Correlation of surface hydrophilicity and surface static properties in epoxy/glass fibre after plasma treatment

In this study, which was performed to identify a degradation mechanism in macromolecular insulating material, the contact angle, surface potential decay, surface resistance rate and XPS analysis were compared after exposure of fibre-glass-reinforced polymer (FRP) laminate to plasma discharge. In the case of the contact angle, the surface of the untreated specimen showed weak hydrophobicity at 73degrees. However, the contact angle was decreased to 20degrees in the plasma-treated specimen. In the case of chemical changes arising from plasma treatment, carboxyl radicals were generated mainly in the plasma-treated surface, which was rapidly changed to a hydrophilic surface. In the corona potential decay study to determine the electrical changes of the surface, positive charges were decreased rapidly when compared with negative charges, leading to a negative surface for the untreated specimen. However, in the case of the hydrophilic surface, a lot of carboxyl radicals (-COO) acting as positive polarity were generated, resulting in a positive surface. Owing to such a positive surface, the charges of applied negative polarity were decreased rapidly. Copyright (C) 2002 John Wiley Sons, Ltd.