Fig. 5From: Tree frog attachment: mechanisms, challenges, and perspectivesSchematic generation of van der Waals (vdW) forces (F⊥,vdW, F∥,vdW) between ventral toe pad epidermis (green) and substrate (grey) for a system-specific Hamaker constant AH. VdW interactions occur in regions of close pad-substrate contact (red)Back to article page