Carbon nanotubes （CNTs） have long been expected to be excellent nanochannels for use in desalination membranes and other bio-inspired human-made channels owing to their experimentally confirmed ultrafast water flow ...Carbon nanotubes （CNTs） have long been expected to be excellent nanochannels for use in desalination membranes and other bio-inspired human-made channels owing to their experimentally confirmed ultrafast water flow and theoretically predicted ion rejection. The correct classical force field potential for the interactions between cations and CNTs plays a cru- cial role in understanding the transport behaviors of ions near and inside the CNT, which is key to these expectations. Here, using density functional theory calculations, we provide classical force field potentials for the interactions of Na＋/hydrated Na＋ with （7,7）, （8,8）, （9,9）, and （10,10）-type CNTs. These potentials can be directly used in current popular classical soft- ware such as nanoscale molecular dynamics （NAMD） by employing the tclBC interface. By incorporating the potential of hydrated cation-g interactions to classical all-atom force fields, we show that the ions will move inside the CNT and accu- mulate, which will block the water flow in wide CNTs. This blockage of water flow in wide CNTs is consistent with recent experimental observations. These results will be helpful for the understanding and design of desalination membranes, new types of nanofluidic channels, nanosensors, and nanoreactors based on CNT platforms.展开更多
基金Project supported by the National Science Fund for Outstanding Young Scholars of China(Grant No.11722548)the National Natural Science Foundation of China(Grant Nos.11574339 and 11404361)
文摘Carbon nanotubes （CNTs） have long been expected to be excellent nanochannels for use in desalination membranes and other bio-inspired human-made channels owing to their experimentally confirmed ultrafast water flow and theoretically predicted ion rejection. The correct classical force field potential for the interactions between cations and CNTs plays a cru- cial role in understanding the transport behaviors of ions near and inside the CNT, which is key to these expectations. Here, using density functional theory calculations, we provide classical force field potentials for the interactions of Na＋/hydrated Na＋ with （7,7）, （8,8）, （9,9）, and （10,10）-type CNTs. These potentials can be directly used in current popular classical soft- ware such as nanoscale molecular dynamics （NAMD） by employing the tclBC interface. By incorporating the potential of hydrated cation-g interactions to classical all-atom force fields, we show that the ions will move inside the CNT and accu- mulate, which will block the water flow in wide CNTs. This blockage of water flow in wide CNTs is consistent with recent experimental observations. These results will be helpful for the understanding and design of desalination membranes, new types of nanofluidic channels, nanosensors, and nanoreactors based on CNT platforms.
