Fantoni Riccardo, Gazzillo Domenico, Giacometti Achille, Sollich Peter
Istituto Nazionale per la Fisica della Materia and Dipartimento di Chimica Fisica, Università Ca' Foscari di Venezia, Santa Marta DD 2137, I-30123 Venezia, Italy.
J Chem Phys. 2006 Oct 28;125(16):164504. doi: 10.1063/1.2358136.
We study the effects of size polydispersity on the gas-liquid phase behavior of mixtures of sticky hard spheres. To achieve this, the system of coupled quadratic equations for the contact values of the partial cavity functions of the Percus-Yevick solution [R. J. Baxter, J. Chem. Phys. 49, 2770 (1968)] is solved within a perturbation expansion in the polydispersity, i.e., the normalized width of the size distribution. This allows us to make predictions for various thermodynamic quantities which can be tested against numerical simulations and experiments. In particular, we determine the leading order effects of size polydispersity on the cloud curve delimiting the region of two-phase coexistence and on the associated shadow curve; we also study the extent of size fractionation between the coexisting phases. Different choices for the size dependence of the adhesion strengths are examined carefully; the Asakura-Oosawa model [J. Chem. Phys. 22, 1255 (1954)] of a mixture of polydisperse colloids and small polymers is studied as a specific example.
我们研究了尺寸多分散性对粘性硬球混合物气液相行为的影响。为此，在多分散性（即尺寸分布的归一化宽度）的微扰展开范围内，求解了Percus-Yevick解[R. J. Baxter, J. Chem. Phys. 49, 2770 (1968)]的部分空穴函数接触值的耦合二次方程组。这使我们能够对各种热力学量进行预测，并可与数值模拟和实验进行对比验证。特别地，我们确定了尺寸多分散性对界定两相共存区域的云曲线以及相关阴影曲线的主导阶效应；我们还研究了共存相之间尺寸分级的程度。仔细研究了粘附强度对尺寸依赖性的不同选择；以多分散胶体和小聚合物混合物的朝仓-大泽模型[J. Chem. Phys. 22, 1255 (1954)]作为具体实例进行了研究。
