Molecular Dynamics Study of Temperature Influence on Directional Motion of Gold Nanoparticle on Nanocone Surface

In
this work, the
directional motion and underlying mechanism of a circular gold nanoparticle
(AuNP) on nanocone (NC) surface were studied with the aid of molecular
dynamics simulation. Three specific sized AuNP(s) having particular
number of atoms and three nanocones having distinct apex angle were
utilized in this work. The simulation was run in a temperature range
of 300–1300 K to observe the effect of temperature on the directional
motion of AuNP located outside of NC surface. The results revealed
that the AuNP tends to move toward the larger-diameter direction of
the NC at higher temperature range, whereas it stayed intact on the
area around the tip of NC at lower temperature range. It was observed
that the average velocity of AuNP located outside the NC surface with
large apex angle was comparatively lower than that on the NC surface
having small apex angle. Furthermore, it was inspected that the interaction
energy of the AuNP is reduced heavily as the temperature is increased,
and it decayed more in the large diameter AuNP, which resulted in
higher velocity of large-diameter AuNP on the NC surface. Moreover,
the contact angle of AuNP on a flat silicon surface is observed. It
was found that the AuNP stayed intact at low temperature, but it started
to deform at higher temperature due to its transition from unmolten
(solid) to molten (liquid) state. In addition, the melting temperature
of AuNP is also measured by analyzing the potential energy results
at different temperatures during the simulation.