Fabrication of PNIPAM ionogels with enhanced conductive and mechanical properties for wearable biosensor

Poly(N-isopropyl acrylamide) (PNIPAM) hydrogel, renowned for its rapid response to temperature changes, has emerged as a promising material for soft electronic and wearable biosensors. However, its practical use in wearable biosensors is hindered by challenges such as poor mechanical strength, limited conductivity, and potential biosafety concerns due to residual polymerization initiators. To overcome these limitations, an edible initiator of Vitamin C is introduced to catalyze the polymerization of NIPAM. This process is further enhanced by the addition of the biocompatible ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIm][Cl]), which accelerates polymerization and improves the hydrogel’s conductivity and mechanical properties. Experimental results demonstrate that the obtained ionic hydrogel holds significant potential for wearable biosensor applications, particularly for monitoring human physiological signals.