Microstructure and dynamics of Janus particles in a phase separating medium.
Microstructure and dynamics of Janus particles in a phase separating medium.
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DOI：
10.1063/1.5008400
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发表时间：
2018-01
期刊：
影响因子：
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通讯作者：
E. Semeraro;R. Dattani;T. Narayanan
中科院分区：
文献类型：
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作者：
E. Semeraro;R. Dattani;T. Narayanan
研究了Janus胶体颗粒在准二元混合液中发生相分离时的相互作用和动力学演化。实验系统由分散在3-甲基吡啶、水和重水的混合物中的二氧化硅-镍Janus颗粒组成。用超小角X射线散射和超小角X射线光子相关谱分别研究了胶体的微观结构和动力学。所观察到的静态和动态行为显着不同的Stöber二氧化硅胶体在这种混合物中。Janus粒子在低于共存温度时表现出缓慢的聚集，并且在溶剂混合物的相分离时变得具有强烈的吸引力。在两相区中，颗粒倾向于显示出类似于表面活性剂的行为，二氧化硅和镍表面可能分别优选富含水和3-甲基吡啶的相。虽然发病的扩散泳运动是明显的动力学，它逐渐抑制在调查胶体体积分数的颗粒聚集。
The evolution of interactions and dynamics of Janus colloidal particles suspended in quasi-binary liquid mixtures undergoing phase separation is presented. The experimental system consisted of silica-nickel Janus particles dispersed in mixtures of 3-methylpyridine, water, and heavy water. Colloidal microstructure and dynamics were probed by ultra-small-angle X-ray scattering and ultra-small-angle X-ray photon correlation spectroscopy, respectively. The observed static and dynamic behaviors are significantly different from those found for Stöber silica colloids in this mixture. The Janus particles manifest a slow aggregation below the coexistence temperature and become strongly attractive upon phase separation of the solvent mixture. In the two-phase region, particles tend to display surfactant-like behavior with silica and nickel surfaces likely preferring water and 3-methylpyridine rich phases, respectively. While the onset of diffusiophoretic motion is evident in the dynamics, it is gradually suppressed by particle clustering at the investigated colloid volume fractions.