Numerical Simulation of Colloidal Drop Deposition Dynamics on Patterned Substrates for Printable Electronics Fabrication

One of the major challenges in printable electronics fabrication is the print resolution and accuracy for high precision applications such as printable displays. 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 for confined deposition. The two-dimensional multiphase particle suspension LBM model previously developed by the authors is extended to three-dimensional with the addition of the particle rotational dynamics and an improved treatment of particle-particle forces. The model is 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.