Colloid thermophoresis in aqueous media is vital for numerous applications in nanoscience and life sciences. To date, a general description of colloid thermophoresis in DI water has not been determined....

The main aim of this study is to explore the role of viscoelastic properties of polymeric solutions on mode transitions in the electrospray process. By adjusting the applied electric potential between the nozzle and the collecting substrate, various electrohydrodynamic (EHD) modes were photographed by using a high-speed camera. Then, the effect of operating parameters on the droplet size in the dripping mode and the jet profile in the jet mode was investigated. By categorizing the EHD modes of each viscoelastic solution into dimensionless operating maps, it can be seen that by increasing the solution concentration, the extents of dripping mode and beads-on-a-string structure dwindle, while the jet stabilizes in a wider range of electric capillary numbers. Furthermore, contrary to deionized water, when the applied voltage escalates, the stick jet mode is observed where the jet sticks to the outer surface of the nozzle and the asymptotic thickness of the jet falls.

The purpose of this article is to explore the role of viscoelastic properties of polymeric solutions on the jet mode in the electrospray process. In this research, several numerical simulations were performed to model the behavior of electrified Newtonian and viscoelastic jets. First, used for validating viscoelastic constitutive equations and their implementation, the benchmark problem of the sedimenting sphere is stabilized beyond the previously suggested threshold. Then, an electrified DI water jet was simulated, and the obtained jet profile was compared with the experimental data from previous publications. Finally, the proposed algorithm was used to simulate viscoelastic electrified jets, where the effect of the Weissenberg number (Wi) on the jet profile was examined. In agreement with the previously obtained experimental results, by increasing the solution concentration, the asymptotic profile of the jet is reached at a smaller length from the nozzle, while the final thickness of the jet is slightly reduced.