Aging of cornstarch particles suspended in aqueous solvents at room temperature, Christophe Kusina, Wilbert J. Smit, Jean-Baptiste Boitte, Odile Aubrun, and Annie Colin Phys. Rev. E 103, 052609 (2021)

Aging of cornstarch particles suspended in aqueous solvents at room temperature, Christophe Kusina, Wilbert J. Smit, Jean-Baptiste Boitte, Odile Aubrun, and Annie Colin Phys. Rev. E 103, 052609 (2021)

https://journals.aps.org/pre/pdf/10.1103/PhysRevE.103.052609

Résumé :

Starch suspensions are often used as model systems to demonstrate extreme shear-thickening effects. We studythe aging of cornstarch particles in aqueous suspensions at room temperature by granulometry and rheologicalmeasurements. When starch is diluted in glycerol, no long-term changes are observed. The situation differswhen water is used as solvent. For volume fractions up to 20 vol %, when the cornstarch suspensions in waterare stored under continual agitation, we observe an increase in viscosity. When the cornstarch suspension isaged under quiescent conditions, no evolution of the particle size is observed. In the concentrated situation, therheological properties vary independent of the storage condition. We show that the increase in viscosity is relatedto air trapped in the pore space and to the swelling of the granules and leakage of the amylopectin componentof the starch into the surrounding water. The relative importance of the two processes depends upon the particleconcentration and upon the energy brought to the system.