Assembly of centimeter long silica coated FePt colloid crystals with tailored interstices by magnetic crystallization

Journal article

A bottom-up approach for the first synthesis of centimeter long magnetic colloidal crystals, which have adjustable internal interstices for potential use in magnetic gradient separation of chemical or biochemical entities was investigated. The large colloidal crystals were composed of three-dimensional regular arrays of superparamagnetic FePt nanoparticle encapsulated in a protective hydrophilic silica shell with controllable thickness. The powder sample was washed four times in pure ethanol to remove impurities. It was then placed in an ultrasonic bath for 1 hour with 100 mL of ethanol in a 150 mL beaker at 55°C for controlled crystallization. It was observed that the ability to assemble silica coated magnetic nanoparticles into high quality colloid crystals from the bottom-up construction approach through magnetic crystallization could open up a new avenue for preparing new porous magnetic crystals with high surface area for potential separation of chemicals or biochemicals of a wide range of interests.

Authors: Tsang, S; Yu, C; Tang, H; He, Y; Castelletto, V

• Journal: Chemistry of Materials
• Volume: 20
• Issue: 14
• Pages: 4554-4556
• Publication date: 2008-07-22
• DOI: 10.1021/cm801068j
• ISSN: 0897-4756
• Language: English