Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 40: Colloids and Complex Fluids II (Joint Session CPP/BP/DY)
BP 40.2: Vortrag
Mittwoch, 22. März 2017, 10:45–11:00, ZEU 260
A temporarily arrested state in protein solutions — •Stefano Da Vela1, Fajun Zhang1, Christian Exner1, Johannes Möller2, Zhendong Fu3, and Frank Schreiber1 — 1Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen — 2ESRF, Grenoble, France — 3JCNS, Garching, Germany
The interplay of liquid-liquid phase separation (LLPS) with the glass transition is a possible route to the formation of arrested states in colloidal and protein systems. LLPS requires attractive interactions, the microscopic details of which set the temperature dependence of the LLPS phase boundary. We report the kinetics of phase separation and arrest for two protein systems: γ-globulin in the presence of PEG 1000, featuring upper critical solution temperature behavior, and bovine serum albumin in the presence of Y(III), featuring lower critical solution temperature behavior. For both systems, the time evolution of the characteristic length is followed during phase separation by Ultra Small Angle X-ray Scattering (USAXS) and Very Small Angle Neutron Scattering(VSANS). This time evolution corresponds to classical LLPS proceeding by spinodal decomposition for shallow quenches in the two-phase region, and to arrested LLPS for deep enough quenches [1]. For intermediate quenches, we report evidence of an unusual three-stage coarsening process. In this case, a temporary arrest of the kinetics is found, which is overcome at later times. We interpret the finding in the light of simulations and experimental results on colloidal systems.
[1] Da Vela et al. Soft Matter, 2016, 12, 9334 - 9341