Magneto-induced microstructure characterization of magnetorheological plastomers using impedance spectroscopy

An impedance spectroscopy (IS) method is employed to investigate the magneto-induced microstructure mechanism of magnetorheological plastomers (MRP). The IS of MRP with two typical particle distributions (isotropic and anisotropic) are compared and an equivalent circuit model is proposed to analyze the different impedance responses. It is found that the IS of anisotropic MRP is quite sensitive to the magnetic field and the electron diffusion effect will be restricted in the presence of a magnetic field. Furthermore, the conduction behavior of MRP in the presence of a magnetic field reveals the existence of elasticity in the polymer matrix. The influence of particle chain direction on the conductivity of anisotropic MRP with different particle contents is also investigated. Based on the experimental results, an equivalent method is developed to quantitatively characterize the anisotropy of MRP. With this method, the microstructure-dependent conduction mechanism of MRP can be presented more clearly. The rearrangement of particles induced by a magnetic field will change the thickness of the interface layer and the gaps between adjacent particles along the direction of electron transfer, and the conductivity of MRP will change accordingly.