RU2733526C1 - Multifunctional additive to coatings - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to compositions of multifunctional nanostructured additives to coatings, such as lacquer, paint, enamel, in order to prevent corrosion processes and biofouling of underwater parts of ships and offshore structures. Multifunctional coating additive contains the following in wt. %: corrosion inhibitor and organic biocide in molar ratio 0.5–2.0/5.0–10.0, conducting polymer 10.0–40.0, copper or zinc nanoparticles 2.0–10.0, aluminosilicate nanotubes are the rest, up to 100. Aluminosilicate nanotubes are intercalated by a corrosion inhibitor and an organic biocide and coated with a layer of a conducting polymer with nanoparticles of copper or zinc on the surface of the polymer layer.

EFFECT: technical result consists in provision of intercalation of aluminosilicate nanotubes with corrosion inhibitor and organic biocide and coating of said nanotubes with layer of conducting polymer with nanoparticles of copper or zinc on surface.

1 cl, 2 tbl, 6 ex

Description

The invention relates to compositions of multifunctional nanostructured additives for coatings, such as varnishes, paints, enamels, in order to prevent corrosion and biofouling of underwater parts of ships and offshore structures.

Among the various anti-corrosion and anti-fouling technologies, coating is the most economical, practical and efficient method. Currently, coatings with either anti-fouling or anti-corrosion activity are common. Anti-fouling coatings are primarily based on the release of biocides into an aqueous environment. For example, from patents (CN 102634276 B, 2012, CN 106995621 A, 2017, RU2456360 C1, 2012) and literature (Railkin A.I. Colonization processes and protection against biofouling / A.I. Railkin. - St. Petersburg: Publishing house C .-Petersburg, Univ., 1998. - 272 p., Kudashov DV Microstructure Formations in Copper-Silicon Carbide Composites During Mechanical Alloying in a Planetary Activator / DV Kudashov, AA Aksenov, V. Klamm, U. Martin, H. Oettal , VK Portnoy, VS Zolotorevskii // Mat.-wiss. U. Werkstofftech. - 2000. - N 31. - P. 1048-1055) it is known to use metal oxides (zinc, copper) to prevent biofouling. Corrosion protection is not provided by such coatings or is provided to an insignificant extent. Anti-corrosion coatings of various compositions and modes of action also often perform one function.

In recent years, multifunctional coating additives have been developed to provide corrosion protection and partial biofouling protection. From the patent (CN 101643618 B, 2008), a technology is known for producing a non-toxic coating, including a modified polyaniline with partial antibacterial activity. The patent (CN 1073608 C, 1997) describes a composition having anticorrosive properties, including a conductive polyaniline, as well as copper oxide to inhibit biofouling. The patent (CN 108977007 A, 2018) describes the production of an anticorrosive powder coating containing titanium nitride and aniline polymerized on its surface, which has improved mechanical characteristics.

One of the high-tech ways to extend the service life of protective paints is the introduction of various kinds of capsules containing active ingredients. The use of inorganic capsules for loading antibacterial drugs is proposed in the patent (CN 105802293 B, 2016), where the capsules were used, among other things, to obtain anti-fouling coatings. In the publication Joshi, A; Abdullayev, E; Vasiliev, A; Volkova, O; Lvov, Y. Interfacial Modification of Clay Nanotubes for the Sustained Release of Corrosion Inhibitors dated 06/18/2013, LANGMUIR, volume: 29, issue: 24, pp.: 7439-7448 this approach was used to obtain additives for anti-corrosion coatings.

At the same time, the literature does not describe the use of aluminosilicate nanotubes intercalated with active components to create multifunctional additives to coatings with both anticorrosive and antifouling properties.

