Optimizing wettability of externally wetted microfabricated silicon electrospray thrusters

Electrospray propulsion devices with externally wetted architectures have shown favorable performance. The design of microfabricated silicon thrusters and their feed systems requires an understanding of propellant flow over a silicon surface. This research explores the parameters that affect wettability of externally wetted microfabricated silicon electrospray thruster arrays and how varied wetting surface treatments affect thruster performance. Silicon samples with various black silicon treatments were fabricated and optimal black silicon etch parameters were determined by measuring the samples wettability. Silicon wettability was analyzed by producing samples with various black silicon treatments and then measuring contact angle, measuring surface roughness, imaging surface geometry, calculating spreading rates, and performing treated thruster current output tests. Two propellants, 1-ethyl-3-methyl-imidazolium tetraflouroborate (EMI-BF4) and 1-ethyl-3-methyl-imidazolium bis(triflouromethyl-sulfonyl)amide (EMI-IM), were used in contact angle measurements and spreading rate experiments. A model describing the spread of a small drop of EMI-BF4 and EMI-IM over roughened silicon substrates is presented.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Garza, Tanya Cruz

Advisor dc:contributor.advisor

• Manuel Martínez-Sánchez.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/38648

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/38648