MXene triggered double conductive mechanism hydrogels for strain sensing with electromagnetic interference shielding performance

Highly conductive and super-tough acrylamide hydrogels are essential for the development of flexible electronics. However, the inherent electrical and mechanical deficiencies of polyacrylamide (PAM) impede their utilization in flexible electronics. To address this challenge, a novel double-crosslinking method for rapid gelation based on an MXene-initiated poly (acrylamide/vinylimidazole) (MPAV) system is presented in this paper. MXene rapidly initiated the copolymerization of acrylamide with ionic liquids and acted as a physical cross-linking point for dynamic and reversible physical interactions with the polymer chains. The copolymerization of ionic liquids solved the problem of MXene aggregation in the medium and enabled the ionic conductivity mechanism of directional movement of free ions inside the MPAV hydrogel. MPAV hydrogels exhibited high electrical conductivity (2.28 S/m), excellent electromagnetic interference shielding efficiency (SE_t > 35 dB), and sensitive strain sensing properties (maximum gauge factor: 14.69 and maximum sensitivity: 0.124 kPa⁻¹). The well-designed MPAV double crosslinked hydrogel also displays remarkable mechanical properties (elongation: 457 % and compressibility: 80 %) and self-healing capabilities.