Stretchable electrically conductive ink compositions
Disclosed herein are stretchable conductive ink compositions comprising a polymer, conductive flake, an additive, and optionally conductive beads, wherein the initial resistivity is measured before elongation, and wherein the resistivity at 50% elongation is about 10 times or less of the initial resistivity.
1. A stretchable conductive ink composition comprising:
a polymer,
conductive flake,
conductive beads, and
an additive,
wherein initial resistivity is measured before elongation,
wherein the resistivity at 50% elongation is no more than about 10 times the initial resistivity, and
wherein the additive and the polymer have a difference in solubility parameter greater than about 2;
wherein the ratio of conductive flake to conductive bead is in the range of about 98:2-55:95 by volume.
2. The stretchable conductive ink of claim 1 , wherein the conductive flake comprises silver, aluminum, carbon, nickel, copper, graphite, or a combination thereof.
3. The stretchable conductive ink of claim 2 , wherein conductive flake is silver flake.
4. The stretchable conductive ink of claim 1 , wherein the resistivity at about 100% elongation is less than about 100 Ohm*cm.
5. The stretchable conductive ink of claim 4 , wherein the resistivity at 100% elongation is 1×10 −4 Ohm-cm.
6. The stretchable conductive ink of claim 1 , wherein the initial resistivity is in the range of about 1×10 −3 to about 1×10 −5 Ohm*cm.
7. The stretchable conductive ink of claim 1 , wherein the additive is a plasticizer, coupling agent, or a surfactant.
8. The stretchable conductive ink of claim 1 , wherein the conductive flake is present in the composition in an amount of about 20% to about 90% by volume.
9. The stretchable conductive ink of claim 1 , wherein the additive is present in the composition in an amount from about 0.01% to about 10% by volume.
10. The stretchable conductive ink of claim 9 , wherein the additive is present in the composition in an amount from about 0.10% to about 0.3% by volume.
11. The stretchable conductive ink of claim 1 , wherein the polymer is a thermoplastic polyurethane.
12. The stretchable conductive ink of claim 1 , wherein the additive is a titanate coupling agent or a zirconate coupling agent.
13. The stretchable conductive ink of claim 1 , wherein the additive is Titanium IV tetrakis(bis 2-propenolato methyl)-1-butanolato adduct 2 moles (di-tridecyl)hydrogen phosphite.
14. The stretchable conductive ink of claim 1 , wherein conductive bead is silver bead.
15. The stretchable conductive ink of claim 1 , wherein the resistivity is less than 10 6 Ohms when elongation reaches greater than about 50%.
16. The stretchable conductive ink of claim 1 , wherein the conductive bead has a diameter of less than 1 μm.
17. The stretchable conductive ink of claim 1 , wherein the conductive bead has an aspect ratio of about 1.
18. The stretchable conductive ink of claim 1 , further comprising an organic solvent.