Highly Stretchable, Self-Healable, Freezing-Tolerant, and Transparent Polyacrylic Acid/Nanochitin Composite Hydrogel for Self-Powered Multifunctional Sensors
Xin Jing, Peiyong Feng, Zhuo Chen, Zhihui Xie, Heng Li, Xiangfang Peng, Hao‐Yang Mi, Yuejun Liu
Abstract
To fulfill the current challenges in the hydrogel applications in wearable sensors including low sensitivity, lack of self-healing ability, and non-transparency, we synthesized a polyacrylic acid/nanochitin composite hydrogel with dual cross-linking networks for highly stretchable, transparent, self-healing, and anti-freezing sensors via an eco-friendly method. Dynamic metal-coordination bonds between Al3+ and carboxyl groups and the hydrogen bonds contributed to the excellent self-healing efficiency of the hydrogel (97%). The dual cross-linking networks provide the composite hydrogel with 400 kPa tensile strength. The hydrogel-based sensors could detect multiple external stimuli, demonstrating a high gauge factor of 2.36 with the strain range of 0–500% and an ultrabroad temperature detection range (−35 to 50 °C). Significantly, the composite hydrogel demonstrates an ultrasensitive thermal response with a sensitivity of 252 %/°C during the cooling process. Moreover, the composite hydrogel was also assembled into a triboelectric nanogenerator to act as a self-powered pressure sensor. Therefore, the developed hydrogel sensors fabricated via a facile and green preparation approach hold great potential for sustainable wearable sensors in electronic skins and personal healthcare.