Preparation Of Super-hydrophobic Surface Based On Inorganic Metal Materials

Super-hydrophobic surface can be applied in various fields for its great property. However, the preparation of super-hydrophobic surface with high mechanical and corrosion-resistant property is still of great difficulty. In the present study, the preparation of super-hydrophobic surface based on inorganic metal materials was carried out after the summary of former work. Aluminum plate and foam nickel were used as substrate, and electro-deposition and hydrothermal method were adopted as preparation method. The influence of surface morphology on super-hydrophocity and corrosion-resistant property were investigated through the change of synthesis condition. The main contents and conclusions are as follows:(1) Electro-deposition method was chosen to prepare Ce/stearic acid super-hydrophobic surface. The FT-IR results reveal that stearic acid has been deposited on the surface of alumilum plate after electro-deposition process; SEM analysis shows that the deposited surfaces possess two different morphologies:the protrude structure with oriental growth and the flake structure; EDS result reveals that the element components of the above two structures differ from each other tremendously; Orthogonal experiments with four factors and three levels were established to investigate the influence of cerium nitrate concentration, stearic acid concentration, electro-deposition voltage and electro-deposition time on the result. To study the relation between prepared surface and WCA, SEM and WCA tests were performed on the prepared samples. The order of the influence of the four factors is as follows: cerium nitrate concentration> electro-deposition voltage> electro-deposition time> stearic acid concentration. The optimal preparation condition is as follows:cerium nitrate concentration is 0.02 mol/L, stearic acid concentration is 0.15 mol/L, electro-deposition voltage is 10 V and electro-deposition time is 40 min. The biggest water contact angel can reach 131°.(2) Super-hydrophobic cerium surfaces were prepared through electro-deposition method. The components, morphology and mechanical property of the surface were investigated. XRD result shows that cerium has been deposited on the surface of the substrates. Three different metal materials were used as substrate to simply investigate the influence of different substrate on super-hydrophocity. It can be concluded from the result that nickel foam possess the best hydrophobicity and its WCA is approximately 140°, while the suppressed possess the worst hydrophocity. These results are highly in accord with the theory of Cassie model. Silica gel and zinc phosphate were adopted as immersion solution to promote the mechanical property of the prepared material. Compared with zinc phosphate, the silica gel can promote the mechanical property more evidently without lowering hydrophobicity.(3) CO3O4/Al composite was prepared by hydrothermal synthesis. The morphology and components of the composite were characterized. It is observed from the XRD results that a-Co(OH)2 has grown on the surface of nickel foam and transformed into CO3O4 after calcination. SEM tests reveal that low concentration of CTAB, long synthesis time or high synthesis temperature is unsuitable for the growth of integrated nano-flake; The nano-flake structure will form when the above factors are properly set. Therefore, much emphasis should be put on the regulation of the experiment condition. Orthogonal experiments with four factors and three levels were established to investigate the influence of cerium nitrate concentration, CTAB concentration, synthesis time and synthesis temperature on the result. PFAS modification was carried out on the as-prepared samples to investigate the influence of the above four factors on the super-hydrophocity. The order of the influence of the four factors is as follows:synthesis temperature> CTAB concentration> cerium nitrate concentration> synthesis time. Ultrasonic treatments were tested on the prepared samples to investigate their mechanical property. The results showed that the mechanical property of the prepared samples should be further improved.(4) Co3O4/nickel foam composite was prepared by hydrothermal synthesis. The morphology and components of the composite were characterized. It is observed from the XRD results that a-Co(OH)2 has grown on the surface of nickel foam and transformed into CO3O4 after calcination. Single factor experiments were carried out to investigate the influence of synthesis time and synthesis temperature on the results. The WCA increases to 144°and 156° when the synthesis time gets longer; Meanwhile, the synthesis temperature also greatly influence the WCA result. PFAS modification was carried out on the as-prepared samples to investigate the influence of the above four factors on the super-hydrophocity. The relation between surface morphology and super-hydrophocity were investigated by WCA tests. Corrosion tests were conducted on the prepared samples. The results showed that the clean foam nickel nickel foam corroded heavily, and the WCA decreased to 33°,67°,58°, respectively. Although PFAS can improve corrosion-resistant property to some degree, the WCA decrease greatly when compared with that before corrosion tests. PFAS modified Co3O4/nickel foam with three different morphologies preserve their superhydrophobicity after corrosion. One can see from the result that the nano-folwer and nano-flake possess much better superhydrophocity and the WCA of them is 152° and 155°, respectively. The above results indicate that loading of Co3O4 play more important role in the hydrophobicity.