Aggregation-induced emission of tetraphenylethylene-modified polyethyleneimine for highly selective CO2 detection

A polymer-based visible and quantitative fluorometric assay for CO 2 gas is constructed using branched polyethyleneimine (PEI) covalently modified with tetraphenylethylene (TPE). The sensing mechanism relies on the reaction of CO 2 with alkylamines of PEI to induce the “solution-to-precipitation” phase transition of the sensory polymer (TPE–PEI), thus resulting in strong aggregation-induced fluorescent emission of TPE–PEI. It works in a relatively environmental benign ethanol medium and avoids the use of toxic amine compounds with unpleasant odor. More importantly, this system is proved to be highly tolerant to possibly coexisting water, carbon monoxide , acid SO 2 and H 2 S gases as well as many common volatile organic compounds. These characteristics make the presently developed fluorescent chemosensor hold great potential for many real-world applications.