| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程系碩士班 === 94 === In this study, the functional xSiO2-(1-x)TiO2 optical films have been synthesized onto glassy microslides through spin-coating method by utilized the sols, obtained from sol-gel techniques. Titanium isopropoxide (Ti(O-iC3H7)4) and tetraethylorthosilicate (Si(OC2H5)4) were used as precursors, ethanol as a solvent, hydrochloric acid as a catalyst, and acetylacetone was applied as a chelating agent to complex with titanium alkoxide avoiding the reaction with moisture.
Combining FTIR, DTA/TGA, SEM and XRD techniques, the preparatory variables of gels, the molar ratio of acetylacetone/titanium isopropoxide, the molar ratio of hydrochloric acid/ titanium isopropoxide, the molar ratio of H2O/ tetraethylorthosilicate and gelation temperature, have been studied their effects on the microstructure of SiO2-TiO2 powders and those mechanisms for the evolution of SiO2-TiO2 in the sol-gel process were proposed and discussed. Furthermore, the surface response method (include Box-Behnken design) was applied to deal the preparatory conditions of the sol-synthesized process, and the optimal preparatory conditions have been obtained. It indicates that the gel prepared from the molar ratio of acetylacetone/titanium isopropoxide at 3.9, the molar ratio of hydrochloric acid/ titanium isopropoxide at 0.04 , the molar ratio of H2O/ tetraethylorthosilicate at 5.4 and gelated at 35oC, a high quality SiO2-TiO2 thin film containing less shrinkage and smooth film surface was examined.
And then, xSiO2-(1-x)TiO2 with various molar fractions of Ti were produced. The effects of Ti content on the roughness, microstructure and refractive index of optical films were also revealed. The results indicate that 80 mole % SiO2 - 20 mole % TiO2 thin film exhibits low roughness and high transmittance of the optical properties. As the titanium content increases from 0.2 to 0.8, the refractive index of SiO2-TiO2 thin film raising 1.6 to 1.94.
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