KnowHow team explains: The answer lies in the molecular and atomic level of the interface between the surfaces you are trying to make slide past each other and the lubricants.

Any resistance to slippage stems from the fact that the surfaces, even when polished, are not smooth, but have uneven elements resembling the contours of hills and valleys. The structures tend to interlock, like a pair of egg crates. The individual compartments of the egg crates could be as small as a molecule or an atom.

A lubricant has two basic functions ? one is to screen off the two surfaces from each other and the other is to provide a flow within the lubricant itself, allowing the surfaces to slide past each other.

The lubricant interacts with both the surfaces. Underlying this interaction are the shapes of the molecules and their electronic nature.

The ancients discovered that substances like animal fats and vegetables and mineral oils are good lubricants. What they didn’t know was that these substances had one thing in common: Molecules having a long chain of atoms. Each chain contains about 30 carbon atoms linked with each other. The chains are not aligned in parallel lines. The arrangement is quite random.

It’s now possible for scientists to design lubricant molecules for various needs, down to one or two layers.

The question was sent by

Ayan Banerjee via email