  This study provides a complete rheological characterization of 2D
nanomaterial dispersions, employed as 2D-inks precursors in printed
electronics. Three different 2D nanomaterials (molybdenum disulfide (MoS2),
graphene, and hexagonal boron nitride(hBN)) were dispersed in a Newtonian fluid
(toluene) and a viscoelastic fluid (toluene + ethyl cellulose) with different
polymer concentrations. The presence of nanoparticles does not change the shear
rheology of the carrier fluid. Regarding the extensional rheology, the results
showed that the pinch-off phenomenon is present in all Toluene suspensions;
however, the presence of the ethyl cellulose introduces elasticity in the
system, even leading to the formation of beads-on-a-string, and the relaxation
times of the suspensions depends on the kind of nanoparticles present in the
fluid. As controlling the droplet size when dispensing 2D-inks is of paramount
importance for printed electronics, as well as for many other applications,
here it is presented a correlation between the rheological properties of these
2D-inks precursors and their droplet size when generated from a capillary
nozzle in dripping regime.
