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Etude Structurale et Dynamique de Solutions de Sucre Confinées

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par Gérald LELONG
Université d'Orléans - Thèse 2007

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Even though the active role of sugar molecules is well known as stabilizer agent for cell membranes upon dehydration, the responsible process is still unidentified. Nevertheless, the great affinity existing between sugar and water molecules -- evidenced by the important number of hydrogen bondings between these two species -- seems to be the main agent at the origin of this exceptional property. An experimental study of sugar and water molecules should allow to determine accurately the interactions causing this remarkable resistance.

In this work, we focused on solutions of mono- and disaccharides (glucose, fructose and trehalose). The quasi-elastic neutron scattering is an appropriate tool to probe, at the picosecond timescale, the dynamics of water and sugar in solution and under confinement in porous materials presenting a scale mimicking the living world. Two matrices have been chosen : silica gel and mesoporous silica spheres presenting pores of 18 and 3 nm respectively. Both have been characterized with a large set of experiments (SANS, SEM, TEM, Raman Spectroscopy, BET, XRD). The effect of the confinement on the dynamics and solid-liquid transitions have been explored, thus an in-situ dehydration study monitored by small-angle neutron scattering allowed us to better understand the bioprotective effect of theses sugars.

KEYWORDS : Sugars, mono- and disaccharides, aqueous solution, synthesis, silica, gel, mesoporous spheres, MCM-41, confinement, molecular dynamics, phase transition, QENS, SANS.

DISCIPLINE : Physique, mention Physique et Physico-chimie de la matière et des matériaux

LABORATOIRE : Centre de Recherche sur la Matière Divisée

1b, Rue de la Férollerie 45071 Orléans Cedex 2 France

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