Torque characterization of functional magnetic polymers using torque magnetometry

Magneto-Rheological Elastomers (MREs) are functional magnetic polymers filled with magnetic particles. MREs with fixed magnetic polarization within the particles, or H-MREs, develop a torque in response to an applied magnetic field. This ability leads to unique actuation properties which are critical for designs and applications of flexible actuators employing H-MREs. Thus, the primary goal of this paper is to characterize the relationship between torque generated and volume concentration of magnetic particles, an essential design parameter in H-MRE fabrication. To this end, a torque magnetometer based on a parallel plate capacitor was designed, and used to measure the torque response from H-MRE samples. The H-MRE samples were fabricated with varying percent volume of magnetic particles. The results from torque testing paralleled theoretical trends expected for the samples. An empirical correlation between volume content and maximum torque was found for samples above 10% volume composition and followed a linear trend. The equation governing the relationship was found from experimental results.