This article reports synthesis and characterization of silver nanoparticles (AgNPs) in different concentrations of aqueous solutions of 1-octyl-3-methylimidazlium chloride ([C8mim]Cl), 1-octyl-3-methylimidazlium bromide ([C8mim]Br), 1-decyl-3-methylimidazlium bromide ([C10mim]Br), 1-dodecyl-3-methylimidazlium bromide ([C12mim]Br), sodium dodecyl sulfate (SDS) and dodecyltrimethyl ammonium bromide (DTAB) as stabilizer at 298.15 K. The effects of type, alkyl chain length and concentration of surfactants on the size, concentration and stability of AgNPs were investigated by Ultraviolet-Visible spectroscopy (UV–Vis), Transmission Electron Microscopy (TEM), Small Angle X-ray Scattering (SAXS) and Dynamic Light Scattering (DLS). The length of alkyl chain of surfactants is determining factor in stability of nanoparticles so that the surfactants with 8 or less carbon atoms have no enough protecting effects and the synthesized AgNPs tend to coalesce immediately. Increase in the alkyl chain length from C8 to C12 led to increase in stability and concentration of AgNPs. It seems that, the hydrophobic interactions between surfactants and surface of AgNPs have more important role in the stability of silver nanoparticles and the order of stabilizing effect of the investigated surfactants is as: SDS > DTAB > [C12mim]Br > [C10mim]Br.
