Ionic Conductive, Antidrying, and Flexible Organohydrogels\nSuitable for Pressure Sensors and Gas Sensors

Abstract

In\nrecent years, hydrogels have become excellent optional materials\nfor flexible sensors due to their high stretchability and biocompatibility.\nHowever, the instabilities of hydrogels including the tendency to\ndry out and the poor reusability seriously limit their applications.\nHerein, a double-network (DN) organohydrogel is derived by regulating\nthe mechanical property, conductivity, and antidrying characteristic\nof the poly (acrylamide-co-acrylic acid) (P­(AM-<i>co</i>-AA)) hydrogel. Specifically, the ionic coordination (CO₂LFe^III) is imported as the secondary cross-link to strengthen\nthe mechanical property, and LiCl in ethylene glycol (EG) solution\nenhances the conductivity and antidrying characteristics simultaneously.\nBenefiting from these improvements of material characteristics, the\niontronic pressure sensor assembled from the DN organohydrogel demonstrates\nexcellent performances such as a high sensitivity, fast response/recovery\ncharacteristic at different frequencies, and remarkable fatigue resistance.\nThese properties also enable physiological signal detections in diverse\nscenarios. At the same time, with the help of abundant functional\ngroups in the double network and solvent, the organohydrogel exhibits\npractical NH₃ sensing performances including high response,\nstrong gas selectivity, and excellent long-term stability, paving\nthe way toward broader multiscene applications of hydrogels.