Highly conductive and adhesive eutectogel for ultrasensitive strain/pressure sensing and self-powered material recognition

Flexible strain sensors have attracted much attention in human health monitoring. However, it is challenge to endow self-power and material recognition performance to conventional strain sensors. In this study, carboxylated polystyrene microspheres coated with polypyrrole (CPS@PPy) were synthesized by the in-situ growth of polypyrrole. The VAD-P-M eutectogel is prepared through one-step photoinitiated radical polymerization, which is composed of acrylic acid (AA) and 1-butyl-3-vinylimidazolium bromide (BVIM + Br − ) as polymeric networks, CPS@PPy microspheres and MXene nanosheets as conductive fillers into DES. Owing to the integration of multiple hydrogen bonds with a dual conductive network, the VAD-P-M gel architecture imparts exceptional comprehensive properties, including an elongation at break of up to 1283%, conductivity (0.064 cm∙ms −1 ) and adhesion strength to paper (881.3 kPa). Furthermore, the VAD-P-M gel sensor of strain gauge factor (GF S ) significantly increases from 2.38 to 5.10, while the pressure gauge factor (GF P ) spans from −0.0408 to −0.244 kPa −1 , enabling the sensor to accurately detect and monitor human motion, facial micro-expression and Morse code signals. More interestingly, a 3 × 3 pressure sensing array exhibited precise recognition of finger pressing positions (column and row). Importantly, we developed a single-electrode triboelectric nanogenerator (V-TENG) with an open-circuit voltage (V OC ) of 198.87 V and a short-circuit current (I SC ) of 1.67 μA, which can be used to self-powered human motion sensing and recognize different materials (glass, ceramics, plastic, human-skin, and aluminum). This outstanding performance of the VAD-P-M gel providing a new strategy for developing next-generation multifunctional eutectogels.