Printed stretch sensor
Disclosed is a patterned article comprising: (1) a deformable nonconductive substrate; (2) an imagewise pattern thereon of a conductive stretchable ink; and (3) an external circuit connecting the imagewise pattern, the external circuit being capable of measuring the electrical resistance across regions of the deformable nonconductive substrate and determining the degree of deformation thereof.
1. A patterned article comprising:
(1) an elastomeric nonconductive substrate having a resistivity of at least 1.8×10 5 Ωm and an elasticity in the direction of elongation of at least 0.0008 MPa;
(2) an imagewise pattern comprising an electrically conductive stretchable ink on the substrate; and
(3) an external circuit electrically connected to the imagewise pattern, wherein the external circuit measures electrical resistance across a predetermined region of the elastomeric nonconductive substrate, wherein a user touching a surface portion of the elastomeric nonconductive substrate causes a thus-touched surface portion of the elastomeric nonconductive substrate to deform into a sphere, enabling the thus-touched substrate surface portion to function as a touch sensor.
2. An article according to claim 1 , wherein the elastomeric nonconductive substrate is selected from neoprene rubber, butyl rubber, styrene-butadiene rubber, silicon rubber, nitrile rubber, ethylene propylene rubber, ethylene propylene diene rubber, epichlorohydrin rubber, polyacrylic rubber, ethylene-vinyl acetate, polyether block amides, polysulfide rubber, chlorosulfonated polyethylene, or mixtures thereof.
3. An article according to claim 1 , wherein the electrically conductive stretchable ink includes a fluoroelastomer.
4. An article according to claim 1 , wherein the electrically conductive stretchable ink includes an electrically conductive pigment selected from carbon black, polypyrrole, polyacetylene, polyaniline, polyphenylene vinylene, polythiophene, polyphenylene sulfide, graphene, silver nanoparticles, copper nanoparticles, or mixtures thereof.
5. An article according to claim 1 , wherein the imagewise pattern further comprises:
(a) a first set of at least two non-crossing lines of an electrically conductive stretchable ink on a first surface of the elastomeric nonconductive substrate; and
(b) a second set of at least two non-crossing lines of an electrically conductive stretchable ink on a second surface of the elastomeric nonconductive substrate;
wherein at least one of the first set of lines on the first surface of the elastomeric nonconductive substrate cross at least one of the second set of lines on the second surface of the elastomeric nonconductive substrate; and
wherein the external circuit connected to the imagewise pattern enables determination of the location of the thus-touched surface portion of the elastomeric nonconductive substrate functioning as the touch sensor.
6. An article according to claim 5 , wherein the elastomeric substrate is selected from neoprene rubber, butyl rubber, styrene-butadiene rubber, silicon rubber, nitrile rubber, ethylene propylene rubber, ethylene propylene diene rubber, epichlorohydrin rubber, polyacrylic rubber, ethylene-vinyl acetate, polyether block amides, polysulfide rubber, chlorosulfonated polyethylene, or mixtures thereof.
7. An article according to claim 5 , wherein the electrically conductive stretchable ink on the first or second surface of the elastomeric nonconductive substrate includes a fluoroelastomer.
8. An article according to claim 5 , wherein the electrically conductive stretchable ink on the first or second surface of the elastomeric nonconductive substrate includes an electrically conductive pigment selected from carbon black, polypyrrole, polyacetylene, polyaniline, polyphenylene vinylene, polythiophene, polyphenylene sulfide, graphene, silver nanoparticles, copper nanoparticles, or mixtures thereof.
9. An article according to claim 1 , wherein the electrically conductive stretchable ink has a conductivity of from about 0.010 μS to 100 MS and comprises a fluoroelastomer.
10. An article according to claim 1 , wherein the elastomeric nonconductive substrate has a resistivity of at least 100 MΩm; or
wherein the elastomeric nonconductive substrate has a resistivity of at least 1 GΩm; or
wherein the elastomeric nonconductive substrate has a resistivity of at least 100 GΩm.
11. An article according to claim 1 , wherein the elastomeric nonconductive substrate has an elasticity in the direction of deformation at least 0.001 MPa.
12. An article according to claim 1 , wherein the elastomeric nonconductive substrate has an elasticity in the direction of deformation at least 0.01 MPa.
13. An article according to claim 1 ,
wherein the elastomeric nonconductive substrate is selected from the group consisting of silicon rubber, polyacrylic rubber, butyl rubber, and neoprene rubber;
wherein the imagewise pattern comprising an electrically conductive ink on the substrate is an imaged substrate; and
wherein the imaged substrate can be stretched in one axial direction to at least 110% at least 50 times without exhibiting cracks or delamination.
14. An article according to claim 1 ,
wherein the elastomeric nonconductive substrate is selected from the group consisting of silicon rubber, polyacrylic rubber, butyl rubber, and neoprene rubber;
wherein the imagewise pattern comprising an electrically conductive ink on the substrate is an imaged substrate; and
wherein the imaged substrate can be stretched in one axial direction to at least 150% at least 50 times without exhibiting cracks or delamination.
15. An article according to claim 1 , wherein the electrically conductive stretchable ink includes a fluoroelastomer; and
wherein the fluoroelastomer has a tensile strength of at least 3 MPa.
16. An article according to claim 1 , wherein the electrically conductive stretchable ink includes a fluoroelastomer; and
wherein the fluoroelastomer has an elongation at break of at least 150%.
17. An article according to claim 1 , wherein the electrically conductive stretchable ink is a material that contains substantially no silver nanoparticles.
18. An article according to claim 1 , wherein the electrically conductive stretchable ink is a material that contains substantially no copper nanoparticles.
19. An article according to claim 1 , wherein the imagewise pattern comprising an electrically conductive stretchable ink has a tensile strength of at least 3 MPa; or
wherein the imagewise pattern comprising an electrically conductive stretchable ink has a tensile strength of at least 8 MPa.
20. An article according to claim 1 , wherein the imagewise pattern comprises at least one loop in a resistance measuring circuit;
wherein by sampling the resistance in each loop it is determined which loops are experiencing peak resistance; and
wherein by using two sets of loops, one for the X-coordinate and one for the Y-coordinate, one can pinpoint the exact location of the touch.