Confinement-Locking Strategy Enables Ionogels With Remarkable Mechanical Robustness and Fatigue Resistance.

Abstract

Ionogels with favorable mechanical robustness, high conductivity, and excellent resistance to tear and fatigue are crucial for portable energy devices and/or flexible electronics. However, the intrinsic plasticizing effect and network dilution caused by ionic liquids (IL) compromise their mechanical robustness. Herein, a confinement-locking strategy is developed to produce mechanically robust and fatigue-resistant phase-separate ionogels. First, a portion of soft segments is confined within the hard domains to buffer stress and facilitate hydrogen bonding (H-bonding) assemblies reorganization. Second, the IL are confined within soft phases, which eliminates the interference with hard segments and consequently enhances the stability of H-bonding networks. The synergistic effects of robust H-bonding networks, extensive supramolecular interactions between soft segments (polycaprolactone, PCL) and IL, strain-induced crystallization of PCL, and stress-damping by confined soft segments endow the ionogel with an exceptional combination of tensile strength (∼45.4 MPa), fracture toughness (256.1 MJ·m^- ³), elongation at break (1576.6%), elastic recovery (>91%), ionic conductivity (1.04 mS·cm^-1), tear strength (∼108.1 kJ·m^- ²), and a record-high fatigue threshold (8796 J·m^- ²), enabling the ionogel with great potential in perceptive artificial ligaments.