On the polymer entropic force singularity and its relation to extensional stress relaxation and filament recoil
On the polymer entropic force singularity and its relation to extensional stress relaxation and filament recoil
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DOI：
10.1122/1.1626679
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发表时间：
2004-01-01
影响因子：
3.3
通讯作者：
Sridhar, T
中科院分区：
文献类型：
--
作者：
Shaqfeh, ESG;McKinley, GH;Sridhar, T
我们研究使用瞬态拉伸流变学作为一种手段，检查蠕虫状和自由连接的链行为的聚合物在稀溶液中在高延伸。我们从理论上证明，这两种链类型遵循不同的幂律应力衰减函数的短时间后，停止强拉伸流。不同的幂律对于不同的应变和应变率历史是通用的，而且，是熵弹簧力定律中接近完全扩展时的奇异性的签名。我们还表明，这些幂律指数是直接相关的无惯性的弹性反冲的聚合物溶液的拉伸长丝。最后，这些理论预测进行了比较，实验结果的应力松弛后，单分散聚苯乙烯溶液的扩展。当建模为自由连接的链，我们发现很好的协议与理论预测。(C)2004流变学学会。
We examine the use of transient extensional rheology as a means of examining worm-like and freely jointed chain behavior of polymers in dilute solution at high extension. We demonstrate theoretically that both chain types follow different power-law stress decay functions for short times after cessation of strong extensional flow. The different power laws are universal for different strain and strain-rate histories and, moreover, are signatures of the singularities in the entropic-spring force laws that develop close to full extension. We also demonstrate that these power-law exponents are directly related to the inertialess elastic recoil of an extensionally stretched filament of polymer solution. Finally, these theoretical predictions are compared to experimental results for the relaxation of stress following extension for monodisperse polystyrene solutions. When modeled as freely jointed chains, we find excellent agreement with the theoretical predictions. (C) 2004 The Society of Rheology.