We explored the effect of applying magnetic fields on the development of both the electrified jet and the whipping instability during electrospinning of polymer solutions loaded with magnetic nanoparticles. A preliminary study on the effect that sonication and particle addition have on the rheological properties of polymer solutions is also presented.  Magnetic nanoparticles of magnetite (Fe3O4) and cobalt ferrite (CoFe2O4) where suspended in poly(ethylene oxide) (PEO) solutions. These particles where dispersed by either sonication or mechanical stirring. Steady state and oscillatory rheological measurements were performed on the different solutions. Chain scission caused by sonication is reported. Additionally, the effect that particle addition has on the entanglement structure of polymer molecules is reported. High speed imaging was employed to study the behavior of the electrified jet at the exit of the capillary. These images showed that both solution viscosity and applied electric are the key parameters on determining the onset of the whipping instability. Scanning Electron Microscopy (SEM) was used to examine the final fiber morphology and size.  High speed imaging was employed to study the effect of the static magnetic field on the electrospinning process. An increase in the electric field required for the electrified jet to initiate was observed when a magnetic field was applied.  This extra energy requirement was attributed to a magnetic force created between the magnet and the polymer/nanoparticles solution which must be overcome by the electric field. Furthermore, at low electric fields an increase in the onset of the whipping instability is reported. This behavior was related to the magnetoviscous effect, which is known to cause an increase in a magnetic fluid's viscosity.

Manipulation of electrified jets of polymer solutions loaded with magnetic nanoparticles using magnetic fields

241st National Meeting (2011)

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