【作者】 李丽颖；

【导师】 陈铁红；

【作者基本信息】 南开大学 ， 物理化学， 2005， 硕士

【摘要】 双亲性嵌段共聚物由于在选择性溶剂中可以形成纳米尺度的自组装结构,被广泛应用于纳米材料的构造、药物缓释等方面。聚氨基酸是一类低毒、生物相容性好、容易被机体吸收、代谢的生物降解高分子,在医学领域如药物控释、人造皮肤等方面具有广泛的应用。我们通过共聚的方法将亲水性的聚乙二醇链段引入疏水性聚氨基酸链段中,得到双亲性嵌段共聚物,并对其在水溶液中的自组装进行了研究。采用盖布瑞尔伯胺合成法( Gabriel method) ,将聚乙二醇单甲醚(monomethoxy poly ethylene glycol, MPEG)的端羟基转化成端氨基,得到大分子引发剂——端氨基聚乙二醇单甲醚(MPEG-NH2),通过红外光谱、核磁共振等手段对其结构进行了表征。利用三光气和L-苯丙氨酸反应合成了N-羧基-α-苯丙氨酸-环内酸酐(NCA),通过红外光谱测试确定了产物。利用MPEG-NH2引发NCA单体开环聚合,分别合成了不同分子量的聚乙二醇单甲醚-聚L-苯丙氨酸嵌段共聚物。红外光谱、核磁共振、凝胶渗透色谱等测试结果表明,合成产物为分子量分布较单一的两嵌段共聚物。采用透析法制备了嵌段共聚物的溶液自组装聚集结构,并用透射电子显微镜(TEM)研究了其形态。结果显示,合成的嵌段共聚物具有双亲性,在不同的条件下在水溶液中能够自组装形成胶束、复合胶束、囊泡、复合囊泡、纤维、纳米带等复杂结构。更多还原

【Abstract】 Amphiphilic block copolymers are unique building blocks in supramolecular polymer chemistry, both for the generation of highly organized, self-assembled structures and for the energetic and structural control of material interfaces. Poly(amino acid) is a kind of biodegradable materials with low toxicity, excellent biocompatibility, biodegradability and bioabsorbability in vivo. However, their poor hydrophilicity limited their biomedical applications in drug delivery systems and tissue engineering. In this thesis, amphiphilic block copolymers with hydrophilic monomethoxy poly ethylene glycol (MPEG) and polypeptide were synthesized and their self-assembly morphologies in water were observed by TEM.The macromolecule initiator, amine-terminated (MPEG-NH2) was synthesized by Gabriel method, in which the end group of hydroxyl was converted to amino group. The macromolecule initiator was characterized by IR, 1H NMR. The result of these experiments showed that this macromolecule initiator was an effective initiator in ring opening polymerization of N-carboxyanhydrides(NCA).The L-phenylalanine N-carboxyanhydride (b-Phe-NCA) was prepared according to phosgene method (Fuchs-Farthing method), by reacting amino acids with triphosgene. Copolymers with various molecular weights were synthesized by ring opening polymerization of NCA on amino-terminated MPEG. The structure of these copolymers were characterized by means of FTIR、1H NMR and GPC.Self-assembled structures in water of the synthesized diblock copolymers were prepared by the dialysis method. The morphologies of the aggregates were investigated by TEM. The result proved that these amphiphilic diblock copolymers can be self-assembled to micelles, vesicles, rods, fibrilla and nanobelt in water.更多还原