Nanofilms Based on Vapor Deposition of Polymerized Polypyrrole and its Characteristics

Abstract

Nanofilms of polypyrrole (PPy) were prepared chemically by vapor deposition polymerization (VDP). It was found from the analysis of the morphological structure by atomic force microscopy that ultra thin films of PPy with thicknesses between 30 and 80 nm could be formed by VDP as well as by casting. These thin films showed surface features of highly ordered structural regularity. The surface resistance of PPy films more than 60 nm thick was enhanced up to 10 3 Ω/□ and light transmittance was increased up to 90% in the case of a film less than 40 nm thick. From the electronic absorption and Raman scattering spectra, it was found that the charged domains (chemical defects) dispersed in polymer chains of PPy nanofilms are due more to bipolarons than to polarons.