Fig. 2: Mechanical properties of the microstructured interface and mechanisms for the tough interface.

a Young’s moduli of pure PDMS, PDMS-CNTs (2 wt% CNTs) dielectric layer, and PDMS-CNTs (7 wt% CNTs) electrode. Comparisons of b, interfacial toughness and c, shear strength between a microstructured non-bonded interface, a microstructured bonded interface without interlinks, a flat bonded interface with crosslinks, and a microstructured bonded interface with interlinks. d SEM image of the microstructured interface under peeling, showing cohesive ruptures of the microcones marked by dashed ellipses. A schematic illustration of the peeling test is shown at left. e Sequential optical images of the microconed interface during in-situ stretching, showing a rupture strain of >200% that enables significant energy dissipation. f Schematic illustrations of brittle rupture of bulk PDMS and discrete rupture of a microstructured interface. g SEM images of the sensor under (from left) twisting, bending, and stretching, showing stable bonding between the microcones and the dielectric layer.