Electrorheological fluid and its preparation method

The invention relates to an electrorheological fluid material and its preparation method. The dispersed phase of the electrorheological fluid is a coated magnetic nano-composite particle compounded by flower-like ethylene glycol based iron or flower-like iron oxide nanoparticles and polyaniline nanoparticles growing thereon. The continuous phase is dimethyl silicone oil. The preparation process first employs a high temperature reflux method to prepare a flower-like ethylene glycol based iron precursor, which can directly undergo in-situ growth to obtain polyaniline so as to prepare the flower-like ethylene glycol based iron/polyaniline nanocomposite material; or the ethylene glycol based iron precursor can be calcined into iron oxide, which is then adopted as the substrate to undergo in-situ growth to obtain polyaniline nanoparticles, thereby preparing the monthly rose-like iron oxide/polyaniline nanocomposite material. The preparation process is simple, the raw materials are easily available, and the compone