ABSTRACT
Anisotropism is one of the most important properties of a patterned solid surface. The anisotropic rough surface results in special wetting and dewetting characteristics in different directions. One example is the anisotropic dewetting phenomenon on the superhydrophobic rice leaf surface. The sliding angle (SA) of a water droplet is greatly influenced by the anisotropic arrangement of the papillae on the rice leaf [1]. The anisotropic wettability has drawn much attention and has been applied for fabrication of selfassembling patterned surfaces [2], submicrometric channel lattices with alternating wettability [3] and rice-like aligned carbon nanotubes (ACNT) film [4]. The anisotropic dewetting property may bring interesting insights into design of lossless liquid transportation channels and novel microfluidic valves, in which liquids can be driven in a preferred direction. Insect wing is an ideal bio-template for artificial fabrication due to some excellent properties, such as attractive iridescence, superhydrophobic characteristics and quick heat dissipation ability [5]. In the present paper we investigated the anisotropism of the rough surface on the moth wings and discussed the wetting mechanism from the perspective of biological coupling. This work can not only promote our understanding of anisotropic wetting phenomenon on
bio-surfaces, but provide inspiration for design and preparation of smart fluid-controllable interface and directional self-cleaning material.
