Dual Strong Interfacial Interaction-Mediated Supramolecular Ionogel Based on Modified Silk Fibroin Nanofibers for Ultratoughness and Multifunctionality

The integration of excellent mechanical performance with multifunctionality is a permanent pursuit for gels. In this work, a double modification sequencing in time of silk fibroin nanofiber (SNF) is adopted to achieve this for 2betaine:tartaric (BTB)-based ionogel (ABSH). Initially, the enhanced interfacial interaction between 4-hydroxybutyl acrylate glycidyl ether-modified SNF (SNF-4H) and BTB elevates SNF dispersity in the matrix. Subsequently, both the in situ interfacial enhancement and the elastic-state supramolecular network with no significant chain entanglement in the polymer phase are realized simultaneously by leveraging the kinetic impedance of polyacrylamide chain growth in BTB. By controlling the content of SNF-4H, the mechanical properties of ABSH ionogels can be effectively tuned. In particular, ABSH0.5% exhibits the highest tensile strength (10.05 MPa), a large elongation at break of 2210%, and ultrahigh toughness (172.12 MJ·m–3), increasing by 2692%, 70%, and 3795% compared with its hydrogel counterpart, respectively. It displays excellent environmental stability to withstand extreme temperatures and proper humidity, convenient recyclability, good crack resistance, and rubber-like impact resistance. Furthermore, its temperature sensing exhibits a broad operating range (−78.5 to 80 °C) with a maximum Temperature Coefficient of Resistance (TCR) of about −2.11% °C–1. This work affords an insight into high-performance ionogels with multifunctionality utilizing synchronous regulation of nanofiber reinforcement and polymer matrix in ionic liquid.