On the Structure of Microaggregates in Magnetite Colloids

Self-assembly and rheology of dipolar colloids in simple shear studied using multi-particle collision dynamics

“…There are many other uncontrolled parameters, which can significantly influence the viscoelastic properties of the magnetic colloid. For one, the amount of free surfactant or primary agglomerates 121 remaining in the solution from the preparation stage is difficult to quantify, but it can significantly influence the measured viscosity.…”

Study of magnetisation behaviours for binary ionic ferrofluids

“…It needs to be pointed out that the microstructure of particular fluids is difficult to observe experimentally [19]. The electron microscope is a very useful tool for nanostructure observation, but, for the ferrofluids' structure investigation, only information about the size of separate particles can be obtained because the structure would undergo uncontrollable change while a sample was prepared for the examination [20]. For ferrofluids, especially binary ferrofluids, the microstructure as well as the relation between the microstructure and the physical behaviour should be further studied.…”

Microstructure and magnetic properties of magnetic fluids consisting of shifted dipole particles under the influence of an external magnetic field

“…The findings of these studies can be summarised as follows: (1) there are various mechanism with which the magnetic particle might respond to an external magnetic field, namely, Neél (the dipole rotate within the particle to coalign with an applied field, inherent to smaller particles, grows with particle size and depends on the particle material) and Brownian (the particle rotates as a whole to adjust its dipole moment to the direction of the field, a) weeber@icp.uni-stuttgart.de b) marco.klinkigt@me.com c) sofia.kantorovich@univie.ac.at d) holm@icp.uni-stuttgart.de inherent to bigger particles, grows with the volume of the particle and carrier viscosity); (2) the characteristic magnetic relaxation time of the ferrofluid depends on the magnetic particle size distribution; (3) there is no ferrofluid which exhibits an initial susceptibility lower than the one of the Langevin law; 36 (4) the stronger the inter-particle interaction is, the higher is the magnetic susceptibility of the system; (5) an external magnetic field strongly enhances the chain formation, and for higher fields even magnetic fluids with moderately interacting particles become strongly aggregated. All these features influence viscous, 7, 37-41 optical, 2-4, 42-44 diffusion, 6,45 scattering, [45][46][47][48][49][50][51][52] thermodynamic, 22 and acoustic 53 properties of ferrofluids. These systems are widely used in medicine, e.g., actuators [55][56][57] or sensors for the monitoring of anti-body reactions.…”