PHOTOINDUCED IONIC-CONDUCTIVITY SWITCHING IN POLYMER COMPOSITE FILM WITH AZOBENZENE DERIVATIVE

The polymer composite film consisting of poly(vinyl chloride) (PVC), an azobenzene liquid crystal, lithium perchlorate, and a crown ether has been designed which undergoes photo-induced switching of ionic conductivity by photochromic phase transition. UV light irradiation on the composite film causes isomerization of the azobenzene derivative from the trans to cis isomers accompanied by its phase transition from the crystal to isotropic states, which thus leads to drastic ionic-conductivity increase of the film by more than two orders of magnitude. The enhanced ionic conductivity can be restored to the initial state by visible light irradiation. The photo-induced ionic conductivity switching was found to be quite reversible. © 1990.