Shear-banding in polyacrylamide solutions revealed via optical coherence tomography velocimetry
Shear-banding in polyacrylamide solutions revealed via optical coherence tomography velocimetry
复制标题
DOI：
10.1039/c2sm26395e
复制
发表时间：
2012-11
期刊：
影响因子：
3.4
通讯作者：
Shaden Jaradat;M. Harvey;T. Waigh
中科院分区：
文献类型：
--
作者：
Shaden Jaradat;M. Harvey;T. Waigh
我们在流体流变仪中使用光学相干断层扫描测速仪来研究含有不同聚合物分子量和浓度的聚丙烯酰胺（PAM）溶液的流变性，具有皮升探测体积。从低分子量样品中获得的线速度分布，剪切下的牛顿流体的特性，成为剪切带时，较长的聚合物链（分子量5 000 000及以上）在足够高的浓度使用。在进一步增加浓度时，剪切带变得不那么占主导地位，并且在流变仪的两个板上发生显著的壁滑移。我们描述的剪切带和壁滑现象在我们的样品中的速度分布计算的参数，并使用我们的数据来建议一个动态相图表示的线性，剪切带，和壁滑制度作为PAM分子量和浓度的函数。
We used optical coherence tomography velocimetry inside a fluids rheometer to study the rheology of a family of polyacrylamide (PAM) solutions that contain different polymer molecular weights and concentrations, with picolitre probing volumes. The linear velocity profiles obtained from low molecular weight samples, characteristic of Newtonian fluids under shear, become shear-banded when longer polymer chains (molecular weights 5 000 000 and above) are used at sufficiently high concentrations. Upon increasing the concentration further, shear-banding becomes less dominant and significant wall-slip takes place on the two plates of the rheometer. We describe the shear-banding and wall-slip phenomena in our samples in terms of parameters calculated from the velocity profiles, and use our data to suggest a dynamic phase diagram indicating the linear, shear-banding, and wall-slip regimes as functions of PAM molecular weight and concentration.