Color Change of<i>N</i>-Isopropylacrylamide Copolymer Bearing Reichardts Dye as Optical Sensor for Lower Critical Solution Temperature and for Host−Guest Interaction with β-Cyclodextrin

Abstract

With a simple reaction pathway, a polymerizable solvatochromic dye monomer was synthesized. Copolymerization of this dye monomer with NiPAAM leads to formation of a solvatochromic copolymer with lower critical solution temperature (LCST) behavior. This resulting copolymer visualizes via a red-orange color change (a) the LCST phase transition and (b) the host−guest interaction of cyclodextrin with this copolymer simply by the naked eye. Actually, these effects are completely reversible.