Charles E. Kaufman Foundation

2020 New Initiative Grant

Aditya Khair, Ph.D. (PI)  Professor, Department of Chemical Engineering, Carnegie Mellon University  

Lauren Zarzar, Ph.D. (co-investigator)  Assistant Professor, Department of Chemistry, Penn State University

Physicochemical communication between active droplets


The goal of this proposal is to quantify physicochemical communication and propulsion of active droplets. Active droplets are emerging in the scientific and engineering communities as model systems to analyze pattern formation and collective dynamics in soft materials. In particular, we are motivated by the recent discovery from Zarzar’s group of “communication-induced propulsion” between chemically-distinct micron-scale oil drops undergoing solubilization in an aqueous micellar solution. This is a fascinating instance of a purely chemical system exhibiting dynamics traditionally associated with living matter, such as flocks of birds or bacterial colonies. However, a quantitative modeling framework for the droplet propulsion is lacking. There is a pressing need to develop such a model, to enable a priori design of active droplets as building blocks for adaptive, functional microstructures. Our work will fill this knowledge gap via theory, computation and experiment, leveraging the interdisciplinary skillset of the investigators. We will focus on fundamental, paradigmatic active droplet phenomena, including communication-induced propulsion; self-propulsion via internal symmetry breaking; and collective self-organization and active phase separation. Our findings will transform the state-of-the-art understanding of active droplet phenomena by delivering a detailed, mechanistic understanding of active droplet propulsion and interactions. 

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