Fig. 2
From: Tree frog attachment: mechanisms, challenges, and perspectives
Geometrical model of the ventral toe pad epidermis in a tree frog with snout-vent-length ℓSV. A The approximately circular projected ventral pad area Ap (diameter dp) is B covered by polygonal epidermal cells with diameter dc, edge length ac, channel width wc, and apical surface area Ac. C Each cell accommodates polygonal nanopillars with diameter dn, channel width wn, and a distance Δr between dimple and nanopillar edge. D Enhancement (in %) of the wetted area by the micro- and nanochannels relative to Ap and composition of Ap (in %) assuming regular, hexagonal outlines of the epidermal cells and nanopillars. Inset: Definition of projected and wetted areas shown for a hexagonal pillar. CH channel, DI dimple, NP nanopillar