Volume 77, Number 6, March 2007
Article Number 68004
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
Published online 01 March 2007
EPL, 77 (2007) 68004
DOI: 10.1209/0295-5075/77/68004

Magnetic-field-induced chain-like assembly structures of $\chem{Fe_{3}O_{4}}$ nanoparticles

W.-X. Fang, Z.-H. He, X.-Q. Xu, Z.-Q. Mao and H. Shen

State Key Laboratory of Optoelectronic Materials and Technologies, and School of Physics and Engineering, Sun Yat-sen University - Guangzhou, 510275, PRC

received 31 August 2006; accepted in final form 26 January 2007; published March 2007
published online 1 March 2007

By controlling the time to apply magnetic field to a ${\rm Fe}_{3}{\rm O}_{4}$ magnetic fluid with polymer acrylic resin and by evaporating the solvent, linear chain-like structures were obtained and fixed. Optical microscopy and transmission electronic microscopy (TEM) were used to observe the assembly structures of the fixed magnetic nanoparticles. We found that the chain-like structures with size even down to hundreds nanometers had smaller substructures. A picture of aggregation between linear chain-like substructures is proposed to understand the formation of the macrostructure in magnetic fluid induced by a magnetic field. Two basic aggregations, the coarsening and the connection of the substructures, were observed.

81.16.Dn - Self-assembly.
75.50.Mm - Magnetic liquids.
82.35.-x - Polymers: properties; reactions; polymerization.

© Europhysics Letters Association 2007