title: Nested self-similar wrinkling patterns in skins.
abstract: Stiff thin films on soft substrates are both ancient and commonplace in nature; for instance, animal skin comprises a stiff epidermis attached to a soft dermis. Although more recent and rare, artificial skins are increasingly used in a broad range of applications, including flexible electronics, tunable diffraction gratings, force spectroscopy in cells, modern metrology methods, and other devices. Here we show that model elastomeric artificial skins wrinkle in a hierarchical pattern consisting of self-similar buckles extending over five orders of magnitude in length scale, ranging from a few nanometres to a few millimetres. We provide a mechanism for the formation of this hierarchical wrinkling pattern, and quantify our experimental findings with both computations and a simple scaling theory. This allows us to harness the substrates for applications. In particular, we show how to use the multigeneration-wrinkled substrate for separating particles based on their size, while simultaneously forming linear chains of monodisperse particles.
authors.affiliation: Department of Chemical Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA.
authors.forename: Kirill
authors.initials: K
authors.lastname: Efimenko
authors.forename: Mindaugas
authors.initials: M
authors.lastname: Rackaitis
authors.forename: Evangelos
authors.initials: E
authors.lastname: Manias
authors.forename: Ashkan
authors.initials: A
authors.lastname: Vaziri
authors.forename: L
authors.initials: L
authors.lastname: Mahadevan
authors.forename: Jan
authors.initials: J
authors.lastname: Genzer
mesh_terms: D003432:Cross-Linking Reagents / Q000494:pharmacology; D006801:Humans; D008853:Microscopy; D008855:Microscopy, Electron, Scanning; D015233:Models, Statistical; D036103:Nanotechnology; D010126:Ozone; D012867:Skin / Q000473:pathology*; D015595:Skin Aging; D017768:Skin, Artificial; D013053:Spectrophotometry; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D010126:Ozone