Observations of wall slip and shear banding in an entangled DNA solution
Observations of wall slip and shear banding in an entangled DNA solution
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DOI：
10.1021/ma702332n
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发表时间：
2008-04-08
期刊：
影响因子：
5.5
通讯作者：
Wang, Shi-Qing
中科院分区：
文献类型：
--
作者：
Boukany, Pouyan E.;Hu, Y. Thomas;Wang, Shi-Qing
我们有。在Couette和锥板两种几何构型下，用粒子跟踪测速仪研究了缠绕DNA溶液的非线性流动行为。在视剪切速率伽马(APP)和S(-1)为0.1时，速度剖面在缝隙内呈线性分布。在a，p&t；40 S(-1)的终点区以外，速度剖面在应力最大值后暂时变成条带，并在很长一段时间内显示出巨大的壁面滑移，整体上几乎没有剪切条带。在伽马(APP)>；40 S(-1)处，速度剖面逐渐弯曲，并在几百个应变单位后形成具有尖锐界面的条带。在稳定状态下，高剪切带厚度随表观剪切速率的增加而线性增加。当伽马(APP)=1000时，S(-1)，速度分布恢复到线性。
We have. studied nonlinear flow behavior of entangled DNA solutions using particle tracking velocimetry in Couette and cone/plate geometries. At apparent shear rate gamma(app) < 0.1 s(-1), the velocity profile is linear across the gap. Beyond the terminal region with a,p < 40 s(-1), the velocity profile becomes temporarily banded after the stress maximum and shows massive wall slip at long times with little shear banding in the bulk. At gamma(app) > 40 s(-1), the velocity profile progressively curves and becomes banded with a sharp interface after hundreds of strain units. In the steady state, the thickness of high-shear band increases linearly with the apparent shear rate. At gamma(app) = 1000 s(-1), the velocity profile returns to linearity.