Electrospray/electrospinning apparatus and method

• US 20050224998A1
• Filed: 04/08/2004
• Published: 10/13/2005
• Est. Priority Date: 04/08/2004
• Status: Active Grant

• Current Assignee: Research Triangle Institute
• Original Assignee: Research Triangle Institute
• Inventors: Ensor, David S., Andrady, Anthony L.
• Granted Patent: US 7,762,801 B2
• Time in Patent Office: Days
• US Class Current: 264/10
• CPC Class Codes: D01D 5/0069 characterised by the spinning section, e.g. capillary tube, protrusion or pin
• CPC Class Codes: D01D 5/0092 characterised by the electrical field, e.g. combined with a magnetic fields, using biased or alternating fields

Abstract

Apparatus and method for producing fibrous materials in which the apparatus includes an enclosure having an inlet configured to receive a substance from which the fibrous materials are to be composed, a common electrode disposed in the enclosure, and plural extrusion elements provided in a wall of the enclosure opposite the common electrode so as to define between the plural extrusion elements and the common electrode a space in communication with the inlet to receive the substance in the space. In the method, a substance from which the fibrous materials are to be composed is fed to the enclosure having the plural extrusion elements, a common electric field is applied to the extrusion elements in a direction in which the substance is to be extruded, the substance is extruded through the extrusion elements to tips of the extrusion elements, and the substance is electrosprayed from the tips to form the fibrous materials.

Claims

1. An apparatus for producing fibrous materials, comprising:

an enclosure having an inlet configured to receive a substance from which the fibrous materials are to be composed;

a common electrode disposed in said enclosure; and

plural extrusion elements provided in a wall of the enclosure opposite the common electrode so as to define between the plural extrusion elements and the common electrode a space in communication with said inlet to receive said substance in said space.

2. The apparatus of claim 1, wherein said plural extrusion elements comprise an array of said extrusion elements.

3. The apparatus of claim 1, wherein said common electrode is located equidistant from said plural extrusion elements.

4. The apparatus of claim 1, further comprising:

an exterior electrode located outside the enclosure such that upon application of a voltage across that common and exterior electrodes an electric field is produced extending from said common electrode through said wall and to said exterior electrode.

5. The apparatus of claim 4, wherein said exterior electrode is configured to collect said fibrous materials.

6. The apparatus of claim 4, further comprising:

a collecting mechanism disposed between the enclosure and the exterior electrode and configured to collect said fibrous materials.

7. The apparatus of claim 4, wherein said exterior electrode comprises at least one of a plate and a screen.

8. The apparatus of claim 4, wherein said exterior electrode comprises an electrical ground.

9. The apparatus of claim 4, wherein said exterior electrode is disposed 1-50 cm from said common electrode.

10. The apparatus of claim 4, further comprising:

a power source electrically connected across said common electrode and said exterior electrode to generate said electric field.

11. The apparatus of claim 10, wherein said power source is configured to generate said electric field with a strength of 2,000-400,000 V/m.

12. The apparatus of claim 1, wherein said plural extrusion elements comprise plural openings through said enclosure.

13. The apparatus of claim 12, wherein said openings have an inner dimension in a range of 50-250 μ

m.

14. The apparatus of claim 1, wherein said plural extrusion elements comprise tubes.

15. The apparatus of claim 14, wherein said tube has an interior cross sectional area of 1900-50,000 μ

m².

16. The apparatus of claim 14, wherein said tube has an outer dimension of less than 400 μ

m.

17. The apparatus of claim 1, wherein said plural extrusion elements comprise:

a plurality of solid elements placed against each other to define extrusion channels between said plurality of solid elements.

18. The apparatus of claim 1, wherein said plural extrusion elements define 2-100 openings in the wall of the enclosure.

19. The apparatus of claim 1, wherein said plural extrusion elements comprise at least one of capillaries, frits, needles, and foams.

20. The apparatus of claim 1, wherein at least one of said plural extrusion elements extends past an outer surface of said enclosure.

21. The apparatus of claim 1, wherein at least one of said plural extrusion elements comprises a metallic member.

22. The apparatus of claim 1, wherein at least one of said plural extrusion elements comprises an insulating member.

23. The apparatus of claim 1, wherein the common electrode has a flat surface facing said plural extrusion elements.

24. The apparatus of claim 1, wherein the common electrode comprises:

protrusions extending toward said plural extrusion elements.

25. The apparatus of claim 1, wherein the common electrode comprises:

a flat surface having a peripheral rim facing said extrusion elements.

26. The apparatus of claim 1, wherein the common electrode is centered in said enclosure.

27. The apparatus of claim 1, wherein said wall comprises an electrically permeable material.

28. The apparatus of claim 27, wherein said electrically permeable material comprises an insulator.

29. The apparatus of claim 27, wherein said electrically permeable material comprises a frit.

30. The apparatus of claim 27, wherein said electrically permeable material comprises silicon.

31. The apparatus of claim 1, further comprising:

a chamber enclosing at least said enclosure.

32. The apparatus of claim 1, further comprising:

a shroud enclosing at least said enclosure.

33. An apparatus for producing fibrous materials, comprising:

an enclosure configured to hold a substance from which the fibrous materials are to be extruded;

a common electrode located within the enclosure; and

means for electrospraying said substance from said enclosure at plural positions, said means for electrospraying facing the common electrode.

34. The apparatus of claim 33, wherein said means for electrospraying electrospins fibers from said substance.

35. The apparatus of claim 33, wherein said means for electrospraying electrospins nanofibers from said substance.

36. The apparatus of claim 33, further comprising:

means for collecting said fibrous materials from said means for electrospraying.

37. The apparatus of claim 33, wherein said means for electrospraying electrospins fibers from said substance in an electric field having a strength of 2,000-400,000 V/m.

38. A method for producing fibrous materials, comprising:

feeding a substance from which the fibrous materials are to be composed to an enclosure having plural extrusion elements;

applying a common electric field to said plural extrusion elements in a direction in which said substance is to be extruded;

extruding said substance through said plural extrusion elements to tips of the extrusion elements; and

electrospraying said substance at the tips of said plural extrusion elements to form said fibrous materials.

39. The method of claim 38, wherein said electrospraying comprises:

electrospinning said extruded substance from said plural extrusion elements to form fibers.

40. The method of claim 38, wherein said electrospraying comprises:

electrospinning said extruded substance from said plural extrusion elements to form nanofibers.

41. The method of claim 38, wherein said electrospraying comprises:

electrospinning said fibrous materials in said common electric field having a strength of 2,000-400,000 V/m.

42. The method of claim 38, further comprising:

collecting said fibrous materials on a collector.

43. The method of claim 42, wherein said collecting comprises:

collecting fibers of said extruded substance.

44. The method of claim 38, wherein the electrospraying comprises:

electrospinning polymeric fibers.

45. The method of claim 44, further comprising:

annealing said polymeric fibers to form carbon fibers.

46. The method of claim 38, wherein the electrospraying comprises:

electrospinning polymeric nanofibers.

47. The method of claim 46, further comprising:

annealing said polymeric nanofibers to form carbon nanofibers.