Contact Angle Hysteresis of Non-Flattened-Top Micro/Nanostructures

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• 作者：Sona Moradi ; Peter Englezos ; Savvas G. Hatzikiriakos
• 刊名：Langmuir
• 出版年：2014
• 出版时间：March 25, 2014
• 年：2014
• 卷：30
• 期：11
• 页码：3274-3284
• 全文大小：730K
• 年卷期：v.30,no.11(March 25, 2014)
• ISSN：1520-5827

文摘

A two-dimensional (2D) thermodynamic model is proposed to predict the contact angle (CA) and contact angle hysteresis (CAH) of different types of surface geometries, particularly those with asperities having nonflattened tops. The model is evaluated by micro/nano sinusoidal and parabolic patterns fabricated by laser ablation. These microstructures are analyzed thermodynamically through the use of the Gibbs free energy to obtain the equilibrium contact angle (CA) and contact angle hysteresis (CAH). The effects of the geometrical details of two types of microstructures on maximizing the superhydrophobicity of the nanopatterned surface are also discussed in an attempt to design surfaces with desired and/or optimum wetting characteristics. The analysis of the various surfaces reveals the important geometrical parameters that may lead to the lotus effect (high CA > 150掳 and low CAH < 10掳) or petal effect (high CA > 150掳 and high CAH 10掳).