Photo-controlled Active Transport of Cations through Polymer/Liquid Crystal/Photoresponsive Crown Ether Ternary Composite Thin Films

A ternary composite thin membrane composed of poly(vinyl chloride) (PVC), liquid crystal (EBBA, CPB) and photoresponsive crown ether was prepared by the water-cast method. The aggregation states of the composite thin membrane and also the active transport of K⁺ ion, which is driven by photoirradiation and pH gradient through the ternary composite thin film, were investigated. The aggregation states of the composite thin film were investigated by transmission electron microscopic (TEM) observation and DSC studies. These revealed that EBBA existed as a continuous phase interpenetrating with the spongy three-dimensional network of PVC and that photoresponsive crown ether molecules were dispersed moleculary in liquid crystal domains. This shows that liquid crystal domains are able to play a role as a transporting phase for carriers and penetrants. The active transport of K⁺ ion took place through the ternary composite thin film both during photoirradiation and in the dark. The active transport of K⁺ ion through the thin film was accelerated by photoirradiation.