Search

An artificial superhydrophobic Poly-p-phenylenebenzobisoxazole (PBO) fiber bundles were designed and prepared using chemical surface modification. Water contact angles as high as 166.3° were achieved. The loading capacities and pressure resistances of these PBO fiber bundle boats were characterized. The highest loading weight of our superhydrophobic boats was more than 9.42 g, which was attributed to the air film trapped around the PBO boat surfaces. The depth of the water pressure resistance was about 656.4 mm.

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.

According to the reformed Cassie–Baxter equation, the superhydrophobic phenylenebenzobisoxazole (PBO) fiber bundle boats were fabricated from mimicking the lotus leaf venation using chemical surface modifications and roughness introduction. Water contact angles as high as 152.3° were achieved for PBO fiber bundles. Furthermore, the loading capacities of the superhydrophobic PBO fiber bundle boats were also measured. And the highest loading weight, 8.36 g, was obtained by the boats treated with 2.0 wt.% (heptadecafluoro-1,1,2,2,-tetradecyl)trimethoxysilane (HFTES). The large loading capacities were believed to arise from the air film surrounding the superhydrophobic surfaces of boats. The results of this study presented new applications of artificial hydrophobic surfaces in areas of miniature aquatic devices.

Mimicking the Asparagus setaceus, hydrophobic copper meshes were fabricated with chemical surface modifications. According to the reformed Cassie−Baxter equation, the superhydrophobicity of the copper meshes is explained and predicted. Water contact angles as high as 134.6° were achieved. Good agreement between the predictions and experiments was obtained. Dynamic contact angles are also performed, and the largest contact angle hysteresis is obtained with 1.0 wt % (heptadecafluoro-1,1,2,2,-tetradecyl)trimethoxysilane (HFTES) treated whereas the smallest hysteresis occurs for 8.0 wt % HFTES treated sample. This is explained in terms of sorption of liquid by the solid and penetration of liquid into the polymer film. Furthermore, the loading capacities and the water pressure resistances of the hydrophobic copper meshes were all performed. The highest loading weight, 18.59 g, and the deepest height of pressure resistance, 66.5 mm, were obtained, when the copper mesh was treated with 1.0 wt % HFTES. In additio...

A novel superhydrophobic carbon fiber fabric boat was prepared by combination of macro-scale rough surface and low surface energy material treatment. The loading capacities of the boats, fabricated from the resulting superhydrophobic fabrics, were also performed. The highest loading weight, 14.80 g, was obtained by a fabric boat treated with 12.0 wt.% HFTES. The striking loading capacity of the superhydrophobic boat is attributed to the air film trapped around the fabric surface.