title: Defects at the Nanoscale Impact Contact Line Motion at all Scales.
abstract: The contact angle of a liquid drop moving on a real solid surface depends on the speed and direction of motion of the three-phase contact line. Many experiments have demonstrated that pinning on surface defects, thermal activation and viscous dissipation impact contact line dynamics, but so far, efforts have failed to disentangle the role of each of these dissipation channels. Here, we propose a unifying multiscale approach that provides a single quantitative framework. We use this approach to successfully account for the dynamics measured in a classic dip-coating experiment performed over an unprecedentedly wide range of velocity. We show that the full contact line dynamics up to the liquid film entrainment threshold can be parametrized by the size, amplitude and density of nanometer-scale defects. This leads us to reinterpret the contact angle hysteresis as a dynamical crossover rather than a depinning transition.
authors.affiliation: Physique et Mécanique des Milieux Hétérogènes, UMR 7636 ESPCI -CNRS, Université Paris-Diderot, 10 rue Vauquelin, 75005 Paris, France.
authors.forename: Hugo
authors.initials: H
authors.lastname: Perrin
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Université Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Lhermerout
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Université Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Kristina
authors.initials: K
authors.lastname: Davitt
authors.affiliation: Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Université Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Rolley
authors.affiliation: Physique et Mécanique des Milieux Hétérogènes, UMR 7636 ESPCI -CNRS, Université Paris-Diderot, 10 rue Vauquelin, 75005 Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Andreotti