(67e) Surface Anisotropic Particles, Capillary Interactions, and Dynamics of Fluid Interfaces

Presence of complex solutions composed of fluids, ions, surfactant molecules, and colloidal particles is commonplace in problems relevant to materials discovery and manufacturing. Such multicomponent fluidic systems are often confined by interfaces in processes associated with the water-energy nexus as well, for example, in membrane separations and subsurface energy recovery and storage. To make matters more intricate, fluid interfaces are not static and are constantly subject to external disturbances such as thermal gradients, imposed stresses, and changes in composition. Given the environmental and economic impact of the subject matter, it is important to advance our fundamental quantitative understanding of the complex interfacial systems just summarized, with the goal of ultimately predicting and controlling their behavior in relevant high-tech applications. In this presentation, I will review our recent findings on how particle surface anisotropy influences the stability and rheology of fluid interfaces. Our investigations demonstrate that particles’ amphiphilicity is a crucial factor governing their orientation at the interface, which in turn dictates the complexity of capillary interactions present at a fluid interface and its ensuing mechanical properties. Understanding these concepts is key in designing interfacial systems, by engineering the surface attributes of particles, and is essential for numerous applications of soft matter, as listed in the New Directions for Chemical Engineering.