Polymer Viscoelastic Properties Measured by Friction Force Microscopy
Jon A. Hammerschmidt, Bahram Moasser, and Wayne L. Gladfelter
Department of Chemistry
University of Minnesota, Minneapolis Minnesota 55455
Greg Haugstad
Center for Interfacial Engineering, 187 Shepherd Laboratories
University of Minnesota, Minneapolis, Minnesota 55455
Richard R. Jones
Medical Products Division, E. I. du Pont de Nemours and Co.
Staton Road, Brevard, North Carolina 28712
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 the a and/or b 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.