Nano island-shaped multifunctional temporary anti-fouling composite coating and preparation method thereof

Abstract

The invention discloses a preparation method of a nano island-shaped multifunctional temporary anti-fouling composite coating. The method comprises the following steps: (1) mixing and stirring a PDMS main agent and a curing agent, and uniformly brushing a glass slide with the mixture; step (2), preparing SiO2 powder; step (3), preparing amorphous BSO powder; (4) preparing TB composite powder; (5) preparing TBC composite powder; (6), SiO2 and TBC composite powder are dispersed in absolute ethyl alcohol, and a G solution and an H solution can be obtained; and step (7), carrying out ultrasonic dispersion on the obtained G liquid and H liquid, and then spraying onto a PDMS matrix one by one by adopting a spraying method, so as to obtain the PDMS-SiO2-TBC composite coating material. The method has the characteristics of low cost, easiness in operation, no toxicity, no harm and short production period, and can improve the anti-pollution performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of anti - fouling coatings, and particularly relates to a nano - island - shaped multifunctional temporary anti - fouling composite coating and a preparation method thereof. Background Art

[0002] Traditional temporary anti - fouling coatings are highly toxic and prone to cause secondary pollution to the ecosystem. As one of the representatives of typical silane materials, polydimethylsiloxane (PDMS) has been widely used in the research of temporary protective coatings due to its low surface energy, non - toxicity, harmlessness, and environmental friendliness. However, its own protective performance is weak, and it is difficult to achieve multifunctional and highly efficient anti - fouling such as liquid pollutant isolation and harmful microorganism protection.

[0003] To improve the anti - fouling performance of PDMS, based on the design idea of multi - component collaborative green anti - fouling, a composite coating can be prepared by combining it with a photocatalytic material using a suitable production process. Titanium dioxide (TiO2) is a common inorganic photocatalytic material, but its wide bandgap, poor light utilization rate, and difficult separation of carriers lead to its photocatalytic performance not meeting the usage requirements. Bismuth silicate (BSO) and bismuth oxychloride (BiOCl) photocatalysts have unique layered structures and excellent visible - light absorption capabilities, and are important components of new photocatalytic materials. They can be compounded with TiO2 to improve the photocatalytic anti - fouling performance.

[0004] However, the current TiO2, BSO, and BiOCl photocatalysts are mainly in powder form and are difficult to be used alone in the anti - fouling field. If they can be effectively combined with PDMS while maintaining the light energy utilization rate and catalytic performance, the problem of low anti - fouling efficiency of PDMS - based temporary anti - fouling can be solved. Summary of the Invention

[0005] In order to overcome the above problems existing in the prior art, the purpose of the present invention is to provide a nano - island - shaped multifunctional temporary anti - fouling composite coating and a preparation method thereof, which have the characteristics of low cost, easy operation, non - toxicity, harmlessness, and short production cycle, and can improve the anti - fouling performance.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A preparation method of a nano - island - shaped multifunctional temporary anti - fouling composite coating includes the following steps;

[0008] Step (1): Mix the PDMS main agent and the curing agent, stir evenly, and brush - coat it on a glass slide;

[0009] Step (2): Add tetraethyl orthosilicate to absolute ethanol to form Solution A; add deionized water and ammonia water to absolute ethanol to form Solution B; drop Solution B into Solution A, stir to form a white precipitate, wash the precipitate alternately with deionized water and absolute ethanol by centrifugation, dry it, and grind it to obtain SiO2 powder;

[0010] Step (3): Dissolve bismuth nitrate pentahydrate in ethylene glycol to form Solution C; weigh sodium metasilicate nonahydrate and dissolve it in deionized water to form Solution D, drop Solution D into Solution C and continuously stir to obtain a white BSO precursor, load the white BSO precursor into a polytetrafluoroethylene reaction kettle, carry out a solvothermal reaction, after the reaction is completed, wash it alternately with deionized water and absolute ethanol by centrifugation, dry it, and grind it to obtain amorphous BSO powder;

[0011] Step (4): Dissolve titanium sulfate in deionized water to form Solution E; dissolve sodium hydroxide in 30 - 40 mL of deionized water to form Solution F; add Solution F to Solution E and stir; add the amorphous BSO powder and stir, wash it alternately with deionized water and absolute ethanol, dry it to form a TiO2 / amorphous BSO composite gel. Finally, calcine and grind the dried gel to obtain a crystalline TiO2 / amorphous BSO composite powder, denoted as TB composite powder;

