Rice leaf and butterfly wing effect

Abstract

Fluid drag reduction and antifouling are of commercial interest (Bhushan and Jung 2011; Bixler and Bhushan 2012a, 2015). Many flora and fauna flourish in living nature due to their low drag and antifouling properties, with commonly studied examples including shark skin and lotus leaves. Inspired by shark skin and lotus leaves, Bixler and Bhushan (2012b) found that rice leaves and butterfly wings combine the shark skin and lotus effects. Sinusoidal grooves in rice leaves and aligned shingle-like scales in butterfly wings provide the anisotropic flow. Hierarchical structures consisting of micropapillae superimposed by waxy nanobumps in rice leaves and microgrooves on top of shingle like scales in butterfly wings provide superhydrophobicity and low adhesion. Various studies suggest that this combination of anisotropic flow, superhydrophobicity, and low adhesion leads to improved drag reduction, self-cleaning, and antifouling (Bixler and Bhushan 2012b, 2013a, d, 2014; Bixler et al. 2014). Bixler and Bhushan (2015) provide a review and details follow.