A Highly Sensitive and Self-Healable Hydrogel System Filled with Multidimensional Nanomaterials for Strain and Pressure Sensing Applications

Sensors and their interconnected networks form vital technological and economic frameworks for industries worldwide, finding applications in consumer electronics, medical care, military technology, environmental surveillance, infrastructure management, and numerous other fields. Piezoresistive strain and pressure sensors have recently attracted significant interest in monitoring daily health conditions and advancing robotics research owing to their straightforward device designs and self-powered characteristics. Hydrogels with deliberately engineered architectures and tunable properties are regarded as intelligent materials offering multifunctional potential, especially for applications in flexible sensing technologies. Herein, for the first time, we have fabricated a self-healing, self-adhesive, and highly sensitive hydrogel consisting of dimensionally different conducting fillers (carbon nanotube: CNT, carbon nanohorn: CNH, reduced graphene oxide) for strain and pressure sensing applications. On mixing the conducting fillers, it is interesting to note that the CNH particles are exclusively attached to the CNT and the CNH-decorated CNTs are oriented inside the gallery of rGO flakes. The unique horn-like morphology of CNH promotes the conductivity and sensing performance of the hydrogel nanocomposites. The maximum sensitivity, i.e., gauge factor (GF) was obtained at ∼27 at a very low loading of combined nanoparticles (0.9 wt %). Therefore, the developed multidimensional nanofiller-incorporated hydrogels, exhibiting excellent stretchability, remarkable elasticity, self-repairing ability, and superior sensitivity, represent highly promising candidates for constructing advanced flexible sensors.