fig4

Figure 4. EHD process parameter optimization and representative printed pattern examples. Process parameter optimization of (A) voltage; (B) working height (nozzle-substrate distance); (C) printing speed (nozzle moving speed) and (D) number of printed layers; (E) Microscopic characterization of high-precision lines printed by EHD; (F) Representative EGaIn-AgNPs patterns printed with optimized parameters; (G) Demonstration of EGaIn-AgNPs pattern conformality, attached to sample bottles, round tubes, wavy patterns, and rectangular corners; (H) EGaIn-AgNPs pattern attached to the center of the palm, which can withstand shrinking, compression, stretching, and pinching; (I) EGaIn-AgNPs pattern attached to plant surfaces such as leaves, petals and stems. EHD: Electrohydrodynamic; EGaIn-AgNPs: eutectic gallium indium-silver nanoparticles.