Continuous, scalable deposition of aligned carbon nanotubes using sprays of carbon nanotube solutions
A system for producing a layer of aligned carbon nanotubes, the system comprising: a sprayer, a solution delivery tube configured to deliver a carbon nanotube solution to the sprayer, and a reservoir configured to contain a subphase. The sprayer is configured to generate a continuous spray of the carbon nanotube solution. The continuous floating layer is supported by the subphase. The spray of carbon nanotube solution includes droplets of the carbon nanotube solution, the droplets having a median diameter in a range from about 1 to about 100 microns. The sprayer maintains the continuous floating layer of carbon nanotube solution on the subphase as a substrate is inserted into or removed from the subphase, the carbon nanotube solution being in contact with the substrate.
1. A method of depositing a layer of aligned carbon nanotubes on a substrate, the method comprising:
providing a reservoir having a water subphase contained therein;
generating a continuous spray of a carbon nanotube solution from a sprayer to form a continuous floating layer of the carbon nanotube solution supported on the subphase, wherein the carbon nanotube solution includes carbon nanotubes dispersed in chloroform and the spray of the carbon nanotube solution includes droplets, the droplets having a median diameter in a range from about 1 to about 100 microns; and
removing or inserting a substrate from or into, respectively, the subphase, the continuous floating layer of the carbon nanotube solution being in contact with the substrate, the sprayer maintaining the continuous floating layer of carbon nanotube solution on the subphase as the substrate is inserted into or removed from the subphase to thereby form a layer of aligned carbon nanotubes on the substrate.
2. The method of claim 1 , wherein removing or inserting the substrate from or into the subphase includes moving an actuator holding the substrate so that the substrate is inserted into or removed from the subphase, respectively, as the sprayer maintains a continuous floating layer of the carbon nanotube solution on the subphase.
3. The method of claim 1 , wherein removing or inserting the substrate from or into the subphase includes moving a lift table supporting the reservoir so that the substrate is inserted into or removed from the subphase, respectively, as the sprayer maintains a continuous floating layer of the carbon nanotube solution on the subphase.
4. The method of claim 1 , wherein removing or inserting the substrate from or into the subphase includes pumping the subphase into or out of the reservoir, via a pump fluidly connected to the reservoir, so that the substrate is inserted into or removed from the subphase, respectively, as the sprayer maintains a continuous floating layer of the carbon nanotube solution on the subphase.
5. The method of claim 1 , wherein generating the continuous spray of the carbon nanotube solution includes spraying from a sprayer configured as an ultrasonic atomizer.
6. The method of claim 1 , wherein generating the continuous spray of the carbon nanotube solution includes spraying from a sprayer configured as an electro-sprayer.
7. The method of claim 1 , wherein generating the continuous spray of a carbon nanotube solution includes passing the carbon nanotube solution through a nozzle along with high pressure compressed air to form an aerosol of the carbon nanotube solution.
8. The method of claim 1 , generating the continuous spray of the carbon nanotube solution includes controlling a dose of the carbon nanotubes in contact with the substrate by varying the rate at which the sprayer sprays the carbon nanotube solution or by varying a concentration of the carbon nanotube solution.
9. The method of claim 1 , further including rolling up the substrate on which the layer of aligned carbon nanotubes is deposited.
10. The method of claim 1 , wherein the layer of aligned carbon nanotubes covers an area of the substrate in a range from about 90 percent to about 100 percent of a total area of the substrate.
11. The method of claim 1 , wherein the sprayer is positioned a distance from substrate in a range of about 1 mm about 20 mm.
12. The method of claim 1 , wherein the continuous floating layer of carbon nanotube solution on the subphase has a thickness in a range from about 0.01 to about 1 mm.