What can be learnt from the comparison of multiscale brownian dynamics simulations, nuclear magnetic resonance and light scattering experiments on charged micelles?

Abstract

We investigate the dynamical behavior of charged micelles with a novel multiscale Brownian Dynamics simulation and two different experimental methods, Pulsed field Gradient Nuclear Magnetic Resonance, which gives access to self-diffusion coefficients, and Dynamic Light Scattering, which provides mutual diffusion coefficients. The simulation method is a very efficient multiscale procedure which relies on a separated treatment of micelle–microions interactions and micelle–micelle interactions. From this unique combination of methodologies, the size and the charge of the micelles could be fitted. This is the first time a simulation including both electrostatic and hydrodynamic interactions between all the solutes (nanoparticles and microions) is directly compared to experiments in order to characterize nanoparticles. The size, the bare charge and the effective charge we deduce from this study are thus much more reliable than those obtain from more approximative analytical theories. We could therefore reassess quantitatively the evolution of the micelle charateristics with the concentration in added salt.