Preparation method and application of anti-fouling coating material with electrostatic repulsion effect

Abstract

The invention relates to the technical field of marine equipment antifouling, in particular to a preparation method and application of an electrostatic repulsion antifouling coating material, and the preparation method comprises the following steps: S1, adding quantitative fluorinated graphene and tetraethylammonium chloride into organic silicon resin, grinding and dispersing uniformly to obtain a dispersed resin matrix; s2, dimethyl silicon dioxide and a silane coupling agent KH580 are added into the resin matrix obtained in the step S1 to be evenly mixed, and the antifouling coating material is obtained.The water medium and the surface of the antifouling coating material are in frictional contact for electrification, an electrified surface is formed, repulsive interaction is generated, and therefore antifouling is achieved, and the antifouling coating material can be suitable for the marine environment and has good application prospects. And the FG on the surface of the coating has high stability, is non-toxic and harmless, and is very environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of antifouling of marine equipment, and in particular to a preparation method and application of an antifouling coating material with electrostatic repulsion. Background Art

[0002] Marine equipment is immersed in the seawater interface, and it is inevitable that marine organisms will adhere to the equipment coating surface. The attachment and proliferation of fouling organisms will, on the one hand, increase the ship's navigation resistance, reduce the speed, and greatly increase fuel consumption; on the other hand, it will increase the roughness of the inner wall of the equipment's piping system, reduce the inner diameter of the pipeline, make it difficult for seawater to flow, and cause erosion and corrosion.

[0003] At present, there are three main technologies for antifouling in marine environments at home and abroad: 1. Physical antifouling technology, 2. Electrochemical antifouling technology, and 3. Biomimetic antifouling technology. Physical antifouling refers to physical removal or physical methods to reduce or prevent the attachment of fouling organisms, so as to achieve the purpose of antifouling, such as ultrasonic antifouling method, but ultrasonic antifouling method requires huge energy consumption, and the impact of high-frequency sound waves on the hull structure, on the crew, and on the impact of antifouling coatings has not been thoroughly studied. Electrochemical antifouling technology mainly uses chemical substances generated by electrolysis to inhibit the growth of fouling organisms or directly kill them. The biggest disadvantage of electrochemical antifouling technology is that it consumes a large amount of heavy metals and causes environmental pollution. Biomimetic antifouling technology uses the biomimetic coating method. A variety of biocides including tributyltin, cuprous oxide, copper pyrithione and isothiazolinone are incorporated into the coating, thereby giving the biomimetic coating excellent antifouling properties. Although the above technologies have demonstrated significant antifouling effects, they will release antifouling agents into the marine environment, which may cause a certain degree of pollution to the ecosystem. In addition, with the release of antifouling agents, a saponification layer will gradually form on the surface of the coating, resulting in increased surface roughness, which not only affects the appearance of the coating, but may also have an adverse effect on reducing resistance and improving energy efficiency. Summary of the invention

[0004] In order to overcome the deficiencies in the prior art, the present invention provides a preparation method and application of an electrostatic repulsion antifouling coating material.

[0005] To achieve the above object, the preparation method of the electrostatic repulsion antifouling coating material disclosed in the present invention comprises the following steps: S1: adding a certain amount of fluorinated graphene and tetraethylammonium chloride into a silicone resin, grinding and dispersing them uniformly to obtain a dispersed resin matrix; S2: adding dimethyl silica and silane coupling agent KH580 to the resin matrix obtained in step S1 and mixing them evenly to obtain an antifouling coating material.

[0006] Preferably, the fluorinated graphene is prepared by a mild liquid phase reaction using graphene oxide and trifluoromethanesulfonic acid as raw materials, and the preparation method comprises the following steps: S101: adding a certain amount of graphene oxide powder to a mixed solvent of methanol, ethanol and acetone, and stirring the mixture to promote dispersion; S102: placing the mixture in an ice water bath, adding trifluoromethanesulfonic acid dropwise three times, performing ultrasonic dispersion for 8 hours and then switching to magnetic stirring for 48 hours; S103: filtering the mixture, washing it with acetone and deionized water, and vacuum drying it to obtain fluorinated graphene.

