Regensburg 2002 – wissenschaftliches Programm
SYPF 2.7: Poster
Donnerstag, 14. März 2002, 09:00–18:00, Poster B
Microdomain structure and dynamics of self-dewetting in thin films of polystyrene-block-poly(ethylene propylene) — •A. Horvat, A. Knoll, R. Magerle, and G. Krausch — Physikalische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
The structural development of polystyrene-block-poly(ethylene propylene) (PS-PEP) thin films with 28 weight per cent PS has been studied as a function of film thickness, temperature and annealing time. Above the polystyrene (PS) glass transition temperature various self assembled structures are formed depending on treatment. Tapping Mode AFM investigations of spin cast samples reveal a stripe like pattern at the film surface corresponding to the bulk structure of cylindrical microdomains. Upon annealing at 413 K a transition to irregular structures with dimensions much larger than the microdomain spacing occurs. At longer time scales polymer droplets form and move spontaneously across the surface showing some new pathway of dewetting. This phenomenon was followed in situ by hot stage Tapping Mode AFM. The phenomenon is believed to be caused by a delicate balance between the surface and volume contributions to the effective interface potential of the confined polymer film.