Core–Shell Magnetic Nanoparticles

López‐Ortega, Alberto

doi:10.3390/nano13050822

Cited by 1 publication

(1 citation statement)

References 4 publications

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“…Strict control over the temperature gradient in the reactor is essential to ensuring simultaneous nucleation and growth. Further, surface functionalization of IONPs for a core–shell structure with enhanced stability against coagulation typically necessitates the incorporation of organics [e.g., polymers, − biomolecules, ionic liquids (ILs)] through a post-treatment process. Therefore, the combination of MW synthesis with highly polar/conductive solvents such as ILs , has been of interest for achieving controlled particle nucleation and growth with in situ surface functionalization.…”

Section: Introductionmentioning

confidence: 99%

Tuning Surface, Phase, and Magnetization of Superparamagnetic Magnetite by Ionic Liquids: Single-Step Microwave-Assisted Synthesis

Cagli,

Klemm,

Ali

et al. 2024

ACS Appl. Mater. Interfaces

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Achieving colloidal and chemical stability in ferrofluids by surface modification requires multiple steps, including purification, ex situ modification steps, and operation at high temperatures. In this study, a single-step microwave-assisted methodology is developed for iron oxide nanoparticle (IONP) synthesis utilizing a series of imidazolium-based ionic liquids (ILs) with chloride, bis(trifluoromethylsulfonyl)imide, and pyrrolide anions as the reaction media, thus eliminating the use of volatile organics while enabling rapid synthesis at 80 °C as well as in situ surface functionalization. The characterized surface functionality, hydrodynamic particle size, magnetization, and colloidal stability of the IONPs demonstrate a strong dependence on the IL structure, ion coordination strength, reactivity, and hydrophilicity. The IONPs present primarily a magnetite (Fe 3 O 4 ) phase with superparamagnetism with the highest saturation magnetization at 81 and 73 emu/g at 10 and 300 K, respectively. Depending on the IL coating, magnetization and exchange anisotropy decrease by 20 and 2−3 emu/g (at 35 wt % IL), respectively, but still represent the highest magnetization achieved for coated IONPs by a coprecipitation method. Further, the surface-functionalized superparamagnetic magnetite nanoparticles show good dispersibility and colloidal stability in water and dimethyl sulfoxide at 0.1 mg/mL concentration over the examined 3 month period. This study reports on the intermolecular and chemical interactions between the particle surface and the ILs under synthetic conditions as they relate to the magnetic and thermal properties of the resulting IONPs that are well suited for a variety of applications, including separation and catalysis.

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