Fabrication and Characterization of Single Pores for Modeling Mass Transport across Porous Membranes

An Au membrane containing a single pore was fabricated using a template approach. The pore diameter is defined by the diameter of a glass fiber template and the pore length by the amount of Au electroplated over a seed pore. The utility of the single pore for modeling mass transport is demonstrated by configuring the pore as a Coulter counter to monitor the transport of 440 nm diameter polystyrene spheres. An important advantage of this Au membrane model is that the pore surface chemistry can be modified with a self-assembled monolayer. However, the metallic Au surface also requires minimizing the exposed membrane area in order to reduce the interfering charging/faradaic current and to shorten the instrumental response time.