A many-body dissipative particle dynamics parametrisation scheme to study behaviour at air–water interfaces

Abstract

The many-body dissipative particle dynamics parametrisation scheme developed in this work allows us to predict the surface tension and conformation of surfactants at air/water interfaces.

Computational predictions of interfacial tension, surface tension, and surfactant adsorption isotherms

“…However, it should be noticed that within the framework of atomistic simulations, it is relatively easy for surfactants to become overpacked at the interface and the surface layer in the simulation box to become metastable, compared to multibody dissipative particle dynamics (M-DPD) simulations. 114 Surfactants prefer to stay at an interface in AA MD even when the number of molecules leads to Γ MAX being exceeded. The experimental Γ MAX will occur at the CMC, when the chemical potential of the monomers at the interface is the same as that in solution and micelles.…”

“…With further validation, the MD-MTT framework could be extended to predict both ionic surfactants and non-ionic surfactants at the water-oil and water-vacuum interface, with the help of the force fields refined in this paper. 121,122 In combination with CMCs calculated directly from dissipative particle dynamics (DPD) simulations, [123][124][125][126][127] or slightly more expensive approaches such as many-body dissipative particle dynamics (M-DPD) 114 or coarse-grained molecular dynamics, 128 this provides a way to fully predict G MAX , g CMC , CMC and the adsorption isotherm of surfactants directly from simulation.…”

Many-body dissipative particle dynamics simulations of micellization of sodium alkyl sulfates

“…60 In this work, we will base our parameterisation on reproducing experimental activity coefficients at infinite dilution γ ∞ (IDACs), an approach which has also been used by various previous authors. 29,38,57,61…”

“…To find a general relationship between a TT and the bead density ρ , we perform a parameter sweep in the range −26 ≤ a TT ≤ −18, with an interval of Δ a TT = 1. We simulate two bonded beads to represent octane with an equilibrium bond length of l 0 = 0.6 (note that we make our initial choice of bond length based on results from our previous work, 61 more details of which can be found in the ESI†). These simulations are conducted in the const-NVT ensemble, in a box with periodic boundaries with dimensions 10 r C × 10 r C × 100 r C .…”