摻雜多面體矽氧烷奈米粒子之聚醯亞胺薄膜特性探討及應用

Abstract

本論文研究摻雜多面體矽氧烷(Polyhedral Oligomeric Silsesquioxanes, POSS)奈米粒子於聚醯亞胺(Polyimide, PI)所產生的材料特性變化。經由摻雜奈米粒子POSS改變PI分子間的作用關係，造成POSS/PI的混合材料其內部結構的自由體積增加，使得紅外波段範圍內的吸收強度及聚醯胺酸(polyamic acids, PAA)對PI環化率(thermal imidization)隨摻雜的POSS比例增加而增加；玻璃轉移溫度和裂解溫度隨摻雜的POSS比例增加而降低。 導入PI中的POSS重量百分比增加時，所形成POSS/PI薄膜上的表面能則相對減少，因此可以用來調控液晶分子的預傾角從1o 變化至90o，這種預傾角的調制方法是藉由複雜的合成PI方法所難以達到的。由量測結果可知POSS/PI配向膜的錨定能值在不同的預傾角度均約維持在2.4 × 10-4 J/m2，不受摻雜於PI內的POSS重量百分比影響。最後，我們選用需高預傾角度的不需偏壓光學補償彎曲型液晶盒做為此POSS/PI配向膜的特性測試，，並且由量測結果可知該液晶盒擁有快速的反應時間，反應時間平均值約為3.4 ms。

The characteristics of polyhedral oligomeric silsesquioxanes (POSS) doped polyimide (PI) were studied in this work. It was observed that physical dispersion of POSS in PIs increased absorption in the infrared spectra and imidization of PI and decreased the decomposition temperature and the glass transition temperature with POSS doped concentration in PI due to the increase in free volume of POSS-PI films. The addition of POSS in PIs decreased the surface energy of the PI alignment films and generated a controllable pretilt angle θp in the range 1°<θp＜90°, which is not easily achieved by conventional PI synthesis. The anchoring energy of POSS/PI alignment layer was determined as 2.4 × 10-4 J/m2 regardless of POSS concentration doped in PIs. Finally, one no-bias optically compensated bend (no-bias OCB) cell with a pretilt angle of ~62o was fabricated by using our proposed POSS-PI alignment films. The average response time was determined as ~3.4 ms.