Single-Domain Ferroelectric Water and its Concerted Diffusion in Nanotubes

The term ‘ferroelectric water’ has so far stood for ‘ferroelectric ice.’ In molecular dynamics simulations, we find that, counter to intuition, single-domain ferroelectric water is possible inside carbon nanotubes open to a liquid water reservoir. Though this water is tube-shaped, it is strikingly different in structure and dynamics from ‘ice nanotubes.’ A series of step-wise changes in net polarization of water and mobile/immobile water transitions are observed to occur spontaneously. This study not only improves our general knowledge of water, but is also suggestive of potential multifunctional capabilities of simple hydrophobic nanotubes for future applications.