title: Humidity-enhanced wet adhesion on insect-inspired fibrillar adhesive pads.
abstract: Many insect species reversibly adhere to surfaces by combining contact splitting (contact formation via fibrillar contact elements) and wet adhesion (supply of liquid secretion via pores in the insects' feet). Here, we fabricate insect-inspired fibrillar pads for wet adhesion containing continuous pore systems through which liquid is supplied to the contact interfaces. Synergistic interaction of capillarity and humidity-induced pad softening increases the pull-off force and the work of adhesion by two orders of magnitude. This increase and the independence of pull-off force on the applied load are caused by the capillarity-supported formation of solid-solid contact between pad and the surface. Solid-solid contact dominates adhesion at high humidity and capillarity at low humidity. At low humidity, the work of adhesion strongly depends on the amount of liquid deposited on the surface and, therefore, on contact duration. These results may pave the way for the design of insect-inspired adhesive pads.
authors: 1] Institut für Chemie neuer Materialien and Zentrum für Physik und Chemie neuer Materialien, Universität Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany [2] Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany.
authors: Longjian
authors: L
authors: Xue
authors: Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany.
authors: Alexander
authors: A
authors: Kovalev
authors: Institut für Chemie neuer Materialien and Zentrum für Physik und Chemie neuer Materialien, Universität Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany.
authors: Anna
authors: A
authors: Eichler-Volf
authors: Institut für Chemie neuer Materialien and Zentrum für Physik und Chemie neuer Materialien, Universität Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany.
authors: Martin
authors: M
authors: Steinhart
authors: Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany.
authors: Stanislav N
authors: SN
authors: Gorb