[0012] Step (5): Dissolve the TB composite powder in deionized water, stir vigorously to form a suspension, use a nitric acid solution to adjust the pH value of the suspension, stir and then add a NaCl solution, stir vigorously, collect the mixed solution by centrifugation, wash it alternately with deionized water and absolute ethanol, and transfer it to a constant temperature drying oven to obtain a crystalline TiO2 / amorphous BSO / crystalline BiOCl composite powder, denoted as TBC composite powder;

[0013] Step (6): Disperse SiO2 and TBC composite powder in absolute ethanol respectively to obtain Solution G and Solution H;

[0014] Step (7): Ultrasonically disperse the obtained Solution G and Solution H, and then spray them onto the PDMS substrate one by one by the spraying method to obtain a PDMS - SiO2 - TBC composite coating material. The specific content of Step (1) is: Mix the PDMS main agent and the curing agent in a ratio of 10:1 - 13:1, stir for 5 - 10 min, and evenly brush - coat it on a glass slide to obtain a PDMS coating with a certain viscosity, that is, a nano - island - shaped multifunctional temporary anti - fouling composite coating.

[0015] The specific steps of step (2) are as follows: Measure 15 - 30 mL of absolute ethanol, add 2 - 8 mL of tetraethyl orthosilicate to form solution A; measure 15 - 30 mL of absolute ethanol, add 3 - 8 mL of deionized water and 3 - 5 mL of ammonia water to form solution B; after stirring evenly, add solution B dropwise to solution A and stir for 10 - 16 h, wash and centrifuge alternately with deionized water and absolute ethanol for 4 - 6 times, dry at 60℃ - 80℃, and grind to obtain monodisperse SiO2 powder.

[0016] The specific steps of step (3) are as follows: Weigh 5 - 6 mmol of bismuth nitrate pentahydrate and dissolve it in a mixed solution of 3 - 8 mL of deionized water and 5 - 10 mL of ethylene glycol, stir continuously for 30 - 60 min to form solution C; weigh 5 - 6 mmol of sodium metasilicate nonahydrate and dissolve it in 5 - 10 mL of deionized water to form solution D. After stirring evenly, add solution D dropwise to solution C and stir continuously for 30 - 60 min to obtain a white BSO precursor; put it into a 50 mL polytetrafluoroethylene reaction kettle, carry out solvothermal reaction at 100 - 130℃ for 10 - 14 h. After the reaction is completed, wash and centrifuge alternately with deionized water and absolute ethanol for 4 - 6 times, dry in an oven at 60 - 80℃ for 8 - 12 h, and grind to obtain amorphous BSO powder. By controlling the raw material ratio and hydrothermal conditions in this step, amorphous BSO is obtained, which will provide a basis for the generation of defects during the calcination process.

[0017] The specific steps of step (4) are as follows: Weigh 2 - 5 g of titanium sulfate and dissolve it in 30 - 70 mL of deionized water, stir continuously for 30 - 60 min to form solution E; weigh 0.3 - 0.6 g of sodium hydroxide and dissolve it in 30 - 40 mL of deionized water, stir continuously for 30 - 60 min to form solution F; add solution F to solution E, stir at 75 - 85℃ for 0.5 - 1.5 h; add the amorphous BSO powder obtained in step 3 and stir for 1 - 3 h, wash alternately with deionized water and absolute ethanol for 4 - 6 times, dry at 60 - 80℃ for 6 - 10 h, and then dry at 100 - 150℃ for 3 - 5 h; finally, put the dried sample into a furnace and calcine at 300 - 600℃ for 1 - 3 h, and grind to obtain crystalline TiO2 / amorphous BSO composite powder, denoted as TB composite powder. The ratio of this step can make TiO2 and amorphous BSO fully composite to form a heterojunction interface.

