Ferrofluids: properties, preparation and their transport engineering applications

Ferrofluids are colloidal systems consisting of ferromagnetic or ferrimagnetic nanoparticles dispersed in a carrier fluid, which results in their unique combination of magnetic and fluid-like qualities. Magnetic behaviour of these nanoparticles changes to superparamagnetism as a result of size reduction. These systems possess the ability to change their shape and behaviour under the influence of external magnetic field, making them ideal for a variety of applications. While initially developed for uses in aerospace engineering, ferrofluids are now applied in various industries including medicine, electronics, optics, transport and mechanical engineering. This paper presents an overview of the current state of ferrofluid research, focusing on the synthesis of magnetic nanoparticles, their qualities and subsequent applications in various technologies. Through this review, we aim to highlight the unique behaviour and qualities of ferrofluids and their potential for future innovations in the field.