Equillibrium distance between polycatenar ligand-coated metal nanoparticles.

Ligand-coated metal nanoparticles assembled into lattices are known to exhibit properties arising from their particulate organization, where interparticle distances play a key role. Precisely controlling these distances through organic ligands is a compelling approach for designing self-assembled functional materials. Although this technique has been frequently employed, studies involving extended aromatic ligands that induce large interparticle separations remain uncommon. This work focuses on calculating the interaction potentials between solvated polycatenar-functionalized gold nanoparticles by introducing an analytical model based on attractive van der Waals forces and ligand-driven repulsive steric interactions. The equilibrium distances are shown to mainly depend on the ligand length, the overlap of ligand shells, and the conformational angle of the ligands with respect to the nanoparticle surface. The calculated equilibrium distances are found to be in good agreement with experimental data obtained by analyzing Langmuir-Blodgett monolayer films.