Influence of Precursor Concentration on the Formation of Silver Nanoparticles with Oligostyrylmonocarboxylate Ligands in ED-20 Epoxy Oligomer

Abstract

Using transmission electron microscopy and UV–Vis spectroscopy, the effect of the concentration of the silver oligostyrylmonocarboxylate precursor in the range of 0.3–3.2 wt % in the reaction with the ED-20 epoxy resin on the formation of silver nanoparticles at a temperature of 75°C is studied. At the initial carboxylate concentration ≤0.3 wt %, silver nanoparticles with oligostyrylmonocarboxylate ligands having a spherical shape, small size, and narrow dispersion are produced. With an increase in the initial concentration of silver oligostyrylcarboxylate ≥0.3 wt %, the accumulation of nanoparticles is accompanied by the appearance of aggregates of arbitrary shape due to the van der Waals interaction of carboxylate ligands. The presence of aggregates leads to the broadening, splitting, and redshift of surface plasmon resonance peaks. Silver nanoparticles in aggregates are separated by ligand shells that reduce the probability of coalescence.