Gold nanorod can reshape:
Surface gold atoms are considerably more mobile than bulk ones. Surface diffusion leads to shape changes in gold nanoparticles, even at temperatures much lower than 1064°C, the melting temperature of bulk gold. This phenomenon is called reshaping. Gold nanorods reshape into the thermodynamically more stable spherical shape, possibly with facets. While at room temperature gold nanorods in solution can be stable for several months to years, at a temperature of 250 °C rods reshape into spheres within 1 h. During reshaping, the shape of the rod remains close to a spherically capped cylinder, and the particle aspect ratio can be deduced from the longitudinal plasmon wavelength, as for non-heated rods.
Ref. “On the temperature stability of gold nanorods: comparison between thermal and ultrafast laser-induced heating,” Phys. Chem. Chem. Phys. 8, 814–821 (2006)
Surface gold atoms are considerably more mobile than bulk ones. Surface diffusion leads to shape changes in gold nanoparticles, even at temperatures much lower than 1064°C, the melting temperature of bulk gold. This phenomenon is called reshaping. Gold nanorods reshape into the thermodynamically more stable spherical shape, possibly with facets. While at room temperature gold nanorods in solution can be stable for several months to years, at a temperature of 250 °C rods reshape into spheres within 1 h. During reshaping, the shape of the rod remains close to a spherically capped cylinder, and the particle aspect ratio can be deduced from the longitudinal plasmon wavelength, as for non-heated rods.
Ref. “On the temperature stability of gold nanorods: comparison between thermal and ultrafast laser-induced heating,” Phys. Chem. Chem. Phys. 8, 814–821 (2006)