals.

[0076] Compared to SiO2 / PVDF coatings and PAO@SiO2 / PVDF coatings, the CaCO3 crystals on the surface of the KH550-PAO@SiO2 / PVDF coating ( Figure 9 c2) exhibited the most significant morphological anomalies and growth inhibition characteristics. A small number of crystals existed as isolated aggregates, and some crystals showed severe distortion, with the calcite-type hexagonal prismatic structure almost disappearing. Furthermore, the contact area between the crystals and the coating surface was extremely small, indicating very weak adhesion between the crystals and the coating surface, making them prone to detachment under external forces. Therefore, the chemical properties and microstructure of the coating surface directly regulate the nucleation density, growth mode, and morphological characteristics of CaCO3 crystals. The KH550-PAO@SiO2 / PVDF coating not only significantly reduced the crystal nucleation density but also disrupted the normal crystal growth process, leading to the formation of deformed crystals with incomplete crystal forms and weak adhesion. This morphological characteristic is related to the scale quality data of the coating surface (…). Figure 8 The results are highly consistent, further confirming the synergistic effect of KH550 modified PAO@SiO2 microcapsules on the anti-scaling performance of the coating from the perspective of the microscopic mechanism of crystal growth.

[0077] 2. Infrared spectral analysis of CaCO3 crystals on the coating surface after scaling. To further verify the presence and crystal structure characteristics of CaCO3 crystals on the coating surface, FTIR analysis was performed on three coatings—SiO2 / PVDF, PAO@SiO2 / PVDF, and KH550-PAO@SiO2 / PVDF—after 24 hours of scaling (same as in Test Example 1). The results are as follows: Figure 10 As shown.

[0078] Infrared spectrum of unscaled coating ( Figure 5 Compared to the previous three coatings, the three coatings retained 2980cm after scaling. -1 The peak at 1575 cm⁻¹ is attributed to the stretching vibration of the CH bond in PVDF. -1 The peak corresponds to the bending vibration of -NH2 in the KH550 molecule, at 738 cm⁻¹. -1The peak at 610 cm⁻¹ is attributed to the in-plane rocking vibration of the methylene group in the PAO molecule. -1 and 470cm -1 In addition to the Si-O-Si vibrational peak originating from SiO2, there is also a peak at 2510 cm⁻¹. -1 1420cm -1 875cm -1 and 712cm -1 New characteristic absorption peaks appeared at all locations. Among them, the peak at 2510 cm⁻¹ was the highest. -1 The absorption peak at 1420 cm⁻¹ corresponds to the stretching vibration of C=O in CaCO₃; -1 875cm -1 and 712cm -1 The absorption peaks at 875 cm⁻¹ correspond to the antisymmetric stretching vibration, in-plane bending vibration, and out-of-plane vibration of CO in CaCO₃, respectively, indicating that CaCO₃ crystals are formed on the surface of all three coatings. Notably, compared to the SiO₂ / PVDF and PAO@SiO₂ / PVDF coatings, the KH550-PAO@SiO₂ / PVDF coating exhibits a higher absorption peak at 875 cm⁻¹. -1 and 712cm -1 The characteristic peak intensity at the point was significantly reduced. This result indicates that the PAO@SiO2 microcapsules modified by KH550 not only significantly reduced the deposition of CaCO3 crystals on the coating surface, but may also have a significant impact on the growth and crystallization state of the crystals.

[0079] Further comparison of peak intensities reveals that the SiO2 / PVDF coating ( Figure 10 a) exhibits the strongest CaCO3 characteristic peak intensity, indicating the most severe scaling on its surface. PAO@SiO2 / PVDF coating ( Figure 10 The peak intensity of (b) decreased, reflecting a reduction in scaling. Meanwhile, the KH550-PAO@SiO2 / PVDF coating ( Figure 10 c) has the weakest peak intensity, indicating that it has the least amount of CaCO3 deposition on its surface and the best anti-scaling performance. This trend is consistent with the aforementioned changes in the quality of scaling on the coating surface ( Figure 5 ) and SEM morphology analysis ( Figure 9 The conclusions are completely consistent, further verifying the synergistic effect of KH550 modification on the anti-scaling performance of the coating from the perspective of chemical composition. Therefore, FTIR analysis of the scaled coating confirmed the presence of CaCO3 crystals, and the changes in peak intensity quantitatively reflected the differences in anti-scaling performance. Combined with scale quality testing and SEM analysis, these results constitute a comprehensive evidence system, providing strong support for elucidating the mechanism by which KH550 modification enhances the anti-scaling performance of the KH550-PAO@SiO2 / PVDF coating.

