Silver nanoparticle in situ growth within crosslinked poly(ester-co-styrene) induced by UV irradiation: aggregation control with exposure time

Silver nanoparticles (NPs) were photogenerated in situ in crosslinked poly(ester-co-styrene) resins (self-standing films and monoliths) by irradiating the samples with UV light. Addition of the silver salt solution did not interfere in the resin curing process and silver reduction was not detected during sample crosslinking. The samples were characterized by absorption spectroscopy and transmission electron microscopy. The initially broad and asymmetric surface plasmon resonance band was narrowed and blue-shifted as the exposure time to UV light was increased. Samples illuminated up to 120 min have an average particle size near 9.0 nm; a decrease to ∼5.0 nm was observed for longer exposure times up to 790 min. The asymmetric surface plasmon resonance band was due to particle aggregation; higher irradiation times led to a uniform particle distribution within the polymer matrix.