(185p) Facile Synthesis of Polymer/Magnetite Nanoparticle Composite

Polymer/magnetic particle composites have high magnetic sensitivity, and thus have wide applications in biomedical fields. One representative method of immobilizing a polymer on the surface of magnetic particles is to use a silane coupling agent. However, the application of the method is limited because of its complex and time-consuming processes, as well as the use of organic solvents. On the other hand, B. Tural et al. reported recently that if polymer containing a carboxyl group such as poly(methacrylic acid) was added to the coprecipitation solution during magnetite (Fe₃O₄) nanoparticle (MNP) synthesis, the polymer was immobilized on the magnetite surface immediately following particle generation. M. F. Tai et al. also reported the similar phenomena for the polymer containing a hydroxyl group such as polyethylene glycol. These methods are one-step process that does not require complex and time-consuming manipulation as well as organic solvent.

However, so far, to the best of our knowledge, there are no reports on what kind of polymer (or functional group) can be used for this type of one step synthesis of polymer/MNP composite. Therefore, in this study, we tried one-step synthesis of polymer/MNP composite by using different polymers which contains different functional group to clarify 1) what kind of functional groups can be applicable for one step polymer/MNP synthesis, and 2) the effect of the polymer difference on the immobilized polymer amount.

In the experiment, the synthesis of polyacrylic acid (PAAc) / MNP was carried out using the following procedure; first, PAAc, iron (II) sulfate heptahydrate and iron (III) chloride hexahydrate were dissolved in deionized water. Then, sodium hydroxide was dropped into the solution at room temperature to proceed MNP synthesis reaction. Polyacrylamide (PAAm), polyethylene glycol (PEG), polyethylene imine (PEI) and polyvinyl alcohol (PVA) immobilized on MNP were also synthesized using the same procedure just by changing PAAc to the corresponding polymers. The results of X­ray diffractometer (XRD) analysis showed that for all the polymers used in this study, formation of MNP was confirmed, and the fact indicated that the presence of the polymers did not affect on the synthesis of MNP. Thermogravimetric analysis (TGA) indicated that for all the polymers, polymer immobilized on MNP was successfully synthesized, and the amounts of the immobilized polymers were in the order of PEG < PEI < PAAm < PAAc.