Fig. 3: Images and graphs from the compression testing.

a Microscope image of an expanding hexagonal spacer before compression and b microscope image of the same sample after complete failure. c Stress vs. displacement curve from the Instron material tester for an expanding hexagonal sample, similar to (a, b). Note that large displacements measured by the materials tester are due to the deformations of the load cell and the test stand (see Supplementary Section S3). The spacer itself generally deformed by <1 μm, as determined from the capacitive measurements of the inter-electrode gap. d Stress vs. strain curve for a different sample of the wavy low-curvature design. All examples are for d = 4.2 μm and t = 800 nm