Molecular dynamics modelling of water nanodroplet impingement on silicon dioxide and silicon nitride substrates

This paper reports the study of a droplet-based scalable micro/nanomanufacturing process using molecular dynamics (MD) modelling. The objective of the study is to understand the nanodroplet impingement and spreading mechanism on silicon dioxide (SiO 2 ) and silicon nitride (Si 3 N 4 ) substrates with different impingement velocities. The dependence of dynamic contact angle on the initial droplet velocity was investigated for hydrophilic and hydrophobic substrate interactions. Higher rebound effect and thereby slower wetting rates were observed for the SiO 2 -water system as compared to the Si 3 N 4 -water system for the same magnitudes of impingement velocities. The MD simulation results were validated using the molecular kinetic theory. Findings of this research are expected to establish the required process controls in droplet-based scalable nanomanufacturing for precision deposition of nanoscale features.