Characteristic analysis of Fe₃O₄ nanoparticles modified by oleic acid and undecylenic acid

ABSTRACT

Carbonization of magnetic polymer microspheres is one of the methods for the preparation of magnetic carbon materials. Fe₃O₄ magnetic particle characteristics considerably influence the magnetic content and size distribution of magnetic polymer microspheres. The characteristics of Fe₃O₄ nanoparticles modified by oleic acid (OA) and undecylenic acid (UA) were analyzed by X-ray diffraction, Fourier transform infrared, scanning electron microscopy, dynamic laser light scattering, thermogravimetry/differential thermogravimetry, vibrating sample magnetometer, and water contact angle. Fe₃O₄ nanoparticles modified by OA and UA are nearly spherical and exhibit superparamagnetism. Fe₃O₄ particle size and saturation magnetization are slightly influenced by the OA and UA composition. OA and UA both are chemically adsorbed onto Fe₃O₄ as bidentate chelates. OA shows easier adsorption onto Fe₃O₄ than UA. OA groups have an expanded arrangement on OA@Fe₃O₄, whereas UA groups have a condensed arrangement on UA@Fe₃O₄. Particle lipophilicity decreases and particle clustering increases with decreasing OA content and increasing UA content on OA-UA@Fe₃O₄ nanoparticles.

KEYWORDS:

• Modified Fe₃O₄ nanoparticle
• Oleic acid
• Undecylenic acid

Acknowledgments

This work is financially supported by Natural Science Foundation of Zhejiang Province of China (Y12B060012), Public Projects of Zhejiang Province (2016c33031), Zhoushan science and technology project (2015C41017), and Dinghai District of Zhoushan science and technology project.