Adhesion and Friction Mechanisms of Polymer-on-Polymer Surfaces
Nobuo Maeda,
Nianhuan Chen,
Matthew Tirrell,
Jacob N. Israelachvili*
The adhesion and friction of smooth polymer surfaces were studied
below the glass transition temperature by use of a surface forces
apparatus. The friction force of a crosslinked polymer was orders of
magnitude less than that of an uncrosslinked polymer. In contrast,
after chain scission of the outermost layers, the adhesion hysteresis
and friction forces increase substantially. These results show that
polymer-polymer adhesion hysteresis and friction depend on the dynamic
rearrangement of the outermost polymer segments at shearing interfaces,
and that both increase as a transition is made from crosslinked
surfaces to surfaces with long chains to surfaces with quasi-free ends.
The results suggest new ways for manipulating the adhesion and friction
of polymer surfaces by adjusting the state of the surface chains.
Department of Chemical Engineering, Materials Department, and
Materials Research Laboratory, College of Engineering, University of
California, Santa Barbara, CA 93106, USA.
*
To whom correspondence should be addressed. E-mail:
jacob{at}engineering.ucsb.edu
