Moncho-Jordá A, Dzubiella J, Hansen J P, Louis A A
Departamento de Física Aplicada, Universidad de Granada, Facultad de Ciencias, Campus Fuentenueva S/N, 18071 Granada, Spain.
J Phys Chem B. 2005 Apr 14;109(14):6640-9. doi: 10.1021/jp045841x.
Interfacial properties of colloid-polymer mixtures are examined within an effective one-component representation, where the polymer degrees of freedom are traced out, leaving a fluid of colloidal particles interacting via polymer-induced depletion forces. Restriction is made to zero-, one-, and two-body effective potentials, and a free energy functional is used that treats colloid excluded volume correlations within Rosenfeld's fundamental measure theory, and depletion-induced attraction within first-order perturbation theory. This functional allows a consistent treatment of both ideal and interacting polymers. The theory is applied to surface properties near a hard wall, to the depletion interaction between two walls, and to the fluid-fluid interface of demixed colloid-polymer mixtures. The results of the present theory compare well with predictions of a fully two-component representation of mixtures of colloids and ideal polymers (the Asakura-Oosawa model) and allow a systematic investigation of the effects of polymer-polymer interactions on interfacial properties. In particular, the wall surface tension is found to be significantly larger for interacting than for ideal polymers, whereas the opposite trend is predicted for the fluid-fluid interfacial tension.
在一种有效的单组分表示法中研究了胶体 - 聚合物混合物的界面性质，其中聚合物的自由度被消除，留下了通过聚合物诱导的排空力相互作用的胶体粒子流体。限制为零体、一体和二体有效势，并使用一个自由能泛函，该泛函在罗森菲尔德的基本度量理论中处理胶体排除体积相关性，并在一阶微扰理论中处理排空诱导的吸引力。这个泛函允许对理想聚合物和相互作用聚合物进行一致的处理。该理论应用于硬壁附近的表面性质、两壁之间的排空相互作用以及混合的胶体 - 聚合物混合物的流体 - 流体界面。本理论的结果与胶体和理想聚合物混合物的完全双组分表示法（朝仓 - 大泽模型）的预测结果比较良好，并允许对聚合物 - 聚合物相互作用对界面性质的影响进行系统研究。特别是，发现相互作用聚合物的壁表面张力明显大于理想聚合物的壁表面张力，而流体 - 流体界面张力则呈现相反的趋势。
