Method and apparatus for a porous electrospray emitter

Patent metadata

Field	Value
Publication number	US-10685808-B2
Application number	US-201916511067-A
Country	US
Kind code	B2
Filing date	Jul 15, 2019
Priority date	May 6, 2008
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

An ionic liquid ion source can include a microfabricated body including a base and a tip. The body can be formed of a porous material compatible with at least one of an ionic liquid or room-temperature molten salt. The body can have a pore size gradient that decreases from the base of the body to the tip of the body, such that the at least one of an ionic liquid or room-temperature molten salt is capable of being transported through capillarity from the base to the tip.

First claim

What is claimed is:

1. A method of forming an electrospray emitter comprising:
pouring a gel solution into a mold shaped to form one or more emitter bodies with a base and a tip; and
drying the gel solution in the mold to form the one or more emitter bodies at least partially from a porous material.

2. The method of claim 1 , wherein the gel solution is a sol gel solution.

3. The method of claim 2 , wherein the sol gel solution includes a solvent, an acidic aluminum salt, a polymer, and a proton scavenger.

4. The method of claim 2 , further comprising mixing aluminum chloride hexahydrate, polyethylene oxide, water, ethanol, and propylene oxide to form the sol gel solution.

5. The method of claim 1 , wherein the porous material is a ceramic.

6. The method of claim 1 , wherein the porous material is alumina.

7. The method of claim 1 , further comprising treating and/or processing the tip of each emitter body such that a pore size of the one or more emitter bodies decreases from the base to the tip of the one or more emitter bodies.

8. The method of claim 1 , wherein the gel solution has a composition such that resulting pores of the porous material have a diameter between or equal to 3 μm and 5 μm.

9. The method of claim 1 , wherein the mold is shaped to form a tip of the one or more emitter bodies with a radius of curvature between or equal to 1 μm and 20 μm.

10. The method of claim 1 , further comprising electrochemically etching the one or more emitter bodies to form tips having a radius of curvature of between or equal to 1 μm and 20 μm.

11. A method of forming an electrospray emitter comprising:
pouring a slurry including ground porous material into a mold shaped to form one or more emitter bodies with a base and a tip;
freezing the slurry in the mold to form a frozen slurry; and
drying the frozen slurry to form the one or more porous emitter bodies.

12. The method of claim 11 , wherein drying the frozen slurry includes freeze-drying the frozen slurry.

13. The method of claim 11 , wherein the ground porous material is a ground porous ceramic.

14. The method of claim 11 , further comprising sintering the one or more emitter bodies.

15. The method of claim 11 , wherein freezing the slurry further comprises freezing the slurry in the mold with a temperature gradient such that a temperature of the slurry increases in a direction from the tip of the one or more emitter bodies toward the base of the one or more emitter bodies.

16. The method of claim 15 , wherein freezing the slurry with the temperature gradient results in a pore size of the one or more emitter bodies decreasing from the base to the tip of the one or more emitter bodies.

17. The method of claim 11 , further comprising treating and/or processing the tip of each emitter body such that a pore size of the one or more emitter bodies decreases from the base to the tip of the one or more emitter bodies.

18. The system of claim 11 , wherein the slurry has a composition such that resulting pores of the one or more porous emitter bodies have a diameter between or equal to 3 μm and 5 μm.

19. The system of claim 11 , wherein the mold is shaped to form a tip of the one or more emitter bodies with a radius of curvature between or equal to 1 μm and 20 μm.

20. The method of claim 11 , further comprising grinding a porous material to form the ground porous material.

Assignees

• Massachusetts Inst Technology

Inventors

• Lozano Paulo C
• Arestie Steven Mark

Classifications

• H01J49/0445

  with means for introducing as a spray, a jet or an aerosol (electrospray ion sources H01J49/165) · CPC title

• H01J2237/317

  Processing objects on a microscale · CPC title

• H01J1/05

  characterised by material · CPC title

• C25F3/14

  locally · CPC title

• H01J2237/0802

  Field ionization sources · CPC title