Anti-stiction ionic lubricants in MEMS devices
In examples, a microelectromechanical device comprises a moveable element configured to contact a portion of a surface, and an ionic liquid on the portion of the surface.
1 . A microelectromechanical systems (MEMS) device comprising:
a mirror configured to tilt in a first direction to contact a first spring tip at a first portion of a surface and tilt in a second direction to contact a second spring tip at a second portion of the surface, wherein the mirror comprises aluminum and the spring tip comprises aluminum; and
a film on the first and second portions of the surface, in which the film is a result of an ionic fluid having been heated and having reacted with one or more chemical groups of the first and second portions.
2 . The device of claim 1 , wherein the film is a monolayer film having a thickness of from about 1 nm to less than about 50 nm.
3 . The device of claim 2 , wherein the film exhibits a contact angle of equal to or greater than 80 degrees as determined in accordance with ASTM D5946.
4 . The device of claim 1 , wherein the film is a multilayer film comprising a plurality of layers n, wherein n ranges from 2 to 5 and wherein each layer has a thickness of from about 1 nm to less than about 50 nm.
5 . The device of claim 1 , wherein the ionic liquid has a vapor pressure of from about 1×10 −12 torr to about 1×10 −2 torr.
6 . The device of claim 1 , wherein the ionic liquid has a boiling point of from about 200° C. to about 600° C.
7 . The device of claim 1 , wherein the ionic liquid comprises a cation characterized by a general formula YR n , wherein Y is an onium ion; R is a substituted alkyl group, an unsubstituted alkyl group or a combination thereof; and n ranges from 1 to 6.
8 . The device of claim 7 , wherein the cation comprises an imidazolium ion, a phosphonium ion, an ammonium ion, a pyrrolidinium ion, or a combination thereof.
9 . The device of claim 1 , wherein the ionic liquid comprises an anion characterized by a general formula QZ n , wherein Q is phosphorus, sulfur, or boron; Z is a halide, oxygen, alkoxy group, haloalkyl group or a combination thereof; and n ranges from 1 to 6.
10 . The device of claim 9 , wherein the anion comprises tetrafluoroborate, hexafluorophosphate, phosphate, perfluoroalkyl phosphate, bis(trifluoromethanesulfonyl)amide, or a combination thereof.
11 . A method, comprising:
contacting first and second portions of one or more surfaces of a micromechanical systems (MEMS) device with an ionic liquid,
wherein the ionic liquid comprises a cation characterized by a general formula YR n , wherein Y is an onium ion and R is a substituted alkyl group, an unsubstituted alkyl group or a combination thereof and n ranges from 1 to 6, and wherein the ionic liquid comprises an anion characterized by a general formula QZ n , wherein Q is phosphorus, sulfur, or boron and Z is a halide, oxygen, alkoxy group, haloalkyl or combination thereof and n ranges from 1 to 6;
activating the ionic liquid by heating the ionic liquid to a temperature between about 25° C. to about 200° C., wherein, in response to being activated, the ionic liquid is configured to react with one or more chemical groups of the first and second portions of the one or more surfaces to form a film on the first and second portions of the one or more surfaces; and
sealing the MEMS device after activating the ionic liquid to form the film.
12 . The method of claim 11 , wherein the one or more chemical groups comprise hydroxyl groups or hydroxyl precursor groups.
13 . The method of claim 11 , wherein the contacting comprises deposition, chemical vapor deposition, dip coating, aerosol coating, spray coating, or any combination thereof.
14 . The method of claim 11 , wherein the film is a monolayer having a thickness of from about 1 nm to less than about 50 nm.
15 . The method of claim 11 , wherein the film is a multilayer film having n layers wherein n ranges from 2 to about 5 and each layer has a thickness of from about 1 nm to less than about 50 nm.
16 . The method of claim 11 , wherein the film exhibits a contact angle of equal to or greater than 80 degrees as determined in accordance with ASTM D5946.
17 . A microelectromechanical device comprising:
a moveable element configured to contact a first portion of a surface and a second portion of the surface; and
a film on the first and second portions of the surface, in which the film is a result of an ionic liquid on the first and second portions of the surface having been heated and having reacted with one or more chemical groups of the first and second portions, wherein the ionic liquid is characterized by a cation having any of Structures I or II, wherein R is an alkyl group.
18 . The device of claim 17 , wherein the film has a thickness of from about 1 nm to less than about 50 nm.
19 . The device of claim 18 , wherein the film exhibits a contact angle of equal to or greater than 80 degrees as determined in accordance with ASTM D5946.