Stick-slip Dynamics in the Forced Wetting of Polymer Brushes

Abstract

We study the static and dynamic wetting of adaptive substrates using a mesoscopic hydrodynamic model for a liquid droplet on a solid substrate covered by a polymer brush. First, we show that on the macroscale Young's law still holds for the equilibrium contact angle and that on the mesoscale a Neumann-type law governs the shape of the wetting ridge. Following an analytic and numeric assessment of the static profiles of droplet and wetting ridge, we examine the dynamics of the wetting ridge for a liquid meniscus that is advanced at constant speed. In other words, we consider an inverse Landau-Levich case where a brush-covered plate is introduced into (and not drawn from) a liquid bath. We find a characteristic stick-slip motion that emerges when the dynamic contact angle of the stationary moving meniscus decreases with increasing velocity, and relate the onset of slip to Gibbs' inequality and to a cross-over in relevant time scales.

References in corpus (13)

• Morphology changes in the evolution of liquid two-layer films
• Free surface flows with large slopes: beyond lubrication theory
• Relaxation of a dewetting contact line Part 1: A full-scale hydrodynamic calculation
• Gradient dynamics models for liquid films with soluble surfactant
• Modelling the formation of structured deposits at receding contact lines of evaporating solutions and suspensions
• Parameter passing between Molecular Dynamics and continuum models for droplets on solid substrates - The static case
• Morphological transitions of sliding drops: Dynamics and bifurcations
• Gradient-dynamics model for liquid drops on elastic substrates
• Non-Equilibrium Gibbs' Criterion for Completely Wetting Volatile Liquids
• Sessile drop evaporation in a gap -- crossover between diffusion-limited and phase transition-limited regime
• Non-equilibrium configurations of swelling polymer brush layers induced by spreading drops of weakly volatile oil
• Stick-Slip Contact Line Motion on Kelvin-Voigt Model Substrates
• Symmetry-breaking, motion and bistability of active drops through polarization-surface coupling

Cited by in corpus (7)

• Drops on polymer brushes -- advances in thin-film modelling of adaptive substrates
• Non-equilibrium configurations of swelling polymer brush layers induced by spreading drops of weakly volatile oil
• Dynamics of Droplets Moving on Lubricated Polymer Brushes
• Drops of volatile binary mixtures on brush-covered substrates
• Mesoscopic hydrodynamic model for spreading, sliding and coarsening compound drops
• Gradient dynamics model for drops of volatile liquid on a porous substrate
• What is active wetting?