Low porosity nanotube fabric articles
A method for controlling density, porosity and/or gap size within a nanotube fabric layer is disclosed. In one aspect, this can be accomplished by controlling the degree of rafting in a nanotube fabric. In one aspect, the method includes adjusting the concentration of individual nanotube elements dispersed in a nanotube application solution. A high concentration of individual nanotube elements will tend to promote rafting in a nanotube fabric layer formed using such a nanotube application solution, whereas a lower concentration will tend to discourage rafting. In another aspect, the method includes adjusting the concentration of ionic particles dispersed in a nanotube application solution. A low concentration of ionic particles will tend to promote rafting in a nanotube fabric layer formed using such a nanotube application solution, whereas a higher concentration will tend to discourage rafting. In other aspects, both concentration parameters are adjusted.
1. A nanotube fabric article, comprising:
at least one nanotube fabric layer, each of said at least one nanotube fabric layers comprising a plurality of nanotubes;
wherein at least a portion of said nanotubes within each of said at least one nanotube fabric layers includes randomly oriented rafted bundles of nanotubes; and
wherein each of said at least one nanotube fabric layers is free of voids larger than a preselected size; and
wherein said at least one nanotube fabric layer further comprises ionic organic species, ionic polymers, inorganic salts, or mixtures thereof.
2. The nanotube fabric article of claim 1 wherein said preselected size is within the range of 10 nanometers to 50 nanometers.
3. The nanotube fabric article of claim 1 wherein at least 10% of said nanotubes within each of said at least one nanotube fabric layers are rafted.
4. The nanotube fabric article of claim 1 wherein at least 20% of said nanotubes within each of said at least one nanotube fabric layers are rafted.
5. The nanotube fabric article of claim 1 wherein at least 30% of said nanotubes within each of said at least one nanotube fabric layers are rafted.
6. The nanotube fabric article of claim 1 wherein at least 40% of said nanotubes within each of said at least one nanotube fabric layers are rafted.
7. The nanotube fabric article of claim 1 wherein said preselected size is selected to provide a desired sheet resistance within said nanotube fabric article.
8. The nanotube fabric article of claim 7 wherein said sheet resistance is within the range of 1 k-Ohm/square to 1 M-Ohm/square.
9. The nanotube fabric article of claim 7 wherein said sheet resistance is within the range of 10 k-Ohm/square to 100 k-Ohm/square.
10. The nanotube fabric article of claim 1 wherein said inorganic salts include silica.
11. The nanotube fabric article of claim 1 wherein said at least one nanotube fabric layer further comprises at least one additional carbon allotrope.
12. The nanotube fabric article of claim 11 wherein said at least one additional carbon allotrope includes amorphous carbon.
13. The nanotube fabric article of claim 1 wherein said nanotubes are carbon nanotubes.
14. The nanotube fabric article of claim 13 wherein said carbon nanotubes include single walled nanotubes.
15. The nanotube fabric article of claim 13 wherein said carbon nanotubes include multi walled nanotubes.
16. The nanotube fabric article of claim 13 wherein said carbon nanotubes are a mixture of single walled nanotubes and multi walled nanotubes.
17. The nanotube fabric article of claim 13 wherein said carbon nanotubes are functionalized carbon nanotubes.
18. The nanotube fabric article of claim 1 wherein said nanotubes are solution deposited nanotubes.
19. The nanotube fabric article of claim 1 wherein said nanotubes are of a uniform length.
20. The nanotube fabric article of claim 1 wherein said nanotubes have a selected distribution of lengths.