プロセス・素材分野ショート講演3

[2K0701-13-02] Preparation of Polymer-Modified Magnetite Nanoparticles with Anisotropic Shapes and Controlled Sizes and the Particle Alignment under Magnetic Field

○Chen Shen¹, Masaki Matsubara², Mizuhoi Yabushita¹, Sachiko Maki¹, Atsushi Muramatsu¹, Kiyoshi Kanie¹ (1. Tohoku University, 2. Sendai College)

Keywords:Magnetite, Nanoparticles, Surface-initiated polymerization, Particle alignment

As a representative magnetic particle, magnetite (Fe₃O₄) nanoparticles have attracted considerable attention because Fe₃O₄ nanoparticles have been applied in many aspects. In fact, different applications require different magnetic properties, which are strongly influenced by the Fe₃O₄ nanoparticles’ sizes and shapes. Up to now, various shaped Fe₃O₄ nanoparticles, including nanocubes, nanorods, nanospheres and nanoplates, have been widely investigated. In particular, hexagonal Fe₃O₄ nanoplates with an anisotropic morphology have been expected to show marvelous physical and chemical properties. However, unmodified Fe₃O₄ nanoparticles aggregate easily due to magnetic attractive forces caused by the large surface energies, which seriously restricts the range of application. Therefore, it is necessary to combine Fe₃O₄ nanoparticles with other carriers to control the dispersion stability of nanoparticles.

On the other hand, poly(methyl methacrylate) (PMMA) has the advantages of high strength, good compatibility, dimensional stability and optical clarity. If functional PMMA chains could be introduced on the surface of Fe₃O₄ nanoparticles, the PMMA-modified Fe₃O₄ nanoparticles have been expected to exhibit remarkable properties, such as superparamagnetic, high miscibility, lyotropic liquid-crystalline property [1] and so on, due to the synergetic effect between them. One of the most effective ways to prepare polymer-modified nanoparticles is the surface-initiated atom transfer radical polymerization (SI-ATRP) [2]. SI-ATRP can control the molecular weight to decrease molecular-weight distribution and ensure the surface modification of high density.

In this report, hexagonal Fe₃O₄ nanoplates controlled in sizes and shapes were firstly synthesized. To introduce dispersibility towards organic solvents into Fe₃O₄ nanoplates, PMMA chains were grafted on the surface of Fe₃O₄ nanoplates via SI-ATRP. Alignment of PMMA-modified Fe₃O₄ nanoplates under magnetic field was also investigated.

References

[1] J. Yabuki, M. Matsubara, Y. Takanishi, A. Muramatsu, K. Kanie. Chem. Lett., 46, 303 (2016).

[2] K. Hayashida, H. Tanaka, O. Watanabe. Polymer., 50, 6228 (2009).