Lubricant layer formation during the dip-coating process: influence of adsorption and viscous flow mechanisms

Thickness and structure of Z03, Z-Dol, Z-tetraol and AM2001 lubricant layers dip-coated on amorphous carbon surfaces were studied as a function of the dwell time in solution and the pull-out speed. The results demonstrate that the lubricant layer is formed via the joint action of surface adsorption and viscous flow mechanisms. Surface adsorption creates the bonded layer in the case of functionalized lubricants, whose thickness was found to be dependent on dwell time. The observed kinetics of the surface adsorption was described as a reversible second order process. The viscous flow mechanism is responsible for the formation of the mobile layer, whose thickness only depends on the pull-out speed.