Room temperature surfactant assisted crystal growth of silver nanoparticles to nanoribbons

This study presents a simple and systematic growth of Ag nanoparticles (NPs) to nanoribbons by changing the hydrophobicity parameter of a series of cationic Gemini surfactants by using seed-mediated approach in aqueous phase at room temperature. At lowest hydrophobicity of a Gemini surfactant (i.e., dimethylene bis(decyldimethyl-ammonium bromide), 10-2-10), Ostwald ripening process was observed which caused fusion among growing Ag NPs. This process was quite prominent when 0.5 ml of Ag seed solution was used for the growth process but weakened as the amount of seed decreased to 0.125 ml. Similar behavior was demonstrated by Au NPs studied for comparison. The nanostructures were characterized by TEM, XRD, and UV-visible measurements. Further increase in the hydrophobicity of a Gemini surfactant from 10-2-10 to dimethylene bis(tetradecyldimethylammonium bromide) (14-2-14) through dimethylene bis(dodecyldimethylammonium bromide) (12-2-12), resulted in the participation of threads like micelles and liquid crystalline phase as soft-templates towards the nanoribbon formation. Fine polycrystalline Ag nanoribbons were obtained in the presence 14-2-14 and were characterized by the HRTEM and EDX analysis.