Leipzig 1999 – wissenschaftliches Programm

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PO: Polymerphysik

PO 6: Poster: Dünne Filme und Grenzfl
ächen

PO 6.10: Poster

Dienstag, 2. März 1999, 14:00–16:00, Foyer

Decay of surface corrugation gartings in polymer films near the glass transition — •Marc Hamdorf and Diethelm Johannsmann — Max-Planck-Institut f"ur Polymerforschung, Ackermannweg 10, D-55128 Mainz

We report on surface-rheological experiments making use of the decay of imprinted surface corrugation gratings. The grating decay at temperatures higher than the glass transition temperature Tg is driven by surface tension. From the balance between surface tension and viscous stress the near-surface complex shear modulus G(w) can be derived. For polystyrene surfaces we find shear moduli slightly lower than the corresponding bulk values measured with a standard rheometer. The near-surface glass transition temperature is the same as the bulk calorimetric Tg.