Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.
Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
Angew Chem Int Ed Engl. 2022 Aug 8;61(32):e202204510. doi: 10.1002/anie.202204510. Epub 2022 Jun 29.
Micellar solubilization is a transport process occurring in surfactant-stabilized emulsions that can lead to Marangoni flow and droplet motility. Active droplets exhibit self-propulsion and pairwise repulsion due to solubilization processes and/or solubilization products raising the droplet's interfacial tension. Here, we report emulsions with the opposite behavior, wherein solubilization decreases the interfacial tension and causes droplets to attract. We characterize the influence of oil chemical structure, nonionic surfactant structure, and surfactant concentration on the interfacial tensions and Marangoni flows of solubilizing oil-in-water drops. Three regimes corresponding to droplet "attraction", "repulsion" or "inactivity" are identified. We believe these studies contribute to a fundamental understanding of solubilization processes in emulsions and provide guidance as to how chemical parameters can influence the dynamics and chemotactic interactions between active droplets.
胶束增溶是一种在表面活性剂稳定的乳液中发生的输运过程，可导致马兰戈尼流和液滴运动。由于增溶过程和/或增溶产物提高了液滴的界面张力，活性液滴表现出自推进和成对排斥。在这里，我们报告了具有相反行为的乳液，其中增溶降低了界面张力并导致液滴相互吸引。我们研究了油的化学结构、非离子表面活性剂结构和表面活性剂浓度对增溶油包水乳滴的界面张力和马兰戈尼流的影响。确定了三个对应于液滴“吸引”、“排斥”或“不活跃”的区域。我们相信这些研究有助于深入了解乳液中的增溶过程，并为化学参数如何影响活性液滴之间的动力学和趋化相互作用提供指导。
