(713h) Linking Adhesive Emulsions Behaviour in Microfluidic Devices to Direct Force Measurements between Drop Pairs

Adhesive emulsions are systems with attractive interactions between drops in which aggregation, rather than coalescence, is prevalent. Adhesive interactions between drops control processes such as gel formation, fluid microstructure and the deposition of coatings as well as play a crucial role in governing responsive complex fluids (e.g. formulated products in food, personal care products, pharmaceutical formulations). This talk will focus on polymer surfactant complexes, due to their ability to control both solution and surface properties as well as form aggregated emulsions where drops stick or adhere rather than coalesce within a system. To understand these interactions one can employ direct force methods such as Atomic Force Microscopy (AFM) that offer exceptional accuracy, but are often time-consuming or limiting when attempting to examine a large number of parameters or solution conditions. Whereas microfluidics is a commonly used technique for the generation and investigation of drops behaviour at many solution conditions, but drop collision behaviour is often dictated by hydrodynamic interactions, not interfacial forces. In this work, we compare the adhesive interactions between polymer-surfactant coated drops measured via AFM to the behaviour of a novel microfluidic device capable of forming chains of drops based on the surface forces acting between drops under dynamic flow conditions. The implications of correlating adhesive interactions with solution conditions and molecular composition at a higher throughput scale using this combination of methods will be discussed.