Adsorption of nonionic surfactants at fluid-fluid interfaces: Importance in the coalescence of bubbles and drops
Adsorption of nonionic surfactants at fluid-fluid interfaces: Importance in the coalescence of bubbles and drops
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DOI：
10.1016/j.ces.2007.03.002
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发表时间：
2007-06-01
影响因子：
4.7
通讯作者：
Ghosh, P.
中科院分区：
文献类型：
--
作者：
Giribabu, K.;Ghosh, P.
表面活性剂的主要工业应用与乳液和泡沫的稳定性有关，这直接取决于液滴和气泡的聚结速率。表面活性剂分子吸附在液-液和气-液界面上，防止液滴和气泡彼此聚结。因此，将表面活性剂的吸附与聚结所需的时间联系起来很重要。在这项工作中，我们研究了三种非离子表面活性剂 Tween 20、Triton X-100 和 Span 80 在空气-水和水-甲苯界面的吸附。研究了表面张力和界面张力随表面活性剂浓度的变化，并使用从朗缪尔吸附等温线导出的表面状态方程对数据进行拟合。我们研究了在这三种表面活性剂存在下水滴在甲苯中的二元聚结。研究了在水溶性表面活性剂 Tween 20 和 Triton X-100 存在下气泡在平坦空气-水界面处的聚结。使用聚结随机模型来拟合聚结时间分布。讨论了模型参数的意义。 (C) 2007 Elsevier Ltd. 保留所有权利。
Major industrial applications of surfactants are related to the stability of emulsions and foams, which is directly dependent on the rate of coalescence of drops and bubbles. Surfactant molecules adsorb at the liquid-liquid and gas-liquid interfaces and prevent the drops and bubbles from coalescing with one another. Therefore, it is important to correlate the adsorption of surfactant with the time required for coalescence. In this work, we have studied the adsorption of three nonionic surfactants, Tween 20, Triton X-100 and Span 80 at air-water and water-toluene interfaces. The variation of surface and interfacial tension with the concentration of surfactant was studied and the data were fitted using a surface equation of state derived from the Langmuir adsorption isotherm. We have studied binary coalescence of water drops in toluene in presence of these three surfactants. Coalescence of air bubbles at flat air-water interface was studied in presence of the water-soluble surfactants, Tween 20 and Triton X-100. A stochastic model for coalescence was used to fit the coalescence time distributions. The significance of the model parameters was discussed. (C) 2007 Elsevier Ltd. All rights reserved.