Eur. Phys. J. E 8, 129-136 (2002)
DOI: 10.1140/epje/i2000-10102-5
Using adhesion to probe viscoelasticity of polymer film surfaces: A quartz crystal microbalance study
J.A. Forrest1, J. Mattsson2 and L. Börjesson21 Department of Physics and Guelph-Waterloo Physics Institute, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
2 Department of Experimental Physics, Chalmers University of Technology, SE-412 96, Göteborg, Sweden
jforrest@uwaterloo.ca
(Received 28 August 2000 and Received in final form 17 September 2001)
Abstract
We have used a quartz crystal microbalance to monitor the adhesion of small particles
to the surface of polystyrene films. This technique is shown to provide
a signature of viscoelastic relaxation processes at the polymer surface. For
values less than
104 and greater than
105, this signature occurs at
a temperature
K above the measured bulk glass transition temperature,
. For intermediate values of
however, the relaxation signature occurs at temperatures
as low as 7 K above the bulk
. This observation suggests a slight decrease in the
value near the polymer surface. A model incorporating the effects of enrichment
of polymer chain ends at the free surface was considered and found to provide
a quantitative description of the data.
64.70.Pf - Glass transitions.
68.35.Np - Adhesion.
68.35.Gy - Mechanical properties; surface strains.
82.35.Lr - Physical properties of polymers.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002
