Issue 43, 2009
From the journal:

Journal of Materials Chemistry

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

Seung Yong Lee,a   Yuhan Lee,b   Ju Eun Kim,a   Tae Gwan Parkb  and  Cheol-Hee Ahn†*a  

* Corresponding authors

a Research Institute of Advanced Materials (RIAM), Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea
E-mail: chahn@snu.ac.kr
Fax: +82-2-883-8197
Tel: +82-2-880-5791

b Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea

Abstract

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 pKa values of the diamine groups at the distal PEG blocks. 1H-NMR, GPC and dynamic mechanical analysis were employed for the characterization of modified F127 and its gelation behavior.

Graphical abstract: A novel pH-sensitive PEG-PPG-PEG copolymer displaying a closed-loop sol–gel–sol transition

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Article information

DOI
https://doi.org/10.1039/B912540J
Article type
Paper
Submitted
25 Jun 2009
Accepted
04 Sep 2009
First published
25 Sep 2009

J. Mater. Chem., 2009,19, 8198-8201

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

S. Y. Lee, Y. Lee, J. E. Kim, T. G. Park and C. Ahn, J. Mater. Chem., 2009, 19, 8198 DOI: 10.1039/B912540J

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