Self-assembled core-shell Fe3O4@SiO2 nanoparticles from electrospun fibers

Abstract Fibers comprising the hydrophilic polymer polyvinylpyrrolidone K90, cetyltrimethylammonium bromide, tetraethyl orthosilicate and Fe 3 O 4 were fabricated using an electrospinning process. Silica coated magnetite (Fe 3 O 4 @SiO 2 ) core-shell nanoparticles (NPs) with high magnetic sensitivity were spontaneously formed through molecular self-assembly when the fibers were added to 80% aqueous ethanol (pH 9.0). The sizes of the Fe 3 O 4 @SiO 2 particles could be manipulated from 30 nm to 83 nm by varying the Fe 3 O 4 content in the fibers. A possible mechanism for the formation of templated Fe 3 O 4 @SiO 2 NPs is proposed. Since the nanoparticles have high magnetic sensitivity and controllable particle size ( via a facile and convenient strategy, they have much promise in a range of practical applications.