Charge-Induced Stabilization of Ultralong Water Bridges between Disjoint Carbon Nanotubes

The formation of water bridges between disjoint carbon nanotubes is pivotal for long-distance water transport in nanofluidic systems. The impact of tip-localized charges on the structural integrity and transport properties of these bridges was investigated using molecular dynamics simulations. Tip charging is found to dramatically extend the maximum stable gap of water bridges from 8 Å to 36 Å, a distance exceeding the molecular diameter of water by more than an order of magnitude. This structural stabilization stems from a charge-induced reinforcement of the hydrogen bond network and a significant increase in the local ordering of water molecules at the CNT tips. However, this structural robustness comes at the expense of transport efficiency, as the elevated energy barrier for water translocation leads to a marked reduction in flux. These findings elucidate the dual regulatory role of electrostatic interactions in nanofluidic bridges, providing a critical theoretical framework for the design of next-generation devices that balance long-range stability with high transport flux.