Highly sensitive and skin-conformable PVA/SBMA/LiCl hydrogel iontronic pressure sensor for intelligent rehabilitation training system

A highly flexible double-network ion-conductive hydrogel pressure sensor was developed. • The sensor achieves a 0.5 Pa detection limit, 343.428 kPa⁻¹ sensitivity, and a 50 ms response time. • An intelligent system tracks finger, knee, and mouth-opening movements in real time during rehabilitation. With the rapid development of wearable healthcare and intelligent rehabilitation technologies, flexible pressure sensors with excellent skin conformability and high sensitivity are highly desired for precise physiological monitoring. Here, we report an ion-conductive hydrogel pressure sensor based on a double-network architecture. Through rational compositional design and surface microstructuring, the hydrogel exhibits mechanical softness comparable to human skin while simultaneously enhancing the interfacial electric double-layer effect, leading to significantly improved pressure sensitivity. The sensor achieves a high sensitivity of 343.4 kPa⁻¹ within the low-pressure regime of 0–40 kPa, an ultralow detection limit of 0.5 Pa, and fast response/recovery times of 50 ms. Moreover, the device maintains excellent stability over 16,000 loading–unloading cycles. By integrating a signal acquisition circuit and a real-time monitoring platform, the sensor enables quantitative tracking of human motions, including finger bending, knee joint movement, and restricted mouth opening. This work provides a promising strategy for the development of high-performance electronic skin and wearable rehabilitation monitoring systems. Download: Download high-res image (135KB) Download: Download full-size image