Reconfigurable Electrical Networks within a Conductive Hydrogel Composite. Issue 14 (2nd March 2023)

• Record Type: Journal Article
• Authors: Ohm, Yunsik; Liao, Jiahe; Luo, Yichi; Ford, Michael J.; Majidi, Carmel
• Is Part Of: Advanced materials. Volume 35:Issue 14(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-02
• Subjects: conductive hydrogel composites -- reconfigurable conductors -- reversible conductive networks -- soft conductive materials; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202209408
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: 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. Abstract : Soft conductors coupled with reversible electrical conductivity can enable new functions in wearable electronics and soft robotics. In this work, a reconfigurable conductive hydrogel composite is developed, which is made of silver flakes, polyacrylamide, and alginate hydrogel. By simply applying dehydration and rehydration treatments, the material can achieve reversible electrical conductivity. This reconfigurability can help the material to recover from severe damage or control locomotion of a legged robot.