Modeling magneto-mechanical behavior of Fe3O4 nanoparticle/polyamide nanocomposite membrane in an external magnetic field

The magnetic response of a polyamide nanocomposite membrane under applying a magnetic field has been modeled to evaluate elastic deformation order of magnitude. A PA-Fe3O4 nanocomposite membrane is considered to be modeled under influence of volume plane stress caused by a magnetic field. The modeling of the mechanical behavior of Fe3O4-PA nanocomposite membrane suggests that nanoparticle displacements within the nanocomposite, in the order of 200 nm under applying an external magnetic field, are greater than free volumes or porosities of the polyamide membrane. The membrane can be excited to mechanically vibrate by applying an alternating magnetic field lower than 0.1 T. As the results showed, there is an optimum nanoparticle size, %vol. loading and magnetic field strength to optimize such very small mechanical elastic deformations in the polymer, for controlling membrane functions. The perturbation and decreasing thickness of boundary layer and flow regime can be created by such vibrational elastic deformations on the membrane. It shows that the nanoparticle size has a more significant effect on membrane in-plane movement than their %vol. loading in the polyamide matrix. Decreasing loading of magnetic nanoparticles is very critical to fabricating high-performance membranes with appropriate and controllable magnetic and mechanical properties simultaneously. This phenomenon in vibrational mode might be exploited as a pathway to develop near surface mixing on the membrane, to hydrodynamically lower boundary layer thickness, control membrane separation behavior and enhance cleaning of the membranes, with inducing alternative magnetic fields.

Duke Scholars

Author Mark Wiesner Civil and Environmental Engineering