<p> 25th Croatian meeting of chemists and chemical engineers, Poreč, 2017. Radiolytical synthesis of iron oxide nanoparticles in the presence of PEO, PVP, CTAB and DEAE-dextran Radiolitička sinteza nanočestica željezovih oksida u prisutnosti PEO-a, PVP-a, CTAB-a i DEAE-dekstrana </p><p>Tanja Jurkin,1 Marijan Gotić2, Goran Štefanić,2 Irina Pucić1 1Radiation Chemistry and Dosimetry Laboratory, Division of Materials Chemistry, Ruđer Bošković Institute, Bijenička 54, Zagreb, Croatia 2Center of Excellence for Advanced Materials and Sensing Devices, Research Unit New Functional Materials, Ruđer Bošković Institute, Bijenička 54, Zagreb, Croatia</p><p>E-mail: [email protected]</p><p>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 a powerful technique to synthesize NPs of controlled size and shape in solution, with advantage of inducing solvated electrons and radicals, able to reduce metal ions, homogeneously through the sample. The use of polymers or surfactants can influence the nanoparticle size, morphology, stability and dispersivity. The goal of this work was to study the influence of selected polymers/surfactant on the radiolytical synthesis of iron oxides. Iron(III) precursor solutions were γ-irradiated in the presence of poly(ethylene oxide) (PEO), polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB) and diethylaminoethyl-dextran hydrochloride (DEAE-dextran) [1]. γ-irradiation of iron(III) chloride/PEO aqueous solution produced rigid PEO hydrogels with embedded iron oxide NPs (Fig. 1a). Addition of 2-propanol increased the reducing power of γ-irradiation resulting in the formation of magnetite NPs (Fig. 1b); however 2-propanol reduced PEO crosslinking and thus less rigid hydrogels or suspensions were formed. PVP in Fe(III) solution produced magnetic suspension with a small amount of -FeOOH (feroxyhyte). γ-irradiation of Fe(III)/CTAB aq. solution favoured the formation of rod-like goethite NPs (Fig. 1c). Surprisingly, γ-irradiation of Fe(III)/DEAE-dextran aq. solution with 2-propanol produced almost pure -FeOOH magnetic nanodiscs (Fig. 1d). This result present the first report of γ- irradiation synthesis of -FeOOH and the first report of obtaining -FeOOH in nanodisc morphology [2].</p><p>1,5x106</p><p>1,5x106</p><p>1,5x106</p><p>1,5x106 s t n</p><p> u 6</p><p> o 1,5x10 C 1,5x106</p><p>1,5x106</p><p>1,5x106</p><p>-10 -5 0 5 10 Velocity / mm s-1</p><p> a) b) 100 nm c) 100 nm d) 100 nm Figure 1: SEM images, photos and Mössbauer spectrum of different iron oxide nanoparticles and composite gel prepared by γ-irradiation of Fe3+ aqueous solutions in the presence of PEO (a, b), CTAB (c) and DEAE-dextran (d). Nanocomposite gel (a); magnetite NPs (b); rod-like goethite NPs (c); -FeOOH magnetic nanodiscs (d).</p><p>References [1] T. Jurkin, M. Gotić, G. Štefanić and I. Pucić, Radiat. Phys. Chem. 124 (2016) 75-83. [2] T. Jurkin, G. Štefanić, G. Dražić and M. Gotić, Mater. Lett. 173 (2016) 55-59. </p>