Flexible porous Gelatin/Polypyrrole/Reduction graphene oxide organohydrogel for wearable electronics

Conductive hydrogel-based flexible electronics have attracted immense interest in wearable sensor, soft robot and human-machine interface. However, the application of hydrogels in flexible electronics is limited by the deterioration of mechanical and electrical properties due to freezing at low temperature and desiccation after long-term use. Meanwhile, flexible electronics based on hydrogel are usually not breathable, which has a great impact on wearing comfort and signal stability in long-term sensing. In this work, an adjustable porous gelatin/polypyrrole/reduction graphene oxide (Gel/PPy/rGO) organohydrogel with high breathability (14 g center dot cmz center dot h-1), conductivity (5.25 S/m), mechanical flexibility, anti-freezing and long-term stability is prepared via the combination method of biological fermentation and salt-out toughening crosslinking. The sensor fabricated from the prepared porous organohydrogel exhibits excellent sensing sensitivity, fast response ability, and good endurance, which monitors both weak and intense human activities effectively like finger bending, elbow bending, walking and running, and tiny pulse beating. A pressure sensor array prepared from the porous organohydrogel detects pressure variation in 2D sensitively. Furthermore, the porous organohydrogel is utilized as flexible electrodes for the accurate collection , recognition of human physiological signals (EMG, ECG) and as an interface between human and machine. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

The application of hydrogels in flexible electronics is limited due to the deterioration of mechanical and electrical properties caused by freezing at low temperature and desiccation after long-term use. In this study, a porous organohydrogel with high breathability, conductivity, mechanical flexibility, anti-freezing and long-term stability was prepared using a combined method of biological fermentation and salt-out toughening crosslinking. The sensor fabricated from this porous organohydrogel exhibited excellent sensing sensitivity, fast response ability, and good endurance, making it suitable for monitoring various human activities and serving as a pressure sensor and human-machine interface.