[0080] 3. XRD analysis of CaCO3 crystals on the coating surface after scaling To further investigate the effect of KH550 modification on the CaCO3 crystal structure of the coating surface, XRD analysis was performed on the CaCO3 deposits on the surfaces of SiO2 / PVDF, PAO@SiO2 / PVDF, and KH550-PAO@SiO2 / PVDF coatings 24 hours after scaling. Phase analysis of the CaCO3 crystals deposited on the coating surface was performed using an X-ray diffractometer (PW3040 / 60) to clarify the phase composition and crystallization characteristics of the scale crystals. The test used Cu target Kα rays (λ=0.15406nm), with the diffraction angle range set to 10°~80° and the scan rate controlled at 5° / min. Parameters were kept stable during the test to ensure reliable diffraction data. The XRD patterns of the three coatings after scaling are shown below. Figure 11 As shown.

[0081] Depend on Figure 11 Analysis revealed that characteristic diffraction peaks of calcite, aragonite, and aragonite were detected in the CaCO3 deposits on the surfaces of the three coatings, confirming that the scaling products were a polymorphic mixed system. However, the intensity and relative proportion of the diffraction peaks of each crystal type differed significantly. Specifically, the characteristic diffraction peaks of calcite corresponded to the 2θ=29.1° (104) and 47.1° (024) crystal planes, the characteristic diffraction peaks of aragonite were located on the 2θ=38.1° (130) and 48.2° (041) crystal planes, and the characteristic diffraction peaks of aragonite appeared on the 2θ=42.7° (008) crystal plane. From the intensity of the diffraction peaks, the SiO2 / PVDF coating ( Figure 11 a) exhibits the highest intensity calcite characteristic peak (29.1°), representing the dominant crystal form in the system. Simultaneously, the diffraction peaks of aragonite and aragonite are clearly distinguishable, indicating that the coating surface more readily induces the formation of a large amount of thermodynamically stable calcite. Figure 9 The observed intact calcite crystals exhibited highly consistent morphology. PAO@SiO2 / PVDF coating ( Figure 11 b) The intensity of the calcite characteristic peaks decreased slightly, while the aragonite diffraction peaks were relatively enhanced, reflecting that the introduction of PAO core material initially changed the crystal growth orientation of CaCO3, leading to an increase in the proportion of metastable crystal forms.

[0082] In stark contrast, the KH550-PAO@SiO2 / PVDF coating ( Figure 11c) The intensity of the calcite characteristic peaks was significantly weakened, while the diffraction peaks of aragonite and globule became the main characteristic peaks, and the overall diffraction peaks were significantly broadened and the crystallinity decreased. This phenomenon indicates that KH550 modification, by optimizing the hydrophobic properties and interfacial compatibility of the KH550-PAO@SiO2 / PVDF coating surface, not only inhibited the directional growth of calcite but also significantly promoted the formation of metastable globule and globule. Since globule and globule have loose crystal structures and weak adhesion, they are more likely to detach from the coating surface, which may be one of the important reasons why the KH550-PAO@SiO2 / PVDF coating has superior anti-scaling performance. Therefore, the XRD analysis results of the coating after scaling further confirm the regulatory effect of KH550-modified PAO@SiO2 microcapsules on the growth of CaCO3 crystals from the perspective of crystal phase composition, consistent with the previous SEM morphology analysis (…). Figure 9 FTIR chemical characterization Figure 10 ) and scale quality test results ( Figure 8 This forms a complete chain of evidence, providing key physical evidence for systematically elucidating the anti-scaling mechanism of the KH550-PAO@SiO2 / PVDF coating.

