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PO: Polymerphysik

PO 2: Dünne Filme und Grenzfl
ächen II

PO 2.2: Talk

Tuesday, March 2, 1999, 11:00–11:20, HS 19

Influence of blend composition on phase separation and dewetting of thin polymer blend films — •P. Müller-Buschbaum, J. S. Gutmann, and M. Stamm — Max-Planck-Institut f"ur Polymerforschung, Ackermannweg 10, D-55128 Mainz (Germany)

The surface morphology of thin polymer blend films of deuterated polystyrene (dPS) and polyparamethylstyrene (PpMS) was investigated with scanning force microscopy (SFM) right after preparation and during annealing. Information about the density profile perpendicular to the sample surface is gained with neutron reflectivity measurements. Right after preparation dPS segregates to the air interface, while during annealing at a temperature above the glass transition temperature of both polymers with phase separation and dewetting PpMS builds up a top layer towards the surface. Depending on blend composition and annealing time different surface topographies (extremely smooth, flat films, small very shallow holes in an uniform film, homogeneous films with an enlarged surface roughness and various droplet patterns) are evolving. The examined film thicknesses are below a critical thickness and composition fluctuations directed normal to the surface are suppressed. The surface morphology is controlled by an interplay between phase separation and dewetting [1].

[1] P. Müller-Buschbaum, S. A. O’Neill, S. Affrossman, M. Stamm, Macromolecules 31, 5003 (1998)