Stick-slip dynamics in the forced wetting of polymer brushes

Greve, Daniel; Hartmann, Simon; Thiele, Uwe

Research article (journal)

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 mean 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.

Details zur Publikation

Release year: 2023
Language in which the publication is written: English
Link to the full text: https://arxiv.org/abs/2301.10513