Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 27: Poster: Soft Matter Dynamics / Glasses

CPP 27.6: Poster

Dienstag, 8. März 2016, 18:15–21:00, Poster B2

Diffusion of PMMA: microgels and linear polymer — •Bastian Pur¹, Werner Köhler¹, Klaus Huber² und 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 cross-linked microgels. The linear polymer sample used is poly(methylmethacrylate) (PMMA) and the microgel samples are PMMA cross-linked with different amounts of ethylen-di-methacrylate (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 out that for c → 0 the thermophoretic mobility of the linear polymer and the microgel with 3.5% EGMA are identical within experimental accuracy. In addition we performed dynamic light scattering experiments to characterize the different microgel samples. Thereby we obtained that the diffusion coefficient is independent of the amount of cross-linker and so are (by using Stokes-Einstein equation) the hydrodynamic radii of the microgels.