Chain dynamics in entangled polymers: Diffusion versus rheology and their comparison
Chain dynamics in entangled polymers: Diffusion versus rheology and their comparison
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缠结聚合物中的链动力学：扩散与流变及其比较
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
Shi‐Qing Wang
中科院分区：
文献类型：
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作者：
Shi‐Qing Wang
这篇综述文章仔细检查并重新分析了关于示踪剂和自链扩散系数Dtr和Ds沿着相应的零剪切粘度η0的广泛可用的文献数据，以表明Ds <$M−ν从ν > 2.0开始，并随着分子量M增加超过M/Me = 10-20而收敛到Dtr <$M−2.0所表现出的渐近标度，与η0的渐近标度M3的开始相比，通常发生在M/Me = 10-20时。对这些观察结果的连贯分析表明，观察到的Ds交叉是由于约束释放效应，其在M/Me = 10-20附近减小，并且当基质分子量P远大于M时，在Dtr的测量中可以忽略不计。轮廓长度波动（CLF）效应被认为是导致η0的分子量标度显著偏离其极限行为M3的原因，但对链扩散的直接影响很小。CLF效应对Ds的不存在导致乘积η 0 Ds对M的线性依赖性强得多，这在之前已经观察到。© 2003威利期刊公司聚合物科学杂志B部分：聚合物物理41：1589-1604，2003
This review article scrutinizes and reanalyzes the extensively available literature data on the tracer and self chain diffusion coefficients Dtr and Ds along with the corresponding zero-shear viscosity η0 to show that Ds ∝ M−ν starts with ν > 2.0 and converges to the asymptotic scaling exhibited by Dtr ∝ M−2.0 as the molecular weight M increases beyond M/Me = 10–20, in contrast to the onset of the asymptotic scaling M3 for η0 taking place typically for M/Me ≫ 10–20. A coherent analysis of these observations leads to the suggestion that the observed crossover in Ds is due to the constraint release effect, which diminishes around M/Me = 10–20 and is negligible in measurements of Dtr when the matrix molecular weight P is much greater than M. The contour length fluctuation (CLF) effect, which is believed to cause the molecular weight scaling of η0 to deviate significantly from its limiting behavior of M3, has little direct influence on the chain diffusion. The absence of the CLF effect on Ds leads to a much stronger than linear dependence of the product η0Ds on M, which has been observed previously. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1589–1604, 2003