STABILITY OF MONODISPERSE ZINC-SULFIDE COLLOIDAL DISPERSIONS
STABILITY OF MONODISPERSE ZINC-SULFIDE COLLOIDAL DISPERSIONS
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DOI：
10.1021/la00010a011
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发表时间：
1995-10-01
期刊：
影响因子：
3.9
通讯作者：
GONZALEZCABALLERO, F
中科院分区：
文献类型：
--
作者：
DURAN, JDG;GUINDO, MC;GONZALEZCABALLERO, F
本文研究了单分散球形硫化锌胶体颗粒在NaCl和CaCl_2溶液中的稳定性。所谓的扩展DLVO理论的稳定性是用来解释的数据。在该模型中，建议必须考虑刘易斯酸碱（AB）相互作用，以更好地解释ZnS胶体分散体的稳定性。理论的相互作用能-距离曲线进行计算和比较实验测定的悬浮液的稳定性，从它们的吸光度和颗粒直径的时间演变。以前，zeta电位的颗粒和它们的表面自由能组件被确定为电解质浓度的函数，分别使用，电泳迁移率测量和薄层芯吸法。NaCl浓度对颗粒的zeta电位的影响是典型的中性电解质，而Ca 2+阳离子似乎专门与ZnS表面相互作用。浓度约为10（-2）M时，悬浮液的稳定性最低，而较高浓度似乎可稳定悬浮液。在计算了粒子的表面自由能分量后，计算了不同粒子间距下的相互作用势能曲线。经典和扩展DLVO模型的预测和实验稳定性数据之间进行了比较。当使用后一种模型时，发现理论和实验结果之间有很好的定性一致性。因此，颗粒之间的（刘易斯）酸碱相互作用的列入是一个有用的工具，以充分描述ZnS悬浮液的稳定性。结果支持了以前的研究结果（货车Oss，C. J.道：等人，Clays Clay Min.1990，38，151）关于将酸碱（刘易斯）力添加到静电力和Lifshitz-van der Waals力的适合性，以具有能够预测胶体悬浮液行为的许多方面的强大理论。
The stability of monodisperse, spherical colloidal particles of zinc sulfide, in the presence of NaCl and CaCl2 solutions, has been studied in this work. The so-called extended DLVO theory of stability is used to explain the data. In this model, it is proposed that Lewis acid-base (AB) interactions have to be considered for better explaining the stability of ZnS colloidal dispersions. Theoretical interaction energy-distance curves are computed and compared to experimental determinations of the stability of the suspensions, obtained from time evolution of both their optical absorbance and particle diameter. Previously, the zeta potential of the particles and their surface free-energy components were determined as a function of electrolyte concentration, using, respectively, electrophoretic mobility measurements and the thin-layer wicking method. The effect of NaCl concentration on the zeta potential of the particles is typical of indifferent electrolytes, whereas Ca2+ cations appear to specifically interact with the ZnS surface. The stability of the suspensions is lowest for concentrations around 10(-2) M, whereas higher concentrations seem to stabilize the suspensions. After calculation of the surface free-energy components of the particles, potential energy of interaction curves are computed for different interparticle distances. A comparison is carried out between the predictions of both classical and extended DLVO models and experimental stability data. A good qualitative agreement between theoretical and experimental results is found when the latter model is used. The inclusion of(Lewis) acid-base interactions between the particles is thus a useful tool to adequately describe the stability of ZnS suspensions. The results support the previous findings (van Oss, C. J.; et al. Clays Clay Min. 1990, 38, 151) on the suitability of adding acid-base (Lewis) forces to electrostatic and Lifshitz-van der Waals forces to have a powerful theory capable of predicting many aspects of the behavior of colloidal suspensions.