Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: SYMPOSIUM Driven Soft Matter II

CPP 17.6: Talk

Tuesday, February 26, 2008, 15:45–16:00, C 130

Flow NMR of polymers in external fields — Ute Böhme, Frank Bagusat, and •Ulrich Scheler — Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, D-01069 Dresden

Pulsed-field gradient NMR is applied to study the motion of polymers in an external electric field and under mechanical shear. The application of an electric field drives motion of charged species. In conjunction with the diffusion coefficient from th electrophoreitc mobility the effective charge per molecule is derived [1-3]. The electric field applicable in the aqueous system is too weak to deform the polymer or even abstract counterions.

In a shear flow established in a Couette cell partial orientation of polymer chains is measured via residual dipolar couplings. The entire flow field in a non-symmetric flow cell is monitored by a combination of PFG NMR and NMR imaging exhibiting regions of high shear and locally low shear, where polymers relax [4].

[1] U. Böhme, U. Scheler, Colloids and Surfaces A, 222, (2003), 35 [2] U. Böhme, C. Vogel, J. Meier-Haack, Us. Scheler, J. Phys. Chem. B 111, (2007), 8344 [3] U. Böhme, U. Scheler, Journal of Colloid and interface science 309, (2007), 231 [4] A. Gottwald, U. Scheler, Polymer Preprints, 44, (2003), 273