  This work provides a complete rheological characterization of 2D-inks in
electric fields with different intensities and orientations to the imposed flow
field. 2D nanomaterials used in this study are graphene nanoplatelets,
hexagonal boron-nitride, and molybdenum disulfide. These materials with
different electric properties are dispersed in a non-polar solvent (Toluene)
with different concentrations of Ethyl Cellulose (EC), providing Newtonian or
viscoelastic characteristics. Shear rheology tests show that the presence of
nanoparticles barely changes the fluid behavior from the carrier fluid, and the
application of an electric field perpendicular to the flow does not result in
electrorheological behavior. However, extensional experiments, which mimic the
actual EHD jet printing conditions, allowed the observation of the influence of
both the particles and the electric field aligned on the filament thinning
process. It was observed that the electric field generates vortices due to an
electrophoretic effect in the carrier fluid when EC is present in the
formulations, which has severe consequences on the stability of the liquid
bridges, whereas it scarcely affects the shear viscosity; additionally, the
kind of 2D nanoparticles modifies also the conductivity and permittivity of the
solution, inducing Maxwell stresses that also make the filament more stable
against surface tension.
