Ultra-stretchable, high-adhesive, self-healable and remoldable hydrogel sensor with dynamic multi-interactions for multiscale motion detection, Braille transmission and temperature monitoring

Flexible wearable electronic sensor has attracted considerable interest due to their inherent advantages, but the multifield and high-precision applications require the development of unique and multifunctional material systems. Herein, carboxymethyl chitosan (CMCS)/sodium alginate (SA)/zwitterionic copolymer (SHA)/4-formylphenylboronic acid (Bn) ionic conductive hydrogel (CSSB) was designed and fabricated by a facile one-pot blending strategy with CMCS and SA as the gel matrix, SAH as the conductive filler and Bn as the dynamic crosslinker. CSSB ionic hydrogel exhibits outstanding mechanical, self-healing, remodeling and electrochemical properties (ultra-high stretchability of 23600%, fracture toughness of 7.01 MJ m−3, 96.6% strain self-healing efficiency at 30 °C for 15 min and electrical conductivity of 3.656 S/m) to satisfy the requirements of various application scenarios. The flexible wearable sensor based on the CSSB ionic hydrogel is demonstrated, and the excellent strain sensing properties endow the sensor to monitor multiscale human movements and to transmit Braille information. Moreover, the sensor can be designed as a temperature sensor with unique thermal sensitivity (-4.48%/°C), outstanding detection accuracy (R2 = 0.9988) and an extremely low detection limit (0.1 °C) for monitoring changes in human body temperature and variations in storage temperature during long distance transport. This work is expected to provide ideas for the next generation of environmental multi-sensory electronic skin and temperature detection electronics.