FLEXIBLE ELECTRICALLY CONDUCTIVE NANOTUBE SENSOR FOR ELASTOMERIC DEVICES

• US 20130213140A1
• Filed: 08/30/2012
• Published: 08/22/2013
• Est. Priority Date: 02/16/2012
• Status: Active Grant

• Current Assignee: 7-Sigma Inc.
• Original Assignee: 7-Sigma Inc.
• Inventors: Eichhorn, Wade R., Duda, Richard, Wyrobek, Kristian G., Sezen, Ahmet Serdar
• Granted Patent: US 8,746,075 B2
• Time in Patent Office: Days
• US Class Current: 73/774
• CPC Class Codes: A61B 2562/0261 Strain gauges
• CPC Class Codes: A61B 2562/0285 Nanoscale sensors
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/6853 with a balloon
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01L 1/2206 Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
• CPC Class Codes: G01L 9/0035 using variations in ohmic resistance

Abstract

A flexible substrate has a major surface and a sensor attached to and aligned with the major surface of the substrate. The sensor may have an elastic body containing conductive nanotubes homogeneously distributed therein to form a conductive path and at least two electrodes in electrical connection with the conductive path. Balloons and flexible elements used in medical procedures are particularly useful.

Claims

1. A flexible substrate having a major surface and a sensor attached to and aligned with the major surface of the substrate, wherein:

the sensor comprises an elastic body containing conductive nanotubes homogeneously distributed therein to form a conductive path and at least two electrodes in electrical connection with the conductive path.

2. The substrate of claim 1 wherein the at least two electrodes of the sensor are in communication with both a power source and a processor.

3. The substrate of claim 2 wherein the sensor adhered to the major surface or embedded in the major surface.

5. The substrate of claim 1 wherein the major surface comprises an elastomeric composition having a first modulus of elasticity and the elastic body of the sensor has a second modulus of elasticity and wherein the first modulus of elasticity is within 40% of the second modulus of elasticity.

6. The substrate of claim 2 wherein the major surface comprises an elastomeric composition having a first modulus of elasticity and the elastic body of the sensor has a second modulus of elasticity and wherein the first modulus of elasticity is within 40% of the second modulus of elasticity.

7. The substrate of claim 1 wherein the major surface is on an inflatable balloon having a conduit for transporting fluid into a cavity of the balloon to alter stress on the major surface of the inflatable balloon.

8. The substrate of claim 7 wherein presence of a nominally maximum fluid volume within the cavity maintains at least a 0.01 mm/m extension of a dimension in the elastic body of the sensor.

9. The substrate of claim 7 wherein the major surface comprises an elastomeric composition having a first modulus of elasticity and the elastic body of the sensor has a second modulus of elasticity and wherein the first modulus of elasticity is within 40% of the second modulus of elasticity.

10. The substrate of claim 8 wherein the major surface comprises an elastomeric composition having a first modulus of elasticity and the elastic body of the sensor has a second modulus of elasticity and wherein the first modulus of elasticity is within 40% of the second modulus of elasticity.

11. The substrate of claim 5 wherein the two electrodes of the sensor are in communication with both a power source and a processor.

12. The substrate of claim 6 wherein the two electrodes of the sensor are in communication with both a power source and a processor.

13. The substrate of claim 7 wherein the two electrodes of the sensor are in communication with both a power source and a processor.

14. The sensor of claim 1 wherein the sensor comprises an elastic body of a silicone rubber containing a loading of between 0.5% and 3%, by total weight of conductive nanotubes.

15. The substrate of claim 14 wherein at least two electrodes of the sensor are in communication with both a power source and a processor.

16. The substrate of claim 15 wherein the major surface is on an inflatable balloon having a conduit for transporting fluid into a cavity of the balloon to alter stress on the major surface of the inflatable balloon.

17. The substrate of claim 16 wherein the major surface comprises an elastomeric composition having a first modulus of elasticity and the elastic body of the sensor has a second modulus of elasticity and wherein the first modulus of elasticity is within 40% of the second modulus of elasticity.

18. The substrate of claim 17 wherein the major surface is on an inflatable balloon having a conduit for transporting fluid into a cavity of the balloon to alter stress on the major surface of the inflatable balloon.

19. The substrate of claim 16 wherein the major surface is on an expandable balloon element in a medical device that applies localized pressure in a patient.

20. The substrate of claim 18 wherein the major surface is on an expandable balloon element in a medical device that applies localized pressure in a patient.

21. The substrate of claim 16 wherein the sensor comprises an electrically conductive silicone rubber composite comprised of a liquid silicone rubber with a multi-wall carbon nanotube loading of between 1%-3% by weight and a hardness between 10 and 60 Asker C hardness.

4. The flexible substrate wherein the major surface is non-conductive.

22. A method of detecting stress, pressure or dimensional changes within an environment comprising positioning within the environment a substrate having a major surface and a sensor attached to and aligned with the major surface of the substrate, the sensor comprises an elastic body containing conductive nanotubes homogeneously distributed therein to form a conductive path and at least two electrodes in electrical connection with the conductive path;

applying a current across the sensor through one of the at least two electrodes;

determining changes in the current or voltage; and

providing signals indicating changes in the current to a processor; and

the processor executing code to correlate determined changes in the current to stress, pressure or dimensional changes in the sensor.