Design principles for superamphiphobic surfaces

• DOI: 10.1039/c2sm27016a
• Publication Date: 2012-10-23T15:14:32Z
• Authors: Hans-Jürgen Butt; Ciro Semprebon; Periklis Papadopo...; Doris Vollmer; Martin Brinkmann; Matteo Ciccotti
• Keywords: Shear force

To predict the properties of superamphiphobic layers we analyzed wetting a square and hexagonal array vertical pillars composed spheres (radius R) partially sintered together. Apparent contact angles above 150° are obtained by pinning non-polar liquid surface at underside top sphere resulting in Fakir or Cassie state. Analytical equations derived for impalement pressure limiting case A0 ≫ R2, where is area regular unit cell containing single pillar. The close investigated numerically. By balancing forces rim drop, calculate apparent receding angle. describe drag reduction flowing slip length. When considering pressure-induced flow through cylindrical capillaries radius rc, significant occurs only thin capillaries. mechanical stability with respect to normal shear analyzed. Nanoscopic silica glass would be able sustain stresses caused capillary forces. For high good should small R (respectively neck diameter) large, whereas large imply low angle hysteresis