Dresden 2026 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 46: Poster II
CPP 46.37: Poster
Donnerstag, 12. März 2026, 09:30–11:30, P5
Quasi-elastic neutron scattering of perdeuterated poly(N-isopropylacrylamide) and hydration changes across the demixing transition — •Alfons Schulte1, Eric Rende1, Marcell Wolf2, Thomas Müller3, Dirk Schanzenbach4, Andre Laschewsky4,5, and Christine M. Papadakis6 — 1Department of Physics and College of Optics and Photonics, University of Central Florida, Orlando, U.S.A. — 2Heinz Maier-Leibnitz Zentrum (MLZ), TUM, Garching, Germany — 3FZ Jülich, JCNS at MLZ, Garching, Germany — 4Institut für Chemie, Universität Potsdam, Potsdam-Golm, Germany — 5Fraunhofer-Institut für Angewandte Polymerforschung, Potsdam-Golm, Germany — 6TUM School of Natural Sciences, Soft Matter Physics Group, Garching, Germany
We investigate the hydration dynamics of perdeuterated poly(N- isopropylacrylamide) (PNIPAM-d10) to elucidate the molecular mechanism of its demixing transition. Quasi-elastic neutron scattering (QENS) and Raman spectroscopy were measured in a 25 wt% PNIPAM-d10 aqueous solution over the temperature range from 298 to 325 K. There is a significant upward shift in the cloud point by about 4 degrees. Deuteration suppresses incoherent scattering from the polymer, allowing a clear view of hydration water dynamics. The dynamic susceptibilities reveal the relaxation processes for bulk and bound water, with the bound fraction decreasing sharply near the transition. The relaxation times of hydration water are consistently lower than in the protiated polymer, indicating faster local dynamics. Raman spectra show abrupt C-D band frequency shifts at the transition, reflecting side-group dehydration.
Keywords: PNIPAM; Thermoresponsive polymers; Hydration; Perdeuteration; Neutron scattering