Synthesis and Supramolecular Self-Assembly of Thermosensitive Amphiphilic Star Copolymers Based on a Hyperbranched Polyether Core
作者：Hong, H. Y.; Mai, Y. Y.; Zhou, Y. F.*; Yan, D. Y.*; Chen, Y.
關鍵字：atom transfer radical polymerization (ATRP), hyperbranched, LCST, self-assembly, star copolymers, thermosensitive
論文來源：期刊
具體來源：J. Polym. Sci., Part A: Polym. Chem. 2008, 46, 668. http://onlinelibrary.wiley.com/doi/10.1002/pola.
發表時間：2007年
A novel amphiphilic thermosensitive star copolymer with a hydrophobic
hyperbranched poly (3-ethyl-3-(hydroxymethyl)oxetane) (HBPO) core and
many hydrophilic poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA)
arms was synthesized and used as the precursor for the aqueous solution
self-assembly. All the copolymers directly aggregated into core–shell
unimolecular micelles (around 10 nm) and size-controllable large
multimolecular micelles (around 100 nm) in water at room temperature,
according to pyrene probe fluorescence spectrometry and 1H
NMR, TEM, and DLS measurements. The star copolymers also underwent
sharp, thermosensitive phase transitions at a lower critical solution
temperature (LCST), which were proved to be originated from the
secondary aggregation of the large micelles driven by increasing
hydrophobic interaction due to the dehydration of PDMAEMA shells on
heating. A quantitative variable temperature NMR analysis method was
designed by using potassium hydrogen phthalate as an external standard
and displayed great potential to evaluate the LCST transition at the
molecular level. The drug loading and temperature-dependent release
properties of HBPO-star-PDMAEMA micelles were also investigated
by using indomethacin as a model drug. The indomethacin-loaded micelles
displayed a rapid drug release at a temperature around LCST. © 2007
Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 668–681, 200