SCANNING FORCE MICROSCOPE STUDIES OF LANGMUIR-BLODGETT POLYANILINE THIN-FILMS

Thin films of electrically conductive polyaniline were prepared using the Langmuir-Blodgett (LB) technique. Both single-layer and multilayer films were prepared using various surface pressures and dipping speed s. The resulting film microstructures were then studied using scanning force microscopy. Z-type deposition was observed, with high-quality s ingle layers of flat polyaniline platelets being formed at dipping spe eds of 1 mm min(-1) and surface pressures near 10 mN m(-1). Lower surf ace pressures resulted in incomplete layers, while much higher surface pressures resulted in clumps of polyaniline bundles in the finished f ilms. The fabrication of polyaniline films composed of hat platelets u sing the Langmuir-Blodgett technique as opposed to films composed of t he more common clumped bundles as seen in chemically cast or evaporate d films, results in finished films of much greater smoothness and stru ctural homogeneity. In all cases, the conductivity of protonated LB fi lms was lower than free-standing films cast from polyaniline-NMP solut ions.