Electroactive polymers

• US 6,812,624 B1
• Filed: 07/20/2000
• Issued: 11/02/2004
• Est. Priority Date: 07/20/1999
• Status: Expired due to Term

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Pei, Qibing, Pelrine, Ronald E., Kornbluh, Roy D.
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/619,847
• Time in Patent Office: 1,566 Days
• Field of Search: 310/309, 310/800
• US Class Current: 310/309
• CPC Class Codes: F02G 1/043 the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines
• 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: F05C 2225/08 Thermoplastics
• CPC Class Codes: F25B 9/14 characterised by the cycle used, e.g. Stirling cycle
• CPC Class Codes: H01G 5/16 using variation of distance between electrodes
• CPC Class Codes: H02N 2/023 Inchworm motors
• 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: H10N 30/098 Forming organic materials
• CPC Class Codes: H10N 30/2042 Cantilevers, i.e. having one fixed end
• CPC Class Codes: H10N 30/206 using only longitudinal or thickness displacement, e.g. d33 or d31 type devices
• CPC Class Codes: H10N 30/30 with mechanical input and electrical output, e.g. functioning as generators or sensors
• CPC Class Codes: H10N 30/308 Membrane type
• CPC Class Codes: H10N 30/857 Macromolecular compositions
• CPC Class Codes: H10N 30/87 Electrodes or interconnections, e.g. leads or terminals
• 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: Y10T 29/49826 : Assembling or joining

Abstract

The present invention relates to transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention also relates to devices including an electroactive polymer to convert between electrical and mechanical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

Claims

1. A transducer for converting between mechanical and electrical energy, the transducer comprising:

at least two electrodes; and

a polymer arranged in a manner which causes a portion of the polymer to deflect in response to a change in electric field and/or arranged in a manner which causes a change in electric field in response to deflection of the polymer, wherein the polymer includes an additive to improve the operating performance of the transducer and wherein the polymer has an elastic modulus at most about 100 MPa without electrical energy applied thereto.

2. The transducer of claim 1 wherein the additive improves at least one of polymer dielectric breakdown strength, maximum linear strain, dielectric constant, elastic modulus, response time, and actuation voltage.

3. The transducer of claim 1 wherein the additive comprises at least one of a plasticizer, an antioxidant, and a high dielectric constant particulate.

4. The transducer of claim 3 wherein the plasticizer comprises a material selected from a group consisting of high molecular-weight hydrocarbon oil, high molecular-weight hydrocarbon grease Pentalyne H, Piccovar®

AP Hydrocarbon Resin, Admex 760, Plastolein 9720, silicone oil, silicone grease, Floral 105, silicone elastomers, nonionic surfactants, and combinations thereof.

5. The transducer of claim 3 wherein the antioxidant is a nonvolatile solid antioxidant.

6. The transducer of claim 3 wherein the plasticizer reduces the elastic modulus of the polymer and/or increases the dielectric breakdown strength of the polymer.

7. The transducer of claim 1 wherein the additive improves one of the ability of the polymer to convert between mechanical and electrical energy and an adhesion of the polymer.

8. The transducer of claim 1 wherein the polymer is elastically pre-strained.

9. The transducer of claim 1 wherein the transducer is included in an actuator, a generator, and a sensor.

10. The transducer of claim 1 wherein the transducer is included in one of a robot, a motor, a pump, or a toy.

11. A transducer for converting between mechanical and electrical energy, the transducer comprising:

at least two electrodes; and

a polymer arranged in a manner which causes a portion of the polymer to deflect in response to a change in electric field and/or arranged in a manner which causes a change in electric field in response to deflection of the polymer, wherein the polymer includes an additive to improve the operating performance of the transducer and wherein the polymer is elastically pre-strained by a factor in the range of about 1.5 times to 50 times an original area of the polymer.

12. The transducer of claim 11 wherein the additive improves at least one of polymer dielectric breakdown strength, maximum linear strain, dielectric constant, elastic modulus, response time, and actuation voltage.

13. The transducer of claim 11 wherein the additive comprises at least one of a plasticizer, an antioxidant, and a high dielectric constant particulate.

14. The transducer of claim 13 wherein the plasticizer comprises a material selected from a group consisting of high molecular-weight hydrocarbon oil, high molecular-weight hydrocarbon grease, Pentalyne H, Piccovar®

AP Hydrocarbon Resins, Adriex 760, Plastolein 9720, silicone oil grease, Floral 105, silicone elastomers, nonionic surfactants, and combinations thereof.

15. The transducer of claim 13 wherein antioxidant is a nonvolatile solid antioxidant.

16. The transducer of claim 13 wherein the plasticizer reduces the elastic modulus of the polymer and/or increases the dielectric breakdown strength of the polymer.

17. The transducer of claim 11 wherein the additive improves one of an ability of the polymer to convert between mechanical and electrical energy and an adhesion of the polymer.

18. The transducer of claim 11 wherein the transducer is included in one of an actuator, a generator, or a sensor.

19. The transducer of claim 11 wherein the transducer is included in one of a robot, a motor, a pump, or a toy.