Magnetoresponsive smart nanocomposites with highly cross-linked polymer matrix

We propose a coarse-grained model, which is used for mesoscale simulation of nanocomposites based on a highly cross-linked polymer network with embedded magnetic nanoparticles (MNPs) whose structure is represented as a set of connected magnetic dipoles. All the simulations are carried out with reactive dissipative particle dynamics, taking into account the interaction of MNPs with an external magnetic field. To study the effect of the spatial organization of MNPs, the network formation from polymerizing monomers is simulated both in the field and without it. Under the influence of the field, the nanoparticles are organized into filamentous aggregates that induce the anisotropic structure of the polymer matrix and affect the network topology. The stress-strain curves demonstrate that the ordering of MNPs also causes anisotropy of mechanical properties and leads to an increase in Young's modulus for uniaxial tension along the long aggregate axis. When monomers polymerize in the presence of MNPs at zero applied field, the filler particles remain disordered and Young's modulus of such a composite can exhibit a weak linear decrease with increasing filler content. This behavior is well attributed to the reduction in the number of load-bearing chains in the simulation box. Additionally, the role of the polymer/MNP interface is studied. To this end, the corresponding interaction parameters are varied. It is found that the interface can provide an additional contribution to the tensile rigidity of composites.