Coupled Electronic and Ionic Conductivity in Strain‐Stiffening Hydrogels
Md Al Raihan, Mark M. A. Mikhail, Khaled M. Hijazi, Hessameddin Yaghoobi, John P. Frampton, Vahid Adibnia, Michael S. FreundABSTRACT
Advanced bioelectronics require soft materials that mechanically mimic tissues by exhibiting nonlinear mechanics and seamlessly bridge ionic signals in tissues and electronic signals in circuits. Creating conductive hydrogels with percolative electronic pathways that show tissue‐mimetic strain‐stiffening behavior represents a promising strategy to potentially address this need. Here, we report a composite hydrogel of poly(vinyl alcohol) (PVA) and poly(aniline boronic acid) (PABA) that exhibits strain‐stiffening mechanical behavior with mixed ionic and electronic conduction. Dynamic self‐healing boronic‐ester crosslinks that impart strain‐stiffening also facilitate the formation of a percolative network of conjugated conductive polymers during gelation, providing a continuous pathway for electronic transport ( σ e ∼ 10 −5 –10 −3 S m −1 ) alongside ionic conductivity ( σ i ∼ 1–10 S m −1 ). As a result, deformation directly modulates the electronic resistance, displaying a distinct resistance‐stabilization plateau that coincides with the onset of strain‐stiffening, suggesting a transition from geometry‐limited to alignment‐assisted charge transport within the network. By unifying adaptive tissue‐like mechanics with dual conduction, this system offers a promising avenue for developing soft, mechanically resilient materials capable of continuous electromechanical transduction.