Biomechanics and Biomaterials Laboratory, Department of Applied Mechanics, School of Aerospace Engineering , Beijing Institute of Technology , Beijing 100081 , PR China.
Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry , Beihang University , Beijing 100191 , China.
Langmuir. 2018 Oct 16;34(41):12482-12487. doi: 10.1021/acs.langmuir.8b02550. Epub 2018 Oct 2.
Water droplet unidirectional transport on the asymmetric superhydrophobic surface has attracted much interest in theory analysis and applications, such as self-cleaning, antifogging, anti-icing, heat transfer, and so on. Different from the symmetrical performance on the uniform topographies, the droplets acting on the asymmetric surface exhibit an anisotropic state and easily roll off the surface along the special direction. This phenomenon is indicated by natural butterfly wings. The flexible asymmetrically arranged microstep induces the droplet to release along the outside radial (RO) direction and to pin against the RO direction. Here, inspired by butterfly wings, a kind of surface for superhydrophobic and unidirectional droplet transport is achieved by integrating the methods of soft lithography and enhanced crystal growth. The water droplet shows the anisotropic state on the biofabricated surface, and it rolls off easily along the step direction. The droplet is unidirectionally driven off the surface by the asymmetric surface tension force generated by the microstep topography. This experiment is significant for designing self-cleaning surfaces.
水滴在不对称超疏水表面上的单向输运在理论分析和应用方面引起了广泛的关注,如自清洁、防雾、防冰、传热等。与在均匀形貌上的对称性能不同,作用在不对称表面上的液滴表现出各向异性状态,并且容易沿特殊方向从表面滚落。这一现象在天然蝴蝶翅膀上有所体现。柔性不对称排列的微台阶促使液滴沿着外部径向(RO)方向释放,并与 RO 方向相贴合。在这里,受蝴蝶翅膀的启发,通过整合软光刻和增强晶体生长的方法,实现了一种超疏水和单向液滴输运的表面。在生物制造的表面上,水滴呈现各向异性状态,并且很容易沿着台阶方向滚落。液滴通过微台阶形貌产生的不对称表面张力被单向驱动离开表面。这项实验对于设计自清洁表面具有重要意义。