Study On Superhydrophobic Functional Modification And Applications Of Organic And Inorganic Materials

In nature, many plants and insects have superhydrophobicity.In particular, lotus leaves are well known for theirsuperhydrophobic property or so-called ―lotus effect‖. As a type of special wettability, superhydrophobicity is commonly defined as possessing a water contact angle(CA) higher than 150° but a sliding angle(SA) less than 10° under a certain external environment. Then the study of superhydrophobic surface has been received considerable attention for their special properties, such as water-repellency, self-cleaning, anti-corrosion and anti-icing, so the superhydrophobic surfaces are of great interest in various applications. Oil spills and industrial organic pollutants have induced severe water pollution and threatened every species in the ecological system. To deal with oily water, special wettability stimulated materials have been developed over the past decade to separate oil/water mixtures. Basically, synergy between the surface chemical composition and surface topography are commonly known as the key factors to realize the opposite wettability to oils and water.As we all know, most superhydrophobic surface have poor durability,when exposed to a living environment, their micron/submicron binary structures and low surface energy layers could be easily and permanently degraded by cession solution like organic solvent, seawater and acid rain, etc. Hence, facile preparation method using cheap materials to fabricate good stability superhydrophobic materials is still a major challenge. Meanwhile, it is meaningful to study on the application of superhydrophobic surface in oil/water separation areas.In this dissertation,we have successfully prepared three different kinds of superhydrophobic materials according to the traditional route for fabricating superhydrophobic surfaces. The as-prepared superhydrophibic surfaces possess not only good superhydrobicity but also extraordinary stability when exposed to various aggressive medium. Additionally, we have studied on the application of these superhydrophobic materials in oil/water separation areas.(1)Researching the anticorrosion and self-cleaning superhydrophobic wood surface. A simple solution-immersion method for fabrication superhydrophobic wood surface is reported.For a deeper discussion of the effect of adhesion mechanism on the stability of superhydrophobic surface, laurylaldehyde and lauric acid were chosen to modify wood surface. Two kinds of superhydrophobic wood with contact angles of 160°(SW1) and 154°(SW2) were successfully fabricated through a simple solution-immersionmethod. In comparison to SW2, the SW1 which was obtained by chemical bond possesses not only bettersuperhydrophobicity but also more extraordinary stability when exposed to aggressive medium including acidicand basic corrosive solutions, organic solvent, and simulated seawater. Additionally, SW1 shows an excellent environmental adaptability like anticorrosion from simulated acid rain, good water resistance andhighly self-cleaning ability. This method is expected to prolong the lifetime of the woodwork under our living environment. Meanwhile, this method can also apply to cotton textile andfilter paper for oil/water separation. Such research could not only help us to further understand the effect of the adhesion mechanism on the surface stability,but also give us the design principle for the fabrication of a superhydrophobic surface with great strength.(2) Researching the preparation and applications of high stability superhydrophobicmesoporous silica. An efficient method for synthesis of superhydrophobic mesoporous silica nanospheres(SMS1,SMS2) by using tetraethoxysilane(TEOS), γ-aminopropyltriethoxysilane(APTES) and triethoxyvinysilane(VTEO) as precursors. The SMS1 and SMS2 possess extraordinary stability when exposed to aggressive medium including acidic and basic corrosive solutions, organic solvent and the water contact angle is higher than 160° from beginning to end. Additionally, we successfully manufactured superhydrophobic cotton fabric based on the formation of mesoporous silica 1(MS1), and subsequent hydrophobization using lauryl aldehyde, and the sticky epoxy resin was worked as a caking agent byadhering abundant of MS1 to cotton fabric surfaces. Meanwhile, the superhydrophobic cotton fabric with water contact angle of 155° shows outstanding chemicaland secular stability after exposed to different pH solutions and common household liquids, moreover, the as-prepared superhydrophobic cotton fabric exhibited excellent oil/water separation property with separation efficiency of 98.6%.(3)Researching the anticorrosion superhydrophobic nickel foam surface and it applications in oil/water separation areas. Nickel foam with superoleophilic and superhydrophobic surface has been successfully fabricated via a facile solution-immersion method. The hierarchical structure was prepared on the commercial nickel foam surface byimmersion of dopamine which provided roughness to complement the microscal roughness inherent. After being modified by octadecylamine, the as-prepared nickel foamshowed both superoleophilic and superhydrophobic properties simultaneously, and the water contact angle is 155°. The as-prepared nickel foam possesses good stability when exposed to aggressive medium including corrosive solutions with different pH and organic solvent. Meanwhile, this superhydrophobic nickel foam as a facile device could then be applied in oil/water mixture separation, and it has the advantages of high efficiency and flux, which is suitable for many types of organic solvents or oils.