COMPLIANT BASE TO INCREASE CONTACT FOR MICRO- OR NANO-FIBERS

• US 20100062208A1
• Filed: 11/17/2006
• Published: 03/11/2010
• Est. Priority Date: 11/18/2005
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Jones, Steven D., Groff, Richard E., Fearing, Ronald S., Majidi, Carmel
• Granted Patent: US 7,709,087 B2
• Time in Patent Office: Days
• US Class Current: 428/91
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C09J 2301/31 the adhesive effect being based on a Gecko structure
• CPC Class Codes: C09J 7/00 Adhesives in the form of films or foils
• CPC Class Codes: Y10S 977/724 Devices having flexible or movable element
• CPC Class Codes: Y10S 977/762 Nanowire or quantum wire, i.e. axially elongated structure having two dimensions of 100 nm or less
• CPC Class Codes: Y10T 428/2395 Nap type surface
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2915 including textile, cloth or fabric
• CPC Class Codes: Y10T 428/2929 Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• CPC Class Codes: Y10T 428/298 Physical dimension

Abstract

A fabricated microstructure includes a substrate, a primary fiber, and a plurality of base fibers. The primary fiber has a width less than about 5 microns. Each base fiber of the plurality of base fibers has a first end attached to the primary fiber and a second end attached to the substrate. Each base fiber has a width less than the width of the primary fiber.

Claims

1. A fabricated microstructure, comprising:

a substrate;

a primary fiber having a width less than about 5 microns; and

a plurality of base fibers, each base fiber having a first end attached to the primary fiber and a second end attached to the substrate, wherein each base fiber has a width less than the width of the primary fiber.

2. The fabricated microstructure of claim 1, wherein the plurality of base fibers is formed as an array attached to the primary fiber.

3. The fabricated microstructure of claim 1, wherein the width of the primary fiber is about ten times larger than the width of each one of the base fibers.

4. The fabricated microstructure of claim 1, wherein the plurality of base fibers and the primary fiber are formed from the same material.

5. The fabricated microstructure of claim 1, wherein the plurality of base fibers permits compliance of the primary fiber.

6. The fabricated microstructure of claim 1, wherein the plurality of base fibers are formed as a first double-cantilever structure, wherein the first double-cantilever structure comprises two parallel sides separated by a gap, and wherein the first double-cantilever structure permits compliance of the primary fiber in a first direction perpendicular to the two parallel sides of the first double-cantilever structure.

7. The fabricated microstructure of claim 6, further comprising:

a second double-cantilever structure comprising two parallel sides separated by a gap, wherein the second double-cantilever structure permits compliance of the primary fiber in a second direction perpendicular to the two parallel sides of the second double-cantilever structure, wherein the first and second directions are different.

8. The fabricated microstructure of claim 7, wherein the second double-cantilever structure is stacked on top of the first double-cantilever structure.

9. The fabricated microstructure of claim 8, wherein the two parallel sides of the first double-cantilever structure are oriented perpendicular to the two parallel sides of the second double-cantilever structure, and wherein the first direction is perpendicular to the second direction.

10. The fabricated microstructure of claim 1, further comprising:

a plurality of primary fibers arranged in an array, wherein the plurality of base fibers are arranged as an array, and wherein each primary fiber includes an array of base fibers.

11. The fabricated microstructure of claim 10, wherein the array of primary fibers and array of base fibers have area fractions of about 10 to 20 percent of areas with a base fiber or primary fiber to area without a base fiber or primary fiber.

12. A method of fabricating a microstructure having a plurality of micro- or nano-fibers attached to a compliant substrate, comprising:

stacking a first porous mold on a second porous mold, wherein the first and second porous molds have different pore sizes, and wherein the first and second porous molds are shaped to form a plurality of primary fibers, each primary fiber having a width less than about 5 microns, and each primary fiber having a plurality of base fibers, wherein each base fiber has a width less than the width of the primary fiber;

filling the stacked first and second porous molds with polymer;

curing the polymer;

after curing the polymer, etching away the first and second porous molds; and

cutting the polymer using a cutting beam.

