A Highly Robust Ionotronic Fiber with Unprecedented Mechanomodulation of Ionic Conduction

Abstract Stretchable ionic conductors are appealing for tissue‐like soft electronics, yet suffer from a tardy mechanoelectric response due to their poor modulation of ionic conduction arising from intrinsic homogeneous soft chain network. Here, a highly robust ionotronic fiber is designed by synergizing ionic liquid and liquid crystal elastomer with alternate rigid mesogen units and soft chain spacers, which shows an unprecedented strain‐induced ionic conductivity boost ( ≈ 10 3 times enhanced as stretched to 2000% strain). Such a surprisingly high enhancement is attributed to the formation of microphase‐separated low‐tortuosity ion‐conducting nanochannels guided by strain‐induced emergence of aligned smectic mesophases, thus allowing for ultrafast ion transport that resembles the role of “swimming lanes.” Intriguingly, the boosting conductivity even reverses Pouillet's Law‐dictated resistance increase at certain strains, leading to unique waveform‐discernible strain sensing. Moreover, the fiber retains thermal actuation properties with a maximum of 70% strain changes upon heating, and enables integrated self‐perception and actuation. The findings offer a promising molecular engineering route to mechanically modulate the ion transport behavior of ionic conductors toward advanced ionotronic applications.