Electrically conducting poly[3-(omega-hydroxyalkyl)thiophenes]

A series of poly[3-(omega-hydroxyalkyl)thiophenes] was synthesized by chemical oxidative polymerization using FeCl3 and characterized by FT-IR, thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Upon doping with iodine the polymers attained electrical conductivities of between 0.5 and 38 S cm(-1). Electrical conductivities of doped samples were found to increase with alkyl chain lengths, being optimum for the octyl pendant moiety. Thereafter, the conductivity decreased, as the doping and dedoping for the polymers became more difficult. Increasing the hydrocarbon chain length of the pendant substituent also resulted in decreased thermal stability of the polymers. XPS results showed that some C-OH groups in the polymers were oxidized to C=O in the polymerization process.