Synergistic Regulation of Hybrid Conductive Network and Interface in VMQ/MWCNT/GNP Composites for Reliable Strain Sensing

Flexible strain sensors require conductive elastomers with both mechanical robustness and stable electromechanical performance under cyclic deformation. In this study, a silicone rubber (VMQ)-based conductive elastomer was developed by combining a hybrid MWCNT/GNP filler network with KH550-mediated interfacial engineering. An optimized oxidized MWCNT was selected as the primary conductive filler, showing an electrical percolation threshold of 4–6 phr in VMQ. At a fixed total filler loading of 8 phr, the optimal MWCNT/GNP ratio was determined to be 7:1, yielding a tensile strength of 9.8 MPa, a tear strength of 65.7 N/mm, and a volume resistivity below 10 2 Ω·cm. XPS, EDS, TGA, SEM, and RPA results confirmed that KH550 modification improved filler dispersion, enhanced filler–matrix adhesion, and stabilized the conductive network. The optimized sensor exhibited a working strain range of 0–120%, gauge factors of ∼8–10 at 0–60% strain and ∼30 at 120% strain, response/recovery times of 619/670 ms, a baseline drift of 11.2%, a hysteresis degree of 9.4%, and stable operation over 5000 cycles at 60% strain. This work provides an effective strategy for designing silicone-rubber-based conductive elastomers with balanced mechanical strength and sensing reliability.