Carbopol: From a simple to a thixotropic yield stress fluid
Carbopol: From a simple to a thixotropic yield stress fluid
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卡波姆：从简单的屈服应力流体到触变屈服应力流体
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
D. Bonn
中科院分区：
文献类型：
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作者：
M. Dinkgreve;Mina Fazilati;M. Denn;D. Bonn
文献中正在讨论广泛使用的模型屈服应力流体Carbopol的流动行为。一些论文表明，它确实是许多人认为的简单模型屈服应力流体。然而，其他作者报告流变滞后的流动曲线，瞬态剪切带，持续了很长一段时间，打破了前后对称的落球实验。这种行为在过去与触变屈服应力流体，这是非常不同的简单的。我们目前的实验表明，这两种类型的行为可能会发现在同一类型的卡波姆，这取决于准备：经过长时间的强烈搅拌，系统变得轻微触变。使用荧光标记的Carbopol进行的流动可视化实验阐明了系统的简单行为和触变行为之间的差异：搅拌将聚合物破碎成较小的碎片，其中一些碎片非常小，以至于...
There is an ongoing discussion in the literature about the flow behavior of the widely used model yield-stress fluid Carbopol. Some papers show that it is indeed the simple model yield-stress fluid that many people believe it to be. However, other authors report rheological hysteresis in the flow curve, transient shear banding that persists for a very long time, and the breaking of fore-aft symmetry in a falling ball experiment. Such behaviors have in the past been associated with thixotropic yield stress fluids, which are very different from simple ones. We present experiments that suggest that both types of behavior may be found in the same type of Carbopol, depending on the preparation: After strong stirring for a long time, the system becomes slightly thixotropic. Flow visualization experiments with fluorescently labeled Carbopol elucidate the difference between the simple and thixotropic behavior of the systems: The stirring breaks the polymers into smaller fragments, some of which are so small that ...