Transformation relationships among monomers, micelles, metastable solid, and stable solid in aqueous cetylpyridinium chloride solution.
Transformation relationships among monomers, micelles, metastable solid, and stable solid in aqueous cetylpyridinium chloride solution.
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DOI：
10.1021/jp103293x
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发表时间：
2010-08
期刊：
影响因子：
--
通讯作者：
S. Sasaki
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文献类型：
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作者：
S. Sasaki
研究了十六烷基氯化吡啶（CPC）在水溶液中的Krafft转变过程中单体、胶束、亚稳固体和稳定固体之间的相变动力学。Krafft转变伴随着电导率的降低和介电常数Δ ε的大幅度增加，Δ ε在转变完成后消失。观察到的大δ相转变为亚稳相的时间比观察到的大δ相转变为稳定相的时间短得多。从观察时间的Δ ε，形成之间的亚稳态和稳定的固体的边界被确定为温度和CPC浓度的函数。从界面上可以看出，胶束溶液中形成了亚稳固体。介稳固体悬浮液的电导率kappa在介稳-稳定转变过程中的变化表明，在溶液中，介稳固体向稳定固体的固溶限制变态。从kappa变化的时间过程中获得的亚稳-稳定的转变持续时间的Arrhenius图给出了290 kJ/mol的亚稳固溶限制的亚稳-稳定的转变的高活化能。
Kinetic studies on metamorphoses among monomer, micelle, metastable solid, and stable solid during the Krafft transition of cetylpyridinium chloride (CPC) in the aqueous solution were carried out. The Krafft transition accompanied a decrease of the electric conductance with a large increment of the dielectric permittivity Delta epsilon, which vanished after finishing the transition. The observing duration of large Delta epsilon in transforming to the metastable solid was much shorter than the duration in transforming to the stable solid. From the observing duration of Delta epsilon, a formation boundary between the metastable and the stable solids was determined as a function of the temperature and the CPC concentration. It was found from the boundary that the metastable solid forms in the micelle solution. A change in the electric conductivity kappa of metastable solid suspensions during metastable-stable transformation suggests the solid dissolution-limited metamorphosis of metastable solid into the stable solid in the solution. Arrhenius plots of the metastable-stable transformation durations obtained from the time courses of kappa changes gave the high activation energy of 290 kJ/mol for the metastable solid dissolution-limited metastable-stable transition.