Essentially closest to the present invention is the coating additive described in Joshi, A; Abdullayev, E; Vasiliev, A; Volkova, O; Lvov, Y. Interfacial Modification of Clay Nanotubes for the Sustained Release of Corrosion Inhibitors 06/18/2013, LANGMUIR, volume: 29, issue: 24, pp.: 7439-7448. This article describes an additive to coatings based on aluminosilicate nanotubes and corrosion inhibitors such as benzotriazole, mercaptobenzothiazole and mercaptobenzimidazole. At the same time, a layer of a copolymer of urea and formaldehyde on the outer surface of the nanotubes prevents the rapid release of the corrosion inhibitor. To prepare the coating, the additive was mixed with oil alkyd paint in an amount of 5-10% of the mass.

The disadvantage of the described additive is the tendency to biofouling and incomplete corrosion protection of coatings obtained with its use.

The problem to be solved by the present invention is to provide a multifunctional additive for coatings with improved anti-corrosion and anti-fouling properties.

This problem is solved by creating a multifunctional additive to coatings, containing% of the mass:

- corrosion inhibitor and organic 5.0-10.0

biocide in a molar ratio of 0.5-2.0

- conductive polymer 10.0-40.0 - copper or zinc nanoparticles 2.0-10.0 - aluminosilicate nanotubes the rest, up to 100

in this case, aluminosilicate nanotubes are intercalated with a corrosion inhibitor and an organic biocide and coated with a conductive polymer layer with copper or zinc nanoparticles on the surface of the polymer layer.

The achieved technical result consists in providing intercalation of aluminosilicate nanotubes with a corrosion inhibitor and an organic biocyode and coating of these nanotubes with a layer of a conducting polymer with copper or zinc nanoparticles on the surface.

The described additive has an affinity for aqueous and organic media, is easily dispersible and can be used in all types of coatings.

Aluminosilicate nanotubes are natural or synthetic tubular aluminosilicates with a structure of multilayer or single-layer nanotubes. It is preferable to use natural mesoporous aluminosilicate nanotubes, for example, halloysite with an outer diameter of 30-60 nm, an inner diameter of 20-40 nm and a length of 400 nm - 2 μm.

The described multifunctional nanostructured additive to coatings is prepared as follows.

Saturated solutions of a corrosion inhibitor and an organic biocide are prepared in a solvent, for example, ethanol, acetone. Compounds such as, for example, benzotriazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole can be used as a corrosion inhibitor. As an organic biocide, for example, dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), pyridine-triphenylborane, medetomidine can be used.

Saturated solutions of corrosion inhibitor and organic biocide are added to aluminosilicate nanotubes, while the molar ratio of corrosion inhibitor / organic biocide is 0.5-2.0. The mixture is dispersed until homogenized and placed in a vacuum atmosphere for degassing and intercalation of aluminosilicate nanotubes with a corrosion inhibitor and an organic biocide. To remove excess corrosion inhibitor and organic biocide, the precipitate is separated, washed with a solvent and dried at a temperature of 60-90 ° C for 2-12 hours.

The obtained aluminosilicate nanotubes intercalated with a corrosion inhibitor and an organic biocide are coated with a layer of a conducting polymer as follows: monomers of conducting polymers (pyrrole, aniline, thiophene) are added to the dispersion of intercalated aluminosilicate nanotubes in a solvent (water) in such an amount that the mass of the conducting polymer is 10- 40% by weight of the finished multifunctional nanostructured additive. The mixture is stirred for 1-2 hours. The polymerization reaction is carried out with vigorous stirring for 3-24 hours in an acidic medium with the addition of an oxidizing agent, for example, ammonium persulfate. The resulting precipitate is separated, washed and dried for 3-24 hours at a temperature of 60-100 ° C. The result is aluminosilicate nanotubes intercalated with a corrosion inhibitor and an organic biocide and coated with a conductive polymer layer.

Copper or zinc nanoparticles are applied to the material obtained above. To do this, mix a dispersion of aluminosilicate nanotubes coated with a layer of a conducting polymer, intercalated with a corrosion inhibitor and an organic biocide, with a solution (in water) of a metal salt (copper or zinc), in such a ratio that, as a result, the finished additive contains metal in an amount of 2.0-10 , 0% of the mass. The mixture is stirred for 0.5-3 hours. Then a reducing agent (sodium borohydride, hydrazine) is added to the mixture, and the salt reduction reaction is carried out to form metal nanoparticles. The resulting precipitate is separated, washed with a solvent (water) and dried for 24-48 hours at 60-100 ° C. At the same time, a targeted multifunctional additive is obtained.

