Anomalous decline of water transport in covalently modified carbon nanotube membranes.

Carbon nanotube membranes have been shown to rapidly transport liquids; but progressive hydrophilic modification--contrary to expectations--induces a drastic reduction of water flow. Enhanced electrostatic interaction and the disruption of the mechanically smooth graphitic walls is the determinant of this behavior. These results have critical implications in the design of nanofluidic devices.