| Summary: | 博士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 96 === Organic-inorganic hybrid materials have been extensively studied recently since their molecular tailing properties could produce new functionalities. Titania and silsesquinoxaine represent two important nano-building blocks for hybrid materials. However, hybrid optical films based on these two nano-building blocks have not been fully explored yet. The objectives of this thesis are to synthesize hybrid nanocomposites of polymer/titania or silsesquioxane and explore their optical applications, including high refractive index films, antireflective films, and optical waveguides.
Two classes of polymer/nanocrystalline titania hybrids are synthesized and characterized. The methodology and procedures for high refractive index polyimide nanocrystalline-titania (PI-TiO2) hybrid optical materials are described in Chapter 2. A soluble polyimide with carboxylic acid end groups is formulated with titanium n-butoxide to yield the hybrid materials. The titania content could be as high as 90 wt% and thus a relative high refractive index of 1.943 could be obtained. It also demonstrates the application in three-layer anti-reflective coating and the reflectance is less than 0.5 % in the visible range. Besides, photosensitive poly(acrylic acid) – titania (PAA-TiO2) hybrid optical materials are synthesized and described in Chapter 3. Poly(acrylic acid) grafted with half degree of poly(ethylene glycol methacrylate) are formulated with titania modified with 3-methacryloxypropyl trimethoxysilane to yield the resist. Nanocrystalline titania could be generated by further hydrothermal treatment and well dispersed in the polymeric matrices. The hybrid films could be also patterned by a direct lithographic process and have high refractive index. These materials might have the potential applications in antireflection coating devices.
For silsesquioxane-based nanocomposites, photosensitive or porous hybrid materials are synthesized and characterized. In Chapter 4, Propargyl methacrylate - functionalized poly(hydrogen silsesquioxanes) (PHSSQ-PMA) is synthesized by hydrosilylation and then formulated with acrylic monomer mixtures to yield the photosensitive optical hybrid materials. The hybrid materials could be developed to Y-shape channel patterns and have the applications in different optical waveguides. An example of nanoporous poly(methyl silsesquioxane) (Nanoporous PMSSQ) thin films fabricated through thermally sacrificing a new porogen, dimethylamino-functionalized polyhedral oligomeric silsesquioxane is presented in Chapter 5. Nano-size pores are homogeneously dispersed in PMSSQ matrices. Meanwhile, the low refractive index and the low dielectric constant could be obtained. The nanoporous thin films suggest the potential applications in low refractive index films and low-k dielectrics.
The above titania or silsesquioxane based hybrid materials exhibit superior optical characteristics than their parent polymers. Such materials would be of interest in various optical and optoelectronic devices, such as antireflective films and optical waveguides… etc.
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