Manipulation of Interfacial Processes, Reactions, and Feedback within Reconfigurable Multiphase Fluids (II.A.1.a.i.4)
Abstract
Dynamic materials that sense and adapt to their surroundings via chemo-mechanical feedback are primed to be integral components of future technologies. Nature serves as inspiration for the development of active matter, exemplifying effective design principles and approaches. A core characteristic underpinning the adaptiveness of natural systems is the ability to transmit complex chemical and mechanical signals via diverse pathways. Such pathways are made possible by spatially controlled chemistry taking place within a heterogeneous chemical environment. One approach to spatially controlling chemistry is to physically separate, or compartmentalize, reagents within different phases thereby localizing reactions at interfaces. Reactions will only occur where the reagents come into contact at the interface or when one reagent is selectively transported across the interface. Then, by manipulating the location, area, or selectivity of the interfaces within a system, the reactions will respond spatiotemporally. Dramatically different properties may emerge that were impossible in a homogeneous reaction environment, including chemo-mechanical cascades and feedback. Complex fluids present a unique reaction environment to explore such phenomena because of the multiple phases and many interfaces present where reactions can occur. A complex fluid is any mixture of coexisting phases; this proposal will be specifically focusing on emulsions, which are mixtures of immiscible liquids. What if the areas of liquid-liquid interfaces in a complex emulsion could be dynamically altered - do the reaction locations and rates change in a predictable and controllable manner? Reconfigurable complex emulsion could be a platform for the dynamic manipulation of chemical reactions, chemo-mechanical feedback, and signal amplification. Previously, the PI developed a method for fabricating and reconfiguring the morphology of multiphase liquid droplets which serves as the foundation for this proposal. This approach takes advantage of droplet shape changes (e.g. between double emulsion and Janus droplet morphologies), that occur when the interfacial tensions around the droplet are altered. By externally controlling the interfacial tensions at the droplet surface, the liquid-liquid interfaces within the emulsion can be extensively rearranged and their areas modified, providing the general approach for manipulating interfacial reactions in multiphase fluids. While the droplet reconfiguration mechanism is well established, significant questions remain regarding the properties and utility of these droplets with regards to the manipulation of interfacial reactions and feedback. Along those lines, this proposal will address three broad, interrelated aims. Aim I addresses reaction and transport processes across the droplet-continuous phase interface and how these processes are tied to droplet morphology. Aim 2 focuses on the mechanisms of inter-droplet "communication" or transport and how it can be dynamically controlled with droplet morphology. Aim 3 ties together Aims 1 and 2 by investigating feedback; when drop-drop processes can be related to drop-outer phase processes that drive changes in droplet morphology, a complex chemo-mechanical network may form that ultimately leads to signal amplification and feedback. It is anticipated that the development of signal transduction pathways predicated on this unique ability to reconfigure fluid-fluid interfaces would enable a new paradigm for responsive or active materials. Such materials would have far reaching implications aligning with the Department of Defense and the Anny s interests including chemical and biological sensors, chemo-mechanical materials, dynamic camouflage, remote diagnostics, triggered release, and adaptive optics.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810414
Entities
People
- Lauren D Zarzar
Organizations
- Army Contracting Command
- Pennsylvania State University
- United States Army