Synthesis of Vinyl Polymers Incorporating Different Crowned Azobenzene Moieties and Their Application to Photoresponsive Ion-Conducting System

Abstract

Abstract Vinyl polymers carrying a crowned azobenzene side chain, which have a crown ether moiety and an azobenzene moiety in two different ways, were synthesized and their ion-conducting behavior investigated. The crowned azobenzene vinyl polymer carrying a crown ether moiety apart from its azobenzene moiety, 1, exhibited distinct liquid crystal phases, which were stabilized by the addition of alkali metal perchlorates. Ion-conducting composite films containing crowned azobenzene vinyl polymer 1 underwent remarkable photoinduced ionic-conductivity switching. The system of vinyl polymer 2, which carries a crown-ether ring in the vicinity of its azobenzene moiety, is greater in the magnitude of photoinduced ionic-conductivity change (ionic-conductivity ratio) than the system of vinyl polymer 1. X-Ray diffraction measurements suggested that the difference in the ionic-conductivity switching between the two crowned azobenzene polymers is derived from the difference in the order–disorder arrangement of the crown ether moiety on the photoisomerization of the azobenzene moiety from its trans form to the corresponding cis one.