COATING COMPOSITIONS AND METHODS FOR PREVENTING THE FORMATION

OF BIOFILMS ON SURFACES

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims benefit of US provisional application 62/546305 filed 16 August 2017, the entire content of which is incorporated herein by reference. FIELD OF THE DISCLOSURE

[0002] The present disclosure generally relates to anti- biofilm sol-gel films. More particularly, the invention relates to ORMOSIL (organically modified silica) anti-biofilms coatings.

BACKGROUND OF THE DISCLOSURE

[0003] Biological fouling (biofouling) of man-made underwater structures has been a significant problem. For instance, material deterioration, losses in heat transfer efficiency, mechanical blockages of fluids transport and increase fuel consumption for vessels are all problems resulting from biofouling .

[0004] Most of the times, microorganisms biofilms are the root cause of biofouling. Microorganisms (also known as microbes) are microscopic organism that are single-celled or multicellular. Microorganisms are very diverse and include bacteria, archaea, protozoa and also some fungi, some algae and some micro-animals. [0005 ] Microbial growth on surface is a serious problem. Underwater surfaces, like boat hull, are rapidly colonized by microorganisms (e.g. diatoms, bacteria) forming a biofilm layer in the first stage of marine biofouling. A biofilm (also called the slime) is an agglomeration of microorganisms on a surface that is surrounded or held together by an organic matrix of extracellular polymeric substances. After about one week under water, the biofilm found on an untreated immersed surface is rich in nutrients. At this point, secondary and tertiary macrofoulers (e.g. algae, tube worms, mussels, barnacles) can easily attach to the biofilm.

SUMMARY OF THE DISCLOSURE

[0006 ] The present disclosure provides a combination of silanes, a sol-gel matrix obtained from said silanes, a mixture of said sol-gel matrix and antifouling compounds, as well as surface coating compositions (also referred to as ORMOSIL films) comprising said combination of silanes or sol- gel matrix and optionally said antifouling compounds that can be used to generate a xerogel film.

[0007 ] The present disclosure also provides methods to reduce or prevent biofilm formation on a surface, comprising applying on said surface, prior to said biofilm formation, a combination of silanes, a sol-gel matrix obtained from said silanes, a mixture of said sol-gel matrix and antifouling compound, as well as surface coating compositions comprising said combination of silanes or sol-gel matrix as defined herein . [0008 ] In an aspect, the present disclosure provides surface coatings prepared from a combination of silanes, a sol-gel matrix obtained from said silanes, a mixture of said sol-gel matrix and antifouling compounds, as well as surface coating compositions .

BRIEF DESCRIPTION OF THE FIGURES

[0009] Fig. 1 shows the bacterial evolution in aquarium water using the flux cytometry methodology.

DETAILED DESCRIPTION

[0010 ] The present disclosure relates to a combination of silanes, a sol-gel matrix obtained from said silanes, optionally an antifouling compound, as well as anti-biofilm coating compositions comprising said combination of silanes or sol-gel matrix and said optional antifouling additives, that can be used to generate a xerogel film.

[0011] The present disclosure provides methods for reducing or preventing biofilm formation on surfaces comprising applying, prior to formation of said biofilm, the combination of silanes, the sol-gel matrix, and optionally antifouling compound, composition or coating described herein, on said surfaces .

[0012 ] The organically-modified, hybrid xerogel coatings of the present disclosure are used in methods for reducing or preventing biofilm formation by microorganisms on surfaces with which they come in contact. The xerogel surfaces are inexpensive and the alkyl silane are essential in the mixture to form a crackles, smooth, defect free surface with desirable hydrophobicity and roughness/topography. The hydrophobicity of the xerogel surface (i.e. hydrophobic surface) provides fouling release properties.

[0001 ] As used herein, a xerogel is a solid formed from a sol-gel matrix by drying with unhindered shrinkage. Compared to usual silica gel solids obtained by the sol-gel method, a xerogel film has a lower surface area. (150m ² /g instead of 800-900m ² /g) with very small pore size (lower than 2 nm) . Also, silica xerogel films (and ORMOSIL films) are not free flowing solids (small solid particles) like silica gels comprising distinct particles . Silica xerogel films form a continuous three-dimensional cross-linked network consisting of Si-O-Si units on the treated surface.

[0002 ] Alkyl group as used herein, unless otherwise expressly stated, refers to branched or unbranched saturated hydrocarbons. Examples of alkyl groups include methyl groups, ethyl groups, n-propyl groups, i-propyl groups, n-butyl groups, i-butyl groups, s-butyl groups, pentyl groups, hexyl groups, octyl groups, nonyl groups, and decyl groups and octadecyl groups. The alkyl group can be unsubstituted or substituted with groups such as halides (-F, -CI, -Br, and - I), alkenes, alkynes, aliphatic groups, aryl groups, alkoxides, carboxylates , carboxylic acids, and ether groups. For example, the alkyl group can be perfluorinated . [0003 ] Alkoxy group as used herein, unless otherwise expressly stated, refers to -OR groups, where R is an alkyl group as defined herein. Examples of alkyoxy groups include methoxy groups, ethoxy groups, n-propoxy groups, i-propoxy groups, n-butoxy groups, i-butoxy groups, and s-butoxy groups.

[0004 ] As used herein, a sol-gel matrix is comprising two or more silanes, some of which having been partially hydrolyzed

(i.e. some of the alkoxy groups on the silanes having been hydrolyzed to hydroxyl groups), and/or condensed (i.e. at least some of the Si-OH have Si-O-Si bonds), therefore leading to small oligomers comprising siloxane groups derived from the partially hydrolyzed silanes .

[0005 ] Preferably, the sol-gel matrix is obtained from mixing a combination of silanes, and a catalyst for partially hydrolyzing alkoxy groups on the silanes. In one embodiment, the catalyst is an acid, such as an aqueous acid.

[0006 ] As used herein, a composition is comprising a combination of silanes or a sol-gel matrix as defined herein and an organic solvent. A composition may be comprising an organic solvent.

[0007 ] Preferably, the solvent is a water miscible solvent In one embodiment, the solvent is an alcohol or a mixture o alcohols. Non-limiting examples include methanol, ethanol isopropanol or mixtures thereof .

[0008 ] In one embodiment, the composition as defined herein is prepared by mixing a combination of silanes, and a catalyst for partially hydrolyzing alkoxy groups on the silanes, wherein said catalyst is an aqueous acid in admixture with a water miscible solvent.

[0009] In one embodiment, the molar amount of catalyst for partially hydrolyzing alkoxy groups is from about 0,001 mol% to about 10 mol% .

[0010 ] In one embodiment, one or more antifouling compounds are added to the composition or in the sol-gel matrix precursors, either by solubilisation or by suspension in the composition or in the sol-gel matrix precursors.

[0011] In one embodiment, the molar amount of the antifouling compound is from about 0,0001 mol% to about 60 mol% .

[0012 ] Antifouling compound as used herein, unless otherwise expressly stated, refer to any agent that prevent biofouling. Examples of antifouling compounds include metal-based compounds such as copper, copper thiocyanate, dicopper oxide, Zineb™ (zinc ethane-1, 2-diylbis (dithiocarbamate) , copper pyrithione, zinc oxide, zinc pyrithione (bis (2- pyridylthio ) zinc 1 , 1 ' -dioxide ) , Ti02, and silver as well as organic-based compounds such as Tolylfluanid (N-

[dichloro ( fluoro ) methyl ] sulfanyl-N- (dimethylsulfamoyl ) -4- methylaniline ) , Tralopyril ( 4-bromo-2- ( 4-chlorophenyl ) -5-

(trifluoromethyl ) -lH-pyrrole-3-carbonitrile ) , Medetomidine (4-

(1- (2, 3-Dimethylphenyl) ethyl) -lH-imidazole) , EconeaTM (4- Bromo-2- ( 4-chlorphenyl ) -5- (trifluormethyl) -lH-pyrrol-3- carbonitril ) , Irgarol™ (2-methylthio-4-tert-butylamino cyclopylamino-6- (1, 3, 5-triazine) ) and , 5-Dichloro-2-octyl-4- isothiazolin-3-one (DCOIT) .

[0013] The amount of antifouling compound can be adapted by the skilled person based on the composition used. For example, a copper-based antifouling compound may be used in a range of 0.01% to 60% (mass basis), or 0.1% to 30%, or 20% to 30%. As a further example, copper pyrithion may be present in an amount of 0.01% to 10%, or 0.1% to 5%, or about 1%.

[0014] Methods for reducing or preventing biofilm formation as used herein, unless otherwise expressly stated, refer to one or more of the following : reducing or eliminating biofilms growth, reducing the biofilm thickness, reducing cellular activity in the biofilm, reducing the amount of surface cover by the biofilm, reducing the viability of microorganisms in the biofilm, reducing the biodiversity in the biofilm, reducing the ability of the biofilm to adhere or bond on surfaces or killing (partially or completely) microorganism that come in contact with the surface.

[0015] Biofilm, as used herein, unless otherwise expressly stated, refer to any agglomeration of microorganism adherent on a surface. Frequently, these adherent microorganisms are surrounded or held together by an organic matrix of extracellular polymeric substances . Biofilms may form on living or non-living surfaces . Biofilms can contain many different types of microorganism but some organisms can form single-species films under the right conditions. In one embodiment, the biofilm is a marine biofilm (i.e. grown in an aqueous environment) . The marine biofilm may be one growing as the natural diversity of the usual marine microbial organisms . The biofilm, may be microbiofouling composed of multispecies bacteria in natural growth condition.

[0016 ] Examples of microorganisms include Vibrio splendidus, Pseudoalteromonas haloplanktis, Shewanella colwelliana, Roseobacter denitrificans and Planococcus kocurii.

