有機/無機混成高分子與團聯式共聚高分子在液態之超分子結構研究

Abstract

由分子設計過後的高分子，例如團聯式共聚高分子(diblock copolymr)，可以利用許多方法使其自組裝(self-assembly)形成某特殊型態之超分子以及微胞結構，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高分子材料已受到許多的矚目與探討。 本研究首先透過具有反應性官能基的多立面倍半矽氧烷寡聚體(POSS)進行開環聚合反應(ring opening polymerization)合成不同分子量的有機/無機混成星狀(POSS-cored star PCLs)與直線型(mono-POSS-capped-PCLs, mPPCLs)聚己內酯。而沒有混成的聚己內酯本身可以進入環糊精的孔洞內，進行主客化學反應(host–guest chemistry)而形成超分子結構(inclusion compolex)，但因為聚己內酯分子截面積的關係，其只能與□-和 □環糊精但是卻不能與□環糊精產生超分子行為， 我們所合成出來的星狀與直線型的混成高分子亦能像未混成之聚己內酯，與環糊精有相同的行為模式。這些超分子結構經由x-ray繞射，固態以及液態核磁共振光譜，傅利葉轉換紅外線光譜，以及微分掃瞄熱光譜儀鑑定，可以證明我們所合成出之POSS-core PCLs與mPPCLs皆與□-和□環糊精形成超分子結構，並擁有圓柱型態(channel type)之結晶晶型。此晶型與聚己內酯本身的晶型結構不同，意即大部分的聚己內酯皆已進入環糊精的孔洞內使其原本的結晶被破壞。經由液態核磁共振光譜可以算出己內酯單元與環糊精的存在比例，由實驗結果得知，巨大多立面倍半矽氧烷寡聚體(POSS)造成的立體阻礙，使得在靠近其之己內酯單元無法順利進入環糊精之孔洞中。經由上列分析結果，我們提出了環糊精與有機/無機混成星狀(POSS-cored star PCLs)與直線型(mPPCL)聚己內酯所形成之超分子之可能結構。 在高分子相關研究領域中，團聯式共聚高分子微胞是個被廣泛研究的課題。由於團聯式共聚高分子微胞可以因為改變共聚高分子之組成以及共溶濟組成等因素，而形成不同的型態的自組裝特性，因此已受到許多的矚目與探討。在本研究中，我們分別利用開環聚合反應(ring opening polymerization)與nitroxide mediate polymerization (NMP)合成poly(4-vinylpyridine)-block poly(□-caprolacone) (P4VP-b-PCL)半結晶鏈段團聯式共聚高分子。此共聚高分子可以在甲苯/二氯甲烷以及甲醇/二氯甲烷兩種溶劑對(solvent pair)中，依據不同的鏈段比例而自組裝形成各種型態。在甲苯/二氯甲烷溶劑對中，當PCL鏈段越來越短的時候，我們可以依序得到球狀微胞，碗狀以及多層泡囊，多孔以及大型的複合性微胞。在甲醇/二氯甲烷溶劑對中，由於PCL在甲醇中會結晶，因此提供了一項擾動平衡的因素，而當P4VP鏈段越來越短的時候，我們可以依序得到球狀微胞，蟲狀短柱，囊泡，以及囊泡與薄板的共存結構，最後我們可以得到片狀的薄板結構。

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 and supramolecules of polymeric building blocks are attracting increasing attention. We have synthesized a series of the organic/inorganic hybrid star PCLs and mono-POSS-end-capped PCL (mPPCL). These star PCLs and mPPCL can form inclusion complexes (ICs) with □- and □-CD, but not with □-CD. These CD ICs were characterized by XRD, solid state 13C CP/MAS NMR spectroscopy, 1H NMR spectroscopy, FT-IR spectroscopy, DSC, and TGA. Our results suggest that the PCL chains of these star polymers lose their original crystalline properties and were included inside the channels provided by the CDs to form columnar crystalline structures. The stoichiometries (PCL: CD) that we determined by 1H NMR spectroscopy for all of the ICs with □- or □-CD are higher than those of the corresponding CD/linear PCL ICs because of the steric hindrance around the bulky POSS moity, which causes some□of the□□-caprolactone units near the POSS moity to be free from complexation with the CDs. From these analyses, we proposed some possible structures for the CD/star PCL and CD/mPPCL ICs. The micellization of block copolymers have been a topic of intense interest in polymer science. Various morphologies can be tuned basically depend on the block length and cosolvent compositions. Here, semicrystalline diblock copolymers P4VP-b-PCL have been synthesized by the living ROP of CL following by the TEMPO-polymerization of 4-VP. Depending on the relative block length and different solvent composition, these copolymers self-assembled into different supramolecular structures in toluene/DCM solution, including spherical micelles, bow-shaped vesicles, multilayer vesicles, porous spheres and large compound micelles. In methanol/DCM solution system, the crystalline of PCL cores disturb the balance of free energy, thus resulted a series of morphological changes including spherical micelles. worm-like rods, vesicles, coexisted vesicles and lamella, and finally platelet lamella.