Concentration fluctuation in alcohol-water mixture : Is the structural aspect of poly-disperse mass-fractal universal?

醇水混合物的中尺度结构以浓度波动或微观非均质性为特征。然而，浓度波动的结构细节和波动的分子起源仍然不清楚。需要对酒精混合物的中尺度结构进行更详细的结构研究。我们以前报道过，利用一种新开发的小角中子散射强度可视化分析方法，用多分散质量分形表征了1-丙醇-水混合物的中尺度结构。本研究的目的是检验这种多分散质量分形的结构方面是否在其他酒精-水混合物中普遍观察到。为此，我们对叔丁醇-水进行了小角中子散射测量。用分形理论分析了混合料的浓度波动。利用更大规模的反向蒙特卡罗技术，对浓度波动的结构进行了可视化。可视化结构的渗透分析表明，1-丙烷-水混合物的浓度波动具有多分散的质量分形特征。这些发现有力地表明，多分散的质量分形是各种醇水混合物的共同结构特征。我们还将可视化技术应用于液态Rb-Se和Bi-Br混合物，以了解这些液体的近程和中程结构。结果表明，在Rb-Se混合物的可视化模型结构中存在许多空洞。利用Delaunay简化法对孔洞进行分析，发现由于孔洞和结构中的硒链在化学上有序排列，所观察到的前峰对应于浓度-浓度结构因子的前峰。我们强调，中尺度结构的可视化对于理解各种液体混合物的复杂性至关重要。少

The mesoscale structure of alcohol-water mixtures is characterized by concentration fluctuation or micro-heterogeneity. However the structural details of the concentration fluctuation and the molecular origin of the fluctuation are still obscure. More detailed structural studies on the mesoscale structure of the alcohol mixtures are needed. We reported previously that the mesoscale structure of the 1-propanol-water mixtures was characterized by poly-disperse mass-fractals by means of a newly developed visualization-analysis of small angle neutron scattering intensity. The purpose of this study is to examine whether this structural aspect of the poly-disperse mass-fractals is commonly observed in other alcohol-water mixtures. For this purpose we have carried out small angle neutron scattering measurement on tert-butyl alcohol-water. Concentration fluctuation of the mixture has been analyzed in terms of fractal. Structure of the concentration fluctuation has been visualized by means of a … More large-scale reverse Monte Carlo technique. Percolation analysis of the visualized structure shows that the concentration fluctuation is characterized by poly-disperse mass fractals, which has been found for 1-propano-water mixture. These findings strongly suggest that the poly-disperse mass-fractal is a common structural characteristic in various alcohol-water mixtures.We have also applied the visualization technique to liquid Rb-Se and Bi-Br mixtures in order to understand the short-range and intermediate-range structures of these liquids. It was found that there were many voids in the visualized model structure of Rb-Se mixtures. From the void analysis using Delaunay simplices it has been revealed that the observed pre-peak corresponds to a pre-peak in the concentration-concentration structure factor due to the chemically ordered packing of the voids and Se chains in the structure.We emphasize that the visualization of the mesoscale structure is essentially important to understand the complexity in various liquid mixtures. Less