Web Release Date: September 28,
Structure and Dynamics in Aqueous Solutions of Amphiphilic Sodium Maleate-Containing Alternating Copolymers
and
Polymers and Complex Fluids, School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK; Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802; Imaging Materials and Media, Research and Development, Eastman Kodak Company, Rochester, New York 14650-2116; Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany; and Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK
Received April 16, 2004
Revised Manuscript Received August 18, 2004
Abstract:
The structure of aqueous solutions of sodium maleate copolymers with comonomers of
variable hydrophobicity are examined using a combination of small-angle neutron scattering, small-angle
X-ray scattering, and rheometry. Semidilute solutions of the copolymers made with mildly hydrophobic
comonomers exhibit scattering and rheology that are typical of flexible polyelectrolytes, with a correlation
length scaling with polymer concentration as c-
with = 1/2 and specific viscosity scaling as c1/2/c3/2
when unentangled/entangled. In contrast, copolymers with more than eight carbons in their hydrocarbon
comonomer form micelles (globules) at low concentrations and molecular weights. For these more
hydrophobic copolymers, the correlation length scales as c- with < 1/3 and the viscosity remains small
until a relatively high concentration at which the globules start to overlap. Once these more hydrophobic
copolymers overlap, the micelles open up and allow intermolecular associations that cause the viscosity
to increase rapidly with concentration, typical of associating polymer solutions.
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