Synthesis of copper nanoparticles by reduction of Cu2+ ions to Cu-0 in the presence of cetyltrimethylammonium bromide (CTAB) and isopropanol (IPA). Experiments included the synthesis of copper nanoparticles by varying the molar concentration of CTAB keeping that of Cu2+ ions constant. In the first set Cu2+-IPA solution was added to CTAB-IPA mixture, the sequence was reversed in the second set. Differences in results are observed in each case. UV-visible spectra were recorded to note the changes taking place as a function of the added volume. Plasmon band for Cu-0 at similar to 560 nm and oligomers of Cu-0 at similar to 290 and similar to 340 nm wavelengths are observed. CTAB appears to play the role of catalyst in the reduction of Cu2+ ions in IPA under ambient conditions. Transmission electron microscopic (TEM) analysis of the copper nanoparticles synthesized at the two extreme molar ratios of Cu2+:CTAB, i.e. 1:0.25 and 1:30 show particles of size similar to 5-20 and similar to 2-10 nm, respectively, with a spherical morphology. (c) 2005 Elsevier B.V. All rights reserved.