Environmentally stable, mechanically flexible, self-adhesive, and electrically conductive Ti3C2TX MXene hydrogels for wide-temperature strain sensing

Conductive hydrogels are promising in the flexible wearable electronic applications due to their unique feature of intrinsic stretchability, reversible flexibility, and high electrical conductivity . However, severely poor adaptability under cold or hot environmental conditions along with inferior adhesiveness to various substrates greatly hinders the potential applications in such emerging field. Herein, we describe a mechanically flexible and electrically conductive nanocomposite hydrogel composed of polyacrylamide-co-acrylic acid/chitosan covalent-network reinforced by Ti 3 C 2 T x MXene nanosheets within water-glycerol binary solvent via a simple one-pot free radical polymerization . Notably, incorporation of a low content (0.1–0.3 wt%) of MXene promotes the rapid gelation of the polymer molecules in only 10 min. The optimized hydrogel containing 0.2 wt% MXene not only possesses excellent mechanical performance (e.g., tensile elongation of ~1000%) and improved electrical conductivity (~1.34 S/m), but also shows stable temperature tolerance from − 20 to 80 °C and self-adhesion with various substrates (e.g., steel, glass, rubber, plastics and skin) as well as a rapid self-healable feature (~1.3 s). Further, such hybrid MXene hydrogel exhibits dual sensations under different strain (1–600%) and stress (80–3200 Pa) ranges, good applicability for various deformation conditions (tension/bend/compression), and wide temperature adoptability with stable repeatability. Clearly, this versatile MXene nanocomposite hydrogel developed may provide a new route for the rational design and development of advanced skin-like sensor for complex environmental application.