[0083] Analysis of the anti-scaling mechanism of the coating: Based on the above adhesion test, scaling behavior monitoring, microstructure characterization, and phase analysis results, the excellent anti-scaling performance of the KH550-PAO@SiO2 / PVDF coating stems from the synergistic effect of interface compatibility optimization, surface hydrophobicity regulation, and crystal growth behavior intervention. Its anti-scaling mechanism can be summarized in the following three aspects: First, KH550 modification achieved interfacial synergy between the nanofiller and the PVDF matrix, constructing a dense, defect-free physical barrier in the coating. The silane coupling agent KH550, through chemical bonding, binds to the hydroxyl groups on the surface of PAO@SiO2 microcapsules at one end and forms intermolecular interactions with the PVDF matrix at the other, effectively solving the problem of poor compatibility between the original SiO2 particles and the PVDF matrix. This modification ensures uniform dispersion of the microcapsules in the coating, eliminating defects such as micropores and cracks caused by agglomeration. Figure 6 This reduces the physical sites for heterogeneous nucleation of CaCO3 crystals, laying the foundation for scale prevention at the structural level.

[0084] Secondly, the gradient increase in hydrophobicity of the coating surface significantly inhibits the adsorption of water molecules and the initial adhesion of crystals. The introduction of the PAO core material lays the foundation for the hydrophobicity of the coating, while the organosilicon alkyl groups grafted with KH550 further reduce the surface energy of the coating, thereby forming a strongly hydrophobic interface rich in air films. This hydrophobic property makes it difficult for a continuous and stable water film to form on the coating surface, hindering the initial adsorption and growth of CaCO3 crystal nuclei. Figure 7Scale quality data shows that the CaCO3 deposition rate of this coating within 0-6 hours is only 36.1% of that of the SiO2 / PVDF coating. Figure 12 a). At the same time, the hydrophobic interface weakens the van der Waals forces and hydrogen bonds between the crystal and the coating, making it difficult for the primary crystal nuclei to adhere firmly, thus creating conditions for subsequent crystal detachment.

[0085] Finally, the KH550-PAO@SiO2 / PVDF coating can directionally regulate the crystal growth and crystallization behavior of CaCO3, reducing the adhesion and stability of the scale layer. Figure 12 b). After the PAO core material in the KH550-PAO@SiO2 / PVDF coating is slowly released from the microcapsules, a dynamic lubrication layer is formed on the coating surface. This lubrication layer physically adsorbs onto the surface of the CaCO3 crystals through weak intermolecular interactions, interfering with the orderly arrangement of crystal growth and causing the CaCO3 crystals, which originally tend to form dense calcite, to transform into aragonite or spherulite with lower thermodynamic stability. Figure 11 This crystal transformation results in a loose scale structure and severe crystal distortion. Furthermore, the reduced crystallinity and increased lattice defects make it highly susceptible to detachment under fluid shear forces. This "suppression of stability and promotion of metastability" crystal structure regulation effect fundamentally disrupts the formation and solidification process of the scale layer, which is the core mechanism for the coating's efficient scale prevention. Therefore, the KH550-PAO@SiO2 / PVDF coating, through the triple synergistic effect of physical barrier construction, hydrophobic interface regulation, and crystal growth intervention, inhibits the formation of CaCO3 scale layers from three key aspects: "anti-adhesion, growth inhibition, and detachment promotion," ultimately achieving excellent and stable scale prevention performance. This mechanism provides important theoretical basis and technical reference for the design and modification of functional scale-preventing coatings.

[0086] Test Example 4: Corrosion Resistance of Coating The corrosion resistance of the coated samples was systematically tested using a Parstat 3000A electrochemical workstation. A 3.5wt% NaCl solution was selected as the test medium to simulate the actual industrial corrosion environment, ensuring the practicality and reliability of the test results. The test employed a classic three-electrode system, with the specific settings as follows: The working electrode is a Q235 metal substrate coated with different types of coatings. The substrate undergoes strict encapsulation before testing, with only 1 cm exposed. 2The coating surface was used as the effective test area to avoid interference from non-test areas. A platinum sheet was used as the auxiliary electrode, and a saturated calomel electrode (SCE) was used as the reference electrode. The testing process was conducted in two orderly steps: First, open-circuit potential (OCP) testing was performed, continuously monitoring the potential change trend of the working electrode in a 3.5 wt% NaCl solution for 1 hour. The potential fluctuations were used to assess the initial service stability of the coating in the corrosive medium and to determine whether the coating had experienced initial damage or failure. Then, electrochemical impedance spectroscopy (EIS) testing was performed, with the test frequency range set at 10 Hz. 5 Hz to 10 -2 The applied AC signal amplitude was 5mV (relative to the system open-circuit potential) at Hz to avoid damage to the coating structure due to excessive signal strength. After the test, the characteristic changes of the Nyquist and Bode plots were analyzed, and equivalent circuit fitting was performed using ZSimpWin software to extract the coating charge transfer resistance. R ct ), coating resistor ( R c Parameters such as ) are used to characterize the barrier properties and interfacial corrosion behavior of the coating.

