Surprisingly, under the same colloidal conditions (i.e, [PVP10K] 0.1-10 mg/mL, [CTAC] 0.04-0.08 mM, [Au 0 ] 5 mM) the assembly and printing of AuNRs in aqueous solution was not observed, even when [Au 0 ] was increased to 15 mM. It is well known that increased curvature of the gold nanoparticle surface results in less dense coverage of surfactant, i.e, the density of grafted ligands is greater on the faces of gold nanorods than in gold nanospheres . In the previous study, it was noted that an "excess" in the concentration of surfactant (around 0.1 mM CTAC in the case of AuNS) inhibited the formation of assemblies by preventing the surface adsorption by PVP. This suggests that the higher CTAC density on the surfaces of rods may inhibit their assembly in aqueous solutions.