Micro-electro-mechanical device with ion exchange polymer

Abstract

A micro-electro-mechanical device includes an ion exchange polymer coated onto a surface or within pores of a micro-electro-mechanical portion. The micro-electro-mechanical device may be an electrode, a sensor or a cantilever. The ion exchange polymer may comprise an additive, such as an inorganic particle or powder or a metal-organic framework compound. Gases may react with the ionomer and create voltage and/or current which can be measured. The incorporation of ion exchange polymer with a MEM to produce electrode can provide interesting chemical, mechanical and electrical properties, which may have promise in sensor application and some other applications. The ion exchange polymer may be either cation exchange polymer or anion exchange polymer. The ion exchange polymer can be chemically cross-linked, or reinforced by support material or additive.

Claims

1. A micro-electro-mechanical device comprising: a) micro-electro-mechanical portion; b) an ion exchange polymer coated onto the micro-electro-mechanical portion; wherein the MEMS portion has a length of between a hundred nanometers to about 990 microns.

2. The micro-electro-mechanical device of claim 1, wherein the ion exchange polymer is a cation exchange polymer.

3. The micro-electro-mechanical device of claim 2, wherein the ion exchange polymer is a perfluorinated sulfonic acid polymer.

4. The micro-electro-mechanical device of claim 1, wherein the ion exchange polymer is an anion exchange polymer.

5. The micro-electro-mechanical device of claim 4, wherein the anion exchange polymer is crosslinked.

6. The micro-electro-mechanical device of claim 4, wherein the ion exchange polymer is a quaternary ammonium-tethered poly(biphenyl alkylene).

7. The micro-electro-mechanical v of claim 1, further comprising an additive within the ion exchange polymer.

8. The micro-electro-mechanical device of claim 1, wherein the additive is an inorganic filler.

9. The micro-electro-mechanical device of claim 8, wherein the inorganic filler is selected from the group consisting of: silica, alumina, zirconia, titania, cerium oxide, boron oxide, and zirconium phosphate.

10. The micro-electro-mechanical v of claim 7, wherein the additive is a metal-organic compound (MOF).

11. The micro-electro-mechanical device of claim 1, wherein the ion exchange polymer is reinforced by support material.

12. The micro-electro-mechanical device of claim 1, wherein the support material is a porous support material and wherein at least a portion of the ion exchange polymer is configured within the support material.

13. The micro-electro-mechanical device of claim 12, wherein the support material comprises an expanded polytetrafluoroethylene membrane.

14. The micro-electro-mechanical device of claim 13, wherein the expanded polytetrafluoroethylene membrane has a thickness of no more than 1 micron.

15. The micro-electro-mechanical device of claim 1, wherein the micro-electro-mechanical device forms a portion of a sensor.

16. The micro-electro-mechanical device of claim 1, wherein the micro-electro-mechanical device is an electrode.

17. The micro-electro-mechanical device of claim 1, wherein the micro-electro-mechanical device is a cantilever.

18. A micro-electro-mechanical device comprising: a) micro-electro-mechanical portion; b) a metal-organic compound coated onto the micro-electro-mechanical portion.

19. The micro-electro-mechanical device of claim 18, further comprising an ionomer coupled between the micro-electro-mechanical portion and the metal-organic compound.

20. The micro-electro-mechanical device of claim 18, wherein the micro-electro-mechanical device is a cantilever.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0026] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.

[0027] FIG. 1 shows an exemplary embodiment of a MEM device comprising an ion exchange polymer coated on the surface.

[0028] FIG. 2 shows an exemplary embodiment of a MEM device comprising an ion exchange polymer coated in the porous material of the MEM device and on the surface.

[0029] FIG. 3 shows an exemplary embodiment of a MEM device comprising an ion exchange polymer coated onto a MEM device.

[0030] Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0031] As used herein, the terms comprises, comprising, includes, including, has, having or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of a or an are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0032] Certain exemplary embodiments of the present invention are described herein and are illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications, improvements are within the scope of the present invention.

