The progressive onset of slip at the wall, which corresponds to a slip length increasing with the solicitation time before reaching a plateau, has been investigated for model viscoelastic polymer solutions, allowing one to vary the longest relaxation time while keeping constant solid–fluid interactions. A hydrodynamic model based on a Maxwell fluid and the classical Navier’s hypothesis of a linear response for the friction stress at the interface fully accounts for the data. In the limit of the linear viscoelasticity of the fluid, we could postulate a Newtonian response for the interfacial friction coefficient, reflecting the local character of solid–liquid friction mechanisms. Deviations between the experiments and our model are observed when the fluid is far from its linear viscoelastic behavior.
DOI: https://pubs-acs-org/doi/10.1021/acsmacrolett.0c00182
Arxiv: https://arxiv.org/abs/2002.03429