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Title: Production, characterisation and properties of carbon nanotube fibres
Author: Sundaram, Rajyashree Meenakshi
ISNI:       0000 0004 2732 7257
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2012
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Assembling carbon nanotubes (CNTs) in to ensembles like fibres, yarns or films is aimed at exploiting the exceptional properties of individual CNTs at a macroscopic scale. Amongst the various production methods, continuous and direct spinning of CNT assemblies (specifically, fibres) from the gas-phase chemical vapour deposition (CVD) reactor is attractive due to its scale-up potential. Although, these fibres exhibit remarkable mechanical, electrical and thermal properties, their performance is limited by compositional heterogeneity – stemming from the presence of non-CNT inclusions and nanotubes with a wide distribution of diameters, lengths and chiralities. The work presented here attempts to explore strategies to control the composition of the CNT fibres. Reduction of impurity levels can stem to either post-spinning removal of extraneous materials or to direct synthesis of pure fibres. In this work, each of these routes has been pursued. A post-spinning purification methodology, involving sonication of the continuously spun fibres in a solvent has been attempted and the structure, composition and performance of the purified fibres have been assessed. In addition, having evaluated the origins of the compositional heterogeneity associated with the CVD-based synthesis employed for fibre spinning, CNT fibres with minimal impurities could be directly produced by coordinating the pyrolysis chemistry of the CVD-reactants. As a step further, morphology control of the constituent nanotubes, specifically with respect to limiting their diameter distribution and regulating the number of walls, was also attempted. As a result, CNT fibres composed of exclusively multiwalled/doublewalled/singlewalled nanotubes with minimal impurities have been produced. Having developed protocols to exercise a definite degree of control on the contents of the CNT fibres, effects of the composition on the fibre-performance have also been examined.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available