Microfiber supported nanofiber membrane

• US 20060068668A1
• Filed: 10/28/2005
• Published: 03/30/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Kameoka, Jun, Nakano, Keiyo
• Granted Patent: US 7,591,883 B2
• Time in Patent Office: Days
• US Class Current: 442/340
• CPC Class Codes: B01D 2239/0225 Side-by-side
• CPC Class Codes: B01D 2239/0258 comprising nanoparticles
• CPC Class Codes: B01D 2239/0668 The layers being joined by heat or melt-bonding
• CPC Class Codes: B01D 2323/39 Electrospinning
• CPC Class Codes: B01D 39/163 sintered or bonded
• CPC Class Codes: B01D 67/0004 by agglomeration of particles
• CPC Class Codes: B01D 67/00042 by deposition of fibres, nanofibres or nanofibrils
• CPC Class Codes: B01D 69/10 Supported membranes; Membrane supports
• CPC Class Codes: B01D 69/108 Inorganic support material
• CPC Class Codes: B01D 71/40 Polymers of unsaturated acids or derivatives thereof, e.g. salts, amides, imides, nitriles, anhydrides, esters
• CPC Class Codes: B01D 71/4011 Polymethylmethacrylate
• CPC Class Codes: B01D 71/52 Polyethers
• CPC Class Codes: B01D 71/5211 Polyethylene glycol or polyethyleneoxide
• CPC Class Codes: B01D 71/72 Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of the groups B01D71/46 - B01D71/70 and B01D71/701 - B01D71/702
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: D01D 5/0069 characterised by the spinning section, e.g. capillary tube, protrusion or pin
• CPC Class Codes: D01D 5/0084 Coating by electro-spinning, i.e. the electro-spun fibres are not removed from the collecting device but remain integral with it, e.g. coating of prostheses
• CPC Class Codes: D01F 6/66 from polyethers
• CPC Class Codes: D01F 6/86 from polyetheresters
• CPC Class Codes: Y10S 264/48 Processes of making filters
• CPC Class Codes: Y10S 55/05 : Methods of making filter
• CPC Class Codes: Y10T 442/16 : Two or more nonwoven layers
• CPC Class Codes: Y10T 442/614 : Strand or fiber material specified as having microdimensions [i.e., microfiber]
• CPC Class Codes: Y10T 442/62 : Including another chemically different microfiber in a separate layer
• CPC Class Codes: Y10T 442/668 : Separate nonwoven fabric layers comprise chemically different strand or fiber material

Abstract

A nanofiber membrane is formed on a microfiber membrane. The nanofiber membrane may be electro sprayed directly onto the microfiber membrane and becomes integrated with the microfiber membrane to form a filter. The microfiber membrane provides structural integrity to for the nanofiber membrane, and an additional microfiber membrane may be added to sandwich the nanofiber membrane.

Claims

1. A method of forming a nanofiber filter, the method comprising:

positioning a microfiber filter and counter electrode a desired distance from a microfluidic emitter;

providing a polymer to the microfluidic emitter; and

applying a potential between the microfluidic emitter and the microfiber filter to electrospray nanofibers on the microfiber filter.

2. The method of claim 1 wherein at least a portion of the nanofibers are penetrating a surface of the microfiber filter.

3. The method of claim 2 wherein the desired distance is short enough such that the nanofibers are not dry when initially contacting the microfiber filter.

4. The method of claim 1 wherein the desired distance is between approximately 0.5 cm to 2.0.

5. The method of claim 1 wherein the applied potential is between 2000 V and 8500 V:

6. The method of claim 1 wherein the polymer is provided to the tip by dipping the tip in the polymer.

7. The method of claim 1 wherein the polymer is provided to the tip by an applicator.

8. The method of claim 1 wherein the polymer is selected from the group consisting of PEO, HDPC, and PMMA.

9. The method of claim 1 wherein the nanofibers are approximately between 100 to 200 nm in diameter.

10. The method of claim 1 wherein the nanofibers for a membrane approximately 20 nm to 1 um thick.

11. A filter comprising:

a first microfilter;

a nanofilter coupled to the first microfilter.

12. The filter of claim 11 wherein the nanofilter is adhered to the first microfilter.

13. The filter of claim 11 wherein portions of the nanofilter penetrates portions of the first microfilter.

14. The filter of claim 11, and further comprising a second microfilter positioned opposite the nanofilter from the first microfilter.

15. A filter comprising:

a first microfiber membrane;

a nanofiber membrane integrated at least partially into the first microfiber membrane.

16. The filter of claim 15 wherein the nanofiber membrane is spun thermally bonded to the microfiber membrane.

17. The filter of claim 15 and further comprising a second microfiber membrane coupled to the nanofiber membrane opposite the first microfiber membrane.

18. The filter of claim 15 and further comprising multiple further alternating layers of microfiber membranes and nanofiber membranes.

19. A method of forming a filter, the method comprising:

positioning a microfiber membrane and counter electrode a desired distance from a microfluidic emitter;

providing a nanofiber forming solution to the microfluidic emitter; and

applying a potential between the microfluidic emitter and the counter electrode to electrospray nanofibers on the microfiber membrane.

20. The method of claim 19 and further comprising adding a second microfiber membrane over the nanofibers.

21. The method of claim 19 and further comprising forming additional layers of nanofibers and microfiber membranes.

22. The method of claim 19 wherein the nanofibers form a membrane that is integrated into a portion of the microfiber membrane.

23. The method of claim 22 wherein the nanofiber membrane has an average pore size of less than approximately 100 nm².