Influence of magnetic-field-induced-alignment on the conductivity and electromagnetic shielding effectiveness of Ni/polyacrylate coatings

Ni/polyacrylate conductive coatings were prepared by utilizing magnetic field to control the alignment of nickel particles in acrylic emulsion. Their surface morphologies with and without the application of magnetic field were analyzed by SEM. The effect of magnetic field on the conductivity and shielding effectiveness of the coatings was studied. In combination with a dynamic model the influencing factors on the time of magnetic-field-induced-alignment (MFIA) was discussed. The results reveal that MFIA helps to generate a yarn-shaped microstructure in the coatings, which improves their conductivity. The percolation threshold of the resulting coatings decreases from 5,6% to 3.0% in volume fraction. Compared to the unaligned, the shielding effectiveness curve presents an even distribution after MFIA, and the electromagnetic shielding effectiveness is optimized. Alignment time can be controlled by changing the system viscosity and the applied magnetic intensity.