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Multiple sol-gel transitions of PEG-PCL-PEG triblock copolymer aqueous solution

Title
Multiple sol-gel transitions of PEG-PCL-PEG triblock copolymer aqueous solution
Authors
Hwang M.J.Joo M.K.Choi B.G.Park M.H.Hamley I.W.Jeong B.
Ewha Authors
정병문
SCOPUS Author ID
정병문scopus
Issue Date
2010
Journal Title
Macromolecular Rapid Communications
ISSN
1022-1336JCR Link
Citation
vol. 31, no. 23, pp. 2064 - 2069
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
An aqueous solution of a poly(ethylene glycol)-polycaprolactone- poly(ethylene glycol) (PEG-PCL-PEG) with a composition of EG 13CL 23EG 13 undergoes multiple transitions, from sol-to-gel (hard gel)-to-sol-to-gel (soft gel)-to-sol, in the concentration range 20.0â35.0wt.-%. Through dynamic mechanical analysis, UV-vis spectrophotometry, small angle X-ray scattering, differential scanning calorimetry, microcalorimetry and 13C NMR spectroscopy, the mechanism of these transitions was investigated. The hard gel and soft gel are distinguished by the crystalline and amorphous state of the PCL. The extent of PEG dehydration and the molecular motion of each block also played a critical role in the multiple transitions. This paper suggests a new mechanism for these multiple transitions driven by temperature changes. An aqueous solution of EG 13CL 23EG 13 undergoes sol-to-gel (hard gel)-to-sol-to-gel (soft gel)-to-sol multiple transitions, where the hard gel and soft gel are distinguished by crystalline and amorphous state of the PCL. The mechanism of transitions and molecular characteristics in each phase are investigated. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
DOI
10.1002/marc.201000403
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자연과학대학 > 화학·나노과학전공 > Journal papers
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