Ionochromic 4,4′-azobispyridinium salt-incorporated polymer: synthesis and optical properties

Abstract Azobispyridinium-bearing polyelectrolyte linked with flexible alkyl chain was synthesized and characterized. The polymer showed absorption changes upon addition of hydroxide anion with an isobestic point in UV–visible spectrum. It is presumed that conformational change of the azo group in the main chain is responsible for the point. Transduction of physical information (hydroxide concentration) into an optical signal from azo group was related to the ionochromic effect. Electrostatic self-assembled multilayer of the polymer with appropriate polyanion was carried out via layer-by-layer deposition.