Low-Hysteresis Hydrogels with Antidehydration as a Stretchable Strain Sensor for Gesture Recognition

Abstract

Achieving high mechanical strength, outstanding electrical performance, excellent toughness, antidehydration properties, and low hysteresis in stretchable electrically conductive hydrogels is crucial for enhancing their reliability in strain-sensing applications. However, obtaining hydrogels that simultaneously exhibit all of these desirable characteristics remains a significant challenge. Herein, a low-hysteresis hydrogel (LH hydrogel) was prepared by the strategy of nanointerpenetrating polymerization and the introduction of glycerol and LiCl. Due to the extensive presence of hydrogen bonds and the entanglement of monomer and polymer fragments, the LH gels exhibit excellent mechanical properties, including Young’s modulus of 0.12 MPa, fracture strength of 0.18 MPa, and tensile strain of 5.15 mm mm^–1, along with low hysteresis. Hence, strain sensors based on LH gels have excellent sensing performance, with a gauge factor of up to 2.6, while showing excellent resilience and fatigue resistance. The strain sensor can accurately monitor human movements in daily life, including strains in the wrist, knee, and finger joints. Notably, it demonstrates a 98.08% accuracy rate in gesture recognition. Our results suggest that the LH gels have great potential for use in a variety of sensing applications such as human motion monitoring, flexible electronics, and artificial skin.