DROP-ON-DEMAND INKJET PRINTING ASSESSMENT OF GRAPHENE FROM AQUEOUS GRAPHENE DISPERSIONS

Efforts on precise fabrication of micro- and nanoscale devices have led to the necessity of good control over the features of device components. Drop-on-demand inkjet printing (IJP) is a contactless method which enables maskless deposition and patterning of components of three-dimensional systems, sensors, and polymer composites, to name a few. Dispersions of nanoparticles are among the liquid precursors used in delivering the material to be deposited, in droplet form, onto the desired substrate. In this work, we have evaluated the printability of graphene nanofluids of 0.05-0.15% nanoparticle volume fraction by considering temperature-dependent experimental viscosity and surface tension data from the literature. The printability assessment is typically performed using dimensionless numbers, including Reynolds number, Weber number, and Ohnesorge number corresponding to certain drop formation and printability regimes. Results revealed that the considered Graphene-H2O nanofluids can be printed using a drop-on-demand inkjet printer with 25 mu m nozzle diameter and at 5-10 m/s drop velocity. In this case, although the droplets have sufficient formation energy, they are in the satellite droplet regime whose trajectories are mostly challenging to be predicted. As such, IJP of these nanofluids require the recently introduced satellite droplet printing method which uses a gas steam to transport satellite droplets with precise positioning. Results of this work may potentially shed a light on fabrication of graphene-based bioelectronics and bio-MEMS via drop-on-demand IJP.