操控聚胜肽二級結構之超分子組裝於奈米層狀結構

Abstract

本論文利用接合反應製備了接上分子識別能力官能基的多面體矽氧烷(POSS)，並另以開環聚合(ring opening polymerization)高分子自組裝的技術，製備末端Uracil(尿嘧啶)官能基的聚胜肽的材料，探討這兩種具有結構差異性的MD-POSS與U-PBLG混摻後，在氫鍵作用力下探討其特性變化。 利用 FTIR 及1H NMR 光譜來觀察MD-POSS 和 U-PBLG 之間特殊的多重氫鍵作用力，並計算出在d-chloroform溶劑中的結合常數為 114 M-1。以及利用液相圓二色分光光譜儀，與不具有識別官能基的Isobutyl-POSS同樣與U-PBLG混摻對照組未產生紅位移結果相比，證實了Diaminopyridine和尿嘧啶群之間分子間氫鍵作用力的存在。 廣角X光粉末繞射圖中，U-PBLG在混摻入MD-POSS後於固態下出現了較明顯的的布拉格特徵峰，顯示經過混摻後於氫鍵作用力下，促使結構出現結晶的有序排列。最後，由DSC與TEM圖中，在U-PBLG成分較少的混摻比例情況下，氫鍵作用力效應促使系統呈現均相；U-PBLG增加的比例下，因結構差異性效應提昇造成相分離，更觀察到特殊的二級平板(secondary lamella)聚集的形貌。

U-PBLG (uracil functional group tethered to poly(γ-benzyl-L-glutamate)) and MD-POSS (muti-diamidopyridine functionalized POSS) were synthesized via ring opening polymerization(ROP) and click reaction. The molecular recognition of U-PBLG/MD-POSS results in various morphological changes. The association constant (Ka) for the complex, shows chemical shift of the amide proton of diamidopyridine in the complex U-PBLG/ MD-POSS was 114.07 M–1. The incorporation of MD-POSS into U-PBLG complex forms highly stable hydrogen-bonded complexes led to the red shift in CD spectra. The distance between the plane of hexagonally packed PBLG rods corresponding to d spacing of (31/2)q and 2q appeared in some blends to provide a driving force to form self-assemble into a thermodynamic stable of twisted macromolecular structures. U-PBLG/ MD-POSS blends complex that exhibited ordered cholesteric lamellar structures, with the d spacing being controlled by changing the U-PBLG content.