[0007] Preferably, in parts by weight, the amount of the silicone resin is 45 to 75 parts, the amount of the fluorinated graphene is 0.5 to 10 parts, the amount of tetraethylammonium chloride is 10 to 30 parts, the amount of dimethyl silica is 5 to 20 parts, and the amount of the silane coupling agent KH580 is 2 to 20 parts.

[0008] Preferably, the grinding time in step S1 is 30 to 60 minutes, and the grinding speed is 400 to 800 rpm; the mixing time in step S2 is 5 to 30 minutes, and the mixing speed is 100 to 300 rpm.

[0009] Preferably, in step S103, the number of cleaning times is 3 times, the vacuum drying temperature is 60° C., and the vacuum drying time is 24 hours.

[0010] Preferably, the amount of graphene oxide powder is 0.05-0.1 g, the amount of mixed solvent is 100-200 mL, the volume ratio of methanol, ethanol and acetone in the mixed solvent is 1:4:5, and the amount of trifluoromethanesulfonic acid is 1-2 mL.

[0011] The present invention also provides an application of an electrostatic repulsion antifouling coating material prepared by the preparation method of the electrostatic repulsion antifouling coating material, which is applied to marine equipment. The electrostatic repulsion antifouling coating material forms a negative charge on the friction surface with seawater, and the negative charge generates electrostatic repulsion with negatively charged fouling organic matter, thereby inhibiting the fouling organic matter from approaching the electrostatic repulsion antifouling coating material.

[0012] The beneficial effects of the present invention are: 1. The present invention utilizes the friction between the water medium and the surface of the antifouling coating material to generate electricity, forming a charged surface and generating a repulsive effect, thereby achieving antifouling. It can be applied to the marine environment, and the energy of the water medium itself, such as droplet energy, wave energy and other high entropy energy, can be directly converted into electrical energy in the form of contact friction to act on the surface of the antifouling coating material. A self-sufficient energy conversion form can be achieved without the supply of an external power supply. The converted electrical energy is reflected in the output of frictional electrical energy between the antifouling coating material and the water medium. The greater the output electrical energy, the greater the number of frictional charges generated on the surface, which is conducive to enhancing the electrostatic repulsion between the coating and the fouling organic matter.

[0013] 2. The electrostatic repulsion between the surface of the antifouling coating material and the fouling organic matter is a non-contact antifouling form. The surface of the antifouling coating material generates a strong negative potential, which produces an enhanced repulsion effect with the fouling organic matter. The fouling organic matter cannot get close to the surface of the coating material, and protection is provided from the source of the pollutants contacting the surface of the polluted coating material, avoiding the attachment of large fouling organisms due to the attachment of fouling organic matter.

[0014] 3. The charged antifouling technology of antifouling coating materials only involves the conversion of energy. The fluorinated graphene (FG) on the surface of the antifouling coating material itself is highly stable, non-toxic and harmless, and very friendly to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 : is an XPS characterization diagram of the fluorinated graphene with triboelectric negativity in the present invention; wherein a is a comparison of XPS spectra of GO and FG, b is a C1s spectrum of FG, c is a F1s spectrum of FG, and d is an element spectrum of FG, wherein GO represents graphene oxide and FG represents fluorinated graphene; Figure 2 : is a SEM characterization image of the fluorinated graphene in the present invention; wherein a is a SEM image of FG, and b is a SEM image of the coating of Example 1, wherein FG represents fluorinated graphene; Figure 3 This is the electrical performance output diagram of the frictional contact between the coating and water in Example 1 of the present invention; wherein a is the short-circuit current output, and b is the open-circuit voltage output; Figure 4 The antifouling effect of the electrostatic repulsion of the coating of Example 1 and Comparative Example 1 of the present invention is compared; wherein a is the electrostatic repulsion antifouling effect of γ-PGA, and b is the electrostatic repulsion antifouling effect of SA; Figure 5 Schematic diagram of the electrostatic repulsion of pollutants by the antifouling coating material of the present invention. DETAILED DESCRIPTION

[0016] The following is combined with Figure 1 To Attachment Figure 5The principles and features of the present invention are described, and the examples given are only used to explain the present invention, rather than to limit the scope of the present invention.

