  The present article reports the hitherto unreported phenomenon of arrested
evaporation dynamics in pendent droplets in an electric field ambience. The
evaporation kinetics of pendant droplets of electrically conducting saline
solutions in the presence of a transverse, alternating electric field is
investigated experimentally. It has been observed that while increase of field
strength arrests the evaporation, increment in field frequency has the opposite
effect. The same has been explained on the solvation kinetics of the ions in
the polar water. Theoretical analysis reveals that change in surface tension
and diffusion driven evaporation model cannot predict the arrested or
decelerated evaporation. With the aid of Particle Image Velocimetry,
suppression of internal circulation velocity within the droplet is observed
under electric field stimulus, and this affects the evaporation rate directly.
A mathematical scaling model is proposed to quantify the effects of
electrohydrodynamic circulation, electrothermal and electro-solutal advection
on the evaporation kinetics of the droplet. The analysis encompasses major
governing parameters, viz. the thermal and solutal Marangoni numbers, the
Electrohydrodynamic number, the electro Prandtl and electro Schmidt numbers and
their respective contributions. It has been shown that the electrothermal
Marangoni effect is supressed by the electric field, leading to deteriorated
evaporation rates. Additionally, the electrosolutal Marangoni effect further
supresses the internal advection, which again arrests the evaporation rate by a
larger proportion. Stability analysis reveals that the electric body force
retards the stable internal circulation within such droplets and arrests
advection.
