| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 87 === Organic-inorganic hybrid materials have the potential to become a new class of electronic and optical materials. In this study, PMMA-silica and PMMA-titania hybrid thin films were prepared by the in-situ sol-gel process combined with spin coating and multi-step baking. The investigated acrylic monomers were MMA and 3-(trimethoxysilyl)propyl methacrylate (MSMA). The alkoxide monomers for the preparation of the silicate segment were TEOS, methyltriethoxysilane (MTES), phenyltriethoxysilane (PTES), and titanium (IV) n-butoxide. The effects of the molecular structure and composition of the inorganic segment on the properties of the hybrid materials are presented in this thesis.
In the PMMA-silica hybrid materials, the formation of the organic and inorganic segments with curing temperature was observed from the FTIR spectra. The prepared hybrid materials show good thermal stability and no phase separation. The AFM study suggests that the prepared hybrid thin films have excellent planarization. The refractive indices of the prepared hybrid thin films in the wavelength range of 190~900 nm can be controlled by the side group on the Si atom as well as by the content of the inorganic moiety. The order of the refractive index for the prepared hybrid thin films is PMMA-PTES > PMMA-TEOS > PMMA-DEDMS > PMMA-MTES. The refractive index can be tuned from 1.456 to 1.491 by decreasing the MTES content from 33% to 0%. The extinction coefficients of the studied films were almost zero in the wavelength range of 190~900 nm, which indicates very high optical transparence.
In the case of the PMMA-titania hybrid materials, the polymer structures were also well characterized by the FTIR spectra. The DSC study suggests a good dispersion of the PMMA segment in the titania network. The AFM study suggests that the prepared hybrid thin films have superior planarization than the parent titania thin film. The refractive indices of the prepared hybrid thin films can be tuned from 1.491 to 1.574 when the titania content increases from 0% to 35%. The red shift of the absorption maximum of the prepared hybrid thin films can be correlated with the titania content. The prepared hybrid films show very high optical transparence in the visible region.
In conclusions, the synthesis and characterization of the PMMA-silica and PMMA-titania hybrid materials were studied. The prepared hybrid materials have good thermal stability and no phase separation between the organic and inorganic segments. The optical properties can be tuned from their molecular structures and compositions. The AFM study suggests excellent planarization of the prepared hybrid thin films. Hence, the prepared hybrid thin films can be potentially used as optical thin films.
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