Stretchable ionics for transparent sensors and actuators

• US 10,302,586 B2
• Filed: 04/10/2014
• Issued: 05/28/2019
• Est. Priority Date: 04/10/2013
• Status: Active Grant

• Current Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Sun, Jeong Yun, Keplinger, Christoph Matthias, Suo, Zhigang, Whitesides, George M.
• Primary Examiner(s): Caputo, Lisa M
• Assistant Examiner(s): Plumb, Nigel H
• Application Number:
  US14/768,850
• Publication Number:
  US 20160025669A1
• Time in Patent Office: 1,874 Days
• CPC Class Codes: G01N 27/02 by investigating impedance
• CPC Class Codes: G01N 27/305 optically transparent or photoresponsive electrodes
• CPC Class Codes: G01N 27/3335 the membrane containing at least one organic component G01N27/3271 takes precedence; aspects concerning the enzyme reagent in enzyme electrodes C12Q1/001
• CPC Class Codes: H01G 9/022 Electrolytes; Absorbents

Abstract

A class of devices enabled by ionic conductors is highly stretchable, fully transparent to light of all colors, biocompatible or biodegradable, and capable of operation at frequencies beyond 10 kilohertz and voltages above 10 kilovolts. These devices enabled by ionic conductors can be used as large strain actuators, full-range loudspeakers, as strain or pressure sensors and as stretchable interconnects. The electromechanical transduction is achieved without electrochemical reaction. When large stretchability and high optical transmittance are required, the ionic conductors have lower sheet resistance than all existing electronic conductors.

Claims

1. An electrode comprising:

an ionic electrode;

at least an external signal and

a dielectric layer comprising an elastomer,

wherein the ionic electrode is capacitively coupled with the external signal by the dielectric layer.

2. The electrode of claim 1, wherein the ionic electrode further comprises an ionic electrolyte;

wherein the ionic electrolyte comprises an elastomer or electroactive polymer and an electrolyte dispersed throughout the elastomer or electroactive polymer to provide a transparent electrolyte.

3. The electrode of claim 2, wherein the electrolyte layer elastomer comprises a hydrogel or a lyogel.

4. The electrode of claim 2, wherein the electrolyte comprises an aqueous salt solution.

5. The electrode of claim 4, wherein aqueous salt solution comprises a deliquescent salt.

6. The electrode of claim 4, wherein the aqueous salt solution has a salt concentration in the range of fully saturated to isotonic in physiological systems.

7. The electrode of claim 6, wherein the physiological systems are cells.

8. The electrode of claim 2, wherein the electrolyte comprises an ionic liquid.

9. The electrode of claim 8, wherein the ionic liquid forms a liquid layer.

10. The electrode of claim 9, wherein the liquid layer is confined within boundaries to prevent flow.

11. The electrode of claim 8, wherein an elastomer is swollen with the ionic liquid to provide an elastomeric ionic electrode.

12. The electrode of claim 2, wherein the electrolyte further comprises a humectant.

13. The electrode of claim 2, wherein electrolyte solution has a minimum resistivity of 0.02 Ohm-meter.

14. The electrode of claim 2, wherein the electrolyte has a transmittance of greater than 95%.

15. The electrode of claim 2, further comprising electrical connectors in electrical contact with the transparent electrolyte for connection to an electronic circuit.

16. The electrode of claim 1, wherein the dielectric layer is transparent.

17. The electrode of claim 16, wherein the dielectric layer is elastomeric.

18. The electrode of claim 16, wherein the dielectric layer is an electroactive polymer.

19. The electrode of claim 16, wherein the dielectric layer is biodegradable or biocompatible.

20. The electrode of claim 18, wherein the electroactive polymer is a piezoelectric polymer.

21. The electrode of claim 1, wherein the electrode is stretchable.

22. The electrode of claim 1, wherein the electrode is biodegradable or biocompatible.

23. The electrode of claim 1, wherein the electrode is encapsulated to reduce loss of electrolyte.

24. The electrode of claim 1, wherein the electrode is configured as a stretchable wire or interconnect for use in circuits.