Interfacially Engineered MXene Hydrogel with Dual-Conductive Networks for High-Performance Multifunctional Sensing

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[figure]justification=raggedright, singlelinecheck=false, font=footnotesize \captionsetup[subfigure]justification=centering [1]¿m#1 Precise modulation of interfacial physical interactions in two-dimensional materials represents a key scientific challenge for achieving multifunctional integrated composites, with hydrogels serving primarily as functional carriers in this context. Using MXene as a model system, this study developed a polyacrylamide/polyvinyl alcohol/CaCl₂/AgNPs/proanthocyanidins/MXene (PPCAPM) composite through a multi-level interaction design, which exhibits autonomous moisture retention, high conductivity, and intrinsic adhesion. Molecular dynamics simulations reveal that proanthocyanidins (PA) enhance electrostatic repulsion between MXene layers, effectively counteracting van der Waals force-induced restacking. This results in an expansion of the interlayer centroid distance from 65–75 Å to 70–90 Å and a 48% increase in diffusion coefficient. MXene-supported silver nanoparticles, synthesized via PA-assisted reduction, establish stable electron transport pathways, while the incorporation of CaCl₂ enables simultaneous moisture self-regulation and the formation of ion conduction channels, yielding a dual-mode conduction mechanism. As a high-performance flexible sensor, the material maintains stable responsiveness under 663% strain and 190 kPa stress, with a conductivity of 1.84 S/m, a sensitivity factor of 3.73, and 80% water retention after 72 hours in ambient conditions. Experimental results confirm that the material can accurately capture signals ranging from large joint movements to subtle physiological activities such as electromyography (EMG) and electrocardiography (ECG) signals, demonstrating the feasibility and universality of constructing multifunctional integrated systems based on interfacial physical modulation of 2D materials. The proposed strategy of ”fine interfacial modulation” provides a theoretical foundation and methodological reference for the design of two-dimensional material composite systems toward next-generation wearable diagnostics and human–machine interaction.