The effect of polymer stiffness on magnetization reversal of magnetorheological elastomers

• Main Authors: Buchanan, K.S (Author), Cao, Z. (Author), Cheng, X.M (Author), Clark, A.T (Author), Corbin, E.A (Author), Dang, T. (Author), Gilbert, D. (Author), Marchfield, D. (Author), Tang, N. (Author)
• Format: Article
• Language: English
• Published: American Institute of Physics Inc. 2022
• Subjects: Computational modelling; Elastic moduli; Elastomers; Hysteresis; In-vitro; Magnetic field controls; Magnetic fields; Magnetic materials; Magnetization - reversal; Magnetization reversal; Magnetometry measurements; Magnetorheological elastomers; Measurement model; Mechanical cues; Polydimethylsiloxane(PDMS); Real- time; Stiffness
• Online Access: View Fulltext in Publisher

 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. © 2022 Author(s).