[0017] The working principle of the present invention is: by utilizing the coupling effect of triboelectric charging and electrostatic induction, when the friction layer and the water medium are rubbed, negative charges will be instantly generated on the surface to form a negatively charged surface. The intensity of the electrostatic repulsion is closely related to the charge density of the surface of the triboelectric coating, and a high surface charge density can produce a stronger repulsive force. The fluorinated graphene coating used in the present invention has high triboelectric negativity due to the CF bonds with a high F / C ratio. The presence of the CF bonds produces a strong attraction for the electrons in the water molecules during the friction between the coating and the seawater. In addition, during the friction process, the high-density CF bonds will enhance the electron transfer between the F atoms and the water molecules, increase the charge density of the coating surface, thereby producing a strong electrostatic repulsion effect, and inhibiting the attachment of organic matter that fouls the conditional membrane.

[0018] The functions of each component in this method are as follows: Graphene fluoride: enhances the triboelectric effect by enhancing surface charge accumulation, regulating electronic properties and improving chemical stability. Silicone resin: as a substrate or coating material, it provides excellent flexibility, chemical stability and durability, and improves the stability and durability of triboelectric materials. Tetraethylammonium chloride: through its ionization properties, interaction with the material surface, and regulation of charge distribution. Dimethyl silica: provides excellent surface properties, chemical stability, flexibility and crack resistance, and can improve the friction performance and durability of triboelectric materials, especially in long-term friction environments. Silane coupling agent KH580: enhances the bonding force between the filler and the organic matrix in the triboelectric material, improves the charge accumulation and transfer performance of the material, and improves the aging resistance and triboelectric effect of the material.

[0019] Example 1: An electrostatic repulsion antifouling coating material prepared by mixing organic silicone resin, fluorinated graphene, tetraethylammonium chloride, dimethyl silicon dioxide, and silane coupling agent KH580, and its preparation method comprises the following steps: S1: adding a certain amount of fluorinated graphene and tetraethylammonium chloride to the silicone resin, placing the mixture in a grinder, grinding at a speed of 600 rpm for 60 min, and grinding and dispersing the mixture uniformly to obtain a dispersed resin matrix; S2: Add dimethyl silica and silane coupling agent KH580 to the resin matrix obtained in step S1 and mix them evenly at a mixing speed of 100 rpm for 10 min to obtain an antifouling coating material.

[0020] In this embodiment, by weight, the amount of organic silicone resin is 65 parts, the amount of fluorinated graphene is 5 parts, the amount of tetraethylammonium chloride is 20 parts, the amount of dimethyl silica is 5 parts, and the amount of silane coupling agent KH580 is 5 parts.

[0021] Preferably, the fluorinated graphene is prepared by a mild liquid phase reaction using graphene oxide and trifluoromethanesulfonic acid as raw materials, and the preparation method thereof comprises the following steps: S101: adding 0.1 g of graphene oxide powder to a mixed solvent of methanol, ethanol and acetone, wherein the total amount of the mixed solvent is 200 mL, and the volume ratio of methanol, ethanol and acetone in the mixed solvent is 1:4:5, and stirring the mixture to promote dispersion; S102: Place the mixture in an ice water bath, add 2 mL of trifluoromethanesulfonic acid three times, and perform ultrasonic dispersion for 8 hours, then change to magnetic stirring for 48 hours; S103: Filter the mixture, wash it with acetone and deionized water for three times, and vacuum dry it at 60° C. for 24 hours to obtain fluorinated graphene.

[0022] Example 2: A method for preparing an antifouling coating material with electrostatic repulsion effect by mixing an organic silicone resin, fluorinated graphene, tetraethylammonium chloride, dimethyl silicon dioxide, and a silane coupling agent KH580, the preparation method comprising the following steps: S1: adding a certain amount of fluorinated graphene and tetraethylammonium chloride to the silicone resin, placing the mixture in a grinder, grinding at a speed of 400 rpm for 35 min, and grinding and dispersing the mixture uniformly to obtain a dispersed resin matrix; S2: Add dimethyl silica and silane coupling agent KH580 to the resin matrix obtained in step S1 and mix them evenly at a mixing speed of 300 rpm for 30 min to obtain an antifouling coating material.

[0023] In this embodiment, by weight, the amount of the silicone resin is 75 parts, the amount of the fluorinated graphene is 1 part, the amount of tetraethylammonium chloride is 10 parts, the amount of dimethyl silica is 12 parts, and the amount of the silane coupling agent KH580 is 2 parts.

