Effects of oxygen plasma treatment power on surface properties of poly( p-phenylene benzobisoxazole) fibers

Abstract

The effects of oxygen plasma treatment power on surface properties of poly( p-phenylene benzobisoxazole) (PBO) fibers were investigated. Surface chemical composition, surface roughness and surface morphologies of PBO fibers were analyzed by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. Surface free energy of the fibers was characterized by dynamic contact angle analysis (DCAA). The results indicated that the oxygen plasma treatment introduced some polar groups to PBO fiber surfaces, enhanced surface roughness and changed surface morphologies of PBO fibers by plasma etching and oxidative reactions. The polar groups and surface free energy of PBO fibers were significantly improved by the oxygen plasma treatment when the plasma treatment power was lower than 200 W. However, these two parameters degraded as the plasma treatment power went up to 300 and 400 W. PBO fibers were notably roughened by the oxygen plasma treatment. Surface morphologies of the fibers became more complicated, and surface roughness of the fibers enhanced almost linearly with the plasma treatment power increasing.