Surface Modification of Carbon Fiber with Tetrafluoromethane Plasma

Abstract

Surface modification of carbon fiber by cold plasma of tetrafluoromethane was investigated.PAN-based and pitch-based carbon fibers were used. Plasma treatment was carried out by high-frequency discharge in tetrafluoromethane. The surface of carbon fiber was modified to be hydrophobic by treatment. The carbon fiber underwent heat-treatment or immersion in water, after which stability of the fluorine introduced was examined by measuring the contact angle with water, fluorine content, and estimating F/C in ESCA spectra.
The results revealed the following three types of the fluorine introduced by plasma treatment: (1) covalent bond type, insoluble in water and stable to heat, (2) layer interstitial type, insoluble in water and unstable to heat, (3) adsorption type, spluble in water and unstable to heat.