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Title: Molecular modeling of micelle formation and solubilization in block copolymer micelles. 2. Lattice theory for monomers with internal degrees of freedom

A self-consistent mean-field lattice theory of the micellization and solubilization properties of poly(ethylene oxide)-poly(propylene oxide) block copolymers is described. The polymer segments are allowed to assume both polar and nonpolar conformations (corresponding to the gauche and trans rotations of the C-C and C-O bonds), which permits the dependence of the segment-segment interactions on temperature and composition to be accounted for in a physically realistic manner. The phase diagrams of poly(ethylene oxide) and poly(propylene oxide) in water, both of which exhibit lower critical solution temperatures, can be reproduced semiquantitatively. The predictions of the theory compare favorably with published light scattering results on the aggregation behavior of block copolymers and with the authors experimental results for the solubilization of naphthalene in these micelles as a function of polymer composition and molecular weight. The dependence of the micelle-water partition coefficient on polymer composition is not simply related to the proportion of the hydrophobic constituent but depends on the detailed micelle structure. The strong effect of the molecular weight and PPO content of the polymer on the amount of naphthalene solubilized observed experimentally was interpreted in terms of the model results.
Authors:
;  [1] ;  [2]
  1. (Massachusetts Institute of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering)
  2. (Wageningen Agricultural Univ., Wageningen (Netherlands))
Publication Date:
OSTI Identifier:
5847797
DOE Contract Number:
FG02-92ER14262
Resource Type:
Journal Article
Resource Relation:
Journal Name: Macromolecules; (United States); Journal Volume: 26:19
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COPOLYMERS; CHEMICAL COMPOSITION; SOLUBILITY; AQUEOUS SOLUTIONS; MATHEMATICAL MODELS; MICELLAR SYSTEMS; PHASE DIAGRAMS; DIAGRAMS; DISPERSIONS; MIXTURES; ORGANIC COMPOUNDS; ORGANIC POLYMERS; POLYMERS; SOLUTIONS 400201* -- Chemical & Physicochemical Properties