高分子分散液晶摻雜二氧化鈦之型態及光電特性之研究

Electro-Optical Properties and Morphology of Polymer Dispersed Liquid Crystals Doped with Submicron Particles of Titantum Dioxide

本研究探討高分子分散液晶摻雜二氧化鈦對型態學及光電性質之影響，我們將次微米大小等級的二氧化鈦以0.1 wt%及0.5 wt%兩種濃度與高分子分散液晶做摻雜後將均勻的材料灌入於16 μm 的試片中以紫外光聚合的方法製得高分子分散液晶薄膜，經實驗結果發現摻雜二氧化鈦之驅動電壓由40.1 V 下降至33.9 V，可降低約15%，又液晶微滴大小由2.15 μm 增加至2.53 μm，驅動電壓下降之結果與高分子分散液晶中液晶液滴尺寸變化不謀而合，故藉由摻雜低濃度之二氧化鈦可改善日前高分子分散液晶驅動電壓較高之問題。

After establishing the effects of doping submicron particles of titaniumdioxide (SMP-TiO2) on nematic liquid crystals (NLC), we studied theimpact of low-concentration SMP-TiO2 doping on the morphology andelectro-optical properties of polymer dispersed liquid crystals (PDLCs).We made use of the photopolymerization induced phase separation (PIPS)process to obtain 16 μm thick pure PDLC, PDLC + 0.1 wt% TiO2, andPDLC + 0.5 wt% TiO2 PDLC films. Our results indicate that increasingdoping concentrations of SMP-TiO2 decreased the driving voltage of thePDLC by 15%, from 40.1 V to 33.9 V. This result was consistent withmorphology observations of the PDLC, where the LC droplet size wasfound to increase from 2.15 μm to 2.53 μm. This study pinpoints thepossibility of resolving the issue of high driving voltage for PDLCs, bychanging the LC droplet morphology with low doping concentrations ofSMP-TiO2.