本研究在室溫下採用溶膠-凝膠法於非質子溶劑(DMAc和DMF)中合成二氧化鈦奈米粒子(約5 nm)；且合成的二氧化鈦溶膠可長期存放(30天)。將可溶性聚亞醯胺與二氧化鈦溶膠依適當比例混合後，藉由旋轉塗佈及多段烘烤(至300 oC)程序製備高折射率聚亞醯胺-二氧化鈦混成薄膜。由FE-SEM可觀察到混成薄膜相當平坦，且二氧化鈦以奈米尺度均勻分布在混成薄膜中，可以避免散射的問題。藉由調控二氧化鈦的含量，在633 nm的折射率可由1.63提升至2.16，顯示具備應用於抗反射塗料及光波導的潛力。 In this study, TiO2 sols with very small particle sizes (~5 nm) were synthesized in an aprotic solvent, N,N-dimethylacetamide (DMAc) and N,N- dimethylformamide (DMF), via sol-gel reaction at room temperature. The TiO2 sol showed long-term storage stability (30 days) and can provide operating control for the preparation of high–refractive–index polyimide-TiO2 hybrid thin films. By means of spin coating and multistep baking (up to 300 oC), the hybrid thin films were prepared from the solutions composed of soluble polyimide and TiO2 sol. The FE-SEM images showed a smooth and uniform morphology of the hybrid thin films. TiO2 domains were in the nanometer range, thus avoiding the light scattering. The refractive indices at 633 nm of the prepared hybrid thin films increase from 1.63 to 2.16 with increasing TiO2 content, which suggested the potential application to anti-reflective coatings and optical waveguides.
