Nanocomposites and nanomaterials

Composites of magnetic nanoparticles and polymers for non-destructive flaw detection
Grabovaya N.V.1, Vasylenko I.V.1, Lytvynenko A.S.1, Kazakevych M.L.2, Pavlishchuk V.V.1, Kolotilov S.V.1
1 L.V.Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine. Prospect Nauki, 31, Kyiv-03028, Ukraine. 
E-mail: nvgrab@gmail.com
2 State Enterprise Koloran of L. V. Pysarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine. Prospect Nauki, 31, Kyiv-03028, Ukraine.

Non-destructive flaw detection is important field of magnetic nanoparticles application. The method is based on the nanoparticles arrangement in the magnetic field, distorted by the defect of the analyzed unit, which results in occurrence of the "image of the defect" on the surface. Such image forms upon application of the external magnetic field and often disappears when the magnet is removed. Development of methods for creation of stable images, which do not disappear upon magnetic field removal (stable replicas of defects), is actual task. 
The aim of this study was to develop composites of magnetic nanoparticles with organic monomers and polymers for non-destructive flaw detection and visualization and to reveal if such composites could form images that were stable without external magnetic fields. 
The composites of Fe3O4 (average size 15 nm) and CoFe2O4 (average size 8 nm) magnetic nanoparticles with a number of organic monomers and polymers were studied. Synthetic polymers (polystyrole, polyuretane, polyethyleneoxide, carboxymethylcellulose, polyvinyl acetate, polyvinyl alcohol), natural polymers (gelatin) as well as monomers (aniline, pyrrole) were used for composites creation.
It was found that composites of Fe3O4 or CoFe2O4 with polystyrole or polyvinyl alcohol had the best performance for creation of defects replicas due to high mobility of nanoparticles and quick solidification after coating of the surface, capacity to make high-quality flaw image and to preserve it for a long time. The influence of solvent nature, particles concentration and magnetic field intensity on flaws visualization was shown.
This work was carried out with the financial support of the Targeted Scientific Research Program of the National Academy of Science of Ukraine on Reliability and Duration of Materials, Structures, Equipment and Installations (Resource-2) (Project R 2.5)