MSE Seminar Series: Lauren Zarzar (Penn State)

Description

Self-organization and behavior of non-equilibrium active droplets

Life is sustained by exploiting nano/microscale soft structures and interfaces to direct the non-equilibrium chemical processes that govern motion, organization, and growth. Fundamentally understanding how materials self-organize under dissipative conditions in synthetic systems, such as chemically minimal colloids, may provide insight into the matter-to-life transition. I will present our recent work aimed at understanding the non-equilibrium properties of emulsions and liquid interfaces, including the chemotactic motions of droplets, solubilization mechanisms, and emergent collective phenomena. I will discuss chemomechanical frameworks for generating oil-in-water droplet behaviors like self-propulsion, attraction/repulsion, and non-reciprocal interactions (e.g. chasing) of tunable strength and directionality. The interfaces present in the emulsion, the “species” of droplet present, and the structure of complex droplets, is observed to be critical to active behaviors and self-organization. I will propose ideas for how the non-equilibrium transport at liquid interfaces may play a role in governing the active behaviors of solubilizing droplets. We believe that the study of such active solubilizing droplets provides a means to both uncover a chemically-tunable platform for probing active matter but also contributes to fundamental understanding of how fluid phases and interfaces behave when far from equilibrium.
 

Bio:
Dynamic materials that sense and adapt to their surroundings are primed to be integral components of future technologies. Such systems often require precise chemo-mechanical coordination between multiple materials working cooperatively in order to achieve the proper functionality. Therefore, in addition to the exploration of novel mechanisms coupling these chemical and mechanical cues, it will also be critical to develop prototyping approaches that facilitate the integration of a myriad of materials, especially at nano and micrometer length scales. In the Zarzar Lab, we explore a multitude of platforms including both hard and soft materials. For example, we study: direct laser writing of polymers, metals, and oxides for 2D and 3D nano/microscale patterning; dynamically reconfigurable soft materials, such as emulsions and polymers, with functions such as tunable lenses, sensors, and triggered release.