The symmetric triblock copolymer Pluronic P85 with EO(25)PO(40)EO(25) has been studied by small-angle neutron scattering (SANS) at 50 and 60 degreesC at concentrations of 0.25-10 wt.% in D(2)O. The data are analyzed by a model based on Monte Carlo simulations. The micelles are modeled as having a spherical core of poly(propylene oxide) (PPO) with some water surrounded by a corona of the poly(ethylene oxide) (PEO) block. The latter are non-interacting and obey Gaussian statistics, but are expelled from the core region. The analysis shows that the micelles are fairly concentration and temperature independent at the conditions studied. The micelles are slightly polydisperse in the aggregation number and have aggregation numbers in the range 40 - 50. The core contains about 40% water and has a radius of about 40 Angstrom. The corona extends out to about 80-100 Angstrom and has a fairly low volume fraction of polymer, typically less than 10%. (C) 2002 Elsevier Science B.V. All rights reserved.
|Journal||Colloids and Surfaces A: Physicochemical and Engineering Aspects|
|Publication status||Published - 2003|