Figure 1.

Schematic of the system. Water and ions are transported from reservoir A to reservoir B through the CNT. The potential variation is detected as the hydrated ions pass through the CNT. The system can be used to detect the polarity of the ions as well as the rate of transport. The measuring point is located above the center of the CNT at a distance of 0.15 nm from the nanotube surface. The size of the simulation box for the (16, 0) CNT case is 3.20000×3.20000×8.69289 nm³ and for the (10, 10) CNT case is 3.20000×3.20000×8.7682 nm³. These simulation boxes are large enough to mimic a bulk water environment according to the work of Hummer et al. (Ref. ³).