A Superstretchable and Conductive Polyurethane Elastomer via Solvent-Free Bulk Fabrication

Polyurethane elastomers (PUEs), composed of soft and hard segments, exhibit versatile mechanical properties and broad applications but face inherent limitations when incorporating irreversible covalent cross-linking bonds. These bonds, while enhancing structural stability and strength, drastically reduce elongation at break, hinder self-healing capabilities, and complicate functionalization due to solvent-processing challenges. To address these issues, we propose a quasi-prepolymer method integrating dynamic disulfide bonds and IPDI-based semirigid chain segments, which significantly improves chain mobility and deformation capacity. By synergizing ionic liquid-mediated interactions (fluorine-sulfonyl-cation-radical bridges) with a 330N-stabilized irreversible covalent network, we develop a solvent-free, bulk-polymerized superstretchable conductive elastomer. Remarkably, the material achieves an unprecedented elongation at break (∼9100%) with excellent resilience (100% recovery), self-healing under complex environments, and structural stability (against high temperature and solvents). Furthermore, it demonstrates wide temperature adaptability (−20 to 25 °C) and strain-sensitive conductivity (0.5%–2500% strain), enabling applications in low-frequency vibration sensing and large-scale tensile monitoring. This work overcomes the traditional thresholds of irreversible chemical cross-linking, offering a promising approach for designing high-performance elastomers in the service of major equipment with intelligent functionality.