Superparamagnetic Silica Composite Nanospheres (SSCNs) with ultrahigh loading of iron oxide nanoparticles via an oil-in-DEG microemulsion route

Abstract

A method to prepare superparamagnetic silica composite nanospheres (SSCNs) by using iron oxide nanoparticles with ultrahigh loading through oil-in-DEG (diethylene glycol) microemulsion, was presented. The presented method involved hydrophobic SPIONs (superparamagnetic iron oxide nanoparticles) and tetraethylorthosilicate (TEOS) entrapped in oil droplets. It was observed that the hydrolysis and condensation of TEOS take place after ammonia diffuses through DEG. The use of hydrophobic SPIONs avoid the prior surface modification, while hydrolysis and condensation reaction take place only in presence of SPIONs. It was observed that the synthesized SSCNs produce higher saturation magnetization due to high loading density of SPIONs. This silica technique can be used for encapusalation of hydrophobic nanoparticles and quantum dots.