Electro-osmotic flow through nanopores in thin and ultrathin membranes

Dmitriy V. Melnikov, Zachery K. Hulings, Maria E. Gracheva
2017 Physical review. E  
4 We theoretically study how the electroosmotic fluid velocity in a charged cylindrical nanopore in a thin solid state membrane depends on the pore's geometry, membrane charge, and electrolyte concentration. We find that when the pore's length is comparable to its diameter, the velocity profile develops a concave shape with a minimum along the pore axis unlike the situation in very long nanopores with a maximum velocity along the central pore axis. This effect is attributed to the induced
more » ... o the induced pressure along the nanopore axis due to the fluid flow expansion and contraction near the exit/entrance to the pore and to the reduction of electric field inside the nanopore. The induced pressure is maximal when the pore's length is about equal to its diameter while decreasing for both longer and shorter nanopores. A model for the fluid velocity incorporating these effects is developed and shown to be in a good agreement with numerically computed results.
doi:10.1103/physreve.95.063105 pmid:28709345 fatcat:romhy42uong7jmejgaptdisqaq