(416j) Efficient Transport between Disjoint Nanochannels By Water Bridge

Water channels are important to new purification systems, osmotic power harvesting in salinity gradients, hydroelectric voltage conversion, signal transmission, such advanced conductance systems as water channel proteins, drug delivery, and many other applications. To be effective, artificial water channels must have structures more complex than a single channel. One way of building such structures is through water bridges between two channels that are not physically connected together. 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 via a stable bridge, but also that, (i) for a range of the gap's length l_g the bridge 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. Viscous dissipation develops in the bridge, whose source we describe.