The DMREF program at NCSU has demonstrated that hydroxylated nanodiamonds (+ND)  do not lubricate while carboxylated nanodiamonds (-ND) do lubricate at alumina-on-alumina and 304 stainless steel-on-steel interfaces. Studying the statistical correlations between physical properties and lubrication behaviors of nano-materials is revolutionizing the future of engineering and materials

Effective control of friction, wear and adhesion has a vast range of applications, including energy efficiency, national security, manufacturing, pharmaceuticals and the environment. Existing lubrication technologies were developed in an era that focused on wear elimination over energy losses from friction, with less consideration of environmental consequences. There is a pressing need for revolutionary new materials that would reduce friction and wear, and also eliminate the harsh environmental impacts of current materials. This DMREF project seeks to develop and test a new approach for rational design of materialliquid-nanoparticulate systems to achieve superior tribological performance. Theory, simulation, statistics, synthesis and characterization will be iteratively combined to develop design rules for controlling friction, adhesion and wear at material-liquid-nanoparticulate interfaces.

A combined QCM and AFM study has helped to propose an electrokinetic lubrication mechanism of negatively charged Silica nanoparticles. The majority of the nanoparticles is loosely bound to the surface and roll and/or slide on the surface while very few are rigidly adhered. The second layer of the nanoparticles constitutes the contact layer of the bulk liquid and slips on the top of surface layer while the repulsive forces between the individual nanoparticles provide for the observed lubrication effect.

This project is generously supported by the National Science Foundation.