Tribological properties of nanoparticle-laden ultrathin films formed by covalent molecular assembly.

The tribological properties of ultrathin films containing nanoparticles encapsulated in immobilized dendrimers are investigated. The films were formed by covalent molecular assembly in supercritical carbon dioxide, and the Au nanoparticles were formed in aqueous solution. End-capping of the terminal amine groups of the dendrimer by fluorinated species resulted in a reduction in the size of the nanoparticles formed. The resulting film structure displayed a lower coefficient of friction when the nanoparticles were formed after fluorination. The observed improvement in the tribological properties is attributed to the reduction in agglomeration of the nanoparticles due to the presence of the fluorine moieties.