[0017 ] The xerogel materials have tunable surface hydrophobicity, surface energies and fouling release proprieties (by selection of appropriate sol-gel alkyl silane precursors) and are thinner (10-30 μπι) with higher elastic modulus than silicone films. The appropriate alkyl silane precursor will generate a smooth surface devoid of cracks and imperfection, with a good adherence on substrate. When two or more layers of coating are applied, the thickness will proportionally increase (e.g. 20-60μιη for 2 layers, etc.) .

[0018 ] Hydrophobic surface (or hydrophobicity) as used herein, otherwise expressly stated, refers to surface that present a static water contact angle greater than 85 degrees as measured by the sessile drop technique where the angle between a 15 μΐ, drop of water and the surface is measured with a contact angle goniometer.

[0019 ] In accordance with this disclosure, an example of a xerogel surface is incorporating 1 mole % of an n- octadecyltrimethoxysilane (C18) precursor in combination with 0.1 mole % of an organo-functional ammonium- chloridetrimethoxysilane (SiOAC) and with an n- octyltriethoxysilane (C8) and tetraethoxysilane (TEOS) . [0020 ] In accordance with this disclosure, an example of a xerogel surface is incorporating 1 mole % of an n- octadecyltrimethoxysilane (C18) precursor in combination with 49 mole % of an n-octyltriethoxysilane (C8) and tetraethoxysilane (TEOS).

[0021] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from 1 mole % of an organo-functional ammonium-chloridetrimethoxysilane (SiOAC) with an n-octyltriethoxysilane (C8) and tetraethoxysilane

(TEOS) .

[0022 ] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from 0.1 mole % of an organo-functional ammonium-chloridetrimethoxysilane (SiOAC) with an n-octyltriethoxysilane (C8) and tetraethoxysilane

(TEOS) .

[0023] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from 0.1 mole % of an organo-functional ammonium-chloridetrimethoxysilane (SiOAC) with an n-propyltriethoxysilane (C3) and tetraethoxysilane

(TEOS) .

[0024] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from 0.1 mole % of an organo-functional ammonium-chloridetrimethoxysilane (SiOAC) with an n-octyltriethoxysilane (C8) and tetraethoxysilane

(TEOS) with an addition of 0.1 % mass of copper (I) oxide

(Cu ₂ 0) . [0025 ] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from an n- octyltriethoxysilane (C8) and tetraethoxysilane (TEOS) with an addition of 0.1 % mass of copper (I) oxide (Cu ₂ 0) .

[0026 ] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from an n- octyltriethoxysilane (C8) and tetraethoxysilane (TEOS) with an addition of 30 % mass of copper (I) oxide (CU ₂ O) .

[0027 ] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from an n- octyltriethoxysilane (C8) and tetraethoxysilane (TEOS) with an addition of 30 % mass of copper (I) oxide (Cu ₂ 0) and an addition of 20 % mass of zinc oxide (ZnO) .

[0028 ] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from:

said long-chain alkyltrialkoxysilane, said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

said long-chain alkyltrialkoxysilane, said perfluoroalkyltrialkoxysilane and said tetraalkoxysilane;

said quaternary ammonium silane, said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

said quaternary ammonium silane, said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

said short-chain amino-alkyltrialkoxysilane , said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

Cu ₂ 0, said short-chain alkyltrialkoxysilane, and said tetraalkoxysilane; Cu ₂ 0 and ZnO, said short-chain alkyltrialkoxysilane, and said tetraalkoxysilane;

CU2O , said quaternary ammonium silane, said short- chain alkyltrialkoxysilane and said tetraalkoxysilane;

copper thiocyanate; said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

zinc pyrithione; said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

Ti0 ₂ ; said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

zineb; said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

CU2O or T1O2 ; zineb; said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

econea; said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

CU2O or T1O2 ; econea; said short-chain alkyltrialkoxysilane and said tetraalkoxysilane;

for any of the above, said alkyltrialkoxysilane is C3 alkyltri (C1-C3 ) alkoxysilane or C ₈ alkyltri (C1-C3 ) alkoxysilane (such as n-propyltriethoxysilane and n-octyltriethoxysilane ) ; said long-chain alkyltrialkoxysilane is C18alkyltri (Cl- C3 ) alkoxysilane (such as n-octadecyltriethoxysilane ) ; said quaternary ammonium silane has the formula ( RO ) ₃ Si-Z-N ⁺ R ² R ³ R ⁴ X ^~ , wherein R is C1-C3 alkyl, Z is C3 alkylene, R2-R3 are C1-C2 alkyl and R4 is Cl-C18alkyl or CH ₂ C ₆ H ₅ and X is CI or Br 'such as octadecyldimethyl (3-trimethoxysilylpropyl ) -ammonium chloride); and said tetraalkoxysilane is tetra (Cl- C ) alkoxysilane such as tetraethoxysilane ) [0029 ] In accordance with this disclosure, other examples of xerogel surfaces include xerogels prepared from:

about 1 mole % of said long-chain alkyltrialkoxysilane , about 49 mole % of said short-chain alkyltrialkoxysilane and about 49 mole % of said tetraalkoxysilane;

about 10 mole % of said long-chain alkyltrialkoxysilane, about 40 mole % of said perfluoroalkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 1 mole % of said quaternary ammonium silane, about 49 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 0.1 mole % of said quaternary ammonium silane, about 49.9 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 0.1 mole % of said short-chain amino- alkyltrialkoxysilane, about 49.9 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 0.1 to about 30% mass of Cu ₂ 0 (such as 0.1% or 1% or 5% or 10% or 20% or 30%), about 50 mole % of said short- chain alkyltrialkoxysilane, and about 50 mole % of said tetraalkoxysilane;

about 20 to about 30% mass of each of Cu ₂ 0 and ZnO, about 50 mole % of said short-chain alkyltrialkoxysilane, and about 50 mole % of said tetraalkoxysilane;

about 0.1 to about 10 mass % of Cu ₂ 0, about 0.1 to about 1 mol % of said quaternary ammonium silane, about 49 to about 49.9 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane; about 1% to about 5% mass of copper thiocyanate; about 50 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 1% to about 5% mass of zinc pyrithione; about 50 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 10% to about 20% mass of Ti0 ₂ ; about 50 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 1% mass of zineb; about 50 mole % of said short- chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 10% mass of CU ₂ O or TiC^; about 0,1% mass of zineb; about 50 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 1% mass of econea; about 50 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

about 10% mass of Cu ₂ 0 or Ti0 ₂ ; about 0,1% mass of econea; about 50 mole % of said short-chain alkyltrialkoxysilane and about 50 mole % of said tetraalkoxysilane;

for any of the above, said alkyltrialkoxysilane is C3 alkyltri (C1-C3 ) alkoxysilane or C ₈ alkyltri (C1-C3 ) alkoxysilane (such as n-propyltriethoxysilane and n-octyltriethoxysilane ) ; said long-chain alkyltrialkoxysilane is C18alkyltri (Cl- C3 ) alkoxysilane (such as n-octadecyltriethoxysilane ) ; said quaternary ammonium silane has the formula ( RO ) ₃ Si-Z-N ⁺ R ² R ³ R ⁴ X ^~ , wherein R is C1-C3 alkyl, Z is C3 alkylene, R2-R3 are C1-C2 alkyl and R4 is Cl-C18alkyl or CH ₂ C ₆ H ₅ and X is CI or Br 'such as octadecyldimethyl (3-trimethoxysilylpropyl ) -ammonium chloride); and said tetraalkoxysilane is tetra (Cl- C ) alkoxysilane such as tetraethoxysilane) .

[0030 ] The xerogel surfaces are preferably optically transparent but pigments additives can be added to the sol-gel matrix to generate a colored xerogel without loss of antifouling activity.

[0031] The xerogel require no "tie" coat, such as an adhesive or an adhesive made of double-sided sticky sheets, for bonding to a variety of surface.

[0032 ] In one embodiment, there is provided methods for reducing biofilms growth by killing (partially or completely) microorganism that come in contact with the surface, comprising providing a xerogel film as defined herein, on at least a portion of said surface.

[0033] In one embodiment, the xerogel is obtained by applying the sol-gel matrix or the composition as defined herein in a non-solid form (e.g. liquid or gel form), and as such the method does not require any crushing or other manipulation of a solid to coat the surface of an object for which reducing biofilms growth is desired.

[0034] In one embodiment, the method is comprising providing a xerogel on at least a portion of a surface that can be subjected to biofilm growth, wherein said xerogel is obtained by applying the composition as defined herein on said surface, and wherein said composition is comprising two or more silanes, some of which having been partially hydrolyzed and/or condensed, and said composition further comprising a water miscible organic solvent.

[0035 ] The present disclosure uses a sol-gel matrix or a composition comprising same for coating a surface. The xerogel film is formed from the sol-gel obtained from hydrophobic silanes (alkyl silane).

[0036 ] Antifouling compounds can be incorporated as additives in the xerogel by dissolution or suspension in the sol-gel.

[0037 ] Pigments, markers, emulsifiers and thickeners can be incorporated as additives in the xerogel by dissolution or suspension in the sol-gel.

[0038 ] The surface coatings are used in methods for reducing or preventing biofilms formation on surfaces .

[0039 ] The coatings are preferably obtained from a multi- component ORMOSIL (organically modified silica) xerogel films (also referred to herein as hybrid films) . The xerogel films can be formed by sol-gel methods, such as disclosed herein.

[0040 ] In an embodiment, a biofilm growth reducing surface coating composition comprises a sol-gel matrix. The composition comprises two, three or more partially hydrolyzed and/or condensed silanes. In another embodiment, the biofilms growth reducing coating consists essentially of a sol-gel matrix and the composition consists essentially of partially hydrolyzed and/or condensed silanes. In another embodiment, the biofilms growth reducing coating consists essentially of a sol-gel matrix and the composition consists essentially of three partially hydrolyzed and/or condensed silanes. In another embodiment, the biofilms growth reducing coating consists essentially of a sol-gel matrix and the composition consists essentially of four partially hydrolyzed and/or condensed silanes. In yet another embodiment, the biofilms growth reducing coating consists of a sol-gel matrix and the composition consists of two partially hydrolyzed and/or condensed silanes. In yet another embodiment, the biofilms growth reducing coating consists of a sol-gel matrix and the composition consists of three partially hydrolyzed and/or condensed silanes. In yet another embodiment, the biofilms growth reducing coating consists of a sol-gel matrix and the composition consists of four partially hydrolyzed and/or condensed silanes.

