A novel pH-sensitive PEG-PPG-PEG copolymer displaying a closed-loop sol-gel-sol transition

作者：Lee Seung Yong; Lee Yuhan; Kim Ju Eun; Park Tae Gwan; Ahn Cheol Hee^*

来源：Journal of Materials Chemistry, 2009, 19(43): 8198-8201.

DOI：10.1039/b912540j

A thermogelling PEG-PPG-PEG triblock copolymer, Pluronic F127, was modified with diamines containing different numbers of secondary amino groups in order to produce a novel pH-sensitive gelling material. The degree of end group modification was over 95% without any noticeable multi-block formation. Modified F127 displayed a closed-loop sol-gel-sol transition in 16 wt% PBS solution and the loop was significantly shifted with pH depending on the nature of end-capping diamines. Temperature-and pH-sensitive phase transition was caused by a subtle change in hydrophilicity and hydrophobicity balance derived from the pK(a) values of the diamine groups at the distal PEG blocks. (1)H-NMR, GPC and dynamic mechanical analysis were employed for the characterization of modified F127 and its gelation behavior.

• 出版日期2009