Enhanced Mechanical Properties of Polyurethane Ionogels by Synergistic Interaction of Phase-Locking Ion and Hydrogen Bonds.

Ionogels are widely employed in various ionotronic applications. However, the advancement of ionogels with excellent mechanical properties presents significant challenges due to the interactions between ions and the strong polar sites in polymers, which hinder the interchain/intrachain hydrogen bonding interaction. In this work, ionic liquid (IL) with ureido is dispersed into polyurethane cationomer (PUC) solid network by swelling strategy to prepare PUC ionogels (PUCD/IL). The synergistic effects of phase-locked ions and hydrogen bonding between PUC chain and IL enhance the mechanical properties of the PUCD/IL, allowing the strength and elongation at break of PUCD/IL achieved ≈10.50 MPa and ≈1638.74%, which are enhanced by ≈162.50% and ≈80.74%, respectively, compared with the equivalent pure solvent-treated PUC (PUCD). Furthermore, the strength and elongation at break of the PUC ionogel prepared by the traditional solution blending method (PUCB/IL) are only 6.76% (0.71 MPa) and 25.87% (423.93%) of those of PUCD/IL, respectively. In addition, the PUCD/IL exhibits a wide sensing range (strain: ≈1000%; stress: ≈1000 kPa) and fast response time (104/154 ms), enabling stable and repeatable response to human movement for intelligent human posture monitoring applications. This study provides a strategy for the design and preparation of high-performance PUC ionogels for flexible sensors.