Fakultät für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
J Chem Phys. 2012 Aug 14;137(6):064508. doi: 10.1063/1.4740236.
Propylene carbonate and a mixture of two secondary amides, N-methylformamide and N-ethylacetamide, are investigated by means of broadband dielectric and mechanical shear spectroscopy. The similarities between the rheological and the dielectric responses of these liquids and of the previously investigated tripropylene glycol are discussed within a simple approach that employs an electrical circuit for describing the frequency-dependent behavior of viscous materials. The circuit is equivalent to the Gemant-DiMarzio-Bishop model, but allows for a negative capacitive element. The circuit can be used to calculate the dielectric from the mechanical response and vice versa. Using a single parameter for a given system, good agreement between model calculations and experimental data is achieved for the entire relaxation spectra, including secondary relaxations and the Debye-like dielectric peak in the secondary amides. In addition, the predictions of the shoving model are confirmed for the investigated liquids.
采用宽带介电和机械剪切光谱法研究了碳酸丙烯酯和两种仲酰胺的混合物，N-甲基甲酰胺和 N-乙基乙酰胺。在一种简单的方法内讨论了这些液体以及先前研究过的三丙二醇的流变和介电响应之间的相似性，该方法使用电路来描述粘性材料的频率相关行为。该电路等效于 Gemant-DiMarzio-Bishop 模型，但允许存在负电容元件。该电路可用于根据机械响应计算介电常数，反之亦然。对于给定系统使用单个参数，在整个弛豫谱中，包括仲松弛和次级酰胺中的类德拜介电峰，模型计算和实验数据之间均达成了良好的一致。此外，还证实了所研究液体的推斥模型的预测。
