两亲性含糖嵌段共聚物在水中分子聚集形态的转变

两亲性嵌段共聚物在不同的介质中可形成不同形态的有序分子聚集体［１～３］．当其亲水段长度远大于亲油段时，在水中主要形成球形胶束［１］；但当亲水段长度远小于亲油段时，则形成多种形态的分子聚集体，即所谓的“ｃｒｅｗ－ｃｕｔ”聚集体，如球形、柱状、层状、囊泡和管状等［４］．Ｅｉｓｅｎｂｅｒｇ等［４～６］详细研究了聚苯乙烯－ｂ－聚丙烯酸在水中的“ｃｒｅｗ－ｃｕｔ”聚集体，发现聚集体的形态和多种因素有关，如共聚物组成、溶剂、ｐＨ值和金属离子等．以两亲分子形成的囊泡不但可以用来模拟生物膜的结构，而且在药物载体…

Morphological Transition of Molecular Aggregates in Aqueous Solution Formed by Amphiphilic Diblock Copolymers Containing Glycopolymer Segments

Amphiphilic diblock copolymers containing glycopolymer segments, polystyrene block-poly2-(-D-glucopyranosyloxy)ethylacrylate](PS-b-PGEA), were synthesized by atom transfer radical polymerization. The morphologies of the crew-cut aggregates of PS-b-PGEA in water were studied by TEM. It has been found that for one specific diblock copolymer, the morphological transformation from spheres to vesicles was controllable by changing solvents. Spheres, rods and vesicles were found to be the dominant morphologies for PS₅₅-b-PGEA₉when the solvents were DMF, DMF/1,4-doxane and 1,4-dioxane respectively. When same solvent, e.g . 1,4-dioxane, was used, sphere to vesicle transition of crew-cut aggregates was also obtainable by using diblock copolymers of different compositions. The copolymers with a higher hydrophilic segment content tend to form spheres, while those with a lower content yield predominated vesicles.