Fabrication And Properties Of Zinc Oxide

Zinc oxide, as a wide bandgap semiconductor material, is a novelmultifunction inorganic material. It has a very wide range of applications inphotoelectric materials, nano-materials, photocatalytic materials and inorganicantibacterial material because of its excellent optical, electrical, wettable andantibacterial properties and other excellent performance. In recent years, zincoxide has been modified to improve its rate of wettability conversion,photocatalytic properties, antibacterial activities and some other properties. It hasalso been applied in the self-cleaning,"optical switch", as well as inorganicantibacterial materials etc, which will deeply influence both the industrial andsocial development.The superhydrophobic surfaces were fabricated based on solid surfacewettability theory through changing the micristructure and the surface freeenergy of the solid surfaces which were the two factors to influence thewettability of solid surface. The controllable wettibity surfaces were obtained,and the wettabilty conversion was improved, which will provide a theoetical andexperimental basis for potential application of ZnO in wettabilty conversionmaterials. And the antibacterial properties and antibacterial mechanism of zincoxide were studied.The main contents of this work are listed in the following:The ZnO nanoparticles were prepared through hydrothermal method underdifferent hydrothermal reaction time. The ZnO hydrophobic films have beenobtained by depositing the ZnO nanoparticals on the substrates followed bymodified with low surface energy material. The ZnO films modified with lowsurface energy material have showed hydrophobicity with contact angle of water131.3°.The ZnO/Ag films and powders were prepared. The ZnO/Agsuperhydrophobic surfaces with micro and nanoscale hierarchical structures havebeen obtained though optimizing Ag concentrations and the experiment parameters, followed by modified with low surface energy material. The ZnO/Agfilm after modified with surface energy material showed greatsuperhydrophobicity with contact angle of water160.5°. The wettabilityconversion of ZnO/Ag film was studied. The result showed the rate of wettabilityconversion of the ZnO superhydrophobic films has been improved throughdoping Ag in ZnO material. And the ZnO/Ag film displayed reversibleconversion of wettability beteew superhydrophobicity and superhydrophilicityunder UV irradiation and dark alternating. The antibacterial activities of ZnO/Agcomposite powders were explored through K-B disk diffusion method. The resultshowed that the antibacterial activities of ZnO/Ag composite powders, againstStaphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonasaeruginosa, were better than ZnO powders.On the base of the fabrication of the ZnO/Ag superhydrophobic surface, theZnO/TiO₂hydrophobic coatings with the contact angle of water159.1°have beenprepared on the stainless steel. The rate of wettability conversion of the ZnOsuperhydrophobic composite films has been improved through doping TiO₂.Theantibacterial activity of the ZnO/TiO₂superhydrophobic surface againstStaphylococcus aureus specifically and the best antibacterial activity with62.5to125μg· mL^-1 against four test bacteria of a certain concentration of TiO₂werefound by minimum inhibitory concentration （MIC）. With reference to thestandard HG/T3794.2005, has laid certain foundation on the development andutilization of inorganic antibacterial agent.