Lattice boltzmann simulation of colloidal drop dynamics on patterned substrates for printable electronics fabrication

In this paper, the lattice Boltzmann method (LBM) is used for the direct numerical simulation of an inkjet-printed colloidal drop wetting on a patterned substrate. The single component multiphase (SCMP) model of Shan and Chen is used for the liquid-vapor multiphase flow and the particle suspension model is modified to incorporate adhesive forces between the suspended particle and the surrounding fluid phases. Several validation problems are presented to test the separate sub-models and the combined model. The combined multiphase particle suspension model is then used to study the contact angle hysteresis and the stick-slip behavior of the contact line motion as a liquid drop wetting and evaporating on a patterned substrate. Finally, the dynamics of a colloidal drop containing many suspended particles are examined with and without evaporation. Results show that colloidal jamming occurs at the liquid-vapor interface as the drop preferentially wets and evaporates on a patterned substrate. This model development is an important first step towards understanding the complex transport phenomena present in an inkjet-printed evaporating drop for printable electronics fabrication.