title: Contrasting friction and diffusion in molecularly thin confined films.
abstract: We study, using fluorescence correlation spectroscopy, translational diffusion in molecularly thin liquids confined within a surface forces apparatus. The diffusion coefficient decreases exponentially from the edges towards the center of the Hertzian contact and further suggests the presence of a small number of distinct diffusion processes. This holds alike a crystallizable fluid (OMCTS) and a glass-former (1,2-propane diol), both of which displayed static friction. We conclude that friction, the average of an ensemble of molecules, masked massively heterogeneous molecular mobility.
authors.affiliation: Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Ashis
authors.initials: A
authors.lastname: Mukhopadhyay
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhao
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Bae
authors.forename: Steve
authors.initials: S
authors.lastname: Granick