How the Structure and Wettability Properties of Morpho peleides Butterfly Wings Can Be a Source of Inspiration

In this study, the wettability of Morpho peleides (M. peleides) wings is studied. Using a goniometer, the contact angles of ~136° were measured. Although few studies have provided a general overview of the static wettability properties of M. peleides and the particularly anisotropic morphology of their wings, a detailed analysis of wettability properties is proposed. The results indicate anisotropic wettability, with a sliding angle of 7° when the wings were tilted away from the insect's body and 29° when the wings were tilted toward the insect's body. The Extrand model, coupled with a hierarchical approach, was also employed to describe the wettability behavior of M. peleides wings and its relationship with the dual roughness scale of the wings. Owing to these models, it has been demonstrated that the micrometric scale of the wing structure is primarily responsible for the static wettability properties of the M. peleides, while the nanometric scale influences the dynamic wettability of the wing. Moreover, compared to the topography, the wing's chemistry has very little effect on the wettability properties of the M. peleides.