Transforming single domain magnetic CoFe₂O₄ nanoparticles from hydrophobic to hydrophilic by novel mechanochemical ligand exchange

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• 作者：Sandeep Munjal ; Neeraj Khare
• 关键词：CoFe2O4 ; Ligand exchange ; Hydrophobic ; Magnetic nanoparticles ; Oil ; water emulsions ; Biomedical applications
• 刊名：Journal of Nanoparticle Research
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：19
• 期：1
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Nanotechnology; Inorganic Chemistry; Characterization and Evaluation of Materials; Physical Chemistry; Optics, Lasers, Photonics, Optical Devices;
• 出版者：Springer Netherlands
• ISSN：1572-896X
• 卷排序：19

文摘

Single-phase uniform-sized (~9 nm) cobalt ferrite (CFO) nanoparticles have been synthesized by hydrothermal synthesis using oleic acid as a surfactant. The as-synthesized oleic acid-coated CFO (OA-CFO) nanoparticles were well dispersible in nonpolar solvents but not dispersible in water. The OA-CFO nanoparticles have been successfully transformed to highly water-dispersible citric acid-coated CFO (CA-CFO) nanoparticles using a novel single-step ligand exchange process by mechanochemical milling, in which small chain citric acid molecules replace the original large chain oleic acid molecules available on CFO nanoparticles. The OA-CFO nanoparticle’s hexane solution and CA-CFO nanoparticle’s water solution remain stable even after 6 months and show no agglomeration and their dispersion stability was confirmed by zeta-potential measurements. The contact angle measurement shows that OA-CFO nanoparticles are hydrophobic whereas CA-CFO nanoparticles are superhydrophilic in nature. The potentiality of as-synthesized OA-CFO and mechanochemically transformed CA-CFO nanoparticles for the demulsification of highly stabilized water-in-oil and oil-in-water emulsions has been demonstrated.