Surface Characterization of Carbon Fibers Exposed to 5 eV Energetic Atomic Oxygen Beam Studied by Wetting Force Measurements

Abstract
Changes in contact angle hysteresis and surface free energy of carbon fibers due to the irradiation of 5 eV energetic atomic oxygen beam were investigated. Atomic oxygen with kinetic energy of 5 eV was used in order to simulate the low earth orbit. Contact angle hysteresis in carbon fibers became larger with respect to the fluence of atomic oxygen. Auger electron spectroscopic analysis shows that the hysteresis of the contact angle is proportional to surface oxygen concentration as well as the polar component of surface free energy. Since adsorbed oxygen or the surface functional group plays an important role in the hysteresis, it is clear that the carbon fiber surface was destroyed due to the attack of atomic oxygen.