Printed stretchable strain sensor
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.
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.