合成與鑑定具發光基團之主鏈型與側鏈型液晶塊式高分子

Abstract

以Suzuki coupling反應合成以fluorene, thiophene, and biphenyl基團所形成具發光性質之共軛硬段，再以不同分子量的poly(ethylene oxide)s (PEO, Mn = 750 and 2000, n = 17 and 44) 作為軟鏈段來形成具發光性質之主鏈型液晶塊式高分子系統。其自我組織之性質會隨著不同的 PEO長度而產生不同的液晶相，當軟鏈段長度逐漸加長，其排列方式由較不規則之向列相 (nematic phases)到層列相 (smectic phases) 最後到規則性高的柱狀相 (colunmar phase)。在光學顯微鏡下的光學紋理圖與X光繞射圖譜（XRD）可以更進一步證明各種不同液晶相。除了液晶性質外，藉由一系列的光學量測以了解不同的軟鏈段（PEO）長度對其共軛硬段發光性質之影響。 除了主鏈型液晶塊是高分子，以各種巨起始劑（macroinitiators，如polystyrene, polyethylene oxide, 與polystyrene-block-polyethylene oxide）經過原子轉移自由基聚合法(atom transfer radical polymerization ,ATRP)聚合出含有不同液晶基(如cyanoterphenyl, biphenyl-4-ylthiophene, biphenyl-4-ylfluorene, 與 4,4’-bis(biphenyl)- fluorene units) 的側鏈型液晶塊式高分子。所合成出之側鏈型液晶塊式高分子主要形成之液晶相為向列相 (nematic phases)與層列A相 (smectic A phases)。其液晶相也經過其光學紋理圖與X光繞射圖譜（XRD）之鑑定。

A novel conjugated aromatic core containing direct-coupled fluorene, thiophene, and biphenyl groups via Suzuki coupling reaction was synthesized. The asymmetrical molecules contain two kinds of poly(ethylene oxide)s (PEO, Mn = 750 and 2000, n = 17 and 44) on one side of the rigid cores. Asymmetrical FOC8PEO17 and FOC16PEO17 contain flexible PEO chains (n = 17) display the smectic phases. However, FOC8PEO44 and FOC16PEO44 consisting of flexible PEO chains (n = 44) exhibit two kinds of columnar phases, Colh and Colr. Besides, alkoxy groups with different lengths (-OC8H17and -OC16H33) on both sides of the rigid cores were used as another flexible chains to form symmetrical molecules. Symmetrical FOC8 and FOC16 exhibit the nematic and smectic mesophases, respectively. Optical textures (POM) and XRD patterns have confirmed the structure of the mesophases and the molecular arrangements. The photophysical characteristics of all luminescent compounds were studied by photoluminescence and UV-visible absorption. In addition, A series of double-layered PLED devices with the configuration of PVK:emitters(100:8 by weight)/TPBI/MgAg/Ag were fabricated and investigated. A series of new mesomorphic block copolymers composed of different macroinitiators, including poly(ethylene oxide), polystyrene, and poly(ethylene oxide)-b-polystyrene, and polymethacrylate with a pendent cyanoterphenyl group, were synthesized through atom transfer radical polymerization (ATRP). The mesomorphic and optical properties of all block copolymers were investigated, and all polymers possess the smectic A phase with mesophasic ranges wider than 100 °C. Moreover, X-ray diffraction (XRD) patterns provided the evidence of the smectic A phase and the corresponding interdigitated packing of all polymers. Besides a pendent cyanoterphenyl group, new liquid crystalline homopolymers and block copolymers composed of methacrylates containing pendent biphenyl-4-ylthiophene and biphenyl-4-ylfluorene units were synthesized. The thermal, mesogenic, and photoluminescence (PL) properties of all polymers were investigated. Polymers containing biphenyl-4-ylthiophene possessed the smectic A phase and polymer composed of biphenyl-4-ylfluorene units exhibited the nematic phase. However, new Luminescent liquid crystalline homopolymers, copolymers, and block copolymers were also polymerized from styrene-macroinitiator and methacrylates with pendent 4,4’-bis(biphenyl)fluorene and biphenyl-4-ylfluorene groups through atom transfer radical polymerization (ATRP). All polymers exhibit the nematic phase. The thermal, mesogenic, and photoluminescent (PL) properties of all polymers were investigated.