New Polyimide and Poly(acrylate)/Titania HybridOptical Films

Organic-inorganic hybrid materials could combine the unique properties of organic and inorganic components to form new functional materials. Among hybrid materials, titania presents the important nanobuilding block and possess several unique optical properties, such as high refractive index. In this thesis, new hybrid optical films of polyimide or polyacrylate–titania hybrid materials were studied for optical applications. New high refractive index polyimide–titania hybrid materials were synthesized and characterized. A soluble polyimide grafted photosensitive methacrylate was first synthesized from 4,4’-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 3,5-diaminobenzoic acid (DABA), 4-aminobenzoic acid (4ABA), and 2-hydroxyethyl methacrylate. Then, the remaining COOH could undergo an esterification reaction with titanium butoxide and provide organic–inorganic bonding to obtain a homogeneous hybrid solution. Then, it was spin-cast into thin films and cured to obtain the hybrid films. These hybrid films possess a wide range of tunable refractive index (n=1.58-2.03), excellent thermal properties, and good transparency in visible range. Besides, they could be also developed to a Y-shape channel patterns with 50 line width.n the second topic of this thesis, thermal curable polyacrylate–titania hybrid materials were synthesized and characterized. First, precursor solution was prepared from methacrylate modified titania precursors and methacryalte monomer mixture. Then, the precursor solution was spin-cast to thin films and followed by multi-step theraml curing process to obtain the hybrid films. The prepared hybrid films poseess tunable and high refractive index (n=1.50-1.73), good surface uniformity and optical transparency in the visible range.