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Wenzel’s model

Schone 1. Liquid behaviors on rough substrates, (a) Wenzel s model, a liquid droplet fills the grooves of the tough substrate, (b) Cassie s model, a Uquid droplet suspends on the grooves. [Pg.362]

Surface Tension, Capillarity and Contact Angle, Rgute 8 Effect of surface stnictures on wetting behavior, (a) Wenzel s model where the liquid penetrates between the structures, (b) Cassie-Baxter modet where water does not wet the surface between the structures... [Pg.1954]

According to Wenzel s equation, obviously, high roughness can enhance the hydrophilicity of a native hydrophilic surface. In our study, such porous film is much rougher than relatively flat surface obtained without using template, so this model can explain why our as-synthesized films show superhydrophilicity with a CA about 5°. After modification with a lower surface free energy material, the air can be trapped in such ordered pore array, and hence a composite surface composed of air and pore array is formed. The measurements show that the surface is superhydrophobic with water CA of 154°. In this case, the Cassie equation is applicable. Based on a simplified model, as schematically illustrated in Fig. 6, the relationship... [Pg.313]

Wenzel s equation applies to what is called homogeneous wetting, and it can only be applied to homogeneous, rough surfaces. Surfaces having heterogeneous character can be modeled with the Cassie-Baxter model [43] ... [Pg.148]

We now return to the topic of rough surfaces and examine Wenzel s approach in a more critical light. We shall consider in succession the case of a hydrophilic surface (0 < 90°) and that of a hydrophobic surface (0 > 90°). All this is based on the model of Bico et al. ... [Pg.219]

The Young s equation is the well-known relationship used to describe a sessile drop at equilibrium on top of a solid surface. This relationship has been discussed thermodynamically and microscopically for purely flat surfaces in the literature. To characterize the non-flatness of a surface, one may introduce the Wenzel s roughness r defined as the area of the wall surface devided by the area of its projection onto the horizontal plane. Obviously, r is equal to 1 once the surface is flat. For r>l, it is known that Young s equation has to be modified to take into account the increase of surface. The generalization of Young s relation is the so-called Wenzel s law. In this presentation, we will study this relation within microscopic models. We will in particular show that the roughness may enhance the wetting of the substrate even at the microscopic scale. [Pg.24]

Wenzel,V., Padosch, S.A., Voelckel, W.G., Idris, A.H., Krismer, A.C., Bettsch, A., Wolfensberger, R., and Linder, K.H. Survey of effects of anesthesia protocols on hemodynamic variables in porcine cardiopulmonary resuscitation laboratory models before induction of cardiac arrest. Comp. Med., 50, 644-648, 2000. [Pg.301]

In the Wenzel model, the apparent contact angle 0w is obtained by correcting the Young s contact angle 0 with a roughness correction factor r... [Pg.3144]

Barth M, Younglove T, Scora G, Levine C, Ross M, Wenzel T (2007) Comprehensive Modal Emissions Model (CMEM). version 2.02 User s Guide. UnivCTsity of California. Riverside Center for Environmental Research and Technology... [Pg.310]

In the simplest case, the wettability of a solid surface is commonly evaluated by the contact angle given by Young s equation. Then Wenzel proposed a model describing the contact angle on a rough surface, and Cassie proposed an equation for the surface composed of solid and air. The concepts of these equations are outlined in fig. 7.18 [106]. [Pg.164]


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See also in sourсe #XX -- [ Pg.396 , Pg.396 ]




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