Lamellar structures formed in spin-cast blends of insulating and conducting polymers

Distribution of polyaniline doped by camphorsulfonic acid, blended with polystyrene of different molecular weight and spin-cast from chloroform into (50–400 nm thick) films, was examined using secondary ion mass spectrometry (SIMS). Strong polyaniline segregation to the Au substrate was observed to be accompanied by depletion region or, for thicker films, by concentration oscillations. Segregation and substrate-directed phase separation, effective during solvent removal, form lamellar film structures.