Viscosity of Polymer Solutions and Molecular Weight Characterization
Viscosity of Polymer Solutions and Molecular Weight Characterization
复制标题
聚合物溶液的粘度和分子量表征
DOI：
10.1021/acsmacrolett.3c00219
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发表时间：
2023
影响因子：
7.015
通讯作者：
Colby, Ralph H.
中科院分区：
文献类型：
--
作者：
Dobrynin, Andrey V.;Sayko, Ryan;Colby, Ralph H.
自从Staudinger开创性地研究了稀溶液粘度及其与聚合物相对分子质量的关系以来，粘度分析已经成为表征聚合物的一种有价值的技术。传统的方法是基于浓度的二次函数c对溶液比粘度的Huggins近似。我们展示了如何通过将溶液比粘度ηsp表示为链重叠浓度c*的广义泛函ηsp(C)=α(c/c*)+(1-α)(c/c*)2来将该方法重新表述为通用形式，ηsp=1确定的数值系数α=0.745±0.005，对于θ溶剂，数值系数为0.625±0.008。这种粘度表示法可视为通过测量给定溶液浓度下的溶液粘度来确定分子量的校准曲线。此外，重叠浓度的分子量依赖关系提供了一种量化聚合物/溶剂亲和力和溶剂对链柔性影响的方法。将该方法扩展到半稀溶液，为在不需要稀释的情况下在广泛的浓度范围内获得分子量并从溶液粘度监测聚合反应过程中的变化开辟了一条途径。
Since the pioneering research by Staudinger on dilute solution viscosity and its relation to the polymer molecular weight, viscosity analysis has become a valuable technique for polymer characterization. The conventional approach is based on the Huggins approximation of the solution-specific viscosity by a quadratic function of concentration,c. We show how to reformulate this approach in a universal form by representing a solution-specific viscosity, ηsp, as a generalized universal function ηsp(c) = α(c/c*) + (1 – α)(c/c*)2of chain overlap concentration,c*, determined at ηsp= 1, with numerical coefficients α = 0.745 ± 0.005 for good and 0.625 ± 0.008 for a θ solvent. This viscosity representation can be viewed as a calibration curve for molecular weight determination from a measurement of the solution viscosity at a given solution concentration. Furthermore, the molecular weight dependence of the overlap concentration provides a means for quantifying the polymer/solvent affinity and the solvent effect on chain flexibility. The extension of the approach to semidilute solutions opens a path for obtaining molecular weight in a broad concentration range without requiring a dilution and monitoring its change during the polymerization reaction from solution viscosity.