Transport of Ionic Liquid Across Emitter Die due to Surface Tension
This video shows the transport of ionic liquids across the surface of a monolithically batch-fabricated planar array of externally fed electrospray emitters. The emitters are coated with black silicon, i.e., a nanostructured conformal layer that enhances their wettability. A droplet of the ionic liquid is placed on top of the die, outside the field of view of the video. One can readily see the wetting front of ionic liquid advancing as the video progresses. The video is focused on an emitter whose appearance changes from dull (light is reflected by the black silicon coating) to shinny (light is reflected with the ionic liquid on top of the emitter). The emitter has vertical sidewalls; therefore, the liquid transport due to surface tensin effects is not influenced by gravity.