This research presents the results of a study of the photograft copolymerization of functional monomers of methacrylic acid (MAA) and 2-hydroxyethyl methacrylate (HEMA) and the following formation of interpolyelectrolyte complexes with poly(allylamine) onto track-etched membranes based on poly(ethylene terephthalate) (PET TeMs) with a pore diameter of 300 ± 20 nm. The effect of various parameters and conditions on the efficiency of the grafting process has been studied: irradiation time, monomer concentration, and the effect of the nature of the solvent has been considered. Modified membranes were characterized by advanced physical and chemical methods: FTIR spectroscopy, SEM, contact angle, thermogravimetry and gas permeability. Using magnetron sputtering, electrodes based on modified membranes were obtained. The sensor has been tested in the detection of cadmium and lead cations in the concentration range from 0.05 to 4.25, 6.25 mg/L. © 2024 Author(s).