title: Slip and flow of hard-sphere colloidal glasses.
abstract: We study the flow of concentrated hard-sphere colloidal suspensions along smooth, nonstick walls using cone-plate rheometry and simultaneous confocal microscopy. In the glass regime, the global flow shows a transition from Herschel-Bulkley behavior at large shear rate to a characteristic Bingham slip response at small rates, absent for ergodic colloidal fluids. Imaging reveals both the "solid" microstructure during full slip and the local nature of the "slip to shear" transition. Both the local and global flow are described by a phenomenological model, and the associated Bingham slip parameters exhibit characteristic scaling with size and concentration of the hard spheres.
authors.affiliation: Scottish Universities Physics Alliance (SUPA) and School of Physics, The University of Edinburgh, Kings Buildings, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom.
authors.forename: P
authors.initials: P
authors.lastname: Ballesta
authors.forename: R
authors.initials: R
authors.lastname: Besseling
authors.forename: L
authors.initials: L
authors.lastname: Isa
authors.forename: G
authors.initials: G
authors.lastname: Petekidis
authors.forename: W C K
authors.initials: WC
authors.lastname: Poon