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首页> 外文期刊>Macromolecular chemistry and physics >Functional poly[(ethylene oxide)-co-(β-benzyl-L-aspartate)] polymeric micelles: block copolymer synthesis and micelles formation
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Functional poly[(ethylene oxide)-co-(β-benzyl-L-aspartate)] polymeric micelles: block copolymer synthesis and micelles formation

机译：功能性聚[（环氧乙烷）-共-（β-苄基-L-天冬氨酸）]聚合物胶束：嵌段共聚物的合成和胶束的形成

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摘要

Well-defined α-methoxy-ω-amino and α-hydroxy-ω-amino poly(ethylene oxides) (PEOs), obtained by chemical modifications of α-hydroxy-ω-amino PEO, were studied for block copolymerization with β-benzyl-L-aspartate-N-carboxy anhydride (BLA-NCA); the block copolymers were obtained via polymerization of BLA-NCA with the primary amino end-groups of the PEOs as initiator in the mixture CHCl_3/N,N-dimethylformamide (DMF)(vol. ratio 10/1). Gel-permeation chromatography (GPC) of both block copolymers showed the presence of BLA oligomers. α-Methoxy PEO/PBLA and α-hydroxy PEO/PBLA block copolymers were submitted to selective precipitation in 2-propanol; this method allowed total elimination of oligomers as shown by GPC of the purified block copolymers. Moreover, for each block copolymer, the number of BLA units determined by ~1H NMR spectroscopy (in CDCl_3) was in good agreement with the number calculated from the ratio BLA-NCA/amino end-groups of PEO. The polymeric micelles having hydroxy functions or methoxy groups on the outer-shell were prepared by dialysis against water of the corresponding solution of the pure block copolymers. These polymeric micelles were characterized by dynamic light scattering (diameter) and by fluorescence spectroscopy (critical micellar concentration, cmc) using pyrene as a fluorescence probe. Both polymeric micelles have a small diameter ( < 50 nm) and a very low cmc ( < 20 mg/L in water).
机译：研究了通过对α-羟基-ω-氨基PEO进行化学修饰而获得的定义明确的α-甲氧基-ω-氨基和α-羟基-ω-氨基聚环氧乙烷（PEO）与β-苄基的嵌段共聚-L-天冬氨酸-N-羧酸酐（BLA-NCA）；嵌段共聚物是通过在混合物CHCl_3 / N，N-二甲基甲酰胺（DMF）（体积比为10/1）中以PEOs的伯氨基端基为引发剂通过BLA-NCA聚合得到的。两种嵌段共聚物的凝胶渗透色谱法（GPC）均显示出BLA低聚物的存在。将α-甲氧基PEO / PBLA和α-羟基PEO / PBLA嵌段共聚物在2-丙醇中进行选择性沉淀；该方法可以完全消除低聚物，如纯化的嵌段共聚物的GPC所示。此外，对于每种嵌段共聚物，通过〜1 H NMR光谱法（在CDCl 3中）测定的BLA单元的数目与由比率BLA-NCA / PEO的氨基端基计算的数目非常一致。外壳上具有羟基官能团或甲氧基的聚合物胶束是通过将纯嵌段共聚物的相应溶液用水透析而制备的。这些聚合物胶束的特征在于动态光散射（直径）和荧光光谱（临界胶束浓度，cmc），使用pyr作为荧光探针。两种聚合物胶束的直径均较小（<50 nm），cmc极低（在水中<20 mg / L）。

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