화학공학소재연구정보센터
Fluid Phase Equilibria, Vol.362, 177-186, 2014
Steric effects on ion dynamics near charged electrodes
We present a modified Poisson-Nernst-Planck (mPNP) model to include steric effects on ion dynamics near charged electrodes. This contribution appears directly on chemical potential of each ion in solution as a non-electrostatic term. The model consists in a partial-differential-algebraic equation (PDAE) system, which after spatial discretization was solved by the well-established DASSLC code, implemented in EMS() simulator. A careful dimensional analysis was carried out to turn the PDAE system dimensionless with normalized spatial domain. Size correlation (SC) effects for equally sized ions avoid unphysical charge densities near the electrodes (especially at high voltages), and also give some insights on double layer formation. Time evolution of free charge density profiles show a diffusion controlled dynamics with a very fast response (t similar to 10(-8) s). The methodology proposed here allows the inclusion of new contributions on PNP model framework for ion dynamics, as well as to solve both stationary and dynamical ion distributions, taking advantage of the EMSO software simulator features. (C) 2013 Elsevier B.V. All rights reserved.