Influence of Relative Humidity during Film Formation Processes on the Structure of Ultrathin Polymeric Films

Abstract

Film formation processes of ultrathin films of a curable model polymer system in the presence of a metallic substrate were studied. The structure of prepolymerized films strongly depends on the relative humidity during the spin-coating process. With increasing atmospheric humidity, typical defect structures were observed which never healed during full curing. A mathematical simulation shows that condensation of water forming liquid drops can be excluded as source of holes in the films. We propose that these defects are caused by physisorbed water layers on the substrate surface resulting in a dewetting of the polymer.