This thesis describes an investigation of various polymer/nanotube composite systems, using computer simulation. Firstly, pure polymer melts composed of linear homopolymers, polyethylene (PE) and poly(ethylene oxide) (PEO), were studied by a multiscale modelling approach. A Monte Carlo coarse-grained lattice model was employed to generate initial equilibrated chain configurations. A process of ‘reverse-mapping’ was then used to recover atomistic details from the coarse-grained model. After that, fully atomistic molecular dynamic (MD) simulations have been performed on samples of PE and PEO melts. Our results suggest good agreement of structural and dynamical properties between current MD results and experimental and theoretical results. Next, we discussed the application of this multiscale modelling approach to the study of PE/CNT (carbon nanotube) composite system. The presence of CNT causes a clear structuring of the polymer chains around the nanotube surface. Furthermore, structural relaxations of the interfacial PE chains were found to be slower than that of the pure PE melt. MD method and effective fibre theory were used for the calculation of composite mechanical properties, and results agree with experimental data. Finally, we attempted to study the organic/inorganic interface. A composite model containing an inorganic TiO<sub>2</sub> nanotube embedded in a PEO matrix was generated and results are compared with the PEO/CNT system. Much stronger structuring and ordering of PEO chains were found in the vicinity of the TiO<sub>2</sub> surface. In addition, the PEO conformation was more coiled in order to better adapt to the TiO<sub>2</sub> nanotube. Evidence for chain immobilization is more obvious in the PEO/TiO<sub>2</sub> system, which contributes to the improvement of interfacial properties of the composite.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:603639 |
| Date | January 2009 |
| Creators | Han, Y. |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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