Microbial foaming-based porous conductive hydrogel: Novel breathable strain sensor with low-temperature tolerance and degradability

Flexible, breathable, low-temperature tolerant, and degradable strain sensors have attracted substantial attention for varied applications in interactive wearable devices, artificial prosthetics, and intelligent robots. Herein, a novel breathable, low-temperature tolerant, degradable, and sensitive strain sensor is developed by microbial fermentation technology. The resulting strain sensor exhibited excellent gas permeability, about 13 times higher than that of unfermented hydrogel, reliable low-temperature resistance down to -20 °C, and robust degradability in water about 96 h. The strain sensor possessed good linearity (a correlation coefficient of 0.994) in an ultrawide sensing range (up to 200%), ultralow-detection limit (0.05%), fast response and recovery (36 ms), and high reproducibility (1000 cycles). Attributed to these tremendous strain sensing performances, the strain sensor is able to accurately monitor both subtle physiological activities and large human motions. Furthermore, these strain sensors can assemble into a 3D array for sensing tactile signals and mapping spatial stress distribution. This strain sensor also can apply to human-computer interaction to react the wrist movement. Sensors with breathability, low-temperature tolerance, and degradability in this work are expected to play a role in the preparation of various breathable strain sensors.