High performance water transport in nanopores has drawn a great deal of attention in a variety of applications, such as water desalination, power generation, and biosensing. High water transport enhancement factors in carbon-based nanopores have been reported over the classical Hagen–Poiseuille (HP) equation which does not account for the physics of transport at molecular scale. Instead, comparing the experimentally measured transport rates to that of a theory, that accounts for the microscopic physics of transport, would result in enhancement factors approaching unity. Such a theory is currently missing. Here, molecular corrections are introduced into the HP equation by considering the variation of key hydrodynamical properties (viscosity and friction) with thickness and diameter of pores in ultrathin graphene and finite-length carbon nanotubes (CNTs) using Green–Kubo relations and molecular dynamics (MD) simulations. The corrected HP (CHP) theory successfully predicts the permeation rates from nonequilibrium MD pressure driven flows. The previously reported enhancement factors over no-slip HP (of the order of 1000) approach unity when the permeations are normalized by the CHP flow rates. The results of our study will help better understand nanoscale flows in carbon-based pores and tubes.
Mohammad Heiranian obtained his B.E in mechanical engineering from the University of Manitoba, Canada, in 2012 and his M.S in theoretical and applied mechanics from the University of Illinois at Urbana-Champaign in 2016. Currently, he works on his PhD under the supervision of professor Narayana Aluru at Illinois. His research is focused on designing novel advanced materials to solve challenges in water, energy and health. Using extensive molecular dynamics simulations, he studies the properties of different systems in nanoscale to understand their underlying fundamental physics and then apply that knowledge to engineer advanced materials for applications in water purification, electricity production and DNA/protein detection for health purposes.
Host: Professor Narayan Aluru