Criticality and phase separation in a two-dimensional binary colloidal fluid induced by the solvent critical behavior
2. Physikalisches Institut, Universität Stuttgart - Pfaffenwaldring 57, 70569 Stuttgart, Germany, EU
2 Department of Mathematical Sciences, Loughborough University - Loughborough, LE11 3TU, UK, EU
3 Max-Planck-Institut für Intelligente Systeme - Heisenbergstr. 3, 70569 Stuttgart, Germany, EU
Accepted: 25 August 2011
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.
PACS: 82.70.Dd – Colloids / 68.35.Rh – Phase transitions and critical phenomena / 81.16.Dn – Self-assembly
© EPLA, 2011