Characterization of highly stable water-based magnetorheological gel using OPTIGEL-WX as an additive: The study of magneto-induced rheological and viscoelastic properties

Abstract

In this work novel kinds of highly stable MR gels were prepared by suspending flake-shaped micron-sized carbonyl iron (CI) particles into water/OPTIGEL-WX suspension, OPTIGEL-WX is a promising additive that forms a gel-like structure with water. We found that surface tension decreases when the concentration of OPTIGEL-WX was raised, and the contact angle increased due to a stronger adhesive force at the liquid–air interface between the host liquid molecules and the CI particles. We examined magneto-induced rheological and viscoelastic properties using Anton-Paar (MCR-102) rheometer. The theoretical Bingham model was used to fit the experimental shear stress versus shear rate curves and observed static and dynamic yield stress values were substantially identical. Amplitude sweep showed that the linear viscoelastic region (LVE) was obtained approximately at 0.1% of shear strain. A crossover point, modulusG'&G", and yield stress were enhanced as the magnetic field was increased. Frequency sweep showed that the storage modulus shows an increasing trend with the increase of frequency at first, while at higher frequency range storage modulus shows a steady plateau area. Time-dependent shear flow and amplitude sweep tests revealed complete reversibility of rheological and viscoelastic properties of the MR gel with time after destroying the microstructures.