First-Principles Insights on the Electronic Structure Coupling Between Water and Carbon Nanotubes*

Water structure, dynamics and transport in nanoconfinement have been shown to exhibit anomalous behavior. Although significant experimental and theoretical progress has been made to understand water behavior inside carbon nanotubes (CNTs), the quantum effect that water experiences due to the electronic structure of the CNT has not been investigated in detail. In this presentation, we show clear evidence on the electronic structure coupling between water and CNTs. We use first-principles simulations to compute various structure and transport properties of water inside CNTs. Our results show that water molecule behavior can depend significantly on whether the CNT is metallic, semi-metallic or semiconducting. Further, we show that the electronic coupling can lead to water exhibiting interesting trends in free energy, dipole moment and friction factor. Our results provide a fundamental understanding of water inside CNTs which is crucial to design high performance nanofluidic devices for various applications including energy harvesting, water desalination, and biomimetic devices.