[0041 ] In an embodiment, the biofilms growth reducing surface coating composition comprises a sol-gel matrix obtained from two, three or four partially hydrolyzed and/or condensed silanes, and the composition is optionally further comprising one or more antifouling compounds additives, preferably incorporated by solubilisation or by suspension in the sol-gel matrix precursors.

[0042 ] In an embodiment, the antifouling compounds are sequestered in the structure of the hydrophobic xerogel surface in order to generate the biofilms growth reducing activity. [0043 ] A sequestered antifouling compound, as used herein, unless otherwise expressly stated, refer to a compound that is presenting a leaching profile of less than 10 μg/cm ² /d in a standard leaching test in water described herein. Preferably, the leaching profile should be less than 1 μg/cm ² /d or even more preferably, less than 0,1 μg/cm ² /d.

[0044 ] In an embodiment, the biofilms growth reducing surface coating composition comprises xerogel film is prepared from a sol-gel matrix obtained from partial hydrolysis of silanes

(e.g., long-chain alkyltrialkoxysilanes , short-chain alkyltrialkoxysilanes , perfluororalkyltrialkoxysilanes , trialkoxysilane-tetraalkylammonium halide) composition.

Antifouling compound additives are optionally incorporated in the sol-gel matrix either by solubilisation or by suspension. The surface coatings are used in a method for reducing biofilms growth on surfaces . The method can reduce biofilms growth by killing (partially or completely) microorganism that come in contact with the surface .

[0045 ] In an embodiment, the biofilms growth reducing surface coating composition comprises a sol-gel matrix obtained from two, three or four partially hydrolyzed and/or condensed silanes, and the composition is further comprising a solvent, preferably an alcohol or a mixture of alcohols and even more preferably methanol, ethanol, isopropanol or octanol or mixtures thereof.

[0046 ] In an embodiment, a first silane is a long-chain alkyltrialkoxysilane or a perfluoalkyltrialkoxysilane . A second silane is a shorter-chain alkyltrialkoxysilane . A third silane is a tetraalkoxysilane .

[0047 ] In an embodiment, the third silane makes up the remainder of the precursor composition.

[0048 ] In the following embodiments, the mole % of the described silanes account for the relative amounts of the silanes. The total mole % of any combination in any given embodiment accounts to 100%.

[0049 ] In an embodiment, the three-component xerogel surface incorporates 0.01 mole % to 5.0 mole % of a quaternary ammonium silanes silane precursor in combination with 20 mole % to 55 mole % of a shorter-chain alkyltrialkoxysilane (such as, but not limited to, methyltrimethoxysilane (CI), n- propyltrimethoxysilane (C3) or n-octyltriethoxysilane (C8)) and a tetraalkoxysilane (such as, but not limited to, tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), or tetraisopropoxysilane (TIPOS).

[0050 ] In an embodiment, the three-component xerogel surface incorporates 0.01 mole % to 5.0 mole % of a long-chain alkyltrialkoxy silane (where long-chain refers to ten (10) or more carbons, such as, but not limited to, n- dodecyltriethoxysilane (C12) or n-octadecyltriethoxysilane

(C18)) in combination with 20 mole % to 55 mole % of a shorter-chain alkyltrialkoxysilane (such as, but not limited to, methyltrimethoxysilane (CI), n-propyltrimethoxysilane (C3) or n-octyltriethoxysilane (C8)) and a tetraalkoxysilane (such as, but not limited to, tetramethoxysilane (TMOS) , tetraethoxysilane (TEOS), or tetraisopropoxysilane (TIPOS) .

[0051] In an embodiment, the four-component xerogel surface incorporates 0.01 mole % to 5.0 mole % of a quaternary ammonium silane precursor and 0.25 mole % to 5.0 mole % of a long-chain alkyltrialkoxy silane (where long-chain refers to ten (10) or more carbons, such as, but not limited to, n- dodecyltriethoxysilane (C12) or n-octadecyltriethoxysilane

(C18)) precursor in combination with 20 mole % to 55 mole % of a shorter-chain alkyltrialkoxysilane (such as, but not limited to, n-propyltrimethoxysilane (C3) or n-octyltriethoxysilane

(C8)) and a tetraalkoxysilane (such as, but not limited to, tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), or tetraisopropoxysilane (TIPOS).

[0052 ] In an embodiment, the four-component xerogel surface incorporates 0.01 mole % to 5.0 mole % of a quaternary ammonium silane precursor, 1 mole % to 45 mole % of a long- chain perfluoroalkyltrialkoxysilane (where long-chain refers to eight (8) or more carbons such as, but not limited to, tridecafluorooctyltriethoxysilane (TDF) or tridecafluorooctyltrimethoxysilane ) in combination with 20 mole % to 55 mole % of a shorter-chain alkyltrialkoxysilane

(such as, but not limited to, n-propyltrimethoxysilane (C3) or n-octyltriethoxysilane (C8)) and a tetraalkoxysilane (such as, but not limited to, tetramethoxysilane (TMOS) , tetraethoxysilane (TEOS), or tetraisopropoxysilane (TIPOS)) are incorporated in the surface. [0053 ] In an embodiment, the three-component xerogel surface incorporates 0.01 mole % to 5.0 mole % of a quaternary ammonium silane precursor in combination with 20 mole % to 55 mole % of a shorter-chain alkyltrialkoxysilane (such as, but not limited to, methyltrimethoxysilane (CI), n- propyltrimethoxysilane (C3) or n-octyltriethoxysilane (C8)) and a tetraalkoxysilane (such as, but not limited to, tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), or tetraisopropoxysilane (TIPOS)) and an antifouling compound from 0.001 mass % to 60 mass %, or preferably of 0.1 % to 30% mass .

[0054 ] In an embodiment, the two-component xerogel surface incorporates 20 mole % to 55 mole of a shorter-chain alkyltrialkoxysilane (such as, but not limited to, methyltrimethoxysilane (CI), n-propyltrimethoxysilane (C3) or n-octyltriethoxysilane (C8)) and 20 mole % to 55 mole % of a tetraalkoxysilane (such as, but not limited to, tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), or tetraisopropoxysilane (TIPOS)) and an antifouling compound from 0.001 mass % to 60 mass %, or preferably of 0.1 % to 50% mass .

[0055 ] In an embodiment, a first silane is a quaternary ammonium silane, a second silane is short-chain alkyltrialkoxysilane, and a third silane is a tetraalkoxysilane. In an embodiment, 1:49:50 mole % of said quaternary ammonium silane, alkyltrialkoxysilane, and said tetraalkoxysilane are present. [0056 ] In an embodiment, a first silane is a quaternary ammonium silane, a second silane is short-chain alkyltrialkoxysilane, and a third silane is a tetraalkoxysilane . In an embodiment, 0.1:49.9:50 mole % of said quaternary ammonium silane, alkyltrialkoxysilane, and said tetraalkoxysilane are present. In an embodiment an antifouling compound is added, preferably 0.001 mass % to 60 mass %, to the sol-gel matrix. Preferably, the antifouling compound is a metal-based compound (such as copper (I) oxide

(CU ₂ O) or zinc oxide (ZnO)) and is in an amount of 0.1 % to 30% mass.

[0057 ] In an embodiment, a first silane is a long-chain alkyltrialkoxysilane, a second silane is short-chain alkyltrialkoxysilane, and a third silane is a tetraalkoxysilane. In an embodiment, 1:49:50 mole % of said long-chain alkyltrialkoxysilane, short-chain alkyltrialkoxysilane, and said tetraalkoxysilane are present. In an embodiment an antifouling compound is added, preferably 0.001 mass % to 60 mass % of, to the sol-gel matrix. Preferably, the antifouling compound is a metal-based compound (such as copper(I) oxide (Cu ₂ 0) or zinc oxide (ZnO)) and is in an amount of 0.1 % to 50% mass.

[0058 ] In an embodiment, a first silane is a short-chain alkyltrialkoxysilane, and a second silane is a tetraalkoxysilane. In an embodiment, 50:50 mole % of said short-chain alkyltrialkoxysilane, and said tetraalkoxysilane are present. In an embodiment an antifouling compound is added, preferably 0.001 mass % to 60 mass % of, to the sol-gel matrix. Preferably, the antifouling compound is a metal-based compound (such as copper(I) oxide (Cu ₂ 0) or zinc oxide (ZnO) ) and is in an amount of 0.1 % to 50% mass.

[0059 ] In an embodiment, a first silane is a short-chain alkyltrialkoxysilane, and a second silane is a tetraalkoxysilane . In an embodiment, 50:50 mole % of said short-chain alkyltrialkoxysilane, and said tetraalkoxysilane are present. In an embodiment a combination of antifouling compounds are added, preferably 0.001 mass % to 60 mass % of, to the sol-gel matrix. Preferably, the antifouling compound is a metal-based compound (such as copper (I) oxide (Cu ₂ 0) or zinc oxide (ZnO) ) and is in an amount of 0.1 % to 50% mass.

[0060 ] The sol-gel precursors are long-chain alkyltrialkoxysilanes , short-chain alkyltrialkoxysilanes , perfluororalkyltrialkoxysilanes and quaternary ammonium silane. The sol-gel precursors can be obtained from commercial sources or synthesized by known methods.

