CO2 Detection Using Potentiometric Sensors Based on PIM-1/DES Membranes

Polymers of Intrinsic Microporosity (PIMs) are a class of polymers characterized by a native microporous network resulting in a high surface area. PIMs also display a highly tunable and efficient gas permeability, attracting a lot of attention in several electrochemical applications. In this work. PIM-1 was combined with a deep eutectic solvent (DES) for the production of a potentiometric sensor for CO2. This study reports the synthesis of both components, the fabrication of composite membranes via solvent casting and impregnation, and their evaluation as CO2 responsive materials together with a comprehensive characterization. The PIM-1/DES materials demonstrated efficient CO2 capture and release behavior with open-circuit voltage responses recorded under controlled CO2 exposure and adsorption–desorption cycling with full recovery. The membrane exhibited a response of 29 s in pure CO2 with a recovery time of 240 s. The sensors followed a logarithmic correlation between CO2 concentration and voltage variation and it showed a sensitivity of up to 9.6 mV/%CO2. These findings indicate that the developed sensor offers high reproducibility, fast response, and reliable detection of variable CO2 levels, underscoring its strong potential for practical implementation in environmental and industrial monitoring applications