Slow Debye-type peak observed in the dielectric response of polyalcohols.
Slow Debye-type peak observed in the dielectric response of polyalcohols.
复制标题
在多元醇的介电响应中观察到缓慢的德拜型峰。
DOI：
10.1063/1.3294703
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
J. Swenson
中科院分区：
文献类型：
--
作者：
R. Bergman;H. Jansson;J. Swenson
玻璃形成液的介电弛豫谱通常表现出一种似乎令人惊讶的普遍的弛豫情景。然而，对于氢键液体，松弛动力学更为复杂。例如，一元醇的介电响应是由一个神秘的类似德拜的过程在更低的频率上主导的，而不是通常主导玻璃成形器光谱的结构阿尔法松弛。对于多元醇，这一过程一直被认为是不存在的，或者可能被低频下的电导和极化效应的强烈贡献所掩盖。我们在这里表明，类似德拜的过程，虽然不那么突出，但也存在于多元醇的反应中。它可以在磁化率的实部的导数中观察到，或者直接在虚部中观察到，如果通过在上电极上覆盖一层薄的特氟龙层来降低电导率的贡献。我们报道了几种多元醇介电谱的宽带研究结果：甘油、木糖醇和山梨醇。这些发现与玻璃成形器中超低(即比粘度相关的α松弛慢)动力学的其他实验观测结果有关。
Dielectric relaxation spectroscopy of glass forming liquids normally exhibits a relaxation scenario that seems to be surprisingly general. However, the relaxation dynamics is more complicated for hydrogen bonded liquids. For instance, the dielectric response of monoalcohols is dominated by a mysterious Debye-like process at lower frequencies than the structural alpha-relaxation that is normally dominating the spectra of glass formers. For polyalcohols this process has been thought to be absent or possibly obscured by a strong contribution from conductivity and polarization effects at low frequencies. We here show that the Debye-like process, although much less prominent, is also present in the response of polyalcohols. It can be observed in the derivative of the real part of the susceptibility or directly in the imaginary part if the conductivity contribution is reduced by covering the upper electrode with a thin Teflon layer. We report on results from broadband dielectric spectroscopy studies of several polyalcohols: glycerol, xylitol, and sorbitol. The findings are discussed in relation to other experimental observations of ultraslow (i.e., slower than the viscosity related alpha-relaxation) dynamics in glass formers.
影响因子：
4.4
作者：
Gainaru, C.;Lips, O.;Roessler, E. A.
通讯作者：
Roessler, E. A.