[0018] The (5) is specifically as follows: Weigh 0.2 - 0.3 g of TB composite powder, dissolve it in 20 - 30 mL of deionized water, and vigorously stir for 1 - 2 h to form a suspension. After using 0.5 - 1 mol / L nitric acid solution to adjust the pH value of the suspension to 1 - 2, stir for 15 - 30 min and then add 4 - 5 mL of NaCl solution with a mass concentration of 1.1 - 1.4 M respectively. After vigorously stirring for 30 - 60 min, collect and centrifuge the mixed solution, cross - wash it with deionized water and absolute ethanol for 4 - 6 times each, and then transfer it to a constant - temperature drying oven. Dry it at 60 - 80 °C for 8 - 12 h to obtain crystalline TiO2 / amorphous BSO / crystalline BiOCl composite powder, denoted as TBC, which is the nano - island - shaped multifunctional temporary anti - fouling composite coating. The raw material ratio of this step can make the ion - exchange process proceed fully to obtain crystalline TiO2 / amorphous BSO / crystalline BiOCl composite powder.

[0019] The PDMS - SiO2 - TBC composite coating material is nano - island - shaped. In the composite coating structure, the PDMS layer and the SiO2 layer are bonded by Si - O - Si bonds, and the SiO2 layer and the TBC are combined by electrostatic adsorption. PDMS serves as the composite coating substrate, and SiO2 serves as a photonic crystal to improve the overall light - energy utilization efficiency of the composite coating through nonlinear optical effects, etc. TBC provides photocatalytic degradation and sterilization performance.

[0020] The specific formation principle is as follows: First, during the preparation of BSO, due to insufficient hydrothermal temperature, it presents as strip - shaped amorphous; second, add a small amount of amorphous BSO to the TiO2 precursor, and after the sol - gel and calcination processes, the strip - shaped amorphous BSO is compounded on the surface of nano - island - shaped TiO2; finally, through the ion - exchange process, the [SiO3] 2- layer in BSO exchanges ions with Cl - in NaCl to form crystalline BiOCl on the surface of BSO. After the above reaction process, a crystal - crystalline - amorphous interface is formed.

[0021] The beneficial effects of the present invention:

[0022] A nano - island - shaped multifunctional temporary anti - fouling composite coating and its preparation method provided by the present invention combine PDMS, a photonic crystal, and a nano - island - shaped TiO2 - BSO - BiOCl (TBC) heterophotocatalyst. By constructing a photonic crystal - crystalline - amorphous interface, the temporary multifunctional anti - fouling performance of PDMS is effectively improved.

[0023] First, using crystalline TiO2 as the nanoisland matrix, amorphous BSO as the defect regulation carrier, and crystalline BiOCl as the microstructure regulator, the ion exchange process is used to break the atomic order of the defect states of amorphous BSO, induce a change in its dipole moment to generate a built-in electric field, act as an amorphous charge-driven interlayer, and match and couple with the local electric field in the photonic crystal to produce an enhancement effect, promoting the interfacial charge transfer of photonic crystal - crystalline TiO2 - amorphous BSO - crystalline BiOCl and improving the multifunctional pollutant protection performance.

[0024] Secondly, using the photonic crystal as an adsorbent to connect PDMS and the photocatalyst through electrostatic adsorption. The combination of the high defect states of the amorphous photocatalyst and the photonic crystal generates more light scattering centers and nonlinear optical effects, enhancing light absorption and scattering, increasing the energy density of light inside the material, and promoting the light absorption efficiency of the composite coating. In addition, this composite coating structure not only enhances the absorption of light inside the material but also optimizes the light absorption wavelength through the matching of the photon - electron bandgap, enabling the photocatalyst to more effectively utilize the light source and improving the efficiency of the photocatalytic reaction.

[0025] Finally, the above-mentioned multiple synergistic effects enhance the photocatalytic multifunctional anti-fouling performance of the composite coating. Description of the Drawings

[0026] Figure 1 TEM images, SAED patterns, and SEM images of TBC.

[0027] Figure 2 Schematic diagram of the antibacterial performance of the PDMS - SiO2 - TBC composite coating. Detailed Description of the Invention

[0028] The present invention will be further described in detail below with reference to the accompanying drawings.

