Mohapatra Sasmita, Pramanik Nabakumar, Ghosh Sudip K, Pramanik Panchanan
Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
J Nanosci Nanotechnol. 2006 Mar;6(3):823-9. doi: 10.1166/jnn.2006.117.
Nanosized magnetite (Fe3O4) particles showing superparamagnetism at room temperature have been prepared by controlled coprecipitation of Fe2+ and Fe3+ in presence of highly hydrophilic poly(vinylalcohol phosphate)(PVAP). The impact of polymer concentration on particle size, size distribution, colloidal stability, and magnetic property has been extensively studied. The aqueous suspension of magnetite, prepared using 1% PVAP solution is stable for four weeks at pH 5-8. X-ray diffractograms show the formation of nanocrystalline inverse spinel phase magnetite. Transmission Electron Microscopy confirmed well dispersed cubic magnetite particles of size of about 5.8 nm. Dynamic Light Scattering measurement shows narrow distribution of hydrodynamic size of particle aggregates. Infrared spectra of samples show strong Fe--O--P bond on the oxide surface. UV-visible studies show aqueous dispersion of magnetite formed by using 1% PVAP solution is stable at least for four weeks without any detoriation of particle size. Magnetization measurements at room temperature show superparamagnetic nature of polymer coated magnetite nanoparticles.
通过在高度亲水性的聚（乙烯醇磷酸酯）（PVAP）存在下对Fe2+和Fe3+进行受控共沉淀，制备了在室温下表现出超顺磁性的纳米级磁铁矿（Fe3O4）颗粒。已经广泛研究了聚合物浓度对颗粒尺寸、尺寸分布、胶体稳定性和磁性的影响。使用1% PVAP溶液制备的磁铁矿水悬浮液在pH 5-8下可稳定四周。X射线衍射图显示形成了纳米晶反尖晶石相磁铁矿。透射电子显微镜证实了尺寸约为5.8 nm的立方磁铁矿颗粒分散良好。动态光散射测量显示颗粒聚集体的流体动力学尺寸分布狭窄。样品的红外光谱显示氧化物表面有很强的Fe-O-P键。紫外-可见光谱研究表明，使用1% PVAP溶液形成的磁铁矿水分散液至少在四周内稳定，颗粒尺寸没有任何恶化。室温下的磁化测量显示了聚合物包覆的磁铁矿纳米颗粒的超顺磁性质。
