LAUSR

Ultrafast water permeation in aquaporins is promoted by their hydrophobic interior surface. Polytetrafluoroethylene has a dense fluorine surface, leading to its strong water repellence. We report a series of fluorous oligoamide nanorings with interior diameters ranging from 0.9 to 1.9 nanometers. These nanorings undergo supramolecular polymerization in phospholipid bilayer membranes to form fluorous nanochannels, the interior walls of which are densely covered with fluorine atoms. The nanochannel with the smallest diameter exhibits a water permeation flux that is two orders of magnitude greater than those of aquaporins and carbon nanotubes. The proposed nanochannel exhibits negligible chloride ion (Cl–) permeability caused by a powerful electrostatic barrier provided by the electrostatically negative fluorous interior surface. Thus, this nanochannel is expected to show nearly perfect salt reflectance for desalination. Description Fluorine for faster water transport Typically, as the diameter of a pipe or channel is shrunk, the flow rate per cross-sectional area will decrease because of the greater surface area to volume ratio. Itoh et al. designed a series of fluorous oligoamide nanorings that undergo supramolecular polymerization to form nanochannels with dense packing of organofluorine groups (see the Perspective by Shen). The intense electronegativity disrupts the formation of water clusters, so that individual water molecules flow through the smallest channels faster than through larger ones. Chloride ions are strongly repelled and cannot travel through the channels. —MSL Oligoamide nanoring-based fluorous nanochannels in bilayer membranes enable ultrafast water permeation and desalination.