[0033] As shown in FIG. 1, an exemplary MEM device 10 comprises an ion exchange polymer coated on the surfaces of a MEM portion 30. A first ion exchange polymer 22 is coated onto the first surface 20 and a second ion exchange polymer 42 is coated on a second surface. The first and second ion exchange polymers may be the same or different types of ion exchange polymer. Note that the ion exchange polymer may be coated onto only a single side of the MEM portion, such as on the first side only. An additive 52 may be configured in the ionomer, or ion exchange polymer 22 on the first side and a second additive 54 may be configured in the ionomer on the second side, or the second ion exchange polymer 42. The first and second additives may be the same or different materials and may include, but are not limited to including, silica, alumina, zirconia, titania, cerium oxide, boron oxide, zirconium phosphate, metal hydride or metal organic framework material.

[0034] As shown in FIG. 2, an exemplary MEM device 10 comprises an ion exchange polymer coated on the surfaces of a MEM portion 30 as well as in the pores 32 or porous portion of the MEM portion. A MEM portion may comprise pores proximal the first surface 20 or second surface 40 or through the thickness, as shown. A first ion exchange polymer 22 may be coated onto the first surface 20 and into pores of extending from the first surface and a second v 42 may be coated on a second surface and into the pores extending from the second surface. The first and second ion exchange polymers may be the same or different types of ion exchange polymer, such as different ionomers, on an anion exchange polymer on a first side and a cation exchange polymer on a second side. Note that the ion exchange polymer may be coated onto only a single side of the MEM portion, such as on the first side and into any pores extending from the first side. A first additive 52 may be configured in the ionomer, or ion exchange polymer 22 on the first side and a second additive 54 may be configured in the ionomer on the second side, or the second ion exchange polymer 42. A third additive 53 may be incorporated into the ionomer that is within the pores of the MEM portion. The first, second and third additives may be the same or different materials and may include, but is not limited to including, silica, alumina, zirconia, titania, cerium oxide, boron oxide, zirconium phosphate, metal hydride or metal organic framework material.

[0035] The MEM portion shown in FIGS. 1 and 2 may be a cantilever 18 portion that is deflects when an ionic species is absorbed or adsorbed by the ion exchange polymer. This deflection or movement of the cantilevered MEM portion may be detected through any number of ways to provide a sensor for the species absorbed or adsorbed by the ion exchange polymer. For example, carbon dioxide may be absorbed into the depth of the Ion exchange polymer and cause the cantilever to deflect. The specific ion exchange polymer may be chosen to cause a target gas or compound to absorb into the ion exchange polymer or adsorb onto the surface of the ion exchange polymer.

[0036] The MEM devices shown in FIGS. 1 and 2 may be a sensor 14, or an electrode 16. Leads may be coupled to the MEM device to measure voltage and or current or some other sensor or monitoring component may be coupled with the MEM device to measure electrical properties and/or mechanical changes, such as deflection, strain and the like.

[0037] As shown in FIG. 3, a MEM device 10 is a cantilever 18 having a fixed end 37 and a cantilevered end 35. The MEM device has a plurality of teeth 39 that extend to a first surface 20. The tips of the teeth comprise an ion exchange polymer 22 which may have an additive 52. The second surface 40 of the MEM device may have an ion exchange polymer 42 having a second side additive 54. The type of ionomer and additive may be selected to achieve a high deflection of the cantilevered MEM when exposed to various gases, for example. Furthermore, Metal-organic-frameworks (MOFs), may be coated onto or into a portion of the MEM device along with an ionomer as a binder or directly onto or into the MEM device. The MEM portion has a length from the fixed end to the extended end which may be from a hundred or more nanometers to about 990 microns.

[0038] As shown in FIGS. 1 to 3, a MEM device may comprise a support material 24, 44 on the first or second surface, respectively. The support material may be porous having pores 25 for receiving ionomer and/or additives therein. As described herein, an exemplary support material may be a very thin porous membrane, such as an ePTFE membrane having a thickness of no more than 1 micron. The ionomer and/or MOF material may be coated onto or into the support material. The additives may be configured on or within the pores of the support material. In an exemplary embodiment, an ionomer with additives is coated onto a support material, such as an ePTFE membrane, and the ionomer wicks into the pores but the additives are retained on the surface of the ePTFE membrane as the particle size is larger than the pore or pore openings of the ePTFE membrane. This produces a high concentration of additives on the surface of the support material and a gradient through the thickness of the composite coated MEM portion.

[0039] It will be apparent to those skilled in the art that various modifications, combinations and variations can be made in the present invention without departing from the spirit or scope of the invention. Specific embodiments, features and elements described herein may be modified, and/or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents.