Dynamically Adaptive and Durable Poly(ionic liquid) Elastomer Enabled by Ion–Dipole Interactions for Underwater Sensing

Ion-conductive elastomers are pivotal for next-generation intelligent systems, yet their practical deployment is hindered by limited environmental stability, poor interfacial adaptability, and lack of self-healing capability. We report a solvent-free poly(ionic liquid) elastomer (PILE) synthesized via ternary copolymerization. The PILE exhibits a unique dynamic interfacial adaptation mechanism: fluorinated segments spontaneously enrich the surface to form a hydrophobic layer in air, while upon substrate contact, it autonomously reconfigures its interfacial composition, recruiting polar or fluorinated groups to enable robust adhesion to hydrophilic or hydrophobic surfaces, even underwater. Concurrently, the material features a dynamic network reinforced by ion–dipole interactions between imidazolium cations and −CF3 groups, serving as reversible sacrificial bonds. This design achieves an optimal balance between mechanical strength (tensile strength ∼ 550 kPa) and ultrahigh stretchability (∼1737% elongation), while enabling efficient room-temperature self-healing (98.9% recovery in 18 h). The hydrophobic PILE demonstrates exceptional environmental tolerance, with minimal weight loss (0.29% after 7 days) and negligible swelling, while maintaining stable ionic conductivity across a broad temperature range (3.58 × 10–2 to 1.74 × 10–1 S·m–1, 20–120 °C). The transparent elastomer (transmittance > 92%) functions as a durable strain/temperature sensor with reliable underwater performance, demonstrating a versatile design strategy for multifunctional ionic devices in soft robotics and wearable electronics.