On the Spraying Modality of Liquids by Pyroelectrohydrodynamics

We present for the first time an investigation on the spraying modality for the pyroelectrohydrodynamic (pyro-EHD) system. We show that the pyro-EHD spray (p-Spray) works well in the range from far field (d > 10 mm) to near field (d < 2 mm) without the need of external voltage and without the needs to change the experimental apparatus in that wide range of distances. Because the proposed method works without a counter electrode, no limitations are connected with the geometric shape of the substrate on which the spray coating is deposited. We report on several examples of the formation of disperse sprayed droplets, whose size can be varied between hundreds of micrometers and hundreds of nanometers, as well as on the production of sprayed pattern footpaths. The results reported here demonstrate the direct writing of spray patterns of nano/microdroplets with different materials in a very wide range, that is, from low- to high-viscous liquid solutions. Finally, as an example of application, we show the use of the p-Spray for the fabrication of silver-coated devices showing antimicrobial properties of the pattern produced by the p-Spray through a customizable and environmental friendly approach.