Eur. Phys. J. E 6, 15-24 (2001)
Orientation-dependent depletion interaction in rodlike colloid-polymer mixtures
A. Matsuyama and T. KatoDepartment of Chemistry for Materials, Faculty of Engineering, Mie University, Tsu Mie 514-8507, Japan matuyama@chem.mie-u.ac.jp
(Received 23 May 2001 and Received in final form 18 July 2001)
Abstract
Depletion interaction in a suspension of rodlike colloids with added
non-adsorbing polymer coils is theoretically studied. We calculate an
overlap volume of depletion zone between two rodlike colloids, based
on the second virial approximation. We examine nematic-isotropic phase
transition (NIT) and two-phase coexistence between an isotropic and a
nematic phase at low polymer concentrations. We find that the
depletion interaction is dependent on the orientational order
parameter of rodlike colloids and leads to a decrease in the NIT
concentration on the addition of polymer. The coexistence curves have
a leaning-chimney shape and are shifted to lower rod concentrations on
increasing the polymer concentration.
61.30.-v - Liquid crystals.
61.30.St - Lyotropic phases.
82.70.Dd - Colloids.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001