[0029] Example 1:

[0030] A preparation method of a nano - island - shaped multifunctional temporary anti - fouling composite coating includes the following steps:

[0031] (1) Mix the PDMS main agent and the curing agent in a ratio of 10:1, stir for 10 min, and evenly brush - coat on a glass slide;

[0032] (2) Measure 25 mL of absolute ethanol, add 5 mL of tetraethyl orthosilicate to form solution A; measure 25 mL of absolute ethanol, add 5 mL of deionized water and 5 mL of ammonia water to form solution B. After stirring evenly, add solution B drop - by - drop to solution A and stir for 10 h. Wash and centrifuge alternately with deionized water and absolute ethanol 6 times, dry at 60 °C, and grind to obtain SiO2 powder;

[0033] (3) Weigh 6 mmol of bismuth nitrate pentahydrate and dissolve it in a mixed solution formed by 4 mL of ethylene glycol and 7 mL of ethylene glycol, and continuously stir for 30 min to form Solution C; weigh 6 mmol of sodium metasilicate nonahydrate and dissolve it in 7 mL of deionized water to form Solution D. After stirring evenly, add Solution D dropwise to Solution C and continuously stir for 30 min to obtain a white BSO precursor. Load it into a 50 mL polytetrafluoroethylene reaction kettle and carry out a solvothermal reaction at 100 °C for 12 h. After the reaction is completed, wash and centrifuge it alternately with deionized water and absolute ethanol 6 times, dry it in an oven at 60 °C for 8 h, and grind it to obtain amorphous BSO powder.

[0034] (4) Weigh 3 g of titanium sulfate and dissolve it in 50 mL of deionized water, and continuously stir for 30 min to form Solution E; weigh 0.5 g of sodium hydroxide and dissolve it in 38 mL of deionized water, and continuously stir for 30 min to form Solution F; add Solution F to Solution E and stir at 85 °C for 1 h; add the amorphous BSO powder obtained in step 3 and stir for 2 h, wash it alternately with deionized water and absolute ethanol several times, dry it at 80 °C for 8 h, and then dry it at 130 °C for 3 h; finally, put the dried sample into a furnace and calcine it at 500 °C for 2 h, and grind it to obtain crystalline TiO2 / amorphous BSO composite powder, denoted as TB;

[0035] (5) Weigh 0.26 g of TB composite powder and dissolve it in 30 mL of deionized water. After vigorously stirring for 2 h to form a suspension, use 1 mol / L nitric acid solution to adjust the pH value of the suspension to 1, stir for 30 min, then add 5 mL of a 1.2 M NaCl solution with a mass concentration, stir vigorously for 30 min, collect and centrifuge the mixed solution, cross-wash it with deionized water and absolute ethanol 6 times each, and transfer it to a constant temperature drying oven. Dry it at 60 °C for 12 h to obtain crystalline TiO2 / amorphous BSO / crystalline BiOCl composite powder, denoted as TBC.

[0036] (6) Disperse SiO2 and TBC composite powders in absolute ethanol respectively to obtain Solution G and Solution H;

[0037] (7) Ultrasonically disperse the obtained Solution G and Solution H, and then spray them onto the PDMS substrate one by one by the spraying method to obtain a PDMS-SiO2-TBC composite coating material;

[0038] The PDMS-SiO2-TBC composite coating material obtained through this example has good mechanical properties, and the photocatalytic degradation of organic matter and antibacterial properties almost reach 100%, and the overall protection performance is optimal.

[0039] Example 2:

[0040] A preparation method of a nano-island-shaped multifunctional temporary anti-fouling composite coating, comprising the following steps:

[0041] (1) Mix the PDMS base agent and the curing agent in a ratio of 11:1, stir for 8 min, and evenly brush it on the glass slide.

[0042] (2) Measure 30 mL of absolute ethanol, add 5 mL of tetraethyl orthosilicate to form solution A; measure 30 mL of absolute ethanol, add 5 mL of deionized water and 5 mL of ammonia water to form solution B. After stirring evenly, add solution B dropwise to solution A and then stir for 12 h. Wash and centrifuge alternately with deionized water and absolute ethanol 4 times, dry at 80 °C, and grind to obtain SiO2 powder.

[0043] (3) Weigh 7 mmol of bismuth nitrate pentahydrate and dissolve it in a mixed solution of 4 mL and 7 mL of ethylene glycol, continuously stir for 30 min to form solution C; weigh 7 mmol of sodium metasilicate nonahydrate and dissolve it in 7 mL of deionized water to form solution D. After stirring evenly, add solution D dropwise to solution C and continuously stir for 40 min to obtain a white BSO precursor. Put it into a 50 mL polytetrafluoroethylene reaction kettle and carry out solvothermal reaction at 110 °C for 10 h. After the reaction is completed, wash and centrifuge alternately with deionized water and absolute ethanol 4 times, dry in an oven at 80 °C for 10 h, and grind to obtain amorphous BSO powder.

