(425a) Capillary Foams: How a Small Amount of Oil Can Make a Big Difference

Today, humanity faces unprecedented challenges in managing the word’s critical energy, water, food, and healthcare needs. While there are many aspects to these challenges, one issue that is certain to play a pivotal role in any solution is new materials. Directed assembly provides a “bottom-up” approach to create novel, functional materials with well-defined properties and functionality from nanoscale building blocks. Here, I will present a new class of colloidal materials, capillary foams, through directed assembly in a colloidal four-phase systems. Capillary foams are formed by frothing a suspension of colloidal particles in the presence of a small amount of oil (less than 1 wt%). I will discuss our fundamental understanding of the formation mechanism and explain the huge difference that a small amount of oil can make in these foams. The presence of so many phases (and their interfaces) offers a wealth of processing opportunities for the development of new materials with interesting chemical or mechanical properties and transport characteristics. Looking beyond the fundamental studies, I will discuss some of the application opportunities for capillary foams, for instance in the fabrication of loadbearing, lightweight, or intensely colored porous materials, enhanced oil recovery, advanced froth flotation, wastewater treatment, and oil spill remediation. Capillary foams can be used for engineering a wide range of functional materials targeting energy and environment problems that can better serve our society.