A sandwich-structured liquid metal-based sensor with thermoplastic polyurethane and polyaniline nanocomposite for high sensitivity and durability

The development of high-performance flexible strain sensors is hampered by the difficulty in simultaneously achieving high sensitivity, broad stretchability, and long-term stability. In this study, an electrospinning liquid metal (LM)-based membrane was developed for the high-sensitivity detection of biomechanical signals and physiological parameters. Thermoplastic polyurethane (TPU), selected for its excellent biocompatibility and flexibility, was chosen for the application. LM nanoparticles were ultrasonically dispersed into TPU via electrospinning to obtain the highly elastic, stretchable nanofiber membrane. Polyaniline (PANI) and gallium–indium alloy (EGaIn) droplets were then combined with the electrospun membrane via in situ polymerization and coating methods, forming a multi-scale three-dimensional (3D) conductive network structure. The developed composite demonstrated exceptional operational resilience, maintaining consistent performance over 10,000 mechanical cycles while achieving a maximum detectable strain of 300%. The developed flexible strain sensor achieved a high gauge factor of 206, demonstrating its significant potential for applications in health monitoring and human–machine interaction. Graphical abstract The alternative text for this image may have been generated using AI.