Superhydrophobicity and Superhydrophilicity
The above photo is from Internet
Definitions:
Theories:
Wenzel Equation
Applications:
Microfluidic applications in biotechnology:
Flat glass:
Notes:
“The chemical modification of surface forces alone can typically lead to water contact angles of up to 120o by using fluoropolymeric coatings or silane layers, but not more. To reach the extreame values of the contact angle near 180o, a second ingredient has to come into play: surface structure.”
“Wettability is improved by roughness for a hydrophilic surface, but get worse for a hydrophobic one.”
“The ultraphobic route to glass surfaces presents a fundemental problem: the substrate roughness may hinder transparency owing to scatter losses. To avoid this, the critical requirement is that the surface corrugations do not affect the light waves passing throuth them.”
“The biggest problem facing all self-cleaning or contaminant-free surface applications are ageing and decay.”
Reference:
- Blossey, R., ‘Self-cleaning surfaces - Virtual realities’, Nat. Mater. , vol. 2, no. 5, 301-306 (2003).
- Feng, X. . J. Jiang, L., ‘Design and Creation of Superwetting/Antiwetting Surfaces’, Advanced Materials , vol. 18, no. 23, 3063-3078 (2006).
- Wang, S., Song, Y. Jiang, L., ‘Photoresponsive surfaces with controllable wettability’, J. Photochem. Photobiol. C Photochem. Rev. , vol. 8, no. 1, 18-29 (2007).
- Roach, Paul, Shirtcliffe, Neil J. Newton, Michael I., ‘Progess in superhydrophobic surface development’, Soft Matter , vol. 4, no. 2, 224-240 (2008).
Tags: superhydrophilicity, superhydrophobicity, young equation