Silver nanowire and noble-metal coated silver nanowire conductive polymer composites with low loading percolation conduction
Composite materials with noble metal coated silver nanowires loaded into polymer are described. The composite materials may have resistivities of no more than about 100 Ohm-cm, or from about 100 Ohm-cm to about 1×10 11 Ohm-cm depending on the amount of noble metal coated silver nanowires loaded into the polymer. The noble metal coated silver nanowires may be platinum coated silver nanowires. Metal particulates such as silver flakes or silver particles may be added to the composite materials in order to obtain desired properties. Composite precursor compositions and methods for preparing the composite materials are described.
1. A composite material comprising noble metal coated silver nanowires and a polymer matrix combined to form the composite material, the composite material having a resistivity of no more than about 1 Ohm-cm and less than about 10 wt % platinum coated silver nanowires.
2. The composite material of claim 1 having from about 0.01 wt % to about 10 wt % platinum coated silver nanowires.
3. The composite material of claim 1 wherein the platinum coated silver nanowires have an average diameter of 100 nm or less.
4. The composite material of claim 3 wherein the platinum coated silver nanowires occupy no more than about 2.5 vol % of the composite material.
5. The composite material of claim 1 wherein the polymer matrix comprises at least about 90 wt % of the composite material.
6. The composite material of claim 1 wherein the composite material further comprises other metal particulates in an amount no more than about the weight of the platinum coated silver nanowires.
7. The composite material of claim 1 wherein the concentration of platinum coated silver nanowires is no more than about 2.0 wt %.
8. The composite material of claim 1 wherein the concentration of platinum coated silver nanowires is no more than about 0.1 wt %.
9. A heater comprising two bus bars of opposite polarity and a composite material, wherein the composite material is in contact with the bus bars such that current flows between the bus bars when a voltage is applied, and wherein the composite material comprises noble metal coated silver nanowires and a polymer matrix combined to form the composite material and has a resistivity of no more than about 1×10 11 Ohm-cm.
10. The heater of claim 9 wherein the composite material has a resistivity of no more than about 100 Ohm-cm.
11. The heater of claim 9 wherein the composite material has a resistivity of no more than about 1 Ohm-cm.
12. The heater of claim 9 wherein the composite material comprises from about 0.01 wt % to about 40 wt % noble metal coated silver nanowires.
13. The heater of claim 9 wherein the composite material comprises from about 0.1 wt % to about 20 wt % noble metal coated silver nanowires.
14. The heater of claim 9 wherein the composite material comprises no more than about 10.0 wt % noble metal coated silver nanowires.
15. The heater of claim 9 wherein the noble metal coated silver nanowires occupy no more than about 2.5 vol % of the composite material.
16. The heater of claim 9 wherein the noble metal coated silver nanowires have an average diameter of 100 nm or less.
17. The heater of claim 9 wherein the noble metal coated silver nanowires comprise platinum coated silver nanowires.
18. The heater of claim 9 wherein the noble metal coated silver nanowires comprise platinum coated silver nanowires, and the composite material comprises from about 0.5 wt % to about 10 wt % of the platinum coated silver nanowires.
19. The heater of claim 9 wherein the polymer matrix comprises at least about 90 wt % of the composite material.
20. The heater of claim 9 wherein the composite material comprises a coating and the heater further comprises a polymer overcoat on the coating.
21. The heater of claim 9 wherein the heater has a transmittance value of at least about 90%.
22. The heater of claim 9 wherein the noble metal coated silver nanowires exhibit a power per area greater than about 0.5 W/cm 2 (2000 W/m 2 ).