Li Xiaofei, Lettieri S, Wentzel N, Gunton J D
Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
J Chem Phys. 2008 Oct 28;129(16):164113. doi: 10.1063/1.2999608.
We obtain accurate fluid-fluid coexistence curves for a recent simple model of interacting nanoparticles that includes the effects of ion-dispersion forces. It has been proposed that these ion-dispersion forces provide at least a partial explanation for the Hofmeister effect [M. Bostrom et al. Phys. Rev. Lett. 87, 168103 (2001)]. We study a model of aluminum oxide nanoparticle [Deniz et al., Colloids Surf. A 319, 98 (2008)] for three different electrolyte solutions with added salt type being sodium chloride, sodium iodide, and a nonpolarizable salt. We observe that the fluid-fluid coexistence curves depend substantially on the identity of added salt; this provides an efficient way of tuning the phase behavior of nanoparticles. The methods we employ include finite-size scaling (FSS), multicanonical histogram reweighting, and Gibbs ensemble methods. We show that, as expected, all three cases belong to the Ising universality class. The scaling fields and critical point parameters are obtained in the thermodynamic limit of infinite system size by extrapolation of our FSS results.
我们针对一种近期的相互作用纳米颗粒简单模型获得了精确的流体-流体共存曲线，该模型包含离子色散力的影响。有人提出，这些离子色散力至少为霍夫迈斯特效应提供了部分解释[M. 博斯特罗姆等人，《物理评论快报》87, 168103 (2001)]。我们研究了氧化铝纳米颗粒模型[德尼兹等人，《胶体与界面科学A》319, 98 (2008)]，针对三种不同的电解质溶液，添加的盐类型分别为氯化钠、碘化钠和一种不可极化盐。我们观察到，流体-流体共存曲线很大程度上取决于添加盐的种类；这提供了一种调节纳米颗粒相行为的有效方法。我们采用的方法包括有限尺寸标度（FSS）、多正则直方图重加权和吉布斯系综方法。我们表明，正如预期的那样，所有三种情况都属于伊辛普适类。通过对我们的FSS结果进行外推，在无限系统尺寸的热力学极限下获得了标度场和临界点参数。
