Seminarium Fizyki Materii Skondensowanej

I will present our study on stability and thermodynamic properties of acolloidal suspension with a phase-separating solvent, such as abinary-liquid mixture with a miscibility gap. We focus on thenear-critical region of a solvent, where the critical fluctuations drivethe divergence of the correlation length. As a consequence, theadsorption properties of the colloids become important and the effectiveso-called critical Casimir forces (CCFs) acting between the colloidsemerge. The range and the strength of the CCFs are easily and reversibletunable by temperature and the bulk ordering field. Within an approach interms of effective one-component colloidal systems we analyze colloidalaggregation due to CCFsand thus allude to previous experimental studies which are still underdebate. Concerning the phase diagram, the phase segregation into twophases, one being rich and the other poor in colloidal particles, isinvestigated and the limitations of the effective approach, which iscommonly used, are discussed.