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Effects of Intermicellar Interactions on the Dissociation of Block Copolymer Micelles: SANS and NMR Studies
Author(s) -
Cheng Gang,
Hammouda Boualem,
Perahia Dvora
Publication year - 2014
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.201300597
Subject(s) - micelle , copolymer , decane , chemistry , dissociation (chemistry) , polymer , polystyrene , solvent , polymer chemistry , hydrodynamic radius , neutron scattering , small angle neutron scattering , chemical engineering , chemical physics , organic chemistry , aqueous solution , scattering , physics , optics , engineering
The effects of intermicellar interactions on the dissociation of block copolymer micelles of polystyrene‐ block ‐polyisoprene in a selective solvent, decane, are investigated using small‐angle neutron scattering (SANS) and 1 H NMR spectroscopy. This well‐studied polymer is used as a model system to correlate intermicellar interactions with overall micellar stability. Decane is a preferential solvent for polyisoprene (PI) and drives the association of the polystyrene (PS) blocks, resulting in spherical micelles with a PS core and a Gaussian PI corona. The dissociation of the PS–PI micelles is triggered by increasing temperature, while the intermicellar interactions are controlled by varying the polymer concentration and modulating temperature. With increasing temperature, the cores of the micelles first swell, followed by a breakdown to smaller micelles, with similar shapes, that eventually dissociate into single molecules. Herein, it is shown for the first time that enhancing the intermicellar interaction delays the dissociation process of the micelles.