Adhesive microstructure and method of forming same

• US 20040005454A1
• Filed: 01/06/2003
• Published: 01/08/2004
• Est. Priority Date: 12/20/1999
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University), Regents of the University of California (University of California)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University), Regents of the University of California (University of California)
• Inventors: Fearing, Ronald S., Autumn, Kellar, Kenny, Thomas W., Full, Robert J.
• Granted Patent: US 7,011,723 B2
• Time in Patent Office: Days
• US Class Current: 428/343
• CPC Class Codes: C09J 2301/31 the adhesive effect being based on a Gecko structure
• CPC Class Codes: C09J 5/00 Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
• CPC Class Codes: C09J 7/00 Adhesives in the form of films or foils
• CPC Class Codes: G01N 19/04 Measuring adhesive force between materials, e.g. of sealing tape, of coating
• CPC Class Codes: G01N 2203/0025 Shearing
• CPC Class Codes: G01N 2203/0286 Miniature specimen; Testing on microregions of a specimen
• CPC Class Codes: G01N 2203/0623 using piezoelectric gauges
• CPC Class Codes: G01N 3/24 by applying steady shearing forces G01N3/26, G01N3/28 take precedence
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/2973 Particular cross section
• CPC Class Codes: Y10T 428/2976 Longitudinally varying
• CPC Class Codes: Y10T 428/2978 Surface characteristic
• CPC Class Codes: Y10T 428/298 Physical dimension

Abstract

A method of forming an adhesive force includes removing a seta from a living specimen, attaching the seta to a substrate, and applying the seta to a surface so as to establish an adhesive force between the substrate and the surface. The seta is applied to the surface with a force perpendicular to the surface. The seta is then pulled with a force parallel to the surface so as to preload the adhesive force of the seta.

Claims

1. A method of forming an adhesive force, said method comprising the steps of:

removing a seta from a living specimen;

attaching said seta to a substrate; and

applying said seta to a surface so as to establish an adhesive force between said substrate and said surface.

2. The method of claim 1 wherein said removing step includes the step of removing a seta from a gecko.

3. The method of claim 1 wherein said removing step includes the step of removing a seta from a living specimen selected from the group consisting of species of Anolis, skink, beetles, and kissing-bugs.

4. The method of claim 1 wherein said applying step includes the steps of:

applying said seta to said surface with a force perpendicular to said surface; and

pulling said seta with a force parallel to said surface so as to engage said adhesive force.

5. The method of claim 4 wherein said adhesive force is greater than the cumulative force of said applying and pulling steps.

6. A method of establishing a adhesive microstructure, said method comprising the steps of:

applying a seta to a surface with a force perpendicular to said surface;

pulling said seta with a force parallel to said surface so as to preload an adhesive force of said seta.

7. The method of claim 6 wherein said adhesive force is greater than the cumulative force of said applying and pulling steps.

8. The method of claim 6 further comprising the step or eliminating said adhesive force by creating a force to produce a detachment angle between said seta and said surface.

9. The method of claim 8 wherein said eliminating step includes the step of creating a force to produce a detachment angle of between 25°

and 35°

between said seta and said surface.

10. The method of claim 8 wherein said eliminating step includes the step of creating a force to produce a detachment angle of approximately 30°

between said set and said surface.

11. A method of fabricating an adhesive microstructure, said method comprising the steps of:

fabricating an array of shafts; and

forming spatulae on said array of shafts.

12. The method of claim 11 wherein said fabricating step includes the step of constructing said array of shafts with a sandwich of nitride and oxide.

13. The method of claim 11 wherein said fabricating step includes the step of constructing said array of shafts with a sandwich of polymer layers.

14. The method of claim 13 wherein said constructing step includes the step of constructing said array of shafts with a sandwich of polymer layers, wherein a polymer layer is a spin-cast polymer material selected from the group consisting of photoresist, polyimide, glass, and epoxy-based compounds.

15. The method of claim 13 wherein said constructing step includes the step of constructing said array of shafts with a sandwich of polymer layers, wherein a polymer layer is a spray-deposited polymer material selected from the group consisting of photoresist, polyimide, glass, and epoxy-based compounds.

16. The method of claim 13 wherein said constructing step includes the step of constructing said array of shafts with a sandwich of polymer layers including ultra violet curable epoxies.

17. The method of claim 11 wherein said fabricating step includes the step of etching a substrate to form molding structures defining the length and shape of said array of shafts.

18. The method of claim 17 further comprising the step of coating said substrate with oxide and nitride layers.

19. The method of claim 17 further comprising the step of coating said substrate with polymer layers.

20. The method of claim 19 wherein said coating step includes the step of spin-cast coating with a material selected from the group consisting of photoresist, polyimide, glass, and epoxy-based compounds.

21. The method of claim 11 wherein said fabricating step includes the step of constructing said array of shafts using excitation energy.

22. The method of claim 11 wherein said forming step includes the step of forming spatulae, wherein the terminal end of individual spatula of said spatulae include an extended surface.

23. The method of claim 11 wherein said forming step includes the step of seeding said array of shafts to form spatulae on said array of shafts.

24. The method of claim 11 wherein said forming step includes the step of roughening said array of shafts to form spatulae on said array of shafts.

25. The method of claim 24 wherein said roughening includes the step of etching said array of shafts to form spatulae on said array of shafts.

26. The method of claim 11 wherein said forming step includes the step of constructing spatulae through micro-pipette deposits.

27. The method of claim 11 wherein said forming step includes the step of constructing spatulae through embossing.

28. The method of claim 11 wherein said forming step includes the step of constructing spatulae through a mold.

29. The method of claim 11 wherein said forming step includes the step of constructing spatulae through lithographically induced self-construction.

30. The method of claim 11 wherein said forming step includes the steps of:

constructing spatulae; and

attaching said spatulae to said array of shafts.

31. A fabricated microstructure, comprising:

a shaft with a length of less than 500 microns, said shaft having a diameter of between 0.01 and 0.1 times said length of said shaft; and

an array of spatulae formed at an end of said shaft, said array of spatulae having a width of less than 10 microns, individual spatula of said spatulae including a curved segment of a sphere at a spatula terminal end.

32. The fabricated microstructure of claim 31 wherein said shaft has a length of between approximately 10 and 100 microns.

33. The fabricated microstructure of claim 31 wherein said shaft has a diameter of approximately 0.05 times said length of said shaft.

34. The fabricated microstructure of claim 31 wherein said curved segment of a sphere at a spatula terminal end has a radius of approximately 2 μ

m.