Conductive characteristics of radical-bearing polythiophenes using a microcomb-shaped electrode

The electric conductivity of π-conjugated and radical-bearing polymers, i.e., polythiophenes bearing pendant galvinoxyl and phenoxyl radical groups, was measured using a microcomb-shaped electrode. The electric conductivity was found to be enhanced by the radical content in the polymer. The infrared (IR) and Raman spectroscopies suggested a structural change from an aromatic form to a quinoid one in the polythiophene backbone by the phenoxyl radical generation. The effect of the pendant galvinoxyl. radical's unpaired electron on the electric conductivity of the polythiophene was discussed by comparing the conductivity of a radical-bearing polystyrene and a polythiophene mixed with low-molecular radical molecules.