Volume 79, Number 1, July 2007
Article Number 18001
Number of page(s) 5
Section Interdisciplinary Physics and Related Areas of Science and Technology
Published online 04 June 2007
EPL, 79 (2007) 18001
DOI: 10.1209/0295-5075/79/18001

Heterogeneity of structural relaxation in a particle-suspension system

Xiaorong Wang and Christopher G. Robertson

Applied Physics Research Group, Bridgestone Americas, Center for Research & Technology 1200 Firestone Parkway, Akron, OH 44317-0001, USA

received 22 February 2007; accepted in final form 15 May 2007; published July 2007
published online 4 June 2007

We found the mechanism of how a silica-particle$\hbox{--} $reinforced elastomer after being sheared in oscillation at a strain could produce a spectrum hole or a drop in its dissipation spectrum at that amplitude, but not at other amplitudes. We also found that sequential holding the system at two strains could produce one or two holes depending on the deformation histories. When the second holding strain was higher than the first, the effect of hole burning of only high strain was evident, whereas the effects of hole burning at both strains were revealed when the second strain was lower than the first. This unexpected discovery suggests that the structural relaxations of a particle-suspension system are heterogeneous, and shearing at a fixed strain only affects part of its relaxation spectra.

83.80.Hj - Suspensions, dispersions, pastes, slurries, colloids.
83.85.Vb - Small amplitude oscillatory shear (dynamic mechanical analysis).
81.05.Qk - Reinforced polymers and polymer-based composites.

© Europhysics Letters Association 2007