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Thermo‐ and pH‐Responsive Micelles of Poly(acrylic acid)‐ block ‐Poly( N , N ‐diethylacrylamide)
Author(s) -
André Xavier,
Zhang Mingfu,
Müller Axel H. E.
Publication year - 2005
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200400510
Subject(s) - acrylic acid , micelle , copolymer , aqueous solution , polymer chemistry , acrylate , polymerization , materials science , dynamic light scattering , hydrolysis , polymer , chemistry , organic chemistry , nanoparticle , nanotechnology , composite material
Summary: The bis‐hydrophilic block copolymer, poly(acrylic acid) 45 ‐ block ‐poly( N , N ‐diethylacrylamide) 360 , was obtained after hydrolysis of poly( tert ‐butyl acrylate) 45 ‐ block ‐poly( N , N ‐diethylacrylamide) 360 , synthesized by sequential anionic polymerization of tert ‐butyl acrylate ( t BA) and N , N ‐diethylacrylamide (DEAAm) in the presence of Et 3 Al. The polymer is stimuli‐sensitive with respect to both pH and temperature in aqueous solution, reversibly forming spherical crew‐cut micelles with PDEAAm‐core (〈 R h 〉 z = 21.5 nm) under alkaline conditions for T > 35 °C as well as inverse star‐like micelles with an expanded PAA‐core (〈 R h 〉 z = 43.8 nm) under acidic conditions for T < 35 °C, as indicated by dynamic light scattering.Modes of micelle formation for poly(acrylic acid) 45 ‐ block ‐poly( N , N ‐diethylacrylamide) 360 in aqueous solution depending on the pH and temperature.