[0044] (4) Weigh 3.5 g of titanium sulfate and dissolve it in 50 mL of deionized water, continuously stir for 40 min to form solution E; weigh 0.4 g of sodium hydroxide and dissolve it in 40 mL of deionized water, continuously stir for 30 min to form solution F; add solution F to solution E and stir at 80 °C for 1.5 h; add the amorphous BSO powder obtained in step 3 and stir for 2 h, wash 4 times alternately with deionized water and absolute ethanol, dry at 80 °C for 10 h, and then dry at 140 °C for 2 h; finally, put the dried sample into a furnace at 450 °C and calcine for 3 h, and grind to obtain crystalline TiO2 / amorphous BSO composite powder, denoted as TB.

[0045] (5) Weigh 0.3 g of TB composite powder, dissolve it in 30 mL of deionized water, and form a suspension after vigorously stirring for 1 h. After adjusting the pH value of the suspension to 1 with 0.5 mol / L nitric acid solution, stir for 40 min and then add 4 mL of 1.3 M NaCl solution by mass concentration respectively. After vigorously stirring for 40 min, collect and centrifuge the mixed solution, wash it 4 times alternately with deionized water and absolute ethanol, and then transfer it to a constant temperature drying oven and dry at 80 °C for 10 h to obtain crystalline TiO2 / amorphous BSO / crystalline BiOCl composite powder, denoted as TBC.

[0046] (6) Disperse the SiO2 and TBC composite powders in absolute ethanol respectively to obtain solution G and solution H.

[0047] (7) The obtained Solution G and Solution H were ultrasonically dispersed and then sprayed onto the PDMS substrate one by one using the spraying method to obtain the PDMS-SiO2-TBC composite coating material;

[0048] The PDMS-SiO2-TBC composite coating material obtained through this example has relatively good mechanical properties, good photocatalytic degradation of organic matter and antibacterial properties, and excellent overall protection performance.

[0049] Example 3:

[0050] A preparation method of a nano-island multi-functional temporary anti-fouling composite coating, comprising the following steps:

[0051] (1) Mix the PDMS main agent and the curing agent in a ratio of 12:1, stir for 10 min, and evenly brush-coat on the glass slide;

[0052] (2) Measure 20 mL of absolute ethanol, add 4 mL of tetraethyl orthosilicate to form Solution A; measure 20 mL of absolute ethanol, add 4 mL of deionized water and 4 mL of ammonia water to form Solution B. After stirring evenly, add Solution B dropwise to Solution A and stir for 14 h. Wash and centrifuge alternately with deionized water and absolute ethanol 6 times, dry at 80 °C, and grind to obtain SiO2 powder;

[0053] (3) Weigh 5 mmol of bismuth nitrate pentahydrate and dissolve it in a mixed solution of 5 mL and 6 mL of ethylene glycol, continuously stir for 25 min to form Solution C; weigh 5 mmol of sodium metasilicate nonahydrate and dissolve it in 6 mL of deionized water to form Solution D. After stirring evenly, add Solution D dropwise to Solution C and continuously stir for 25 min to obtain a white BSO precursor. Put it into a 50 mL polytetrafluoroethylene reaction kettle and carry out a solvothermal reaction at 120 °C for 12 h. After the reaction is completed, wash and centrifuge alternately with deionized water and absolute ethanol 6 times, dry in an oven at 60 °C for 12 h, and grind to obtain amorphous BSO powder.

[0054] (4) Weigh 4 g of titanium sulfate and dissolve it in 40 mL of deionized water, continuously stir for 30 min to form Solution E; weigh 0.3 g of sodium hydroxide and dissolve it in 30 mL of deionized water, continuously stir for 20 min to form Solution F; add Solution F to Solution E and stir at 85 °C for 2 h; add the amorphous BSO powder obtained in step 3 and stir for 1.5 h, wash alternately with deionized water and absolute ethanol 6 times, dry at 60 °C for 12 h, and then dry at 130 °C for 3 h; finally, put the dried sample into a muffle furnace at 400 °C and calcine for 3 h, and grind to obtain the crystalline TiO2 / amorphous BSO composite powder, denoted as TB;

[0055] (5) Weigh 0.2 g of the TB composite powder and dissolve it in 20 mL of deionized water. After vigorously stirring for 0.5 h to form a suspension, use 0.5 mol / L nitric acid solution to adjust the pH value of the suspension to 2. After stirring for 30 min, add 5 mL of 1.1 M NaCl solution with a mass concentration respectively. After vigorously stirring for 30 min, collect and centrifuge the mixed solution. After cross-washing with deionized water and absolute ethanol for 6 times each, transfer it to a constant temperature drying oven and dry it at 60 °C for 12 h to obtain crystalline TiO2 / amorphous BSO / crystalline BiOCl composite powder, denoted as TBC.

