Preparation and characterization of water-based magnetorheological fluid using wormlike surfactant micelles

Magnetorheological fluids (MRFs) are smart materials whose rheological properties can be controlled via external magnetic field. One of the most important challenges of MRFs is their sedimentation problem. In this paper, worm-like micelles (WLMs) has been used to improve the properties of water based MRFs. Cetyltrimethyl ammonium bromide (CTAB) was used as a dispersant in the presence of KBr. The steady state and dynamic rheological measurements were performed to study the effect of CTAB concentration on the properties and the internal structure of the fluids. The static light scattering (SLS) and cryo-scanning electron microscope were done to study the structure of WLMs. The magnetorheological properties was studied under external magnetic field up to 76 kA/m. The stability of the suspensions was investigated by sedimentation test. The WLMs are formed in water at CTAB and KBr concentration of 0.2 M and 0.1 M respectively. It was found that MRFs with improved stability and yield stress can be obtained using WLMs in water.