Abstract: The chemical structure of mica surface treated with ethylene plasma of radio frequency and plasma polymerization reaction of ethylene in the presence of mica were studied by means of elemental analysis, GC-MS, PGC and ESR. It shows that the mica particle is wrapped by a dozens-of-angstroms-thick film, the chemical structure of which is the same as that polymerized in the absence of mica. Using SEM, we found for the first time the star fish-like morphology of plasma polymerized film. The "star fish" expands with the plasma treating time while its shape remains unchanged. The contact angle of water on mica surface treated by different methods at various conditions was measured. The results indicate that hydrophobicity of mica surface resulting from ethylene plasma treatment is greater than that both from Ar Plasma treatment and from silicane or titanate coupling agents.

Key words: Plasma polymerization, Mica, Surface structure, Surface properties