Towards a theory of mechanical properties of ferrogels. Effect of chain-like aggregates

• The strain–stress dependence in ferrogels, in ferrogels with chains is nonlinear.
• In the presence of magnetic field the chains induce finite stress at zero strain.
• The magnetically induced stress non monotonic, with maximum, depends on the strain.

The paper deals with theoretical study of deformation of a ferrogel filled by magnetizable particles united in the chain-like aggregates. The sample is placed in a magnetic field parallel to the chains. Uniaxial elongation of the sample along the field is studied. Analysis shows that interaction of the particles in the chains and rupture of the chains by the elastic forces lead to non linear dependence of the macroscopical stress on the elongation strain. The theoretical results are in principle agreement with known experimental study of the ferrogels deformation.