Solventless coated carbon nanotube network
A method of coating a carbon nanotube material with a solventless coating composition is described. The resulting coating has been shown to preserve the conductivity of the conductive layer and protect the conductive layer from the effects of subsequent coating compositions. Examples are shown in which the coating formulation comprises a polyol and an isocyanate. A layer material comprising a polyurethane coating on a carbon nanotube network layer is also described.
1. A layered CNT-containing article, comprising:
a substrate;
a conductive CNT network layer disposed between the substrate and a polyurethane coating having a thickness of at least 0.250 μm;
wherein the polyurethane coating is in direct contact with the CNT layer;
and further wherein the underlying CNT network layer while in direct contact with the polyurethane coating has a sheet resistance of 120 Ω/square or less;
and wherein the layered CNT-containing article possesses anti-icing capability such that, if powered to at least 1.4 W/in 2 and exposed to a water spray at 0° F. and wind velocity of 70 mph for 15 minutes, the layered CNT-containing article does not experience icing.
2. The article of claim 1 wherein the underlying CNT network layer has a sheet resistance of 25 Ω/square or less.
3. The article of claim 1 wherein the underlying CNT network layer has a sheet resistance of 1 Ω/square or less.
4. The article of claim 1 wherein the CNT network layer is p-doped.
5. The article of claim 1 wherein the CNT network layer does not contain residual dispersing agent or surfactant.
6. The article of claim 1 wherein the combined CNT network layer and polyurethane coating consist essentially of CNTs and polyurethane.
7. The article of claim 1 wherein the polyurethane does not contain polyether moieties.
8. The article of claim 1 wherein the polyurethane does not contain any sulfate groups.
9. The article of claim 1 wherein the CNT layer comprises Nafion or hyaluronic acid.
10. The article of claim 1 wherein the polyurethane the underlying CNT layer maintains shielding effectiveness greater than 20 dB.
11. The article of claim 1 having a geometric surface area of at least 1 cm×1 cm.
12. An airplane wing comprising the article of claim 1 wherein the substrate comprises the surface of a wing.
13. The article of claim 1 wherein the CNT network layer comprises 50 mass % or less of the polymer coating within the layer.
14. A layered CNT-containing article, comprising:
a substrate;
a conductive CNT network layer disposed between the substrate and a polyurethane coating having a thickness of at least 0.250 μm;
wherein the polyurethane coating is in direct contact with the CNT layer;
further wherein the underlying CNT network layer while in direct contact with the polyurethane coating has a sheet resistance of 120 Ω/square or less;
wherein the CNT layer comprises hyaluronic acid;
and wherein the layered CNT-containing article possesses anti-icing capability such that, if powered to at least 1.4 W/in 2 and exposed to a water spray at 0° F. and wind velocity of 70 mph for 15 minutes, the layered CNT-containing article does not experience icing.
15. The article of claim 14 wherein the conductive CNT network layer has a thickness of 150 μm or less.
16. The article of any of claim 14 wherein the conductive CNT network layer has a thickness of 0.3 μm to 100 μm.
17. The article of claim 14 wherein the volume fraction of CNTs in the CNT network layer is between 2 and 90%.
18. The article of claim 14 wherein the conductive CNT network layer comprises at least 50 mass % CNTs.
19. The article of claim 14 wherein the polyurethane layer is made from a solventless mixture comprising a biobased polyol.