Synthesis of a new rhodamine‐containing block copolymer for highly selective and sensitive detection of Cu2+ and CN− ions in aqueous media

Abstract

AbstractDevelopment of new chemosensors that are selective and sensitive to Cu2+ and CN− ions, especially in aqueous media, is of tremendous importance. We report the synthesis of a new block copolymer that is capable of highly selective and sensitive detection of Cu2+ and CN− ions in aqueous media. Poly(t‐butylacrylate)‐block‐poly(3‐bromopropylacrylate) was prepared using the reversible addition–fragmentation chain transfer polymerization technique. This block copolymer was reacted with 2,4‐dihydroxybenzaldehyde followed by reaction with rhodamine B hydrazide for successful incorporation of the desired rhodamine units into the block copolymer structure. Cu2+‐induced opening of the spirolactam ring of the rhodamine units resulted in rapid and easily noticeable colour change, thus enabling a highly selective detection of Cu2+ ions in aqueous media for concentrations as low as 2 µmol L−1. We further demonstrate that this Cu2+ bound polymer complex can further act as a selective and sensitive sensing platform for CN− in aqueous media with concentrations <1 µmol L−1 (0.06 ppm). Moreover, the polymer can also be used to remove Cu2+ from aqueous media. © 2014 Society of Chemical Industry