| Tue January 28th 2014 14:00 ZH286 | Seminar | Dynamic unbinding transitions and deposition patterns in dragged meniscus problems Uwe Thiele |
Details:We study the transfer of a film or patterned deposit onto a flat plate that is extracted from a bath of pure liquid or solution/suspension. After introducing problems related to deposition patterns [1] we first address the case of a pure non-volatile liquid and review some previous works [2,3]. Employing a long-wave hydrodynamic model, that incorporates wettability via a Derjaguin (disjoining) pressure, we analyse steady-state meniscus profiles as the plate velocity is changed. We identify four qualitatively different dynamic transitions between microscopic and macroscopic coatings that are out-of-equilibrium equivalents of equilibriumunbinding transitions [4]. Next, we discuss a gradient dynamics formulation that allows us to systematically extend the one-component model used above into thermodynamically consistent two-component models [5] as used, e.g., to describe the formation of line patterns during the Langmuir-Blodgett transfer of a surfactant layer from a bath onto a moving plate [6]. Recently, we developed a reduced Cahn-Hilliard-type model to analyse the bifurcation structure of this deposition process [7]. We sketch this rather involved structure and discuss how the time-periodic solutions related to line deposition emerge through various local and global bifurcations. [1] U. Thiele, Adv. Colloid Interface Sci., at press, 2014, doi:10.1016/j.cis.2013.11.002; [2] A. O. Parry et al., Phys. Rev. Lett. 108:246101, 2012. [3] J. Ziegler, J. H. Snoeijer, J. Eggers. Eur. Phys. J.-Spec. Top. 166:177-180, 2009. [4] M. Galvagno et al., arxiv.org/abs/1311.6994; http://arxiv.org/abs/1307.4618 [5] U. Thiele, A. J. Archer and M. Plapp, Phys. Fluids 24, 102107 (2012). [6] M. H. Kopf, S. V. Gurevich, R. Friedrich, and L. F. Chi, Langmuir 26, 10444-10447 (2010). [7] M. H. Kopf, S. V. Gurevich, R. Friedrich and U. Thiele, New J. Phys. 14, 023016 (2012). | ||
