Highly Stretchable, Tough, and Transparent Chitin Nanofiber-Reinforced Multifunctional Eutectogels for Self-Powered Wearable Sensors

Abstract

Traditional conductive hydrogels have disadvantages for wearable sensors, such as poor electrical conductivity, weak mechanical properties, narrow application temperature range, and required external power supply, which limit their wide application. However, manufacturing hydrogel sensors with excellent mechanical properties and self-adhesive, temperature-resistant, and self-powered properties remains a challenge. Herein, chitin nanofiber-reinforced eutectogels (CAANF) with self-adhesive, self-healing, transparent, environment tolerant, and good mechanical properties were obtained via a simple one-pot method with the deep eutectic solvent (DES) system composed of acrylic acid, acrylamide, and choline chloride (ChCl). High-density hydrogen bond networks between CAANFs can act as strong cross-linking sites, conferring high stretchability (1680%) and elasticity. Moreover, high-density hydrogen bond networks with dynamic reversibility can provide excellent self-healing and adhesion abilities. Due to the unique properties of DES, CAANF eutectic gels also exhibit good ionic conductivity and environmental resistance, allowing the sensor to be applied over a wide temperature range (−30 to 60 °C). Additionally, CAANF-based self-powered flexible sensors can be used to detect human movement, monitor health status, and transmit signals for the encryption and decryption of information according to the Morse code. This work expands the scope of portable applications in the field of wearable electronic devices.