Biomimetic Synthesis And Performance Research Of Superhydrophobic Wooden Base Surface

Superhydrophobic surfaces with water contact angle (CA) greater than150°and sliding angle (SA) less than10°have attracted considerable interest due to their great importance in fundamental research and potential industrial applications. Generally speaking, superhydrophobic surfaces can be fabricated by creating a rough structure on a hydrophobic material surface or modifying a rough surface with a special low surface energy material. In this thesis, we have reported four kinds of superhydrophobic wooden base surfaces and the main research contents are shown as follows:A layer of lamellar superhydrophobic coating was fabricated on a wooden base surface through a wet chemical deposition process. The superhydrophobic property of the wooden base surface was measured by contact angle (CA) measurements. The microstructure and chemical composition of the superhydrophobic coating were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). An analytical characterization revealed that the microscale roughness of the lamellar particles was uniformly distributed on the wooden base surface and that a zinc stearate monolayer formed on the ZnO coating surface as the result of the reaction between stearic acid and ZnO. This process transformed the wooden base surface from hydrophilic to superhydrophobic:the water contact angle of the surface can reach as high as153°,and the sliding angle was less than5°. The superhydrophobic wooden base surface still maintained the superhydrophobic property when stored under the temperature of60℃for one month or immersed into deionized water for a week.The superhydrophobic wooden base surface was fabricated via a sol-gel process of tetraethoxysilane and a fluorination treatment of1H,1H,2H,2H-perfluoroalkyltriethoxysilanes (POTS) reagent. The crystallization type of silica particles on wood surface was characterized using X-ray diffraction (XRD), the microstructure and chemical composition of the superhydrophobic surface were described by scanning electron microscope (SEM) and energy dispersive spectrometer (EDXA), the bonding force between the silica particles and POTS reagent was analyzed by Fourier transform infrared spectroscopy (FT-IR) and the hydrophobic property of the superhydrophobic wooden base surface was measured by the contact angle (CA) and sliding angle (SA) measurements. An analytical characterization revealed that submicron scale silica spheres stacked uniformly over the wooden base surface, and with the combination of the high surface roughness of silica particles and the low surface free energy film of POTS on wooden base surface, the wooden base surface has turned its wetting property from hydrophilic into superhydrophobic with a maximum water contact angle of161°and sliding angle less than2°.The superhydrophobic spherical-like α-FeOOH coatings was obtained on the wooden base surface in situ by a hydrothermal reaction process and a self-assembly of Octadecyltrichlorosilane (OTS) monolayer. The microstructure, chemical state and composition of the products were observed by scanning electron microscope (SEM), X-rad diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Energy disperse X-ray analysis (EDXA). The hydrophobic property of the treated samples was described by static water contact angle (CA) and sliding water contact angle (SA) measurements. The stability under ambient condition and durability for corrosive liquid of the surperhydrophobic samples were also investigated in this paper. An analytical characterization revealed that the spherical-like a-FeOOH films with micro-nano structure uniformly deposited on the wooden base surface and OTS molecules combined with a-FeOOH films. The water contact angle of the as-prepared samples reached as high as158°and the sliding angle was about4°. The prepared superhydrophobic wooden base surface still maintained the superhydrophobic property when stored under ambient condition for three months or immersed into a sodium hydroxide solution of pH12or a hydrochloric acid solution of pH2for2hours at room temperature.The stable superhydrophobic silica/polystyrene composite coatings with a maximum water contact angle of153°and sliding angle less than5°were fabricated on wood surface by a facile drop-coating method. Scanning electron microscopic (SEM) studies revealed that the composite coatings possess the two dimensional hierarchical structure comprising of micron scale papilla and submicron scale granules. The synergistic effect of the submicron/micron binary structure roughness and low surface energy of PS was responsible for the superhydrophobicity of the coatings. The wettability of the superhydrophobic wooden base surface can be adjusted by controlling the content of modified silica particles in the system. The stability and durability of the products were investigated. It was found that the superhydrophobic wooden base surface still possess superhydrophobic properties when stored under ambient condition for three months or immersed into pure water, some common organic solvents for12hours.