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Modelling of Rheological Properties of Carbon Nanotube Suspensions

Abstract : Single-walled carbon nanotubes (SWNTs) are frequently diluted in solvents with the aim of purify, functionalize and transform them. Control and optimization of those processes in liquid phase require a deep understanding of the rheology of SWNT suspensions. However, there is no consensus about the physical origin of some rheological signatures exhibited by the SWNT suspensions. This thesis is intended to elucidate this question by modelling the linear viscoelastic behaviour of SWNT dilute suspensions by using a Brownian Dynamics (BD) approach. Individual treated SWNT are modelled as semi-flexible filaments with a naturally curved structure due to the existence of side-wall defects. Continuous semi-flexible filament model is discretized as a non-freely jointed multi-bead-rod system with a non-straight configuration at equilibrium. A mechanical coherent re-definition of the discrete bending potential is proposed in order to tackle the naturally bent configurations. The linear viscolastic response of the SWNT-coarse-grained model in dilute suspension is BD-simulated under dynamic and relaxation functions. New relaxation processes, characterised by the activation of a mild elasticity at intermediate frequencies, are observed in the dynamic test mode. On the other hand, a quasi-instantaneous shear-modulus relaxation is obtained after the application of a shear-strain step. Bending-energy relaxation spectra are consistent with the range of dynamic responses proving the consistence of the model in the linear viscoelastic regime. The non-negligeble differences found with respect to the rheological behaviour of naturally straight systems demonstrates that the bending flexibility coupled with the presence of structural bent defects plays an important role on the dynamics of individual SWNTs in suspension.
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https://pastel.archives-ouvertes.fr/pastel-00552038
Contributor : Camilo Andrés Cruz Bernal <>
Submitted on : Wednesday, January 5, 2011 - 11:26:01 AM
Last modification on : Friday, July 17, 2020 - 2:54:12 PM
Long-term archiving on: : Saturday, December 3, 2016 - 1:45:47 AM

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  • HAL Id : pastel-00552038, version 1

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Camilo Andrés Cruz Bernal. Modelling of Rheological Properties of Carbon Nanotube Suspensions. Materials. Arts et Métiers ParisTech, 2010. English. ⟨NNT : 2010ENAM0046⟩. ⟨pastel-00552038⟩

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