Deposited droplet size histogram obtained from different eletrospraying modes.

<p>Four eletrospraying modes were analyzed: (A) micro-dripping mode at electric field of 1.3 kV/cm, (B) spindle mode at electric field of 1.4 kV/cm, (C) cone-jet mode at electric field of 1.5 kV/cm, and (D) precession mode at electric field of 1.6 kV/cm. The optical microscopy images of the deposited droplets are shown in the inset Figs with scale bars of 100 μm.