Electroactive nanostructured polymers as tunable organic actuators

• US 7,956,520 B2
• Filed: 11/19/2007
• Issued: 06/07/2011
• Est. Priority Date: 11/24/2006
• Status: Expired due to Fees

• Current Assignee: North Carolina State University (University of North Carolina System)
• Original Assignee: North Carolina State University (University of North Carolina System)
• Inventors: Shankar, Ravi, Spontak, Richard J., Ghosh, Tushar K.
• Primary Examiner(s): Dougherty; Thomas M
• Application Number:
  US12/515,761
• Publication Number:
  US 20100141092A1
• Time in Patent Office: 1,296 Days
• Field of Search: 310/800
• US Class Current: 310/12.13
• CPC Class Codes: H10N 30/206 using only longitudinal or thickness displacement, e.g. d33 or d31 type devices
• CPC Class Codes: H10N 30/857 Macromolecular compositions
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF

Abstract

An actuator element formed from an actuator composition is described, along with transducers including the same. The composition comprises: (i) a thermoplastic elastomer copolymer, the copolymer comprising at least one flexible midblock, and at least two glassy or semicrystalline endblocks; and (ii) a liquid modifier that selectively solvates the at least one flexible midblock.

Claims

1. A transducer useful in an electromechanical device, said transducer comprising:

(a) at least one electrode; and

(b) an actuator element operatively associated with said at least one electrode, said actuator element formed from an actuator composition comprising;

(i) at least one thermoplastic elastomer copolymer, said copolymer comprising at least one flexible midblock and at least two glassy or semicrystalline endblocks; and

(ii) at least one organic solvent that selectively solvates said at least one flexible midblock.

2. The transducer of claim 1, wherein said flexible midblock is a polyolefin or polydiene midblock.

3. The transducer of claim 1, wherein said flexible midblock is selected from the group consisting of:

ethylene-co-butylene, ethylene-co-propylene, ethylene-ethylene-co-propylene, isoprene, butadiene, and derivatives thereof.

4. The transducer of claim 1, wherein said endblocks are aromatic or acrylic endblocks.

5. The transducer of claim 1, wherein said endblocks are selected from the group consisting of styrene endblocks, methacrylate endblocks, and derivatives thereof.

6. The transducer of claim 1, wherein said copolymer is selected from the group consisting of:

poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS);

poly[styrene-b-(ethylene-co-propylene)-b-styrene] (SEPS);

poly[styrene-b-(ethylene-ethylene-co-propylene)-b-styrene] (SEEPS);

poly(styrene-b-isoprene-b-styrene) (SIS);

poly(styrene-b-butadiene-b-styrene) (SBS);

and derivatives thereof.

7. The transducer of claim 1, wherein said solvent is an oil having a boiling point greater than 50°

C.

8. The transducer of claim 1, wherein said actuator element is formed by molding, extruding, or casting.

9. The transducer of claim 1, wherein said actuator composition comprises a thermoplastic elastomer gel.

10. The transducer of claim 1, wherein:

said thermoplastic elastomer has a molecular weight greater than 10,000;

said solvent has a molecular weight less than 10,000;

said thermoplastic elastomer is included in said actuator composition in an amount of from 2 to 80 percent by weight; and

said solvent is included in said actuator composition in an amount of from 98 to 2 percent by weight.

11. An electromechanical device comprising a transducer of claim 1.

12. The electromechanical device of claim 11, wherein said device is an actuator, generator, sensor, robot, prosthetic limb, motor, pump, valve, toy, catheter, or stent.

13. A transducer useful in an electromechanical device, said transducer comprising:

(a) at least one electrode; and

(b) an actuator element operatively associated with said at least one electrode, said actuator element formed from an actuator composition comprising;

(i) at least one thermoplastic elastomer copolymer, said copolymer comprising at least one flexible midblock and at least two glassy or semicrystalline endblocks; and

(ii) at least one organic solvent that selectively solvates said at least one flexible midblock;

wherein;

said flexible midblock is a polyolefin or polydiene midblock;

said endblocks are aromatic or acrylic endblocks;

said solvent is an oil having a boiling point greater than 50°

C.;

said actuator composition comprises a thermoplastic elastomer gel;

said thermoplastic elastomer has a molecular weight greater than 10,000;

said solvent has a molecular weight less than 10,000;

said thermoplastic elastomer is included in said actuator composition in an amount of from 2 to 80 percent by weight; and

said solvent is included in said actuator composition in an amount of from 98 to 2 percent by weight.

14. The transducer of claim 13, wherein said flexible midblock is selected from the group consisting of:

ethylene-co-butylene, ethylene-co-propylene, ethylene-ethylene-co-propylene, isoprene, butadiene, and derivatives thereof.

15. The transducer of claim 13, wherein said endblocks are selected from the group consisting of styrene endblocks, methacrylate endblocks, and derivatives thereof.

16. The transducer of claim 13, wherein said copolymer is selected from the group consisting of:

poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS);

poly[styrene-b-(ethylene-co-propylene)-b-styrene] (SEPS);

poly[styrene-b-(ethylene-ethylene-co-propylene)-b-styrene] (SEEPS);

poly(styrene-b-isoprene-b-styrene) (SIS);

poly(styrene-b-butadiene-b-styrene) (SBS);

and derivatives thereof.

17. The transducer of claim 13, wherein said actuator element is formed by molding, extruding, or casting.

18. An electromechanical device comprising a transducer of claim 13.

19. The electromechanical device of claim 18, wherein said device is an actuator, generator, sensor, robot, prosthetic limb, motor, pump, valve, toy, catheter, or stent.

20. An actuator element formed from an actuator composition, said composition comprising:

(i) at least one thermoplastic elastomer copolymer, said copolymer comprising at least one flexible midblock, and at least two glassy or semicrystalline endblocks; and

(ii) at least one organic solvent that selectively solvates said at least one flexible midblock.

21. The actuator element of claim 20, wherein said flexible midblock is a polyolefin or polydiene midblock.

22. The actuator element of claim 20, wherein said flexible midblock is selected from the group consisting of:

ethylene-co-butylene, ethylene-co-propylene, ethylene-ethylene-co-propylene, isoprene, butadiene, and derivatives thereof.

23. The actuator element of claim 20, wherein said endblocks are aromatic or acrylic endblocks.

24. The actuator element of claim 20, wherein said endblocks are selected from the group consisting of styrene endblocks, methacrylate endblocks, and derivatives thereof.

25. The actuator element of claim 20, wherein said copolymer is selected from the group consisting of:

poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS);

poly[styrene-b-(ethylene-co-propylene)-b-styrene] (SEPS);

poly[styrene-b-(ethylene-ethylene-co-propylene)-b-styrene] (SEEPS);

poly(styrene-b-isoprene-b-styrene) (SIS);

poly(styrene-b-butadiene-b-styrene) (SBS);

and derivatives thereof.

26. The actuator element claim 20, wherein said solvent is an oil having a boiling point greater than 50°

C.

27. The actuator element of claim 20, wherein said actuator element is formed by molding, extruding, or casting.

28. The actuator element of claim 20, wherein said actuator composition comprises a thermoplastic elastomer gel.

29. The actuator element of claim 20, wherein:

said thermoplastic elastomer has a molecular weight greater than 10,000;

said solvent has a molecular weight less than 10,000;

said thermoplastic elastomer is included in said actuator composition in an amount of from 2 to 80 percent by weight; and

said solvent is included in said actuator composition in an amount of from 98 to 2 percent by weight.