Implementation of dynamic coupling in hybrid Molecular Dynamics–Lattice Boltzmann approach: Modeling aggregation of amphiphiles

Amphiphile-based aggregates are extensively used in numerous applications for encapsulation, storage, transport and delivery of toxic, active molecules due to the structural properties of the aggregates. The properties of the aggregates in turn are dictated by the molecular architecture of the amphiphiles. A complete understanding of the multiscale architecture–structure–function relationship for amphiphile-based aggregates requires the simultaneous resolution of the self-assembly of amphiphilic molecules along with an understanding of the role of various long range physical interactions including hydrodynamics. A multiscale computational approach such as the hybrid Molecular Dynamics–Lattice Boltzmann technique is able to fulfill most of those requirements. However, existing implementations only account for static coupling between the Molecular Dynamics technique and the Lattice Boltzmann method, and hence are unable to resolve the changes in the solvent-amphiphile interface during processes such as self-assembly and interfacial adsorption. In this study, a new implementation incorporating a dynamic coupling scheme between the Molecular Dynamics technique and the Lattice Boltzmann method is introduced so as to resolve dynamical changes in interfaces. The application of the new implementation to the self-assembly of phospholipids yields results which are in good agreement with computation, experiments and theory. In particular, we found the scaling exponent α of the cluster number (N(t) = C t^α) to be ~1. The previous version of this program (AEPH_v1_0) may be found at http://dx.doi.org/10.1016/j.cpc.2013.03.024.