Microscale Flows to Engineer Fluid Interfaces Containing Macromolecular and Colloidal Species

Carnegie Mellon University, Pittsburgh PA

Investigators

Abstract

The goal of the proposed work is to develop experimental methods for controlling the presence of adsorbed species at mobile (flowing) interfaces. This work is guided by the framework of a simplified theoretical model that has been developed for interface breakup in the presence of surfactants. The intellectual merit of this work is the development of tools to tackle problems involving coupled surfactant dynamics and fluid flow. We will develop these tools through detailed experimental analysis and modeling of a specific example: surfactant-mediated tipstreaming for formation of submicron droplets. These studies will help elucidate the critical mechanisms controlling a broader set of interfacial flow applications, enabling greater control over key processes. This framework will enable the engineering of mobile interfaces, and we will use this capability to develop novel methods for quantifying the kinetics of ad/desorption of more complex molecules (i.e, biomolecules, macromolecules and colloids) and tackle a specific application, quantification of the kinetics of denaturation of proteins at interfaces. The results of this work will have broad technological impact because of the importance of surfactant-laden multiphase flows in technologies such as emulsification, spraying and coatings and in emerging applications such as ink-jet printing of new materials or two-phase flows in microfluidic devices, which have been exploited to synthesize monodisperse droplets, bubbles, colloidal particles, and other novel colloidal assemblies. The interfacial and microfluidic flows characterized by this work will have broad educational impact by providing highly visual images and fluid dynamics examples that can feed into the major outreach, undergraduate research, and course development activities of the two PIs.