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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 4: Glasses and Glass Transition (joint session CPP/DY)
CPP 4.3: Vortrag
Montag, 16. März 2020, 10:15–10:30, ZEU 255
Dynamics of an arrested phase transition in a protein system — •Anita Girelli1, Hendrik Rahmann2, Nafisa Begam1, Anastasia Ragulskaya1, Fabian Westermeier3, Fajun Zhang1, Christian Gutt2, and Frank Schreiber1 — 1Universität Tübingen, Germany — 2Universität Siegen, Germany — 3DESY, Germany
The interest in phase transitions in biological systems has attracted much effort because of their numerous applications and its role as a mechanism underlying intracellular organization [1]. In this study the development of the spinodal decomposition near the gel/glass transition in a globular protein system was studied using X-Ray Photon Correlation Spectroscopy (XPCS) in the ultra small angle X-Ray scattering (USAXS) regime. The dynamics was probed at different quench depth, exhibiting two regimes: the first regime shows a single exponential decay of the correlation function, and the corresponding decorrelation time increases exponentially with waiting time tw. In the second regime, a second relaxation channel appears and the associated non-ergodicity parameter increases with tw until it becomes the dominating decay. The corresponding decorrelation time increases as a power law in tw. The dynamics was compared to simulations, which were performed by solving numerically the Cahn-Hilliard equation coupled with a gel transition. The effect of nanoscale arrested dynamics can be seen on the microscopic dynamics. Aging with quench depth dependence is visible and can be connected to real space parameters such as final concentration and mobility.
[1] Berry et al., Rep. Prog. Phys., 81, 046601, 2018