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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 88: Responsive and Adaptive Systems

CPP 88.6: Vortrag

Donnerstag, 19. März 2020, 10:45–11:00, ZEU 114

Kinetics of phase separation in PNIPAM solutions after pressure jumps — Bart-Jan Niebuur¹, Leonardo Chiappisi^2,3, Xiaohan Zhang¹, Florian A. Jung¹, Alfons Schulte⁴, and •Christine M. Papadakis¹ — ¹TU München, Physik-Department, Fachgebiet Physik weicher Materie, 85748 Garching — ²Institut Laue-Langevin, Large Scale Structures Group, 38042 Grenoble, France — ³TU Berlin, Institut für Chemie, 10623 Berlin — ⁴University of Central Florida, Department of Physics and College of Optics and Photonics, Orlando, FL, U.S.A.

The thermoresponsive polymer PNIPAM in aqueous solution features lower critical solution behavior. Its cloud point depends on pressure with the coexistence line being an ellipse in the temperature-pressure frame. Performing fast pressure jumps from the one-phase to the two-phase region along with time-resolved small-angle neutron scattering, we can follow the pathway of phase separation with a time resolution of 50 ms and over a wide range of length scales [1]. Since the hydration state of PNIPAM depends on pressure, pressure jumps at low and at high pressures allow addressing the role of dehydration for the aggregate growth [2]. Varying the target pressure gives insight into the role of kinetic and thermodynamic factors.
1. B.-J. Niebuur et al., ACS Macro Lett. 7, 1155 (2018).
2. B.-J. Niebuur et al., Macromolecules 52, 6416 (2019).