NANO-FIBER ARRAYED SURFACES

• US 20080138577A1
• Filed: 08/01/2007
• Published: 06/12/2008
• Est. Priority Date: 08/07/2006
• Status: Active Grant

• Current Assignee: Paradigm Energy Research Corporation
• Original Assignee: Paradigm Energy Research Corporation
• Inventors: Sheehan, Daniel Peter
• Granted Patent: US 8,545,962 B2
• Time in Patent Office: Days
• US Class Current: 428/141
• CPC Class Codes: B81B 3/0075 For improving wear resistance
• CPC Class Codes: Y10T 428/24058 including grain, strips, or filamentary elements in respective layers or components in angular relation
• CPC Class Codes: Y10T 428/24124 Fibers
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]

Abstract

Surfaces are provided comprising an array of partially embedded nano-fibers. Two such surfaces may contact each other such that the respective nano-fibers contact at orthogonal angles, resulting in ultra-low friction and ultra-low adhesion contact. Such configurations are useful in several NEMS or MEMS applications, as well as macro-sized applications. Alternatively, the surfaces may contact each other such that the respective nano-fibers are parallel. These configurations are useful in micro-stage or high-order three- dimensional self assembly applications.

Claims

1. An apparatus, comprising:

a substrate comprising a surface; and

a plurality of nano-fibers partially embedded in the surface such that a portion of the embedded nano-fibers extend above the surface, wherein the nano-fibers are arranged such that their longitudinal dimension is substantially parallel to the surface.

2. The apparatus of claim 1, wherein the substrate is a rigid solid.

3. The apparatus of claim 1, wherein the substrate is a flexible solid.

4. The apparatus of claim 1, wherein the surface is locally flat with respect to the length of the nano-fiber.

5. The apparatus of claim 1, wherein the embedded nano-fibers are substantially parallel to each other.

6. The apparatus of claim 1, wherein the embedded nano-fibers are arranged in a concentric circular pattern.

7. The apparatus of claim 1, wherein the embedded nano-fibers are arranged in a radial pattern.

8. The apparatus of claim 1, wherein the nano-fibers are nanotubes.

9. The apparatus of claim 8, wherein the nanotubes are carbon nanotubes.

10. The apparatus of claim 9, wherein the carbon nanotubes are single-walled carbon nanotubes.

11. The apparatus of claim 9, wherein the carbon nanotubes are multi-walled carbon nanotubes.

12. The apparatus of claim 1, wherein the embedded nano-fibers are positioned within trenches in the surface of the substrate.

13. The apparatus of claim 12, wherein the trenches have an approximately rectangular cross section.

14. The apparatus of claim 12, wherein the trenches have an approximately semi-circular cross section.

15. A system, comprising:

a first member having a first surface, wherein a first set of nano-fibers are partially embedded in the first surface such that a portion of the first set of nano-fibers extend above the first surface, wherein the first set of nano-fibers are arranged such that their longitudinal dimension is substantially parallel to the first surface; and

a second member having a second surface, wherein a second set of nano-fibers are partially embedded in the second surface such that a portion of the second set of nano-fibers extend above the second surface, wherein the second set of nano-fibers are arranged such that their longitudinal dimension is substantially parallel to the second surface.

16. The system of claim 15, wherein the first set of nano-fibers contacts the second set of nano-fibers at an angle.

17. The system of claim 16, wherein the angle is from about 200 to about 90°

.

18. The system of claim 16, wherein the angle is from about 45°

to about 90°

.

19. The system of claim 16, wherein the angle is about 90°

.

20. The system of claim 16, wherein the first set of nano-fibers are substantially parallel to each other and the second set of nano-fibers are substantially parallel to each other.

21. The system of claim 20, comprising a first voltage source electrically connected to the first set of nano-fibers and a second voltage source electrically connected to the second set of nano-fibers.

22. The system of claim 16, wherein the first set of nano-fibers are arranged in a concentric circular pattern and the second set of nano-fibers are arranged in a radial pattern.

23. The system of claim 15, wherein the first set of nano-fibers are substantially parallel to each other and the second set of nano-fibers are substantially parallel to each other and the first set of nano-fibers contacts the second set of nano-fibers in a substantially parallel configuration.

24. The system of claim 23, comprising a mechanical actuator coupled to the first member, wherein the mechanical actuator is configured to move the first member laterally relative to the second member from a first position where a first nano-fiber in said first set of nano-fibers contacts a second nano-fiber in said second set of nano-fibers, to a second position where the first nano-fiber contacts a third nano-fiber in said second set of nano-fibers.

