中文摘要：

具有生物相容性的两亲性嵌段共聚物在水中易形成胶束，在医学诊断、体内药物缓释及药物靶向输送方面具有广阔的应用前景．利用二嵌段聚合物聚乙二醇-聚乳酸（PEG-PLA）引发甲基丙烯酸羟乙酯的原子转移自由基聚合，制备了两亲性三嵌段聚合物聚乙二醇-聚乳酸-聚甲基丙烯酸羟乙酯（PEG—PLA－PHEMA），利用凝胶渗透色谱（GPC），红外光谱（FT-IR），1HNMR表征了其聚合物组成；然后利用透析法制备了不同分子量的聚合物胶束，动态光散射（DLS）和透射电镜（TEM）结果表明其形貌规整、尺寸均-，而且胶束粒径在PEG和PLA链段长度不变的条件下，随PHEMA链段的变长而增大．PHEMA链上大量羟基的存在为聚合物胶束的功能化改性提供了反应位点，加上本身完全由具良好生物相容性的聚合物制备，使其在可控药物释放方面具有很大的应用潜力．

英文摘要：

Amphiphilic copolymers that can assemble into core-shell micelles in aqueous media have potential application as drug carriers for controlled-release. In this article an amphiphilic triblock copolymer poly（ethylene oxide）-block-poly（lactic acid）-block-poly（2-hydroxyethyl methacrylate） （PEG-b-PLA-b-PHEMA） was synthesized by ring-opening reaction and atom transfer radical polymerization. The polymers were characterized by 1H NMR, FT-IR and gel permeation chromatography. In aqueous solution, PEG-b-PLA-b-PHEMA can self-assemble into micelles. Characterized by DLS and TEM, micelles are found to be spherical with uniform size. Large numbers of hydroxyl groups on the PHEMA chain offer reaction sites for subsequent functional modification, which make it a promising platforms for drug delivery systems.