Effect of Three Arm Polystyrene on Polystyrene Film Stability

This research studied ways to increase the stability of a polymer thin film with a thickness of approximately 10 nm. Our system consisted of a polystyrene (PS) thin film filled with three arm polystyrene (TAP) as additives. Formation of dewetting was investigated by atomic force microscopy and optical microscopy which showed that complete dewetting of the pure PS film occurs after being annealed at 120 oC for 5 h. The dewetting dynamics were dramatically suppressed when a small amount of TAP polymer was added into the PS thin film. We hypothesize that the nitrogen atom in the TAP polymer provides dipolarity between the polymeric thin films and the substrate followed by an increase in the interfacial interaction of the TAP/PS thin films, which in turn leads to increased film stability. However, if the concentration of TAP is too high, this leads to phase separation of the thin films. We also observed that the amount of TAP within the PS thin film largely affected the efficiency of inhibiting dewetting. This method could be utilized for the study of the mechanism in a blended polymer film.