Tunable spatially dependent wrinkling morphologies on pre-curved surfaces

Functional design and morphomechanics via wrinkles have received extensive attention due to its increasing applications in different fields such as smart materials, flexible electronics, and biomedical engineering. Here through a combination of experiments and nonlinear simulations, we demonstrate controllable spatially dependent wrinkling pattern of hard films on pre-curved soft substrates can be realized by tuning curvature and pre-stretch. We stamp an initially flat sheet onto a curved mold to obtain the pre-curved soft substrate, and a metal film deposited onto the substrate forms wrinkles after flattening the curved bilayer via subsequent removal of it from the mold. Various spatially distributed wrinkling patterns such as checkerboard, bead-chain, herringbone, radially or circumferentially oriented stripes are observed through numerical simulations, in good agreement with experimental observations. Such approach provides a strategy for tunable wrinkling patterns of a film by releasing the pre-bending of its underlying substrate. (C) 2021 Elsevier Ltd. All rights reserved.