Preparation and water flow velocity measurement of a large diameter single-wall carbon nanotube

To fill the gap in the measurement of large diameter single-wall carbon nanotube (SWCNT) and further predict the variation rule of mass flux versus diameter, this work measured the water flow velocity and mass flux coefficient in an individual SWCNT with a 3.07 nm diameter. A mechanical method is used to obtain the large diameter SWCNT by removing the internal tube of a double-wall carbon nanotube, and then the water flow velocity through this SWCNT was measured by an electrical method. The water flow velocity of large diameter SWCNT can reach to 146.1 ± 32.5 μm s−1, and the enhancement factor compared with no-slip Hagen–Poiseuille relation is about 14.5. A mass flux coefficient is defined to describe the mass flow ability through SWCNT and calculated by the experiment data. Although the enhancement factor decreased to ∼1/4 of the normal size SWCNT (∼1.5 nm), the mass flux coefficient in the large diameter SWCNT increased efficiently, and which is about 5.7 times to the normal size SWCNT. Based on the above measurement result, a reported simulation result can be revised and then verified to describe the enhancement factor versus diameter, and the mass flux coefficient of the SWCNT can be further predicted. According to the prediction result, in the bulk-like liquid region, the mass flux of an individual SWCNT can reach to maximum when the diameter is around 2.9 nm, which would provide a new idea for the design of the SWCNT-based nanodevices in the future.