(648h) Mass and Charge Transfer Resistance at Interfaces

Mass and charge transfer across interfaces between bulk solutions is critical in numerous natural, industrial and biological processes. The traditional solution-diffusion model used to characterize such transfer assumes local chemical equilibrium at interfaces. However, it is plausible such that an assumption may not hold at all interfaces when the inhomogeneity imposes barriers to transport across interfaces. In this talk, we extend the ideas of Onsager transport theory to that of interfaces, by introducing the concepts of interfacial mass and charge transfer resistance, which can delay local equilibrium at the interface and can affect overall species transport. We consider problems related to relaxation of nonelectrolyte and electrolyte concentration jumps across bulk solutions. By using analytical theory and computer simulations, we show that the solution-diffusion model represents a limiting case of negligible interfacial resistance or large system size. For reduced system sizes, however, interfacial resistance becomes increasingly significant, resulting in mass and charge relaxation dynamics that deviate markedly from the conventional solution-diffusion predictions. Our results imply the significance of interfacial resistances in microscopic systems with strong confinements such as thin films, nanodroplets, and membraneless organelles in biological systems.