标题： 二元混合物中抗磁性胶体薄片在外部磁场中的相行为 显示英文标题

标题： Phase behaviour of binary mixtures of diamagnetic colloidal platelets in an external magnetic field

摘要： 使用基本量密度泛函理论，我们研究了具有零厚度的圆形板状粒子二元混合物中的 paranematic-向列相和向列相-向列相的相共存。外部磁场引起单轴对齐，并以与板状粒子面积成比例的强度作用于板状粒子。在粒子直径比lambda=1.5时，系统表现出paranematic-向列相共存。对于lambda=2，也会发生分解为两种不同组成的向列态，介于一个上临界点和一个paranematic-向列相-向列相三相点之间。增加磁场强度会导致共存区域缩小。在足够高的磁场强度下，会诱导出一个不混溶闭合环，并在双临界点以上，系统变为均匀的向列相，此时相共存消失。对于lambda=2.5，除了paranematic-向列相共存外，还存在向列相-向列相共存，且该共存持续存在，因此不会终止于临界点。在相图中存在不混溶闭合环的情况下，沿双节线的各组分的部分取向序参数随组成变化很大，并且当闭合环存在时，各组分的参数平滑连接。 显示英文摘要

摘要： Using fundamental measure density functional theory we investigate paranematic-nematic and nematic-nematic phase coexistence in binary mixtures of circular platelets with vanishing thicknesses. An external magnetic field induces uniaxial alignment and acts on the platelets with a strength that is taken to scale with the platelet area. At particle diameter ratio lambda=1.5 the system displays paranematic-nematic coexistence. For lambda=2, demixing into two nematic states with different compositions also occurs, between an upper critical point and a paranematic-nematic-nematic triple point. Increasing the field strength leads to shrinking of the coexistence regions. At high enough field strength a closed loop of immiscibility is induced and phase coexistence vanishes at a double critical point above which the system is homogeneously nematic. For lambda=2.5, besides paranematic-nematic coexistence, there is nematic-nematic coexistence which persists and hence does not end in a critical point. The partial orientational order parameters along the binodals vary strongly with composition and connect smoothly for each species when closed loops of immiscibility are present in the corresponding phase diagram.