Carbon nanotubes (CNTs) have attracted great interest because of their unique mechanical and electronic properties. They show a very high aspect ratio (length-to-diameter) and they have been shown to participate in applications such as in sensing, nanoelectronics and mechanical reinforcement of various matrices. However, manipulation and processing of CNTs has been limited by their insolubility in most common solvents, although some dissolution has recently been obtained.

The production of high volume fraction CNT films and tapes, the so called buckypapers, has opened the way for use of CNTs in practical applications. We produce buckypapers by oxidizing carbon nanotubes using chemical, electrochemical and plasma treatment. Stable aqueous CNT suspensions prepared by sonication are vacuum filtered through polymer membrane filters. After drying the CNT films are peeled off from the filtration membrane.

We grow forests of vertically aligned carbon nanotubes via Chemical Vapor Deposition (CVD) in an horizontal quartz tube that is housed in a 3-zone tubular furnace. Growth takes place under inert gas environment, with constant feed of the carbon precursor and catalyst on Si wafers. The morphology of the carpets, of a height of some millimeters, is examined by Scanning Electron Microscopy (SEM) while characterisation is performed via XRD and Raman. We impregnate the forests with polymers to create nanocomposite materials with unidirectional nanoreinforcement which we test in compression.

Researchers involved:
• Konstantinos Dassios

"System 1" consists of a 0.65m Spex 1877 Triple Micro-Raman Spectrometer equipped with a 1800gr/mm grating and a Wright Instruments Peltier-cooled CCD detector, a 5W (all lines) Argon Ion laser and a Jobin-Yvon miscoscope with polarizer/analyzer and Dilor confocal hole. A Melles-Griot XYZ microtranslator is employed for accurate Raman mapping with a 1 micrometer resolution. Three exciting wavelength are available: 488 nm, 514.5 nm, 632 nm.