PAA/PVA/PEDOT:PSS/Ti ₃ C ₂ T _X Hydrogel Strain Sensor with Enhanced Performance for Information Encryption and Wireless Motion Monitoring

As biocompatible soft materials with stimuli-responsive characteristics, wearable strain sensors based on conductive hydrogels hold substantial promise across diverse engineering fields. However, their practical applications are often hindered by limited sensitivity and issues related to single functionality. This study presents a multifunctional composite hydrogel composed of PAA/PVA/PEDOT:PSS/Ti 3 C 2 T X designed for flexible strain sensors and synthesized through a straightforward one-pot polymerization technique. The incorporation of Ti 3 C 2 T X MXene nanosheets significantly enhances the porous architecture and mechanical properties of the hydrogel. This hydrogel features a combination of covalent and physical cross-linking networks, showcasing remarkable elastic recovery, puncture resistance, stretchability, robust interfacial adhesion, and self-healing capabilities. The hydrogel-based strain sensor demonstrates exceptional performance, including high sensitivity (GF = 21.36 in the 31–50% strain range), a low detection limit (53.0 Pa), rapid response and recovery times (42 ms/38 ms), and long-term stability (>1,600 cycles). Its practical applications in information encryption, handwriting recognition, and wireless robotic motion monitoring highlight its potential as a versatile platform for advanced flexible sensing technologies.