The development of composite materials consisting of metal nanoparticles embedded in macromolecular compounds, obtained via in-situ reduction process has attracted research interest. Silver nanoparticles (AgNPs) have been synthesized by a one-step method at 25 °C, that involves photo-reduction of AgNO3 dissolved in a solution of oligomers which promoted Ag∘ generation. These highly functionalized oligomers, obtained from ethylene glycol diglycidyl ether (EGDE), imidazole and methacrylic acid, were tested as reagents in photo-reduction/NP stabilization. Their functional groups acted as ligands on coordinating Ag+ and then stabilizing AgNPs, being particularly involved ether function of EGDE, according to DLS and FT-IR evidence. These organic macromolecules strongly promoted the adherence of AgNP-oligomers structures to polystyrene substrate. The composite materials were further characterized by UV–visible spectroscopy, electrochemical methods, SEM and TEM. The antimicrobial activity of the polystyrene surface modified with AgNP-oligomers was studied, concluding that it had biocidal activity against Gram positive and Gram negative bacteria. © 2020 Elsevier B.V.