An Hg2+-selective chemosensor based on the self-assembly of a novel amphiphilic block copolymer bearing rhodamine 6G derivative moieties in purely aqueous media

Abstract

We report on the fabrication of an amphiphilic block copolymer-based colorimetric and fluorescent chemosensor for Hg²⁺ ions that was prepared by sequential RAFT polymerization of N-isopropylacrylamide (NIPAM) and a novel rhodamine-based Hg²⁺-recognizing monomer, R6GDM. Because of its amphiphilic properties, the block copolymer P[NIPAM]-b-P[R6GDM] can self-assemble into micelles, which allows it to be used as a chemosensor in aqueous solution. Upon addition of Hg²⁺ ions to the micelle solution, visual color change and fluorescence enhancement were observed. Moreover, it exhibits high sensitivity and selectivity for Hg²⁺ ions, relatively. Besides, it can serve as a potential multifunctional sensor to pH and temperature (in a specific temperature range: 25–40 °C or 40–52 °C). The water dispersibility and biocompatibility of these polymer micelles could provide a new strategy for detecting analytes in environmental and biological systems.