PEG-engineered semi-interpenetrating network hydrogel with superior deformability and robustness for ultra-sensitive pressure sensing.

Conductive hydrogels have garnered substantial attention in wearable flexible electronics owing to their exceptional mechanical flexibility and comfort, yet the development of durable hydrogels with high sensitivity under low pressure remains a critical challenge. Here, we propose a facile one-pot in-situ polymerization strategy for the creation of a semi-interpenetrating network hydrogel pressure sensor, integrating polyethylene glycol (PEG) embedded in a crosslinked polyacrylamide (PAM) matrix, with MXene serving as the conductive filler. The resulting semi-interpenetrating network, formed by PEG through its flexible chains and hydrogen bonding interactions with both PAM and MXene, endows the hydrogel with excellent deformation resistance and superior mechanical properties, without compromising its electrical conductivity. Notably, the hydrogel demonstrates a remarkable peak tensile strength of 762 kPa at a strain of up to 1226 %, with full recovery after 70 % compression, and the assembled hydrogel sensor achieves a sensitivity of 6.69 kPa-1 within a rather small pressure range from 0 to 10 kPa. Owing to its ultra-sensitivity, biocompatibility and flexible wearability, the assembled sensor reveals significant medical application potentials, such as aiding deaf- mutes through handwriting recognition and throat vibration-speech translation, detecting unconsciously subtle eye or limb movement for accurate epilepsy diagnosis, as well as expediting the wound healing by further optimizing its composition.