  We study both numerically and experimentally the breakup of a viscoelastic
liquid bridge between two parallel electrodes. We solve the leaky-dielectric
FENE-P model to describe the dynamical response of the liquid bridge under
isothermal conditions. The results show that the surface charge screens the
inner electric field perpendicular to the free surface over the entire
dynamical process. The liquid bridge deformation produces a normal electric
field on the outer side of the free surface that is commensurate with the axial
one. The surface conduction does not significantly affect the current intensity
in the time interval analyzed in the experiments. The force due to the shear
electric stress becomes comparable to both the viscoelastic and surface tension
forces in the last stage of the filament. However, it does not alter the
elasto-capillary balance in the filament. The extensional relaxation times
approximately coincides with the stress relaxation time prescribed in the
FENE-P model. We measure experimentally the filament electrical conductivity
and extensional relaxation time for PEO dissolved in deionized water and in a
mixture of water and glycerine. We compare the filament electrical conductivity
with the value measured in hydrostatic conditions for the same estimated
temperature. Good agreement was found for PEO dissolved in water+glycerine,
which indicates that the change of the filament microscopic structure due to
the presence of stretched polymeric chains does not significantly alter the ion
mobility in the stretching direction. Significant deviations are found for PEO
dissolved in deionized water that may be attributed to the heat transferred to
the ambient, neglected in the calculation of the filament temperature. The
extensional relaxation time measured from the images acquired during the
filament thinning hardly depends on the applied voltage.
