A Ternary Lattice Boltzmann Model for Amphiphilic Fluids

TL;DR

This paper introduces a ternary lattice Boltzmann model for simulating amphiphilic fluids, capturing complex interactions and structures more efficiently than previous models, and providing new insights into fluid dynamics.

Contribution

It presents a novel ternary lattice Boltzmann model that conserves mass for each species and models microscopic interactions without free energy functionals.

Findings

Successfully simulates lamellar structures in amphiphilic fluids.

Shows differences in phenomenology compared to lattice-gas models.

Enables efficient computer simulation and theoretical analysis.

Abstract

A lattice Boltzmann model for amphiphilic fluid dynamics is presented. It is a ternary model, in that it conserves mass separately for each chemical species present (water, oil, amphiphile), and it maintains an orientational degree of freedom for the amphiphilic species. Moreover, it models fluid interactions at the microscopic level by introducing self-consistent forces between the particles, rather than by positing a Landau free energy functional. This combination of characteristics fills an important need in the hierarchy of models currently available for amphiphilic fluid dynamics, enabling efficient computer simulation and furnishing new theoretical insight. Several computational results obtained from this model are presented and compared to existing lattice-gas model results. In particular, it is noted that lamellar structures, which are precluded by the Peierls instability in two-dimensional systems with kinetic fluctuations, are not observed in lattice-gas models, but are easily found in the corresponding lattice Boltzmann models. This points out a striking difference in the phenomenology accessible to each type of model.