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BP: Fachverband Biologische Physik

BP 15: Colloids and Complex Fluids I (Joint Session CPP/BP/DY)

BP 15.2: Vortrag

Dienstag, 21. März 2017, 11:45–12:00, ZEU 255

Corresponding States Law For Protein Solutions — •Florian Platten and Stefan U. Egelhaaf — Heinrich Heine University, Condensed Matter Physics Laboratory, Duesseldorf, Germany

The extended law of corresponding states, as proposed by Noro and Frenkel, involves a mapping of the phase behavior of systems with short-ranged attractions. We test its applicability to protein solutions with their complex interactions. We successfully map the experimentally determined metastable gas-liquid binodals to the binodals of short-ranged square-well fluids. This is achieved by representing the binodals as a function of the temperature scaled with the critical temperature (or as a function of the reduced second virial coefficient) and the concentration scaled by the cube of an effective particle diameter, where the scalings take into account the attractive and repulsive contributions to the interaction potential, respectively. The scaled binodals of the protein solutions coincide with simulation data of the adhesive hard-sphere fluid. Furthermore, once the repulsive contributions are taken into account by the effective particle diameter, the temperature dependence of the reduced second virial coefficients follows a master curve that corresponds to a linear temperature dependence of the depth of the square-well potential. We moreover demonstrate that, based on this approach and cloud-point measurements only, second virial coefficients can be estimated, which we show to agree with values determined by light scattering or by Derjaguin-Landau-Verwey-Overbeek (DLVO)-based calculations.

Platten et al., J. Chem. Phys. 142, 174905 (2015).