Activity-based molecular CO2 detection by amine-free polymers in organic and aqueous media

Abstract

Many machineries have been developed to detect and monitor the ubiquitous molecule “CO2” in a global warming essay. CO2 detection in water with amine-free functionalities and N-heterocyclic carbene (NHC)-based systems remains of interest in the sensing community. This manuscript introduces a unique fluorescent polymeric system capable of CO2 detection in organic and water media. The imidazolium-based ionic polymer controls fluorescence using an ON/OFF mechanism. The formation of the complex NHC-CO2- turns “ON” fluorescence in organic media and solid films through the photo-induced transmission “OFF” photophysical phenomenon. In contrast, fluorescence quenching was observed in the water medium due to aggregation-caused quenching (ACQ) of polymeric nanoparticles upon CO2 gas introduction, which resulted in the formation of carbamate anions in water. The single ionic polymer P1 works in a multimode pathway and detects CO2 gas in various phases such as organic solvents, water, and solid films, through fluorometric analysis.