Impact of Polyelectrolyte Multilayers on the Ionic Current Rectification of Conical Nanopores

Single conical nanopores were functionalised layer by layer with weak polyelectrolytes. We studied their influence on the ionic diode properties We have considered different couples of polyelectrolytes: poly-L-lysine/poly(acrylic acid) and poly(ethyleneimine)/poly(acrylic acid) as well as the influence of cross-linking. The results show that the nanopores decorated with poly(ethyleneimine)/poly(acrylic acid) exhibit an interesting behavior. Indeed, at pH 3, the nanopore is open only at the low salt concentration, while at pH 7, it is already open. The nanopores functionalized with poly-L-lysine/poly(acrylic acid) do not show an inversion of ionic transport properties with the pH as expected. After cross-linked to prevent large conformational changes, the ionic diode properties are dependent on the pH.