Optimization of the electromechanical response properties of silicone rubber composite materials with a three-carbon topological structure

Strain sensors play a critical role in flexible electronics; however, conventional devices are often constrained by a narrow sensing range, low sensitivity, and intrinsic brittleness, which limit their practical applicability. In this study, a novel intelligent silicone rubber–based strain sensor was developed based on a force–electric coupling mechanism. The sensor incorporates a three-carbon topological conductive network (MCGVM), composed of carbon black (CB), graphene (GR), and multi-walled carbon nanotubes (MWCNTs) embedded in a silicone rubber (SR) matrix. The synergistic interaction among the three carbonaceous fillers promotes uniform dispersion within the matrix, resulting in a remarkably low percolation threshold (0.52 wt%) and enhanced interfacial interactions. Consequently, the MCGVM sensor exhibits an ultrawide strain sensing range of 342.62%, an exceptionally high gauge factor (GF = 43,207.05), and a stable, shoulder-effect-free resistance–strain response over 10,000 loading–unloading cycles. Furthermore, the underlying force–electric coupling behavior is systematically interpreted using a tunneling effect–based theoretical model. These results demonstrate the strong potential of MCGVM for high-performance, wide-range strain sensing applications in flexible electronics.