[0024] Preferably, the fluorinated graphene is prepared by a mild liquid phase reaction using graphene oxide and trifluoromethanesulfonic acid as raw materials, and the preparation method thereof comprises the following steps: S101: adding 0.05 g of graphene oxide powder to a mixed solvent of methanol, ethanol and acetone, wherein the total amount of the mixed solvent is 100 mL, and the volume ratio of methanol, ethanol and acetone in the mixed solvent is 1:4:5, and stirring the mixture to promote dispersion; S102: Place the mixture in an ice water bath, add 1 mL of trifluoromethanesulfonic acid three times, and perform ultrasonic dispersion for 8 hours, then change to magnetic stirring for 48 hours; S103: Filter the mixture, wash it with acetone and deionized water for three times, and vacuum dry it at 60° C. for 24 hours to obtain fluorinated graphene.

[0025] Example 3: A method for preparing an antifouling coating material with electrostatic repulsion effect by mixing an organic silicone resin, fluorinated graphene, tetraethylammonium chloride, dimethyl silicon dioxide, and a silane coupling agent KH580, the preparation method comprising the following steps: S1: adding a certain amount of fluorinated graphene and tetraethylammonium chloride to the silicone resin, placing the mixture in a grinder, grinding at a speed of 800 rpm for 30 min, and grinding and dispersing the mixture uniformly to obtain a dispersed resin matrix; S2: Add dimethyl silica and silane coupling agent KH580 to the resin matrix obtained in step S1 and mix them evenly at a mixing speed of 200 rpm for 5 min to obtain an antifouling coating material.

[0026] In this embodiment, by weight, the amount of organic silicone resin is 50 parts, the amount of fluorinated graphene is 10 parts, the amount of tetraethylammonium chloride is 30 parts, the amount of dimethyl silica is 5 parts, and the amount of silane coupling agent KH580 is 5 parts.

[0027] Preferably, the fluorinated graphene is prepared by a mild liquid phase reaction using graphene oxide and trifluoromethanesulfonic acid as raw materials, and the preparation method thereof comprises the following steps: S101: adding 0.08 g of graphene oxide powder to a mixed solvent of methanol, ethanol and acetone, wherein the total amount of the mixed solvent is 150 mL, and the volume ratio of methanol, ethanol and acetone in the mixed solvent is 1:4:5, and stirring the mixture to promote dispersion; S102: Place the mixture in an ice water bath, add 1.5 mL of trifluoromethanesulfonic acid three times, and perform ultrasonic dispersion for 8 hours, then change to magnetic stirring for 48 hours; S103: Filter the mixture, wash it with acetone and deionized water for three times, and vacuum dry it at 60° C. for 24 hours to obtain fluorinated graphene.

[0028] Example 4: A method for preparing an antifouling coating material with electrostatic repulsion effect by mixing an organic silicone resin, fluorinated graphene, tetraethylammonium chloride, dimethyl silicon dioxide, and a silane coupling agent KH580, the preparation method comprising the following steps: S1: adding a certain amount of fluorinated graphene and tetraethylammonium chloride to the silicone resin, placing the mixture in a grinder, grinding at a speed of 600 rpm for 60 min, and grinding and dispersing the mixture uniformly to obtain a dispersed resin matrix; S2: Add dimethyl silica and silane coupling agent KH580 to the resin matrix obtained in step S1 and mix them evenly at a mixing speed of 100 rpm for 10 min to obtain an antifouling coating material.

[0029] In this embodiment, by weight, the amount of organic silicone resin is 45 parts, the amount of fluorinated graphene is 5 parts, the amount of tetraethylammonium chloride is 10 parts, the amount of dimethyl silica is 20 parts, and the amount of silane coupling agent KH580 is 20 parts.

