Mass Transport in Nanochannels (original) (raw)
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Transport properties of fluids in nanochannels: bridging nano to macro
2011
A method of calculating transport properties in nanochannels is presented in this work. The Molecular Dynamics simulation of a system of liquid argon flowing in a nanochannel formed by krypton walls was the basis for our analysis concerning transport properties and specifically diffusion coefficient, shear viscosity and thermal conductivity. It is shown that for confined systems, such as nanochannels, if one of the transport properties is known, then the others can be estimated. The simulation results reveal that all properties approach bulk values at relatively small channel widths, at about 6-7nm. Below this critical point, the wall effect on fluid atoms is strong and the transport properties change dramatically. In order to extend the calculations over rough-wall nanochannels, we apply the relation extracted for flat wall channels to channels with walls consisted of successive rectangular protrusions and cavities.
Interfacial effects and diffusion transport in nanofluidic structures
Nanofluidic systems are found naturally in geological formations and biology, but they also are implemented in technology, where mass exchange is the governing process. Here we employed recently developed multiscale model for diffusion in nanoconfinement to understand passive transport regimes in nanochannels. Hew we use a critical parameter that may help to differentiate different diffusion regimes in nanochannels. Our study shows a new insight into diffusive mass transport through nanoconfined structures and establishes relations among geometry, interface effects and mass transport kinetics.
Nature communications, 2018
Ionic transport through nanofluidic systems is a problem of fundamental interest in transport physics and has broad relevance in desalination, fuel cells, batteries, filtration, and drug delivery. When the dimension of the fluidic system approaches the size of molecules in solution, fluid properties are not homogeneous and a departure in behavior is observed with respect to continuum-based theories. Here we present a systematic study of the transport of charged and neutral small molecules in an ideal nanofluidic platform with precise channels from the sub-microscale to the ultra-nanoscale (<5 nm). Surprisingly, we find that diffusive transport of nano-confined neutral molecules matches that of charged molecules, as though the former carry an effective charge. Further, approaching the ultra-nanoscale molecular diffusivities suddenly drop by up to an order of magnitude for all molecules, irrespective of their electric charge. New theoretical investigations will be required to shed ...