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Viscoélasticité et structure de gels à base de chitosane - Relations avec les propriétés diffusionnelles de macromolécules dans ces biogels

Abstract : In this work, we study biogels of chemically crosslinked chitosan coils - a natural polyelectrolyte in the family of polysaccharides - in water. We have two related goals: characterizing the structure of the gels and understanding mass transport in it. Using mechanical spectroscopy measurements, we show that we can change the kinetics of formation and the structure of those hydrogels, according to the molecular weight and concentration of chitosan, the pH and the POE (polyoxyethylene) concentration. These results are confirmed by determining the correlation length between entanglement points of the hydrogel using neutron diffusion at small angles. We then study the diffusion of fluorescent dextran macromolecules according to their molecular weight in crosslinked and uncrosslinked chitosan using fluorescence recovery after photobleaching by interference pattern (FRAP). Noticing that the diffusion coefficient versus the molecular weight of dextran is a power law of exponent -1, we suggest a Rouse type diffusion. In chitosan gels, we clearly establish a difference between a solution type diffusion and a blocked dynamics when the molecular weight of dextran reaches a critical value.
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https://tel.archives-ouvertes.fr/tel-00011265
Contributor : Linda Payet <>
Submitted on : Saturday, December 24, 2005 - 7:19:25 PM
Last modification on : Thursday, March 4, 2021 - 4:21:46 PM
Long-term archiving on: : Saturday, April 3, 2010 - 6:51:21 PM

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  • HAL Id : tel-00011265, version 1

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Linda Payet. Viscoélasticité et structure de gels à base de chitosane - Relations avec les propriétés diffusionnelles de macromolécules dans ces biogels. Dynamique des Fluides [physics.flu-dyn]. Université Paris-Diderot - Paris VII, 2005. Français. ⟨tel-00011265⟩

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