(a–f) Addition of surfactant/water solution results in a phase-separated morphology consisting of an elastic core topped by an Ag-dense surface layer. Optical microscopy and SEM images. In SEM images, bright areas correspond to Ag-rich phases, and the dark areas to non-conductive elastomeric regions. Upper row (a–c) without surfactant. Lower row (d–f) with surfactant. Left column (a,d) optical micrographs. Scale bars, 200 μm. Middle column (b,e) top-surface SEM images. Scale bars, 10 μm. Right column (c,f) cross-sectional SEM image. Scale bars, 10 μm. (g–l) Cross-sectional ToF-SIMS images. Upper row (g–i) without surfactant. Lower row (j–l) with surfactant. Left column (g,j) optical micrographs corresponding the ToF-SIMS images. Middle column (h,k) ToF-SIMS images of Ag. Right column (i,l) ToF-SIMS images of surfactant. Scale bars, 200 μm. Addition of surfactant reduces Ag signal as the surfactant binds to the Ag surface and is responsible for increasing the affinity between Ag flakes and fluorine rubber matrix. (m–o) Top-surface SEM images of stretched elastic conductors. (m–o) are elastic conductors stretched by 0%, 100% and 200%, respectively. Scale bars, 20 μm.