團聯式共聚物摻合系統的氫鍵作用力及自組裝行為的探討

Abstract

現今大多數的材料都需要經過額外化學的處理或經由電漿(palasma)改質、塗佈(coating)、表面接枝…等方法才可使材料更適合的運用在特殊領域中，然而經由分子設計過後的團聯式共聚高分子(diblock copolymer)，可以利用許多方法使其進行自組裝(self-assembly)並形成某種特殊型態的結構，進而可以將其應用於特殊功能、材料之上，並省去許多繁雜的改質步驟或費時的額外處理。因此運用分子設計和具有自組裝特性的團聯式共聚高分子已受到許多的矚目與探討。 本研究成功地利用陰離子聚合反應與水解反應合成poly(vinylphenol-b-methyl methacrylate)的團聯式共聚高分子；並研究此新型A-B/C互溶的團聯式共聚高分子與一單聚高分子poly(vinylphenol-b-methyl methacrylate)/ poly(vinylpyrrolidone)聚摻後之相行為的變化，透過實驗結果，我們得知當PVP的含量佔整個組成的約20-60%時，整個聚摻系統會產生不互溶的現象(即使此三成分為兩兩互溶的)，並且由於三個成分間不同強弱的氫鍵作用力影響，隨著組成的改變，整個聚摻系統會產生不同的微相分離結構。 我們亦利用開環聚合反應與可控制型活性自由基聚合反應合成了一不互溶且具半結晶性的poly(ε-caprolactone-b-4-pyridine)團聯式共聚高分子並將其與一單聚高分子poly(vinylphenol)進行聚摻，由於三者間氫鍵作用力強弱的差異造成原團聯式共聚高分子自組裝的結構在摻合了不同含量的單聚高分子之後產生了變化，內部的結晶鏈段被排出並產生被侷限的現象，因此形成了不同型態的微結構。除此之外，我們更進一步的導入第四個鏈段poly(styrene)至上述聚摻系統內來做比較，利用其中一端分子量(P4VP)較小的團聯式共聚物分別與poly(vinylphenol)單聚高分子與poly(vinylphenol-b-styrene)團聯式共聚高分子進行聚摻，由於PS鏈段與其他三高分子鏈段的不互溶性有利於整個聚摻系統的微相分離，因此讓我們可以得到更完美的微相分離結構。

Most of today’s materials require additional processing or modification steps in order to obtain the properties that make suitable for particular applications. As an alternative to these raditional fabrication pathways, routes that use the self-assembly of polymeric building blocks are attracting increasing attention. In other words, the self-assembly of block copolymer systems has been extensively studied. In this thesis, we have synthesized series of poly(vinylphenol-b-methyl methacrylate) (PVPh-b-PMMA) diblock copolymers through an anionic polymerization and a subsequent selective hydrolysis reaction and investigated a new type of A-B/C blend formed between poly(vinylphenol-b-methyl methacrylate) and poly(vinylpyrrolidone) which displays unusual phase behavior. DSC results demonstrate that the miscible PVPh-b-PMMA copolymer becomes immiscible up on blending with 20-60 wt % PVP due to two Tgs existed in the blend. Results from TEM images and SAXS analysis indicate that different compositions of PVPh-b-PMMA/PVP blends induce different microphase separation structures due to the significantly stronger hydrogen bond interaction between PVPh and PVP than that between PVPh and PMMA which has confirmed by FT-IR analyses. A series of immiscible crystalline-amorphous diblock copolymers, poly(ε-caprolactone-b-4-vinyl pyridine) (PCL-b-P4VP), were synthesized through combination of sequential ring-opening and controlled living free radical (nitroxide-mediated) polymerizations and then blended with poly(vinyl phenol) (PVPh) homopolymer. Self-assembly morphologies of these immiscible PCL-b-P4VP diblock copolymers changing through competitive hydrogen-bonding interactions with the increase of PVPh contents are presented by TEM images and SAXS analyses. DSC, WAXD, and FT-IR techniques are used to investigate the hydrogen-bonding interactions in this system. Furthermore, we have also employed a PCL-b-P4VP copolymer with a low molecular weight of P4VP to investigate the difference of the miscibility, the phase behavior, and the hydrogen-bonding interaction mechanism compared PCL-b-P4VP/PVPh with PCL-b-P4VP/PVPh-b-PS blend system. All results confirm that the icompatibility of the added PS block with the other three blocks is the main reason which induces the difference of the microphase-separation between PCL-b-P4VP/PVPh and PCL-b-P4VP/PVPh-b-PS blend system.