Solvation structure and dynamics for passivated Au nanoparticle in supercritical CO2: A molecular dynamic simulation

All-atomic molecular dynamics simulations have been performed to study the interfacial structural and dynamical properties of passivated gold nanoparticles in supercritical carbon dioxide (scCO2). Simulations were conducted for a 55-atom gold nanocore with thiolated perfluoropolyether as the packing ligands. The effect of solvent density and surface coverage on the structural and dynamical properties of the self-assembly monolayer (SAM) has been discussed. The simulation results demonstrate that the interface between nanoparticle and scCO2 solvent shows a depletion region due to the preclusion of SAM. The presence of scCO2 solvent around the passivated Au nanoparticle can lead to an enhanced extension of the surface SAM. Under full coverage, the structure and conformation of SAM are insensitive to the density change of scCO2 fluid. This simulation results clarify the microscopic solvation mechanism of passivated nanoparticles in supercritical fluid medium and is expected to be helpful in understanding the scCO2-based nanoparticle dispersion behavior.

Molecular simulations have been performed to study the interfacial structural and dynamical properties of gold nanoparticles, passivated by thiolated perfluoropolyether, in supercritical carbon dioxide.Figure optionsDownload high-quality image (134 K)Download as PowerPoint slideResearch highlights
► The solvation behavior of passivated gold nanoparticles in supercritical carbon dioxide was simulated.
► The presence of scCO2 solvent around the nanoparticle can lead to an enhanced extension of the surface self-assembly monolayer.
► The effect of solvent density and surface coverage on the structures and properties of the self-assembly monolayer has been discussed.