**2.4.3 Nozzle diameter**

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trajectory of thin jet under an electric-field, and jet disintegrate into droplets and cause spray

If the applied voltage is further increased, the cone becomes smaller and smaller. With increasing the applied voltage, second jet emerges from the cone. With further increase in applied voltage, more and more jet emerges from the cone, this mode is called multi-jet

The parameters that influence the formation and transition of stable cone-jet mode can be divided in two groups. Operating parameters i.e. flow-rate, electric field and nozzle diameter, and liquid properties i.e. electric conductivity, viscosity and surface tension (Poon,

The flow-rate has a significant effect on the jet diameter and stability of the jet in cone-jet transition. It is the main parameters to control the jet diameter for the patterning process. The flow-rate also affects the applied potential requirement for development of cone-jet (operating envelop) and the resulting the shape of the cone-jet. In electrohydrodynamic jetting, flow-rate also affect the stability of the jet, at low flow-rate the jet is stable, whereas the high flow-rate in cone-jet region destabilize the jet resulting in shorter jet length. This is due to amount of charge carrying at high flow-rate which destabilizes the jet. The typical

Fig. 3. Effect of flow rate on the cone-jet transition, as shown the jet diameter increases with

Electric field affects the morphology of the cone, by increasing the electric field strength in steady cone-jet mode, the cone-jet recedes towards the nozzle. However, there is less effect on the jet diameter by increasing the applied voltage. At relatively low flow-rate and high electric field, the jet disintegrated into mist of small droplets also known as electrospray

effects of the flow-rate on stable cone-jet mode are shown in figure 3.

increase in flow-rate. The red arrow indicates the jet break-up point.

**2.4.2 Electric field (applied voltage)** 

due to electrostatic repulsive forces between themselves.

**2.4 Parameters affecting the cone-jet** 

**2.3 Multi-jet mode** 

mode.

2002).

**2.4.1 Flow-rate** 

Nozzle diameter has significant influence on the operating envelope of the stable cone-jet region. Smaller nozzle diameters extend the lower and higher value of flow-rate limit. The voltage requirement for the cone-jet also decreases with decrease in nozzle diameter for any given liquid.
