Preparation And Superhydrophobic Property Of Nanoscale Rough Structure On Several Metal Surfaces

Nanomaterials with especially functional properties have attracted much attention because of their promising applications in metal surface self-cleaning, anti-oxidation, anti-corrosion, flow drag reduction and micro-fluid transport. Surface wettability of materials is governed by the microstructure, surface morphology and surface chemical composition. The archetype superhydrophobic surface is that of the lotus leaf, which known as the self-cleaning effect, is found to be a result of the hierarchical micro-nano meter structures, as well as the wax layer present on the leaf surface. Thus, the surface wettability can be controlled by the modulation of surface energy and roughness. The present dissertation describes three simple and easy routes to implement super-hydrophobic surface preparation technology, and succeeded in super-hydrophobic surface on stainless steel, copper, iron and other metal matrix.1. The ZnO nanorods can be obtained by using a two-step chemical method, which is combination of mild sol-gel method and low-temperature solution method. Moreover, the ZnO nanorods can be served to improve the surface wettability of stainless steel, iron and copper. The results showed that the metal surfaces modified by ZnO nanorods possess super-hydrophobic properties. Besides, the hydrophobic properties of metal surfaces and the adhesion between nanorods and substrate can be improved through a second modification by organic lauric acid and BBOT. The adhesion between nanorods and substrate, metal resistant to acid corrosion solution and seawater were enhanced.2. Silver super-hydrophobic structures can be obtained by chemical replacement method of silver nitrades reacting with iron and copper substrates. The reaction rate can be adjusted by the addition of complexing agent sodium thiosulfate solution, finally the well morphology and superhydrophobic silver surface was obtained. The experiment results show that the adhesion between silver film and substrate, metal resistant to acid corrosion solution and seawater are all excellent. By a second hydrophobic modification of lauric acid on the silver, the static contact angle can reach 160°, and the adhesion between the drop and silver super-hydrophobic surface is very low. At the same time, the adhesion between silver film and substrate and resistant to acid corrosion solution and seawater have been enhanced.3. Cu(OH)₂ super-hydrophobic structures can be obtained by chemical etching method on the copper substrate. The static contact angle of modified metal surface is close to 160°and the adhesion between water droplets and superhydrophobic surfaces is very low. Meanwhile, the binding force between super-hydrophobic surface and the substrate is strong enough to resist the corrosion of seawater and acid solution. With a second modifing by lauric acid, the super-hydrophobic properties have been further improved, the binding and anti-corrosion capacity also enhanced. We believe that those super-hydrophobic materials have potential applications in the drains and the shipbuilding industry.