合成立體規則性聚2-乙烯基吡啶及其雙嵌段共聚物探討自組裝行為之研究

Structurally well-defined isotactic Poly(2-vinylpyridine)s：Syntheses and Self-Assembly Studies

游婷伊(TING-YI YU)

指導教授 ： 蔡敬誠

國立中正大學/工學院/化學工程學系/碩士(2016年)

摘要

具有立體規則性的高分子在物理性質上有許多特別之處，相同的高分子在不同立體規則性之下所表現出來的物理及化學性質皆有所差異。本研究針對同位性聚2-乙烯基吡啶(isotactic poly-2-vinylpyridine，iP2VP)作探討，因先前的研究中發現同位性聚2-乙烯基吡啶(iP2VP)在摻雜酸性掌性誘導混摻物(chiral dopant) 使其自組裝形成類似生物體的螺旋性結構後進行圓極化雙色光譜儀(CD)之測定效果最佳。因此特別針對2VP進行合成，並將iP2VP高分子進行一系列末端官能化反應，合成雙嵌段共聚物(block-copolymer)以達研究目的，希望可以進一步達到開發新穎之仿生材料之目的。
　　為了檢視在溶液狀態下藉由與掌性混摻物作用以形成四級螺旋結構之可能性等相關自組裝行為之研究，我們將合成一系列具立體規則度的iP2VP嵌段共聚高分子，合成的方式可藉由利用末端帶溴酯基的iP2VP巨起始劑及苯乙烯進行atom transfer radical polymerization(ATRP) 合成iP2VP-b-PS。末端官能化反應步驟如下所示：末端帶雙鍵(allyl end group)的iP2VP聚合物由溴丙烯終止iP2VP高分子的陰離子活性聚合反應而產生；此一末端丙烯基(allyl)官能基則可再經由硼氫化-氧化反應將末端官能基轉化為氫氧基。最後在將末端氫氧基進行酯化反應生成帶溴酯基的iP2VP聚合物；上述之合成方法不僅能有效的控制P2VP高分子的立體規則度，還能幫助雙嵌段間的連接以合成具立體規則度的雙嵌段共聚物，此具立體規則度的雙嵌段共聚物可經自組裝產生有序的奈米結構。更有趣的是，經由加入掌性混摻物至自組裝型態為柱狀之iP2VP-b-PS雙嵌段共聚高分子，則會形成特殊的四級螺旋結構，並可用穿透式電子顯微鏡檢測。

關鍵字

立體規則性 ； 掌性 ； 自組裝

並列摘要

Polymers with tacticity have many special physical and chemical properties, and have found important industrial applications. In this report we focus on the syntheses and self-assembly studies of isotactic poly-2-vinylpyridine-based block copolymer (iP2VP-based block copolymer) as our previous studies have demonstrated that the combination of iP2VP with various chiral dopants can lead to the formation of unusual aggregated helical structure in solution as revealed by ICD experiments.
In order to investigate the possibility of forming helical conformation in solid state block copolymer of iP2VP-block-PS is the target material of my research. Accordingly, a serious of iP2VP-based stereoregular block copolymers, isotactic poly(2-vinylpyridine)-b-polystyrene (iP2VP-b-PS), were prepared by atom transfer radical polymerization (ATRP) of an α-bromoester-terminated iP2VP macroinitiator with styrene. The α-bromoester-terminated iP2VP was prepared from the esterification of hydroxyl-capped iP2VP. The hydroxyl-capped iP2VP was prepared from hydroboration of allyl-capped iP2VP. The allyl-capped iP2VP was generated by using the allylbromide to quench the living anionic chain end of iP2VP. The method offers effective control over the stereoregularity of poly(2-vinylpyridine) and facilitates linking between blocks to provide stereoregular BCPs, which are capable of generating well-ordered nanostructures resulting from the self-assembly of stereoregular BCPs. Interestingly, the addition of chiral dopants into the iP2VP-b-PS diblock copolymer, which has the volume fraction for self-assembly in a cylindrical morphology, resulted in the formation of a unique quaternary-ordered helical structure as shown by TEM analyses.

並列關鍵字

stereoregular ； chirality ； self-assembly

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