Regensburg 2022 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 33: Focus Session: Soft Matter and Nanocomposites: New Opportunities with Advanced Neutron Sources 1

CPP 33.5: Vortrag

Donnerstag, 8. September 2022, 10:45–11:00, H38

Kinetics of mesoglobule formation and dissolution in solutions of thermoresponsive polymers after fast pressure jumps — Bart-Jan Niebuur¹, Leonardo Chiappisi², Alfons Schulte³, and •Christine M. Papadakis¹ — ¹Technical University of Munich, Physics Department, Garching, Germany — ²Institut Laue-Langevin, Grenoble, France — ³University of Central Florida, Department of Physics and College of Optics and Photonics, Orlando FL, U.S.A.

The thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAM) features lower critical solution temperature behavior in aqueous solution with the cloud point depending on pressure [1]. Fast pressure jumps across the coexistence line in combination with time-resolved small-angle neutron scattering elucidate the pathways of mesoglobule formation and disintegration over a wide range of length scales with a time resolution of 50 milliseconds. Varying the start and target pressures gives insight into the role of thermodynamic and kinetic factors governing mesoglobule formation [2,3]. For disintegration, the osmotic pressure of the solvent within the mesoglobules is the decisive factor for the mechanism and the time scales [4]. These results are of importance for applications of thermoresponsive polymers as switches. 1. B.-J. Niebuur et al., ACS Macro Lett. 6, 1180 (2017). 2. B.-J. Niebuur et al., ACS Macro Lett. 7, 1155 (2018). 3. B.-J. Niebuur et al., Macromolecules 52, 6416 (2019). 4. B.-J. Niebuur et al., RSC Nanoscale 13, 13421 (2021).