A highly sensitive and stretchable flexible strain sensor based on a PVC/PVA dual-substrate composite for wearable electronics

Flexible strain sensors have garnered significant attention for applications in wearable electronics and human–machine interfaces. However, many previously reported sensors suffer from limited deformability, complex fabrication, and unstable signal output under dynamic conditions, largely due to the low polarity, poor flexibility, and weak interfacial compatibility of commonly used polymer substrates. In this work, we report a PVC/PVA/MCNTs composite, in which the incorporation of PVA significantly improves the matrix polarity and interfacial interaction, thereby enhancing flexibility and processability. Fabricated via a simple solvent-casting method, the sensor exhibits high stretchability (>300 %), low hysteresis (2.04 %), fast response (240 ms), and stable performance over 1000 dynamic cycles. The sensor enables accurate, real-time monitoring of human joint movements and tracks varying bending angles of robotic fingers, confirming its practical value in biomechanical sensing and soft robotics control. These results demonstrate that the developed composite substrate exhibits excellent mechanical and sensing performance. The introduction of dual substrate components enhances matrix polarity, thereby broadening the range of compatible functional fillers and establishing a promising platform for future flexible electronic applications.