Shear thickening in model suspensions of sterically stabilized particles
Shear thickening in model suspensions of sterically stabilized particles
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DOI：
10.1122/1.550791
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发表时间：
1996-07-01
影响因子：
3.3
通讯作者：
Mewis, J
中科院分区：
文献类型：
--
作者：
Frith, WJ;dHaene, P;Mewis, J
在空间稳定的球形颗粒的亚微米模型悬浮液中，研究了剪切增稠(扩容)的开始。为此，使用了应力控制流变仪，因此可以在突然发生剪切增稠之后进行测量。给出了颗粒大小、颗粒浓度和悬浮介质性质对剪切稠化开始的影响的系统数据。作为第一近似值，临界剪切速率与介质粘度成反比。稳定剂聚合物介质的溶解能力的变化通过对空间位阻的厚度和硬度的影响引入了额外的变化。在较软的体系中，临界剪应力与稠密悬浮液中的颗粒浓度无关。对于更难的系统来说，情况似乎并非如此。颗粒半径a的影响可能有助于揭示剪切增稠的潜在机制。然而，这些数据不能让我们决定是用(2)标度临界剪切率，还是用(3)标度临界剪切率。后者似乎更适合较硬的系统，而前者则更适合较软的系统。(C)1996年流变学学会。
The onset of shear thickening (dilatancy) has been studied in submicron model suspensions of sterically stabilized spherical particles. Stress controlled rheometers have been used for this purpose, so that measurements can be performed beyond the onset of sudden shear thickening. Systematic data are presented for the effect of particle size, particle concentration, and the nature of the suspending medium on the onset of shear thickening. As a first approximation, the critical shear rate changes inversely proportional with the medium viscosity. The changing solvency of the medium for the stabilizer polymer introduces additional changes through effects on the thickness and stiffness of the steric barrier Thinner, stiffer barriers cause lower critical shear rates. In the softer systems the critical shear stress becomes independent of particle concentration in dense suspensions. This does not seem to be the case for the harder systems. The effect of particle radius a could shed some light on the underlying mechanisms of shear thickening. The data do not, however, enable us to decide between a scaling for the critical shear rate with a(2) or one with a(3). The latter seems more appropriate for harder systems, the former for softer ones. (C) 1996 Society of Rheology.