[0030] Preferably, the fluorinated graphene is prepared by a mild liquid phase reaction using graphene oxide and trifluoromethanesulfonic acid as raw materials, and the preparation method thereof comprises the following steps: S101: adding 0.1 g of graphene oxide powder to a mixed solvent of methanol, ethanol and acetone, wherein the total amount of the mixed solvent is 200 mL, and the volume ratio of methanol, ethanol and acetone in the mixed solvent is 1:4:5, and stirring the mixture to promote dispersion; S102: Place the mixture in an ice water bath, add 2 mL of trifluoromethanesulfonic acid three times, and perform ultrasonic dispersion for 8 hours, then change to magnetic stirring for 48 hours; S103: Filter the mixture, wash it with acetone and deionized water for three times, and vacuum dry it at 60° C. for 24 hours to obtain fluorinated graphene.

[0031] Comparative Example 1: The difference from the above-mentioned Example 1 is that no fluorinated graphene is added in the process of preparing the antifouling coating material in Comparative Example 1, and the preparation method thereof comprises the following steps: S1: Add tetraethylammonium chloride to the silicone resin, place in a grinder, mix at 400 rpm for 30 min, grind and disperse evenly to obtain a dispersed resin matrix for standby use, wherein the amount of tetraethylammonium chloride is 30 parts by weight and the amount of silicone resin is 60 parts by weight; S2: Add dimethyl silica and silane coupling agent KH580 to the dispersed resin matrix, mix at 100 rpm for 5 minutes, and mix evenly to obtain an antifouling coating material. By weight, the amount of dimethyl silica is 8 parts, and the amount of silane coupling agent KH580 is 2 parts.

[0032] like Figure 1 As shown, X-ray photoelectron spectroscopy (XPS) was used to characterize the detailed information of functional group transformation during the reaction, such as Figure 1 As shown in a, in the XPS spectrum of graphene oxide (GO), only two peaks were observed, located at around 286 and 533 eV, which can be attributed to the C1s and O1s nuclear energy level peaks, while the fluorinated graphene (FG) product showed two additional peaks at 688.8 and 833.8 eV, which came from CF and CF, respectively. 2 and CF 3 The F1s core level and Auger electrons of the cell. In addition, Figure 1As shown in (b), in the C1s peak of fluorinated graphene (FG), new components at around 284.8, 285.9, 286.7, 288.5, 289.7, 291.6, and 292.9 eV are obtained by better deconvolution and can be attributed to -CC-, C-CF, C-CF 2 , CF, CF-CF 2 CF 2 and CF 3 Part. Figure 1 As shown in c, CF, CF 2 and CF 3 The existence of the unit is further confirmed by the F1s core level components located at around 687, 689, and 691 eV, respectively. Figure 1 As shown in d, in addition, the elemental analysis results show that 19.29wt% F element was successfully introduced into the structure. These observations indicate that the oxygen-containing functional groups were successfully converted into fluorinated units and fluorinated graphene was successfully prepared.

[0033] like Figure 2 As shown in a, the SEM image of fluorinated graphene (FG) shows a disordered sheet structure. Figure 2 As shown in b, in addition to retaining the lamellar structure of fluorinated graphene (FG) on the coating surface of Example 1, the addition of fluorinated graphene (FG) also increases the roughness of the coating surface, which is beneficial to increasing the contact area between water and the coating, increasing the surface charge density, and enhancing the electrostatic repulsion.

[0034] like Figure 3 As shown, the antifouling coating material prepared in Example 1 generates a voltage of 0.5 V and a current of 0.02 mA in triboelectric response with water medium. The fluorinated graphene (FG) coating exhibits good triboelectric contact electrification performance, can form a charged surface with a high negative charge density, can generate electrostatic repulsion with fouling organic matter, and realize the anti-attachment of organic matter on the coating surface.

[0035] like Figure 4 and Figure 5As shown, the antifouling comparison of the electrostatic repulsion effect of the fluorinated graphene (FG) antifouling coating material obtained by the above-mentioned Example 1 and the organic matter (γ-PGA, SA), and the comparative example 1 is the antifouling effect of the friction contact electrification form of the non-fluorinated graphene material. From the comparison results, the antifouling effect of the electrostatic repulsion effect of the fluorinated graphene (FG) antifouling coating material and the conditional membrane organic matter is increased by 2.9 times and 3.4 times respectively. The results show that the fluorinated graphene (FG) electrostatic coating exhibits a good antifouling effect. The reason why the antifouling effect of comparative example 1 is insufficient is that the ionization of tetraethylammonium chloride itself neutralizes the friction charge of the matrix resin, and the charge generated by surface friction is not enough to form an enhanced electrostatic repulsion, which in turn causes the attachment of most organic matter. In Example 1, due to the high electron attraction, enhanced surface polarity, defect structure, two-dimensional characteristics and stability of fluorinated graphene, the charge density in the triboelectric material can be significantly enhanced, and the strong electronegativity and electronic structure enable it to accumulate electrons more effectively during the friction process, thereby increasing the intensity of the triboelectric effect. In addition, the excellent stability of fluorinated graphene also ensures its charge accumulation ability and stability in long-term use. These characteristics give the coating surface an enhanced electrostatic repulsion effect, hindering the adhesion of organic substances to the coating surface, thereby achieving excellent antifouling performance.

