One dimensional aggregates of silver nanoparticles induced by the stabilizer 2-mercaptobenzimidazole

Silver colloids stabilized by a specially designated molecule, 2-mercaptobenzimidazole (MBMZ), were prepared in a 50:50 (v/v) aqueous ethanol solution. A number of wire-like configurations impregnated with Ag nanoparticles were identified in the TEM images as the concentration of MBMZ passed beyond a certain value. Moreover, the aggregates of Ag nanocrystals were probed in solution by UV-vis and dynamic light scattering (DLS) measurements. UV-vis and DLS also revealed that the aggregation and aggregate growth of Ag nanocrystals occurred upon aging the aqueous ethanol solutions, which initially contain isolated particles. In addition, two control systems of which control system I and II were, respectively, 2-mercaptobenzothiazole (MBTZ) and [MBMZ(.)C(2)H(5)]Br-+(-) (see the Experimental Section of this paper) stabilized silver colloids were prepared and studied. The hydrogen bonding (i.e., N-(HN)-N-... interactions) between MBMZ molecules on the surfaces of different Ag nanoparticles is believed to be the driving force for the formation of wire-like aggregates, which is evidenced by comparing the FTIR of MBMZ-stabilized Ag nanoparticles with that of control system H.