Surface modification of a contact lens co‐polymer by plasma‐discharge treatments

XPS and contact angle measurements have been used to investigate the surface modification of an alkyl‐acrylate/polysiloxane co‐polymer by plasma‐discharge treatments. The improved wettability brought about by the plasma treatments is shown to result from the oxygenation of the surface layers and the conversion of the polysiloxane component to a silica‐like phase. By analysis with MgKα, AlKα, and AgLα induced XPS this oxygenation is shown to decrease with depth. The total thickness of this altered zone has been estimated by comparing these results with data from argon ion bombardment studies.