Morphology control of magnetic latex particles prepared from oil in water ferrofluid emulsion

Abstract

The use of magnetic latex particles as solid support in biomedical applications is favourable when homogeneous and well-defined core–shell polymer particles are used. Accordingly, this paper concerns with the synthesis of magnetic poly(styrene–divinylbenzene) latex particles using emulsion polymerization of styrene (St) and divinylbenzene (DVB) monomers in the presence of preformed oil in water organic ferrofluid emulsion droplets as seed. The key parameters which affect on formation and morphology of the prepared magnetic latexes were investigated, including type of magnetic emulsion, St/DVB monomers ratio, DVB amount, type of initiator and surfactant nature. In this study, two different magnetic emulsions were used, low and high octane content magnetic emulsions. The magnetic emulsions were stabilized using different types of surfactants including AP, Triton X 405 and SDS. In addition, four different initiators, including AIBN, V50, ACPA and KPS were examined. The morphology of the prepared magnetic latexes was investigated using transmission electron microscopy. In addition, particle size and size distribution, magnetic content and magnetic properties of the prepared magnetic latexes were also examined, using various techniques, e.g. dynamic light scattering, thermal gravimetric analysis and vibrating sample magnetometer, respectively. The results showed that the morphology type (Janus like, moon like and/or core–shell) of the prepared magnetic latex particles could be controlled depending mainly on the used formulation. In fact, the use of styrene monomer leads to anisotropic morphology. Whereas, the progressive use of DVB in presence of KPS intiator leads to a well-defined magnetic core and polymer shell structure.