| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 98 === This paper describes a novel method to achieve direct growth of highly-oriented Li-Al LDH film on substrates such as glass, Si wafer and carbon cloth in an alkaline Al3+- and Li+-containing aqueous solution. The substrate samples were each hanged, and then immersed in the solution for LDH film formation in ambient atmosphere. The Li-Al LDH film composed of extra high density of Li-Al LDH platelets, each almost perpendicularly standing on substrate surface. The LDH film thickness increased with increasing immersion time and/or with increasing solution temperature. Consequently, the thickness would reach a plateau region during the LDH formation. The time to reach the plateau region depends on the solution temperature. UV-visible transmittance spectra of the Li-Al LDH films on glasses were reported. The LDH film that was fabricated at 5 oC (~1.45 μm in thickness) exhibits good UV shielding ability (only 9.7% UV transparency) and a maxium of 56% transparency in the visible. A similar method can also be employed to develop a Li-Al LDH film covering on both hydrophobic and hydrophilic carbon cloth surface. The fibers of the treated carbon clothes had extra high density of LDH platelets on surface, which leads to the fibers have remarkably large surface area. In spite of the surface modification on the carbon fibers, the treated carbon clothes still retain their original surface properties (e.g., hydrophobicity or hydrophilicity). The study believed that CO2 in the atmosphere dissolved in the alkaline Al3+- and Li+-containing solution to provide CO32- ions for Li-Al LDH formation. Nucleation and growth of each LDH platelets on substrate surface finally resulted in a LDH film.
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