利用射频等离子体刻蚀法在不同刻蚀时间得到的聚丙烯扫描电子形貌图: ( a) 0 min, ( b) 30 min, ( c) 60 min, ( d) 90 min,( e) 120 min, ( f) 180 min
Chen等利用纳米球刻蚀的方法首先得到了排列整齐的单层聚苯乙烯 (PS)纳米 珠阵列 ,再用氧等离子体处理以进一步减小纳米珠的尺寸从而得到粗糙表面。 在其表面覆盖 20nm厚的金膜并用十八硫醇(ODT)进行修饰可以增强其疏水性 。通过调整 PS纳米珠的直径 (440-190 nm)可以控制表面接触角的大小 (132168° )。
For smooth, flat, uniform solid surface, the highest contact angle is only 119º 。
Real solid surface with concaveconvex structure
Wenzel model
Cassie model
Antifrost
Antifogging surfaces

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Oil−water separation
局部 放大
Supperrepellent material in nature
出淤泥而不染， 濯清涟而不妖。
--宋.周敦颐《爱莲说》

cosθ=(γSV –γSL)/ γLV
Interfacial tension: γSV 、 γSL 、 γLV
Hydrophobic surface
The surface free energy of materials is related to the species and the concentration of the functional surface groups
Sliding angle α Very large
Sliding angle α Very small
Self-cleaning effect
Dirt

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Higher CA
Smaller SA
Supperrepellent surface
3、The fabrication of Supperrepellent surface
PAN Nano fiber material
Wenzel model
Increasing the contact area between liqiud and solid
Cassie model
Decreasing the contact area between liqiud and solid

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Firstly, the fabrication of artificial structured surface. Several artificial structured surfaces have been disgined. If these nanopillar and mushroom shaped nanopillars array with piece of 10 mm×10 mm can be prepared by electroplate copper or nickel nanopillars?
Butterfly wings

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2、 The theoretics of Supperrepellent material
Young’s equation
Wettability
Wenzel model
Cassie model
Yong’s equation
Functional surface
•
Hydrophilic groups: —OH、—CHO、 —COOH、—NH2 • Hydrophobic groups： —CnH2n+1、 —CH=CH2、 —C6H5、—X、—NO2 —CF3
Fluorinated polymer
CH2 (36 dyn cm-1) > CH3 (30 dyncm-1) > CF2 (23 dyn cm-1) > CF3 (15 dyn cm1)
A wide spectrum of applications

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soy sauce

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Water collector in the desert
Antifouling coating
Superhydrophobicity
Water contact angle (WCA) larger than 150°and extremely low WCA hysteresis or sliding angle less than 10° .
Sliding angle
mg(sinα)/ω =γ (cosθa-cosθr) θa –Advancing contact angle, θr –Receding contact angle, m-The quality of water drop， g-Acceleration of gravity ， ω-Diameter of water drop， γ-Surface Energy of water drop。 m，g，ω，γ are constant ，then： sinα∝cosθa – cosθr.
For smooth, flat, uniform solid surface, the relationship between contact angle and surface energy can be described by Yong’s equation (Thomas Young, 1805 ) :
氧等离子体处理后的超疏水 PS纳米珠阵列表面

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Chemical vapor deposition
江雷等利用化学气相沉积法 (CVD)在石英基底上制备了各种图案 结构的阵列碳纳米管膜 , 结果表明 , 水在这些膜表面的接触角都大于 160°, 滚动角都小于5°, 纳米结构与微米结构在表面的阶层排列被认 为是产生这种高接触角、低滚动角的原因。
Wenzel model：
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Cosθ*=
r(SV - SL )

=r COS θ
LV
Real contact area r Apparent contact area
1
Wenzel model源自Cosθ*=r(SV - SL )

=r COS θ
LV
Providing θ =110º ，if r>0.53， θ* will be larger than 150º
The reason of choosing
fluorosilicone
Low surface energy and high surface-active of CF3 group Improves the adhesion and compatibility
self-assembly
Fabrication
Roughening a hydrophobi c material
Modifying a rough surface’s chemical components
Turning a Surface Super-Repellent Even to Completely Wetting Liquids

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Antifouling coating
Low surface energy coating for mitigating marine biological fouling
Drag reduction
Self-cleaning materials
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Supperrepellent material
1 Wettability
Wettability is a fundamental property of material surfaces
Young’s equation: cosθ=(γSV –γSL)/ γLV
Hydrophobic: θ›90 ° ; Hydrophilic： θ‹90 °.

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Secondly, modify its components by surface fluorination.

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Lastly, the fabrication of hierarchical structures. If the property of above structured surface after surface fluorination can not meet superhydrophobic or superhydrophilic requirement, I will increase surface roughness by preparing hierarchical structures on above artificial structured surface.
Cassie model
Cassie model
LOGO Providing CA between liqiud and air is 180° Area fraction f=Σa/Σ(a+b) Cosθ’= fcosθ+(1-f)cos180° = fcosθ+f-1 let’s assume that θ =110º ， if f is less than 0.2, θ’ will be larger than 150º .