Structural, mechanical, and electrical properties of electropolymerized polypyrrole composite films

Electrochemical polymerization of pyrrole in a solution containing dissolve d poly(vinyl alcohol) (PVA) produces a homogeneous, free-standing, flexible , and conductive polymer film. The films were characterized using infrared spectroscopy, wide-angle X-ray diffraction analysis, and scanning electron microscopy. The appearance of standard and some new absorption bands for po lypyrrole (PPy) and PVA confirms the composite formation. The mechanical pr operties of conducting PVA + PPy films were studied and found to be improve d with respect to the control PPY films. The electrical conductivity of the PVA + PPy films was measured by using standard four-and two-probe methods. The conductivity of the films was found to depend on the pyrrole content. These conducting composites were further used as gas sensors by observing t he change in current with respect to ammonia gas. It was observed that the current decreases when these composites were exposed to ammonia gas. (C) 20 01 John Wiley & Sons, Inc.