[0036] The present invention also provides an application of the antifouling coating material based on the electrostatic repulsion effect, which is applied to marine equipment. The antifouling coating material with electrostatic repulsion effects forms a negative charge on the friction surface with seawater. The negative charge generates electrostatic repulsion with negatively charged fouling organic matter, thereby inhibiting the fouling organic matter from approaching the antifouling coating material with electrostatic repulsion effects, thereby inhibiting the adhesion of organic matter. In addition, the fluorinated graphene (FG) on the surface of the antifouling coating material itself is highly stable, non-toxic and harmless, and very environmentally friendly.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an antifouling coating material with electrostatic repulsion, characterized in that: The following steps are involved: S1: adding a certain amount of fluorinated graphene and tetraethylammonium chloride into a silicone resin, grinding and dispersing them uniformly to obtain a dispersed resin matrix; S2: adding dimethyl silica and silane coupling agent KH580 to the resin matrix obtained in step S1 and mixing them evenly to obtain an antifouling coating material.

2. The method for preparing the electrostatic repulsion antifouling coating material according to claim 1, characterized in that: The fluorinated graphene is prepared by using graphene oxide and trifluoromethanesulfonic acid as raw materials through a mild liquid phase reaction, and the preparation method comprises the following steps: S101: adding a certain amount of graphene oxide powder to a mixed solvent of methanol, ethanol and acetone, and stirring the mixture to promote dispersion; S102: placing the mixture in an ice water bath, adding trifluoromethanesulfonic acid dropwise three times, performing ultrasonic dispersion for 8 hours and then switching to magnetic stirring for 48 hours; S103: filtering the mixture, washing it with acetone and deionized water, and vacuum drying it to obtain fluorinated graphene.

3. The method for preparing the electrostatic repulsion antifouling coating material according to claim 1, characterized in that: In parts by weight, the amount of the organic silicone resin is 45 to 75 parts, the amount of the fluorinated graphene is 0.5 to 10 parts, the amount of tetraethylammonium chloride is 10 to 30 parts, the amount of dimethyl silica is 5 to 20 parts, and the amount of the silane coupling agent KH580 is 2 to 20 parts.

4. The method for preparing the electrostatic repulsion antifouling coating material according to claim 1, characterized in that: The grinding time in step S1 is 30 to 60 minutes, and the grinding speed is 400 to 800 rpm. The mixing time in step S2 is 5 to 30 minutes, and the mixing speed is 100 to 300 rpm.

5. The method for preparing the electrostatic repulsion antifouling coating material according to claim 2, characterized in that: In the step S103, the cleaning times are 3 times, the vacuum drying temperature is 60° C., and the vacuum drying time is 24 hours.

6. The method for preparing the electrostatic repulsion antifouling coating material according to claim 2, characterized in that: The amount of graphene oxide powder is 0.05-0.1 g, the amount of mixed solvent is 100-200 mL, the volume ratio of methanol, ethanol and acetone in the mixed solvent is 1:4:5, and the amount of trifluoromethanesulfonic acid is 1-2 mL.

7. Use of the electrostatic repulsion antifouling coating material prepared by the preparation method of the electrostatic repulsion antifouling coating material according to any one of claims 1 to 6, characterized in that: Applied to marine equipment, the electrostatic repulsion antifouling coating material forms negative charges on the friction surface with seawater, and the negative charges generate electrostatic repulsion with negatively charged fouling organic matter, thereby inhibiting the fouling organic matter from approaching the electrostatic repulsion antifouling coating material.

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