Preparation Of Several Kinds Of Rare-Earth Oxide Micro-nanostructured Superhydrophobic Surfaces And Investigation Of Their Performance

Wetting property is a kind of important intrinsic property for solid surface, and the metal surfaces with good superhydrophobicity have great application potential in various fields for its great characteristic like surface hydrophobicity and self-cleaning ability. And the super-hydrophobic metal surface have already got fruitful application in fields like metal corrosion resistance, microfluidic control system and oil-water separation. Previous research indicates that the wettability of solid surface depends primarily on its chemical composition, and on its surface roughness as well. Therefore, it is possible to artificially control the surface wettability by artificially control of the surface composition and surface roughness. Generally, there are two ideas for fabricating superhydrophobic surfaces, one idea is to construct rough micro-nanostructures on a surface with low surface energy, and the other idea is to modify a rough surface with low surface energy substance. Basis on the above ideas, many methods have been developed to artificially fabricate the superhydrophobic surfaces, such as Sol-gel method, Chemical vapor deposition method, Plasma etching method, electrochemical method and hydrothermal method. In this research, rare-earth oxide micro-nanostructured super-hydrophobic surfaces with various morphology are prepared and investigated by the simple hydrothermal method. Detailed research work are as follows:(1) By a hydrothermal method, cerium oxide micro-nanostructures with various morphology are in-situ synthesized on aluminum substrate. By changing the additives and the hydrothermal temperature, the morphology of the cerium oxide micro-nanostructures could be controlled. After the surface modification with PFAS, these surfaces showed great super-hydrophobicity with the water contact angle up to 159.4°. Plus, a depth exploration has been done to the cerium oxide micro-nanostructure with tufted morphology, the influence of the additives and hydrothermal temperature was investigated, and a possible growing mechanism for this structure was proposed as well.(2) Erbium oxide micro-nanostructures with three kinds of different biomimetic morphology were in-situ fabricated on aluminum substrate by a hydrothermal method. The kinds of additives were relatively fixed, and the surface morphology could be controlled by controlling the amount of additives and the hydrothermal temperature. After surface modification with PFAS, the experimented surfaces could possess great superhydrophobicity with the water contact angle up to 160.2°. In addition, the influence of experimental conditions on the morphology of the sample surface was carefully investigated, and a possible formation mechanism was proposed. Further, the corrosion resistance property of the superhydrophobic surface was tested by immersing them in a 3.5 wt% NaCl solution. After the immersion for 15 days, no macro and micro defects were shown on the sample surfaces, and the water contact angle of it decreased merely, indicating that these superhydrophobic surfaces possessed great durability.(3) Without adding any surfactants, template agent and precipitating agent, micro-nano-structures of lanthanum oxide were in-situ prepared on the aluminum substrate. The influence of the amount of lanthanum nitrate and the hydrothermal temperature om the surface morphology was carefully discussed. After the surface modification with PFAS, these surface with lanthanum oxide micro-nanostructures showed great superhydrophobicity with water contact angle up to 160°. The acid and alkali resistance property of the superhydrophobic surface was tested, and the result showed the it had good acid and alkali resistance property.