title: Controlling the size of magnetic nanoparticles using pluronic block copolymer surfactants.
abstract: We have successfully controlled the size of magnetic nanoparticles by adjusting the surfactant/solvent ratio. Gamma-Fe(2)O(3) nanoparticles of 5.6 and 12.7, and Fe(0) nanoparticles of 22.3 nm in diameter were prepared, all having spherical shape and uniform size as confirmed by TEM. Mössbauer spectra confirmed Fe(3+) for the 5.6 and 12.7 nm particles and Fe(3+) and Fe(0) for 22.3 nm particles, in good agreement with synchrotron XRD patterns. Both room temperature and 5 K H-M measurements show that 22.3 nm particles have much higher magnetization than their oxide counterparts, in agreement with their being Fe(0). T-M measurements show superparamagnetism for 5.6 and 12.7 nm particles and ferromagnetism for 22.3 nm particles.
authors.forename: Jr-iuan
authors.initials: JI
authors.lastname: Lai
authors.forename: Kurikka V P M
authors.initials: KV
authors.lastname: Shafi
authors.forename: Abraham
authors.initials: A
authors.lastname: Ulman
authors.forename: Katja
authors.initials: K
authors.lastname: Loos
authors.forename: Yongjae
authors.initials: Y
authors.lastname: Lee
authors.forename: Thomas
authors.initials: T
authors.lastname: Vogt
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Lee
authors.forename: N P
authors.initials: NP
authors.lastname: Ong
authors.forename: Claude
authors.initials: C
authors.lastname: Estournès
mesh_terms: D005290:Ferric Compounds / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D008280:Magnetics; D046529:Microscopy, Electron, Transmission / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D011108:Polymers; D013501:Surface-Active Agents; C000499:ferric oxide; D007501:Iron