To prepare coatings that prevent corrosion and biofouling, the proposed additive is introduced into the coating base in an amount of 5-20% of the coating weight.

Examples are presented below to illustrate the invention but not limit it.

Example 1

A saturated solution of benzotriazole in acetone is added to aluminosilicate nanotubes (halloysite). The resulting mixture is dispersed for 30 minutes and degassed under vacuum at 0.1 MPa for 30 minutes to intercalate the nanotubes with a corrosion inhibitor. To remove excess benzotriazole, the mixture is centrifuged and washed with acetone and dried at 60 ° C for 6 hours. Dried aluminosilicate nanotubes intercalated with benzotriazole are ground to a fine powder. The obtained aluminosilicate nanotubes are dispersed in water and aniline is added in the calculation of 15% of the mass. from nanotubes. The resulting mixture is stirred for 30 minutes. Next, ammonium persulfate, previously dissolved in 100.0 ml of distilled water, in an amount of 227% by weight of aniline, and phosphoric acid in a weight ratio with ammonium persulfate 1: 5, are added to the mixture dropwise over 30 minutes. The polymerization reaction is carried out with stirring for 3 hours. After stirring, the resulting precipitate is centrifuged and washed with distilled water. Dry for 12 hours at 80 ° C.

Copper nanoparticles are applied to the obtained carrier in an amount of 10.0% by weight, based on the weight of the finished additive as follows: the carrier obtained earlier is mixed with distilled water in a weight ratio of 1:25 and stirred for 30 minutes. A solution of copper chloride in distilled water of the calculated concentration is added to the resulting suspension and stirred for 1 hour. Then sodium borohydride is added dropwise until the salt is completely reduced, with the formation of copper nanoparticles on the surface of the carrier. The resulting precipitate is separated, washed with distilled water and dried for 24 hours at 80 ° C. As a result, a multifunctional additive to coatings is obtained containing benzotriazole 10.0% by weight, polyaniline 10.0% by weight, copper 10.0% by weight, aluminosilicate nanotubes 70.0% by weight. In this case, aluminosilicate nanotubes are intercalated with benzotriazole and coated with a polyaniline layer. Copper is deposited in the form of nanoparticles on the surface of the polymer layer.

Example 2

A saturated solution of dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) in ethanol is added to aluminosilicate nanotubes (halloysite). The resulting mixture is dispersed for 30 minutes and degassed under vacuum at 0.1 MPa for 30 minutes to intercalate the nanotubes with an organic biocide. To remove excess dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), the mixture is centrifuged and washed with ethanol. After washing, the aluminosilicate nanotubes are dried at 60 ° C for 12 hours. Dried aluminosilicate nanotubes intercalated with dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) are ground to a fine powder. The obtained aluminosilicate nanotubes are dispersed in water and 66% of the mass is added. aniline based on the weight of aluminosilicate nanotubes. The resulting mixture is stirred for 30 minutes. Next, ammonium persulfate, previously dissolved in 100.0 ml of distilled water, in an amount of 340.0% of the mass, is added dropwise to the prepared mixture within 30 minutes. from the mass of aniline, and phosphoric acid in a mass ratio with ammonium persulfate 1: 5. The polymerization reaction is carried out with stirring for 3 hours. During polymerization, the color changes to dark green. After stirring, the resulting precipitate is centrifuged and washed with distilled water. Dry for 18 hours at 80 ° C.

