Modulating water transport in fractured carbon nanotubes: The role of terahertz electric fields and nanotube geometry

The formation of sub-nanometre fracture gaps in single-walled carbon nanotubes (SWCNTs) represents a major limitation to their efficiency in transporting water. Through molecular dynamics simulations, this work demonstrates that the water flux exhibits a threshold response to the fracture gap. In a 1.34 nm SWCNT, fractures smaller than 3 Å exert negligible influence, whereas fracture gaps exceeding this threshold cause a pronounced reduction in flux. Furthermore, in longer nanotubes, the smoother free energy profile in the central region and more stable water-nanotube interactions facilitate the formation of stable single-file water chains, endowing them with enhanced resistance to fracture. Under the influence of a terahertz electric field, the hydrogen bond network between water molecules is disrupted, which leads to substantial flux enhancement but also to increased sensitivity to fracture spacing. These findings provide new theoretical insight into the interplay between structural defects and external stimuli in nanoscale water transport and offer guidance for designing robust, high-performance SWCNT-based nanofluidic systems.