Structure and electrochemical properties of polymeric composite membranes with a selective layer

The structure and electrochemical properties of polyethylene terephthalate track-etched membranes were studied. The membranes were covered with a solution of a styrene-butylmethacrylate copolymer on one side. The formation of a selective layer of copolymer in the pores of the starting membranes led to composite membranes characterized by asymmetric conductivity in electrolyte solutions—a rectification effect similar to the p - n transition in semiconductors. The asymmetry resulted from a considerable decrease in the pore diameter in the deposited copolymer layer, changing the pore geometry, and was also due to the existence of an interface in the pores between the starting membrane and the copolymer layer, having different levels of hydrophilicity.