Molecular weight is a key parameter of any polymer. Characterizing the molecular weight of conjugated polymers is often nontrivial due to their semiflexible backbones and poor solubilities. Perhaps the most used technique for measuring the molecular weight is gel permeation chromatography (GPC), and results are often calibrated relative to flexible polymer standards. This mismatch between chain flexibilities of samples and standards, combined with poor sample solubility in the mobile phase, leads to inaccuracies in many GPC measurements of conjugated polymers. In this work, we use a universal calibration combined with in-line concentration measurements to yield reliably accurate results for polymers of various stiffnesses. Accuracy of results is verified with absolute molecular weights obtained from static light scattering. We show that measuring the refractive index increment is key to confirm full recovery of the polymer and ensure accurate values of the absolute molecular weight from GPC.

中文翻译：

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通过凝胶渗透色谱和静态光散射表征共轭聚合物的分子量

分子量是任何聚合物的关键参数。由于共轭聚合物的骨架半柔性和溶解性差，表征它们的分子量通常很重要。也许最常用的分子量测量技术是凝胶渗透色谱 (GPC)，其结果通常相对于灵活的聚合物标准进行校准。样品和标准品链灵活性之间的这种不匹配，再加上样品在流动相中的溶解度差，导致许多共轭聚合物 GPC 测量不准确。在这项工作中，我们使用通用校准与在线浓度测量相结合，为各种刚度的聚合物提供可靠准确的结果。结果的准确性通过静态光散射获得的绝对分子量进行验证。