[0061 ] The long-chain alkyltrialkoxysilane has a long-chain alkyl group and three alkoxy groups. In one embodiment, the long-chain alkyltrialkoxysilane has the following structure: where, in this structure, R' is a long-chain alkyl group and R is an alkyl group of an alkoxy group. The long chain alkyl group is a Cio to C30, including all integer numbers of carbons and ranges there between, alkyl group. The alkoxy groups are, independently, Ci, C ₂ , or C ₃ alkoxy groups. The alkoxy groups can have the same number of carbons . The long-chain alkyltrialkoxysilane is present as a first component at from 0.25 mole % to 5.0 mole %, including all values to the 0.1 mole % and ranges there between, or as a second component at 1 mole % to 45 mole %, including all integer mole % values and ranges there between. Examples of suitable long-chain alkyltrialkoxysilanes include n-dodecyltriethoxysilane, n- octadecyltriethoxysilane, and n-decyltriethoxysilane .

[0062 ] An alkane functionality can be incorporated within the xerogel coatings using the sol-gel process . Mixed alkane and perfluoroalkane modifications can be incorporated from appropriate perfluoroalkyl- and alkyltrialkoxysilanes precursors .

[0063 ] In one embodiment, the short-chain alkyltrialkoxysilane has the following structure:

(RO) ₃ -Si-R'

where, in this structure, R' is a short-chain alkyl group and R is an alkyl group of an alkoxy group. The short-chain alkyltrialkoxysilane has a short-chain alkyl group and three alkoxy groups. The short-chain alkyl group is a C3 to Ce, including all integer numbers of carbons and ranges there between, alkyl group The alkoxy groups are, independently, Ci, C ₂ , or C ₃ alkoxy groups. The alkoxy groups can have the same number of carbons. The short-chain alkyltrialkoxysilane is present at 20 mole % to 55 mole %, including all integer mole % values and ranges there between. Examples of suitable short- chain alkyltrialkoxysilanes include n-propyltrimethoxy silane, n-butyltriethoxysilane , n-pentyltriethoxysilane, n- hexyltriethoxysilane, n-heptyltriethoxysilane, n- octyltriethoxysilane, and branched analogues thereof. [0064 ] In one embodiment, the silane is a short-chain amino- alkyltrialkoxysilane has the following structure:

where, in this structure, R' is a short-chain alkyl group and R is an alkyl group of an alkoxy group. The short-chain alkyltrialkoxysilane has a short-chain alkyl group and three alkoxy groups. The short-chain alkyl group is a C ₃ to C ₈ , including all integer numbers of carbons and ranges there between, alkyl group The alkoxy groups are, independently, Ci, C2, or C3 alkoxy groups. The alkoxy groups can have the same number of carbons. The short-chain alkyltrialkoxysilane is present at 20 mole % to 55 mole %, including all integer mole % values and ranges there between. Examples of suitable short- chain alkyltrialkoxysilanes include 3- Aminopropyltrimethoxysilane (SiNH ₂ ).

[0065 ] A fluoroalkane functionality can be incorporated within the xerogel coatings using the sol-gel process . Mixed alkane and perfluoroalkane modifications can be incorporated from appropriate perfluoroalkyl- and alkyltrialkoxysilanes precursors .

[0066 ] In one embodiment, the perfluoroalkyltrialkoxysilane has the following structure:

(RO) ₃ -Si-R'

where, in this structure, R' is a perfluoroalkyl group and R is an alkyl group of an alkoxy group. The perfluoroalkyltrialkoxysilane has a perfluoroalkyl group and three alkoxy groups. The pefluoroalkyl group is a C ₈ to C ₃₀ , including all integer numbers of carbons and ranges there between, alkyl group. The alkoxy groups are, independently, Ci , C ₂ , or C ₃ alkoxy groups. The alkoxy groups can have the same number of carbons. The perfluoroalkyltrialkoxysilane is present at 1 mole % to 45 mole %, including all integer mole values and ranges therebetween. Examples of suitable perfluoroalkyltrialkoxysilanes include tridecafluorooctadecyltriethoxysilane and tridecafluorooctyltrimethoxysilane .

[0067 ] Quaternary ammonium salts functionality can also be incorporated within the xerogel coatings using the sol-gel process . Mixed quaternary ammonium salts modifications can be incorporate from appropriate quaternary ammonium silanes .

[0068 ] The quaternary ammonium silanes have one, two or three quaternary ammonium group and one, two or three alkoxy groups. In one embodiment, the quaternary ammonium silanes has the following structure:

(RO) ₃ Si-Z-N ⁺ R ² R ³ R ⁴ X ^"

where, in this structure, each R independently represents an alkyl group having 1 to 4 carbon atoms; Z represents an alkylene group having 1 to 30 carbon atoms; each of the groups R ² R ³ and R ⁴ independently represents an alkyl or hydroxyalkyl group having 1 to 30 carbon atoms or an aralkyl radical having 7 to 10 carbon atoms; and X represents an anion. Two of the groups R ² R ³ and R ⁴ may be joined to form a heterocyclic ring, or the N+R ² R ³ R ⁴ moiety can be a pyridinium group.

[0069 ] In one embodiment, in the quaternary ammonium silanes each R independently represents an alkyl group having 1 to 3 carbon atoms; Z represents an alkylene group having 1 to 5 carbon atoms; each of the groups R ² R ³ and R ⁴ independently represents an alkyl or hydroxyalkyl group having 1 to 20 carbon atoms or an aralkyl- radical comprising 1-3 alkyl carbon atoms and 6 aryl carbon atoms; or N ⁺ R ² R ³ R ⁴ can be a pyridinium group and X represents an anion selected from chloride, bromide, fluoride, iodide, sulphonate group, or acetate .

[0070] In one embodiment, in the quaternary ammonium silanes each R independently represents CH3- or CH3CH2-; Z represents a propylene; each of the groups R ² R ³ and R ⁴ independently represents CH ₃ , CH ₃ CH ₂ , Ci ₀ H ₂ i, Ci ₈ H ₃ 7 or CH ₂ C ₆ H ₅ ; and X represents a chloride or bromide .

[0071] The quaternary ammonium silanes is present as a first component at from 0.001 mole % to 10.0 mole %, including all values to the 0.001 mole % and ranges there between, or as a second component at 1 mole % to 45 mole %, including all integer mole % values and ranges there between.

[0072] Examples of suitable quaternary ammonium silanes include (CH ₃ 0) 3Si (CH2)3 ⁺ (CH ₃ ) 2 C18H37 CI,

(CH3O) ₃ Si (CH ₂ ) ₃ N ⁺ CH ₃ (C10H21) 2 CI, (CH ₃ 0) 3Si (CH2)3 ⁺ (CH ₃ ) 2 C18H37 Br, (CH3O) ₃ Si (CH ₂ ) ₃ N ⁺ CH ₃ (C10H21) 2 Br, (C2H5O) ₃ Si (CH ₂ ) ₃ N ⁺ (CH ₃ ) 2C18H37 CI, (CH3O) ₃ Si (CH ₂ ) ₃ N ⁺ (CH ₃ ) 2CH ₂ C ₆ H ₅ CI, (CH ₃ 0) 3Si (CH2)3 ⁺ (CH ₃ ) 3 CI, (CH ₃ 0) 3Si (CH2)3 ⁺ (CH3) ₂ C ₄ H ₉ CI, CH ₃ 0) 3Si (CH2)3 ⁺ (C2H ₅ ) 3 CI and pyridiniumpropyltrimethoxysilane chloride .

[0073] The quaternary ammonium silanes can be partially hydrolysed, that is some of the groups RO- can be HO- groups . The quaternary ammonium organosilane can be in pure monomeric form or can be partially condensed. The quaternary ammonium organosilane preferably retains an average of at least one silicon-bonded alkoxy group per silicon atom.

[0074 ] Short-chain amino-alkyltrialkoxysilanes and quaternary ammonium silanes as defined herein are not mixed together to form a combination of silanes as part of this disclosure.

[0075 ] In one embodiment, the tetraalkoxysilane has the following structure:

where, in this structure, R is an alkyl group of an alkoxy group. The alkoxy groups are, independently, Ci, C ₂ , or C ₃ alkoxy groups. The alkoxy groups can have the same number of carbons .

[0076 ] In one embodiment, the antifouling compound is any agent that kill biofouling organisms or stop their growth. The antifouling compound is present in solution or as disperse solid particles at from 0.001 mass % to 60.0 mass %, including all values to the 0.001 mole % and ranges there between.

[0077 ] The sol-gel matrix or coating compositions comprise functional groups derived from the precursor silanes . For example, coatings formed using perfluoroalkyltrialkoxysilanes have perfluoroalkyl groups. The surface coatings also have residual silanol functional groups. The groups can be on the surface of the film or in the bulk matrix of the film.

[0078 ] The thickness of the xerogel can be varied based on the deposition method and/or parameters of the deposition process (e.g., concentrations of the precursor components) . For example, the film can have a thickness of 1 micron to 150 microns, including all integer thickness values and ranges there between.

[0079 ] The sol-gel matrix surface coatings have desirable properties. For example, the coatings have desirable wetting properties (which can be measured by, for example, contact angle) and fouling release properties.

[0080 ] In an embodiment, the biofilms growth reducing surface coating composition comprises a sol-gel matrix made by a method comprising the following steps: forming a precursor composition comprising two, three or more sol-gel precursor components, coating the precursor composition on a surface such that a sol-gel matrix film is formed on the surface.

[0081 ] In an embodiment, the biofilms growth reducing surface coating composition comprises a sol-gel matrix made by a method comprising the following steps: forming a precursor composition comprising two, three or more sol-gel precursor components, adding one or more antifouling compounds, coating the precursor composition on a surface such that a sol-gel matrix film is formed on the surface.

[0082 ] Generally, the precursor composition (referred to herein as a sol or sol-gel) is formed by combining two, three or more sol-gel precursor components and allowing the components to stand for a period of time such that a desired amount of hydrolysis and polymerization of the precursors occurs . This precursor composition is coated on a surface and allowed to stand for a period of time such that a xerogel film is formed. The determination of specific reaction conditions (e.g., mixing times, standing times, acid/base concentration, solvent (s)) for forming the xerogel film is within the purview of one having skill in the art.

