Solid-state synthesis of conductive polymer PEDOT whiskers

Abstract

A long-standing goal in synthetic polymer chemistry is to synthesize polymers with a well-defined microstructure with desired properties. We have reported here a novel synthesis method to produce conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) whiskers in vapor phase polymerization, in which the monomer vapor diffuses into the oxidant matrix to initiate polymerization. Pencil-like whiskers are projected vertically to the surface of the PEDOT-stuffed film. The whiskers are of 0.5–1.0 µm in width and 5–10 µm in length. It is speculated that the polymerized PEDOTs builds internal compressive stresses in the oxidant matrix. To compensate for the stress, the reacted oxidant molecules along with the entangled PEDOTs are being reorganized to a lower internal energy state, thus leading an anisotropic whisker growth. Crystallites formation of oxidant acts as a driving force and the crystal structure of the PEDOT molecules define the shape of the whiskers. This new route of polymer whiskers formation is simple and cost-effective. Importantly, the PEDOT whiskers can be produced onto a large area of any surface.