Shear adhesion between an elastica and a rigid flat surface

At the submicron scale, an elastic fiber adheres to a rigid surface when the surface forces induced by electrostatic, capillary, or van der Waals interactions exceed the elastic restoring forces for bending. Adhesion is aided by the application of a shear load to the base of the fiber, which will initiate or increase the length of side contact. The presence of a shear force is necessary for the attachment of a gecko-inspired nanofiber array adhesive, which spontaneously detaches once the shear load is removed. Treating the fiber as an elastica, we derive a relationship between fiber geometry, work of adhesion, applied shear load and length of side contact.