[0083 ] In another aspect, the present disclosure provides methods for reducing biofilms growth by killing (partially or completely) marine microorganism that come in contact with a surface comprising applying to the surface, prior to biofilms formation, the combination of silanes, the sol-gel matrix, and optionally antifouling compound, composition or coating described herein.

[0084 ] In another aspect, the present invention provides methods for preventing biofilm growth on surfaces subjected to an aqueous environment comprising applying, prior to exposing said surface to said aqueous environment, the combination of silanes, the sol-gel matrix, and optionally antifouling compound, composition or coating described herein. The methods can prevent biofilm growth by lowering (partially or completely) the biofilm thickness.

[0085 ] In another aspect, the present invention provides methods for preventing biofilm growth on surfaces subjected to an aqueous environment comprising applying to the surface, prior to exposing said surface to said aqueous environment, the combination of silanes, the sol-gel matrix, and optionally antifouling compound, composition or coating described herein. The methods can prevent biofilm growth by lowering (partially or completely) the biofilm coverage area. [0086 ] In another aspect, the present invention provides methods for preventing biofilm growth on surfaces subjected to an aqueous environment comprising applying to the surface, prior to exposing said surface to said aqueous environment, the combination of silanes, the sol-gel matrix, and optionally antifouling compound, composition or coating described herein. The methods can prevent biofilm growth by lowering (partially or completely) the cellular viability in the biofilm.

[0087 ] Aqueous environments are any aqueous media in which biofilms can form. Examples of such aqueous environments include freshwater and saltwater environments. The aqueous environments can be naturally occurring or man-made. Examples of aqueous environments include tanks of freshwater or saltwater, rivers, lakes and oceans. The aqueous environments can also occur following the condensation of vapor on a cold surface .

[0088 ] In another aspect, the present invention provides methods for preventing natural biofilm growth on surfaces subjected to sea water from the gulf of the Saint Lawrence River comprising applying to the surface, prior to exposing said surface to said water, the combination of silanes, the sol-gel matrix, and optionally antifouling compound, composition or coating described herein. The methods can prevent biofilm growth by lowering (partially or completely) the biofilm coverage area and by lowering (partially or completely) the cellular viability in the biofilm when compared to an unprotected surface. [0089 ] In another aspect, the present invention provides methods for preventing natural biofilm growth on surfaces subjected to marine bacterial strains like Vibrio splendidus , Pseudoaltermonas haloplanktis , Shewanella colwelliana , Planococcus kocurii and Roseobacter denitrificans comprising applying to the surface, prior to exposing said surface to said marine bacterial strains, the combination of silanes, the sol-gel matrix, and optionally antifouling compound, composition or coating described herein. The methods can prevent biofilm growth by lowering (partially or completely) the biofilm coverage area.

[0090 ] The surface is any surface that can be colonised by biofilms . The surfaces can be materials such as metals (such as marine grade aluminum), plastics, composites (such as fiberglass), glass, wood, or other natural fibers. Examples of suitable surfaces include surfaces of a water-borne vessel such as a boat, ship and personal watercraft . Others examples of suitable surfaces includes concreate, sandwich walls and stainless steel.

[0091 ] In an embodiment, the method comprises the step of applying the combination of silanes, the sol-gel matrix, and optionally antifouling compound, composition or coating described herein as described herein to at least a portion of a surface to form an ORMOSIL xerogel film prior to biofilm colonisation on the surface.

[0092 ] The coating of biofilms growth reduction coating composition can be applied by a variety of coating methods . Examples of suitable coating methods including spray coating, dip coating, brush coating, or spread coating.

[0093 ] The sol-gel matrix coating can be formed by acid- catalyzed hydrolysis and polymerization of the precursor components. In an embodiment, the biofilms growth reduction precursor composition further comprises an acidic component that makes the pH of the composition sufficiently acidic so that the components undergo acid-catalyzed hydrolysis to form the sol-gel matrix. Examples of suitable acidic components include aqueous acids such as hydrochloric acid, hydrobromic acid and trifluoroacetic acid. Examples of suitable acidic components include organic acids such as acetic acid, cinnamic acid and salicylic acid. Conditions and components required for acid-based hydrolysis of sol-gel components are known in the art .

[0094 ] After applying the coating of the biofilms growth reduction coating composition, the coating is allowed to stand for a time sufficient to form the xerogel . Depending on the thickness of the coating, the standing time is, for example, from 1 hour to 72 hours including all integer numbers of hours and ranges there between and up to 1 or more days .

[0095 ] The steps of the methods described in the various embodiments and examples disclosed herein are sufficient to practice the methods of the present disclosure. Thus, in an embodiment, the method consists essentially of a combination of the steps of a method disclosed herein. In another embodiment, the method consists of such steps. [0096] The following examples are presented to illustrate the present disclosure. They are not intended to be limiting in any manner.

Materials and Methods .

[0097] Chemical Reagents. Deionized water was prepared to a specific resistivity of at least 18 ΜΩ using a Barnstead NANOpure Diamond UV ultrapure water system. Tetraethoxysilane or tetraethyl orthosilicate (TEOS) , n- octadecyltrimethoxysilane (C18), n-octyltriethoxy-silane (C8), n-propyltriethoxy-silane (C3), octadecyldimethyl ( 3- trimethoxysilylpropyl ) -ammonium chloride (72% in methanol) (SiQAC) , Tridecafluoro-1 , 1,2, 2-tetrahydrooctyl-triethoxysilane (SiTDF) and 3-Aminopropyltrimethoxysilane (SiNH2)were

purchased from Gelest Inc. and were used as received. Copper oxide (I), fumed silica, cinnamic acid, salicylic acid and zinc oxide were purchased from Aldrich and used as received.

Isopropanol was purchased from Quantum Chemical Corp.

Hydrochloric acid was obtained from Fisher Scientific Co.

Copper thiocyanate and titanium dioxide were purchased from Alfa Aesar and used as received. Zinc pyrithione and Irganol™ were purchased from CombiBlock and used as received. Zineb and Econea were purchased from BOC Science and used as received. Borosilicate glass microscope slides were obtained from Fisher Scientific, Inc.

[0098] Sol Preparation, The sol/xerogel composition is designated in terms of the molar ratio of Si-containing precursors. Thus, a 50:50 C8/TEOS composition contains 50 mole % C8 and 50 mole % TEOS. General procedure. Unless noted, all sol are prepared in isopropanol using aqueous HC1 as the catalyst. Alkyl silanes are placed in a round bottomed flask equipped with mechanical stirrer along with the alcohol and the TEOS . This mixture is stirred for 5 minutes and a 0.1 N solution of the acid in water is slowly added. The reaction mixture is then capped and stirred at ambient temperature for 24 hours.

[0099] Sol TEOS. TEOS (3.96 g, 17.1 mmol, 3.35 mL), water (0.54 mL) , isopropanol (3.40 mL) , and HCL (0.1 M, 15 μL) were stoppered in a glass vial and stirred at ambient temperature for 6 hours .

[0100 ] 50:50 C8/TEOS. A mixture of TEOS (2.70 g, 13 mmol), C8 (3.59 g, 13 mmol), isopropanol (5.0 mL) and 0.1 N HC1 (1.6 mL,

0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0101] 50:50 C8/TEOS (ethanol) . A mixture of TEOS (2.70 g, 13 mmol), C8 (3.59 g, 13 mmol), ethanol (5.0 mL) and 0.1 N HC1 (1.6 mL, 0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0102 ] 50:50 C8/TEOS (octanol) . A mixture of TEOS (2.70 g, 13 mmol), C8 (3.59 g, 13 mmol), octanol (5.0 mL) and 0.1 N HC1 (1.6 mL, 0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0103] 50:50 C8/TEOS (no solvent). A mixture of TEOS (2.70 g, 13 mmol), C8 (3.59 g, 13 mmol), and 0.1 N HC1 (1.6 mL, 0.16 mmol) was capped and stirred at ambient temperature for 24 hours .

[0104] 50:50 C8/TEOS (acetic acid). A mixture of TEOS (2.70 g, 13 mmol), C8 (3.59 g, 13 mmol), isopropanol (5.0 mL) and 0.1 N acetic acid (1.6 mL) was capped and stirred at ambient temperature for 24 hours.

[0105] 50:50 C8/TEOS (cinnamic acid). A mixture of TEOS (2.70 g, 13 mmol), C8 (3.59 g, 13 mmol), isopropanol (5.0 mL) , water (1.6 mL) and cinnamic acid (0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0106] 50:50 C8/TEOS (salicylic acid). A mixture of TEOS (2.70 g, 13 mmol), C8 (3.59 g, 13 mmol), isopropanol (5.0 mL) , water (1.6 mL) and salicylic acid (0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0107 ] 25:75 C8/TEOS. A mixture of TEOS (4.05 g, 19.5 mmol), C8 (1.795 g, 6.5 mmol), isopropanol (5.0 mL, 87 mmol) and 0.1 N HC1 (1.6 mL, 0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0108 ] 10:90 C8/TEOS. A mixture of TEOS (4.86 g, 23.4 mmol), C8 (0.718 g, 2.6 mmol), isopropanol (5.0 mL, 87 mmol) and 0.1 N HC1 (1.6 mL, 0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0109] 50:50 C3/TEOS. A mixture of TEOS (2.70 g, 13 mmol), C3 (2.68 g, 13 mmol), isopropanol (5.0 mL, 87 mmol) and 0.1 N HC1 (1.6 mL, 0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0110 ] 25:75 C3/TEOS. A mixture of TEOS (4.05 g, 19.5 mmol), C3 (1.34 g, 6.5 mmol), isopropanol (5.0 mL, 87 mmol) and 0.1 N HC1 (1.6 mL, 0.16 mmol) was capped and stirred at ambient temperature for 24 hours.

