Nucleation and growth kinetics of silver nanoparticles prepared by glutamic acid in micellar media

The title reaction in the presence of cetyltrimethylammonium bromide (CTAB) has been followed spectrophotometrically at 325 nm. In the process of reduction, characteristic surface resonance plasmon absorption peaks appear for the silver nanoparticles (NP) and the intensities increase with reaction time. UVvisible spectra suggest that [CTAB] and glutamic acid influence the morphology of the silver NP and act as shape-directing agents, whereas [Ag+] has no effect. The effects of the total [glutamic acid], [CTAB], and [Ag+] on the apparent rate constants of silver NP formation are determined. The sigmoidal curve of absorbance versus reaction time indicates an autocatalytic path involved in the growth process. The a-amino and ?COOH groups undergo chemical transformation (oxidative deamination and decarboxylation). The particles are spherical in shape with average diameters ranging between 12 and 25 nm, and their size distribution is wide. A plausible mechanism has been proposed with the following rate law: (d[silver sol])/dt = k[Ag+][Glutamic acid]T. (C) 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 680691, 2012