Zinc nanoparticles are applied to the obtained carrier in an amount of 2.0% of the weight of the finished additive as follows: the carrier obtained earlier is mixed with distilled water in a weight ratio of 1:25 and stirred for 30 minutes. A solution of zinc chloride in distilled water of the calculated concentration is added to the resulting suspension and stirred for 1 hour. Then hydrazine hydrate is added dropwise until the salt is completely reduced, with the formation of zinc nanoparticles on the surface of the carrier. The resulting precipitate is separated, washed with distilled water and dried for 24 hours at 80 ° C. As a result, a multifunctional additive to coatings is obtained containing dichloroctylisothiazolinone 10.0 wt%, polyaniline 40.0 wt%, zinc 2.0 wt%, aluminosilicate nanotubes 48.0 wt%. In this case, aluminosilicate nanotubes are intercalated with dichloroctylisothiazolinone and coated with a polyaniline layer. Zinc is deposited in the form of nanoparticles on the surface of the polymer layer.

Example 3

Saturated solutions of benzotriazole and dichloroctylisothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) in acetone in a benzotriazole / dichloroctylisothiazolinone molar ratio of 0.5: 1 are added to aluminosilicate nanotubes (halloysite). The resulting mixture is dispersed for 30 minutes and degassed under vacuum at 0.1 MPa for 30 minutes to intercalate the nanotubes with a corrosion inhibitor and an organic biocide. To remove excess benzotriazole and dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), the mixture is centrifuged and washed with acetone. After washing, the aluminosilicate nanotubes are dried at 60 ° C for 12 hours. Dried aluminosilicate nanotubes intercalated with benzotriazole and dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) are ground to a fine powder. The obtained aluminosilicate nanotubes are dispersed in water and 15% of the mass is added. aniline based on the weight of aluminosilicate nanotubes. The resulting mixture is stirred for 30 minutes. Next, ammonium persulfate in an amount of 277.0% of the mass, previously dissolved in 100.0 ml of distilled water, is added dropwise to the prepared mixture within 30 minutes. from the mass of aniline, and phosphoric acid in a mass ratio with ammonium persulfate 1: 5. The polymerization reaction is carried out with stirring for 3 hours. During polymerization, the color changes to dark green. After stirring, the resulting precipitate is centrifuged and washed with distilled water. Dry for 18 hours at 80 ° C.

Copper nanoparticles are applied to the obtained support in an amount of 10.0% of the weight of the finished additive as follows: the previously obtained support is mixed with distilled water in a weight ratio of 1:25 and stirred for 30 minutes. A solution of copper chloride in distilled water of the calculated concentration is added to the resulting suspension and stirred for 1 hour. Then sodium borohydride is added dropwise until the salt is completely reduced, with the formation of copper nanoparticles on the surface of the carrier. The resulting precipitate is separated, washed with distilled water and dried for 24 hours at 80 ° C. As a result, a multifunctional additive to coatings is obtained, containing benzotriazole and dichloroctylisothiazolinone in a molar ratio of 0.5 to 10.0 wt%, polyaniline 10.0 wt%, copper 10.0 wt%, aluminosilicate nanotubes 70.0 wt%. In this case, aluminosilicate nanotubes are intercalated with benzotriazole and dichloroctyl isothiazolinone and coated with a polyaniline layer. Copper is deposited in the form of nanoparticles on the surface of the polymer layer.

Example 4

Saturated solutions of benzotriazole and dichloroctylisothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) in acetone in a benzotriazole / dichloroctylisothiazolinone molar ratio of 1: 1 are added to aluminosilicate nanotubes (halloysite). The resulting mixture is dispersed for 30 minutes and degassed under vacuum at 0.1 MPa for 30 minutes to intercalate the corrosion inhibitor and organic biocide into nanotubes. To remove excess benzotriazole and dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), the mixture is centrifuged and washed with acetone. After washing, the aluminosilicate nanotubes (halloysite) are dried at 60 ° C for 12 hours. Dried aluminosilicate nanotubes intercalated with benzotriazole and dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) are ground to a fine powder. The obtained aluminosilicate nanotubes are dispersed in water and 15% of the mass is added. pyrrole per weight of aluminosilicate nanotubes. The resulting mixture is stirred for 30 minutes. Next, ammonium persulfate, previously dissolved in 100.0 ml of distilled water, in an amount of 277.0% of the mass, is added dropwise to the prepared mixture over 30 minutes. from the mass of pyrrole and phosphoric acid in a mass ratio with ammonium persulfate 1: 5. The polymerization reaction is carried out with stirring for 3 hours. After stirring, the resulting precipitate is centrifuged and washed with distilled water. Dry for 18 hours at 80 ° C.

