Hyperbranched polyethyleneimine (PEI) drives straightforward in situ integration of stable silver nanoparticles onto polycarbonate support

The in situ integration of silver nanoparticles (AgNPs) onto polymeric supports has attracted considerable attention in the scientific community as a promising strategy to overcome the main limitations of conventional AgNP-based materials. In this work, we present a remarkably simple and straightforward methodology for the in situ generation of AgNPs on the surface of polycarbonate substrates, both in plates (PC) and track-etched porous membranes discs (MPC). The process is spontaneously induced by covalently bonded hyperbranched polyethyleneimine (PEI), without the need for any external reducing agent or sensitizing dye. PC–PEI hybrids were synthesized using four PEIs with different average molecular weights (M n = 600, 1800, 10,000, and 60,000 g·mol⁻¹) and thoroughly characterized by SEM, EDX, FTIR, XPS, and potentiometric measurements. The resulting hybrid materials displayed excellent Ag⁺ ion complexation capacity and efficient formation of metallic silver (Ag⁰) nanoparticles. This process was further enhanced under visible light irradiation (blue, 447 nm and green, 532 nm). The synthesized AgNPs exhibited good stability against oxidation and aggregation, attributed to the stabilizing effect of the PEI. The antibacterial activity of these materials was evaluated against Escherichia coli , showing strong inhibitory effects in both surface inoculation and filtration tests. Overall, this study provides new insights into the in situ synthesis of AgNPs on polymeric substrates through a technically competitive and sustainable methodology. The key to this simplicity lies in the versatile role of PEI, which simultaneously functions as complexing agent, reducing agent, and protective matrix, making it an essential component of the proposed strategy.