IWNET12
IWNET12
Coupling reactions and molecular conformations in the modeling of
shear banding in wormlike micelar systems
Antony N. Beris1, Natalie Germann2 and L. Pam Cook2
1 Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716 USA
2 Department of Mathematical Sciences, University of Delaware, Newark, DE 19716, USA
Abstract
In the last decade considerable interest has emerged in understanding and modeling the ow behavior of concen-
trated wormlike micellar solutions. A signi cant advance was made through the two species modeling approach,
explicitly considering the wormlike micelles breakdown and reconstruction, originally proposed by one of us and
co-workers [1]. In the present work we revisit this model from a nonequilibrium thermodynamics point of view.
We show how, employing an extension to the nonequilibrium treatment of chemical reactions that originally
appeared in [2], we can develop a model based on nonequilibrium thermodynamics principles, modeling the
wormlike micelles with one mode viscoelastic models, that is close to the one developed based on more ad-hoc
assumptions in [1]. Using a two- uid modeling approach we introduce shear-induced migration and allow for
a systematic coupling between the number density balance equations and the rodlike micellar conformations.
Thus, we not only validate that model, but we also now have a mechanism to systematically further generalize
it, leading to considerable re nements. One such re nement, including a third species in the model, is explored
in this work. In addition to developing model predictions in simple (homogeneous) shear and extensional ows,
further applications, involving nonhomogeneous structure formation, will be discussed
References
[1] P. A. Vasquez, G. H. McKinley, and L. P. Cook. A network scission model for wormlike micellar solutions:
I. Model formulation and viscometric ow predictions. J. Non.-Newtonian Fluid Mech., 144:122-139, 2007.
[2] A. N. Beris and B. J. Edwards. Thermodynamics of Flowing Systems. Oxford University Press, New York,
1994.
E-mail: beris@UDel.Edu