液晶顯示元件中常添加高分子網絡、奈米顆粒或功能性染料以改善其光電性質，期望能達成低閥值、快速反應以及高對比等良好效能。此篇研究中，為改善膽固醇液晶顯示元件之光電性質，引入不同濃度的聚多巴胺粒子作為添加物。聚多巴胺粒子表面豐富的鄰苯二酚基及胺基提供大量反應位置以供表面改質。經由垂直配向劑 (DMOAP) 作表面處理的聚多巴胺粒子，期望能使液晶分子在周遭形成輻射狀排列，更有效的干擾液晶排列。研究結果顯示，加入改質過後的聚多巴胺粒子能有效提升膽固醇顯示元件的光電效能。其中以添加0.1 wt. % 改質聚多巴胺粒子的膽固醇顯示元件表現最好，相較於原先的膽固醇液晶，具備高對比值 (82.2 %)、低閥值 (2.4 V) 以及快速的反應時間 (7.7 ms)。
為了更進一步提升液晶顯示元件的效能，經DMOAP改質過後的聚多巴胺粒子同樣被加入高分子穩定型膽固醇液晶顯示元件。研究顯示，表面改質的聚多巴胺粒子能夠有效干擾分散在高分子網絡中的液晶分子，並大幅提升元件的對比。添加0.1 wt. % 改質後的聚多巴胺粒子增進高分子穩定型液晶之效能，可達到最高對比 (93.8%) 以及低閥值 (10.4 V) 與快速反應時間 (10.2 ms)。

Liquid crystal displays (LCDs) are often optimized with polymer networks, nanoparticles, or functionalized dyes. High performance with low threshold voltage, fast response and high contrast is expected. In this thesis, to improve the electro-optical performance of cholesteric liquid crystal (CLC) devices, various concentrations of polydopamine (PDA) particle were introduced. Due to the plenty of catechol and amine groups on the particle surface, the synthesized particles provided a lot of active sites for modification. With the surface modification by dimethyloctadecyl-3-(trimethoxysilyl)propyl ammonium chloride (DMOAP), the radial alignment of LC molecules around the surface modified particles was achieved which was expected to disturb the order of the LC arrangement. Based on the results, the modified PDA particles enhanced the performance of CLC devices efficiently. Adding of 0.1 wt. % DMOAP modified polydopamine particles into CLC device shows a higher contrast of 82.2 %, lower threshold voltage of 2.4 V and a fast response time of 7.7 ms.
To further enhance electro-optical properties of LCD, the synthesized DMOAP modified PDA particles were doped into the polymer stabilized cholesteric liquid crystal (PSCLC) devices. The results suggest that the synthesized surface modified PDA particles disturb the aligning of liquid crystals dispersed in polymer networks leads to a great improvement in the contrast of the PSCLC devices. The best performance with high contrast of 93.8 %, low threshold voltage of 10.4 V and a fast response time of 10.2 ms was achieved in the PSCLC device with 0.1 wt. % modified PDA particle.

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