Dresden 2020 – scientific programme
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BP: Fachverband Biologische Physik
BP 8: Poster I
BP 8.5: Poster
Monday, March 16, 2020, 17:30–19:30, P2/1OG
Unusual correlated dynamics in aqueous protein solutions due to thermal expansion induced shear flow — •Nafisa Begam1, Anastasia Ragulskaya1, Anita Girelli1, Hendrik Rahmann2, Fabian Westermeier3, Christian Gutt2, Fajun Zhang1, and Frank Schreiber1 — 1Universität Tübingen, Germany — 2Universität Siegen, Germany — 3DESY, Germany
We study the dynamics of aqueous solutions of the globular protein bovine γ-globulin in the presence of polyethylene glycol, filled into quartz capillaries, during liquid-liquid phase separation using X-ray photon correlation spectroscopy (XPCS). Simultaneously, we probe the kinetics of the phase separation by USAXS. Microscopy measurements revealed that the solutions undergo a thermal expansion or contraction during the temperature change which induces a shear flow in the solution. To study the influence of such an intrinsic shear flow on the phase transition, we performed the measurements in the middle of the capillary, having a large shear flow, and rear of the capillary, having a negligible shear flow. Interestingly, the kinetics observed in these two cases are similar. However, in the middle of the capillary, the dynamics exhibits a strong heterogeneity, and in the rear of the capillary, the degree of heterogeneity is significantly smaller. Our findings could have a large impact in the field of condensed matter where XPCS is an important tool in studying bulk dynamics and the intrinsic shear flow is comparable to the time scale of the system dynamics.
[1] Busch et al., Eur. Phys. J. E, 26, 55, (2008)
[2] Urbani et al., J. Sync. Rad., 23, 1401, (2016)