Amphiphilic Block Copolymers Directed Interface Coassembly to Construct Multifunctional Microspheres with Magnetic...

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Core-shell magnetic porous microspheres are crucial for drug delivery, catalysis, and bioseparation.
• Synthesizing these microspheres with uniform, large mesopores (>10 nm) for immobilizing large molecules is challenging.

Purpose of the Study:

• To develop a facile and general strategy for synthesizing core-shell magnetic mesoporous microspheres with tunable shell compositions and large mesopores.
• To evaluate the performance of the synthesized microspheres in pesticide removal and as nanocatalysts.

Main Methods:

• An amphiphilic block copolymer (polystyrene-block-poly (4-vinylpyridine)) was used as a structure-directing agent for interfacial coassembly.
• Shell precursors like aluminum acetylacetonate, zirconium acetylacetonate, and tetraethyl orthosilicate were employed to create aluminosilicate, silica, and zirconia-silica shells.
• Characterization of the microspheres included analysis of pore size, surface area, and acid site density.

Main Results:

• Core-shell magnetic mesoporous aluminosilicate (CS-MMAS) microspheres with perpendicular mesopores (20-32 nm), high surface area (244.7 m² g⁻¹), and abundant acid sites (0.44 mmol g⁻¹) were successfully synthesized.
• CS-MMAS microspheres demonstrated superior performance in removing fenthion, a type of organophosphorus pesticide, with fast adsorption and high capacity.
• CS-MMAS microspheres loaded with gold nanoparticles served as an active heterogeneous nanocatalyst for N-alkylation reactions, achieving over 90% selectivity and yield with good magnetic recyclability.

Conclusions:

• The developed amphiphilic block copolymer-directed strategy offers a versatile route to synthesize core-shell magnetic mesoporous microspheres with large pores.
• The CS-MMAS microspheres show significant potential for environmental remediation (pesticide removal) and advanced catalytic applications.