MSE PhD Prospectus Defense of Abigail Rendos

TITLE: THE ROLE OF ADDITIVES IN MAGNETORHEOLOGICAL FLUIDS

ABSTRACT: Functional nano or microparticles in solution can form stimuli-responsive smart fluids that exhibit rheological changes in the presence of a magnetic or electric field. The most commonly utilized type of particle-based smart fluid is the magnetorheological fluid (MRF) which contains ferromagnetic microparticles such that it reversibly switches from a liquid to a solid-like state. Along with the magnetic microparticles, additives such as surfactants, thixotropic agents, and nanoparticles are used to improve fluid stability or performance. Although various types of isotropic and anisotropic additives have shown the potential to improve both fluid stability and performance simultaneously, there are few systematic studies with direct comparisons or quantitative models to explain their effect on MRF behavior and performance. Here, we explore three classes of MRF in which the functional component, namely the ferromagnetic particles, are consistent but that vary in the type of additive. These additives were all selected as different approaches to explore the hypothesis that particle slip is the limiting factor in MRF performance. Specifically, we study 1) a shear thickening MRF 2) an MRF containing highly anisotropic 2D sheets and 3) an MRF containing DNA-linked magnetic chains. These studies have led to an improved understand of how additives can tune particle interactions and affect bulk rheological changes and were quantitatively explained using modeling that will enable better predictions of performance in the future. Further studies will investigate the effect of incorporating reversible chemical links between particles in order to control assembly in smart fluids and other fluid-particle systems.

COMMITTEE: ADVISOR, Professor Keith Brown, MSE, ME; Professor Tommaso Ranzani, MSE, ME; Professor Xi Ling, MSE, ECE; Professor Mark Grinstaff, MSE, BME

When 3:00 pm to 4:00 pm on Thursday, November 5, 2020
Location Zoom