Tough Hydrophobic Ionogel Fibers via Molecularly Engineered Phase Separation for Multi‐Scenario Sensing

Abstract

Highly stretchable gel fibers are increasingly critical given the growing miniaturization and adaptivity demands within flexible wearable devices. Current fiber‐based iontronics, however, exclusively rely on hydrogels with limited environmental tolerance. Moreover, most existing gel systems exhibit insufficient strength and toughness to meet fiber processing requirements. Inspired by the composite architecture of natural biomaterials (e.g., spider silk and human skin), we develop tough hydrophobic ionogel fibers (IGFs) through molecularly engineered polymerization‐induced phase separation. This strategy embeds rigid hydrogen‐bonded polyacrylamide‐rich nanophases within an elastic matrix, endowing IGFs with an exceptional toughness of 24.6 MJ/m 3 and a fracture strength of 4.5 MPa whilst retaining high stretchability of ∼900%. Crucially, the continuous soft phase establishes efficient ion channels, enhancing conductivity while overcoming the mechanics‐conductivity trade‐off in traditional gel systems. The incorporated fluoropolymer segments further confer outstanding underwater adhesion and self‐healing capabilities. As strain sensors, IGFs exhibit high sensitivity (GF = 11.5) and perform well under extreme conditions including high (100°C) or low (−40°C) temperatures, vacuum (1.325 kPa), high humidity (98%RH), and even underwater environments. This work addresses the scarcity of robust flexible sensors for harsh‐environment applications, thereby substantially broadening their operational scenarios.