Publication: Grad Student Andy Clark and ůůֱ²¥ 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.
ůůֱ²¥ Xuemei May Cheng is ůůֱ²¥ of Physics and the Dean of Graduate Studies.