Effects of particle pre-orientation via application of magentic field on the piezoresistivity of magnetorheological elastomer

To investigate the piezoresistivity mechanism and the influence factors of magneto-rheological elastomer(MRE), the conduction models and resistance expressions of isotropic and anisotropic MREs were established respectively based on their structural characteristics and the field emission theory. Further, the effects of Ni filler concentration in silicone rubber and applied voltage on the resistance were analyzed. Experiments were carried out to study the piezoresistive properties of the two MREs. MRE samples with isotropic (prepared without magnetic field) and anisotropic (pre-orientated with a magnetic field) distributions of Ni powders were prepared, respectively. The two conduction models were verified through comparison of the mapping relationships between the experimental pressure and the logarithmic resistance data. In comparison with the high impedance and low resistance range of the isotropic MRE, the anisotropic MRE changes from 10⁶ Ω under 0 kPa to 10 Ω under 6 kPa, which presents a better feasibility in tactile sensing applications.