(543f) Transient Reorientation of Liquid Crystals Induced By Water Transport

Liquid crystals (LCs) present an ordered environment at interfaces that enables new functionalities in light focusing devices and biosensors. Numerous applications of LCs rely on instantaneous reorientation of the molecules at an interface which can propagate well into the bulk. In this contribution, we show that the spontaneous flux of water across the interface between a thermotropic liquid crystal and an aqueous phase gives rise to a transient reorientation of the liquid crystal; a new principle that differs from that of explicit liquid crystal-solute interactions. A critical water flux is created by changing the water activity of an aqueous electrolyte solution using specific salts; water is then transported through the liquid crystal phase and across the interface. The orientational response of the liquid crystal phase is then imaged by polarized optical microscopy. The magnitude of the spontaneous water flux is controlled by the concentration and type of solutes, as well as the rate of salt addition. These results provide unprecedented fundamental principles that can be exploited to design biological sensors, drug delivery systems, and molecular machines.