title: Using adhesion to probe viscoelasticity of polymer film surfaces: a quartz crystal microbalance study.
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 M(n) values less than 10(4) and greater than 10(5), this signature occurs at a temperature approximately 12.5 K above the measured bulk glass transition temperature, T(g). For intermediate values of M(n) however, the relaxation signature occurs at temperatures as low as 7 K above the bulk T(g). This observation suggests a slight decrease in the T(g) 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.
authors.affiliation: Department of Physics and Guelph-Waterloo Physics Institute, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1. jforrest@uwaterloo.ca
authors.forename: J A
authors.initials: JA
authors.lastname: Forrest
authors.forename: J
authors.initials: J
authors.lastname: Mattsson
authors.forename: L
authors.initials: L
authors.lastname: Börjesson