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Synthesis of Amphiphilic ABCBA‐Type Pentablock Copolymer from Consecutive ATRPs and Self‐Assembly in Aqueous Solution
Author(s) -
Zhang Lifen,
Cheng Zhenping,
Zhou Nianchen,
Zhang Rongmei,
Zhu Xiulin
Publication year - 2008
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200850108
Subject(s) - copolymer , micelle , methacrylate , amphiphile , polymer chemistry , aqueous solution , atom transfer radical polymerization , gel permeation chromatography , materials science , methyl methacrylate , chemistry , polymer , organic chemistry
Summary: A novel amphiphilic ABCBA‐type pentablock copolymer with properties that are sensitive to temperature and pH, poly(2‐dimethylaminoethyl methacrylate)‐ block ‐poly(2,2,2‐trifluoroethyl methacrylate)‐ block ‐poly( ε ‐caprolactone)‐ block ‐poly(2,2,2‐ trifluoroethyl methacrylate)‐ block ‐poly(2‐dimethylaminoethyl methacrylate) (PDMAEMA‐ b ‐PTFEMA‐ b ‐PCL‐ b ‐PTFEMA‐ b ‐PDMAEMA), was synthesized via consecutive atom transfer radical polymerizations (ATRPs). The copolymers obtained were characterized by gel permeation chromatography (GPC) and 1 H nuclear magnetic resonance (NMR) spectroscopy, respectively. The aggregation behaviors of the pentablock copolymers in aqueous solution with different pH (pH = 4.0, 7.0 and 8.5) were studied. Transmission electron microscopic images revealed that spherical micelles from self‐assembly of the pentablock copolymer were prevalent in all cases. The mean diameters of these micelles increased from 34, 46, to 119 nm when the pH of the aqueous solution decreased from 8.5, 7.0, to 4.0, respectively.