Recyclable Strong Tough Ionogels via the Synergy of Solvent-Induced Cross-Linking and Chain Entanglement

Abstract

Ionogels are promising soft materials for diverse applications due to their exceptional ionic conductivity, thermal stability, and nonvolatility. However, conventional ionogels often suffer from compromised mechanical properties due to the plasticizing effect of ionic liquids, limiting their suitability for load-bearing applications. In this study, we present a counterintuitive strategy in which a small amount of ionic liquid severs not as a plasticizer but as a key structural modifier. On one hand, the ionic liquid facilitates hydrogen bond-mediated cross-linking, eliminating the need for chemical cross-linkers and enabling full recyclability. On the other hand, its limited content allows for dense chain entanglements within the polymer network, significantly enhancing mechanical robustness. This interplay yields ionogels with extraordinary mechanical properties, including a fracture stress of 7.8 MPa, fracture toughness of 54 kJ/m², and a Young’s modulus of 46 MPa, while also imparting outstanding stretchability (780%) and broad-spectrum viscoelasticity (10^–6–10⁴ Hz). As a proof of concept, the ionogel was assembled into a soft armor, demonstrating exceptional noise-damping and impact-resistant capabilities. This work provides insights into harnessing solvent-mediated interactions to engineer mechanically robust and sustainable ionogels for advanced applications.