SOLVATO-CONTROLLED DOPING OF CONDUCTING POLYMERS

Silver(I) is employed to dope poly(3-alkylthiophenes) (P3ATs) and othe r conjugated polymers. Solutions containing silver(I) salts and P3ATs, which usually undergo spontaneous reaction, doping, and precipitation , were stabilized using coordinating ligands that modify the reduction potential of the Ag(I) species. Upon removal of the coordinating liga nd, spontaneous oxidative doping of the polymer occurred. Uniform elec tronically conducting films were thus obtained by simultaneous evapora tion of both solvent and Ag(I)-coordinating ligand-a process termed '' solvato-controlled doping''. Doping was observed with a variety of sil ver(I) salts consisting of relatively electronegative counterions, whe reas a series of poly(3-alkylthiophenes) possessing increasing head-to -head dyad content showed a decreasing tendency to undergo Ag(I)-dopin g due to the increasingly positive oxidation potential of the polymer. Solvato-controlled doping of polyaniline and poly(3-methoxythiophene) with Ag(I) is also described, thus demonstrating the applicability of this approach to other conducting polymer systems.