Dissipative particle dynamics: Effects of thermostating schemes on nano-colloid electrophoresis

Abstract

A novel fully explicit approach using dissipative particle dynamics (DPD) method is introduced in the present study to model the electrophoretic transport of nano-colloids in an electrolyte solution. Slater type charge smearing function included in 3D Ewald summation method is employed to treat electrostatic interaction. Performance of various thermostats are challenged to control the system temperature and study the dynamic response of colloidal electrophoretic mobility under practical ranges of external electric field (0.072<E<0.361 v/nm) covering linear to non-linear response regime, and ionic salt concentration (0.049 <SC<0.69 [M]) covering weak to strong Debye screening of the colloid. System temperature and electrophoretic mobility both show a direct and inverse relationships respectively with electric field and colloidal repulsion; although they each respectively behave direct and inverse trends with salt concentration under various thermostats. Nosé–Hoover–Lowe–Andersen and Lowe–Andersen thermostats are found to function more effectively under high electric fields (E>0.145v/nm) while thermal equilibrium is maintained. Reasonable agreements are achieved by benchmarking the system radial distribution function with available EW3D modellings, as well as comparing reduced mobility against conventional Smoluchowski and Hückel theories, and numerical solution of Poisson–Boltzmann equation.