Ankle structure of the Tokay gecko (Gekko gecko) and its role in the deployment of the subdigital adhesive system

Abstract

The remarkable ability of geckos to adhere to smooth surfaces is often thought of in terms of external structures, including the branching setae that make contact with the surface producing van der Waals forces. Some geckos also exhibit unique movements of the distal segments of the limbs during locomotion and static clinging, including active digital hyperextension and considerable pedal rotation. During static clinging, geckos can exhibit considerable adduction/abduction of the pes while the crus and thigh remain firmly adpressed to the substratum. This decoupling of pedal adduction/ abduction from ankle flexion/extension and pedal long-axis rotation is a significant departure from pedal displacements of a typical lizard lacking adhesive ability. The

Analysis of the adhesion mechanism of functionalized carbon nanotubes by molecular dynamics simulation

“…Scientists have put forward many hypotheses to explain the strong adhesion of gecko bristles, including sucker force, electrostatic force, micro-interlocking force, capillary force, van der Waals (vdW) force and so on. [1][2][3][4][5] For example, Autumn et al conrmed that the adhesion of gecko bristles comes from the intermolecular force between keratin molecules of bristles and the contact surface, that is, the van der Waals force mechanism. 2,3 In recent years, Alibardi et al proposed that the adhesion of gecko sole bristles comes from the joint action of van der Waals force and electrostatic force, which is related to the biological tissue and chemical composition of the bristle surface.…”