Swelling and contraction of ferrogels based on polyacrylamide in a magnetic field

Structurization of ferrofluids in the absence of an external magnetic field

“…A comparison of our results to those obtained using a model [17] of the phase condensation in a ferrofluid consisting of chains leads to the conclusion that for mation of the network is preceded, at least, by the con densation of particles in a homogeneous liquidlike phase. This agrees with the results of laboratory exper iments and numerical simulations [6,[18][19][20]22], in which network clusters of magnetic particles have been observed.…”

“…Therefore, we can also be expect that the network formation in the system of magnetic particles takes place at lower and ϕ values than those necessary for the gas-liq uid transition. This conclusion agrees with observa tions of network structures in experiments [6,18,19] and numerical simulations [19,20,22].…”

“…However, in the absence of an external magnetic field, both experiments [6,18,19] and computer sim ulations [19][20][21][22] have shown that, when linear chains appear, an increase in the energy of magnetic interac tion between particles and their concentration leads to the formation of branched structures and networks. The self organization of dipole interacting particles into dense homogeneous globules without the prelim inary formation of chains has also been observed in computer simulations [23], but this result was obtained for the so called Stockmayer fluid, which consists of particles interacting like magnetic dipoles with a central Lennard Jones component.…”

“…The structures formed by mag netic particles in the matrix are fixed upon polymeriza tion. The macroscopic properties and behavior of a polymerized composition depend on the type of struc tures formed by particles in the matrix [18].…”

Magnetodeformation of ferrogels and ferroelastomers. Effect of microstructure of the particles’ spatial disposition

“…On the other hand magnetic particles in ferrogels and elastomers very often form linear chains and other heterogeneous structures [7,[21][22][23][24][25]. The way of generalization of the Lorentz approach to these situations is not obvious.…”