Reactive Fluorescence Turn-On Probes for Fluoride Ions in Purely Aqueous Media Fabricated from Functionalized Responsive Block Copolymers

Abstract

We report on the fabrication of a novel type of responsive double hydrophilic block copolymer (DHBC)-based highly selective and sensitive fluorescence “turn-on” reactive probes for fluoride ions (F–) working in purely aqueous media by exploiting F–-induced cyclization reaction of nonfluorescent moieties to induce the formation of fluorescent coumarin moieties, as inspired by the previous work of the Swager research group (Angew. Chem. Int. Ed. 2003, 42, 4803). Diblock copolymers bearing F–-reactive moieties (SiCouMA) in the thermoresponsive block, PEO-b-P(MEO2MA-co-OEGMA-co-SiCouMA), were synthesized at first via reversible addition–fragmentation chain transfer (RAFT) technique followed by postmodification, where PEO, MEO2MA, and OEGMA are poly(ethylene glycol), di(ethylene glycol) monomethyl ether methacrylate, and oligo(ethylene glycol) monomethyl ether methacrylate, respectively. As-synthesized diblock copolymers molecularly dissolve in water at room temperature and self-assemble into micellar nanopart...