当前位置:
莲叶效应

关键字

莲叶效应;显微-纳米梯度结构;超疏水;自清洁

词条简介

   1997年,德国波恩大学植物学家Wilhelm Barthlott教授发现,当水滴滴在荷叶表面上,水滴在荷叶表面变成了滚动的水珠,带走荷叶表面的尘土等污染介质,使表面始终保持一尘不染的状态。这就是荷叶效应。研究发现,荷叶表面大量微米级乳突结构及纳米级低表面能蜡质晶体共同构成微纳分级结构。而足够的粗糙度与低表面能化学成分的协同作用使荷叶具有高接触角与低滚动角,呈现出超疏水自清洁状态。目前,在建筑、纺织、航空、通讯等领域均已得到应用。

原型介绍

“莲出淤泥而不染”。荷叶是睡莲科多年生具根茎的水生植物,喜温暖、喜水,叶类圆盾形,全缘或稍成波状,浮于水面之上,表面不易残留污染物。SEM图像显示,荷叶表面覆盖着许多直径为5-9μm的乳突结构,而且,微米级乳突结构上又覆盖着平均直径为124.3 ± 3.2 nm的纳米结构分支,构成微纳分级结构。“荷叶效应”为仿生润湿性功能表面与结构设计提供了极佳的参照。

原理介绍

荷叶表面微米级乳突与纳米级蜡质晶体结构间的凹槽处捕获空气,从而形成“空气垫”,产生负压,使得水滴在与表面接触过程中并未完全浸入表面的粗糙结构,具有较高的水接触角及极小的滚动角,有效阻止荷叶表面被水润湿,呈现出优异的超疏水性能及自清洁效应。


image.png

1a)荷叶光学图像;(b)表面微观形貌(SEM图像);(c)表面水滴滚动状态;(d)润湿机制图(Cassie模型)。

工程应用

仿照荷叶效应,所制备出的仿生超疏水表面呈现出自洁、防污、防冰、减阻、防腐等特性,在建筑、纺织、航空、通讯等领域都具有十分广阔的应用及发展前景。

参考文献

[1]   Barthlott W, Neinhuis C. Purity of the sacred lotus, or escape from contamination in biological surfaces. Planta, 1997, 202(1): 1-8.

[2]   Feng L, Li S H, Li Y S, et al. Super-Hydrophobic Surfaces: From Natural to Artificial. Advanced Materials, 2002, 14: 1857-1860.

[3]   Zhang J H, Wang J M, Zhao Y, et al. How does the leaf margin make the lotus surface dry as the lotus leaf floats on water? Soft Matter, 2008, 4, 2232–2237.

[4]   Roach P, Shirtcliffe N J, Newton M I. Progess in superhydrophobic surface development. Soft Matter, 2008, 4(2):224.

[5]  Jiang L, Zhao Y, Zhai J. A Lotus-leaf-like superhydrophobic surface: aporous microsphere/nanofiber composite film prepared by electrohydrodynamics. AngewandteChemie-Interational Edition, 2004, 43(33):4338-4341.

[6]  Liu K S, Yao X, Jiang L. Recent developments in bio-inspired special wettability. Chemical Society Reviews, 2010, 39(8):3240.

[7]  FürstnerR, Barthlott W, Neinhuis C, Walzel P. Wetting and self-cleaning properties of artificial superhydrophobic surfaces. Langmuir, 2005, 21(3):956-961.

[8] BharatB,Jung Y C. Natural and biomimetic artificial surfaces for superhydrophobicity, self-cleaning, low adhesion, and drag reduction.Progress in materials science, 2011, 56(1): 1-108.

[9]   Patankar N A. Mimicking the Lotus Effect:  Influence of Double Roughness Structures and Slender Pillars. Langmuir, 2004, 20(19):8209.

[10]  Latthe S S, Terashima C, Nakata K, Fujishima A. Superhydrophobic Surfaces Developed by Mimicking Hierarchical Surface Morphology of Lotus Leaf. Molecules, 2014, 19(4):4256-4283.

[11]  Koch K, Bhushan B, Jung Y C, BarthlottW. Fabrication of artificial Lotus leaves and significance of hierarchical structure for superhydrophobicity and low adhesion. Soft Matter, 2009, 5(7):1386.

[12]   Wang ST, Liu KS, Yao X, Jiang L. Bioinspired surfaces with superwettability: new insight on theory,design, and applications.Chemical Reviews, 2015, 115 (16): 8230-8293.

[13]  https://baike.sogou.com/v628402.htm


领域专家

   Wilhelm Barthlott

 江雷


创建人

李淑一,孙航