Title:

Surfactants, colloids, and electrolytes: Complex fluids for energy and the environment.

Speaker:

Dr. Fernando Coleto

Affiliation:

Princeton University

When:

Tuesday, January 21, 2025 at 11:00:00 AM   Add to Calendar

Where:

Boggs Building, Room 34-7

Host:

David Hu
hu@me.gatech.edu

Abstract

Transport in fluids mediates countless physical processes key to sustainability, ranging from the spread of harmful microplastics to the mining of lithium for batteries. Engineering these transport processes into applications often requires an understanding of complex fluids, where the physicochemical interactions between microscopic constituents critically affect the macroscopic dynamics. In this talk, I share three examples of complex fluids from my research, which highlight how uncovering fundamental physical mechanisms can directly inform new technologies in energy and the environment. First, I discuss surfactants, chemicals that adsorb onto interfaces between fluids and profoundly alter their motion. My work has revealed that these substances play a central role in the performance of “superhydrophobic” textured coatings aimed at reducing hydrodynamic friction in applications like marine transportation. Through a combination of theory and confocal microscopy experiments, I identify a key length scale of physicochemical origin that faithfully predicts the effects of ambient surfactants on a given texture. Next, I will demonstrate how the spontaneous migration of colloids in chemical gradients, an effect known as diffusiophoresis, can be used to filter solid particles from water without membranes. I theoretically derive upper bounds for the efficiency of this separation process and demonstrate it using microfluidic experiments, paving the way towards new approaches to the remediation of microplastic pollutants. Finally, I illustrate the physics behind the evaporation of electrolytes, ionic solutions that can be found in nature in the form of brines. I show that this process, which is crucial for the extraction of minerals like lithium, can be dramatically boosted using porous materials that increase the evaporative surface area. Using continuum modeling, I determine the key parameters that control the rate of mineral extraction, and pinpoint possible pathways to enhance its efficiency and reduce its environmental impact.

Biography

Fernando Temprano-Coleto is a postdoctoral research associate at Princeton University. He earned his PhD in Mechanical Engineering from the University of California Santa Barbara with Frederic Gibou and Paolo Luzzatto-Fegiz, investigating the effects of surfactants on the drag reduction performance of superhydrophobic coatings. For his doctoral work, he was awarded the APS Gallery of Fluid Motion Award, the WAGS/ProQuest Distinguished Master’s Thesis Award, and the UCSB Mechanical Engineering Best PhD Dissertation Award. Currently, he works with Howard Stone studying transport processes mediated by complex fluids, including the separation of microplastics and the evaporative extraction from brines of minerals like lithium. At Princeton, Fernando has received a Distinguished Postdoctoral Fellowship from the Andlinger Center for Energy and the Environment, as well as an Exemplar Mentor Award from the McGraw Center for Teaching and Learning. His overarching research vision is to identify and investigate fundamental transport mechanisms key to advance the next generation of technologies in energy and the environment, using a combination of theory, experiments, and computation.

Notes

Refreshments will be served.