8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Wed 711:10-14:00P5.113Structure, phase behavior and stability of colloidalsuspensions with critical solventsThomas Friedrich Mohry, 1 Ania Maciolek, 2 and Siegfried Dietrich 11 Max-Planck-Institute for Intelligent Systems and ITAP, University Stuttgart, Heisenbergstr.3, 70569, Stuttgart, Germany2 Max-Planck-Institute for Intelligent Systems and IPC, Polish Academy of Sciences,Stuttgart, GermanyFor colloids suspended in a near-critical binary solvent the so-called critical Casimir forces offerthe opportunity to tune reversibly the interactions between the colloids. The critical Casimir forcesare induced by critical fluctuations of the concentration of the binary solvent and act on the lengthscale set by the correlation length, which diverges upon approaching the critical point. We investigatethe effects of the critical Casimir forces on the structure, phase behavior and stability of thecolloidal suspension by using field-theoretical methods, the integral equation theory and within thedensity functional approach. Our quantitative results show that the critical Casimir forces can leadto phase separation in colloidal suspension and to aggregation phenomena. We relate our findingsto experiments.113