[0111] 1:49:50 C18/C8/TEOS. A mixture of C18 (0.054 g, 0.14 mmol, 0.061 mL) , C8 (1.95 g, 7.06 mmol, 2.21 mL) , TEOS (1.50 g, 7.20 mmol, 1.61 mL) , 0.1 N HC1 (0.91 mL, 0.09 mmol), and isopropanol (4.62 mL) , was stirred at ambient temperature for 24 hours. [0112 ] 10:40:50 SiTDF/C8 /TEOS . A mixture of SiTDF (0.715 g, 1.4 mmol, 0.061 mL) , C8 (1.59 g, 5.76 mmol), TEOS (1.50 g, 7.20 mmol, 1.61 mL) , 0.1 N HC1 (0.91 mL, 0.09 mmol), and isopropanol (4.62 mL) , was stirred at ambient temperature for 24 hours.

[0113] 1:49:50 QAC/C8 /TEOS . A mixture of QAC (0.069 g, 0.14 mmol, 0.061 mL) , C8 (1.95 g, 7.06 mmol, 2.21 mL) , TEOS (1.50 g, 7.20 mmol, 1.61 mL) , 0.1 N HC1 (0.91 mL, 0.09 mmol), and isopropanol (4.62 mL) , was stirred at ambient temperature for 24 hours.

[0114] 1:49:50 QAC/C3/TEOS . A mixture of QAC (0.069 g, 0.14 mmol, 0.061 mL) , C3 (1.46 g, 7.06 mmol), TEOS (1.50 g, 7.20 mmol, 1.61 mL) , 0.1 N HC1 (0.91 mL, 0.09 mmol), and isopropanol (4.62 mL) , was stirred at ambient temperature for 24 hours. [0115] 0.1:49.9:50 QAC/C8/TEOS. A mixture of QAC (0.0069 g, 0.014 mmol, 0.061 mL) , C8 (1.95 g, 7.06 mmol, 2.21 mL), TEOS (1.50 g, 7.20 mmol, 1.61 mL) , 0.1 N HC1 (0.91 mL, 0.09 mmol), and isopropanol (4.62 mL) , was stirred at ambient temperature for 24 hours.

[0116] 0.1:49.9:50 SiNH2 /C8 /TEOS . A mixture of SiNH2 (0.00251 g, 0.014 mmol), C8 (1.95 g, 7.06 mmol, 2.21 mL) , TEOS (1.50 g, 7.20 mmol, 1.61 mL) , 0.1 N HC1 (0.91 mL, 0.09 mmol), and isopropanol (4.62 mL) , was stirred at ambient temperature for 24 hours.

[0117 ] Anti-biofilm compounds and pigments addition. The anti-biofilm / sol-gel composition is designated as mass ratio. Thus, a 1% Cu ₂ O-50:50 C8/TEOS contain 0.1 g of Cu ₂ 0 in 10 g of the 50:50 C8/TEOS sol.

[0118 ] 0.1% Cu ₂ O-50:50 C8/TEOS. 0.01 g of Cu ₂ 0 was placed in 10 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0119] 1% Cu ₂ O-50:50 C8/TEOS. 0.1 g of Cu ₂ 0 was placed in 10 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0120 ] 5% Cu ₂ O-50:50 C8/TEOS. 0.5 g of Cu ₂ 0 was placed in 10 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h. [0121] 10% Cu ₂ O-50:50 C8/TEOS. 1 g of Cu ₂ 0 was placed in 10 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h. [0122 ] 20% Cu ₂ O-50:50 C8/TEOS. 2 g of Cu ₂ 0 was placed in 10 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0123] 30% Cu ₂ O-50:50 C8/TEOS. 3 g of Cu ₂ 0 was placed in 10 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0124] 30% Cu ₂ O-20% ZnO-50:50 C8/TEOS. 3 g of Cu ₂ 0 and 2g of ZnO were placed in 10 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0125] 0.1% Cu ₂ O-0.1 : 49.9 : 50 QAC/C8/TEOS. 0.01 g of Cu ₂ 0 was placed in 10 g of the 0.1:49.9:50 QAC/C8/TEOS and the mixture was shaken at room temperature for 4h.

[0126] 10% Cu ₂ O-l:49:50 QAC/C8/TEOS. 10 g of Cu ₂ 0 was placed in 100 g of the 1:49:50 QAC/C8/TEOS and the mixture was shaken at room temperature for 4h. [0127 ] 5% Cu ₂ O-0.1 : 49.9 : 50 QAC/C8/TEOS. 5 g of Cu ₂ 0 was placed in 100 g of the 0.1:49.9:50 QAC/C8/TEOS and the mixture was shaken at room temperature for 4h.

[0128 ] 1% Copper thiocyanate-50 : 50 C8/TEOS. 1 g of copper thiocyanate was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h. [0129] 5% Copper thiocyanate-50 : 50 C8/TEOS. 5 g of copper thiocyanate was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0130 ] 1% Zinc pyrithione-50 : 50 C8/TEOS. 1 g of zinc pyrithione was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h. [0131] 5% Zinc pyrithione-50 : 50 C8/TEOS. 5 g of zinc pyrithione was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0132 ] 10% TiO ₂ -50:50 C8/TEOS. 10 g of Ti0 ₂ was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0133] 20% TiO ₂ -50:50 C8/TEOS. 20 g of Ti0 ₂ was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0134] 1% Zineb-50:50 C8/TEOS. 1 g of zineb was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0135] 10% Cu ₂ 0, 0,1% zineb-50:50 C8/TEOS. 10 g of Cu ₂ 0 and 0,lg of zineb were placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h. [0136] 10% Ti0 ₂ , 0,1% zineb-50:50 C8/TEOS. 10 g of Ti0 ₂ and 0,lg of zineb were placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h. [0137 ] 1% Econea-50:50 C8/TEOS. 1 g of econea was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0138 ] 10% Cu ₂ 0, 0,1% econea-50:50 C8/TEOS. 10 g of Cu ₂ 0 and 0,lg of econea were placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0139] 10% Ti0 ₂ , 0,1% econea-50:50 C8/TEOS. 10 g of Ti0 ₂ and 0,lg of econea were placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0140 ] 10% Cu ₂ O-50:50 C3/TEOS. 10 g of Cu ₂ 0 was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0141] 20% Cu ₂ O-50:50 C3/TEOS. 20 g of Cu ₂ 0 was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h. [0142 ] 1% Copper thiocyanate-50 : 50 C3/TEOS. 1 g of copper thiocyanate was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0143] 5% Copper thiocyanate-50 : 50 C3/TEOS. 5 g of copper thiocyanate was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h. [0144] 1% Zinc pyrithione-50 : 50 C3/TEOS. 1 g of zinc pyrithione was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0145] 5% Zinc pyrithione-50 : 50 C3/TEOS. 5 g of zinc pyrithione was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h. [0146] 1% Irgarol-50 : 50 C8/TEOS. 1 g of irgarol was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0147 ] 10% Cu ₂ 0, 0,1% irgarol-50 : 50 C8/TEOS. 10 g of Cu ₂ 0 and 0,lg of irgarol were placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0148 ] 10% Ti0 ₂ , 0,1% irgarol-50 : 50 C8/TEOS. 10 g of Ti0 ₂ and 0,lg of irgarol were placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0149] 10% TiO ₂ -50:50 C3/TEOS. 10 g of Ti0 ₂ was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0150 ] 20% TiO ₂ -50:50 C3/TEOS. 20 g of Ti0 ₂ was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h. [0151] 1% Zineb-50:50 C3/TEOS. 1 g of zineb was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h. [0152 ] 10% Cu ₂ 0, 0,1% zineb-50:50 C3/TEOS. 10 g of Cu ₂ 0 and 0,lg of zineb were placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0153] 10% Ti0 ₂ , 0,1% zineb-50:50 C3/TEOS. 10 g of Ti0 ₂ and 0,lg of zineb were placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0154] 1% Irgarol-50 : 50 C3/TEOS. 1 g of irgarol was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0155] 10% Cu ₂ 0, 0,1% irgarol-50 : 50 C3/TEOS. 10 g of Cu ₂ 0 and

0,lg of irgarol were placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0156] 10% Ti0 ₂ , 0,1% irgarol-50 : 50 C3/TEOS. 10 g of Ti0 ₂ and

0,lg of irgarol were placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h. [0157 ] 1% Econea-50:50 C3/TEOS. 1 g of econea was placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0158 ] 10% Cu ₂ 0, 0,1% econea-50:50 C3/TEOS. 10 g of Cu ₂ 0 and 0,lg of econea were placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h. [0159] 10% Ti0 ₂ , 0,1% econea-50:50 C3/TEOS. 10 g of Ti0 ₂ and

0,lg of econea were placed in 100 g of the 50:50 C3/TEOS and the mixture was shaken at room temperature for 4h.

[0160 ] 0.1% Cu ₂ O-0.1:49.9:50 SiNH2 /C8 /TEOS . 0.1 g of Cu ₂ 0 was placed in 100 g of the 0.1:49.9:50 SiNH2/C8/TEOS and the mixture was shaken at room temperature for 4h. [0161] 1% Fumed silica-50:50 C8/TEOS. 1 g of fumed silica was placed in 100 g of the 50:50 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0162 ] 5% Cu ₂ O-0.1 : 49.9 : 50 QAC/C3/TEOS. 5 g of Cu ₂ 0 was placed in 100 g of the 0.1:49.9:50 QAC/C3/TEOS and the mixture was shaken at room temperature for 4h.

[0163] 30% Cu ₂ 0-25:75 C8/TEOS. 30 g of Cu ₂ 0 was placed in 100 g of the 25:75 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0164] 30% Cu ₂ O-10:90 C8/TEOS. 30 g of Cu ₂ 0 was placed in 100 g of the 10:90 C8/TEOS and the mixture was shaken at room temperature for 4h.

