Synergistic stabilization of emulsions by poly(oxypropylene)diamine and Laponite particles
Synergistic stabilization of emulsions by poly(oxypropylene)diamine and Laponite particles
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DOI：
10.1016/j.colsurfa.2009.11.002
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发表时间：
2010-01-15
影响因子：
5.2
通讯作者：
Sun, Dejun
中科院分区：
文献类型：
--
作者：
Wang, Jun;Liu, Guopeng;Sun, Dejun
制备了在无电解质存在下用聚氧丙烯二胺原位改性的Laponite颗粒稳定的液体石蜡-水乳液。首先，详细研究了Laponite分散体在增加浓度的二胺存在下的特性。红外吸收光谱和zeta电位测量证实了二胺在Laponite颗粒上的吸附。吸附等温线进一步表明高度亲合的L-型行为和推导出的二胺分子位于与两个端基锚定在颗粒表面和聚（氧丙烯）链暴露于水溶液。然后，使用二胺改性的颗粒制备乳液。二胺和Laponite颗粒单独是无效的乳化剂，但它们之间表现出很强的协同作用。激光诱导荧光共聚焦显微照片和TEM观察证明了粒子在乳液表面的排列，也揭示了稳定性机制。还用光学显微镜和液滴尺寸测量探索了乳液稳定性。随着二胺浓度的增加，乳液分层的程度降低，并且液滴尺寸相应地降低。在一定的低二胺浓度下，乳液分层的程度降低到最小，并且相应的液滴尺寸最小。当二胺浓度进一步增加时，该最佳乳液状态不变。(C)2009 Elsevier B. V.保留所有权利。
Liquid paraffin-water emulsions were prepared which were stabilized by Laponite particles in situ modified with poly(oxypropylene)diamines in the absence of electrolytes. First, the characteristics of the Laponite dispersions in the presence of increasing concentrations of diamines were studied in detail. Infrared absorption spectra and zeta potential measurements confirm the adsorption of diamines on the Laponite particles. Adsorption isotherms further indicate highly affinitive L-type behaviors and the diamine molecules are deduced to lie with both end groups anchored on the particle surface and the poly(oxypropylene) chain exposed to the aqueous solution. Then, emulsions were prepared using the diamine-modified particles. Diamines and Laponite particles alone are ineffective emulsifiers, but a strong synergism is exhibited between them. Laser-induced fluorescent confocal micrographs and TEM observations demonstrate the arrangement of the particles on the emulsion surfaces and also reveal the stability mechanisms. The emulsion stability was also explored with optical microscopy and droplet size measurements. As the diamine concentration increases, the extent of emulsion creaming decreases and the droplet size correspondingly decreases. At a certain low diamine concentration, the extent of emulsion creaming decreases down to a minimum and the corresponding droplet size is the smallest. This optimal emulsion state is unchanged when the diamine concentration is further increased. (C) 2009 Elsevier B.V. All rights reserved.