Pressure-driven flow through a single nanopore

We have measured the flow of gas through single ion track pores in a polymer film using a mass spectroscopy technique. The pores are 12 μm long with diameters in the range of 50-1000 nm, and the flow was driven by pressure drops in the range 0-30 atm. When the mean free path is large compared to the pore diameter (large Knudsen number Kn), the flow rate is proportional to the pressure drop and the pore radius R cubed, and is consistent with a model of diffusive scattering at the pore walls. For Kn≤0.1, the hydrodynamic conductance increases, as predicted by standard kinetic theory models, and finally approaches the conventional Poiseuille value with zero slip length.