Fluid flow in charged nanotubes

The dynamics of fluid flow through nanochannels is different from those in macroscopic systems. By using the molecular dynamics simulations, we investigate the influence of surface polarity of nanotube on the transport properties of the water fluid. The nanotube used here resembles the carbon nanotube, but carries charges of q on some atoms; overall, the nanotube is charge-neutral. Our simulation results show that water flux decreases sharply with the increasing of q for q < 1.6 e; however, the water flux for shells far away from nanotube wall increases slightly when q > 1.6 e. The mechanism behind the interesting phenomenon is discussed. Our findings may have implications for development of nano-fluidic devices and for understanding the movement of confined fluid inside the hydrophilic nanochannel.