| This work has focused on the amorphous carbon that has low surface energy to prepare the superhydrophobic surface. The preparation of the carbon/silica composite films, carbon/silica multilayer films, resorcinol formaldehyde (RF) resin/silica films and aligned silica nanotrees which based on sol-gel method combining with the phase separation and template method, and the investigation of the techniques as well as the relationship between the microstructure and the superhydrophobicity.The preparation of the superhydrophobic carbon/silica composite films were prepared by mixing sol, using sol-gel method which employed the RF resin as the carbon source and tetraethylorthosilicate (TEOS) as the silica precursor. The carbonization process was confirmed by TG/DTA technique, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to make sure the carbon formed from RF resin was amorphous graphite. Atomic force microscope (AFM) was used to characterize and analyzed the influence of adding quantity of silica sol on the surface microstructure, especially the aligned nanopinlike structured carbon/silica composite films. The superhydrophobic carbon/silica composite films agreed with the complex water contact angle theory of Cassie model. The water contact angle was up to 162.5°as the actual contact area consisted by 4.26% of solid surface and 95.74% of air bed. And the aligned nanopinlike structured carbon/silica composite films were a perfect superhydrophobic surface which agreed with the point by point contacting style in Cassie model.The synthesis of superhydrophobic carbon/silica multi-layer films was based on "silica sol /flame deposition carbon" cycles. This technique was simple, enhanced the mechanical intensity of the carbon film synthesized by flame, the multi-layer films had an perfect superhydrophobic property with a water contace angle about 169.7°and a roll-off angel smaller than 5°. The surface and the across-sectional structure of the multi-layer films were characterized by scanning electron microscopy (SEM). The result indicated that the concentric ring structures distributed uniformly on the surface with a linear arrangement. The transmission electron microscopy (TEM)was employed to observe the structure and size of the amorphous carbon and the silica sol particles.The results of the High-resolution electron microscopy (HREM) indicated that the core-shell structure (silica as core and carbon as shell), this resulted in the uniformity of the components and the properties of the films which have the superhydrophobicity and the high mechanical intensity at same time. X-ray photoelectron spectroscopy (XPS) was used to analyze the changes of the surface chemical component before and after heat treatment.The superhydrophobic RF resin/SiO2 films were fabricated by combining of sol-gel method and phase separation. The phase separation was controlled by changing the RF resin concentration in the RF resin/SiO2 films. The micro and nanostructure surface was obtained by heat treatment at high temperature, it also agreed with the complex water contact angle theory of Cassie model.Superhydrophobic aligned silica nanotrees were prepared by combining of the sol-gel method and the template method. The template was formed by controlling the concentration of the organic component (RF resin). The template was burnt out during the heat treatment and the nanotrees were formed at the same time. The results indicated that the concentration of the RF resin, chemical phase modification and the annealing process had influence on the surface structures. The aligned nanotrees structure achieved the point by point contact style on the interface of solid and liquid, which is a perfect superhydrophobic surface structure.The results of the investigation in this thesis indicated that, the techniques and the factors in the process all have direct influence on the surface micro-structures, and the surface micro-structure determined the superhydrophobicity of the films. |
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