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Changes in nanoassembly of oligocaprolactone end-capped Pluronic F127 and the abnormal hydrophobicity trend of phase transition

Title
Changes in nanoassembly of oligocaprolactone end-capped Pluronic F127 and the abnormal hydrophobicity trend of phase transition
Authors
Jung Y.K.Park M.H.Moon H.J.Shinde U.P.Jeong B.
Ewha Authors
정병문Pramod B. Shinde
SCOPUS Author ID
정병문scopus
Issue Date
2013
Journal Title
Macromolecules
ISSN
0024-9297JCR Link
Citation
vol. 46, no. 10, pp. 4215 - 4222
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Compared with unmodified F127, the concentration range exhibiting sol-gel transition increased for the CL4-F127-CL4 (F-CL4); however, it decreased for the CL12-F127-CL12 (F-CL12), even though both F-CL4 and F-CL12 were hydrophobically modified by the oligocaprolactone (OCL). To understand the abnormal behavior of the OCL end-capped F127, the difference in basic nanoassemblies among the F127, F-CL4, and F-CL12 were investigated at a low concentration of 0.10 wt % as well as at high concentrations exhibiting sol-gel transitions. Dynamic mechanical analysis, 13C NMR spectroscopy, hydrophobic dye solubilization, dynamic light scattering, microcalorimetry, and transmission electron microscopy suggested that F127's undergo a unimer-to-micelle transition, whereas F-CL4's undergo unimer-to-vesicle transition as the temperature increased. On the other hand, F-CL12's with relatively large end-capped OCL formed aggregated micelle structures that undergo temperature-sensitive conformation changes. In addition, as the temperature increased, sol-to-gel-to-syneresis and gel-to-sol-to-gel-to- syneresis transitions were observed for F-CL4 and F-CL12 aqueous solutions, respectively, whereas a sol-to-gel-to-sol transition was observed for Pluronic F127 aqueous solution. The findings suggest that the end-capping of F127 by OCL induces changes in nanoassemblies, which play a key role in different physicochemical properties leading to the abnormal phase behavior. © 2013 American Chemical Society.
DOI
10.1021/ma400268r
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자연과학대학 > 화학·나노과학전공 > Journal papers
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