FLEXIBLE IMPACT SENSORS AND METHODS OF MAKING SAME

• US 20100126273A1
• Filed: 11/24/2009
• Published: 05/27/2010
• Est. Priority Date: 11/25/2008
• Status: Abandoned Application

• Current Assignee: New Jersey Institute of Technology
• Original Assignee: New Jersey Institute of Technology
• Inventors: Lim, Hee Chuan, Hor, Yew Fong
• Application Number:
  US12/624,898
• Publication Number:
  US 20100126273A1
• Time in Patent Office: Days
• US Class Current: 73/514.160
• CPC Class Codes: G01P 15/04 for indicating maximum value
• CPC Class Codes: G01P 15/06 using members subjected to a permanent deformation
• CPC Class Codes: G01P 15/12 by alteration of electrical resistance G01P15/0897, G01P15/105 take precedence
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges

Abstract

Flexible impact sensors are provided which are constructed of flexible polyimide substrate, electrodes and a pressure-sensitive electrically conductive polymer composite layer having conductive nanoparticles. Dual-purpose impact and temperature sensors are also described. Methods of making flexible impact sensors are disclosed.

Claims

1. An impact sensor comprising at least one conductive polymer layer, a flexible substrate, and at least one electrode pair disposed between the at least one conductive polymer layer and the flexible substrate.

2. The impact sensor according to claim 1 wherein the flexible substrate comprises a polyimide membrane.

3. The impact sensor according to claim 1 wherein the conductive polymer layer is pressure sensitive and comprises a cross-linked synthetic polymer matrix and conductive nanoparticles.

4. The impact sensor according to claim 3 wherein the conductive nanoparticles are selected from the group consisting of silver, gold, copper, and an aqueous solution of Indium Tin Oxide (ITO) and a conductive polymer poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:

PSS).

5. The impact sensor according to claim 1 comprising a conductive electrode pair selected from the group consisting of aluminum, silver, gold, platinum, and copper electrodes.

6. The impact sensor according to claim 1 wherein the conductive polymer layer is encapsulated with SiNx.

7. The impact sensor according to claim 1 wherein the substrate has a thickness of about 20 microns to about 300 microns, a length of about 0.7 cm to about 2.54 cm , and a width of about 0.7 cm to about 2.54 cm.

8. The impact sensor according to claim 1 wherein each electrode has a length of about 0.7 cm to about 2.54 cm and a width of about 0.2 cm to about 0.5 cm.

9. The impact sensor according to claim 1 wherein the polymer layer has a thickness of about 0.5 mm to about 1.0 mm, a length of about 5.0 mm to about 1.5 cm, and a width of about 5.0 mm to about 1.0 cm.

10. The impact sensor according to claim 1 comprising a thickness of about 0.59 mm.

11. A method of making a flexible piezoresistive-based impact sensor comprising providing a flexible polyimide substrate, disposing an electrode pair on the substrate, and disposing on the electrodes a pressure-sensitive electrically conductive polymer composite layer comprising conductive nanoparticles.

12. The method according to claim 11 comprising disposing the electrode pair on the substrate by sputtering a highly conductive material thereon.

13. The method according to claim 11 wherein the conductive nanoparticles are selected from the group consisting of silver, gold, copper, and an aqueous solution of Indium Tin Oxide (ITO) and a conductive polymer poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:

PSS).

14. The method according to claim 11 wherein the electrode pair is selected from the group consisting of aluminum, silver, gold, platinum, and copper electrodes.

15. The method according to claim 11 comprising cleaning the substrate and modifying the substrate for better adhesion of deposited layers.

16. A combined temperature monitor and impact sensor comprising at least one conductive polymer layer, a flexible substrate, and at least one electrode pair disposed between the at least one conductive polymer layer and the flexible substrate.

17. The device according to claim 16 wherein the flexible substrate comprises a polyimide membrane.

18. The device according to claim 16 wherein the conductive polymer layer comprises a cross-linked polymer matrix and conductive nanoparticles.