Abstract: A tribo-system includes a metal substrate having a surfactant layer chemisorbed to a side thereof, a lubricant established on the metal substrate, and a plurality of nanoparticles dispersed in the lubricant. Each of the nanoparticles includes i) an inorganic core having a predetermined size and shape, and ii) a surfactant shell chemisorbed to a surface of the inorganic core, where the surfactant shell has a predetermined thickness. The adhesive force and energy between the metal substrate surface and the nanoparticles is higher than the adhesive force and energy between individual particles of the nanoparticles.

Abstract: A method for controlling a coefficient of friction involves applying a magnetic force, an electro-magnetic force, and/or an electrostatic force to nanoparticles disposed on a surface. The method further involves controlling a rolling-to-sliding ratio of the nanoparticles on the surface by i) adjusting a value of the force applied to the nanoparticles, and/or ii) adjusting an orientation of the nanoparticles by adjusting a direction of the force applied to the nanoparticles.

Abstract: A method for controlling a coefficient of friction involves applying a magnetic force, an electro-magnetic force, and/or an electrostatic force to nanoparticles disposed on a surface. The method further involves controlling a rolling-to-sliding ratio of the nanoparticles on the surface by i) adjusting a value of the force applied to the nanoparticles, and/or ii) adjusting an orientation of the nanoparticles by adjusting a direction of the force applied to the nanoparticles.

Abstract: A tribo-system includes a metal substrate having a surfactant layer chemisorbed to a side thereof, a lubricant established on the metal substrate, and a plurality of nanoparticles dispersed in the lubricant. Each of the nanoparticles includes i) an inorganic core having a predetermined size and shape, and ii) a surfactant shell chemisorbed to a surface of the inorganic core, where the surfactant shell has a predetermined thickness. The adhesive force and energy between the metal substrate surface and the nanoparticles is higher than the adhesive force and energy between individual particles of the nanoparticles.

Abstract: A surface forces measuring apparatus (SFA) including miniature rheometers and friction measuring devices. Both static (i.e., equilibrium) forces and dynamic (e.g., time-dependent such as viscous, hysteretic and frictional) forces can be measured between two surfaces in relative motion to each other along the z-direction (normally) or the x- or y-directions (horizontally), or along any desired direction in 3D space. The new instrument uses a novel combination of piezoelectric tubes and N-type bimorphs, and a three-stage mechanical mechanism to produce linear motion of one of the surfaces along any desired direction, and a combination of an optical technique and semi-conductor strain-gauges allows for the force produced on the other surface to be directly measured, also in any direction (which may be in a different direction from that of the first surface which generates the force).