Reconfigurable Electrical Networks within a Conductive Hydrogel Composite

Soft materials that exhibit compliance, programmability, and reconfigurability can have a transformative impact as electronic skin for applications in wearable electronics/soft robotics. There has been significant progress in soft conductive materials; however, achieving electrically controlled and reversible changes in conductivity and circuit connectivity remains challenging. To overcome this limitation, a soft material architecture with reconfigurable conductive networks of silver flakes embedded within a hydrogel matrix is presented. The conductive networks can be reversibly created/disconnected through various stimuli, including current, humidity, or temperature. Such stimuli affect electrical connectivity of the hydrogel by controlling its water content, which can be modulated by evaporation under ambient conditions (passive dehydration), evaporation through electrical Joule heating (active dehydration), or absorption of additional water (rehydration). The resulting change in electrical conductivity is reversible and repeatable, endowing the composite with on-demand reconfigurable conductivity. To highlight this material's unique properties, it is shown that conductive traces can be reconfigured after severe damage and revert to lower conductivity after rehydration. Additionally, a quadruped robot is demonstrated that can respond to stimuli by changing direction following exposure to excess water, thereby achieving reprogrammable locomotion behaviors.

Automated summary

Soft materials with reconfigurable conductive networks show promising applications in electronic skin for wearable electronics/soft robotics. This study presents a soft material architecture with silver flakes embedded in a hydrogel matrix, allowing reversible creation/disconnection of conductive networks through various stimuli. The electrical connectivity of the hydrogel can be modulated by controlling its water content, resulting in reversible and repeatable changes in conductivity. Highlighting the material's unique properties, this study demonstrates the reconfiguration of conductive traces after severe damage and the achievement of reprogrammable locomotion behavior in a quadruped robot responding to excess water.