Hydrogel-Based Sensitive and Humidity-Resistant Oxygen Gas Sensors Enabled by Porous Ecoflex Membranes

In this paper, humidity-resistant, stable and sensitive oxygen gas sensors were fabricated by covering porous membranes on the surface of carrageenan/polyacrylamide (PAM) double-network (DN) hydrogel. The breathable and waterproof porous ecoflex membranes were fabricated via a facile and cost-effective template method. The proposed approach is capable of creating the micropores on the ecoflex membranes using the salt as hard template and water as the solvent. We also proposed the working mechanism of the ion-conducting hydrogel based oxygen sensor. The porous membranes enhance the immunity of the hydrogel sensor to humidity and retain its high response to oxygen. The response of the sensor to oxygen can keep stable in different relative humidity (RH) with the sensitivity of $4.49\times 10^{-2}\text{ppm}^{-1}$.