3D Printable Self-Sensing Magnetorheological Elastomer

Magnetorheological elastomers (MREs) are a category of smart materials composed of a magnetic powder dispersed in an elastomeric matrix. They are characterized by the ability to change their mechanical properties when an external magnetic field is applied, called magnetorheological (MR) effect. When a conductive filler is added to a magnetorheological elastomer, the resulting hybrid filler composite showcases both MR and piezoresistive effects. For such a reason, these composites are referred to as self-sensing magnetorheological elastomers. In this case, the synthesized self-sensing magnetorheological elastomers are based on styrene-based thermoplastic elastomers (TPS), carbonyl iron particles (CIP), and carbon black (CB). The hybrid filler concept using various coated CIP and constant CB content showed that above 25 vol.% CIP the resistivity increased rapidly. This work proposes the first case of a 3D printable self-sensing magnetorheological elastomer and cyclic mechanical compression and tensile mode analysis at high deformation (up to 20% and 10%, respectively). The results showcase a magnetoresistive change of up to 68% and a piezoresistive change of up to 42% and 98% in compression and tension, respectively. In addition, the magnetostriction of the self-sensing samples has been characterized to be 3.6% and 5.6% in the case of CIP 15 and 30 vol.%, respectively. Self-sensing magnetorheological elastomers (MREs) showcase resistive changes induced both by magnetic fields and mechanical loads, on top of magnetic-dependant stiffening. In this work, it is reported the first case of 3D printable self-sensing magnetorheological elastomers. The proposed materials are characterized both as a function of a varying magnetic field and mechanical cyclic load, both in compression and tension.image