Patent ID: 8551576

Claim:
A method for controlling a coefficient of friction, comprising: providing a plurality of nanoparticles on a surface; moving the surface having the plurality of nanoparticles thereon; applying a force to the plurality of nanoparticles on the moving surface, the force being selected from a magnetic force, an electro-magnetic force, an electrostatic force, and combinations thereof; and controlling a rolling-to-sliding ratio of the plurality of nanoparticles on the moving surface by i) adjusting a value of the force applied to the plurality of nanoparticles relative to a value of tangential forces applied to achieve relative motion of the surface upon which the nanoparticles are provided, and ii) adjusting a direction of the force applied to the plurality of nanoparticles relative to a direction of tangential forces applied to achieve relative motion of the surface upon which the nanoparticles are provided.