ROLLED ELECTROACTIVE POLYMERS

• US 20080022517A1
• Filed: 04/03/2007
• Published: 01/31/2008
• Est. Priority Date: 05/22/2001
• Status: Active Grant

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Bonwit, Neville, Pei, Qibing, Rosenthal, Marcus
• Granted Patent: US 7,761,981 B2
• Time in Patent Office: Days
• US Class Current: 29/829
• CPC Class Codes: A61M 2205/0283 Electro-active polymers [EAP]
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: F01L 1/46 Component parts, details, or accessories, not provided for in preceding subgroups
• CPC Class Codes: F01L 2301/00 Using particular materials
• CPC Class Codes: F01L 7/02 with cylindrical, sleeve, or part-annularly shaped valves of disc type F01L7/06; of conical type F01L7/08
• CPC Class Codes: F01L 9/20 by electric means
• 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 43/043 Micropumps
• CPC Class Codes: H02N 11/006 Motors
• CPC Class Codes: H04R 19/00 Electrostatic transducers
• CPC Class Codes: H04R 2307/029 Diaphragms comprising fibres
• CPC Class Codes: H10N 30/05 Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes
• CPC Class Codes: H10N 30/098 Forming organic materials
• CPC Class Codes: H10N 30/2046 adapted for multi-directional bending displacement
• CPC Class Codes: H10N 30/206 using only longitudinal or thickness displacement, e.g. d33 or d31 type devices
• CPC Class Codes: H10N 30/302 Sensors
• CPC Class Codes: H10N 30/506 of cylindrical shape with stacking in radial direction, e.g. coaxial or spiral type rolls
• CPC Class Codes: H10N 30/802 Drive or control circuitry or methods for piezoelectric or electrostrictive devices not otherwise provided for
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF
• CPC Class Codes: Y10T 29/42 : Piezoelectric device making
• CPC Class Codes: Y10T 29/43 : Electric condenser making
• CPC Class Codes: Y10T 29/49117 : Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49124 : On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49128 : Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49139 : by inserting component lead or terminal into base aperture
• CPC Class Codes: Y10T 29/49155 : Manufacturing circuit on or in base

Abstract

The invention describes rolled electroactive polymer devices. The invention also describes employment of these devices in a wide array of applications and methods for their fabrication. A rolled electroactive polymer device converts between electrical and mechanical energy; and includes a rolled electroactive polymer and at least two electrodes to provide the mechanical/electrical energy conversion. Prestrain is typically applied to the polymer. In one embodiment, a rolled electroactive polymer device employs a mechanism, such as a spring, that provides a force to prestrain the polymer. Since prestrain improves mechanical/electrical energy conversion for many electroactive polymers, the mechanism thus improves performance of the rolled electroactive polymer device.

Claims

1. A method for fabricating an electroactive polymer device, the method comprising:

disposing at least two electrodes on an electroactive polymer;

rolling the electroactive polymer about at least one of a support member, a mechanical linkage, an end cap, a base or combinations thereof to produce an electroactive polymer roll; and

securing the electroactive polymer roll to maintain its rolled configuration.

2. The method of claim 1 wherein the electroactive polymer is rolled about the support member coupled to the mechanical linkage.

3. The method of claim 1 wherein the electroactive polymer is rolled about the end cap rotationally coupled to the support member and the support member rigidly coupled to the base.

4. The method of claim 1 wherein the electroactive polymer is secured to at least one of the support member, the mechanical linkage, the end cap, the base or combinations thereof.

5. The method of claim 4 wherein the polymer roll is secured using at least one of adhesive, a fastener, a pin, a cap or combinations thereof.

6. The method of claim 1, wherein one or more portions of the electroactive polymer is secured in tension.

7. The method of claim 1 wherein the mechanical linkage is for allowing a force or moment generated in a first portion of the electroactive polymer to be communicated to a second portion of the electroactive polymer

8. The method of claim 1 wherein the support member is for providing at least one of a force that strains at least a portion of the electroactive polymer roll, a force for controlling bending in the electroactive polymer roll, and combinations thereof.

9. The method of claim 1 further comprising cutting the electroactive polymer roll at one or more locations to limit a propagation of a force or a moment from a first portion of the electroactive polymer roll to a second portion of the electroactive polymer roll.

10. The method of claim 9 wherein the electroactive polymer roll is cut into a plurality of muscle strands.

11. The method of claim 10 wherein the muscle strands are of varying lengths.

12. The method of claim 10 wherein the muscle strands are secured at three or more points.

13. The device of claim 10 further comprising securing end points of a first muscle strand, stretching or compressing the first muscle strand about an attachment point between the end points to alter a strain in a portion of the first muscle strand and securing the attachment point.

14. The method of claim 1 wherein the electroactive polymer is a dielectric elastomer.