[0056] (6) Disperse the SiO2 and TBC composite powders in absolute ethanol respectively to obtain solution G and solution H.

[0057] (7) Ultrasonically disperse the obtained solution G and solution H, and then spray them onto the PDMS substrate one by one by the spraying method to obtain the PDMS-SiO2-TBC composite coating material.

[0058] The PDMS-SiO2-TBC composite coating material obtained through this example has relatively good photocatalytic degradation of organic matter and antibacterial properties, and excellent overall protection performance.

[0059] From Figure 1 the TEM image shown in Fig. a, it can be seen that there are obvious crystalline-amorphous-crystalline interfaces in the TBC sample, proving the effective construction of the composite structure. From Figure 1 the SAED pattern in Fig. b, it can be seen that there are both polycrystalline diffraction spots and amorphous diffraction rings in the TBC sample, further corroborating the formation of the crystalline-amorphous-crystalline interface. From Figure 1 the SEM image in Fig. c, it can be seen that BSO and BiOCl are attached to the surface of island-like TiO2, confirming its morphological structure. As Figure 2 shown, the bactericidal rate of the PDMS-SiO2-TBC composite coating against Escherichia coli and Staphylococcus aureus almost reaches 100%, showing excellent antibacterial effects.

Claims

1. A method for preparing a nano-island multifunctional temporary anti-fouling composite coating, characterized in that: The steps include: Step (1): Mix the PDMS main agent and the curing agent, and evenly apply them on the glass slide; Step (2): adding ethyl orthosilicate to anhydrous ethanol to form liquid A; adding deionized water and ammonia water to anhydrous ethanol to form liquid B; adding liquid B dropwise to liquid A to form a white precipitate after stirring, and washing the precipitate with deionized water and anhydrous ethanol alternately, centrifuging, drying, and grinding to obtain SiO2 powder; Step (3): dissolving bismuth nitrate pentahydrate in ethylene glycol to form liquid C; weighing sodium metasilicate nonahydrate and dissolving it in deionized water to form liquid D; adding liquid D dropwise into liquid C and continuously stirring to obtain a white BSO precursor; placing the white BSO precursor into a polytetrafluoroethylene reactor, and subjecting it to a solvent thermal reaction; after the reaction is completed, washing with deionized water and anhydrous ethanol alternately, drying, and grinding to obtain an amorphous BSO powder; Step (4): dissolving titanium sulfate in deionized water to form liquid E; dissolving sodium hydroxide in deionized water to form liquid F; adding liquid F to liquid E and stirring; adding the amorphous BSO powder and stirring, washing and drying alternately with deionized water and anhydrous ethanol to form a TiO2 / amorphous BSO composite gel; finally, calcining and grinding the dried gel to obtain a crystalline TiO2 / amorphous BSO composite powder, which is recorded as TB composite powder; Step (5): dissolving the TB composite powder in deionized water, stirring vigorously to form a suspension, adjusting the pH value of the suspension with a nitric acid solution, adding a NaCl solution after stirring, collecting the mixed solution by centrifugation after vigorous stirring, cross-washing with deionized water and anhydrous ethanol, and transferring to a constant temperature drying oven to obtain a crystalline TiO2 / amorphous BSO / crystalline BiOCl composite powder, recorded as TBC composite powder; Step (6): Dispersing SiO2 and TBC composite powders in anhydrous ethanol respectively to obtain liquid G and liquid H; Step (7): After ultrasonically dispersing the obtained G solution and H solution, spray them onto the PDMS substrate one by one using a spraying method to obtain a PDMS-SiO2-TBC composite coating material.

