Irreversible hardening of a colloidal gel under shear: The smart response of natural rubber latex gels

De Oliveira Reis Guilherme, Gibaud Thomas, Saint-Michel Brice, Manneville Sébastien, Leocmach Mathieu, Vaysse Laurent, Bonfils Frédéric, Sanchez Christian, Menut Paul. 2019. Irreversible hardening of a colloidal gel under shear: The smart response of natural rubber latex gels. Journal of Colloid and Interface Science, 539 : 287-296.

https://doi.org/10.1016/j.jcis.2018.12.031

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Quartile : Q1, Sujet : CHEMISTRY, PHYSICAL

Résumé : Natural rubber is obtained by processing natural rubber latex, a liquid colloidal suspension that rapidly gels after exudation from the tree. We prepared such gels by acidification, in a large range of particle volume fractions, and investigated their rheological properties. We show that natural rubber latex gels exhibit a unique behavior of irreversible strain hardening: when subjected to a large enough strain, the elastic modulus increases irreversibly. Hardening proceeds over a large range of deformations in such a way that the material maintains an elastic modulus close to, or slightly higher than the imposed shear stress. Local displacements inside the gel are investigated by ultrasound imaging coupled to oscillatory rheometry, together with a Fourier decomposition of the oscillatory response of the material during hardening. Our observations suggest that hardening is associated with irreversible local rearrangements of the fractal structure, which occur homogeneously throughout the sample.

Mots-clés Agrovoc : Hevea brasiliensis, latex, caoutchouc, gel, propriété rhéologique

Mots-clés libres : Isotropic particles, Strain stiffening-hardening, Mechano-responsive gels, Natural rubber

Classification Agris : Q60 - Traitement des produits agricoles non alimentaires

Champ stratégique Cirad : CTS 7 (2019-) - Hors champs stratégiques

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