Thin polymeric films are increasingly being utilized in diverse technological applications and it is crucial to have a reliable method to characterize the stability of these films against dewetting. The parameter space that influences the dewetting of thin polymer films is wide (molecular mass, temperature, film thickness, substrate interaction) and a combinatorial method of investigation is thus suitable. We thus construct a combinatorial library of observations for polystyrene (PS) films cast on substrates having orthogonal temperature and surface energy gradients. Our observations indicate that the polymer surface tension can be appreciably modified in thin polymer films from their bulk counterparts so that bulk surface tension measurements cannot be used to estimate the stability of ultrathin films. We were also able to obtain a near-universal scaling curve describing a wetting-dewetting transition line for polystyrene films of fixed thickness.
Pub Type: Journals
combinatoric method, surface tension, ultrathin films, wetting-dewetting transition line