Shape-directing role of cetyltrimethylammonium bromide in the green synthesis of Ag-nanoparticles using Neem (Azadirachta indica) leaf extract

The shape-directing role of cetyltrimethylammonium bromide, CTAB, is reported to the green synthesis of Ag-nanoparticles for the first time using Neem (Azadirachta indica) leaf extract. UV-vis spectroscopy, transmission electron microscopy (TEM), and selected area electron diffraction (SAED) patterns were used to monitor the growth kinetics, morphology and crystalline nature of Ag-nanoparticles, respectively. It was observed that the growths of Ag-nanoparticles are stopped within 40 min of reaction time. The Ag-nanoparticles are polydispersed spherical and exhibiting an interesting triangle, flat, plate-like hexagonal and some irregular morphology in presence of different [CTAB]. Hexagonal particles aggregated in a systematic manor, leads to produce a fine tiles-like arrangement of Ag-nanoparticles with dimensions between 10 and 37 nm. The nature of reaction-time curves to the reduction of Ag+ ions by Neem leaf extract are much different than those observed by us in our earlier studies using different bio-reductants. (C) 2012 Elsevier B.V. All rights reserved.