P o l y p y r r o l e / p o l y ( s t y u~o~~) (PP/PSS) molecular composites have been synthesized by the electrochemical polymerization of pyrrole in the presence of sodium poly(styrenesu1fonate) (PSS-Na+). Their synthesis and charge transport properties have been investigated by a combination of electrochemical and gravimetric techniques using the Electrochemical Quartz Crystal Microbalance (EQCM). Electropolymerization in water at 0.8 V vs Ag/AgCI yields a partially hydrated polymer complex with sulfonate dopant anions from PSS. Mass transport is found to be cation specific, as expected for a composite system, with the polyelectrolyte chains physically entrapped within the polymer membrane. Frequency responses of the EQCM during electrochemical switching are found to increase with increasing electrolyte cation mass as Li+ r Na+ C Cs+ C Et4N+ C Bu4N+. Chronogravimetric and chronocoulometric analyses of PP/PSS-Na+ yield apparent diffusion constants, Dm between lo4 and lo-" cm2 s-I for mobile hydrated Na+ species. Though the determinations of these values are complicated by the exact determination of the concentration of electroactive sites (Co*), it is evident that reductive transport processes are faster than oxidative transport processes during switching. IntroductionThe electrochemical preparation of electrically conductive blends and composites of polyheterocycles, with a variety of carrier polymers has led to a new class of multicomponent materials with controllable electrical, electrochemical, and mechanical properties. The ultimate properties result from the intrinsic properties of both the polyheterocycle, and the carrier polymer, along with specific interactions between the two polymers. A number of composites of polyheterocycles with matrix supporting polymers and polyelectrolytes have appeared in the literature. Early work on these systems involved the electrochemical polymerization of a heterocycle within a predepasited, solvent-swollen thermoplastic polymer matrix on an electrode surface. Several systems have been prepared in this manner, including composites of polypyrrole with poly(viny1 chloride),2 poly(viny1 al~ohol),~ polystyrene,& poly-(methyl methacrylate),% and vinylidene chloride-vinyl chloride copolymers.& This method has been improved by saturating the supporting polymer matrix with an electrolyte prior to deposition and subsequent electropolymerization.'A common problem encountered in films prepared by this method is an irregular conductivity across the thickness of the film as a result of the polymerization originating at the electrode/matrix interface, which then proceeds outward through the film as the monomer diffuses in. These problems were only partially alleviated by the electrolyte-doped host matrix.Composite films of poly(3-methylthiophene) with poly(methy1 methacrylate) and poly(viny1 chloride) have been prepared by using a simple one-step procedure involving electropolymerization onto a metallic electrode from a solution containing 3-methylthiophene, supporting electrolyte, an...

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We report experimental studies of the statics and dynamics of diffusion-limited polymerization. The fractals obtained were produced electrochemically from neutral precursors, and have a Hausdorff dimension of 1.74 ±0.03. The width of the active growth zone increases at the same rate as the fractal radius. The chemical dimensionality determined by scale-dependent conductivity measurement is 0.96 ±0.04. This implies a value for the spectral dimensionality of 1.26 ±0.04.