Orientation and position of cylindrical-shaped gold nanoparticles at liquid-liquid interfaces

The equilibrium orientation and position of cylindrical-shaped gold nanoparticles (GNPs) at an oil/water interface is studied by varying its geometry and surface property and the oil/water interfacial tension. Numerical calculation reveals that most of the particles studied prefer one of two states of orientation at the interface: either 0° or 90° irrespective of the geometry, the surface property, and the oil/water interfacial tension. In the case of cylindrical-shaped GNPs having a weakly hydrophobic side surface, an increase in oil/water interfacial tension leads to a remarkable change in the orientation and position of the particles depending on the geometry.