Formation of a Flexible Graphite Film from Poly(acrylonitrile) Using a Layered Clay Film as Template

A graphite film was prepared from poly(acrylonitrile) by a template carbonization method using layered clay film. Poly(acrylonitrile) was first carbonized in the two-dimensional opening between the lamellae of the clay film and the resultant clay/carbon film was subjected to HF treatment in order to remove the clay framework. Then the film was further heattreated up to 3000 °C. During the heating process, the fluoride residue produced in the HF treatment was vaporized and a graphite film was left. The original clay film and the resulting graphite film were characterized with a scanning electron microscope and an X-ray diffractometer. Furthermore, several physical properties such as the electrical resistivity and mechanical strength of the graphite film were investigated. It was found that the morphology and microstructure of the graphite film strongly depend on the microtexture of the original clay film used as a template. The most notable feature of this graphite film is its peculiar flexibility, which is not found in other graphite films. The origin of such flexibility was discussed in relation to the microstructure of the graphite film.