| Inspired by the"Lotus Effect", many people take interests in the research of superhydrophobic surfaces. Superhydrophobic materials imitating lotus leaves have wide applications in many fields, including fog condensation, snow sticking, coatings to resisit water, antifouling clothing, pipeline transport and microliter syringe. In this paper, the related theory of superhydrophobic material and the superhydrophobic phenomenon in nature were mentioned, and the new techniques in prepraration of superhydrophobic surfaces were also concluded. Meanwhile the problems existed in the field of the superhydrophobic research and the the future applications of the material were also discussed. In addition, the classification, preparation and application of emulsion were also referred.There are two ways to acquire superhydrophobic surfaces, one is modifying low surface energy agent on solid surfaces which have micro-nano rough structures; the other is building micro-nano rough structures on the material surfaces which have low surface energy. Between which the method of building micro-nano structure is the key for the preparation of superhydrophobic material. In this article, we started with buiding structure, and obtained superhydrophobic surfaces imitating lotus leaves by building micro-nano structure on different host materials.Colloidal particles in polymer emulsion were used as template, and the superhydrophibic films with beehive-like structure were obtained by the aggregation of the silica particles on the emulsion particles and the dispersion of the silica particles in the water phase. The result showed that the films gained a porous structure after heat treatment. The film changed from superhydrophilic to superhydrophobic after modified by with trimethylchlorosilane (TMCS) in ethanol to form a self-assembled monolayer with low surface energy. The water contact angle (WCA) and the sliding angle (SA) of the film were 157.3°and 4.1°, respectively, and the film had a self-cleaning property. The amount of the monomer and the volume ratio of the silica sol to polystyrene emulsion both had an effect on the roughness of the films; the variation of surface roughness could reflect the change of the wettability of the films: larger surface roughness creates larger WCAs. The weatherability test result of the films showed that the film remained superhydrophobic after being putted indoors for 150 days. Because of the adverse weather conditions, the superhydrophobicity of film which was putted outdoors could only be maintained 40 days.Polyvinyl alcohol (PVA) was added into the silica hydrosol and employed as the phase separation agent to prepare superhydrophobic films. The film obtained superhdrophobicity after modifying with low surface energy agent. The WCA and the SA of the film were 151.2°and 5.2°, respectively, and the film had a self-cleaning property which was similar to the lotus. The result showed that the molecular weight and the mass of PVA both had influence on the morphology of the film, and the morphology of the film could be controlled by changing the the molecular weight and the mass of PVA.PS emulsion and polytetrafluoroethylene (PTFE) were mixed together to prepare superhydrophobic films by a one-step method. The WCA of the film with rough structures was 160.7°, and the water droplet on the film could slide off easily (SA=6.8°). The morphology of the film could be changed by altering the volume ratio of the PS emulsion to PTFE emusion. When the volume ratio reached to 0.5, PS emulsion served as template and the film gained a cobweb-like structure. The weatherability test results of the films showed that the film holded the superhydrophobicity after being putted indoors for 40 days; and the film lost its superhydrophobicity after being putted outdoors for 10 days.The stable water in oil (W/O) emulsion was prepared by using silica hydrosol as water phase, cyclohexane as oil phase and mixed system composed of the sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide(CTAB) as surfactant. The hydrophobic film with flower-like structure was obtained by emulsion method. This micro-nano flower-like structure distributed on the film surface randomly and presented different posture. Because of the less aggregation of the flower-like structure, the WCA of the film was only 121°, which couldn't satisfy the requirement of superhydrophobicity.The research results in this paper indicated that the parameters in the film preparation procedure all had effect on the morphology of the film, no matter what techniques was used. And the change of the microstructure had a direct influence on the surface roughness of the film, but also affected the hydrophobic property of the film. Compared with the organic films, the inorganic films had not only a better weatherability, but also a better adhension to the base.
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