Rational Design for Efficiently Improving the Sensitivity of Ti₃C₂ MXene-Based Waterborne Polyurethane Composites toward High-Performance Wearable Electronics

Surface structure modulation provides a feasible strategy for designing highly sensitive electronics. Herein, a “casting–permeating–curing” method is proposed to fabricate high-performance composites using Ti3C2 MXene, modified carbon black (MCB), and waterborne polyurethane (WPU). The Ti3C2@MCB/WPU composite not only presents large stretchability (>400%) and robust strength (∼20.6 MPa) but also possesses superior conductivity, which results from the excellent interfacial interaction between Ti3C2@MCB and WPU. Most importantly, the interconnected conductive network with adjustable junctions constructed by hybrid conductive nanomaterials endows the composite with high sensitivity (gauge factor = 78.75). Therefore, the Ti3C2@MCB/WPU composite-based strain sensor features a wide sensing range (0–120°), low detection limit (∼0.1°), a short response time (∼142 ms), and excellent stability (∼1000 cycle fatigue tests). Benefiting from the above features, human motions, including pulse, phonation, and joint movement, are successfully and accurately detected by utilizing composite-based strain sensing. The findings demonstrate that the composite with versatilities exhibits wide potential in the fields of wearable electronics, smart robots, and human–machine interfaces.