Highly Conducting Graphite Film Prepared by Pyrolysis of Polymers

Highly conducting graphite film has been prepared by pyrolysis of aromatic polymers up to 3000°C.Graphitization and the orientation of ab-plane in the pyrolyzed polymers are discussed in relation to the melecular orientation in pristine films, especially that of Poly (p-phenylene vinylene), PPV.Biaxially strectched PPV film was pyrolyzed to give highly oriented graphite in keeping the form. Conductivities of the graphite film reached104 S/cm and105 S/cm by intercalation, which are comparable to those of the highly oriented pyrolytic graphite (HOPG).Raman spectrum analyses indicate that the film is converted into pure graphite above2750°C.X-ray diffraction analyses and scanning electron micrographs for the stretched PPV and the pyrolyzed products suggest that the biaxial stretching induces planer orientation in PPV film and facilitates its graphitization and the orientation of the ab-plane. Aromatic polyimide film was also converted into highly oriented graphite and showed104 S/cm after pyrolysis at 3000°C, while aromatic polyamideimide and polyamide showed103 S/cm at most after pyrolysis at the temperature.