Effects of electrolytes and surfactants on the morphology and stability of advanced silver nano-materials

The impact of electrolytes, stabilizing and/or capping agents on morphology of colloidal silver nano-materials (AgNPs) has been studied spectroscopically. Sodium thiosulfate acts as reducing-, stabilizing- and damping-agents. Stoichiometric ratios of S2O32− and Ag+ ions were responsible to the formation stable and prefect transparent dark yellow colored AgNPs. The S2O32−-stabilized AgNPs were significantly more stable in inorganic electrolytes (NaNO3, Na2SO4, Na2CO3 and KBr). S2O32− is adsorbed more strongly than the used other anions. The addition of cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) has significant effects on the absorbance of S2O32−-stabilized AgNPs which can be rationalized in terms of electrostatic attraction and repulsion between the adsorbed S2O32− ions on to the surface of AgNPs and cationic and/or anionic head groups of used surfactants, respectively. Transmission electron microscopy images suggest that AgNPs are polydispersed, spherical and exhibiting an interesting irregular morphology.

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► Stoichiometric ratio of S2O32− and Ag+ ions are responsible to the formation of prefect transparent yellow colored silver sol.
► Higher S2O32− concentrations has damping effect.
► Head group of the surfactants and nature of the electrolytes have significant effect on the stability of silver nanoparticles.