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Article
Nature of Steady Flow in Entangled Fluids Revealed by Superimposed Small Amplitude Oscillatory Shear
Journal of Rheology
  • Pouyan E. Boukany, University of Akron Main Campus
  • Shi-Qing Wang, University of Akron Main Campus
Document Type
Article
Publication Date
12-1-2009
Disciplines
Abstract
We carry out a systematic investigation into steady-state shear behavior of six entangled solutions based on a superposition of continuous shear and small amplitude oscillatory shear (SAOS). During steady shear in the shear thinning regime, the superimposed SAOS frequency sweep measurements reveal characteristics of viscous liquids, e. g., terminal dynamics, on the experimental time scale of the reciprocal shear rate. The residual entanglement network retains the same level of elastic stiffness as the equilibrium system does. Consistent with the convective constraint release idea, chains in the network are forced to pass around each other as they must do so to undergo steady flow. When such a sample is examined at significantly short time scales, chains are unable to pass around and the signature of this residual entanglement is that the storage modulus is greater than the loss modulus at higher frequencies than the applied shear rate. The particle-tracking velocimetric observations confirm that whether shear banding is present or not does not affect the basic "terminal flow" character revealed by the superimposed SAOS. (C) 2009 The Society of Rheology. [DOI: 10.1122/1.3236523]
Citation Information
Pouyan E. Boukany and Shi-Qing Wang. "Nature of Steady Flow in Entangled Fluids Revealed by Superimposed Small Amplitude Oscillatory Shear" Journal of Rheology Vol. 53 Iss. 6 (2009) p. 1425 - 1435
Available at: http://works.bepress.com/shi-qing_wang/8/