Drainage of a Wetting Liquid: Effective Slippage or Polymer Depletion?

Abstract

A surface force apparatus has been used to investigate the drainage of a viscosity improver lubricant. The characterization of the VI confined interface has been performed. Surprisingly, dynamical measurements enlighten a significant negative value of the immobile layer thickness. This result is discussed in terms of occurrence of slip at the wall, liquid–solid interface wettability, surface roughness and cleanliness, and friction experiments. Consequently, an interface molecular organization modelling is proposed based on polymer depletion near the solid–liquid interface.