本論文中，我們提出了在高分子聚合物薄膜之膽固醇液晶(polymer-dispersed cholesteric liquid crystals，簡稱PDCLCs)中，利用紫外光使PDCLC中的單體聚合成薄膜，此即為光引致聚合反應，而該薄膜將原本在表面所作的配向膜覆蓋且破壞其配向能力，使膽固醇液晶由原本反射的planar結構轉換成散射的focal conic結構；另外，有關液晶材料的相變溫度會由於摻雜手性分子或單體而降低，此因液晶材料內『雜質』濃度增加，而造成的液晶材料之不純度增加，最終導致相變溫度降低，若搭配上述光引致聚合反應，則由於光照區之單體聚合，使該區域單體占總材料之比例下降，即不純度降低，進而使液晶材料之相變溫度上升，該區域之相變溫度與未照光區有所不同。
我們除了探討隨聚合過程改變之相變溫度、聚合物結構、穿透/反射率外，亦利用上述針對高分子聚合物薄膜之膽固醇液晶的特性製作幾項相關的液晶元件，(a) 可溫控顯示不同背景之液晶顯示器，該顯示器亦可使用可撓式(flexible)塑膠基板製成；(b) 利用外加電壓方式顯像之元件：Smart Display；(c) 可溫度切換開關之光閥；(d) 可撓式液晶便條紙。以下簡單分別敘述之；
(a) 可溫控顯示不同背景之液晶顯示器：
利用紫外光經過透射光罩寫入圖像，使聚合區域為散射之focal conic態，且該區域之相變溫度(Tc-I)較未照光區域(Tuc-I)高，故低於Tuc-I時，散射的focal conic圖像顯示於反射的planar結構背景上；而介於Tc-I及Tuc-I之間時，散射的focal conic圖像顯示於穿透的isotropic態背景上；若溫度高於Tc-I時，圖像與背景皆是isotropic態，亦即關閉顯示圖像。此外，該顯示機制亦可運用在可撓式基板上。
(b) 利用外加電壓方式顯像之元件：
若以紫外光寫入圖像時，控溫將樣品固定於planar結構，則照光之後，樣品仍維持在原本未照光反射的planar結構，但基板表面已有聚合物薄膜生成，若施加電壓將液晶拉直，在關閉電壓。所寫入的圖像將會在反射態的背景中顯像。
(c) 可溫度切換開關之光閥：
當PDCLC照射紫外光的時間超過某一特定時間，則表面配向被聚合物薄膜破壞而達成散射態之穿透度最低狀態，若持續照光聚合時，因仍然處於focal conic態，故穿透度不再改變，但單體聚合造成相變溫度上升，直到單體全部聚合為止。該現象可製作相同穿透度，但不同相變溫度的元件，即為一可溫度切換開關之光閥。
(d) 可撓式液晶便條紙：
應用在軟性基板的PDCLC元件在受到適當紫外光照射後可得一散射態之可撓式面板，若施加適當壓力，可如觸控筆般在元件上寫入訊息或圖像，該圖像為反射結構。此外，面板上的訊息可抹除，並可重複使用，該元件稱為可撓式液晶便條紙，亦即所謂的手寫板(tablet)功能。

This thesis demonstrates the pre-polymers in a polymer-dispersed cholesteric liquid crystals (PDCLCs) can be polymerized into a polymer film, which can eliminate the aligning capability of the homogeneous alignment layer. Thereafter, the textures of the cholesteric liquid crystals (CLCs) in UV-cured region can be changed from reflective planar texture to the scattered focal conic one. Additionally, the clearing temperature of the liquid crystals (LCs) can be reduced by doping with chiral dopant or monomers. The cause is the increase of the impurity concentration in LCs. In other words, if the monomers are polymerized, the clearing temperature of LCs in that region should increase due to the decrease of the impurity concentration. Therefore, impurities associated with doping with monomeric and chiral dopants cause the clearing temperature of LCs in cured region to differ from that in uncured region. In addition to the change of the clearing temperature, the structures of the polymer films, the transmittance and the reflectivity are also discussed. Following these effect, several interesting LC devices are demonstrated. Those are (a)thermally switchable and flexible liquid crystal displays (LCDs),(b)electrically/thermally/pressurized addressable LCDs, (c) thermally controllable light valves, and (d) flexible LC notepaper. Brief introductions of above LC devices are given as follows;
(a) Thermally switchable and flexible LCDs：A PDCLC sample is irradiated with a UV light through a photo-mask having the desired patterns, the CLC texture in the UV-cured region is changed from reflective planar texture to the scattered focal conic one. Additionally, the clearing temperature (Tc-I) of the LCs in UV-cured regions is higher than that (Tuc-I) in uncured regions. Therefore, if the cell temperature is lower than (between) Tuc-I (Tuc-I and Tc-I), the scattered patterns are displayed on the reflective (transparent) background. Moreover, the addressed patterns are invisible when the cell temperature increases higher than Tc-I. Such display can be fabricated using flexible substrates as well.
(b) Electrically addressable LCDs：If the PDCLC sample is UV cured at temperature below Tuc-I, the scattered patterns are invisible after blocking the UV light, but becomes visible upon applying a suitable AC voltage by removing the external condition. This application can be used as a security card.
(c) Thermally controllable light valves：As described above, the clearing temperature of PDCLCs can be increased by UV-curing because of the reduction of impurity concentration. Therefore, when the texture of a CLC cell in the UV-cured region are changed to focal conic one, the scattering (transmittance) of light from the sample is maximum (minimum). However, the clearing temperature of PDCLCs can be increased continually with continually irradiating with UV light onto the sample, but the scattering (transmittance) is unchanged. Therefore, thermally controllable light valves with different switching temperature can be achieved.
(d) Flexible LC notepaper：After a flexible PDCLC sample is irradiated with a suitable UV light for a suitable period at isotropic state, the CLC texture in whole sample is changed to scattered focal conic. Reflective patterns can be written onto the scattered PDCLC sample by applying a suitable pressure. Additionally, the patterns can be erased and rewritten. In other words, such a device can be functioned as a tablet.

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