In this report, fabrication process using two-photon polymerization lithography is demonstrated for capillary emitters used in ionic liquid electrospray thruster. Launches of nanosatellites is a recent trend in field of space, due to time and cost saving. While their size and weight limit thruster installation, a new type of electric propulsion thruster called ionic liquid electrospray thruster (ILEST) is attracting attention. In ILEST, ionic liquid is used as a propellant and is fed on to the tip of an emitter and electrosprayed. Emitters are fabricated in an array to get sufficient thrust. Capillary emitter has a capillary and can passively supply ionic liquid to the tip by capillary force, and experiments have shown that the smaller the capillary diameter is, the better the specific impulse become. This work used two-photon polymerization lithography. This technology fabricates high aspect ratio and complex structures with negative photoresist. As a result, capillary emitters with a height and base diameter of 10 μm and a capillary diameter of 2 μm were fabricated with a good uniformity in capillary dimensions.
OZASA et al. (Wed,) studied this question.