Article originally published on Noria.com.
Friction modifiers and mild anti-wear agents are polar molecules added to lubricants for the purpose of minimizing light surface contacts (sliding and rolling) that may occur in a given machine design. These are also called boundary lubrication additives.
Esters, natural and synthetic fatty acids as well as some solid materials such as graphite and molybdenum disulfide are used for these purposes. These molecules have a polar end (head) and an oil-soluble end (tail). Once placed into service, the polar end of the molecule finds a metal surface and attaches itself. If you could see the orientation of the molecules on the surface, it would appear something like the fibers of a carpet, with each molecule stacked vertically beside the others.
(read the entire article, "What are Friction Modifiers?" at Noria.com...)
