An electrohydrodynamic spray apparatus includes a liquid inlet and a spray
nozzle in fluid communication with the liquid inlet, where the spray
nozzle has an opening downstream of the liquid inlet. An inner electrode
is situated at least partially inside the spray nozzle. An outer
electrode is situated external to the spray nozzle and within about 100
mm of the opening of the nozzle. The electrohydrodynamic spray apparatus
can be combined with a substrate to form an electrohydrodynamic spray
system. The electrohydrodynamic spray apparatus or system can be used to
form nanostructures such as nanodrops, nanoparticles and thin films.