Printed stretchable strain sensor

Patent metadata

Field	Value
Publication number	US-10151649-B2
Application number	US-201415036937-A
Country	US
Kind code	B2
Filing date	Nov 17, 2014
Priority date	Nov 18, 2013
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

A printed stretchable strain sensor comprises a seamless elastomeric body and a strain-sensitive conductive structure embedded in the seamless elastomeric body. The strain-sensitive conductive structure comprises one or more conductive filaments arranged in a continuous pattern. A method of printing a stretchable strain sensor comprises depositing one or more conductive filaments in a predetermined continuous pattern into or onto a support matrix. After the depositing, the support matrix is cured to embed a strain-sensitive conductive structure in a seamless elastomeric body.

First claim

The invention claimed is:

1. A method of printing a stretchable strain sensor, the method comprising:
depositing one or more conductive filaments in a predetermined continuous pattern into or onto a support matrix; and
after the depositing, curing the support matrix to embed a strain-sensitive conductive structure in a seamless monolithic elastomeric body,
wherein a plateau value of shear elastic modulus G′ f of the conductive filament is from about 10 times to about 1000 times a plateau value of shear elastic modulus G′ s of the support matrix.

2. The method of claim 1 , wherein the support matrix is viscoelastic.

3. The method of claim 1 , wherein the support matrix comprises a fluid filler layer thereon, and wherein curing the support matrix further comprises curing the fluid filler layer.

4. The method of claim 3 , wherein the fluid filler layer comprises a strain-rate independent viscosity of no more than about 100 Pa·s.

5. The method of claim 1 , wherein a plurality of the strain-sensitive conductive structures are embedded in the seamless monolithic elastomeric body.

6. A method of printing a stretchable strain sensor, the method comprising:
depositing one or more sacrificial filaments comprising a fugitive ink in a predetermined continuous pattern into or onto a support matrix;
after the depositing, curing the support matrix to form a seamless monolithic elastomeric body,
removing the fugitive ink to create a continuous channel in the seamless monolithic elastomeric body; and
flowing a conductive fluid into the continuous channel, thereby embedding a strain-sensitive conductive structure in the seamless monolithic elastomeric body.

7. The method of claim 6 , wherein the fugitive ink is removed after curing the support matrix, upon cooling of the seamless monolithic elastomeric body.

8. The method of claim 6 , wherein the conductive fluid is selected from the group consisting of: eutectic gallium-indium alloys, mercury, dispersions of metal particles, ionic fluids, intrinsically conductive polymers and hydrogels, and polymer and hydrogel composites.

9. The method of claim 6 , wherein the one or more sacrificial filaments are deposited at a printing speed of from about 0.1 mm/s to about 100 mm/s.

10. The method of claim 6 , wherein the curing comprises applying UV light, heat, or a chemical curing agent.

11. The method of claim 6 , wherein the support matrix comprises a fluid filler layer thereon, and wherein curing the support matrix further comprises curing the fluid filler layer.

12. The method of claim 6 , wherein a plateau value of shear elastic modulus G′ f of the sacrificial filament is from about 10 times to about 1000 times a plateau value of shear elastic modulus G′ s of the support matrix.

13. The method of claim 6 , wherein a plurality of the strain-sensitive conductive structures are embedded in the seamless monolithic elastomeric body.

14. A method of printing a stretchable strain sensor, the method comprising:
depositing one or more conductive filaments in a predetermined continuous pattern into or onto a support matrix comprising a fluid filler layer thereon, the fluid filler layer comprising a strain-rate independent viscosity of no more than about 100 Pa·s; and
after the depositing, curing the support matrix and the fluid filler layer to embed a strain-sensitive conductive structure in a seamless monolithic elastomeric body.

Assignees

• Harvard College

Inventors

• Lewis Jennifer A
• Muth Joseph T
• Vogt Daniel M
• Truby Ryan L
• Menguc Yigit
• Kolesky David B
• Wood Robert J

Classifications

• G06F3/014

  Hand-worn input/output arrangements, e.g. data gloves · CPC title

• G01L1/2287 Primary

  constructional details of the strain gauges (adjustable resistors H01C10/00) · CPC title

• G01L1/20

  by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids (of piezo-resistive materials G01L1/18); by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress · CPC title

• G01L1/18

  using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material · CPC title