Fabrications And Properties Of Several Superhydrophobic/superamphiphobic Surfaces

There are many superhydrophobic surfaces in nature such as the lotus leaf that can keep itself clean,compound eyes of the mosquito that cannot be wetted in the humid environment,legs of the water strider that can easily walk on the water,butterfly wings that cannot be wetted in the rain and so on.Owing to the surperhydrophobicity,these insects or plants can better survive in the corresponding environment,which arise strong interest of the scientific researchers.The researchers made great efforts to study the surface structure and chemical composition of the natural superhydrophobic surfaces,finding that the natural superhydrophobic surfaces possess micro/nano scaled roughness and low-surface-energy materials,which are the two key factors for the fabrications of biomimetic superhydrophobic surfaces.Based on it,researchers fabricated a large number of artificial surperhydrophobic surfaces via constructing roughness and introducing low-surface-energy materials on the substrates.As an important part in the surface and interface science,superhydrophobic surfaces possess good antifouling,self-cleaning,and anticorrosion performance,and so on.The study of superhydrophobic surfaces is of great value to the fundamental theory research and practical life.The scientists have employed a lot of smart methods to fabricate them.However,just endowing the substrates with superhydrophobicity is not enough to meet the requirement of the real life.For example,when we prepare superhydrophobic surface on the glass or paper substrates,the original appearance was changed which brought serious negative effects to the special substrates.Therefore,it is important to equip the obtained superhydrophobic surface with another new performance.For example,in order to maintain the original appearance of the substrate,it is significant to prepare transparent superhydrophobic coatings.In order to make the substrate not only water-proof but also oil-proof,it is necessary to realize superamphiphobic surfaces.Looking for more smart methods to realize multifunctional surfaces including superwettable surfaces is still a challenge for us.Therefore,in this thesis,three superhydrophobic surfaces with another new performance were prepared via three simple methods respectively and the surface topography,chemical composition and other performance of the samples were studied by us:(1)Using the absorbent cotton as raw material,coloured superhydrophobic paper was prepared by swelling/dissolution of the absorbent cotton cellulose and precipitation of the cellulose followed by adding prepared superhydrophobic stearate powders.The obtained superhydrophobic paper exhibits outer and inner superhydrophobicity and uniform color similar to the color of corresponding stearates.The surface topography and chemical composition of the obtained superhydrophobic paper are studied using SEM,XPS and FTIR,respectively.Taking the yellow superhydrophobic paper as an example,the mechanical stability of the paper was discussed via friction experiments,showing that the prepared paper has good mechanical stability and uniform superhydrophobicity.In addition,the superhydrophobic paper can exhibit great antifouling and self-cleaning performance.(2)The superhydrophobic polydopamine@SiO2 powders were fabricated via a simple one-pot method based on the tetraethoxysilane hydrolysis,modification of the hexamethyldisilazane and using dopamine as an adhesive.The transparent superhydrophobic coatings can be obtained through spraying the dispersions of the powders in ethanol to the substrates.The transmittance of the superhydrophobic coatings was measured using UV-VIS spectrometers-The results indicated the transmittance of prepared superhydrophobic glass was 80%when the powder concentration was 2 g/L.In addition,the self-cleaning and antifouling performance of the obtained superhydrophobic glass were tested.The superhydrophobic sponge sprayed by the dispersion can be used for oil/water separation.(3)The superamphiphobic copper surface was prepared through oxidation process and displacement reaction to construct multilevel roughness structure followed by the modification of low-surface-energy material.The surface topography and chemical composition of the superamphiphobic copper sheet were studied through SEM,EDS,XPS and XRD,respectively.The contact angles of different kinds of liquids on the superamphiphobic surface were measured via contact angle meter and the superamphiphobic copper surface exhibits large contact angles(>150°)to water,oils and ethanol/water mixtures with different mass fraction.The obtained superamphiphobic copper exhibits great water-proof,oil-proof,self-cleaning and anticorrosion performance.The superamphiphobic copper sheet must be applied for crude oil transportation.