Fig. 2: Mechanical characteristics of the VSMSC.

a, b Optical images and corresponding finite element (FE) analysis models of the VSMSC except for low modulus silicone encapsulation (a) bent at a radius of 3 mm and (b) stretched at 30%. Most of strain noted by the color maps is absorbed in the interconnectors instead of the islands. c–f Comparison of (c, d) the soft stacked and (e, f) solid designs when bending at a radius of 3 mm. The maximum strain (0.29%) of the soft stacked design is much lower than that (0.9%) of the solid design. g–j Comparison of (g–h) the soft stacked and (i, j) solid designs when stretching 100% of the interconnectors. The maximum strain (2.7%) of the soft stacked design is much lower than that (6.74%) of the solid design. k, l Strain distributions through the cross-sectional dimension of the soft stacked design (solid lines) and solid design (dashed lines) when (k) bending and (l) stretching. The strain at the front side (magenta) and the back side (blue) of the soft stacked design is confined between −0.37% and 0.29% for bending and between −2.42.% and 2.7% for stretching while the solid design has much higher strain (between 1.06% and 0.9% for bending, between −5.72% and 6.74% for stretching). m, n Measurement results of relative resistance of the fabricated VSMSC (m) for repetitive bending (bending radius: 3 mm) and (n) repetitive stretching (stretchability: 30%) up to 6000 cycles. (n = 6 samples each for bending and stretching, data presented as mean ± s.d).