Djalali Saveh, Frank Bradley D, Zeininger Lukas
Department of Chemistry, Max Planck Institute of Colloids and Interfaces, Am Muehlenberg 1, 14476 Potsdam, Germany.
Soft Matter. 2020 Dec 14;16(46):10419-10424. doi: 10.1039/d0sm01724h. Epub 2020 Nov 6.
Characterization of surfactant effectiveness and thus an evaluation of their performance in a wide range of emulsion technologies requires a precise determination of key parameters including their critical micelle concentrations as well as their ability to lower the surface tension at interfaces. In this study, we describe a new approach to quantify marginal variations in interfacial tension of surfactant stabilized fluid interfaces. The method is based on a unique chemical-morphological coupling inside bi-phasic oil-in-water Janus emulsions that undergo dynamic morphological transitions in response to changes in the surfactant type, concentration, ratio, and configuration. Variations in Janus droplet morphologies are readily monitored in situ using a simple side-view imaging setup, resulting in a fast, convenient, cost-effective, time-, and sample-saving technique for the characterization of classical surfactant systems. In addition, the reported method facilitates monitoring of triggered changes in surfactant effectiveness, e.g. invoked by external triggers, and thus proves particularly useful for the in situ analysis of stimuli-responsive surfactants and emulsions.
表面活性剂有效性的表征以及对其在广泛乳液技术中性能的评估需要精确测定关键参数，包括其临界胶束浓度以及降低界面表面张力的能力。在本研究中，我们描述了一种量化表面活性剂稳定的流体界面界面张力微小变化的新方法。该方法基于双相水包油Janus乳液内部独特的化学 - 形态耦合，这种乳液会根据表面活性剂类型、浓度、比例和构型的变化发生动态形态转变。使用简单的侧视图成像装置可以很容易地原位监测Janus液滴形态的变化，从而形成一种快速、便捷、经济高效、节省时间和样品的经典表面活性剂体系表征技术。此外，所报道的方法有助于监测表面活性剂有效性的触发变化，例如由外部触发引起的变化，因此对于刺激响应性表面活性剂和乳液的原位分析特别有用。
