Gradient Wetting Transition from the Wenzel to Robust Cassie-Baxter States along Nanopillared Cicada Wing and Underlying Mechanism  

作　　者：Heng Xie Hanxiong Huang 

机构地区：[1]Lab for Micro Molding and Polymer Rheology,Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing and Key Laboratory of Polymer Processing Engineering(Ministry of Education),South China University of Technology,Guangzhou 510640,China

出　　处：《Journal of Bionic Engineering》2020年第5期1009-1018,共10页仿生工程学报（英文版）

基　　金：Financial support provided by the National Natural Science Foundation of China(Grant No.51533003);the Natural Science Foundation of Guangdong Province(Grant No.2016A030308018);the Guangzhou Municipal Science and Technology Project(Grant No.201807010088);the Opening Project(KFKT1805)of Key Laboratory of Polymer Processing Engineering(Ministry of Education)are gratefully acknowledged.

摘　　要：Gradient wettability is important for some living organisms.Herein,the dynamic responses of water droplets impacting on the surfaces of four regions along the wing vein of cicada Cryptotympana atratafabricius are investigated.It is revealed that a gradient wetting behavior from hydrophilicity(the Wenzel state)to hydrophobicity and further to superhydrophobicity(the Cassie-Baxter state)appears from the foot to apex of the wing.Water droplets impacting on the hydrophilic region of the wing cannot rebound,whereas those impacting on the hydrophobic region can retract and completely rebound.The hydrophobic region exhibits robust water-repelling performance during the dynamic droplet impact.Moreover,a droplet sitting on the hydrophobic region can recover its spherical shape after squeezed to a water film as thin as 0.45 mm,and lossless droplet transportation can be achieved at the region.Based on the geometric parameters of the nanopillars at the hydrophilic and hydrophobic regions on the cicada wing,two wetting models are developed for elucidating the mechanism for the gradient wetting behavior.This work directs the design and fabrication of surfaces with gradient wetting behavior by mimicking the nanopillars on cicada wing surface.

关 键 词：cicada wing nanopillared surface BIOMIMETIC gradient wetting transition dynamic wetting behavior 

分 类 号：Q811[生物学—生物工程] V21[航空宇航科学与技术—航空宇航推进理论与工程]