Development of supramolecular ionic gels with self-healing capability and biodegradability using a bioderived ionic...

Gels are promising candidates for environmental sensing and implants because of their high stretchability, ionic conductivity, and low toxicity toward the environment and human body. Self-healing gels can recover their mechanical and electrical properties after rupturing under environments with harsh mechanical stress. However, current self-healing gels rely on healing agents, metal ions, or dynamic bonding; these materials exhibit toxicity and nonbiodegradability, hindering their use in environmental sensing and implant applications. Herein, we developed supramolecular ionic gels (SIGs) with self-healing capability and biodegradability through the physical crosslinking of poly(vinyl alcohol) (PVA) and the bioderived ionic liquid (IL) choline lactate. Fourier-transform infrared spectroscopy and wide-angle X-ray scattering revealed that the IL and PVA formed hydrogen bonds, thereby resulting in nanocrystalline structures in the SIGs. After cutting, dynamic bonding helps self-healed SIGs recover fracture stress and strain by 39% and 45%, respectively, compared to pristine SIGs. Furthermore, hydrogen bonding is a reversible reaction that enables ruptured SIGs to reconfigure their shapes after tensile-stress tests. The reconfigured SIGs involve fracture stress and strain comparable with those of the initial SIGs. This study provides insights into bio/ecoresorbable electronics with high mechanical robustness, which can help develop transient devices for wearables, implants, and environmental sensing.