A sheet on deformable sphere: "wrinklogami" patterns suppress curvature-induced delamination

TL;DR

This paper demonstrates that tiny, smooth substrate deformations called 'wrinklogami' can significantly suppress delamination in thin elastic films on curved surfaces by enabling near-isometric configurations, inspired by origami principles.

Contribution

It introduces the concept of 'wrinklogami' patterns that promote asymptotic isometry, providing a novel mechanism to prevent delamination in curved elastic films.

Findings

Wrinklogami patterns suppress curvature-induced delamination.

Emergence of wrinklogami indicates a nontrivial isometry of the sheet.

The concept of asymptotic isometry broadens understanding of elastic sheet responses.

Abstract

The adhesion of a stiff film onto a curved substrate often generates elastic stresses in the film that eventually give rise to its delamination. Here we predict that delamination of very thin films can be dramatically suppressed through tiny, smooth deformations of the substrate, dubbed here "wrinklogami", that barely affect the macroscale topography. This "pro-lamination" effect reflects a surprising capability of smooth wrinkles to suppress compression in elastic films even when spherical or other doubly-curved topography is imposed, in a similar fashion to origami folds that enable construction of curved structures from an unstretchable paper. We show that the emergence of a wrinklogami pattern signals a nontrivial isometry of the sheet to its planar, undeformed state, in the doubly asymptotic limit of small thickness and weak tensile load exerted by the adhesive substrate. We explain how such an "asymptotic isometry" concept broadens the standard usage of isometries for describing the response of elastic sheets to geomertric constraints and mechanical loads.