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Expulsion of Unimers from Polystyrene‐ block ‐poly(acrylic acid) Micelles
Author(s) -
Gao Lichao,
Shi Linqi,
Zhang Wangqing,
An Yingli,
Jiang Xiaowei
Publication year - 2006
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200500496
Subject(s) - micelle , acrylic acid , dynamic light scattering , chemistry , polystyrene , copolymer , aqueous solution , polymer chemistry , hydrodynamic radius , chemical engineering , organic chemistry , nanoparticle , polymer , engineering
Summary: The pH response of the micelles of polystyrene‐ block ‐poly(acrylic acid) (PS 200 ‐ b ‐PAA 78 ) in water is studied using a combination of techniques: static light scattering (SLS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). The structure of the micelles in dilute aqueous solution is dependent on pH. At pH values <2.5, the micelles precipitate. At pH values from 2.5 to 3.5, the micelles associate to form micellar clusters. At pH values ranging from 3.5 to 8.0, the micelles are dynamically frozen. At pH > 8.1, some PS 200 ‐ b ‐PAA 78 unimers gradually escape from the micelles and subsequently re‐associate to form smaller micelles.The pH‐responsive behavior of the PS 200 ‐ b ‐PAA 78 micelles in solution.