In U.S. Patent Application 20100173228, University of Wollongong (Wollongong, AU) scientists Gordon George Wallace and Andrew Ian Minett detail a method of making carbon nanotube and carbon layer nanostructured composites.
Their invention relates to nanostructured composites comprising a nanotube network which is at least partially embedded within a carbon layer. It particularly relates to conducting nanostructured composites for use in the fields of energy conversion, energy storage and also the biomedical field. It also relates to a process via chemical vapor deposition (CVD) of carbon onto a catalyst layer on a substrate.
The composites and composite substrate structures are suitable for a variety of applications. In particular, the embodiment in which the nanocomposite is conducting makes it suitable for use in the fields of energy conversion and storage and in materials and devices that require conducting high surface area materials, such as electrodes for capacitors, hybrid battery/capacitors, supercapacitors, batteries, fuel cells, electrocatalysts, gas storage mediums, sensors, actuators, electromechanical actuators, photoelectrochemical solarcells and/or bioelectodes for electrical stimulation of cells and tissue.
FIG. 2. High resolution scanning electron microscopy images of the CNT-AC intersection region, showing intimate contact between the outer nanotube shell and the amorphous carbon layer (left image). Right image is a higher magnification image of one region in the left image, which suggests that the CNT is growing out through the AC layer and not merely on top of it.
FIG. 10. Scanning Electron Micrograph (SEM) images of CNT modified carbon fiber paper, showing a dense entanglement of carbon nanotubes which entirely covers the individual carbon fibers whilst still retaining the microporous nature of the host carbon fiber paper; (b) higher resolution image of the carbon fibre indicated in (a); inset (c) Transmission Electron Microscopy (TEM) image of an individual multi-wall carbon nanotube grown on the CFP.
FIG. 14. SEM images of CNT nanoweb deposited on a platinum sheet.
The nanotubes are oriented in the composite such that they protrude from the carbon layer. The nanotubes are partially embedded in the carbon layer, that is, a portion of one end of the nanotube is embedded in the carbon layer and the remaining portion of the nanotube protrudes from the carbon layer. In other words the nanotubes grow from the metal nanoparticles formed by reduction of the organic metal catalyst which is embedded in the carbon layer to form intimate connection between the nanotubes and the carbon layer. The nanocomposite is prepared via a process involving a metal catalyst deposited on a substrate. In the process, the metal nanoparticles of the catalyst become embedded in the carbon layer and it may be said that the nanotubes grow from these metal nanoparticles, resulting in intimate connection between the nanotubes and the carbon layer.