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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 53: Responsive and Adaptive Systems II

CPP 53.2: Vortrag

Freitag, 22. März 2024, 12:00–12:15, H 0107

Dynamic Behavior of Poly(N-isopropylmethacrylamide) in Water/Methanol Mixtures — Chia-Hsin Ko¹, Patrick Wastian¹, Dirk Schanzenbach², André Laschewsky^2,3, Peter Müller-Buschbaum¹, and •Christine M. Papadakis¹ — ¹TUM School of Natural Sciences, Technical University of Munich, Garching, Germany — ²Universität Potsdam, Institut für Chemie, Potsdam-Golm, Germany — ³Fraunhofer-Institut für Angewandte Polymerforschung, Potsdam-Golm

The thermoresponsive polymer poly(N-isopropylmethacrylamide) (PNIPMAM) features peculiar structural behavior [1]. Here, we investigate the dynamics of PNIPMAM in aqueous solution and in water/methanol mixtures in the one-phase region. Using dynamic light scattering, we observe two diffusive dynamic modes in a wide range of temperatures and polymer concentrations, which reflect local and large-scale dynamics. The scaling behavior of the dynamic correlation length of the fast mode deviates strongly from mean-field predictions, which may be related to the presence of the large-scale inhomogeneities, assigned to the enhanced hydrophobic effect. In water/methanol mixtures, the slow mode is strongly reduced, and the scaling exponent features non-monotonous behavior. Thus, the hydrophobic interactions result in complex behavior.
1. C.-H. Ko, C. M. Papadakis et al., Macromolecules 2020, 53, 6816.

Keywords: polymer solutions; thermoresponsive polymers; co-nonsolvency; dynamic light scattering