Conductive polymer coatings for three dimensional substrates

Abstract

The present invention generally relates to compositions and methods for the preparation of conductive polymer coatings, and methods for application of the coatings to three-dimensional substrates.

What is claimed is: 
     
         1 . An electrically conductive polymeric coating on a substrate, wherein the electrically conductive coating is derived from a coating precursor composition comprising:
 a conductive polymer component comprising poly(3,4-ethylenedioxythiophene) and a primary counterion comprising repeat units, wherein one or more of the repeat units have a negatively charged functional group;   a secondary doping agent;   a crosslinking agent selected from the group consisting of 3-(trimethoxysilyl)propyl methacrylate, 3-(trimethoxysilyl)propyl acrylate, vinyltrimethoxysilane, allyltrimethoxysilane, tetrakis(trimethylsilyloxy)silane, poly(ethylene glycol) divinyl ether, and a branched trialkyloxy silane;   a surfactant component; and   a flexibility enhancer comprising poly(acrylamide-co-acrylic acid), polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, or a combination thereof.   
     
     
         2 . The coating of  claim 1  wherein the electrical resistance of the coating increases by no greater than 50% after 600 flexing cycles when the coating is applied to a substrate having an outer diameter of 0.25 inches and each cycle comprises flexing the coated substrate about a bend radius of 1.25 inches. 
     
     
         3 . The coating of  claim 1  further comprising a conductive filler comprising metal particles, carbon black, carbon fiber, graphite, graphene, carbon nanotubes, carbon fiber silicon, silicon particles, or a combination thereof, wherein the conductive filler is present in the electrically conductive polymeric coating in an amount sufficient to reduce the contact resistance of the polymeric coating, and wherein the conductive filler is present in the coating precursor composition in a concentration of no more than about 25% of the composition on a weight per volume basis. 
     
     
         4 . The coating of  claim 1  wherein the primary counterion comprises a negatively charged functional group comprising a phosphate group, a phosphonate group, a sulfamate group, a carboxylate group, a sulfate group, a sulfonate group, or a combination thereof. 
     
     
         5 . The coating of  claim 1  wherein the primary counterion comprises polyvinyl sulfonate, polystyrene sulfonate, polyallyl sulfonate, polyethyl acrylate sulfonate, polybutyl acrylate sulfonate, polyacryl sulfonate, polymethacryl sulfonate, poly-2- acrylamide-2-methylpropane sulfonate, polyisoprene sulfonate, polyvinyl carboxylate, polystyrene carboxylate, polyallyl carboxylate, polyacryl carboxylate, polymethacryl carboxylate, poly-2-acrylamide-2-methylpropane carboxylate, polyisoprene carboxylate, polyacrylates, polyglutamates, polydopamines, sulfonated poly ether ether ketones (S-PEEK), sulfonated polyurethanes, or a combination thereof. 
     
     
         6 . The coating of  claim 5  wherein the primary counterion comprises polystyrene sulfonate. 
     
     
         7 . The coating of  claim 1  wherein the coating precursor composition comprises poly(3,4-ethylenedioxythiophene):polystyrene sulfonate in the form of aqueous dispersion. 
     
     
         8 . The coating of  claim 1  wherein the coating precursor composition further comprises an organic solvent. 
     
     
         9 . The coating of  claim 1  wherein the secondary doping agent comprises a low volatility polar solvent selected from the group consisting of ethylene glycol, sorbitol, glycerol, dimethylsulfoxide, N,N-dimethylformamide, erythritol, 2-nitroethanol, methoxyphenol, N,N-dimethylacetamide, N-methylpyrrolidone, succinimide, propylene glycol, and combinations thereof. 
     
     
         10 . The coating of  claim 1  wherein the surfactant component comprises one or more anionic surfactants selected from the group consisting of alkylbenzenesulfonic acids and salts thereof, organosulfates, carboxylates, and natural fatty acids and salts thereof. 
     
     
         11 . The coating of  claim 10  wherein the surfactant component comprises dodecylbenzenesulfonic acid or sodium dodecyl sulfate. 
     
     
         12 . The coating of  claim 1  wherein the coating precursor composition further comprises a monomer additive comprising one or more methacrylate, acrylate, acrylamide, or vinyl based monomers. 
     
     
         13 . The coating of  claim 1  wherein the coating precursor composition further comprises a stabilizer selected from the group consisting of 2,2,6,6-tetramethyl piperidine and its derivatives, benzophenones, benzofuranones, oxanilides, p-phenylenediamines, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, ethylene diurea, hindered phenols, aromatic amines, benzotriazoles, hydroxyphenyltriazines, and combinations thereof. 
     
     
         14 . The coating of  claim 1  wherein the coating precursor composition further comprises a swelling agent, and wherein the swelling agent comprises a polar solvent. 
     
     
         15 . A cylindrical tube electrode comprising:
 a cylindrical tube comprising an inner lumen and an outer surface,   and an electrically conductive polymeric coating adhered to the outer surface,   wherein the electrically conductive polymeric coating comprises one or more conductive layers,   and wherein one or more of said conductive layers comprises the electrically conductive polymeric coating of  claim 1 .   
     
     
         16 . The coating of  claim 1  wherein the coating precursor composition comprises: the crosslinking component in a concentration of from 0.1% to 10% of the precursor composition on a weight per volume basis; the secondary doping agent in a concentration of from 1% to 40% of the precursor composition on a weight per volume basis; and the surfactant component in a concentration of from 0.01% to 5% of the precursor composition on a weight per volume basis.