[0165] 30% Cu ₂ 0-25:75 C3/TEOS. 30 g of Cu ₂ 0 was placed in 100 g of the 25:75 C3/TEOS and the mixture was shaken at room temperature for 4h. [0166] Xerogel Film Formation. Xerogel films were formed by foam brush coating of the sol precursor onto 25-mm x 75-mm glass microscope slides. The slides were soaked in piranha solution for 24 hours, rinsed with copious quantities of deionized water then soaked in isopropanol for 10 minutes, were air dried and stored at ambient temperature. All coated surfaces were dried at ambient temperature for at least 1 days prior to analysis.

[0167] Metal leaching analysis. The coated glass slides coated as described above were placed in 100 mL of deionized water at room temperature for 15 days. After this time, copper concentration in water was analysed by ICP. Results are calculate as the amount of metal leached from 1 cm ² of surface in 1 day (g/cm ² /d) .

[0168] Marine biofilm growth test. Three marine biofilm growth experiments were needed to test seven coatings . In these experiments, the reaction medium is composed of the natural winter diversity of the usual marine microbial organisms in the St. Lawrence Estuary (Rimouski) . For biofilm, it is microbiofouling composed of multispecies bacteria in natural growth condition. 50:50 C8/TEOS and 1:49:50 QAC/C8/TEOS were tested from March 1 to March 22 2017 in 1 aquarium. 0.1% Cu ₂ O-50:50 C8/TEOS, 0.1% Cu ₂ O-0.1 : 49.9 : 50 QAC/C8/TEOS and 30% Cu ₂ O-20% ZnO-50:50 C8/TEOS were tested from March31 to April 21 2017 in 3 different aquariums. 0.1:49.9:50 QAC/C8/TEOS and 1:49:50 C18/C8/TEOS were tested from April 5 to April 26 2017 in 1 aquarium. All analysis were realised on 5 replicates of every coatings and negative controls were run during each experiments . For each experiment, coated glass slides were left at the bottom of the aquarium for 3 weeks in natural sea water from the gulf of the Saint Lawrence River (Rimouski) . Water was kept at 22 °C. Oxygen was added by a bubbling mechanism and water level was kept constant by recirculation. Nutriments were added at the start of the experiments (TO) to insure a good bacterial growth in the aquariums . Bacterial abundance was measured in each aquariums water at TO and T21 using the flux cytometry methodology. Biofilms were analysed by confocal laser scanning microscopy (CLSM) with a LSM700 (Carl Zeiss, Germany) using a 40X magnification. Biofilms were directly stained with LIVE/DEAD® Bac Light™ Bacterial Viability Kit. The CLSM was used to measured 4 parameters; biofilm thickness, cellular disposition in the biofilm, amount of surface cover by the biofilm, amount of biofilm removed with a water jet (from a cleaning flask) . Statistical analysis of the result was performed using an ANOVA factor with SYSTAT 12.0 (Systat Software Inc., Chicago, USA) with a probability of 0.05. Normality of data was tested using the Kolmogorov-Smirnov methodology .

[0169] Bacterial biofilm culture growth tests. Five marine bacterial strains {Vibrio splendidus 7SHRW (Mateo et al . 2009, Journal of Invertebrate Pathology, 102:50-56.);

Pseudoaltermonas haloplanktis (ATCC ^® 14393™) ; Shewanella colwelliana (ATCC ^® 39565™); Planococcus kocurii (ATCC ^® 43650™) and Roseobacter denitrificans (ATCC ^® 33942™) ) were chosen to studies the bacterial adhesion in presence of the antifouling paint. Each marine bacterial strain was grown overnight in Marine Broth medium (Difco 2216) at room temperature. Cultures were centrifuged at 5 000 rpm for 5 min. Bacterial cell pellets were washed thrice in physiological water ( 9∞ of NaCl, pH 7.2, 0.2 \im filtered and autoclaved) to remove any residual growth medium. Then, bacterial cell suspensions were diluted in sterile physiological water to obtain working bacterial suspensions containing 10 ⁸ cell.mL ^-1 . Preparation of adhesion surfaces and formation of marine biofilm. Coatings were applied to wells of a 96-well microplate using a foam brush. Two coats of paint were applied in the wells at one-hour intervals. All biofilms were formed in 96-well microplates for 48 hours at room temperature without agitation in 8 replicates. The biofilms were composed of one strain, two, three, four or five bacterial strains in the presence of all antifouling paints. All biofilms were formed with 10 ⁷ cell.mL- ¹ . After 48 hours, the biofilms formed were analyzed by spectrometry according to modify protocol of Jackson et al . (2002, Journal of Bacteriology 184:290-301) . Briefly, the microplates were inverted to remove the supernatant and all wells were cleaned with phosphate buffer water (pH 7.2, 0.2 \im filtered and autoclaved) three times to remove any unadhered bacterial cells. Subsequently, 0.1% crystal violet was added to each of the wells to mark the adhered cells for 15 minutes. The crystal violet was then removed and the wells were cleaned three times with phosphate buffer to remove excess colouration. Finally, 70% ethanol was added to each of the wells and the microplates were analyzed by spectrometry at a wavelength of 630 nm (Multiskan Ascent, Thermo Fisher, USA) . For each experiment, background staining was corrected by subtracting the crystal violet bound to uninoculated controls. Treatment of results . All biofilms were treated as percent adhesion according to the following equation: (DO ₆ 30nm biofilm treated / DO630nm biofilm control) *100. Results .

[0170] Preparation of samples. Sol-gel formation as describe herein generates colorless liquids in which anti-fouling compounds, pigments and thickeners can easily be incorporated, by solubilisation or simply by suspension. During the xerogel film formation, any antifouling compound gets sequestered in the film. For instance, suspensions of copper (I) oxide were prepared (0.1%, 1%, 5%, 10%, 20% and 30%) and these mixture were coated by foam brush on glass slides to generate hydrophobic coatings.

[0171] The incorporation of alkyl silanes in the sol-gel composition is essential to generates crackles and smooth ORMOSIL xerogel surfaces with a good adherence to most substrates. Also, the presence of the alkyl group in the xerogel will generate hydrophobic surfaces that have fouling release proprieties. [0172] Copper leaching. Static copper leaching analysis of these xerogel films demonstrated that less than 5.7*10 ^~8 g of Cu/cm ² /d was leached in deionised water for every coating tested. This low amount of copper leaching indicate that the Cu is firmly sequestered in the solid structure of the xerogel.

[0173] Toxicity of xerogel film. Figure 1 shows the bacterial evolution in each aquarium water using the flux cytometry methodology. After 3 weeks of immersion for the 50:50 C8/TEOS, the 1:49:50 C18/C8/TEOS, the 1:49:50 QAC/C8/TEOS, the 0.1:49.9:50 QAC/C8/TEOS, the 0.1% Cu ₂ O-50:50 C8/TEOS and the 0.1% Cu ₂ O-0.1 : 49.9: 50 QAC/C8/TEOS, bacterial evolution was showed to be normal. Only the presence of the 30% Cu ₂ O-20% ZnO-50:50 C8/TEOS xerogel was showed to lower the bacterial count in the water after 21 days. This result indicate that both the quaternary ammonium and the copper additive are firmly sequestered in the solid film of the xerogel and that the anti-biofilm activity of these materials is not caused by leaching of toxic substances in the surrounding environment. Natural biofilm growth analysis. Experiment 1 (March 01 to March 22, 2017)

Blank 50:50 C8/TEOS 1:49:50 QAC/C8/TEOS

Biofilm thickness (μμ) 21,60 ± 4,08 22,87 ± 5,78 22,71 ± 7,83 Biofilm area coverage

41,92 ± 8,52 50,51 ± 8,82 28,80 ± 9,69* (%)

Cellular viability (%) 60,88 ± 12,79 76,15 ± 8,82 38,43 ± 9,06*

*Statistically significant difference from blank

[0174] Results from experiment #1 show that there is a significant difference between the blank control and the 1:49:50 QAC/C8/TEOS coating at the level of biofilm coverage area and cellular viability on the surface. Lower values (31.3% of coverage area and 36.9% of cellular viability) indicate an anti-biofilm activity of the xerogel. Confocal laser scanning microscopy images show a normal mature bacterial biofilm on the control glasses but both 50:50 C8/TEOS and 1:49:50 QAC/C8/TEOS coating stop the biofilm in the adhesion part of the process. Since there is no viable micro colony, these biofilms are not considered to be growing on the surface . Experiment 2 (March 31 to April 21, 2017)

0.1% Cu ₂ O 0.1% Cu ₂ O 30% Cu ₂ O-20% ZnO

Blank

0:50 C8 TEOS 0.1:49.9:50 QAC/C8 TEOS 50:50 C8/TEOS

Biofilm thickness

25,08 ± 7,08 23,27 ± 8,16 21,671 ±4,95

(Mm)

Biofilm area

23,54 ± 6,37 14,90 ± 6,38* 9,85 ± 4,65*

coverage (%)

Cellular viability

87,26 ± 4,34 51,38 ± 9,35* 28,36 ± 8,88*

(%)

*Statistically significant difference from blank

[0175] Results from experiment #2 show that the 30% Cu20- 20% ZnO 50:50 C8/TEOS coating forms a very potent anti-biofilm surface. Confocal laser scanning microscopy shows a total absence of bacterial activity on glass slides treated with this material. Results also show that there is a significant difference between the blank control and both 0.1% Cu ₂ 0- 50:50 C8/TEOS and 0.1% Cu ₂ 0- 0.1:49.9:50 QAC/C8/TEOS coatings at the level of biofilm coverage area and cellular viability on the surface, an indication of anti-biofilm activity. After three weeks, the microorganisms on the control glass slides were viable and the biofilm was getting mature. On the 0.1% Cu ₂ 0- 50:50 C8/TEOS surfaces, microcolonies were getting some form of structure even if cellular viability was low. For the 0.1% Cu ₂ 0- 0.1:49.9:50 QAC/C8/TEOS coating, images show that there is no viable micro colony and the biofilm is not considered to be growing on the surface .

