One-pot synthesis of long twin gold nanorods in a gelled surfactant solution

A new one-pot synthesis method was developed for producing long twin gold nanorods with lengths of ca. 1755 nm, which have the potential to be arranged on a substrate using anisotropic surface modification. This method was achieved by using citrate-stabilized seeds in a gelled surfactant solution, i.e., in the mixture of hexadecyltrimethylammonium bromide and octadecyltrimethylammonium bromide at low temperature (20 degrees C). The yield (ca. 60%) of this method is relatively high. The mechanism of the present growth conditions was compared with those reported in previous studies. As expected, NO3 had an influence on the length of the gold nanorods and the longest ones were obtained at an optimal concentration of NO3, even for growth in the gelled surfactant solution. In contrast, the number of seeds in the growth solution had no effect on the lengths of the nanorod grown in the gelled surfactant.