Efficient functionalization of magnetite nanoparticles with phosphonate using a one-step continuous hydrothermal...

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Magnetite nanoparticles (Fe3O4 NPs) are widely used but often suffer from poor colloidal stability.
• Surface functionalization is crucial for tailoring nanoparticle properties for specific applications.

Purpose of the Study:

• To synthesize phosphonate-functionalized Fe3O4 NPs using a one-step continuous hydrothermal process.
• To investigate the effect of 6-phosphonohexanoic acid (PHA) on NP characteristics and colloidal stability.
• To explore PHA grafting conformations and potential for further surface modification.

Main Methods:

• One-step continuous hydrothermal synthesis of Fe3O4 NPs.
• Surface modification with 6-phosphonohexanoic acid (PHA).
• Comprehensive characterization using TEM, XRD, DLS, ζ-potential, TGA, FTIR, XPS, and BET analysis.

Main Results:

• PHA functionalization reduced crystallite size and improved size distribution of Fe3O4 NPs.
• Significantly enhanced colloidal stability of PHA-modified NPs compared to bare Fe3O4 NPs.
• PHA grafted in multiple conformations (mononuclear monodendates, binuclear bidentates, lying-down complexes), with available carboxyl groups for further functionalization.

Conclusions:

• The continuous hydrothermal synthesis offers a promising route for stable and functionalized Fe3O4 NPs using phosphonate molecules.
• PHA modification effectively enhances NP stability and provides reactive sites for post-grafting, such as polyethylene glycol.
• This method holds potential for advanced nanomaterial development in various fields.