Facile Selective And Diverse Fabrication And Characterization Of Superlyophobic Materials

Superlyophobic surfaces are highly promising for their unique characteristics and for wide applications in self-cleaning,antifreezing,anti-fogging,anti-sticking,etc.It is generally regarded that a superlyophobic surface has a water contact angle higher than 150° and a sliding angle less than 10°.Taking inspiration from the antiwetting surfaces in nature,many experimental approaches have been reported to prepare the superlyophobic surfaces.However,some of the fabrication techniques are potentially costly and complicated for practical applications.Thus,a facile,low cost and suitable method to construct superhydrophobic surface is necessary.And this is the main direction in current research.In this paper,the kaolin nanoparticles were used as the raw material,a series of superhydrophobic,superoleophobic-superthydrophilic and superamphiphobic coating was prepared by means of solvent evaporation method.The fabric was choosed as substrate,a superhydrophobic-superoleophilic fabric was prepared by means of sol-gel method.Their characteristic and properties were also measured in detail,respectively.At last,the mechanism and model of superhydrophobicity,superoleophobicity and superamphiphobicity were also studied.(1)Choosing kaolin nanoparticles as raw materials,stearic acid as modifier,a superhydrophobic coating with excellent properties was prepared by solvent evaporation method.The stearic acid was used to modify kaolin particles,the carboxyls at the end of stearic acid molecules combined with the hydroxyl of the kaolin surface by the covalent bonds formed via the esterification reaction,A layer of stearic acid molecule membrane was then formed on the surface of kaolin particles and made these particles possess enough low surface energy.After these modified kaolin particles were closely packed on the substrate,the materials with micro-and nanostructures have been fabricated,and then the good superhydrophobicity has been achieved.The water contact angle of the surface was 152°,and the sliding angle was 3°.(2)A superhydrophobic-superoleophilic surface was prepared by means of solvent evaporation method.The kaolin nanoparticles were used as the raw material,and the perfluorooctanoic acid,triethoxymethylsilane and diethoxydimethylsilane were used as surfactant.perfluorooctanoic acid adopted here for lowering the surface energy due to its high content of-CF3,-CF2-,and the carboxyl.Kaolin particles were modified with perfluorooctanoic acid by esterification reaction to obtain the superoleophobicity.The coating had a contact angle of 151°±1°,and slide angle of 6° for hexadecane.It is worth noting that this as-prepared material has simultaneous superoleophobicity and superhydrophilicity.When this superoleophobic-superhydrophilic material is submerged in water,the superhydrophilicity of the material causes a layer of water molecules on the material surface,and the water film reduces the contact between the oil and the material surface.The material surface still keeps nonwetting to hexadecane with the oil contact angle of about 153°±1°.(3)A superamphiphobic surface was prepared by means of solvent evaporation method on glass substrates.The kaolin nanoparticles were used as the raw material,and the trichloro(1H,1H,2H,2H-perfluorooctyl)silane was used as surfactant.In the process,the hydrolysis and condensation of trichloro(1H,1H,2H,2H-perfluorooctyl)silane took place.The three Si-Cl groups of trichloro(1H,1H,2H,2H-perfluorooctyl)silane are hydrolyzed to Si-OH groups.Then,the fluoroalkyl groups have been attached to the surfaces of kaolin nanoparticles and a three-dimensional network structure formed by the interaction and condensation.After these functionalized kaolin particles have been accumulated on the substrate,the obtained material displays super-repellency toward both oil and water droplets.And the superamphiphobic coating all had a contact angle greater than 150° for water and oil droplets.(4)Choosing fabric as raw materials,the silica nanoparticles functionalized with methyltriethoxy silane and their in situ incorporation onto fabric,which provided the fabric sufficient roughness and flexility to obtain the durability.Then the fabric was superhydrophobization with aluminate coupling agent,a superhydrophobic-superoleophilic fabric was obtained.This research technique is fairly facile to operate,and no special technique or equipment is required.Moreover,the procedure is cost-effective and timesaving and the as-fabricated super-repellent materials are very stable.It's very meaningful to the application of kaolin and fabric and the preparation of super-repellent materials.