Orthogonal superposition rheometry of colloidal gels: time-shear rate superposition†,Soft Matter

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Orthogonal superposition rheometry of colloidal gels: time-shear rate superposition†
Soft Matter ( IF 2.9 ) Pub Date : 2018-10-10 00:00:00 , DOI: 10.1039/c8sm01512k
Sang Hoon Sung _{1,

2,

3,

4} , Sunhyung Kim _{5,

6,

7,

8} , Jan Hendricks _{9,

10,

11,

12} , Christian Clasen _{9,

10,

11,

12} , Kyung Hyun Ahn _{1,

2,

3,

4}

Affiliation

We explore the relaxation behavior of model colloidal gels under steady shear flow by means of orthogonal superposition rheometry. Fumed silica and carbon black dispersions in Newtonian matrices are used as a model system. As shear rate increases, the frequency dependent orthogonal moduli of the gels shift along the frequency axis without changing their shape, which finally can be superimposed to yield a single master curve. This indicates that the shear rate tunes a master clock for overall relaxation modes in the sheared colloidal gels to produce a “time-shear rate superposition (TSS)”, as temperature does in polymeric liquids to produce a time-temperature superposition (TTS). The horizontal shift factor required at each shear rate to obtain the master curve is found to be directly proportional to the suspension viscosity for all the cases. From this result, we suggest that the suspension viscosity determines the overall relaxation time of the particles in the flowing colloidal gel.

中文翻译：

胶体凝胶的正交叠加流变学：时间剪切速率叠加†

我们通过正交叠加流变仪研究了在稳定剪切流作用下模型胶体凝胶的弛豫行为。牛顿基体中的气相二氧化硅和炭黑分散体用作模型系统。随着剪切速率的增加，凝胶的频率相关正交模量沿频率轴移动而不改变其形状，最终可以叠加以生成单个主曲线。这表明剪切速率调整了剪切胶体凝胶中总体弛豫模式的主时钟，以产生“时间-剪切率叠加（TSS）”，就像聚合物液体中的温度产生时间-温度叠加（TTS）一样。在所有情况下，发现每种剪切速率下获得主曲线所需的水平位移因子都与悬浮液粘度成正比。

更新日期：2018-10-10

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