2. The method for preparing a nano-island multifunctional temporary anti-fouling composite coating according to claim 1, characterized in that: The step (1) specifically comprises: mixing the PDMS main agent and the curing agent in a ratio of 10:1-13:1, stirring for 5-10 minutes, and evenly brushing the mixture on a glass slide to obtain a PDMS coating with a certain viscosity.

3. The method for preparing a nano-island multifunctional temporary anti-fouling composite coating according to claim 1, characterized in that: The step (2) is specifically as follows: measuring 15-30 mL of anhydrous ethanol, adding 2-8 mL of tetraethyl orthosilicate to form liquid A; measuring 15-30 mL of anhydrous ethanol, adding 3-8 mL of deionized water and 3-5 mL of ammonia water to form liquid B; after stirring evenly, adding liquid B dropwise to liquid A and stirring for 10-16 hours, washing with deionized water and anhydrous ethanol alternately, centrifuging 4-6 times, drying at 60° C.-80° C., and grinding to obtain monodisperse SiO2 powder.

4. The method for preparing a nano-island multifunctional temporary anti-fouling composite coating according to claim 1, characterized in that: The step (3) is specifically as follows: weighing 5-6 mmol of bismuth nitrate pentahydrate and dissolving it in a mixed solution formed by 3-8 mL of deionized water and 5-10 mL of ethylene glycol, and continuously stirring for 30-60 min to form liquid C; weighing 5-6 mmol of sodium metasilicate nonahydrate and dissolving it in 5-10 mL of deionized water to form liquid D, stirring it uniformly, then dropping the liquid D into the liquid C and continuously stirring it for 30-60 min to obtain a white BSO precursor; placing it into a polytetrafluoroethylene reactor, and performing a solvent thermal reaction at 100-130° C. for 10-14 h. After the reaction is completed, washing it with deionized water and anhydrous ethanol alternately and centrifuging it for 4-6 times, drying it in an oven at 60-80° C. for 8-12 h, and grinding it to obtain an amorphous BSO powder.

5. The method for preparing a nano-island multifunctional temporary anti-fouling composite coating according to claim 1, characterized in that: The step (4) is specifically as follows: weigh 2-5 g of titanium sulfate and dissolve it in 30-70 mL of deionized water, and continue to stir for 30-60 min to form liquid E; weigh 0.3-0.6 g of sodium hydroxide and dissolve it in 30-40 mL of deionized water, and continue to stir for 30-60 min to form liquid F; add liquid F to liquid E and stir at 75-85° C. for 0.5-1.5 h; add the amorphous BSO powder obtained in step 3 and stir for 1-3 h, wash it alternately with deionized water and anhydrous ethanol for 4-6 times, dry it at 60-80° C. for 6-10 h, and then dry it at 100-150° C. for 3-5 h; finally, calcine the dried sample at 300-600° C. for 1-3 h, and grind it to obtain a crystalline TiO2 / amorphous BSO composite powder, which is recorded as TB composite powder.

6. The method for preparing a nano-island multifunctional temporary anti-fouling composite coating according to claim 1, characterized in that: The method (5) is specifically as follows: 0.2-0.3 g of TB composite powder is weighed, dissolved in 20-30 mL of deionized water, and vigorously stirred for 1-2 h to form a suspension. After adjusting the pH value of the suspension to 1-2 with 0.5-1 mol / L nitric acid solution, 4-5 mL of a 1.1-1.4 M NaCl solution is added after stirring for 15-30 min. After vigorously stirring for 30-60 min, the mixed solution is collected and centrifuged, cross-washed with deionized water and anhydrous ethanol for 4-6 times each, and then transferred to a constant temperature drying oven, and dried at 60-80° C. for 8-12 h to obtain a crystalline TiO2 / amorphous BSO / crystalline BiOCl composite powder, denoted as TBC, i.e., a nano-island multifunctional temporary anti-fouling composite coating.

7. The PDMS-SiO2-TBC composite coating material prepared according to the method according to any one of claims 1 to 6, characterized in that: The PDMS-SiO2-TBC composite coating material is in the shape of nano-islands. In the composite coating structure, the PDMS layer and the SiO2 layer are bonded to each other by Si-O-Si bonds, and the SiO2 layer and the TBC are bonded by electrostatic adsorption. PDMS serves as the composite coating substrate, and SiO2 serves as a photonic crystal to improve the overall light energy utilization efficiency of the composite coating through nonlinear optical effects, and TBC provides photocatalytic degradation and bactericidal properties.

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