Electrohydrodynamic pulsed-inkjet characteristics of various inks containing aluminum particles

As nano-sized silver particles are prohibitively expensive, lower cost materials (e.g., micro-sized aluminum) are sought for the manufacture of conducting electrodes. Inks containing various aluminum weight percentages are dot-printed onto a stainless-steel substrate with an electrohydrodynamic (EHD) inkjet, which is superior to thermal and piezoelectric inkjets for inks containing larger particles because it ejects drops smaller than the nozzle diameter. Various ink solvents (ethanol, octanol, and diethylene glycol) are formulated with aluminum particles from 1 to 10 wt%. EHD inkjet characteristics such as drop-separation distance, drop size, drop-to-substrate impact velocity, and required voltage are reported. The ink's thermo-fluid properties are the primary factors controlling drop characteristics and printing quality. ► Electrohydrodynamics (EHD) inkjet printing technology had been explored for potential use in printed electronics. ► Various inks, ethanol, octanol, and DEG, containing 1–10 wt% aluminum particles were studied. ► The voltage required for drop generation also depends on the fluid's viscosity and surface tension. ► Increased aluminum concentrations in the ethanol ink required increased voltages for drop generation. ► For the range of 1–10 wt% considered in this study, particle concentration did not significantly affect the jetting characteristics.