Melting and freezing lines for a mixture of charged colloidal spheres with spindle-type phase diagram.
Melting and freezing lines for a mixture of charged colloidal spheres with spindle-type phase diagram.
复制标题
带纺锤型相图的带电胶体球混合物的熔化线和冷冻线。
DOI：
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发表时间：
2010
影响因子：
4.4
通讯作者：
T. Palberg
中科院分区：
文献类型：
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作者：
Nina Lorenz;T. Palberg
我们测量了尺寸比 Л=0.9 和电荷比 Λ=0.96 的同电荷胶体球二元混合物的相行为，作为粒子数密度 n 和组成 p 的函数。在彻底去离子的条件下，水悬浮液形成所有组合物的体心立方结构的固溶体。作为成分函数的凝固线和熔化线表现出相反的行为，并打开一个宽阔的纺锤形共存区域。由于缺乏更复杂的处理，我们将混合物中的相互作用建模为有效的单组分对能量，考虑了数量加权的有效电荷和筛选常数。利用这一描述，我们发现在实验误差范围内，实验熔点的位置符合用几种理论方法制造的单分散、单组分汤川系统预测的熔点范围。我们进一步讨论，对精确相图形状的详细理解，包括共存区域的成分依赖性宽度，将需要扩展的理论处理。
We have measured the phase behavior of a binary mixture of like-charged colloidal spheres with a size ratio of Γ=0.9 and a charge ratio of Λ=0.96 as a function of particle number density n and composition p. Under exhaustively deionized conditions, the aqueous suspension forms solid solutions of body centered cubic structure for all compositions. The freezing and melting lines as a function of composition show opposite behavior and open a wide, spindle shaped coexistence region. Lacking more sophisticated treatments, we model the interaction in our mixtures as an effective one-component pair energy accounting for number weighted effective charge and screening constant. Using this description, we find that within experimental error the location of the experimental melting points meets the range of melting points predicted for monodisperse, one-component Yukawa systems made in several theoretical approaches. We further discuss that a detailed understanding of the exact phase diagram shape including the composition dependent width of the coexistence region will need an extended theoretical treatment.