Dependence of Macroscopic Wetting on Nanoscopic Surface Textures

• Published in: Langmuir Vol. 25; no. 22; pp. 12851 - 12854
• Main Authors: Wong, Tak-Sing, Ho, Chih-Ming
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 17.11.2009
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Hydrophobic and Hydrophilic Interactions; Models, Chemical; Nanotechnology - methods; Particle Size; Surface physical chemistry; Surface Properties; Water - chemistry; Wettability; Liquid; Wetting; Theory; Surface tension; Hydrophobicity; Texture; Physicochemical properties; Contact line
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la902430w

The hydrophobicity of a surface can be enhanced by physical textures. However, no existing theories of surface wetting can provide guidance to pinpoint the texture size requirement to achieve super/ultrahydrophobicity. Here, we show that the three-phase contact line tension, τ, is an important link to understand the dependence of macroscopic wetting on physical texture size in an ideal Cassie regime. Specifically, we show that texture size is the dominant parameter in determining surface hydrophobicity when the size approaches a limiting physical length scale, as defined by τ and the surface tension of the liquid.