Universal scaling laws for metallic wrinkling on soft spherical substrates

The surface wrinkling of metal films on spherical polydimethylsiloxane (PDMS) substrates was induced by thermal contraction. A novel scaling law among wrinkle wavelength, film thickness, and substrate radius was discovered experimentally and rationalized theoretically, with scaling exponent being constant and coefficient being material-dependent. The theoretical predictions agree well with the existing experimental data of other spherical shell/core systems, with shell/core modulus ratio spanning several orders of magnitude, indicative of the universality and robustness. The results shed new light on the wrinkling phenomenon of spherical surfaces and demonstrate a predictive pathway to create wrinkling patterns on demand. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

The surface wrinkling of metal films on spherical PDMS substrates is induced by thermal contraction. A novel scaling law among wrinkle wavelength, film thickness, and substrate radius was discovered experimentally and rationalized theoretically, showing universality and robustness across different materials. The results provide new insights into the wrinkling phenomenon of spherical surfaces and demonstrate a predictive pathway to create wrinkling patterns as needed.