Efficient Transport Between Disjoint Nanochannels by a Water Bridge

Water channels are important to new purification systems, osmotic power harvesting in salinity gradients, hydroelectric voltage conversion, signal transmission, drug delivery, and many other applications. To be effective, water channels must have structures more complex than a single tube. One way of building such structures is through a water bridge between two disjoint channels that are not physically connected. We report on the results of extensive molecular dynamics simulation of water transport through such bridges between two carbon nanotubes separated by a nanogap. We show that not only can pressurized water be transported across a stable bridge, but also that (i) for a range of the gap's width l(g) the bridge's hydraulic conductance G(b) does not depend on l(g), (ii) the overall shape of the bridge is not cylindrical, and (iii) the dependence of G(b) on the angle between the axes of two nonaligned nanochannels may be used to tune the flow rate between the two.