Contrasting friction and diffusion in molecularly thin confined films.
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.
Mukhopadhyay
Ashis
A
Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, USA.
Zhao
Jiang
J
Bae
Sung Chul
SC
Granick
Steve
S