Publication: Grad Student Andy Clark and Professor of Physics Xuemei M. Cheng

"The Effect of Polymer Stiffness on Magnetization Reversal of Magnetorheological Elastomers"

Authors: Clark, Andy T.; Marchfield, David; Cao, Zheng; Dang, Tong; Tang, Nan; Gilbert, Dustin; Corbin, Elise A.; Buchanan, Kristen S.; Cheng, Xuemei M.

Source: APL Materials, Volume: 10, Issue: 4, DOI: 10.1063/5.0086761, April 2022

Type of Publication: Article

Abstract: Ultrasoft magnetorheological elastomers (MREs) offer convenient real-time magnetic field control of mechanical properties that provides a means to mimic mechanical cues and regulators of cells in vitro. Here, we systematically investigate the effect of polymer stiffness on magnetization reversal of MREs using a combination of magnetometry measurements and computational modeling. Poly-dimethylsiloxane-based MREs with Young’s moduli that range over two orders of magnitude were synthesized using commercial polymers Sylgard™ 527, Sylgard 184, and carbonyl iron powder. The magnetic hysteresis loops of the softer MREs exhibit a characteristic pinched loop shape with almost zero remanence and loop widening at intermediate fields that monotonically decreases with increasing polymer stiffness. A simple two-dipole model that incorporates magneto-mechanical coupling not only confirms that micrometer-scale particle motion along the applied magnetic field direction plays a defining role in the magnetic hysteresis of ultrasoft MREs but also reproduces the observed loop shapes and widening trends for MREs with varying polymer stiffnesses.

Professor Xuemei May Cheng is Professor of Physics and the Dean of Graduate Studies.