A facile heteroaggregate-template route to hollow magnetic mesoporous spheres with tunable shell structures

Abstract

Uniform hollow magnetic mesoporous silica spheres (HMMS), with Fe₃O₄ nanoparticles embedded in the mesoporous shell, were successfully prepared by using carboxylic polystyrene latex and Fe₃O₄ heteroaggregates as the hard template together with a coating of tetraethoxysilane (TEOS) and n-octadecyltrimethoxysilane (C₁₈TMS) mixture. The HMMS outer diameter is about 370 nm and the thickness of the mesoporous shells is around 20 nm. Both the morphology and the thickness of the shell can be easily tuned by tailoring the amount of PS latex and the concentration of ammonia. Meanwhile, the magnetic properties can be slightly changed by adjusting the weight ratios of PS/Fe₃O₄. In addition, the HMMS demonstrates high drug storage capacity and sustained release properties, demonstrating that this kind of HMMS could be used as a promising material in drug delivery systems.