Silicon Nanotips and Related Nano-Systems Involving Fluid and Carrier Transport for Miniaturized Spacecraft Power and Sensing Applications

Ionic liquid ions sources (ILIS) extract ions from room temperature molten salts, or ionic liquids. Ion extraction is achieved by stressing the ionic liquid into a Taylor cone structure, formed on the apex of micro-sized, nanostructured tips known as emitters. These ion sources can be used in applications such as ILIS electrospray propulsion for multi-scale spacecraft and materials processing at the nanoscale. Through this research, the two fundamental life-limiting issues of ILIS operation have been identified and mitigated: electrochemical degradation and gas discharges. A distal electrode configuration was proposed and verified as a strategy to curtail electrochemistry. Furthermore, it was determined that trapped micro-bubbles of gas inside porous ILIS substrates can cause degassing during operation, leading to electrical discharges that provoke to device failure. It was demonstrated that discharges are suppressed through adequate liquid filling strategies. Lastly, novel fabrication techniques for emitter substrates and electrodes based on nanomaterials have been explored. Fabrication of porous dielectric substrates in micron-sized molds has been achieved by sintering of glass micro beads. In addition to strong student support (several graduate-level theses) and works published in the open literature, this research has facilitated continued collaboration with AFRL, AFOSR and other DoD agencies. Distribution A: Approved for public release. Distribution is unlimited