Highly conductive and semitransparent free-standing polypyrrole films prepared by chemical interfacial polymerization

Abstract

Chemical interfacial polymerization is a facile and effective way to synthesize large-area free-standing polypyrrole (PPy) films. Unfortunately, the conductivities of the PPy films prepared by ordinary chemical interfacial polymerization are generally very low. In this work, large-area, highly conductive and semitransparent free-standing PPy films are prepared by chemical interfacial polymerization at the interface of cyclohexane/water at a low monomer concentration and/or at a short reaction time. PPy films with a thickness ranging from nanometers to submicrons can be obtained by adjusting the monomer concentration and reaction time. The conductivity of the PPy films is up to 560 S cm⁻¹. And the PPy films exhibit moderate transparency with a transmittance up to 31%. FTIR, Raman and XRD characterizations show that the PPy films have very similar polymer backbones and aggregated structures. XPS analyses indicate that the PPy films are doped with both p-toluenesulfonic acid (PTS) and Cl⁻. The high doping levels and the compact and smooth surface morphologies are the main reasons for the high conductivities of the PPy films.