Robust Conductive Hydrogels with Ultrafast Self-Recovery and Nearly Zero Response Hysteresis for Epidermal Sensors

Xiuru Xu; Chubin He; Feng Luo; Hao Wang; Zhengchun Peng

doi:10.3390/nano11071854

Robust Conductive Hydrogels with Ultrafast Self-Recovery and Nearly Zero Response Hysteresis for Epidermal Sensors

Nanomaterials (Basel). 2021 Jul 19;11(7):1854. doi: 10.3390/nano11071854.

Authors

Xiuru Xu^{1

2}, Chubin He², Feng Luo¹, Hao Wang¹, Zhengchun Peng²

Affiliations

¹ Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronic Engineering, College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen 518060, China.
² Center for Stretchable Electronics and Nano Sensors, School of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.

Abstract

Robust conductive hydrogels are in great demand for the practical applications of smart soft robots, epidermal electronics, and human-machine interactions. We successfully prepared nanoparticles enhanced polyacrylamide/hydroxypropyl guar gum/acryloyl-grafted chitosan quaternary ammonium salt/calcium ions/SiO₂ nanoparticles (PHC/Ca²⁺/SiO₂ NPs) conductive hydrogels. Owing to the stable chemical and physical hybrid crosslinking networks and reversible non-covalent interactions, the PHC/Ca²⁺/SiO₂ NPs conductive hydrogel showed good conductivity (~3.39 S/m), excellent toughness (6.71 MJ/m³), high stretchability (2256%), fast self-recovery (80% within 10 s, and 100% within 30 s), and good fatigue resistance. The maximum gauge factor as high as 66.99 was obtained, with a wide detectable strain range (from 0.25% to 500% strain), the fast response (25.00 ms) and recovery time (86.12 ms), excellent negligible response hysteresis, and good response stability. The applications of monitoring the human's body movements were demonstrated, such as wrist bending and pulse tracking.

Keywords: hydrogels; toughness; wearable sensors.