Critical dependency of the conductivity of polypyrrole and polyaniline films on the hydrophobicity/hydrophilicity of the substrate surface

The conductivity, electronic properties and morphology of polypyrrole and polyaniline films deposited from aqueous solutions of the polymerizing monomer differ greatly according to whether they are deposited on a hydrophobic or hydrophilic substrate surface. For each polymer the conductivity of the film deposited on a hydrophobic substrate is ~104 greater than that of the film of approximately the same thickness deposited on a hydrophilic surface. Films of increasing thickness exhibit a “memory effect” induced by the nature of the original substrate surface.