title: How confined lubricants diffuse during shear.
abstract: The translational diffusion of a fluorescent dye embedded at a dilute concentration in a confined fluid was compared at rest and during shear. The fluid, octamethylcyclotetrasiloxane (OMCTS), was confined between step-free muscovite mica to thickness 3-4 layers. Fluorescence correlation spectroscopy showed that the time scales of intensity-intensity autocorrelation functions were essentially the same during shear and at rest, except they were faster during shear by a factor of 2 to 5. This dynamical probe of how liquids order in molecularly thin films fails to support the hypothesis that shear produced a melting transition.
authors.affiliation: Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA.
authors.forename: Ashis
authors.initials: A
authors.lastname: Mukhopadhyay
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Bae
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhao
authors.forename: Steve
authors.initials: S
authors.lastname: Granick