Magnificent Sea-Anemone-Like Magnetic Silica Capsules Reinforced with Carbon Nanotube

Marcos Sanlés-Sobrido, Verónica Salgueiriño-Maceira, Miguel A. Correa-Duarte, and Luis M. Liz-Marzán

Small, 2008, 4, 583–586

The fabrication of new nanostructures that resemble magnificent sea anemones aiming at increasing the rigidity and the availability surface of magnetic and reinforced CNTs-based hollow capsules was demonstrated. The construction of these complex nanostructures involves an initial layer-by-layer (LbL) sequential adsorption of polyelectrolytes and CNTs onto submicrometer-sized polystyrene (PS) spheres. Silica coating was performed by hydrolysis of tetraethyl orthosilicate in two separate steps. A first silica deposition at lower pH resulted in the formation of a thinner shell, whereas an outer shell was grown at a higher pH, allowing a tight control of the final thickness. The magnetic response of these hollow capsules was demonstrated by drying a drop of the dispersion on a Si wafer under an external magnetic field.