We investigate the effect of wall roughness on water electrolyte transport characteristics at different temperatures through carbon nanotubes by using nonequilibrium molecular dynamics simulations. Our results reveal that shearing stress and the nominal viscosity increase with ion concentration in corrugated carbon nanotubes (CNTs), in contrast to cases in smooth CNTs. Also, the temperature increase leads to the reduction of shearing stress and the nominal viscosity at moderate degrees of wall roughness. At high degrees of wall roughness, the temperature increase will enhance radial movements and increases resistance against fluid motion. As the fluid velocity increases, the particles do not have enough time to fully adjust their positions to minimize system energy, which causes shearing stress and the nominal viscosity to increase. By increasing roughness amplitude or decreasing roughness wavelength, the shearing stress will increase. Synergistic effects of such parameters (wall roughness, velocity, ion concentration, and temperature) inside corrugated CNTs are studied and compared with each other. The molecular mechanisms are considered by investigating the radial density profile and the radial velocity profile of confined water inside modified CNT.

• Received 18 March 2014

DOI:https://doi.org/10.1103/PhysRevE.90.012304