Investigation of Frictional Properties in Pure and Mixed Fluorocarbon/Hydrocarbon Monolayers by Molecular Simulations

Abstract

Due to small surface area to volume ratios, nanoscale devices can exhibit dominant surface forces that can quickly degrade un-lubricated contacting surfaces. While fluorinated materials have been widely used as lubricants and are more stable than their hydrocarbon counterparts against elevated temperature and humidity, they are known to exhibit higher frictional forces. To overcome this issue, here we study the concept of mixed monolayers composed of both hydrocarbon and fluorocarbon chains. Hydrocarbon-based monolayers have been widely studied and shown to improve frictional properties and device life. To investigate the frictional behavior of mixed fluorocarbon/hydrocarbon monolayers, molecular dynamics simulations of pure hydrogenated and fluorinated chains and mixed fluorinated/hydrogenated chains on silica surfaces and tips have been performed.