Hydrophobicity of Feather-Inspired, 3D-Printed, Polymeric Materials

Abstract

Feathers can vary hydrophobicity through differences in their microstructure geometry. These microstructures, known as barbs and barbules, can be emulated through 3D-printed materials at an enlarged scale to probe how different parameters of feather-like ridges influence hydrophobicity. The design includes five three-millimeter-wide circular samples featuring barbule-like ridges with different widths and angles. To characterize hydrophobicity, a two-microliter drop of water is placed on a sample surface, and a goniometer measures the mean contact angle (MCA), where higher mean contact angles indicate greater hydrophobicity. Wider ridges decreased hydrophobicity quadratically, with a leading coefficient of (-2.37 ± 0.92)×10^(-3) º/µm^2, while steeper angles increased hydrophobicity linearly, with a slope of (7.0 ± 3.8)×10^(-1), which is consistent with the theory behind feather hydrophobicity.