标题：Conformation and aggregation behavior of poly(ethylene glycol)-b-poly(lactic acid) amphiphilic copolymer chains in dilute/semidilute THF solutions
作者：Yao, Bingjian; Zhu, Qingzeng; Liu, Hui; Qiao, Liang; Hao, Jingcheng; Qi, Feng
作者机构：[Yao, Bingjian; Zhu, Qingzeng; Liu, Hui; Qiao, Liang; Hao, Jingcheng] Shandong Univ, Sch Chem & Chem Engn, Minist Educ, Key Lab Special Funct Aggregat 更多
通讯作者地址：[Zhu, QZ]Shandong Univ, Sch Chem & Chem Engn, Minist Educ, Key Lab Special Funct Aggregated Mat, Jinan 250100, Peoples R China.
来源：JOURNAL OF APPLIED POLYMER SCIENCE
关键词：biomaterials; diblock copolymer; transmission electron microscopy;; dynamic light scattering; gel permeation chromatography
摘要：The behavior of amphiphilic copolymer chains in a solvent is not the same as that of homopolymers. As an important synthetic biomaterial, poly(ethylene glycol)-b-poly(lactic acid) copolymers are often dissolved in tetrahydrofuran (THF) for study. Few studies have focused on the potential aggregation behavior and compact conformation of the amphiphilic macromolecules in a THF solution. In this study, a series of poly(ethylene glycol)-b-poly(lactic acid) diblock copolymers were synthesized and characterized using fourier-transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and gel permeation chromatography methods. The aggregation behavior of amphiphilic molecular chains in a THF solution was studied using dynamic light scattering and transmission electron microscopy. The results showed that the aggregation size in solutions at a concentration of 2.0 mg/mL is within the range of 50-250 nm. It was further demonstrated that molecular chains exhibit a compact conformation in a dilute THF solution, which leads to a comparatively larger deviation in the characterization of molecular weights using GPC method. Here, a model is proposed to elucidate the dynamic evolution between compact amphiphilic single chains and aggregates. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012