[0087] To comprehensively evaluate the practical application value of the KH550-PAO@SiO2 / PVDF coating, its corrosion resistance is equally crucial, in addition to its excellent anti-scaling properties. The corrosion resistance of different coatings in a 3.5 wt% sodium chloride solution was investigated using electrochemical impedance spectroscopy (EIS), and the corrosion resistance was determined based on the equivalent circuit (…). Figure 13 The EIS data were fitted to obtain the key electrochemical parameters (Table 1). Among them, R s and R p These represent solution resistance and polarization resistance, respectively. CPE This refers to the coating capacitance that reflects the diffusion process of the electrolyte solution. Typically, R p The bigger, R s The smaller the value, the stronger the ion barrier ability of the coating, and the better its corrosion resistance.

[0088] Figure 14 The EIS results of the SiO2 / PVDF coating prepared in Comparative Example 1, the PAO@SiO2 / PVDF coating prepared in Comparative Example 2, and the KH550-PAO@SiO2 / PVDF coating prepared in Example 2 after immersion in 3.5 wt% sodium chloride solution for 3 days and 15 days are shown. From the Nyquist plot ( Figure 14(a) and (c) show that all three coatings exhibit typical capacitive arc resistance characteristics. When immersed in a 3.5 wt% sodium chloride solution for 3 days, the capacitive arc diameter of the KH550-PAO@SiO2 / PVDF coating is significantly larger than that of the SiO2 / PVDF and PAO@SiO2 / PVDF coatings, indicating that it exhibits stronger corrosive media barrier capabilities in the initial immersion stage. As the immersion time is extended to 15 days, the capacitive arc diameter of all three coatings decreases. This is due to the corrosive media (such as Cl...) - As the corrosion gradually penetrates into the coating, the barrier effect of the coating is weakened to some extent. However, the capacitive arc diameter of the KH550-PAO@SiO2 / PVDF coating remains the largest, much higher than that of the SiO2 / PVDF coating and the PAO@SiO2 / PVDF coating, indicating that its long-term corrosion resistance still has a significant advantage.

[0089] Bode diagram ( Figure 14 b) and d) further quantified the corrosion resistance of the coating, including the impedance modulus |Z| in the low-frequency region (0.01Hz). 0.01Hz |Z| is a core indicator for evaluating the long-term protective performance of coatings; the higher the value, the stronger the coating's ability to block corrosive media. After immersion in a 3.5 wt% sodium chloride solution for 3 days, the |Z| values ​​of the SiO2 / PVDF coating, PAO@SiO2 / PVDF coating, and KH550-PAO@SiO2 / PVDF coating were compared. 0.01Hz Approximately 10 respectively 6 Ω·cm 2 10 7 Ω·cm 2 and 10 9 Ω·cm 2 The low-frequency impedance modulus of the KH550-PAO@SiO2 / PVDF coating is 2-3 orders of magnitude higher than that of the other three coatings. After immersion for 15 days, the |Z| of the KH550-PAO@SiO2 / PVDF coating... 0.01Hz It remains at 10 8 Ω·cm 2 Compared to SiO2 / PVDF coatings (10 5 Ω·cm 2 Three orders of magnitude higher than PAO@SiO2 / PVDF coatings (10 6 Ω·cm 2 The difference is two orders of magnitude higher, which fully demonstrates that the coating has excellent long-term corrosion resistance.

