團聯式共聚高分子其自組裝與氫鍵作用力之研究

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 copolymr)，可以利用許多方法使其自組裝(self-assembly)形成某特殊型態結構，而可應用於特殊功能、材料上之，可省去許多繁雜的改質步驟或費時的額外處理的功夫。因此運用分子設計，而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。 本研究首先分別利用原子轉移自由基聚合反應(atom transfer radical polymerization , ATRP)與縮合反應合成poly(phenylquinoline)- block - poly(methyl methacrylate) (PPQ -b-PMMA) 硬-軟鏈段團聯式共聚高分子；之後，將合成出的硬段-軟段段團聯式共聚高分子溶於適當的溶劑中，在具有水氣及風速一定的環境中製備出高規則蜂窩狀、六角柱的多孔性薄膜，並以偏光顯微鏡(OM)及掃描式電子顯微鏡(SEM)觀察此高分子薄膜。此外，並探討此共聚高分子在不同條件下的型態學與孔洞大小、壁厚的趨勢，結果已可成功的控制此高規則多孔性高分子薄膜的孔洞大小。 在高分子相關研究領域中，高分子聚摻一直是個被廣泛研究的課題，由於高分子摻混時，整個系統會產生很低的熵(entropy)值，使的絕大部分的摻合系統有著很差的相溶性。透過引入高分子間的特殊作用力，會使得高分子摻合系統相溶性顯著的提升，其中，又以氫鍵作用力被應用的最廣泛。 在具有氫鍵作用力的高分子摻合系統中，有各種的理論去描述系統中的作用力行為及相溶性相圖，其中，以Painter-Coleman association model (PCAM)最能準確的闡述高分子氫鍵摻合系統。因此，在本研究中，我們合成出軟段-軟段團聯式共聚高分子，探討由Painter及Coleman等人所提出的分子內屏幕效應(intramolecular screening effect)，所導致不同序列分佈的高分子，摻合時產生的不同氫鍵作用情形。接著再將此團聯式共聚高分子摻混另一種具有不同氫鍵受體(acceptor)的高分子，進而探討不同序列分佈對三相氫鍵混摻系統所造成的不同相溶情形。此外，我們也探討在三相氫鍵混摻系統中，三個皆具有氫鍵予體(donor)的高分子，摻混時所產生的特殊完全互溶型態。

Most of today’s materials require additional processing or modification steps in order to obtain the properties that make them suitable for a particular application. As an alternative to these traditional fabrication pathways, routes that use the self-asseembly of polymeric building blocks are attracting increasing attention. We have synthesized rod-coil diblock PPQ-b-PMMA copolymers by using the versatile atom-transfer radical polymerization method and have characterized them by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). A regularly porous, honeycomb-structured film was prepared from the dichloromethane solution of the diblock copolymers under a flow of moist air. The diameters of the spherical pores can be controlled in the range from 0.8 to 3 □m by modifying both the rod-coil copolymers’ relative molecular weights and the casting conditions. The wall thickness of the film is varied linearly with the relative molecular mass (Mr). The miscibility and specific interaction in polymer blends have been a topic of intense interest in polymer science. The miscibility of an immiscible blend was enhanced by introducing one component which can form hydrogen bonded with another component. It is the one of the major achievements during last twenty years in polymer blend. This type of interaction has been widely described in terms of Painter & Coleman association model due to exactly prediction in most systems. A series of poly(vinylphenol-co-methyl methacrylate) (PVPh-co-PMMA) block and random copolymers were prepared through anionic and free radical polymerizations, respectively, of 4-tertbutoxystyrene and methyl methacrylate and subsequent selective hydrolysis of the 4-tert-butoxystyrene protective groups. Analysis of infrared spectra suggests that the random copolymer possesses a higher fraction of hydrogen-bonded carbonyl groups and a larger interassociation equilibrium constant relative to those of a block copolymer containing similar vinylphenol content because of the different sequence distribution that may arise from the so-called intramolecular screening effect. Furthermore, the ternary polymer blend of PVPh, PMMA, and PEO with different sequence distribution was performed to study the phase behavior. The miscibility and hydrogen bonding behavior of ternary hydrogen bonded blend of phenolic/phenoxy/PVPh was also investigated. According to the DSC analysis, every composition of the ternary blend shows single glass transition temperature (Tg), indicting that this ternary hydrogen bonded blend is totally miscible in the amorphous phase.