Micro arch-bridge structured surface fabricated by kirigami-on-elastomer approach for liquid-dependent iso/anisotropic wetting

摘要

Thin-film/elastomer bilayer systems have been studied for the fabrication of micro-structured surfa-ces. Here, we report a fabrication technique for three-dimensional microstructures by using thin rib-bons partially attached to an elastomer substrate. This technique is an easy-to-use version of the conventional kirigami-on-elastomer approach. Parts of thin ribbons not attached to the elastomer substrate buckle under a fixed strain and form arch bridges with hollow spaces between the buckled ribbons and the elastomer substrate. We experimentally study the formation of the arch-bridge struc-ture by changing applied strains to provide physical insights and find that the arch-bridge structure is useful as a functional surface. Although the arch-bridge structure was made with one-micron-thick ribbons, the structure is significantly robust. Different from the conventional structured surfaces made of micro-pillars, the micro arch-bridge structure exhibits an isotropic or an anisotropic wetting property depending on a liquid placed on the substrate.