Surface properties of PAN-based carbon fibers tuned by anodic oxidation in different alkaline electrolyte systems

High modulus carbon fibers were anodic oxidized in various alkaline electrolyte systems. The success of the modification was proved by contact angle measurements. The fiber surface tension was calculated from the measured contact angles using the harmonic mean method. With the exception of one electrolyte system, all in alkaline electrolytes modified carbon fibers showed an increased fiber surface tension. The increased fiber surface tension is due to the increased number of oxygen containing surface groups detected by energy dispersive X-ray microanalysis EDX.. Anodic oxidation causes a roughening of the fiber surfaces observed by scanning electron microscopy SEM.. Cyclo-voltammetric investigations give an possible mechanism of the anodic oxidation in alkaline electrolytes. q1999 Elsevier Science B.V. All rights reserved