Solvent-Free MXene/Poly(ionic liquid) Composite Elastomers with Simultaneously Improved Mechanical and Electrical Properties for Sensing and Photothermal Applications.

Solvent-free ion-conducting elastomers exhibit distinct advantages over hydrogels and ionogels such as zero solvent leakage and high electrochemical stability. However, achieving simultaneous enhancements in both mechanical and ion-conducting properties remains a challenge due to the inherent trade-off in these properties. To overcome this trade-off, we prepared solvent-free ionic elastomers with favorable ionic conductivity and mechanical properties by incorporating MXene into ion-conductive poly(ionic liquid) networks. The elastomers with a suitable MXene content demonstrated a high ionic conductivity of 0.044 S/m at 30 °C and a tensile strength of 0.48 MPa. Structural analysis attributed the enhanced tensile strength to the nanofiller effect of MXene that electrostatically interacts with the poly(ionic liquid) matrix. Dielectric spectroscopy revealed that the addition of MXene facilitates extra pathways for ion transport, thereby improving the ionic conductivity. The solvent-free MXene/poly(ionic liquid) elastomers were utilized as strain sensors and photothermal materials, demonstrating potential applications for personal management and photothermal therapy.