[0090] Table 1. EIS fitting data of different coatings after immersion in 3.5wt% NaCl solution for 15 days. <![CDATA[SiO2 / PVDF]]> <![CDATA[4.71×10 3 ]]> <![CDATA[7.86×10 -7 ]]> <![CDATA[1.04×10 6 ]]> <![CDATA[PAO@SiO2 / PVDF]]> <![CDATA[1.54×10 3 ]]> <![CDATA[3.61×10 -9 ]]> <![CDATA[1.49×10 6 ]]> <![CDATA[KH550-PAO@SiO2 / PVDF]]> <![CDATA[2.14×10 3 ]]> <![CDATA[1.41×10 -9 ]]> <![CDATA[6.32×10 6 ]]> Analysis of the anti-corrosion mechanism of the coating: Combining the EIS data fitting results in Table 1, the underlying reasons for the differences in corrosion resistance of different coatings can be further clarified. SiO2 / PVDF coatings... R p Only 1.04×10 6 Ω·cm 2 , CPE The value is as high as 7.86×10 -7 μF·cm -2 Its weak corrosion resistance mainly stems from the poor interfacial compatibility between nano-SiO2 particles and the PVDF matrix, resulting in numerous micropores and microcracks within the coating. These defects become the source of corrosion. - The rapid penetration of corrosive media such as H2O significantly weakens the physical barrier effect of the coating, ultimately leading to poor corrosion resistance. The PAO@SiO2 / PVDF coating... R p Increased to 1.49×10 6 Ω·cm 2 , CPE The value decreased significantly to 3.61 × 10⁻⁶. -9 μF·cm -2 This indicates that the introduction of PAO core material can fill some internal defects in the coating, improve coating density, and enhance the ion barrier ability and corrosion resistance of the coating to a certain extent. However, PAO@SiO2 microcapsules are prone to aggregation in the coating, which can still form local weak areas, limiting further improvement in its protective performance. However, the KH550-PAO@SiO2 / PVDF coating... R p Up to 6.32×10 6 Ω·cm 2 , CPE The value further decreased to 1.41 × 10 -9 μF·cm -2 Its excellent anti-corrosion performance is mainly attributed to the surface modification effect of KH550. On the one hand, KH550 modification effectively solves the interfacial compatibility problem between PAO@SiO2 microcapsules and the PVDF matrix, enabling the microcapsules to be uniformly dispersed in the PVDF matrix, filling the micropores and microcracks inside the coating, and constructing a continuous and dense physical barrier, thus blocking Cl from the source. -The KH550 coating prevents corrosive media such as O2 and H2O from penetrating into the metal substrate, thus avoiding corrosion reactions. Furthermore, the KH550 molecules form stable chemical bonds with both ends of the PAO@SiO2 microcapsules and the metal substrate, enhancing the bonding force between the microcapsules and the PVDF matrix, and significantly improving the interfacial adhesion between the coating and the metal substrate. This effectively prevents blistering, cracking, and peeling during long-term immersion, ensuring the integrity and long-term effectiveness of the coating's protective structure. Therefore, the KH550-PAO@SiO2 / PVDF coating, through interfacial modification and structural optimization, achieves efficient and long-term corrosion protection for metal substrates. Combined with its excellent anti-scaling properties, this coating can meet the needs of complex corrosion and scaling coupled conditions in oil pipelines, industrial water treatment equipment, and other applications, providing an ideal new candidate material for industrial metal protection.

[0091] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A silane coupling agent modified microcapsule, comprising a core material and a shell, characterized in that, The shell surface is grafted with a silane coupling agent; The core material is one or more of polyα-olefin, polyisobutylene, and alkylnaphthalene; The shell is one or more of nano-silica, nano-titanium dioxide, and nano-zirconium dioxide; The silane coupling agent is one or more of 3-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and acryloyloxysilanes.

