Modelling the rheology of anisotropic particles adsorbed on a two-dimensional fluid interface.
We present a general approach based on nonequilibrium thermodynamics for bridging the gap between a well-defined microscopic model and the macroscopic rheology of particle-stabilised interfaces. Our approach is illustrated by starting with a microscopic model of hard ellipsoids confined to a planar surface, which is intended to simply represent a particle-stabilised fluid-fluid interface. More complex microscopic models can be readily handled using the methods outlined in this paper. From the aforementioned microscopic starting point, we obtain the macroscopic, constitutive equations using a combination of systematic coarse-graining, computer experiments and Hamiltonian dynamics. Exemplary numerical solutions of the constitutive equations are given for a variety of experimentally relevant flow situations to explore the rheological behaviour of our model. In particular, we calculate the shear and dilatational moduli of the interface over a wide range of surface coverages, ranging from the dilute isotropic regime, to the concentrated nematic regime.
ETH Zürich, Department of Materials, Polymer Physics, CH-8093 Zürich, Switzerland. aluo@mat.ethz.ch.
Alan M
AM
Luo
Leonard M C
LM
Sagis
Hans Christian
HC
Öttinger
Cristiano
C
De Michele
Patrick
P
Ilg