Rational Design of Nanostructured Ionic Conductive Polymer Organogels for Ultrasensitive Flexible Styrene Sensor

Flexible wearable sensors have been developed for real-time noninvasive detection in various emerging fields, such as electronic skin, human-machine interfaces, and micro/nanorobots, which are expected to provide new impetus for intelligent clinical diagnosis, smart city monitoring, and industrial safety production. Herein, ultrasensitive flexible sensors based on a series of ionic polymer organogels were developed via a facile one-step photopolymerization strategy, and the component of ionic gels was readily tuned by varying the organic anions and cations. Particularly, the sensor based on 1-butyl-1-methylpiperidine bis(trifluoromethanesulfonyl)imide ([BMPip][TFSI]) exhibited good sensing performance toward styrene vapor, featuring fast response, a low theoretical detection limit (ca. 193 ppb), and excellent long-term stability. In addition, it can be integrated with a Bluetooth module for real-time and rapid detection of styrene vapor via a smartphone application, implying its great potential for portable microdevice applications. Density functional theory (DFT) calculations confirmed that [BMPip][TFSI] exhibits high adsorption energy toward styrene and chlorobenzene, elucidating the gas sensing mechanism based on the ionic conduction and surface adsorption. Leveraging their highly transparent and flexible features, multifunctional ionic gels show great application potential in device integration and wearable sensing for styrene and chlorobenzene monitoring.