A simple method was demonstrated for synthesizing and isolating Au nanowires with a high density of twin boundary defects normal to the growth axis. In this process, oleylamine conveniently plays the role of the solvent, the reducing agent and the ligand. The geometry of the twin boundaries in the nanowires was in sharp contrast with the pentagonal twinning commonly observed in metal nanowires, and was of particular interest for its ultrahigh tensile strength. The nanostructure geometry and twin–twin average spacing were characterized using high-resolution electron microscopy, and the tensile strength of the nanowires was estimated in solution using a Ti ultrasound probe. A model was presented for explaining the role of the bulky ligand oleylamine in the formation of the twin boundaries that could be extended to include elastic terms in the ligand shell. The present work demonstrated that the use of bulky, asymmetrical ligands could induce extensive formation of twin boundary defects that in turn control the mechanical properties at the nanoscale.

Nanotwinned Gold Nanowires Obtained by Chemical Synthesis. M.Bernardi, S.N.Raja, S.K.Lim: Nanotechnology, 2010, 21[28], 285607