Abstract
Ferrofluids have attracted considerable interest from researchers and engineers due to their rich set of unique physical properties that are valuable for many industrial and biomedical applications. Many phenomena and features of ferrofluids’ behavior are determined by internal structural transformations in the ensembles of particles, which occur due to the magnetic interaction between the particles. An applied magnetic field induces formations, such as linear chains and bulk columns, that become elongated along the field. In turn, these structures dramatically change the rheological and other physical properties of these fluids. A deep and clear understanding of the main features and laws of the transformations is necessary for the understanding and explanation of the macroscopic properties and behavior of ferrofluids. In this paper, we present an overview of experimental and theoretical works on the internal transformations in these systems, as well as on the effect of the internal structures on the rheological effects in the fluids.
Highlights
Ferrofluids are nanodispersed suspensions of single-domain ferro- or ferrimagnetic particles in a carrier liquid
The cobalt-based ferrofluid with strongly interacting particles demonstrated a significant magnetoviscous effect. This agrees with the discussed chain formation model [68], where the appearance of the magnetoviscous effect is attributed to the strong interparticle interaction in the presence of a magnetic field
The first is related to the loss of the mechanical equilibrium of the domains, which are sloped under the shear stress relative to the direction of the externally applied magnetic field
Summary
Ferrofluids (magnetic fluids) are nanodispersed suspensions of single-domain ferro- or ferrimagnetic particles in a carrier liquid. Materials 2020, 13, 3956 threshold for the structuring of the particles depends on their magnetic moments, the thickness of the surface layers on the particles, the applied magnetic field, the temperature, and other parameters of the system. This is why it is impossible to determine some universal threshold concentration. The macroscopic physical properties of ferrofluids are determined by the internal structures and transition scenarios of the various morphologies of the particles’ spatial dispositions It enables controlling the properties and features of these systems’ behaviors over a wide range of magnitudes by using a magnetic field and other external influences. Discussions of the methods of ferrofluid synthesis, a basic introduction into the physics of these systems, and their practical applications can be found in books [1,2,3,4,5,6] and reviews [7,8,9,10,11,12,13,14,15]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call