Sedimentation stacking diagrams of binary mixtures of thick and thin hard rods
Sedimentation stacking diagrams of binary mixtures of thick and thin hard rods
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DOI：
10.1039/c6sm00736h
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发表时间：
2016-01-01
期刊：
影响因子：
3.4
通讯作者：
van Roij, Rene
中科院分区：
文献类型：
--
作者：
Drwenski, Tara;Hooijer, Patrick;van Roij, Rene
我们使用 Onsager 理论和局部密度近似来研究粗硬棒和细硬棒二元混合物的沉降扩散平衡密度分布。我们构建了三种直径比的堆积图，发现即使是仅具有各向同性向列相分层的简单纺锤形相图也可能导致反直觉的堆积序列，例如夹在两个向列相之间的各向同性相。对于这里考虑的最复杂的相图，我们发现了十六种不同的堆积序列，其中包括几个具有五个沉积层的序列。通过在成分-压力和密度-密度相图中添加沉降路径并计算密度和成分分布，我们表明应谨慎得出基于沉降-扩散平衡的二元混合物本体相图的结论。
We use Onsager theory and the local density approximation to study sedimentation-diffusion equilibrium density profiles of binary mixtures of thick and thin hard rods. We construct stacking diagrams for three diameter ratios, and find that even a simple spindle-shaped phase diagram with only isotropic-nematic demixing can lead to counter-intuitive stacking sequences such as an isotropic phase sandwiched between two nematic phases. For the most complex phase diagram considered here, we find sixteen distinct stacking sequences, including several with five sedimented layers. By adding sedimentation paths to composition-pressure and density-density phase diagrams and calculating density and composition profiles, we show that conclusions about bulk phase diagrams of binary mixtures on the basis of sedimentation-diffusion equilibria should be drawn warily.