Zinc nanoparticles are applied to the obtained carrier in an amount of 2.0% of the weight of the finished additive as follows: the carrier obtained earlier is mixed with distilled water in a weight ratio of 1:25 and stirred for 30 minutes. A solution of zinc chloride in distilled water of the calculated concentration is added to the resulting suspension and stirred for 1 hour. Then hydrazine hydrate is added dropwise until the salt is completely reduced, with the formation of zinc nanoparticles on the surface of the carrier. The resulting precipitate is separated, washed with distilled water and dried for 24 hours at 80 ° C. As a result, a multifunctional additive to coatings is obtained containing benzotriazole and dichloroctylisothiazolinone in a molar ratio of 1 5.0 wt%, polyaniline 10.0 wt%, zinc 2.0 wt%, aluminosilicate nanotubes 83.0 wt%. In this case, aluminosilicate nanotubes are intercalated with benzotriazole and dichloroctylisothiazolinone and covered with a polypyrrole layer. Zinc is deposited in the form of nanoparticles on the surface of the polymer layer.

Example 5

Saturated solutions of benzotriazole and dichloroctylisothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) in acetone in a benzotriazole / dichloroctylisothiazolinone molar ratio of 0.5: 1 are added to aluminosilicate nanotubes (halloysite). The resulting mixture is dispersed for 30 minutes and degassed under vacuum at 0.1 MPa for 30 minutes to intercalate the corrosion inhibitor and organic biocide into nanotubes. To remove excess benzotriazole and dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), the mixture is centrifuged and washed with acetone. After washing, the aluminosilicate nanotubes are dried at 60 ° C for 12 hours. Dried aluminosilicate nanotubes intercalated with benzotriazole and dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) are ground to a fine powder. The obtained aluminosilicate nanotubes are dispersed in water and 66% of the mass is added. aniline based on the weight of aluminosilicate nanotubes. The resulting mixture is stirred for 30 minutes. Next, ammonium persulfate, previously dissolved in 100.0 ml of distilled water, in an amount of 340.0% of the mass, is added dropwise to the prepared mixture within 30 minutes. from the mass of aniline, and phosphoric acid in a mass ratio with ammonium persulfate 1: 5. The polymerization reaction is carried out with stirring for 3 hours. During polymerization, the color changes to dark green. After stirring, the resulting precipitate is centrifuged and washed with distilled water. Dry for 18 hours at 80 ° C.

On the obtained carrier, zinc is applied in an amount of 10.0% of the weight of the finished additive as follows: the carrier obtained earlier is mixed with distilled water in a weight ratio of 1:25 and stirred for 30 minutes. A solution of zinc chloride in distilled water of the calculated concentration is added to the resulting suspension and stirred for 1 hour. Then sodium borohydride is added dropwise until the salt is completely reduced, with the formation of zinc nanoparticles on the surface of the carrier. The resulting precipitate is separated, washed with distilled water and dried for 24 hours at 80 ° C. As a result, a multifunctional additive to coatings is obtained containing benzotriazole and dichloroctylisothiazolinone in a molar ratio of 0.5 to 10.0 wt%, polyaniline 40.0 wt%, zinc 10.0 wt%, aluminosilicate nanotubes 40.0 wt%. In this case, aluminosilicate nanotubes are intercalated with benzotriazole and dichloroctyl isothiazolinone and coated with a polyaniline layer. Zinc is deposited in the form of nanoparticles on the surface of the polymer layer.

