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Etude des effets de confinement dans la silice mésoporeuse et dans certaines nanostructures carbonées.

Abstract : Physico-chemical properties of materials can be strongly modified by confinement because of the quantum effects that appear at such small length scales and also because of the effects of the confinement itself. The aim of this thesis is to show that both the nature of the confining material and the size of the pores and cavities have a strong impact on the confined material. We first show the effect of the pore size of the host mesoporous silica on the temperature of the solid-solid phase transition of silver selenide, a semiconducting material with enhanced magnetoresistive properties under non-stoichiometric conditions. Narrowing the pores from 20 nm to 2 nm raises the phase transition temperature from 139oC to 146oC. This result can be explained by considering the interaction between the confining and confined materials as a driving force. The effects of confinement are also studied in the case of hydrogen and deuterium inside cavities of organized carbon nanostructures. The effects that appear in the adsorption/desorption cycles are much stronger with carbon nanohorns as the host material than with C60 peapods and single-walled carbon nanotubes.
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https://tel.archives-ouvertes.fr/tel-00107124
Contributor : Vincent Leon <>
Submitted on : Tuesday, September 9, 2008 - 5:31:09 PM
Last modification on : Thursday, March 5, 2020 - 6:48:58 PM
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  • HAL Id : tel-00107124, version 2

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Vincent Leon. Etude des effets de confinement dans la silice mésoporeuse et dans certaines nanostructures carbonées.. Matériaux. Université d'Orléans, 2006. Français. ⟨tel-00107124v2⟩

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