Piezoresistive strain sensors comprising electrically conducting networks in polymeric phase change materials

Patent metadata

Field	Value
Publication number	US-10378876-B2
Application number	US-201615171990-A
Country	US
Kind code	B2
Filing date	Jun 2, 2016
Priority date	Jun 19, 2015
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

Piezoresistive composite materials comprising electrically conductive particles in a polymeric phase change material are provided. Also provided are strain sensors incorporating the composites and methods for detecting mechanical strain using the composites.

First claim

What is claimed is:

1. A strain sensor comprising:
a composite comprising crosslinked polyether polyol and electrically conductive particles dispersed in the crosslinked polyether polyol, wherein the crosslinked polyether polyol is crosslinked by branched, urethane group-containing linkages or by branched, ether group-containing linkages; and
a probe configured to measure a strain-induced change in the electrical conductance of the composite.

2. The sensor of claim 1 , wherein the electrically conductive particles are carbon particles.

3. The sensor of claim 2 , wherein the carbon particles comprise carbon nanotubes.

4. The sensor of claim 2 , wherein the carbon particles comprise graphene.

5. The sensor of claim 1 , wherein the electrically conductive particles are metal particles.

6. The sensor of claim 1 , wherein the composite is characterized in that its electrical conductivity decreases by a factor of at least 1000 under a tensile strain of 500%.

7. The sensor of claim 1 , wherein the crosslinked polyether polyol is crosslinked by the branched, urethane group-containing linkages.

8. A sensor comprising:
a composite comprising crosslinked polytetrahydrofuran and electrically conductive particles dispersed in the crosslinked polytetrahydrofuran; and
a probe configured to measure a strain-induced change in the electrical conductance of the composite.

9. The sensor of claim 8 , wherein the polytetrahydrofuran is crosslinked by branched, urethane group-containing linkages.

10. The sensor of claim 9 , wherein the urethane groups are part of an aryl group.

11. The sensor of claim 10 , wherein the crosslinked polytetrahydrofuran has the structure:

where n and m represent the number of repeat units in the polytetrahydrofuran chain and the crosslinked polytetrahydrofuran, respectively.

12. A method of sensing a strain, the method comprising:
exposing a composite to a strain, the composite comprising crosslinked polyether polyol and electrically conductive particles dispersed in the crosslinked polyether polyol, wherein the crosslinked polyether polyol is crosslinked by branched, urethane group-containing linkages or by branched, ether group-containing linkages; and
measuring a strain-induced decrease in the electrical conductance of the composite.

13. The method of claim 12 , wherein the polyether polyol is polytetrahydrofuran.

14. The method of claim 13 , wherein the polytetrahydrofuran is crosslinked by branched, urethane group-containing linkages.

15. The method of claim 14 , wherein the urethane groups are part of an aryl group.

16. The method of claim 15 , wherein the crosslinked polytetrahydrofuran has the structure:

where n and m represent the number of repeat units in the polytetrahydrofuran chain and the crosslinked polytetrahydrofuran, respectively.

17. The method of claim 16 , wherein the strain induces the formation of microcrystalline domains in the crosslinked polyether polyol.

18. The method of claim 12 , wherein the electrically conductive particles are carbon particles.

19. The method of claim 18 , wherein the carbon particles comprise carbon nanotubes.

20. The method of claim 12 , wherein the strain decreases the electrical conductivity of the composite by a factor of at least 1000.

21. A method of sensing a strain, the method comprising:
exposing a composite to a strain, the composite comprising crosslinked polyether polyol and electrically conductive particles dispersed in the crosslinked polyether polyol, wherein the strain induces the formation of microcrystalline domains in the crosslinked polyether polyol.

22. A composite comprising: polytetrahydrofuran crosslinked with triphenymethane triisocyanate, the crosslinked polytetrahydrofuran having the structure:

where n and m represent the number of repeat units in the polytetrahydrofuran chain and the crosslinked polytetrahydrofuran, respectively; and
electrically conductive particles dispersed in the crosslinked polytetrahydrofuran.

23. The composite of claim 22 , wherein the electrically conductive particles are carbon particles.

Assignees

• Wisconsin Alumni Res Found

Inventors

• Gong Shaoqin
• Ma Zhenqiang
• Wang Yunming
• Mi Hongyi

Classifications

• G01B1/00

  Measuring instruments characterised by the selection of material therefor · CPC title

• C08K2201/011

  Nanostructured additives · CPC title

• C08K3/08

  Metals · CPC title

• C08L71/02

  Polyalkylene oxides · CPC title

• C08G18/7664

  containing alkylene polyphenyl groups · CPC title