Magnetoactive (MA) foam, with its tunable mechanical properties and magnetostriction, has the potential to be used for the development of soft sensor technology. However, researchers have found that its mechanical properties and magnetostriction are morphologically dependent, thereby limiting its capabilities for dexterous manipulation. Thus, in this work, MA foam was developed with additional capabilities for controlling its magnetostriction, normal force, storage modulus, shear stress and torque by manipulating the concentration of carbonyl iron particles (CIPs) and the magnetic field with regard to morphological changes. MA foams were prepared with three weight percentages of CIPs, namely, 35 wt.%, 55 wt.% and 75 wt.%, and three different modes, namely, zero shear, constant shear and various shears. The results showed that the MA foam with 75 wt.% of CIPs enhanced the normal force sensitivity and positive magnetostriction sensitivity by up to 97% and 85%, respectively. Moreover, the sensitivities of the storage modulus, torque and shear stress were 8.97 Pa/mT, 0.021 µN/mT, and 0.0096 Pa/mT, respectively. Meanwhile, the magnetic dipolar interaction between the CIPs was capable of changing the property of MA foam from a positive to a negative magnetostriction under various shear strains with a low loss of energy. Therefore, it is believed that this kind of highly sensitive MA foam can potentially be implemented in future soft sensor systems.

Magnetorheological (MR) foam, which is comprised of magnetic particles inside the matrix phase, is capable of changing its physical and rheological properties corresponding to the applied magnetic field. However, the performance of this material seems unsatisfactory due to the nonuniform distribution of magnetic particles throughout the composite area resulting in uneven magnetic properties. Since uniform magnetic properties are significant regarding MR foam, in situ fabrication using a polyvinyl chloride mould can be used to achieve the targetted improvement. MR foam was prepared with various amounts of carbonyl iron particles (CIPs), 0, 35, 45 and 55 wt%, and investigated at three different positions (top, middle and bottom parts) with a vibration sample magnetometer. The results showed that the hysteresis loop at all CIP concentrations of 35, 45 and 55 wt% exhibited superparamagnetic properties with magnetic saturation. The M _s of the top, middle and bottom positions were almost the same with a small standard deviation below 2 Am ² kg ^–1 . Moreover, it is observed that the effect of porosity results in the enhancement of the magnetic saturation and remanence values. These results reveal the promising uniform magnetic properties of MR foam, which can benefit the industry by helping produce a consistent MR foam.