Chemically Tuning Attractive and Repulsive Interactions between Solubilizing Oil Droplets. (4th July 2022)

• Record Type: Journal Article
• Authors: Wentworth, Ciera M.; Castonguay, Alexander C.; Moerman, Pepijn G.; Meredith, Caleb H.; Balaj, Rebecca V.; Cheon, Seong Ik; Zarzar, Lauren D.
• Is Part Of: Angewandte Chemie. Volume 134:Number 32(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-04
• Subjects: Active Matter -- Emulsions -- Interfaces -- Micelles -- Solubilization -- Surfactants; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202204510
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: 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. Abstract : 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 is characterized systematically. Three regimes corresponding to droplet "attraction", "repulsion", or "inactivity" are identified and the chemical trends leading to these behaviors are discussed.