Experiment 3 (April 05 to April 26, 2017)

0.1:49.9:50

Blank 1:49:50 C18/C8/TEOS

QAC/C8/TEOS

Biofilm thickness (μμ) 29,00 ± 8,66 21,53 ± 4,31 16,53 ± 2,80* Biofilm area coverage

61,62 ± 8,88 35,51 ± 8,09* 31,53 ± 9,89* (%)

Cellular viability (%) 58,27 ± 8,41 56,23 ± 8,83 63,25 ± 10,12

*Statistically significant difference from blank

[0176] Results from experiment #3 show that there is a significant difference between the blank control and the 0.1:49.9:50 QAC/C8/TEOS coating at the level of biofilm coverage area, an indication anti-biofilm activity. On the other hand, there is not much difference in biofilm maturity and in cellular viability on this surface. [0177 ] It is noteworthy that the 0.1% Cu ₂ 0- 0.1:49.9:50

QAC/C8/TEOS coatings is showing an important synergy between the action of the anti-fouling additive (copper (I) oxide) and the quaternary ammonium group. Indeed, the 0.1% CU ₂ O- 0.1:49.9:50 QAC/C8/TEOS coatings is notably more efficient than both the 0.1:49.9:50 QAC/C8/TEOS and the 0.1% Cu ₂ 0- 50:50 C8/TEOS coating regarding the biofilm area coverage and cellular viability on the surfaces.

[0178 ] Fouling release capacity. The amount of biofilm removed with a low pressure water jet (from a cleaning flask) was evaluated using the confocal laser scanning microscopy technique. After washing with deionised water, microscopy images show that virtually all biofilms present on these hydrophobic surfaces were removed. Images show that on the 0.1% Cu ₂ 0- 0.1:49.9:50 QAC/C8/TEOS and the 1:49:50 QAC/C8/TEOS coatings, all residual microorganisms are dead and will be incapable of growing a new biofilm.

Bacterial biofilm culture growth

Table 1 : Adhesion of mono species biofilm cultures on coated surfaces

Adhesion (%)

Coatings Vs Ph Sc Rd Pk

10% Cu20 - 50/50 C8/TEOS 68,87 95,35 67,76 89,15 46,31

20% Cu20 - 50/50 C8/TEOS 93,06 201,66 89,21 69,28 20,30

1% Copper thiocyanate - 50/50 C8/TEOS 83,84 85,16 40,65 86,95 45,78

5% Copper thiocyanate - 50/50 C8/TEOS 56,82 114,46 64,16 69,77 84,20

1% Zinc pyrithione - 50/50 C8/TEOS 0,00 0,00 0,00 15,51 0,00

5% Zinc pyrithione - 50/50 C8/TEOS 0,00 0,00 0,00 5,46 12,28

10% Ti02 - 50/50 C8/TEOS 46,09 71,92 83,40 71,65 88,90

20% Ti02 - 50/50 C8/TEOS 55,51 54,28 72,08 66,15 97,11

1% Zineb - 50/50 C8/TEOS 57,02 36,87 0,20 88,77 70,26

10% Cu20 + 0,1% zineb - 50/50 C8/TEOS 46,08 169,79 58,79 77,71 32,94

10% Ti02 + 0,1% zineb - 50/50 C8/TEOS 0,00 56,98 0,00 91,98 26,18

0,1/49,9/50 QAC/C8/TEOS 62,32 59,35 52,01 65,04 45,16

1/49/50 QAC/C8/TEOS 82,09 148,34 88,94 58,72 63,09

10% Cu20 - 1/49/50 QAC/C8/TEOS 51,50 37,72 95,77 81,32 44,26 5% Cu20 - 0,1/49,9/50 QAC/C8/TEOS 38,95 29,61 37,78 58,93 76,10

1% Econea - 50/50 C8/TEOS 52,48 15,57 0,00 34,24 9,38 % Cu20 + 0,1% econea - 50/50 C8/TEOS 71,92 64,12 88,61 92,81 79,52 % Ti02 + 0,1% econea - 50/50 C8/TEOS 41,39 0,19 9,05 67,15 67,79

10% Cu20 - 50/50 C3/TEOS 3,91 42,91 46,73 56,70 58,01

20% Cu20 - 50/50 C3/TEOS 0,01 33,64 17,38 61,44 39,26 % Copper thiocyanate - 50/50 C3/TEOS 36,00 66,63 101,36 96,92 62,34 % Copper thiocyanate - 50/50 C3/TEOS 29,81 46,22 77,33 77,63 61,97

1% Zinc pyrithione - 50/50 C3/TEOS 0,00 0,00 10,74 30,40 10,28

5% Zinc pyrithione - 50/50 C3/TEOS 0,00 2,16 12,90 17,50 0,04

1% Irgarol - 50/50 C8/TEOS 40,53 23,47 2,05 72,47 84,98 % Cu20 + 0,1% irgarol - 50/50 C8/TEOS 54,62 69,41 31,89 71,82 55,52 0% Ti02 + 0,1% irgarol - 50/50 C8/TEOS 59,53 120,12 25,95 98,50 107,27

10% Ti02 - 50/50 C3/TEOS 32,33 60,07 88,08 80,66 43,11

20% Ti02 - 50/50 C3/TEOS 41,02 40,52 100,05 41,41 86,17

1% Zineb - 50/50 C3/TEOS 45,60 8,87 25,96 31,53 38,07 0% Cu20 + 0,1% zineb - 50/50 C3/TEOS 28,70 30,41 0,19 43,06 39,29 0% Ti02 + 0,1% zineb - 50/50 C3/TEOS 50,73 54,09 80,64 28,46 22,11

1% Irgarol - 50/50 C3/TEOS 45,29 6,88 191,49 117,34 43,95 % Cu20 + 0,1% irgarol - 50/50 C3/TEOS 43,64 0,00 0,52 25,46 42,46 0% Ti02 + 0,1% irgarol - 50/50 C3/TEOS 95,41 11,20 99,87 80,09 64,11 1% Econea - 50/50 C3/TEOS 61,94 1,49 0,00 93,21 35,96% Cu20 + 0,1% econea - 50/50 C3/TEOS 27,31 39,29 38,10 0,94 23,27 % Ti02 + 0,1% econea - 50/50 C3/TEOS 68,03 0,12 125,64 44,14 49,96

50/50 C8/TEOS 80,45 138,22 109,95 51,23 148.62 ,1% Cu20 - 0,1/49,9/50 QAC/C8/TEOS 80,00 145,87 78,40 82,01 58,58

0,1% Cu20 - 50/50 C8/TEOS 56,13 119,32 65,34 76,76 145.29

10/40/50 TDF/C8/TEOS 84,24 164,54 88,05 73,45 119.16,1% Cu20 - 0,1/49,9/50 SiNH2/C8/TEOS 86,66 144,91 77,16 111,52 82.74

1% Fumed silica - 50/50 C8/TEOS 94,57 206,19 97,65 97,89 133.96

50/50 C8/TEOS (acetic acid) 71,05 125,61 95,56 86,65 107.40

50/50 C8/TEOS (cinnamic acid) 5,12 38,00 11,68 20,61 88.51

50/50 C8/TEOS (salicylic acid) 20,42 43,16 24,51 11,77 2,88

1/49/50 QAC/C3/TEOS 56,96 274,14 78,08 61,64 85.61

5% Cu20 - 0,1/49,9/50 QAC/C3/TEOS 23,43 111,93 35,06 50,93 45.600% Cu20 - 50/50 C8/TEOS (isopropanol) 96,27 118,76 100,00 90,78 26,84

30% Cu20 - 50/50 C8/TEOS (ethanol) 69,54 99,30 89,65 88,60 103.97

30% Cu20 - 50/50 C8/TEOS (octanol) 32,63 0,00 0,00 0,11 65.450% Cu20 - 50/50 C8/TEOS (no solvent) 36,46 93,06 46,83 38,99 54.29

30% Cu20 - 25/75 C8/TEOS 45,35 240,14 45,25 51,44 78,01

30% Cu20 - 10/90 C8/TEOS 39,72 221,80 45,05 52,40 7.61

30% Cu20 - 25/75 C3/TEOS 12,27 144,48 37,80 48,53 49.08 Vs = Vibrio splendidus 7SH W; Ph = Pseudoalteromonas haloplanktis ATCC 14393;

Sc = Shewanella colwelliana ATCC 39565; Rs = Roseobacter denitrificans ATCC

33942;

Pk = Planococcus kocurii ATCC 43650

Adhesions are expressed as percent adhesion according to the following equation:

(DO630nm biofilm treated / DO630nm biofilm control)* 100.

[0179 ] Results presented in table 1 show a range of antibiofilm activity from xerogel and biocide containing xerogel. Copper and titane salt offer moderate to good antibiofilm properties but zinc pyrithione was found to be extremely efficient in reducing the adhesion of the microorganisms on the xerogels, even when used in low concentrations. Organic antifouling compounds like irgarol and econea also impart a range of antibiofilm activity to the xerogel. Although most biocide containing xerogel present a range of antibiofilm actibity, our results have showed the presence of a hormesis effect in some cases, mostly with Pseudoalteromonas haloplanktis . The presence of fumed silica in the xerogel didn' t increased the antibiofilm activity of the surface but this additive can still be of use in other to fine tune the viscosity of the sol-gel solution. Some organic acids catalyst (used in the sol-gel preparation) like cinnamic acid and salicylic acid seem to increase the antibiofil properties of the corresponding xerogels. The nature of the sol-gel solvent also seem to play a role in the activity of the resulting xerogel. This is probably due to a variation of the surface physical characteristics (topography, elasticity, etc.) of the xerogel that is formed when the solvent evaporate. Finally, it was showed that C3 containing xerogels are generally more potent than the C8 equivalent materials . This fact can be explain by the difference in the modulus of the xerogel surface formed.

[0180 ] While the disclosure has been particularly shown and described with reference to specific embodiments (some of which are preferred embodiments), it should be understood by those having skill in the art that various changes in form and detail may be made therein without departing from the present disclosure .