Polyimide-Silica-Titania Nanohybrids

Titania (Ti) is another promising partner for the polymer in hybrid composites that are useful for photonic applications because of its high refractive index. When Ti02 is obtained by the sol-gel method, however, it is not easy to prepare hybrid composite thin films of Ti with polymers because of the fast hydrolysis reaction and thus the extremely fast gelation of titanium aUcoxide. Therefore, only a few studies have been reported that describe polymer-Ti composites. Instead, attempts to form composites 

The AFM studies have shown that the microsfructure of PI-Si-Ti ternary hybrid composite films is much finer when the content of the Si-Ti mixture (ST) is relatively low or when die ratio of Si to Ti is relatively high. Fluorescence behavior also has been observed to depend on the ratio of Si to Ti in the Si-Ti mixture and on the total amount of the Si-Ti mixture. This result can be interpreted as being due to the formation of different local structural environments as the Ti content increases. When the Ti content is small relative to Si, the emission spectra display several separated peaks that represent each of the chemical structural environments.  

In this chapter, we discussed recent progress made in the preparation of organic-inorganic polymer nanohybrid materials that are based on silica or sUsesquioxane. We focused on the physical and chemical aspects of incorporating such inorganic components into polymer matrices, the interactions between the components, and tiieir relevant properties. 

Among many kinds of polymer-based nanohybrids containing silica- or silsesquioxane-like materials, we highlighted mainly polyimide-based nanohybrids because they are well-known high-performance step-growth polymers that 

The work was supported by the National Research Laboratory Program, MOST, Korea, the Center for Integrated Molecular Systems, and the Brain Korea 21 Project. 

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