Rheological properties of aging thermosensitive suspensions

Purnomo, Eko H. and Ende van den, Dirk and Mellema, Jorrit and Mugele, Frieder (2007) Rheological properties of aging thermosensitive suspensions. Physical Review E: Statistical, nonlinear, and soft matter physics, 76 (2). 021404. ISSN 1539-3755

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Abstract:	Aging observed in soft glassy materials inherently affects the rheological properties of these systems and has been described by the soft glassy rheology (SGR) model [S. M. Fielding et al., J. Rheol. 44, 323 (2000)]. In this paper, we report the measured linear rheological behavior of thermosensitive microgel suspensions and compare it quantitatively with the predictions of the SGR model. The dynamic moduli [G[prime](omega,t) and G[double-prime](omega,t)] obtained from oscillatory measurements are in good agreement with the model. The model also predicts quantitatively the creep compliance J(t−tw,tw), obtained from step stress experiments, for the short time regime [(t−tw)<tw]. The relative effective temperature [script X]/[script X]g obtained from both the oscillatory and the step stress experiments is indeed less than 1 ([script X]/[script X]g<1) in agreement with the definition of aging. Moreover, the elasticity of the compressed particles (Gp) increases with increased compression, i.e., the degree of hindrance and consequently also the bulk elasticity (G[prime] and 1/J) increases with the degree of compression.
Item Type:	Article
Copyright:	© 2007 American Physical Society
Faculty:	Science and Technology (TNW)
Research Group:	Physics of Complex Fluids (PCF)
Link to this item:	http://purl.utwente.nl/publications/59162
Official URL:	http://dx.doi.org/10.1103/PhysRevE.76.021404
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