ELECTRICAL-CONDUCTIVITY OF HIGHLY ORGANIZED LANGMUIR-BLODGETT-FILMS OF PHTHALOCYANINATO-POLYSILOXANE

The electrical properties of phthalocyanine-polysiloxanes were investi gated at room temperature. Polymers were deposited in LB films with hi gh in-plane orientational anisotropy, allowing for a directional depen dence of the conductivity to be measured. It was found that the conduc tivity parallel to the preferred orientation of the polymer chains is higher than the conductivity perpendicular to this direction. The orie ntational anisotropy could be manipulated by using different molecular weight polymers, and by annealing of the polymer films. Lower molecul ar weight materials showed the least orientational anisotropy, and ann ealing increased the orientational anisotropy. Using these strategies to intentionally alter the orientational anisotropy, corresponding cha nges in the conductivity could be detected. It was concluded that the charge transport was fastest along the polymer chains. Interchain char ge carrier hops are assumed to be rate limiting, with the process faci litated by end to end orientation between polymer chains.