Electronic Upcycling of Corn Straw: Biobased Elastic Conductive Cross-linked Network Eco-friendly Hydrogels with multifunction for Flexible Wearable Sensors

The conductive hydrogels based on biomaterials have garnered much attention. However, the utilization of corn straw, an agricultural waste, as a gel substrate can achieve the recycling of agro-waste and the development of advanced electronic materials, which has a dual benefit strategy seems to be overlooked. In this study, a corn straw pith (CSP) based multifunctional conductive hydrogel (CSP-MCG) was prepared by introducing CSP, which presents oxygen-rich groups, into the three-dimensional crosslinking network system of the hydrogel. The CSP-MCG has mechanical elasticity (maximum tensile rate of 340%) and responsiveness to external environmental factors (mechanical strain, temperature, humidity): Under different tensile strain conditions, the fatigue response is stable and the sensitivity is high (GF=2.8, R2=0.996, Tres=0.075s);In temperature range 20℃-50℃, it exhibits great performance (R2=0.993, TCR=1.34%/℃, Tres=0.5s); Within the humidity range RH29%-79%, the signal changes steadily and the response time is short (Tres=0.2s). In addition, CSP-MCG not only exhibits responsiveness to various external stimuli, but also demonstrates the ability to differentiate between these stimuli based on variation trend in its resistance and capacitance. Due to its exceptional multi-functional sensing capabilities and environmental attribute (recyclability and degradability), CSP-MCG can be as green flexible electronic material in practical applications such as electronic skin, human-computer interaction and flexible wearable sensors.