Abstract
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.