The Biomimetic Design And Fabrication Of Superwetting Materials And Related Properties

Recently,there exist some problems such as icing,corrosion,oil pollution and friction and wear of large mechanical equipment in people's daily life and industrial production.The abovementioned problems are related to the wettability of the material surface by exploring the reason.Indeed,wettability has an important influence on the interaction of the interface.Therefore,the way we have proposed to solve the problem is bionics,which is learned from nature.And we could get a lot of inspiration.Learning the self-cleaning effect of the lotus leaf,its surface is composed of hierarchical micro-and nanostructure,learning the underwater superoleophobic property of shark skin,the surface is composed of regular micro-structure;learning the water collecting characteristics of the desert beetle,the surface is composed of a hydrophobic/hydrophilic structure.These bio-surfaces with special wettability provide many inspirations and ideas for designing and fabricating biomimetic superwetting materials.The enlightenment from nature is that the wetting properties of the surface are closely related to the surface chemical composition and microstructure.The super-wetting interface functional materials can be designed and constructed by combining the multi-dimensional structure and the chemical composition of the surface.Metal organic framework(MOF)is a class of material built by the coordination of metal ions or clusters with organic ligands,yielding three-dimensional porous networks with large pore volumes and high internal surface areas.MOF has become promising crystal in gas storage,catalysis,and liquid phase separation owing to its high specific surface area and porosity.However,many MOF loses their structure and high specific surface area when exposed to water.Therefore,it is significance to endow water-sensitive MOF with hydrophobicity.On the one hand,the superhydrophobic coating could act as a candidate material.However,most methods of constructing coating materials are high-cost and time-consuming,and most of the modifiers are environmentally polluting.In addition,the drawbacks of the coating material in the practical applications are poor mechanical resistance.On the other hand,commercial paper consisting of plant cellulose is easily decomposed and damaged by chemical,physical and thermal treatment.And in the construction process of paper,the process is complicated and pollution to the surrounding environment is easy to be caused.Therefore,based on the biomimetic perspective,the general idea of the research work is to achieve multi-level bionics by bio-inspiring natural structure and regulating surface chemical composition,focusing on the optimization design of superhydrophobicity,superhydrophilicity,underwater superoleophobicity of the material surface.The overall research work can be divided into the following four aspects:(1)In general,Ti-based MOF is water sensitive.In this work,we contribute a facile method to impact superhydrophobicity on water sensitive NH₂-MIL-125(Ti)as demonstrated by chemically coating the exterior of MOF crystals with PDMS.The BET surface area of superhydrophobic MOF is similar to the raw MOF.(2)Inspired from the micro-and nanostructures of lotus leaf,the coating was prepared by only using recyclable eggshell and Zn O to obtain the micro-and nano-hierarchical structure and subsequent modification with stearic acid(STA).Such superhydrophobic coating could withstand UV irradiation and mechanical damage.And the superhydrophobic coating could effectively delay the icing-over process.The completely green fabrication of superhydrophobic coating made by sustainable and low-cost materials could yield a perspective candidate for practical applications in daily life.(3)Inspired from the structure of natural nettle leaf,the superhydrophobic paper containing carboxymethyl cellulose(CMC),hydroxyapatite(HAP)nanowire and Zn O was prepared by a novel and facile method with eco-environmental and modifier-free process.The superhydrophobic property is effectively controlled by different amount of Zn O,which might be effect of surface roughness of the paper.Except for the common performances,such as self-cleaning property,chemical durability and mechanical abrasion durability,the excellent thermal stability and anti-bacterial properties will dramatically extend the practical applications of the paper.In addition,such paper still maintains its superhydrophobicity after flammable oil adsorption-combustion,further validating its excellent fire-resistant property.The combination of superhydrophobicity and flame retardancy can largely enhance the durability of the paper.These characteristics make the multifunctional paper a better candidate than the commercial paper,which may be a breakthrough in paper-making industries.(4)Furthermore,the multifunctional inorganic paper containing hydroxyapatite(HAP),carboxymethyl inorganic paper(CMC)and NH₂-Ui O-66 was prepared by a facile and environment-friendly process for both air and liquid contaminant filtration.In addition,the inorganic paper exhibited underwater superoleophobicity that can be used for the efficient separation of surfactant-stabilized oil-in-water emulsions.The study of superwetting materials has important significance and practical value for human production and life.However,with the deepening of research and the needs of practical applications,the superwetting system is not limited to superhydrophobic surfaces.Among some functionalized surface,superhydrophilic surface(in air),underwater superoleophobic surface,underoil superhydrophobic surface,underoil superhydrophilic surface have attracted much attention due to their applications in self-cleaning and marine anti-fouling which will open new directions for superwetting system.