Properties Measured by Friction Force Microscopy
Jon A. Hammerschmidt, Bahram
Moasser, and Wayne L. Gladfelter
Department of Chemistry
University of Minnesota, Minneapolis
Center for Interfacial Engineering,
187 Shepherd Laboratories
University of Minnesota, Minneapolis,
Richard R. Jones
Medical Products Division, E.
I. du Pont de Nemours and Co.
Staton Road, Brevard, North
A correlation has been made between
bulk viscoelastic relaxations and surface friction measured by friction
force microscopy (FFM). Using friction as a measure of dissipated energy
in conjunction with a measured tip/surface contact diameter has allowed
the determination of a characteristic relaxation rate. The velocity dependence
of friction measured on polyvinyl alcohol (PVOH), polyvinyl acetate (PVAc),
polyethylene terephthalate (PET), and gelatin films is consistent with
relaxations as measured by traditional mechanical and dielectric methods.
This discovery enables viscoelastic characterization of polymer surfaces
and has the potential to probe energy dissipation on the nanometer scale.