Adhesive microstructure and method of forming same

• US 7,691,307 B2
• Filed: 03/14/2005
• Issued: 04/06/2010
• Est. Priority Date: 05/13/2002
• 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: Fearing, Ronald S., Setti, Metin
• Primary Examiner(s): Johnson; Christina
• Assistant Examiner(s): SLAWSKI, MAGALI P
• Application Number:
  US11/080,037
• Publication Number:
  US 20050181170A1
• Time in Patent Office: 1,849 Days
• Field of Search: 264/219, 264/220, 264/227, 244/42, 244/52
• US Class Current: 264/220
• CPC Class Codes: A44B 18/0003 Fastener constructions A44B18/0023, A44B18/0046 take precedence
• CPC Class Codes: A44B 18/0049 obtained by moulding processes compression moulding or articles of indefinite length characterised by the shape of the surface B29C43/222; screen moulding B29C67/08
• CPC Class Codes: A44B 18/0061 Male or hook elements A44B18/0053 takes precedence
• CPC Class Codes: B08B 1/00 Cleaning by methods involving the use of tools cleaning hollow articles by methods or apparatus specially adapted thereto B08B9/00
• CPC Class Codes: B08B 7/0028 by adhesive surfaces
• CPC Class Codes: B29C 33/42 characterised by the shape of the moulding surface, e.g. ribs or grooves
• CPC Class Codes: B29L 2031/756 Microarticles, nanoarticles
• CPC Class Codes: B81B 2203/0361 Tips, pillars
• CPC Class Codes: B81B 3/0059 Constitution or structural means for controlling the movement not provided for in groups B81B3/0037 - B81B3/0056
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• 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: F16B 2/005 Means to increase the friction-coefficient
• CPC Class Codes: F16B 5/07 by means of multiple interengaging protrusions on the surfaces, e.g. hooks, coils,
• CPC Class Codes: Y10S 977/84 Manufacture, treatment, or detection of nanostructure
• CPC Class Codes: Y10T 24/27 including readily dissociable fastener having numerous, protruding, unitary filaments randomly interlocking with, and simultaneously moving towards, mating structure [e.g., hook-loop type fastener]
• CPC Class Codes: Y10T 24/2742 having filaments of varied shape or size on same mounting surface
• CPC Class Codes: Y10T 428/23943 Flock surface
• CPC Class Codes: Y10T 428/24008 including fastener for attaching to external surface
• CPC Class Codes: Y10T 428/24174 including sheet or component perpendicular to plane of web or sheet
• CPC Class Codes: Y10T 428/24355 : Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• 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 428/2913 : Rod, strand, filament or fiber
• 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 fabricated microstructure comprising at least one protrusion capable of providing an adhesive force at a surface of between about 60 and 2,000 nano-Newtons. A stalk supports the protrusion at an oblique angle relative to a supporting surface. The microstructure can adhere to different surfaces.

Claims

1. A method of fabricating an adhesive microstructure comprising:

covering a structure having shafts supporting a plurality of stalks at an oblique angle with a molding substance, wherein the stalks have diameters of between about 50 nanometers and 2.0 microns and lengths of between about 0.5 microns and 20 microns;

removing said structure to provide a template;

filling the template with a polymer; and

separating the template from the polymer to form the microstructure, wherein at least one stalk of the microstructure is capable of providing an adhesive force at a surface of between about 60 and 2,000 nano-Newtons.

2. The method of claim 1 wherein the stalks have aspect ratios of 1:

20-50.

3. The method of claim 1 wherein the polymer is a liquid polymer or a sputtered polymer.

4. The method of claim 1 wherein the terminal ends of the stalks have shapes selected from the group consisting of a curved segment of a sphere, a flattened segment of a sphere, a sphere, a flattened surface, and an end of a cylinder.

5. The method of claim 1 wherein the molded structure has a flexible supporting surface.

6. The method of claim 1 wherein the at least one stalk of the microstructure has a Young'"'"'s modulus of between about 0.1 and 20 giga-Pascals.

7. The method of claim 1 wherein the at least one stalk of the microstructure is hydrophobic.

9. The method of claim 1 wherein the shafts have diameters of between about 1 and 10 microns and lengths of between about 1 microns and 500 microns.

8. A method of fabricating an adhesive microstructure comprising:

covering a structure having shafts supporting a plurality of stalks at an oblique angle with a molding substance, wherein the shafts have diameters of between about 1 and 10 microns and lengths of between about 1 microns and 500 microns, and wherein the stalks have diameters of between about 50 nanometers and 2.0 microns and lengths of between about 0.5 microns and 20 microns;

removing said structure to provide a template;

filling the template with a polymer; and

separating the template from the polymer to form the microstructure, wherein at least one stalk of the microstructure is capable of providing an adhesive force at a surface of between about 60 and 2,000 nano-Newtons.

10. The method of claim 8 wherein the polymer is a liquid polymer or a sputtered polymer.

11. The method of claim 8 wherein the terminal ends of the stalks have shapes selected from the group consisting of a curved segment of a sphere, a flattened segment of a sphere, a sphere, a flattened surface, and an end of a cylinder.

12. The method of claim 8 wherein the molded structure has a flexible supporting surface.

13. The method of claim 8 wherein the at least one stalk of the microstructure has a Young'"'"'s modulus of between about 0.1 and 20 giga-Pascals.

14. A method of fabricating an adhesive microstructure comprising:

covering a structure having shafts supporting a plurality of stalks at an oblique angle of between about 15 and 75 degrees with a molding substance, wherein the shafts have diameters of between about 1 and 10 microns and lengths of between about 1 microns and 500 microns, and wherein the stalks have diameters of between about 50 nanometers and 2.0 microns and lengths of between about 0.5 microns and 20 microns;

removing said structure to provide a template;

filling the template with a polymer; and

separating the template from the polymer to form the microstructure, wherein at least one stalk of the microstructure is capable of providing an adhesive force at a surface of between about 60 and 2,000 nano-Newtons.

15. The method of claim 14 wherein the oblique angle is between about 30 and 60 degrees.

16. The method of claim 14 wherein the oblique angle is about 30 degrees.

17. The method of claim 14 wherein the polymer is a liquid polymer or a sputtered polymer.

18. The method of claim 14 wherein the terminal ends of the stalks have shapes selected from the group consisting of a curved segment of a sphere, a flattened segment of a sphere, a sphere, a flattened surface, and an end of a cylinder.

19. The method of claim 14 wherein the molded structure has a flexible supporting surface.

20. The method of claim 14 wherein the at least one stalk of the microstructure has a Young'"'"'s modulus of between about 0.1 and 20 giga-Pascals.