Séminaire de Mécanique d'Orsay

Le Jeudi 20 mars à 14h00 - Salle de conférences du FAST

Gradient dynamics description for thin films of complex fluids: a thermodynamic approach to the modelling of mixtures and suspensions.

Hender Lopez
School of Physics and Complex and Adaptive Systems Laboratory, University College Dublin, Ireland

Understanding the behaviour of thin layers of solutions and suspensions is of capital importance for several industrial process, as for e.g. in wet printing and coating were a solution is applied to a surface with the aim of producing a homogeneous or a structured layer of solute. One common way of describing the time evolution of these thin layer of a complex liquids is based on a hydrodynamical approach. Within this framework, partial differential equations that describe the time evolution of the film thickness and the concentration of solute are derive from the Navier-Stokes equations, the continuity equation, mass conservation laws and by employing a long-wave approximation. Recently we have proposed[1] an alternative way of deriving this equation which is based on thermodynamics instead of hydrodynamics. In this seminar we will review the gradient dynamics description of thin films of complex liquids. We will also show how this formulation allows the inclusion of new physical phenomena in a rather simple way compared to the "classical" hydrodynamical approach. Using this formulation we study the dewetting of thin films of liquids mixtures under the influence of concentration dependent wettability. Finally we discuss how to include evaporation in the model and use the obtained expressions to study the deposition process of evaporating suspensions.

[1] Thiele et al. Physical Review Letters 111, 117801 (2013)