Kline SR, Kaler EW
Department of Chemical Engineering, University of Delaware, Delaware, Newark, 19716
J Colloid Interface Sci. 1998 Jul 15;203(2):392-401. doi: 10.1006/jcis.1998.5543.
We have investigated the colloidal stability and interactions in a mixture of colloidal silica (LudoxTM) and an oil-in-water microemulsion (AOT/decane/brine). Stable silica-microemulsion mixtures containing large fractions of dispersed phase (phioil + phiLudox > 0.36) can be prepared. For fixed silica and AOT concentrations, the addition of decane increases the size of the microemulsion droplets. Since the surfactant concentration remains constant, this droplet growth is balanced by a decrease in the number density of droplets. Partial structure factors for the mixture are extracted from sets of small-angle neutron scattering (SANS) data using a solvent contrast variation technique. The extracted partial structure factors are compared qualitatively to model calculations for a multicomponent sticky hard sphere (SHS) fluid. A shallow contact potential (approximately 2.6 kT) between the Ludox particles is necessary to obtain agreement between model and experiment in the low-q region of the partial structure factors. The magnitude of this contact potential does not change with decane concentration, in agreement with the macroscopic observation that there is no observable change in the stability of these silica-microemulsion mixtures. Copyright 1998 Academic Press.
我们研究了胶体二氧化硅（LudoxTM）与水包油微乳液（AOT/癸烷/盐水）混合物中的胶体稳定性和相互作用。可以制备出含有大量分散相（φ油 + φ二氧化硅 > 0.36）的稳定二氧化硅 - 微乳液混合物。对于固定的二氧化硅和AOT浓度，癸烷的加入会增大微乳液滴的尺寸。由于表面活性剂浓度保持恒定，这种液滴生长会被液滴数密度的降低所平衡。使用溶剂对比度变化技术从一组小角中子散射（SANS）数据中提取混合物的部分结构因子。将提取的部分结构因子与多组分粘性硬球（SHS）流体的模型计算进行定性比较。为了在部分结构因子的低q区域使模型与实验结果相符，Ludox颗粒之间需要一个浅的接触势（约2.6 kT）。该接触势的大小不随癸烷浓度变化，这与这些二氧化硅 - 微乳液混合物稳定性无明显变化的宏观观察结果一致。版权所有1998年学术出版社。
