Actively switchable nano-structured adhesive

• US 7,914,912 B2
• Filed: 11/10/2005
• Issued: 03/29/2011
• Est. Priority Date: 11/10/2004
• 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: Groff, Richard, Fearing, Ronald S., Majidi, Carmel, Bachrach, Abraham
• Primary Examiner(s): Ruthkosky; Mark
• Assistant Examiner(s): Reddy; Sathavaram I
• Application Number:
  US11/271,103
• Publication Number:
  US 20080014465A1
• Time in Patent Office: 1,965 Days
• Field of Search: None
• US Class Current: 428/692.1
• CPC Class Codes: B81B 3/0032 Structures for transforming energy not provided for in groups B81B3/0021 - B81B3/0029
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/32 Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

Described herein is a microstructure having a substrate and a plurality of nano-fibers attached to the substrate. Each nano-fiber moves between the first and second states without an external mechanical load being applied to the nano-fibers. Each nano-fiber is configured to move between a first state and a second state in response to applied electricity, magnetism, chemical solution, heat, or light. Each nano-fiber is straight in the first state and curved in the second state, and when the nano-fibers are in the second state and in contact with a contact surface, the nano-fibers adhere to the contact surface.

Claims

1. A fabricated microstructure, comprising:

a substrate;

a set of electrodes or a wire disposed on the substrate; and

a nano-fiber attached to the substrate,

wherein the nano-fiber is differentially coated with an electroactive polymer, magnetostrictive material, paramagnetic, or ferromagnetic material to leave a portion of the nano-fiber coated with the electroactive polymer, magnetostrictive material, paramagnetic, or ferromagnetic material and another portion of the nano-fiber uncoated,

wherein the nano-fiber is electrically isolated from said set of electrodes or wire,

the nano-fiber configured to move between a first state and a second state in response to an electric field applied by the set of electrodes or magnetic field applied by the wire, wherein the nano-fiber is straight in the first state and curved in the second state, wherein, when the nano-fiber is in the first state and in contact with a contact surface, the nano-fiber does not adhere to the contact surface, and wherein, when the nano-fiber is in the second state and in contact with the contact surface, the nano-fiber adheres to the contact surface.

2. The fabricated microstructure of claim 1,

wherein in response to an applied voltage, the electrodes generate the electric field that activates the electroactive polymer on the nano-fiber to bend the nano-fiber.

3. The fabricated microstructure of claim 1, wherein in response to the applied magnetic field generated by the wire, the magnetostrictive material on the nano-fiber bends the nano-fiber.

4. The fabricated microstructure of claim 1,

wherein in response to an applied current, the wire generates the magnetic field that activates the paramagnetic or ferromagnetic material to bend the nano-fiber.

5. The fabricated microstructure of claim 1, wherein the nano-fiber moves between the first and second states without an external mechanical load being applied to the nano-fiber.

6. The fabricated microstructure of claim 1, wherein the entire length of the nano-fiber is curved.

7. A fabricated microstructure, comprising:

a substrate;

a set of electrodes disposed on the substrate; and

a plurality of nano-fibers attached to the substrate,

wherein the nano-fibers are differentially coated with an electroactive polymer material to leave a portion of each nano-fiber coated with the electroactive polymer and another portion of the nano-fiber uncoated,

wherein the nano-fibers are electrically isolated from said set of electrodes,

the nano-fibers configured to move between a first state and a second state in response to an electric field applied by the set of electrodes, wherein each nano-fiber is straight in the first state and curved in the second state, wherein, when the nano-fibers are in the first state and in contact with a contact surface, the nano-fibers do not adhere to the contact surface, and wherein, when the nano-fibers are in the second state and in contact with the contact surface, the nano-fibers adhere to the contact surface.

8. The fabricated microstructure of claim 7, wherein in response to an applied voltage, the electrodes generate the electric field that activates the electroactive polymer on the nano-fibers to bend the nano-fibers.

9. The fabricated microstructure of claim 7, wherein the nano-fibers move between the first and second states without an external mechanical load being applied to the nano-fibers.

10. The fabricated microstructure of claim 7, wherein the entire length of each nano-fiber is curved.

11. A fabricated microstructure, comprising:

a substrate;

a wire disposed on the substrate; and

a plurality of nano-fibers attached to the substrate,

wherein the nano-fibers are differentially coated with a magnetostrictive material to leave a portion of each nano-fiber coated with the magnetostrictive material and another portion of the nano-fiber uncoated,

wherein the nano-fibers are electrically isolated from said wire,

the nano-fibers configured to move between a first state and a second state in response to a magnetic field applied by the wire, wherein each nano-fiber is straight in the first state and curved in the second state, wherein, when the nano-fibers are in the first state and in contact with a contact surface, the nano-fibers do not adhere to the contact surface, and wherein, when the nano-fibers are in the second state and in contact with a contact surface, the nano-fibers adhere to the contact surface.

12. The fabricated microstructure of claim 11, wherein in response to the magnetic field the magnetostrictive material bends the nano-fibers.

13. The fabricated microstructure of claim 11, wherein the nano-fibers move between the first and second states without an external mechanical load being applied to the nano-fibers.

14. The fabricated microstructure of claim 11, wherein the entire length of each nano-fiber is curved.

15. A fabricated microstructure, comprising:

a substrate;

a wire disposed on the substrate; and

a plurality of nano-fibers attached to the substrate,

wherein the nano-fibers are differentially coated with a paramagnetic or ferromagnetic material to leave a portion of each nano-fiber coated with the paramagnetic or ferromagnetic material and another portion of the nano-fiber uncoated,

wherein the nano-fibers are electrically isolated from said wire,

the nano-fibers configured to move between a first state and a second state in response to a magnetic field applied by the wire, wherein each nano-fiber is straight in the first state and curved in the second state, wherein, when the nano-fibers are in the first state and in contact with a contact surface, the nano-fibers do not adhere to the contact surface, and wherein, when the nano-fibers are in the second state and in contact with a contact surface, the nano-fibers adhere to the contact surface.

16. The fabricated microstructure of claim 15, wherein in response to the magnetic field the paramagnetic or ferromagnetic material bends the nano-fibers.

17. The fabricated microstructure of claim 15, wherein the nano-fibers move between the first and second states without an external mechanical load being applied to the nano-fibers.