In most cases described so far a potentiometric ion-selective membrane is made of one polymer (or one copolymer) used with ion-exchanger, ionophore and with a plasticizer of choice. In this work a concept of potentiometric bilayer membranes is introduced and their benefits from both theoretical and practical point of view are presented. They are related to response mechanism interpretation and to detection limit lowering of ion selective electrodes. The novel structurized bilayer potentiometric membranes represent a sequence of polyacrylate polymers with ion-exchangers (the same or different), the polymers applied were either poly(hexyl acrylate) or poly(lauryl acrylate) characterized by different ionic mobilities. It was shown that tailoring of the polymer material for the component layers, kind of ion-exchanger and the layer thickness can result in significantly improved analytical performance represented by wide linear response range and low detection limit, as shown in example of potassium-selective electrode. This effect was achieved due to controlled compensation of spontaneous ion fluxes in bilayer system. The experimental data were supplemented by digital simulation results explaining the role of the thickness of the internal layer on the ion fluxes and thus on the detection limit. (C) 2016 Elsevier B.V. All rights reserved.