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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 21: Poster II
CPP 21.40: Poster
Tuesday, March 19, 2024, 18:00–20:00, Poster E
Microrheology under pressure using XPCS — •Fiona Berner1,2, Louisa Kraft1,2, Tobias Ecklund1,2, Klara Holl1,2, Nele Striker3, Fabian Westermeier3, Florian Schulz4, Felix Lehmkueler3, Werner Steffen1, and Katrin Amann-Winkel1,2 — 1Max Planck Institute for Polymer Research, Germany — 2Johannes Gutenberg University, Department of Physics, Germany — 3Deutsches Elektronen-Synchrotron (DESY), Germany — 4University Hamburg, Germany
Glycerol is a glass-forming liquid with a glass transition temperature around Tg ≈ 180 K at ambient pressure. The transition strongly depends on parameters such as the heating and cooling rate. We aimed to investigate the pressure dependence of the glass transition and viscosity in a mixture of 80 % glycerol in water, via a microrheological approach. Our group implemented a diamond anvil cell and a cryostat to the P10 Coherence Applications Beamline of Petra III at DESY.
Coherent X-rays from modern storage-ring-based radiation facilities provide unique capabilities to investigate both the structure and molecular-level dynamics of disordered soft matter systems. X-ray photon correlation spectroscopy (XPCS) can determine the dynamics on the timescale of µs to hundreds of s.
We calculated the intensity auto-correlation function g2 for small scattering vectors |q→ | and determined the relaxation rate for different pressures and temperatures. We observe that the applied pressure slows down the system, leading to a shift towards a higher glass transition temperature.
Keywords: Glass Transition; X-Ray Photon Correlation Spectroscopy; Dynamics in soft matter; Water-Glycerol; Diamond Anvil Cell