Hydrophobic properties of a wavy rough substrate |
| |
Authors: | Email author" target="_blank">G?CarboneEmail author L?Mangialardi |
| |
Institution: | (1) DIMeG-Politecnico di Bari, V. le Japigia 182, 70126 Bari, Italy and CEMeC-Politecnico di Bari, Via Re David 200, 70125 Bari, Italy |
| |
Abstract: | The wetting/non-wetting properties of a liquid drop in contact with a
chemically hydrophobic rough surface (thermodynamic contact angle
e>/2) are studied for the case of an extremely idealized rough profile:
the liquid drop is considered to lie on a simple sinusoidal profile. Depending
on surface geometry and pressure values, it is found that the Cassie and
Wenzel states can coexist. But if the amplitude h of the substrate is
sufficiently large the only possible stable state is the Cassie one, whereas
if h is below a certain critical value hcr a transition to the Wenzel
state occurs. Since in many potential applications of such super-hydrophobic
surfaces, liquid drops often collide with the substrate (e.g. vehicle
windscreens), in the paper the critical drop pressure pW is calculated at
which the Cassie state is no longer stable and the liquid jumps into full
contact with the substrate (Wenzel state). By analyzing the asymptotic
behavior of the systems in the limiting case of a large substrate corrugation,
a simple criterion is also proposed to calculate the minimum height asperity h necessary to prevent the Wenzel state from being formed, to preserve the
super-hydrophobic properties of the substrate, and, hence, to design a robust
super-hydrophobic surface. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|