*3.1. Morphological Property*

In the MRE, the suspension of magnetic particles and the adhesion between the CI particles and the medium are very important to the properties of the MRE. Morphology of the isotropic and anisotropic MREs is observed through scanning electron microscope (SEM) [97,104]. To observe the morphology of the MRE, the sample is soaked in liquid nitrogen and cut perpendicularly. Through this morphology observation, the adhesion between magnetic particles and matrix and dispersion state of magnetic particles can be observed. Figure 3a is an isotropic MRE prepared without a magnetic field and Figure 3b is SEM image mapped by EDX of anisotropic MRE prepared under magnetic field conditions during curing. Figure 3a shows randomly dispersed carbonyl iron particles in SR. Figure 3b is SEM images of anisotropic MRE sample. Unlike Figure 3a image, the CI particles are aligned in the elastomeric medium, and this confirms that it is anisotropic MREs. These morphological characteristics are deeply associated to the mechanical and MR characteristics of MREs and are important factors for applications.

**Figure 3.** SEM images of the pure CI particles based isotropic MRE (**a**) [97] and anisotropic (**b**) MRE [104].
