Balancing Conductivity and Mechanical Robustness in Stretchable Elastomers via CNT –cu Nanowire Hybrid Percolation Networks

Stretchable conductors are essential for wearable electronics and soft devices. However, their performance is often limited by poor nanofiller dispersion and electrically unstable networks under repeated deformation. In this study, we report stretchable conductive polydimethylsiloxane (PDMS) nanocomposites based on a hybrid network of thin‐walled carbon nanotubes (CNTs) and copper nanowires (CuNWs), with carbon black (CB) composites prepared as a comparative system. FE‐SEM and SEM–EDX mapping confirmed relatively uniform CNT–CuNW distributions for CNT‐rich and intermediate hybrid compositions, whereas CuNW‐rich formulations exhibited Cu‐rich clustered regions. The CNT incorporation into the PDMS matrix significantly increased the tensile modulus/strength and viscoelastic moduli. Replacing CNTs with higher CuNW fractions reduced reinforcement due to decreased CNT scaffolding and poorer CuNW dispersion. In terms of electrical properties, the hybrids exhibited a composition‐dependent synergy. Partial replacement of CNTs with CuNWs increased bulk conductivity, reaching a maximum of ~25.8 S/m for CNT 3 wt%–CuNW 1 wt%. Under cyclic tensile deformation, the optimized hybrid system maintained low resistance, demonstrating a robust electromechanical response enabled by a well‐dispersed hybrid network. These results provide the relationships among filler ratio, dispersion, electrical conductivity, mechanical properties, and cyclic electromechanical stability in CNT–CuNW/PDMS composites.