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Two-Particle Microrheology of quasi-2D Viscous Systems

V. Prasad·S. A. Koehler·Eric R. Weeks
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Abstract

We study the correlated motions of colloidal particles in a quasi-2D system (Human Serum Albumin (HSA) protein molecules at an air-water interface) for different surface viscosities $η_{s}$. We observe a transition in the behavior of the correlated motion, from 2-D interface dominated at high $η_{s}$ to bulk fluid-dependent at low $η_{s}$. The correlated motions can be scaled onto a master curve which captures the features of this transition. This master curve also characterizes the spatial dependence of the flow field of a viscous interface in response to a force. From the flow field and the correlated particle motions, we calculate a two-particle MSD (mean square displacement) for direct comparison with rheological measurements.

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V. Prasad, S. A. Koehler, Eric R. Weeks. 2006-10-17. Two-Particle Microrheology of quasi-2D Viscous Systems. https://doi.org/10.1103/physrevlett.97.176001

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