An apparatus and method for improved control of low viscosity fluid flow
during electrohydrodynamic spray deposition of the fluid to coat small
targets, such as medical devices like stents. The apparatus includes a
target holder which applies a first electrical potential to a target, a
coating fluid transporter such as a wick, a siphon tube or a siphon tube
with a wick therein along which the coating fluid flows from a reservoir
to a dispensing end of the transporter, and an electrode which applied a
second electrical potential to the coating fluid sufficient to cause the
coating fluid to be attracted from the dispensing end of the transporter
toward the target. This provides a target coating apparatus with highly
self-regulating coating fluid flow characteristics despite the low
viscosity of the coating fluid, while producing highly consistent and
uniform target coatings.