Continuous harvesting of intact carbon nanotube arrays - 1653 and 1873
- *Abstract
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Overview
Aligned carbon nanotubes have applications in areas ofcomposite materials (separation/purification media, catalysts, catalyst supports), energy storage and transfer, and electronics (flat panel TVs, cellular phones,sensors, electronically conductive plastics).
We have previously shown that multi-walled carbon nanotubes (MWCNTs) can be grown in a "wheat field" layout where vertically-aligned MWCNTs are arrayed perpendicular to an underlying substrate (U.S. patents 7,160,531 and 7,504,078). In the past, the MWCNTs have been harvested from the substrate for subsequent use in processing with hand-held razors positioned at various acute angles to the substrate. Unfortunately, tight scrolling (inner rolling diameters of less than 2-3 mm) of the array normally occurs during such a procedure and only small pieces (less than 1 inch squared) are typically recoverable. We have now developed a method for continuous harvesting of the MWCNTs that allows them to be harvested intact and in much larger sections.
Invention
UK researchers are developing an apparatus to harvest a carbon nanotubearray from a substrate in continuous manner. This apparatus consists of a peeler that peels the carbon nanotube arrayaway from the substance, a support that receives the carbon nanotube array, anda drawing device that simultaneously draws carbon array from the substrate ontoa support. Also, a continuous conveyoris provided for continuous harvesting, to maintain the synchronicity betweenthe feeder, the peeler, and the support in the form of winding drum. This synchronous operation allows productionof large sections of carbon nanotubes array in intact manner, which was notachieved by traditional methods that resulted in a distorted, “scrolled” sheetof MWCNTs.
Our harvested carbon nanotube arrays include MWCNTsforming free-standing films—free from the underlying substrate—with thevertically aligned, “wheat field” morphology intact. Furthermore, the arrays produced by ourmethod are relatively large (about 100 and about 500 inches squared) whencompared to those harvested by traditional methods (about 1 inch squared).
Applications
- composite materials
- energy storage and transfer
- electronic devices
Advantages
- continuous production of vertically-aligned, intact, non-scrolled, flat MWCNT arrays of more than 100 square inches
- maintains thethrough-thickness axial alignment of the MWCNTs within the array in afree-standing sheet form, un-bound to the original growth substrate
- MWCNT sheets provide for preferential transport properties, including thermalconductivity, along the nanotube axes, or through the sheet thickness
- MWCNT sheets have both upper and lower MWCNT tips exposed
- MWCNT sheetsare compliant and can conform to surface roughness within an interfaceapplication
- original MWCNT growth substrates can be re-used
- free-standing MWCNT sheets can be die-cut into predetermined shapes
IP Status: U.S. Patent No. 9,533,883
- Country/Region
- USA
