Fabrication of Synthetic Nanopores in Thin Films for Studies of Analytical Applications

Résumé du livre

ABSTRACT: The goal of this research is to develop nanoporous membrane devices for resistive-pulse sensing or separation applications. The first part of the research involves the fabrication of single conical nanopore in poly(ethylene terephthalate) (PET) membranes. A model analyte poly(styrene sulfonate) (PSS) was driven electrophoretically through the nanopore and the corresponding ion current pulses were observed. The effects of the supporting electrolyte pH, transmembrane potential and concentration of polyelectrolyte on pulse frequency were studied. The second part of the research involves developing a multi cycle chemical etch method for fabrication of a single or multiple pyramidally shaped nanopore in muscovite mica membrane. The effects of the etchant concentration, applied transmembrane potential and number of etch cycles on nanopore opening sizes and geometry were studied in detail. A significant ion current rectification was observed in such a single pyramidally shaped nanopore embedded mica membrane. In the third part, a new mechanism for improving the resistive pulse signal intensity was investigated by using single pyramidal nanopore in mica. The experimental results were the same as what we predicted based on this hypothesized mechanism, the pulse signals were current drops when the particles transported from tip to base and the pulses were current enhancement when the particles transported from base to tip in the nanopore.