title: Critical casimir forces and colloidal phase transitions in a near-critical solvent: a simple model reveals a rich phase diagram.
abstract: From experimental studies, it is well known that colloidal particles suspended in a near-critical binary solvent exhibit interesting aggregation phenomena, often associated with colloidal phase transitions and assumed to be driven by long-ranged solvent-mediated (SM) interactions (critical Casimir forces), set by the (diverging) correlation length of the solvent. We present the first simulation and theoretical study of an explicit model of a ternary mixture that mimics this situation. Both the effective SM pair interactions and the full ternary phase diagram are determined for Brownian disks suspended in an explicit two-dimensional supercritical binary liquid mixture. Gas-liquid and fluid-solid transitions are observed in a region that extends well away from criticality of the solvent reservoir. We discuss to what extent an effective pair-potential description can account for the phase behavior we observe. Our study provides a fresh perspective on how proximity to the critical point of the solvent reservoir might influence colloidal self-assembly.
authors: Soft Condensed Matter, Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands.
authors: John R
authors: JR
authors: Edison
authors: Soft Condensed Matter, Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands.
authors: Nikos
authors: N
authors: Tasios
authors: Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, Netherlands.
authors: Simone
authors: S
authors: Belli
authors: H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom.
authors: Robert
authors: R
authors: Evans
authors: Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, Netherlands.
authors: René
authors: R
authors: van Roij
authors: Soft Condensed Matter, Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands.
authors: Marjolein
authors: M
authors: Dijkstra