Switchable origami adhesives

Abstract

Creating a reusable adhesive that can hold objects on a wall and can yet be easily removed al for researchers in the adhesives community for many years. Geckos and other climbing organisms demonstrate just this ability: to hold large loads (on-state) due to specialized digits and microstructures, yet they are also able to quickly peel their feet from a surface while climbing (off-state). Inspired by the simplicity of the gecko's geometric switching mechanism, we have investigated the use of origami design methods to create geometries that can transition from a stiff configuration to a more flexible and easily peeled configuration. Specifically, we examined three different origami designs (Kresling, Waterbomb and Ron Resch) fabricated in polycarbonate and supplemented with 3D printed structures. Although the polycarbonate could be coated with a commercial adhesive, we investigated the devices in contact with polydimethylsiloxane adhesive pads in order to chemically control interfaces and create a range of differing adhesion levels. We show that the devices are capable of moderate switching ratios (F_on/F_off up to ∼50). We give a simple model to aid design and provide many options for scaling design performance through size, adhesive strength or through repetition of the pattern beyond a single unit cell.