The manufacture and properties of polyaniline nano-films prepared through vapor-phase polymerization

We succeeded in the chemical preparation of nano-level thick polyaniline (PANI) emeraldine salt films on plastic substrate by an in situ vapor-phase deposition (VDP) polymerization method under ambient conditions, using a self-assembly method which is unprecedented. Homogeneous conductive PANI thin films were uniformly fabricated at nano-level thickness (20-100 nm), but their morphologies could grow as polycrystalline grains of a highly ordered structure, depending on the deposition conditions. The grain size was also controlled between 30 and 100 mu m depending on the deposition time/temperature. The surface resistance of PANI films was enhanced up to 10(4) Omega/square with crystallization and light transmittance was increased up to 90% in the case of a film less than 30 nm thick. A typical spectrum for the oxidized PANI, the emeraldine salts form, showing pi-pi* transition and a polaron lattice were observed by UV-visible/IR and infrared /Raman spectroscopy. (c) 2007 Elsevier B.V. All rights reserved.