Simulation of water impregnation through vertically aligned CNT forests using a molecular dynamics method

The flow rate of water through carbon nanotube (CNT) membranes is considerably large. Hence, CNT membranes can be used in nanofluidic applications. In this work, we performed a molecular dynamics (MD) simulation of the introduction of water into CNTs in the CNT membranes, especially in vertically aligned CNT forests. The results showed that the Knudsen number ( Kn ) increased with an increasing volume fraction of CNT ( V C ) and was greater than 10 −3 for each V C . Beyond this value, the flow became a slip flow. Further, the permeability increased as V C increased in the actual state calculated by the MD simulation, whereas the permeability in the no-slip state predicted by the Hagen–Poiseuille relationship decreased. Thus, a clear divergence in the permeability trend existed between the states. Finally, the flow enhancement ranged from 0.1 to 23,800, and the results show that water easily permeates as V C increases.