期刊
MACROMOLECULES
卷 41, 期 17, 页码 6493-6499出版社
AMER CHEMICAL SOC
DOI: 10.1021/ma7026484
关键词
-
资金
- NSF of China [50533010, 20574013, 20774020]
- Chinese Ministry of Science and Technology [973 Project 2005CB522700]
- Chinese Ministry of Education [305004]
- Science and Technology Developing Foundation of Shanghai [07JC14005, 074319117]
- Shanghai Education Committee [Project B 112]
Recently, the addition of poly(ethylene glycol) (PEG) homopolymers was found to significantly lower the sol-gel transition temperature T-gel of the aqueous system of a block copolymer composed of poly(lactic acid-co-glycolic acid) (PLGA) and PEG, different from the normal phenomenon of a T-gel increase for Pluronic hydrogels of block copolymers of PEG and poly(propylene glycol) (PPG). While such an effect is useful for applications of PLGA-PEG-PLGA physical hydrogels as an injectable biomaterial, it is puzzling why the addition of a hydrophilic homopolymer probably enhances the hydrophobic-association-induced physical gelation of ail amphiphilic block copolymer. A series of PEG homopolymers with different molecular weights and concentrations were examined in the aqueous systems of PEG/PLGA block copolymers with three compositions in the present paper. An immiscibility mechanism was put forward by us to account for the earlier spontaneous thermogelling under the assumption of the structure of a randomly percolated micelle network. Meanwhile, the late physical gelling of Pluronics in the presence of PEG homopolymers was interpreted by an order-interfering mechanism. We further found that the immiscibility mechanism might also work for Pluronics upon addition of ethylene glycol and oligo(ethylene glycol).
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据