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dc.contributor.advisor Ngoepe, P.E. Kubai, Thomas
dc.contributor.other Ackermann, L. 2013-08-16T12:50:14Z 2013-08-16T12:50:14Z 2007
dc.description Thesis (MSc.) (Physics) --University of Limpopo, 2007 en_US
dc.description.abstract Molecular dynamics simulations have been carried out in order to examine the mechanism of diffusion of molecules in amorphous polymer matrix. PDMS model was folded in to a periodic cell, generated by rotational isomeric state (RIS) method at a prescribed temperature and density. Molecular dynamics was used to study transport properties of cyclic PDMS oligomers (hexa-methylcyclotrisiloxane (D3), octa-methylcyclotetrasiloxane (D4) and deca-methylcyclopentasiloxane (D5) using Dreiding and COMPASS force fields. Diffusion coefficients were calculated from the Einstein relation. Only D3 penetrant reached the long time limit from which the Einstein relation is satisfied. Analysis of displacement versus time for all the penetrants in PDMS matrix indicates that the penetrant motion is characterized by relatively long periods interspersed with fairly long and small jumps. Transport of solvent molecules occurs by jumps between individual sections of free volume (cavity/hole) through temporarily open channels. en_US
dc.description.sponsorship The National Research Foundation (NRF) and Eskom en_US
dc.format.extent viii, 85 leaves en_US
dc.language.iso en en_US
dc.publisher University of Limpopo (Turfloop Campus) en_US
dc.relation.requires pdf en_US
dc.subject Computer modelling studies en_US
dc.subject PDMS oligomer en_US
dc.subject PDMS polymer en_US
dc.subject.ddc 539.6 en_US
dc.subject.lcsh Plasma desorption mass spectrometry en_US
dc.subject.lcsh Mass spectometry en_US
dc.title Computer modelling studies of the diffusion of low moleculer weight cyclic PDMS oligomer in PDMS polymer en_US
dc.type Thesis en_US

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