Molecular-Level Processing of Conjugated Polymers. 3. Layer-by-Layer Manipulation of Polyaniline via Electrostatic Interactions

Abstract

Multilayer thin films comprised of sequentially adsorbed layers of partially doped polyaniline and a polyanion, sulfonated polystyrene, were fabricated via the use of a simple layer-by-layer molecular-level processing scheme. Using this simple multilayer polymer adsorption process, uniform thin films of polyaniline in the 40−600 Å thickness range were readily fabricated onto a variety of different substrates. Doping of these films with strong acids such as HCl and methane sulfonic acid results in electrically conductive thin films with conductivities comparable to those obtained with spin cast films (0.5−1.0 S/cm). The adsorption process used to fabricate the films was found to be driven primarily by the electrostatic attractions developed between the partially doped chains of polyaniline (polycation) and the negatively charged chains of the polyanion.