The role of additives in enhancing the rheological properties of magnetorheological solids - a review

Abstract

During the last two decades, magnetorheological (MR) materials have attracted a significant amount of attention because of their tremendous potential for engineering applications. This review focuses on the role of various additives in enhancing the magnetic field-dependent rheological characteristics of solid and thixotropic matrice-based MR materials (hereafter referred to as MR solids). Typically, MR solids consist of solid or semi-solid matrices filled with magnetizable particles. However, additives need to be used to improve their performance such as the MR effect. This parameter is typically determined by the field-dependent dynamic modulus. Three different groups of additives would be introduced in the review namely plasticizers, carbon- and chromium-based additives. Compared to particles in the common matrix without a softener, those in matrices with additives which act as matrix softeners will be aligned easier during curing. In fact, the interfaces bonding between matrix-particles would be improved that subsequently enhanced the magnetically induced viscoelastic properties of MRE. In this review, the influences of several additives on the MR effect of various MR solids including MR elastomers, MR greases, and MR gels, which are recognized as efficient smart materials for practical applications in various engineering fields, are surveyed and discussed.