Berlin 2015 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 49: P14: Polymer Dynamics

CPP 49.6: Poster

Wednesday, March 18, 2015, 10:00–13:00, Poster A

Comparison between thermal diffusion of a linear-chain polymer and a polymer microgel — •Bastian Pur¹, Werner Köhler¹, Klaus Huber², and Martin Schneider² — ¹Physikalisches Institut, Universität Bayreuth, 95440 Bayreuth, Germany — ²Physikalische Chemie, Universität Paderborn, 33098 Paderborn, Germany

In present theories for polymer thermophoresis in dilute solutions there are two theoretical models under discussion: draining coil and nondraining coil, corresponding to the Rouse and the Zimm picture, respectively. In order to discriminate between these models we have started a comparative investigation of a linear-chain polymer and a cross-linked microgel. The linear polymer sample used is poly(methyl-methacrylate) (PMMA) and the microgel sample is PMMA, cross-linked with ethylene-glycol-dimethacrylate (EGMA). In either case toluene is used as solvent. By means of transient holographic grating technique we obtained the thermal diffusion coefficient D_T, the Fickian diffusion coefficient D and the Soret coefficient S_T as functions of the polymer concentration c. We have found that for c → 0 the thermophoretic mobility of the linear polymer and the microgel are identical within experimental accuracy. The PMMA microgel shows, however, a significantly faster decay with increasing concentration, which we interprete as a result of the more rapidly increase of the microscopic friction.