Ionic Transport through Double Nanopores through Simulation

Porous graphene has a widely application in different fields due to its special properties, especially in the biological micro-nano field. Exploring the transport properties of porous graphene to electrolytes is of great significance in electric nanorobot manipulation and DNA detection and so on. Here, we use molecular dynamics simulation to investigate the transport properties of electrolytes through double-porous graphene under an applied electric field. We find that due to the blocking effect of graphene, the ion concentration polarization layers of both K ions and Cl ions are formed respectively on each side of the graphene. Besides, the two layers have a different distance from graphene nanopore center. The reason is probably because of the different magnitudes in van der Waals interactions between the two kinds of ions with the carbon atoms in the graphene sheet. We analyze the ion flow field and current distribution, and the results show: compared with K ions, Cl ions have higher mobility in double-porous graphene and are more inclined to pass through nanopores with larger pore sizes. Besides, we find the diameters of the nanopore will have an impact on the resistivity of the ion through the nanopore of graphene.