13. A fabricated microstructure, comprising:

a substrate; and

a micro- or nano-fiber having a base attached to the substrate, wherein the fiber has a width less than about 5 microns, wherein the base includes a first double-cantilever structure, and wherein the first double-cantilever structure comprises two parallel sides separated by a gap, wherein the first double-cantilever structure permits compliance of the fiber at the base in a first direction perpendicular to the two parallel sides of the first double-cantilever structure.

14. The fabricated microstructure of claim 13, wherein the base further includes:

a second double-cantilever structure comprising two parallel sides separated by a gap, wherein the second double-cantilever structure permits compliance of the fiber at the base in a second direction perpendicular to the two parallel sides of the second double-cantilever structure, wherein the first and second directions are different.

15. The fabricated microstructure of claim 14, wherein the second double-cantilever structure is stacked on top of the first double-cantilever structure.

16. The fabricated microstructure of claim 15, wherein the two parallel sides of the first double-cantilever structure are oriented perpendicular to the two parallel sides of the second double-cantilever structure, and wherein the first direction is perpendicular to the second direction.

17. The fabricated microstructure of claim 13, wherein the fiber is formed from a polymer with an elastic modulus greater than 500 megapascals.

18. The fabricated microstructure of claim 17, wherein the fiber is formed from epoxy.

19. The fabricated microstructure of claim 13, wherein the substrate is formed from a compliant material.

20. The fabricated microstructure of claim 19, wherein the substrate is formed from a polymer with an elastic modulus less than 10 megapascals.

21. The fabricated microstructure of claim 20, wherein the substrate is formed from silicone rubber.

22. The fabricated microstructure of claim 13, wherein the substrate is formed from a cloth-like material.

23. A fabricated microstructure, comprising:

a substrate; and

a micro- or nano-fiber having a base attached to the substrate, wherein the fiber has a width less than about 5 microns, wherein the base includes a spring structure, and wherein spring structure permits rotational compliance of the fiber at the base.

24. The fabricated microstructure of claim 23, wherein the spring structure is a coil spring structure.

25. The fabricated microstructure of claim 23, wherein the fiber is formed from a polymer with an elastic modulus greater than 500 megapascals, and wherein the substrate is formed from a polymer with an elastic modulus less than 10 megapascals.

26. The fabricated microstructure of claim 25, wherein the fiber is formed from epoxy, and wherein the substrate is formed from silicone rubber.

27. A fabricated microstructure, comprising:

a substrate; and

a micro- or nano-fiber having a base attached to the substrate, wherein the fiber has a width less than about 5 microns, wherein the base includes a flexure support structure, and wherein the flexure support structure permits rotational compliance of the fiber at the base.

28. The fabricated microstructure of claim 27, wherein the flexure support structure is narrower in width than the other portions of the fiber.

29. The fabricated microstructure of claim 27, wherein the fiber is formed from epoxy, and wherein the substrate is formed from silicone rubber.

30. A method of fabricating a microstructure having a plurality of micro- or nano-fibers attached to a compliant substrate, comprising:

inserting a template having an array of holes into the compliant substrate;

applying material for the fibers on top of the template;

planarizing the top of the template after the material for the fibers has been applied; and

removing the template to release the fibers.

31. The method of claim 30, wherein the template is a nanopore array.

32. The method of claim 31, further comprising:

applying a layer of silicone adhesive on to a polyester sheet, wherein the template is inserted into the layer of silicone adhesive before the layer of silicone adhesive has fully cured.

33. The method of claim 30, wherein the material applied on top of the template is epoxy.

34. The method of claim 33, further comprising:

placing the complaint substrate with the inserted template and epoxy applied under vacuum; and

curing the epoxy.

35. The method of claim 30, wherein planarizing the top of the template comprises:

sanding the top of the template with silicon carbide sand paper.

36. The method of claim 30, wherein removing the template comprises:

etching away the template.

37. A fabricated microstructure, comprising:

a substrate; and

a micro- or nano-fiber having a base attached to the substrate, wherein the fiber has a width less than about 5 microns, and wherein the substrate is formed from a compliant material.

38. The fabricated microstructure of claim 37, wherein the fiber is formed from a polymer with an elastic modulus greater than 500 megapascals, and wherein the substrate is formed from a polymer with an elastic modulus less than 10 megapascals.