title: Collective rearrangement at the onset of flow of a polycrystalline hexagonal columnar phase.
abstract: Creep experiments on polycrystalline surfactant hexagonal columnar phases show a power law regime, followed by a drastic fluidization before reaching a final stationary flow. The scaling of the fluidization time with the shear modulus of the sample and stress applied suggests that the onset of flow involves a bulk reorganization of the material. This is confirmed by x-ray scattering under stress coupled to in situ rheology experiments, which show a collective reorientation of all crystallites at the onset of flow. The analogy with the fracture of heterogeneous materials is discussed.
authors.affiliation: Laboratoire des Colloïdes, Verres et Nanomatériaux (UMR CNRS-UM2 5587), CC26, Université Montpellier 2, 34095 Montpellier Cedex 5, France.
authors.forename: Teresa
authors.initials: T
authors.lastname: Bauer
authors.forename: Julian
authors.initials: J
authors.lastname: Oberdisse
authors.forename: Laurence
authors.initials: L
authors.lastname: Ramos