Colloidal Assembly at Curved Liquid-Liquid Interface

Colloidal particles can readily assemble into crystalline structure under confinement. When confined on a flat surface, spherical particles can pack efficiently with an arrangement of hexagons. However, the regular hexagonal packing configuration could be disrupted on a curved surface with resulting formation of defects. In this study, we investigated the self-assembled crystallography of fluorescence labeled polystyrene (PS) microspheres at lutidine-water interfaces, where liquid-liquid separation occurs as increasing the temperature to exceed the critical solution temperature of the mixture around 27-28 ^oC, We determined the assembled packing microstructure of PS microspheres at the liquid-liquid interface of varied curvature by direct confocal microscopic particle tracking. We observed disordered-to-crystalline structural transition in self-assembled PS colloidal monolayer at curved liquid-liquid interfaces when a critical curvature is exceeded.