Molecular-Level Investigation of Binary Fluid Droplets Impacting Surfaces

Droplets impacting with surfaces are commonly encountered processes in the field of protective coatings. The behavior of a colliding binary liquid droplet is sensitive to the impact velocity, surface wetting properties, and the droplet composition. Modeling molecular dynamics and classical density functional theory studies of impacting droplets as well as interfacial-surface free energies was reported on. The presence of two components in the liquid drop makes the surface collision a complicated problem. During the collision the kinetic energy of the drop is converted into heat. Thus, the temperature varies during the collision and throughout the droplet. Two extreme situations were captured by performing both adiabatic and isothermal simulations. Molecular dynamics and classical density functional theory were used to explore the effects of the mixing parameter on the phase diagram of the binary AB mixed droplets. The location of liquid-vapor and liquid-liquid phase separation was determined. In addition, the value of the interfacial tensions of all interfaces was computed. These can be used to predict when an A-rich and B-rich droplet will stay attached and when it will detach.