Frictional effects in solute-solvent interactions: Researchers developed an empirical procedure to study friction using atoms as solutes instead of molecules

摘要

Interest in a better understanding of how friction occurs on the microscopic scale is necessary to enable us to better deal with the real-world lubrication problems we encounter on the macroscopic scale. In a previous TLT article, the concept of molecular friction in solution was described. This phenomenon is an important consideration because most lubricants are liquids that contain a basestock or solvent such as mineral oil and additives that can be designated as solutes. The previous work done by professors Stephen Bradforth, Richard Stratt and co-workers was to evaluate the formation of a cyano radical in solution. In this research, the cyano radical rotated over an unexpectedly long time frame. The researchers felt that solvent molecules would rush in more quickly to dissipate the energy of rotation. But the rapid rotation of the cyano radicals generated a bubble around them because they were able to quickly push away some of the nearby solvent atoms. Eventually, rotation of the cyano radicals declined and the solvent molecules rush back. Then the physical bumping of the solvent molecules into the cyano radical slows down the rotation in a manner analogous to molecular friction.