Rodier Bradley, de Leon Al, Hemmingsen Christina, Pentzer Emily
Department of Chemistry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States.
ACS Macro Lett. 2017 Nov 21;6(11):1201-1206. doi: 10.1021/acsmacrolett.7b00648. Epub 2017 Oct 16.
Emulsions are important in numerous fields, including cosmetics, coatings, and biomedical applications. A subset of these structures, oil-in-oil emulsions, are especially intriguing for water sensitive reactions such as polymerizations and catalysis. Widespread use and application of oil-in-oil emulsions is currently limited by the lack of facile and simple methods for preparing suitable surfactants. Herein, we report the ready preparation of oil-in-oil emulsions using 2D nanomaterials as surfactants at the interface of polar and nonpolar organic solvents. Both the edges and basal plane of graphene oxide nanosheets were functionalized with primary alkyl amines and we demonstrated that the length of the alkyl chain dictates the continuous phase of the oil-in-oil emulsions (i.e., nonpolar-in-polar or polar-in-nonpolar). The prepared emulsions are stable at least 5 weeks and we demonstrate they can be used to compartmentalize reagents such that reaction occurs only upon physical agitation. The simplicity and scalability of these oil-in-oil emulsions render them ideal for applications impossible with traditional oil-in-water emulsions, and provide a new interfacial area to explore and exploit.
乳液在众多领域都很重要，包括化妆品、涂料和生物医学应用。这些结构的一个子集，即油包油乳液，对于诸如聚合反应和催化等对水敏感的反应尤其具有吸引力。目前，油包油乳液的广泛使用和应用受到缺乏简便方法制备合适表面活性剂的限制。在此，我们报告了在极性和非极性有机溶剂的界面处使用二维纳米材料作为表面活性剂来制备油包油乳液的简便方法。氧化石墨烯纳米片的边缘和基面都用伯烷基胺进行了功能化，并且我们证明了烷基链的长度决定了油包油乳液的连续相（即非极性在极性中或极性在非极性中）。所制备的乳液至少稳定5周，并且我们证明它们可用于分隔试剂，使得反应仅在物理搅拌时发生。这些油包油乳液的简单性和可扩展性使其成为传统水包油乳液无法实现的应用的理想选择，并提供了一个新的可探索和利用的界面区域。
