Simple preparation of carboxymethyl cellulose-based ionic conductive hydrogels for highly sensitive, stable and durable sensors

Ionic conductive hydrogels have recently been increasingly studied due to their broad applications in sensing and flexible devices. Nevertheless, it is still a challenge to simply develop an ionic conductive hydrogel with satisfying comprehensive performance. Herein, ionic conductive hydrogels have been crosslinked by carboxymethyl cellulose and phytic acid via a simple one-pot approach to address these challenges. The unique double crosslinked microstructure ensures that the hydrogel has favourable mechanical performance, resilience (93%, similar to natural resilin), and recovery (20 min, after 7 cycles at 300%) along with less residual strain (6.7%, after 20 successive cycles at 125%). The hydrogel also exhibits outstanding ionic conductivity (6.0 S/m). The combined mechanical performance and ionic conductivity of the prepared hydrogel results in its remarkable performance when used in sensors. The hydrogel-based sensor displays superior sensitivity (GF of 2.86, at a strain of 600%), stability and durability towards both tensile and compressive deformation. In practical applications, the sensor demonstrates a broad strain window to detect both large and very small human activities, showing the excellent potential of this hydrogel in sensing and flexible devices. The approach in this work has also been optimized to potentially allow for large-area, low-cost fabrication.