Tuning the Jet Speed and the Fiber Diameter in Near‐Field Electrospinning, a Parametric Study

Near‐field electrospinning (NFES) enables producing two‐ and three‐dimensional patterns and objects with submicrometric features by the controlled positioning of an electro‐hydrodynamically emitted fiber on a collector. To realize the high‐resolution potential of NFES, matching the jet arrival speed to the intended printing speed is essential. In this work, we use electrostatic jet deflection (EJD) to determine how the jet speed and characteristics of the collected fiber depend on the ink properties, ambient conditions, and processing parameters. We observe that the jet speed increases with higher applied voltages and lower nozzle‐to‐collector distances owing to the increase in electric field strength. It also increases with the ink’s electrical conductivity and preventing the drying of the drop. Slower jets are generated when using high‐viscosity inks or increasing the nozzle diameter, which promotes the ink drop drying at the nozzle exit. Fiber diameter is affected by the evaporation of the solvent on the drop surface, and it can be increased when raising the polymer concentration in the ink. Overall, we take advantage of the availability of EJD for determining the jet speed, enabling us to produce high‐resolution patterns by NFES while demonstrating different procedures to tune the jet speed and fiber diameter.