Liaoning Key Laboratory for Green Synthesis and Preparative Chemistry of Advanced Materials, College of Chemistry, Liaoning University, Shenyang 110036, China.
Liaoning Key Laboratory for Green Synthesis and Preparative Chemistry of Advanced Materials, College of Chemistry, Liaoning University, Shenyang 110036, China; State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
J Colloid Interface Sci. 2017 Dec 1;507:74-82. doi: 10.1016/j.jcis.2017.07.097. Epub 2017 Jul 27.
A type of ionic liquid functionalized high-aspect-ratio Janus SiO nanosheets (IL-Janus nanosheets), which possesses a side terminated by imidazolin salt groups and the opposite side terminated by phenyl groups, was prepared and its emulsification performance was investigated. The surface wettability of ionic liquid functionalized side could be tailored via simple anion exchanging, giving the amphiphilic or totally hydrophobic Janus nanosheets. The influence of several parameters including surface wettability, particle concentration, oil composition, oil-water ratio as well as initial location of the nanosheets on the stability, morphology and type of the Pickering emulsions (O/W or W/O) stabilized by the amphiphilic IL-Janus nanosheets was evaluated. The research results revealed that average emulsion droplets size was decreased with increase of nanosheets concentration below a concentration value but had almost no change beyond the concentration; catastrophic phase inversion phenomenon occurred by varying volume fraction of water phase in the oil-water systems, and transitional phase inversion could be achieved by in-situ exchanging Cl anion of the IL-Janus nanosheets with phosphomolybdate HPMoO. The responsiveness of Pickering emulsions towards phosphomolybdic acid is resulted from irreversible anion exchanging of Cl by HPMoO and the variation of surface wettability of the nanosheets.
一种离子液体功能化高纵横比的 JanusSiO 纳米片（IL-Janus 纳米片），其一侧末端由咪唑啉盐基团封端，另一侧末端由苯基封端，被制备并研究了其乳化性能。通过简单的阴离子交换，可以调节离子液体功能化侧的表面润湿性，得到具有两亲性或完全疏水性的 Janus 纳米片。研究了几种参数的影响，包括表面润湿性、颗粒浓度、油组成、油水比以及纳米片的初始位置对由两亲性 IL-Janus 纳米片稳定的 Pickering 乳液（O/W 或 W/O）的稳定性、形态和类型的影响。研究结果表明，在低于浓度值的纳米片浓度下，平均乳液液滴尺寸随纳米片浓度的增加而减小，但超过该浓度后几乎没有变化；通过改变油-水体系中水相的体积分数，会发生灾难性的相反转现象，而通过原位交换 IL-Janus 纳米片的 Cl 阴离子与磷钼酸 HPMoO，可实现过渡相反转。Pickering 乳液对磷钼酸的响应源于 Cl 与 HPMoO 的不可逆阴离子交换以及纳米片表面润湿性的变化。
