Composite LB films of copper octabutoxy phthalocyanine and polyimide

Abstract

Composite LB films of copper octabutoxy phthalocyanine (Cu-obo-Pc) and polyimide from polyamic acid alkyl amine salt have been deposited. The multilayers were formed from mixed Langmuir films and by alternate layer deposition. Analyses were by polarised UV–visible spectroscopy and X-ray diffraction. The phthalocyanine component retained its order in the matrix even after the composite was thermally imidised. The orientations of the chromophore in the alternating films were similar to that of the pure phthalocyanine films. However, in the mixed films, the macrocyclic ring changed its position from an almost flat orientation on the substrate surface to one with a smaller inclination to the substrate surface normal. It is suggested that the change in orientation is due to stresses induced by thermal imidisation which is accompanied by loss of the alkyl amine chain from polyamic acid alkyl amine salt.