title: A Novel Bioinspired Switchable Adhesive with Three Distinct Adhesive States.
abstract: A novel switchable adhesive, inspired by the gecko's fibrillar dry attachment system, is introduced. It consists of a patterned surface with an array of mushroom-shaped pillars having two distinct heights. The different pillar heights allow control of the pull-off force in two steps by application of a low and a high preload. For low preload, only the long pillars form contact, resulting in a low pull-off force. At higher preload, all pillars form contact, resulting in high pull-off force. Even further loading leads to buckling induced detachment of the pillars which corresponds to extremely low pull-off force. To achieve the respective samples a new fabrication method called double inking is developed, to achieve multiple-height pillar structures. The adhesion performance of the two-step switchable adhesive is analysed at varying preload and for different pillar aspect ratios and height relations. Finally, the deformation behavior of the samples is investigated by in situ monitoring.
authors.affiliation: INM - Leibniz Institute for New Materials Campus D2 2, 66123, Saarbrücken, Germany E-mail: elmar.kroner@inm-gmbh.de ; Saarland University Campus D2 2, 66123, Saarbrücken, Germany.
authors.forename: Paula Yagüe
authors.initials: PY
authors.lastname: Isla
authors.affiliation: INM - Leibniz Institute for New Materials Campus D2 2, 66123, Saarbrücken, Germany E-mail: elmar.kroner@inm-gmbh.de.
authors.forename: Elmar
authors.initials: E
authors.lastname: Kroner
keywords: bioinspired adhesives; patterned; pull-off; responsive; switchable