View : 12 Download: 0

Block sequence affects thermosensitivity and nano-assembly: PEG-l-PA-dl-PA and PEG-dl-PA-l-PA block copolymers

Title
Block sequence affects thermosensitivity and nano-assembly: PEG-l-PA-dl-PA and PEG-dl-PA-l-PA block copolymers
Authors
Park S.H.Choi B.G.Moon H.J.Cho S.-H.Jeong B.
Ewha Authors
정병문
SCOPUS Author ID
정병문scopus
Issue Date
2011
Journal Title
Soft Matter
ISSN
1744-683XJCR Link
Citation
vol. 7, no. 14, pp. 6515 - 6521
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
We are reporting triblock copolymers of (ethylene glycol) 44-(l-alanine) 9-(dl-alanine) 9 (PEG-l-PA-dl-PA) with α-helical l-PA localized between flexible PEG and dl-PA, and (ethylene glycol) 44-(dl-alanine) 9-(l-alanine) 9 (PEG-dl-PA-l-PA) with gradient flexibility in water. Aqueous solutions of PEG-l-PA-dl-PA underwent only sol-to-gel transition, whereas those of PEG-dl-PA-l-PA underwent sol-to-gel-to-squeezed gel transitions as the temperature increased. The l-PAs of both polymers have an α-helical secondary structure in water at low temperature. However, the α-helical structure of the PEG-dl-PA-l-PA changed into a random coil structure as the temperature increased above 40°C, whereas the PEG-l-PA-dl-PA kept the α-helical secondary structure over the same investigated temperature range of 4°C to 50°C. Cryo-transmission electron microscopy images and dynamic light scattering suggested that the PEG-l-PA-dl-PA develops spherical micelles, whereas the PEG-dl-PA-l-PA develops cylindrical bundles as well as spherical micelles in water. Even though both block copolymers have a similar composition of (ethylene glycol) 44, (l-alanine) 9, and (dl-alanine) 9, they showed significantly different temperature-sensitivities as well as different nano-assemblies in water. This report suggests that the block sequence of a polymer is very important in developing a specific nano-structure as well as in controlling thermosensitivity of the polymer, thus providing useful molecular information in designing a biomaterial. © 2011 The Royal Society of Chemistry.
DOI
10.1039/c1sm05505d
Appears in Collections:
자연과학대학 > 화학·나노과학전공 > Journal papers
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE