含超分子作用力之吡啶基側鏈共軛高分子在化學感測、液晶及高分子發光二極體元件之應用

Abstract

本論文研究方向為探討一系列包含吡啶基側鏈共軛高分子，且利用超分子作用力作為自組裝之橋樑，並發展在化學感測、液晶及高分子發光二極體元件之應用。 第一個部份，一系列發光質子受體包含三各共軛環單體，包括一個末端吡啶基和二個側邊取代之甲氧基，是利用Horner-Wadsworth-Emmons (HWE) 和Sonogashira 偶合反應。然後，在以自由基聚合反應，依不同莫爾比和具有傳電洞能力的咔唑共聚。這些質子受體之共聚物和不同代數具有傳電子能力的噁二唑樹枝狀結構，利用氫鍵自組裝去形成超分子之側鏈共聚物。當引進咔唑基團在質子受體共聚物中，是有效的增加玻璃轉移溫度和有較小分子鏈的作用力，在這些發光質子受體之間，且相似的效應也發生在氫鍵樹枝狀錯合物中。另外，氫鍵樹枝狀錯合物螢光放光可以調控 61 nm 的紅位移，且激發咔唑基團可以獲得較強的螢光強度比激發質子受體。電化學方面，引進噁二唑樹枝狀結構在氫鍵樹枝狀錯合物裡，可以獲得較低的最低未占分子軌道的能階和一個好的電子注入性質。質子受體高分子和它的氫鍵樹枝狀錯合物，在電致發光發光放光範圍為464到519 nm，從藍光到綠光。元件方面，氫鍵樹枝狀錯合物顯示一個 519 nm放光，驅動電壓為 6.5 V，一個最大發光 408 cd/m2 在 18 V 和發光效率 0.39 cd/A 在 100 mA/cm2。 第二部份，一系列側鏈型氫鍵液晶共聚高分子網路，包含不同共聚比之發光的質子受體和質子予體，是被成功的合成且利用自由基聚合方式。氫鍵共聚高分子網路擁有較高的玻璃轉移溫度比它們個別的均聚物。氫鍵共聚物和均聚物兩者都表現層列 A 液晶相。氫鍵共聚高分子網路隨著質子予體含量增加，澄清溫度也隨之增加且有利於穩定層列 A 液晶相。另外，氫鍵共聚高分子網路螢光放光可以調控 39 nm 的紅位移比照它的均聚物時，且在電致發光元件和螢光放光的光色可以被調控，從496-500 nm 到531-537 nm 為藍綠到綠光。 最後一部份，開發發光質子受體包含三各共軛環單體，包括一個末端吡啶基和二個側邊取代之甲氧基及二各雙鍵之共軛三環結構，是利用Wittig and Pd-catalyzed Heck 偶合反應和聚合方式為自由基聚合。均聚物表現一個玻璃轉移溫度為 60 °C 和 融點為 150 °C。在醋酸溶液中，螢光放光最大紅位移可以從460 到 605 nm。這均聚物具有高的感測和選擇性，對於鎳離子比其他過渡金屬離子，這是歸因於它具有較強的鍵結且焠熄常數為 5.65 × 106 M-1。另外，當加入 PMDTA 到高分子和銅離子的錯合物，螢光的 ON-OFF-ON 切換行為可被發現，這未來利用在化學感測可以回收利用的價值。

First, a novel light-emitting hydrogen-bonded acceptor containing three conjugated aromatic rings, including one pyridyl terminus and two lateral methoxyl groups, was successfully synthesized via Horner-Wadsworth-Emmons (HWE) olefination and Sonogashira coupling reaction. Moreover, different molar ratios of light-emitting H-acceptor monomer and hole-transporting monomer bearing a carbazole unit were copolymerized through free radical polymerization to obtain light emitting and hole-transporting H-acceptor copolymers. H-acceptor copolymers were complexed with different generations of dendritic H-donors bearing 1,3,4-oxadiazole (OXD) dendrons and terminal benzoic acids via H-bonded self-assembly to form supramolecular side-chain copolymers. In contrast to H-acceptor homopolymer, H-acceptor copolymers incorporated with carbazole moieties effectively enhance the glass transition temperatures (Tgs) and minimize the interchain interations of the light-emitting H-acceptor units, and similar effects occur in their H-bonded dendritic complexes. In addition, red shifts of photoluminescence (PL) emissions in H-bonded dendritic complexes can be tuned up to 61 nm. Furthermore, H-bonded dendritic complexes excited OXD absorption can create a stronger fluorescence than that excited at acceptor absorption. The OXD dendritic wedges in H-bonded dendritic complexes can lower the LUMO energy levels and provide a better electron injection property. H-acceptor polymer and its H-bonded dendritic complexes showed electroluminescence (EL) emissions in the range of 464-519 nm from blue to green. In addition, a PLED device containing H-bonded dendritic complex showed an EL emission of 519 nm under a turn-on voltage of 6.5 V, with a maximum luminance of 408 cd/m2 at 18 V and a luminance efficiency of 0.39 cd/A at 100 mA/cm2, respectively. Second, a series of H-bonded side-chain mesogenic copolymer networks containing different molar ratios of light-emitting proton acceptor and proton donor were synthesized via free radical polymerization. The H-bonded copolymer networks have higher glass transition temperatures (Tgs) than the individual hompolymers. Both H-bonded copolymer and homopolymer complex networks show mesomorphic behavior with the smectic A phase. The isotropization temperatures (Tis) and SA phase stabilities of the H-bonded copolymer networks increase as the molar ratios of H-donor unit increase. Furthermore, the red-shifts of PL emissions in H-bonded copolymer and homopolymer complex networks can be tuned up to 39 nm in contrast to H-acceptor homopolymer. The electroluminescence (EL) and photoluminescence (PL) results of H-acceptor homopolymer and its fully H-bonded cross-linking copolymer show emission colors varying from c.a. 496-500 nm (greenish-blue) to 531-537 nm (green), respectively. Finally, a novel light-emitting receptor containing three conjugated aromatic rings, including one pyridyl terminus and two lateral methoxyl groups (on the middle ring), was successfully synthesized via Wittig and Pd-catalyzed Heck coupling reactions. Homopolymer shows a Tg of 60 °C and Ti up to 150 °C. In CH3COOH solution, homopolymer exhibits a pH-tunable photoluminescence with emission maximum varies from 460 to 605 nm. Homopolymer exhibits an extraordinary sensory selectivity for Ni2+ over other transition metal ions as a result of the stronger binding ability of the Ni2+ onto Homopolymer than other transition metals ions. Stern-Volmer constant for the Ni2+ ion sensing was determined through concentration dependent studies as 5.65 × 106 M-1. In addition, the ON-OFF-ON fluorescent switch behavior upon the addition of PMDTA to the polymer-Cu2+ complexes demonstrates a superior reusability of this chemosensor which is important for the practical use.