Electroactive polymer electrodes

• US 6,583,533 B2
• Filed: 11/15/2001
• Issued: 06/24/2003
• Est. Priority Date: 02/07/1997
• Status: Expired due to Term

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Pelrine, Ronald E., Kornbluh, Roy D., Pei, Qibing, Joseph, Jose P.
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/993,871
• Publication Number:
  US 20020050769A1
• Time in Patent Office: 586 Days
• Field of Search: 310/363, 310/800, 310/309
• US Class Current: 310/309
• CPC Class Codes: F02G 2243/52 acoustic
• CPC Class Codes: F04B 35/00 Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
• CPC Class Codes: F04B 35/045 using solenoids
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F04B 43/14 having plate-like flexible members
• CPC Class Codes: F05C 2225/08 Thermoplastics
• CPC Class Codes: H04R 17/005 using a piezoelectric polymer
• CPC Class Codes: H04R 17/08 signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously
• CPC Class Codes: H04R 19/02 Loudspeakers H04R19/01 takes precedence
• CPC Class Codes: H04R 23/00 Transducers other than those covered by groups H04R9/00 - H04R21/00 diaphragms for transducers of the distributed-mode type H04R7/045
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers
• CPC Class Codes: H10N 30/206 using only longitudinal or thickness displacement, e.g. d33 or d31 type devices
• CPC Class Codes: H10N 30/877 Conductive materials
• CPC Class Codes: H10N 30/878 the principal material being non-metallic, e.g. oxide or carbon based
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/753 with polymeric or organic binder
• CPC Class Codes: Y10S 977/788 Of specified organic or carbon-based composition
• CPC Class Codes: Y10S 977/809 Organic film on silicon
• CPC Class Codes: Y10S 977/842 : for carbon nanotubes or fullerenes
• CPC Class Codes: Y10S 977/899 : Electrolytic

Abstract

The present invention relates to electroactive polymers that are pre-strained to improve conversion from electrical to mechanical energy. When a voltage is applied to electrodes contacting a pre-strained polymer, the polymer deflects. This deflection may be used to do mechanical work. The pre-strain improves the mechanical response of an electroactive polymer. The present invention also relates to actuators including an electroactive polymer and mechanical coupling to convert deflection of the polymer into mechanical work. The present invention further relates to compliant electrodes that conform to the shape of a polymer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

Claims

1. An electrode for use with an electroactive polymer, the electrode comprising:

a compliant portion in contact with a portion of the electroactive polymer, wherein the compliant electrode portion deflects with the polymer portion and is capable of deflection with a maximum linear strain of at least about 50 percent.

2. The electrode of claim 1 wherein the electrode portion is compliant in one direction greater than in a second direction.

3. The electrode of claim 1 wherein the electrode portion comprises a textured electrode having a varying depth normal to the surface of the polymer that the compliant portion is in contact with.

4. The electrode of claim 1 wherein the polymer portion is substantially translucent or substantially transparent and the compliant electrode portion comprises an opacity which varies with deflection of the polymer portion.

5. The electrode of claim 1 wherein the electrode portion comprises a high aspect ratio carbon material.

6. The electrode of claim 1 wherein the electrode portion comprises a conductive polymer.

7. The electrode of claim 5 wherein the high aspect ratio carbon material comprises one of a carbon fibril or carbon nanotube material.

8. The electrode of claim 7 wherein the compliant portion has a thickness less than about 4 micrometers.

9. The electrode of claim 5 further comprising a polymer binder to increase adhesion between the high aspect ratio carbon material and the polymer portion.

10. The electrode of claim 1 wherein the compliant portion is capable of deflection with a maximum linear strain of at least about 100 percent.

11. The electrode of claim 1 wherein the compliant portion is in contact with a portion of the electroactive polymer and defines an active area according to the compliant portion geometry.

12. An electrode for use with an electroactive polymer, the electrode comprising:

a compliant portion in contact with a portion of the electroactive polymer, wherein the compliant portion deflects with the polymer portion and comprises an opacity which varies with deflection of the polymer portion.

13. The electrode of claim 12 wherein the electrode is used in an optical switch.

14. The electrode of claim 12 wherein the compliant portion comprises an opacity which varies with planar deflection of the polymer portion.

15. The electrode of claim 14 wherein the compliant portion comprises carbon fibrils.

16. The electrode of claim 12 wherein the electroactive polymer is substantially transparent.

17. The electrode of claim 12 wherein the compliant portion comprises an array of opaque elements that vary the opacity of the compliant portion with deflection of the polymer portion.

18. The electrode of claim 17 wherein the array of elements is disposed on the polymer portion.

19. An electrode for use with an electroactive polymer, the electrode comprising:

means for communicating electrical energy with a portion of the electroactive polymer, wherein the means for communicating electrical energy deflects with the polymer portion and comprises means for varying opacity with deflection of the polymer portion.

20. The electrode of claim 19 wherein the electroactive polymer is substantially translucent or substantially transparent.