Synthesis and properties of a mechanically strong poly(bithiophene) composite polymer containing a polyelectrolyte dopant

Electrochemical polymerisation of 2,2'-bithiophene (BT) in the presence of a sulfated poly(beta-hydroxyether) (S-PHE) yielded thin films that displayed excellent mechanical properties. Tensile strength measurements gave breaking strains ranging from 98 to 128 MPa for free standing poly(bithiophene)/sulfated poly(beta-hydroxyether) (PBT/S-PHE) films, while scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies on this material revealed a uniform surface morphology, with an average distance between peaks and valleys on the surface of 1 mu m. Four point probe measurements performed on free standing PBT/S-PHE indicated that they were semiconducting, with conductivities ranging from 0.2 to 0.8 S cm(-1). In propylene carbonate solution PBT/S-PHE was electroactive, with overoxidation commencing at approximately +1.35 V. Although electroinactive in aqueous solutions, PBT/S-PHE-coated electrodes were able to be used to examine the aqueous electrochemistry of electroactive solutes, such as cupric ion and ferrocyanide. All results indicate that PBT/S-PHE composite films and films are interesting candidates for a number of applications. (C) 2000 Elsevier Science S.A. All rights reserved.