| Growth of nanotubes has been investigated using thermal chemical vapor deposition in a template containing catalyst nanoparticles. Various parameters are found sensitive to growth; of which the size and morphology of catalyst nanoparticles is one of the major parameter. In the first part of research, unlike the usual method of patterning or sputtering of thin film catalyst, substrates with embedded catalyst were prepared using ion implantation. The developments of used catalyst and the resulting nanotube were studied as a function of ion doses. It was found that increase in particle size resulted in the formation of nanotube of bigger size.;Finally, ion irradiation technique was successfully used in polymer nanocomposites, where the defects were introduced in nanotubes before composite formation. The defect dynamics and hence the interaction behavior of randomly dispersed nanotubes polymer composites were investigated with Thermogravimetric analysis, Differential scanning calorimetry, Raman spectroscopy and Electron spin resonance. The results from these techniques indicate that at low number of defects not only the interaction between filler and matrix increases, but also enhances the thermal stability of the composites. Based on the experimental evidences, a model is proposed to explain the change in thermal stability.;The second part of this work is devoted on nanotube modification using high-energy ions and the corresponding thermal oxidation study. The oxidation behaviors were monitored as a function of different irradiated ions and different doses. Observation showed that smaller doses of ions, particularly for hydrogen and helium, could be used to modify the nanotubes with enhanced thermal stability without structural degradation. Based on the theoretical investigation from various group, such irradiation-mediated improvements of the thermal stability is believed due to cross-linking between CNTs or between nanotube and impurities present in the sample. |
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