Example 6

Saturated solutions of benzotriazole and dichloroctylisothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) in acetone in a benzotriazole / dichloroctylisothiazolinone molar ratio of 2: 1 are added to aluminosilicate nanotubes (halloysite). The resulting mixture is dispersed for 30 minutes and degassed under vacuum at 0.1 MPa for 30 minutes to intercalate the corrosion inhibitor and organic biocide into nanotubes. To remove excess benzotriazole and dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one), the mixture is centrifuged and washed with acetone. After washing, the aluminosilicate nanotubes are dried at 60 ° C for 12 hours. Dried aluminosilicate nanotubes intercalated with benzotriazole and dichloroctyl isothiazolinone (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) are ground to a fine powder. The obtained aluminosilicate nanotubes are dispersed in water and 66% by weight of aniline is added, based on the weight of aluminosilicate nanotubes. The resulting mixture is stirred for 30 minutes. Next, ammonium persulfate, previously dissolved in 100.0 ml of distilled water, in an amount of 340.0% of the mass, is added dropwise to the prepared mixture within 30 minutes. from the mass of aniline, and phosphoric acid in a mass ratio with ammonium persulfate 1: 5. The polymerization reaction is carried out with stirring for 3 hours. During polymerization, the color changes to dark green. After stirring, the resulting precipitate is centrifuged and washed with distilled water. Dry for 18 hours at 80 ° C.

Copper nanoparticles are applied to the obtained support in an amount of 2.0% of the weight of the finished additive as follows: the previously obtained support is mixed with distilled water in a weight ratio of 1:25 and stirred for 30 minutes. A solution of copper chloride in distilled water of the calculated concentration is added to the resulting suspension and stirred for 1 hour. Then sodium borohydride is added dropwise until the salt is completely reduced, with the formation of copper nanoparticles on the surface of the carrier. The resulting precipitate is separated, washed with distilled water and dried for 24 hours at 80 ° C. As a result, a multifunctional additive to coatings is obtained, containing benzotriazole and dichloroctylisothiazolinone in a molar ratio of 2 10.0 wt%, polyaniline 40.0 wt%, copper 2.0 wt%, aluminosilicate nanotubes 48.0 wt%. In this case, aluminosilicate nanotubes are intercalated with benzotriazole and dichloroctyl isothiazolinone and coated with a polyaniline layer. Copper is deposited in the form of nanoparticles on the surface of the polymer layer.

Table 1 shows the composition of a multifunctional nanostructured additive for preventing corrosion and biofouling processes obtained in examples 1-6.

The additives obtained in examples 0-6 are used to prepare coatings to prevent corrosion and biofouling. The coatings are prepared as follows. The additive obtained according to examples 0-6 is introduced into the epoxy resin in an amount of 5% by weight of the coating. The mixture is homogenized and a hardener is added in an amount of 12% by weight of the coating, and again homogenized. The resulting mixture is applied to a metal surface and left at room temperature until completely dry.

The finished coated metal surfaces are tested for corrosion and biofouling resistance. For this, the coating is mechanically damaged and the test is carried out in the natural conditions of the southern sea for 5 months in a warm period at a depth of 3 meters. The data on the composition of the coatings and the results of the studies carried out are presented in Table 2.

From the above table it follows that the use of additives of the proposed composition (additives according to examples 3-6) can give the coatings improved antifouling and anticorrosive properties in comparison with the known additive, as well as in comparison with the additives obtained in examples 1-2. When using additives according to examples 3-6, traces of biofouling were not found both on the intact surface of the coating and in the place of mechanical damage. No visible corrosion was observed with the additives prepared in Examples 3-6. The use of the described multifunctional additive containing components in other concentrations included in the stated range leads to similar results. The use of components in quantities outside this range does not lead to the desired results.

Thus, the described multifunctional nanostructured additive has improved anticorrosive and antifouling properties.

Claims (5)

Multifunctional additive to coatings containing% wt .: - corrosion inhibitor and organic 5.0-10.0 biocide in a molar ratio of 0.5-2.0 - conductive polymer 10.0-40.0 - copper or zinc nanoparticles 2.0-10.0 - aluminosilicate nanotubes the rest, up to 100 in this case, aluminosilicate nanotubes are intercalated with a corrosion inhibitor and an organic biocide and coated with a conductive polymer layer with copper or zinc nanoparticles on the surface of the polymer layer.