2. A method for preparing the silane coupling agent modified microcapsules according to claim 1, characterized in that, Includes the following steps: S1. Microcapsule preparation: Sa1. Dissolve 0.1~1.0g of hexadecyltrimethylammonium bromide in 100mL of 10wt.% ethanol solution to obtain hexadecyltrimethylammonium bromide solution; Sa2. Take 1.0~5.0g of core material raw material and add it to a hexadecyltrimethylammonium bromide solution and emulsify it thoroughly to obtain the core material emulsion raw material solution; Sa3. Add 1-2 drops of defoamer to the core material raw material emulsion, then adjust the pH value to 12. Then, in an 80°C water bath, under magnetic stirring, slowly add 0.5-3.0g of shell precursor raw material. After the addition is complete, continue the reaction for 2 hours, then collect the precipitate after cooling and centrifugation. The precipitate was vacuum filtered, then washed and dried to obtain microcapsules; the shell precursor raw material was one or more of tetraethyl orthosilicate, tetrabutyl titanate, and zirconium oxychloride. S2. Preparation of microcapsules modified with silane coupling agents: Sb1. Disperse 0.1~1.5g of microcapsules in 40mL of 50wt.% ethanol solution to obtain microcapsule dispersion; Sb2, dissolve 0.05~0.3mL of silane coupling agent in a mixture of 20mL anhydrous ethanol and 40mL deionized water to obtain a silane coupling agent solution; Sb3. The silane coupling agent solution was added dropwise to the microcapsule dispersion and reacted in a water bath at 80°C with magnetic stirring for 6 hours. The precipitate was then collected by centrifugation, washed, and dried to obtain silane coupling agent microcapsules.

3. The method for preparing silane coupling agent modified microcapsules according to claim 2, characterized in that, In step Sa1, the dissolution conditions are: magnetic stirring in a water bath at 50°C; in step Sa2, the conditions for complete emulsification are: high-speed homogenization dispersion at 12000 r / min for 5 min, followed by ultrasonic treatment for 15 min; in step Sa3, the defoamer is n-octanol, the rate of adding the shell precursor raw material is not less than 3 g / h, the centrifugation conditions are: centrifugation at 8000 r / min for 15 min, the pore size of the filter membrane for vacuum filtration is 0.45 μm, the washing conditions are: washing twice each with petroleum ether and ultrapure water, and the drying conditions are: vacuum drying at 60°C for 6 h.

4. The method for preparing silane coupling agent modified microcapsules according to claim 2, characterized in that, In step Sb1, the dispersion conditions are: ultrasonic treatment for 30 min; in step Sb3, the centrifugation conditions are: centrifugation at 6000 r / min for 5 min, the washing conditions are: washing 3 times with anhydrous ethanol, and the drying conditions are: drying at 80℃ for 2 h.

5. The use of the silane coupling agent modified microcapsules of claim 1 in the preparation of coatings with anti-fouling and / or anti-corrosion functions.

6. A functional coating, characterized in that, It is obtained by combining the silane coupling agent modified microcapsules as described in claim 1 with a film-forming resin.

7. The functional coating according to claim 6, characterized in that, The functional coating is disposed on the substrate, and a transition substrate is provided between the substrate and the functional coating; The transition substrate is one or more of the following: epoxy resin coating, polyurethane coating, acrylic resin coating, silane coupling agent primer layer, phenolic resin coating, polyamide coating, polyimide coating, phosphate conversion film, chromate passivation film, and zirconate passivation film. The substrate is made of carbon steel, stainless steel, aluminum, aluminum alloy, copper, titanium alloy, magnesium alloy, glass, ceramic, or polymer board.

8. The functional coating according to claim 6, characterized in that, The film-forming resin is one or more of polyvinylidene fluoride, polytetrafluoroethylene, fluorinated ethylene propylene copolymer, perfluoroalkoxy resin, ethylene-trifluorochloroethylene copolymer, polychlorotrifluoroethylene, polyether ether ketone, and polyphenylene sulfide.

9. A method for preparing the functional coating according to any one of claims 6 to 8, characterized in that, Includes the following steps: 1) Substrate pretreatment: After polishing, cleaning, and drying the substrate surface, a pretreated substrate is obtained. 2) Transition substrate spraying: 2g of transition substrate material and 10g of ethyl acetate were mixed and ultrasonically dispersed for 10min to obtain a dispersion; 1g of curing agent was added to the dispersion and ultrasonically dispersed for 10min to obtain a transition substrate solution; the transition substrate solution was sprayed onto the pretreated substrate at room temperature and cured to obtain a transition substrate coating. 3) Functional coating spraying: 1g of film-forming resin was added to 10mL of anhydrous ethanol and magnetically stirred for 20min. Then, 0.1g of fumed nano-SiO2 and 0.3g of the silane coupling agent modified microcapsules according to claim 1 were added and ultrasonically dispersed for 40min to obtain the coating solution. The coating solution is sprayed onto the surface of the transition substrate coating, and after curing, a functional coating is obtained.

10. The application of the functional coating according to any one of claims 5 to 8.

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