• DOI:10.1103/physrevmaterials.6.l042601
• Corpus ID: 245827976

Residual stresses and shear-induced overaging in boehmite gels

@article{Sudreau2022ResidualSA,
  title={Residual stresses and shear-induced overaging in boehmite gels},
  author={Iana Sudreau and Mathilde Auxois and Marion Servel and {\'E}ric L{\'e}colier and S{\'e}bastien Manneville and Thibaut Divoux},
  journal={Physical Review Materials},
  year={2022}
}

• Iana Sudreau, Mathilde Auxois, +3 authors T. Divoux
• Published 7 January 2022
• Materials Science
• Physical Review Materials

Colloidal gels respond as soft solids at rest, whereas they flow as liquids under external shear. Starting from a fluidized state under an applied shear rate ˙ γ p , abrupt flow cessation triggers a liquid-to-solid transition during which the stress relaxes towards a so-called residual stress σ res that tallies a macroscopic signature of previous shear history. Here, we report on the liquid-to-solid transition in gels of boehmite, an aluminum oxide, that shows a remarkable nonmonotonic stress relaxation towards a residual stress σ res ( ˙ γ p ) characterized by a dual behavior relative to a critical value ˙ γ c of the shear rate ˙ γ p . Following shear at ˙ γ p > ˙ γ c , the gel obtained upon flow cessation is insensitive to shear history, and the residual stress is negligible. However, for ˙ γ p < ˙ γ c , the gel encodes some memory of the shear history, and σ res increases for decreasing shear rate, directly contributing to reinforcing the gel viscoelastic properties. Moreover, we show that both σ res and the gel viscoelastic properties increase logarithmically with the strain accumulated during the shear period preceding flow cessation. Such a shear-induced “overaging” phenomenon bears great potential for tuning the rheological properties of colloidal gels. DOI: