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  • 學位論文

含螢光基團之兩性高分子的 合成及其性質研究

Preparation and properties of amphiphilic copolymer containing Rhodamine B fluorophore

指導教授 : 劉英麟

摘要


在本研究中,第一部分以原子轉移自由基聚合法(atom transfer radical polymerization, ATRP)合成兩性嵌段共聚合物poly(poly(ethylene glycol) methacrylate)-b-poly(glycidyl methacrylate) (PPEGMA-b-PGMA)。並將此共聚合物之PGMA鏈段上環氧基團(epoxy)接枝螢光染色劑Rhodamine B (RhB),製備出含有螢光性質的兩性高分子PPEGMA-PGMA-RhB。 由於兩性共聚合物特殊的親疏水性結構,可在有機相(THF)和水相中形成微胞,進而帶動螢光基團進入自組裝結構中。在此觀察並探討自組裝的行為和螢光性質的相關性。在波長365 nm的激發下,高分子出現粉白光的放射。靜置一個月後,溶於THF的PPEGMA-PGMA-RhB高分子,在穿透式電子顯微鏡(TEM)觀察下形成核-殼結構(core-shell)。在此同時,以波長365 nm的紫外光照射,溶液呈現藍光的放射,是受到原本在外圍的RhB自我聚集進入核心內部所致。另外,由於PEGMA具有生物相容性及親水性的性質,未來可以應用在生物染料的細胞標記上及藥物釋放等方面。 實驗第二部分則以自由基聚合法製備末端帶有NH2官能基的聚異丙基丙烯醯胺poly(N-isopropylacrylamide) (PNIPAAm-NH2)。利用PNIPAAm末端上胺基(amino group)的高反應性,可接枝上螢光染色劑RhB,形成具有溫敏性的PNIPAAm-RhB螢光高分子。 由於RhB分子具高親水性,因此PNIPAAm- RhB於水溶液中,增加溫度可以降低RhB分子間的聚集,進而增強高分子的螢光強度。此外,RhB為水溶性染料,接枝在PNIPAAm上可以提高其LCST溫度,未來可以作為溫度誘導調控的感測器。將其溶解於水/氯仿的混合液中,高溫時在波長365 nm的紫外光照射下,發現有藍白光的放射,在穿透式電子顯微鏡(TEM)的觀察下,則自組裝形成奈米環。 此研究中以凝膠滲透儀(GPC)、傅利葉轉換紅外線光譜儀(FTIR)及核磁共振光譜儀(1H NMR)鑑定高分子的分子量和化學結構;以紫外線/可見光光譜儀(UV-vis)和光激螢光光譜儀(PL)量測高分子的光學性質,並由穿透式電子顯微鏡(TEM)觀察高分子在溶液中自組裝的行為。由上述的結果證明,此研究以簡易的方法製備出具白光放射的有機高分子。除了可應用在照明與顯示器光源外,也可藉由高分子獨特的生物相容性,應用於生醫材料及螢光標定方面。

關鍵字

兩性高分子 螢光

並列摘要


Poly(poly(ethylene glycol) methacrylate)-b-poly(glycidyl methacrylate) (PPEGMA-PGMA) diblock copolymer was synthesized through atom transfer radical polymerization (ATRP). Then, PPEGMA-b-PGMA was grafted with Rhodamine B (RhB) fluorophore as a fluorescent label. The amphiphilic copolymers can be spontaneous to form micelles in chloroform/water mixed solutions. Therefore, the blue emission light of micelles results from the aggregation of RhB molecules in nanoscaled domain. Under an excitation at 365 nm, polymer exhibit white light emission in THF aqueous solution. Otherwise, the copolymer has biocompatibility and hydrophilic because of PEGMA chains in the backbone, and so as to be an effective bio-dye for cell labeling. In addition, the amine-terminated poly(N-isopropyl acrylamide) (PNIPAAm-NH2) was prepared by chain transfer radical polymerization. In order to study the characteristic of illumination, the fluorescent dye RhB was grafted with the as-prepared PNIPAAm-NH2 by amidation. Because RhB dye has hydrophilic property in nature, at high temperature, the fluorescence intensity of PNIPAAm-RhB polymer are increased. The RhB- labeled PNIPAAm can assemble nanorings in the mixed solvent of water/chloroform. The fluorescent polymer can emit white light under an excitation at 365 nm. The molecular weight and chemical structures of the prepared polymer were determined by GPC, FTIR and 1H NMR. The emissive properties of fluorescent polymer were characterized by fluorescence spectroscopy. The polymer morphologies were observed by TEM. Finally, this finding provides a convenient approach to the preparation of white light fluorescence polymer.

並列關鍵字

amphiphilic copolymer fluorescence

參考文獻


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