Dresden 2006 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 11: POSTER Disperse Polymer Systems

CPP 11.33: Poster

Tuesday, March 28, 2006, 17:00–19:00, P3

Thermal Patterning of a Critical Polymer Blend — •Albert Voit, Alexei Krekhov, Wolfgang Enge, Lorenz Kramer, and Werner Köhler — Universität Bayreuth

The influence of inhomogeneous temperature fields on the demixing of a critical polymer blend has been investigated with the aim to control the spinodal demixing morphology. We have employed a focused laser beam to write spatial composition patterns into layers of the critical polymer blend poly(dimethylsiloxane)/poly(ethylmethyl siloxane) (PDMS/PEMS, Mw = 16.4/22.8 kg/mol) both in the one and in the two-phase region a few degrees above and below the critical temperature. Due to the critical divergence of the Soret coefficient, moderate temperature gradients are sufficient to induce composition modulations of large amplitude. In the two-phase regime the spinodal demixing pattern can be locally manipulated in a controlled way and the time evolution of various patterns can be studied. 2D-simulations based on a modified Cahn-Hilliard equation are able to reproduce the essential spatial and temporal features observed in the experiments.