Criticality and phase separation in a two-dimensional binary colloidal   fluid induced by the solvent critical behavior
  We present an experimental and theoretical study of the phase behavior of a binary mixture of colloids with opposite adsorption preferences in a critical solvent. As a result of the attractive and repulsive critical Casimir forces, the critical fluctuations of the solvent lead to a further critical point in the colloidal system, i.e. to a critical colloidal-liquid--colloidal-liquid demixing phase transition which is controlled by the solvent temperature. Our experimental findings are in good agreement with calculations based on a simple approximation for the free energy of the system. 
O. Zvyagolskaya, A.J. Archer and C. Bechinger
cond-mat.soft cond-mat.stat-mech