Synthesis and properties of electrically conducting polytriphenylamines

Novel conducting polymers consisting of triphenylamine repeat units, i.e., poly(4,4′,4″-triphenylamine) (PTPA-NET), poly(4,4′-triphenylamine) (PTPA-H) and poly(4,4′-(4″-methyl)triphenylamine) (PTPA-ME), were synthesized by nickel-catalyzed polycondensation of Grignard reagents from the corresponding trihalogeno- or dihalogenotriphenylamine derivatives. PTPA-NET is insoluble and has good thermal stability. PTPA-H and PTPA-ME are soluble and can be easily processed. A thin film of PTPA-H can be made insoluble by an iodine-doping cross-linking reaction. These polymers have very stable chemically and electrochemically p-doped (oxidized) states and their electrical conductivity is in the order of 1 S cm −1 with iodine doping. With electrochemical doping, the maximum conductivity was observed at a medium doping level. The oxidation potentials of the polymers range from 0.8 to 1.0 V versus Ag/AgCl.