Modulation of Nanoparticle Diffusion by Surface Ligand Length and Charge: Analysis with Molecular Dynamics...

Area of Science:

• Physical Chemistry
• Materials Science
• Nanotechnology

Background:

• Interpreting nanoparticle size measurements requires understanding diffusion influenced by surface ligands.
• Nanoparticle diffusion is affected by physical and chemical ligand properties.

Purpose of the Study:

• To investigate how ligand charge and flexibility impact the diffusion of gold nanoparticles.
• To clarify discrepancies in nanoparticle size measurements from experimental techniques.

Main Methods:

• Explicit solvent molecular dynamics simulations were employed.
• Simulations probed the diffusion of gold nanoparticles with varying surface ligands.

Main Results:

• Cationic nanoparticles showed only a modest decrease in diffusion constants compared to hydrophobic ones.
• Increasing ligand length had a limited effect on diffusion.
• Discrepancies in experimental nanoparticle size measurements were attributed to aggregation.

Conclusions:

• Electrostatic friction's impact on highly charged nanoparticle diffusion is limited by the anticorrelation with van der Waals forces.
• Including solvent molecules in simulations minimally affects diffusion dynamics but reduces relaxation time disparities.