M.Sc. / Carbon nanotubes are among the most exciting new materials being investigated and synthesized, owing to their outstanding mechanical, electronic and optical properties. For more than a decade, the translation of these properties into realistic applications has been hindered by solubility and processing difficulties. Recently the development of efficient methodologies for covalent chemical modification has raised hope for the use of these materials in various fields of application such as biosensors, vaccine and drug delivery systems, medical imaging, biomaterials, water purification, etc... Phosphorylation of functionalized and unfunctionalized multiwalled carbon nanotubes (MWCNTs) is reported in this dissertation. This was achieved by the incorporation of phosphorus moieties on the end and side walls of the MWCNTs. Pristine MWCNTs were functionalized through oxidation by sodium hypochlorite and with a mixture of sulphuric and nitric acids, a diazonium coupling method and by reduction of amide functions on the surface of MWCNTs. Then condensation reactions with alkyl or aryl chlorophosphates were undertaken to obtain compounds 7 to 12. Phosphorylation of pristine MWCNTs was achieved by a 1, 3 dipolar cyclo addition of diphenyl phosphoryl azide. Characterization of the phosphorylated multiwalled carbon nanotubes has been performed by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy X-Ray Dispersive Spectroscopy (EXDS), Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) and Raman Spectroscopy. These techniques together gave evidence for surface, structure and chemical modifications of the synthesized material.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:8362 |
| Date | 07 May 2009 |
| Creators | Ndzimandze, Thembinkosi Mpendulo |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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