The effect of microwave plasma treatment on the surface energy of graphite as measured by inverse gas chromatography

The surface energy characteristics of natural graphite were modified by various microwave (2,4 GHz) plasma treatments (n-butyl alcohol, ammonia and n-butyl amine), and measured using inverse gas chromatography (I.G.C.), according to a new analytical method. The treatments were carried out indirectly (by placing the samples next to the microwave cavity) on natural graphite powders (150-250 μm) used either "as received" (GI) or after heat treatment at 800°C under argon (G II). While significant increases of both London dispersive component and expected acid-base character could thus be induced on G II, the changes are much less pronounced on G I, which is probably protected by some adsorbed contaminant film.