25. A nano-electromechanical system (NEMS) or micro-electromechanical system (MEMS), comprising:

a first member configured to move from a first position to a second position upon application of an electric field, the first member comprising a first surface, wherein a first set of nano-fibers are partially embedded in the first surface such that a portion of the first set of nano-fibers extend above the first surface, wherein the first set of nano-fibers are arranged such that their longitudinal dimension is substantially parallel to the first surface and to each other; and

a second member comprising a second surface, wherein a second set of nano-fibers are partially embedded in the second surface such that a portion of the second set of nano-fibers extend above the second surface, wherein the second set of nano-fibers are arranged such that their longitudinal dimension is substantially parallel to the second surface and to each other, wherein when the first member is in said second position, the first set of nano-fibers contact the second set of nano-fibers at an angle.

26. The NEMS or MEMS of claim 25, wherein the first and second sets of nano-fibers are carbon nanotubes.

27. The NEMS or MEMS of claim 25, wherein the first member is a cantilever.

28. The NEMS or MEMS of claim 27, wherein the NEMS or MEMS is a switch.

29. The NEMS or MEMS of claim 27, wherein the NEMS or MEMS is a motor.

30. A self-assembled structure, comprising a plurality of three-dimensional members, each member comprising at least one surface comprising a plurality of nano-fibers partially embedded therein such that a portion of the nano-fibers extend above the surface in which they are embedded, wherein the nano-fibers are arranged such that their longitudinal dimension is substantially parallel to the surface in which they are embedded and substantially parallel to other nano-fibers embedded in the same surface, wherein at least one nano-fiber-embedded surface contacts another nano-fiber-embedded surface such that the respective nano-fibers are substantially parallel to each other.

31. A method of moving an object across a first surface, the method comprising:

placing a first substrate on the first surface, wherein the first substrate comprises a second surface facing away from the first surface, wherein a first set of nano-fibers are partially embedded in the second surface such that a portion of the first set of nano-fibers extend above the second surface, wherein the first set of nano-fibers are arranged such that their longitudinal dimension is substantially parallel to the second surface and to each other;

placing a second substrate on the first substrate, wherein the first substrate comprises a third surface facing towards the second surface and a fourth surface facing away from the first and second surfaces, wherein a second set of nano-fibers are partially embedded in the third surface such that a portion of the second set of nano-fibers extend above the third surface, wherein the second set of nano-fibers are arranged such that their longitudinal dimension is substantially parallel to the third surface and to each other, wherein the second set of nano-fibers contact the first set of nano-fibers at an angle;

placing the object on the fourth surface; and

moving the second substrate laterally relative to the first substrate.

32. A method of manufacturing a low-friction surface, the method comprising placing a plurality of nano-fibers in a corresponding plurality of trenches formed in a surface.

33. The method of claim 32, wherein the trenches are formed by removing material from the substrate using electron beam lithography.

34. The method of claim 32, wherein the trenches are formed using molecular beam epitaxy.

35. The method of claim 32, wherein placing the nano-fibers in the trenches comprises:

placing the nano-fibers in a liquid;

depositing the liquid onto the substrate; and

evaporating the liquid.

36. The method of claim 32, wherein placing the nano-fibers in the trenches comprises vibrating the substrate.

37. The method of claim 32, wherein placing the nano-fibers in the trenches comprises reacting chemical species on the nano-fibers with chemical species in the trenches.

38. The method of claim 32, further comprising removing nano-fibers from the substrate that are not fully seated in a trench.

39. The method of claim 38, wherein the removing comprises exposing the substrate to a gas jet.

40. The method of claim 38, wherein the removing comprises applying an adhesive to the substrate and then subsequently removing the adhesive.

41. The method of claim 38, wherein the removing comprises applying ultrasonic energy to the substrate.

42. The method of claim 38, comprising repeating the placing and removing steps one or more times.

43. The method of claim 32, wherein the length of each trench is approximately the same as the length of the nano-fibers.

44. The method of claim 32, wherein the trenches are arranged into columns, each column comprising a plurality of co-axial trenches having approximately the same length.

45. The method of claim 44, wherein the trenches in adjacent columns are offset such that the ends of each trench in one column are not aligned with the ends of trenches in an adjacent column.