Controlled assembly of gold nanorods on nanopatterned surfaces: Effects of surface materials, pH and surfactant.

In a controlled assembly of gold nanorods (GNRs) into surface patterns the important factors are surface properties of the GNRs and the substrate as well as the immobilization time. Influence of chemical and physical interactions on assembly of positively charged, hexadecyltrimethylammonium bromide (CTAB) stabilized GNRs on silicon wafer and indium tin oxide (ITO) substrate surfaces were studied. The substrates were silanized with mercaptosilane to provide thiol groups for chemical bonding of nanorods. Effect of pH of the GNR solution was examined in assembly of nanorods using electrostatic and morphologic interactions. By using a higher pH and ITO surface, we have demonstrated that the controlled assembly of the GNRs can be guided with ring and line patterns fabricated by electron beam lithography.