engleski

The effect of polymers on the radiolytic synthesis of magnetic materials

Magnetic iron oxide nanoparticles (NPs) have applications as sensor, as contrast agents for MR imaging, in drug delivery and for hyperthermia cancer treatments. γ-irradiation is an attractive and ecologically friendly technique for the synthesis of magnetic nanoparticles at room temperature. It has an advantage of inducing electrons and other reducing species homogeneously through the sample. Unlike radiolytic synthesis of noble metal NPs, the radiolytic synthesis of iron oxide NPs is much less investigated. One of the reasons is a very complex iron oxide chemistry that produces numerous phases. Furthermore, magnetic NPs have a high tendency for agglomeration and due to these reasons various polymers are used that act as dispersants and stabilizers of magnetic NPs in suspensions as well as growth and surface modifiers. In this work we investigated the effect of 3 different polymers (DEAE-dextran, dextran sulfate and PEO), as well as the effect of absorbed dose of γ-irradiation on the synthesis of magnetic iron oxide nanoparticles. It was shown that the polymers completely stabilize the precursor particles before irradiation. The type of polymer, as well as the dose applied, had a strong influence on phase composition, morphology, and size of the formed nanoparticles, and in the case of PEO polymer, a completely different kind of product forms (hydrogel/Fe oxide nanocomposite material). In the case of DEAE dextran polymer, the phase composition was dominated by either magnetite or δ-FeOOH depending on the dose absorbed. In the case of dextran sulfate, a multiphasic system was obtained in all cases, with up to 4 different phases for each product obtained. Due to the nature of the PEO polymer, a simultaneous crosslinking of the polymer and the formation of single-phase iron oxide (magnetite in most cases) nanoparticles was observed.

gamma-irradiation ; amino dextran ; dextran sulfate ; poly(ethylene oxide) ; feroxyhyte ; magnetite ; magnetic hydrogel

nije evidentirano