| Inspired by “lotus effects” and “rose effects”, superhydrophobic surfaces have aroused considerable attentions in recent decade. Those surfaces that own special wettabilities(such as superhydrophobic, superamphiphobic/superoleophobic surfaces) have significant applications in daily life and industrial areas. Both wettability and adhesion are important properties of solid surfaces. In general, the two properties of the surface are determined by surface composition and surface structure. Therefore, the wettability and adhesion of the solid surface can be controlled through regulating the surface composition and morphology. Moreover, due to the complex and versatile outdoor conditions, superhydrophobic surface that only repel water drops cannot fulfill the requirements of industrial and real life. Thus,superamphiphobic/superoleophobic surfaces that repel both water and oil greatly widen the applications of superhydrophobic surfaces. Up to now, although there are more and more skilled methods have been developed to fabricate artificial superhydrophobic or superamphiphobic surfaces, many exigent problems are still unsolved. On one hand, many preparation methods suffer the problems such as expensive materials or equipments, multiple and complex fabrication steps, bad repeatability, and unable to fabricate large-area superhydrophobic surfaces etc. On the other hand, in regard of the stability, most of superhydrophobic surfaces are weak and sensitive to severe environmental conditions and mechanical damage. The above mentioned problems greatly restrict the applications and productivity of superhydrophobic surfaces. Another most important area is that many related studies about superhydrophobic surfaces do not involve the evaluation and research of superhydrophobic stability, in other words, their ability to resist harsh conditions. However,since the stability is extremely important for applications in daily life and industrial area,preparing superhydrophobic or superoleophobic surfaces with robust stability are the primary purpose of researchers. How to solve the weak chemical stability and mechanical durability of most of superhydrophobic or superoleophobic surfaces is very urgent. In conclusion, it is very necessary and significant to optimally select the inexpensive materials and develop convenient, highly efficient, good repeatable, and large-area industrially applied techniques to fabricate superhydrophobic surfaces with fascinating stability. We use many kinds of techniques to build micro/nano structures combining the chemicals to adjust surface free energy on diverse metal and polymer substrates. Not only realizing the regulation of the surface wettability and adhesion, but also achieving a series of chemically stable and mechanically durable superhydrophobic and superoleophobic surfaces. Specially, we mainlyevaluate and characterize the stability of the as-prepared superhydrophobic or superamphiphobic surfaces in detail. It is believed that these results provide meaningful guide for further practical applications. The main work and results are shown as follows:1. Superhydrophobic alumina surface containing hierarchical structure was obtained by using an effective and one-step anodic technique without surface modification. By only controlling the reaction parameters, we obtained two kinds of superhydrophobic alumina surfaces with diverse morphologies. The research results indicated that these two surfaces result in huge difference in water adhesion. The surface with low adhesion presented a water contact angle(WCA) of 157°, and a very low sliding angle(SA) of 1°. On the contrary, the surface with high adhesion obtained a WCA of 154°, and the water did not fall down even when the surface was upside down. The sticky superhydrophobic surface was demonstrated to sustain the inverted water up to 15 μL. The as-prepared surfaces were proved to present good mechanical performance. Moreover, the superhydrophobic surfaces could also withstand ice water, boiling water, high temperature, and oil contamination.2. A highly efficient anodized method was used to prepare large-area chemically stable and mechanically durable superhydrophobic alumina surfaces. In order to confirm the best preparation parameters to fabricate rough hierarchical morphology on the surfaces, the effects of the anodized parameters including current density, electrochemical anodization time, and electrolyte temperature on surface topography and surface wettability were studied systematically. These parameters determine the surface architectures that influence the hydrophobicity. The hierarchical structure when combined with low surface energy conferred the surface excellent water-repellency property. We modified the as-prepared surfaces by using [1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane](PDES) and stearic acid(STA)materials. The chemical stability and mechanical durability of the superhydrophobic surfaces were evaluated and studied by a variety of methods. The obtained results indicated that the PDES-modified superhydrophobic surfaces presented more outstanding stability including chemical stability and mechanical durability toward numerous harsh conditions and also showed superior corrosion resistance.3. Three kinds of superhydrophobic macroporous polymethylmethacrylate(PMMA)surfaces with controllable adhesion through template wetting method were prepared. The template used in this work was the hierarchical alumina membrane(HAM), which was fabricated by one-step anodization method. It was demonstrated that the resultant PMMA surfaces replicated the macroporous structures of the HAM template successfully. By adjusting the wetting temperature, we obtained three PMMA surfaces with diversemorphologies. With the subsequent modification, we found that the three samples all achieved superhydrophobicity, especially they presented huge morphology-dependent adhesion differences. The slippery surface with shallow bowl-shape structure achieved a WCA of 158°and a low SA of 3°. While the sticky surface with deep honey comb structure presented very high water adhesion and achieved a WCA of 152°. The sticky surface supported the inverted water up to 10 μL. Moreover, the as-prepared PMMA samples showed stable superhydrophobicity over a wide pH range, organic solvents immersion, and long-term time period.4. The combination of acid etching and boiling water immersion method was applied to fabricate superamphiphobic aluminum surfaces. The microsteps and nanoplatelets structure were built on the surface. The resultant surfaces were demonstrated to be able to repel oil drops with very low surface tension(such as hexadecane or dodecane). We investigated the effects of the individual microstructure, the individual nanostructure, and the dual structure containing micro/nano structure on surface wettability. The results indicated that only the hybrid structure with micro/nano structure realized superoleophobicity. The chemical stability and mechanical durability of the resultant superamphiphobic surface were evaluated and tested by many kinds of methods in detail. The results showed that the surface achieved superior stability, which withstood many kinds of chemical and physical damages.5. A hierarchical structure consisted of triangular prism arrays and nanoplatelets was successfully achieved on aluminum surfaces, through a one-step hot ammonia etching method.The hierarchical structure when combined with fluorosilane realized superamphiphobicity,which showed repellency to water and oil droplets with surface tension ranged of 25.3-72.1m N m-1. The effects of reaction time and ammonia concentration on surface wettability and adhesion were investigated. We evaluated and characterized the chemical stability and corrosion resistance of superamphiphobic surfaces by various methods. |
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