本論文研究使用膽固醇液晶微球添加可光致同素異構化親手性材料，製作可全光調控微球轉動速度之染料摻雜膽固醇液晶微馬達元件。由於此膽固醇液晶微球之螺旋軸呈現軸對稱性分佈並且於球赤道位置產生缺陷，使得光鉗圓偏振光之角動量可傳遞給膽固醇液晶微球後造成微球轉動現象，藉由膽固醇液晶微球加入的可光致同素異構化親手性材料可經由紫外光照射下使得微球轉動速度變化。
本論文的研究分成兩個部份。在第一部份，我們先探討膽固醇液晶微球受紅光雷射(波長為660 nm、功率為100 mW)之光鉗作用下之轉速與微球螺距及直徑之相依關係；在第二部份，我們再探討，當有摻雜染料之膽固醇液晶微球受一道較弱紫外光(強度為21  82 mW/cm2)照射下，由於正向光致同素異構化反應，膽固醇液晶球內部偶氮親手性分子從棒狀trans態轉變至彎曲狀cis態時局部擾動液晶之秩序性，使得膽固醇液晶微球轉動能力逐漸下降。當紫外光強度提高至109.4mW/cm2時，偶氮親手性分子之光引致同素異構化反應急遽上升，在劇烈擾動膽固醇液晶微球內之螺旋結構之下，膽固醇液晶微球立即停止旋轉。關閉紫外光照射後，當作光鉗作用之長波長紅光雷射可引致反向回復之光同素異構化反應，偶氮親手性材料會從彎曲狀cis態回復至棒狀trans態，使得膽固醇液晶微球之軸對稱結構回復排列，此時膽固醇液晶微球轉動能力回增。因此，藉由照射弱或強紫外光，膽固醇液晶微球在光鉗作用下之轉動可控制行為有潛力應用在可全光調控或可全光開關之微馬達發展上。

This thesis aims to develop an all-optically controllable micromotors based on cholesteric liquid crystal (CLC) microdroplets added with a chiral azobenzenze. The CLC microdroplet shows an axial structure of helical axis with a ring-defect on the equator of the microdroplet such that the circularly polarized red beam of the optical tweezer may transfer its angular momentum to the microdroplet and then induce rotation motion. The irradiations of one UV beam and the beam of the optical tweezer may control reversibly the ability of rotation of the CLC micromotor.
The investigations in the thesis include two parts. In first part, we study the dependence of the rotational ability of the CLC micromotor manipulated by the red beam of the optical tweezer (wavelength: 660 nm, power: 100 mW) on the pitch and the diameter of the CLC microdroplet under the . In second part, a chiral azobenzene is added into the CLC microdroplet for studying the optical controllability of the micromotor. When the chiral azobenzene added CLC micromotor is irradiated by a weak UV beam (intensity: 21  82 mW/cm2), the chiral azobenzene molecules may change from rod-like trans isomers to curve cis ones, which may locally disturb the LC order and thus gradually decay the rotational ability of the CLC micromotor. Once the intensity of the UV irradiation increases up to 109.4mW/cm2, a large number of cis chiral azobenzene may rapidly generate to seriously disturb the microdroplet, which may quickly stop the rotation of the microsphere. The successive irradiation of the red beam of the optical tweezer following the UV irradiation may induce cistrans back isomerization of the chiral azobenzene, which may induce the recovery of the ordered CLC structure in the microdroplet and thus the restoration of the rotational ability of the micromotor. Therefore, the use of the irradiation of weak or strong UV light in controlling the rotational ability of the CLC microsphere under the manipulation of the optical tweezer is applicable to the development of the all-optically tunable or switchable micromotor.

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