Ratcheting in Nanofluids : Role of confining surface fluctuations

We consider the effect of surface undulations of nanochannels on the motion of particles in it. We report the mechanism of surface induced ratcheting transport of particles against fluid flow in nano channels. We show that, the typical number for the velocity of ratcheting particles could be of the order of 50 nm/sec. This is a considerably large effect which could be used for application in efficient filtration of particles smaller than the width of nanopores.