Phase transitions at interfaces: Flocculation of charge stabilised colloids in liquid mixtures

An intriguing phenomenon of reversible flocculation of charge-stabilised colloids in liquid mixtures is described. Some recent results concerning the shape of the flocculation surface, especially near special critical points (e.g. a double critical point, DCP), are also discussed. The findings regarding the kinetics of aggregation/fragmentation have been reviewed. The theoretical efforts behind the mechanism of this phenomenon (e.g. prewetting, capillary condensation, adsoprtion-driven secondary minimum in the interparticle DLVO potential, Casimir forces, etc.) are outlined. The role of special critical points (e.g. a DCP or a quadruple critical point, QCP) in elucidating several key features of the above phenomenon is underlined. Several challenging problems in this emerging area that demand attention, are pointed out