p Conduction in Organic Polymers

A polyurethane was synthesized from bi- and tri-functional isocyanates and N,Ns-bis(β-hydroxyethyl)-p-dimethylaminoaniline (BHDA) as hydroxy compound. In this polyurethane BHDA acts as electron donor and can be doped with bromine such that its conductivity increases as a function of the concentration by several orders of magnitude, compared with the undoped polymer. On the basis of spectroscopic measurements, of measurements of the Seebeck coefficient, and of the found concentration dependence, conductivity is shown to be due to holes.