Synthesis of Bilayer Composite Nanomembranes with Conductivity Asymmetry

The structure and electrochemical properties of polyethylene terephthalate track membranes modified in acetylene plasma are studied. It is found that polymer deposition on the track membrane surface using acetylene polymerization in plasma results in the case of formation of a semipermeable layer covering pores in formation of a composite nanomembrane featuring asymmetry of conductivity in solutions of electrolytes: a rectifying effect similar to that of a p-n junction in semiconductors. It is shown that the observed effect of conductivity asymmetry is caused by a significant decrease in the diameter of pores in the plasma-deposited polymer layer and a change in the pore geometry, same as existence of an interface between the initial membrane and polymer layer that have a different concentration of carboxyl groups in the surface layer. The impedance spectroscopy method allowed obtaining information on ion transfer in the studied membranes.