Norman J. Wagner, Ph.D.
Unidel Robert L. Pigford Chair in Chemical & Biomolecular Engineering, University of Delaware
Shear thickening fluids and their application as protective materials for first responders, athletes, and astronauts (and some recent work on “planetopolymers”).
Shear thickening colloidal and/or nanoparticle suspensions are commonly encountered in chemical and materials processing and are also the basis of a technology platform for advanced, field responsive nanocomposites. In this presentation, I will review some of the experimental methods and key results concerning the micromechanics of colloidal suspension rheology. Micromechanics is the ability to predict the rheological properties of complex systems from a colloidal or microscopic level description of the structure and forces. A fundamental understanding of colloidal suspension rheology and in particular, shear thickening, has been achieved through a combination of model system synthesis, rheological, rheo-optical and rheo-small angle neutron scattering (SANS) measurements, as well as simulation and theory. In particular, the role of particle contact friction versus enhanced lubrication friction will be elucidated along with implications for formulation.
Shear thickening fluids (STFs) are novel field-responsive materials that can be engineered to be useful nanocomposites for enhanced ballistic and impact protection, puncture resistant medical gloves, energy absorbing materials for mitigating impacts and concussions, as well as in systems for mitigating puncture, micrometeoroid, and orbital debris threats in space applications. The development of commercial applications of STFs will be discussed. The rheological investigations and micromechanical modeling serve as a framework for the rational design of STF-based materials to meet specific performance requirements not easily achieved with more conventional materials. I will illustrate some technological applications of STFs under commercial development, including use in astronaut protection with application in the Artemis Mission as well as the Mission to Mars, with the associated flight experiments on the International Space Station. Finally, I will present recent work on “planetopolymers” for in-situ resource utilization.
Bio: Norman J. Wagner is an Alison Professor of the University of Delaware and holds the distinguished Unidel Robert L. Pigford Chair in Chemical Engineering, with affiliated faculty appointments in Physics and Astronomy, Biomechanics and Movement Science, and Biomedical Engineering. He leads an interdisciplinary research team at the University of Delaware and is a co-founder and director of the
The Department of Chemical Engineering, part of the Herbert Wertheim College of Engineering, is one of the largest and highest ranked chemical engineering departments in the Southeast region and the premier chemical engineering department in the State of Florida. The department’s faculty and students conduct fundamental and applied research addressing important societal problems while advancing the discipline of chemical engineering in topics such as fluid mechanics, colloid and interface phenomena, biomolecular engineering, nanotechnology, advanced materials, catalysis, and surface science.
PREVIOUS DISTINGUISHED SPEAKERS IN THE FLUID MECHANICS ENDOWMENT SERIES
|2023||Norman J. Wagner||University of Delaware|
|2022||Jeffrey F. Morris||City College of New York|
|2019||Howard A. Stone||Princeton University|
|2017||Harry Swinney||University of Texas at Austin|
|2015||Grae Worster||University of Cambridge|