Highly robust and fatigue-resistant organic hydrogel composite elastomer fibers with multi-sensing capabilities

Converting hydrogels into one-dimensional (1D) fiber structures and integrating them into textiles offers a promising approach for the development of smart wearable devices. However, under repeated deformations, the fracture of low-energy amorphous crosslinking structure in the hydrogel leads to fatigue and hysteresis. This severely impairs the mechanical properties of hydrogel fibers and limits their potential applications. In this study, a novel strategy for fabricating composite hydrogel smart fibers featuring exceptional mechanical robustness and multisensory capabilities is proposed. By integrating an Ecoflex elastomer backbone into the organic hydrogel, the fatigue resistance is enhanced and hysteresis is eliminated, and no significant degradation of mechanical properties is observed after 10,000 cycles of 200% strain loading and unloading. The strain sensor based on this fiber has high sensitivity (gauge factor ∼3.0), fast response (140 ms)/recovery time (130 ms), and excellent repeatability (10,000 cycles at 70% strain). Moreover, the organic hydrogel/Ecoflex fiber (OHEF) exhibits remarkable resistance to dehydration and freezing. Smart textiles based on OHEF can detect diverse external stimuli, including deformation, temperature, proximity, pressure, and can perform passive sensing. The successful development of this fiber represents significant progress in applying hydrogels to wearable devices. Its multisensory properties highlight the great potential of OHEF for wearable electronics applications.