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Nanocasting of Superparamagnetic Iron Oxide Films with Ordered Mesoporosity
Author(s) -
Kraffert Katrin,
Kabelitz Anke,
Siemensmeyer Konrad,
Schmack Roman,
Bernsmeier Denis,
Emmerling Franziska,
Kraehnert Ralph
Publication year - 2018
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201700960
Subject(s) - maghemite , superparamagnetism , materials science , magnetite , mesoporous material , chemical engineering , iron oxide , nanotechnology , magnetization , organic chemistry , metallurgy , chemistry , physics , quantum mechanics , magnetic field , engineering , catalysis
Abstract Maghemite and magnetite show superparamagnetic behavior when synthesized in a nanostructured form. The material's inducible magnetization enables applications ranging from contrast enhancing agents for magnetic resonance imaging to drug delivery systems, magnetic hyperthermia, and separation. Superparamagnetic iron oxides with templated porosity have been synthesized so far only in the form of hard‐templated powders, where silicon retained from the template severely degrades the material's magnetic properties. Here, for the first time, the synthesis of superparamagnetic iron oxides with soft‐templated mesopore structure is reported. The synthesis of nanostructured maghemite and magnetite films succeeds using micelles of amphiphilic block‐copolymers as templates. A thermal treatment of the initially formed mesoporous ferrihydrite in nitrogen produces maghemite, which can be partly reduced to magnetite via thermal treatment in hydrogen while retaining the templated mesopore structure. The resulting materials feature a unique combination of high surface area, controlled pore diameter, and tunable magnetic properties.