1. The model of rough wetting for hydrophobic steel meshes that mimic Asparagus setaceus leaf
- Author
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W. Dong, Shi A. Guan, Lin Geng, Zi Y. Ma, Zai X. Jiang, and Yu D. Huang
- Subjects
Surface (mathematics) ,Materials science ,Surface Properties ,Surface finish ,Models, Biological ,Surface energy ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Plant Leaves ,Biomaterials ,Contact angle ,Colloid and Surface Chemistry ,Biomimetic Materials ,Steel ,Wettability ,Surface roughness ,Surface modification ,Wetting ,Composite material ,Asparagus Plant ,Contact area ,Hydrophobic and Hydrophilic Interactions - Abstract
A comprehensive analytical model is proposed to provide a relationship between the macroscopic roughness and contact angle, which is used to develop macroscopic rough surface and to create biomimetic superhydrophobic surfaces. Using chemical surface modification of steel wires, an artificial hydrophobic surface was prepared. A steel mesh mimicking the Asparagus setaceus leaf was created by lowing the surface energy and enhancing macroscopic surface roughness. Water contact angles as high as 129.0° were achieved on the steel mesh with 200 μm × 200 μm pore size. Bad agreement between the predictions based on the original Cassie–Baxter model and experiments was obtained. The version of the Cassie–Baxter model in current use could not be applied to this problem since the roughness magnitude changes from nano/microscopic to macroscopic. A new model, called macroscopic Cassie–Baxter (MCB) model, is constructed by the introduction of contact area density ( δ ) to original Cassie–Baxter model. It is shown that the measured data is in good agreement with the predicted data based on the MCB model. This model not only for solving macroscopic hydrophobic problems of meshes, but also can be used to solve that of other materials with macroscopic roughness.
- Published
- 2011