Wettability and Structural Evolution of Gold over a Single-Walled Carbon Nanotube: An Atomistic Investigation

Gold nanostructures with high surface area-to-volume ratio
depict many applications for the design and development of advanced
materials for the nanoelectronic, catalyst, optoelectronic, antibacterial
properties, and so forth. For extensive applications, gold nanostructures
can be synthesized by the deposition over various substrates, such as
carbon nanotubes, graphite, silica, and so forth. In the present study, a thin
molten gold film has been deposited over a single-walled carbon nanotube
(SWCNT) to observe the wettability and phase transitions using
molecular dynamics simulation. At high temperature (T = 2000 K), the
gold film over a SWCNT depicts poor wettability and evolves into a
globule. However, during cooling from 2000 to 10 K, the gold globule
depicts phase transition from liquid to face-centered cubic crystalline
structure. At the interface between gold and SWCNT, gold atoms
organized both on- and off-positions over the hexagonal arrangement of
carbon atoms of SWCNT. In the case of on-position, the gold atom was positioned in the middle of the hexagonal arrangement
of carbon atoms. The off-position gold atom was situated just above the C−C bond of the SWCNT. Solvent-accessible surface areas (S), solid volume (V), dimensionless aspect ratio (κ = S3/V2), contact angle, adaptive common neighbor analysis, and radial density distribution function have been used for the analysis of wetting and structural evolution of gold over the SWCNT.
The present theoretical investigation will enhance our understanding related to the solid-state physical phenomena for the development of various types of metallic nanostructures.