Spherical silica particles doped with iron oxide have been synthesized via base-catalyzed one-pot sol-gel process using tetraethoxysilane (TEOS) and iron(III) ethoxide (ITE) as co-precursors. In the modified Stöber process adopted, depending on the concentration of ITE in the starting composition, materials of various morphologies were observed under a scanning electron microscope and an atomic force microscope. The presence of ITE significantly affected the formation process of particulate silica; the spherical particles were formed accompanied by the copresence of irregular-shaped finer aggregates. The fraction of the aggregates with rough surfaces increased with an increase of the ITE content in the reaction mixture. Both the spherical particles and irregular-shaped aggregates contained iron hydroxide and they exhibited paramagnetic behavior. The chemical composition and physicochemical properties of the materials were determined using various complementary spectroscopic methods. Keywords Iron(III) ethoxide Á Sol-gel Á Microstructures Á Silica Electronic supplementary material The online version of this article (

No abstract

An effective way to obtain hollow hybrid silica-silicone nanocapsules of controlled diameter is presented. For that purpose a new precursor of silica-silicone material, tetra(triethoxysilylethyl) tetramethylcyclotetrasiloxane, was synthesized by hydrosilylation of vinyltriethoxysilane with tetramethylcyclotetrasiloxane. Mixture of dodecyltrimethylammonium bromide (DTAB) and sodium dodecylbenzenesulfonate (SDBS) in the cationic (the DTAB/SDBS system) rich region of the phase diagram was used to form the vesicular templates. The hybrid silica-silicone nanocapsules was obtained in base-catalyzed polymerization/polycondensation processes of the precursor inside of vesicle membrane. The shape and morphology of the silica-silicone nanocapsules was evaluated using transmission cryo-electron microscopy (cryo-TEM). Cryo-TEM reveals formation of discrete hollow shells of diameter consisted with the sizes of equilibrium vesicles used for templating.

No abstract

In the studies undoped HA and HA modified with 0.3; 0.6; 0.9; 1.8 wt % of Mg were prepared by the wet method. Introduction of magnesium into HA structure influenced its thermal stability as well as phase composition, sinterability, microstructure, flexural strength and chemical stability of the obtained calcium-phosphate ceramics. The presence of magnesium promoted the decomposition of HA to βTCP above 800°C. Beyond a certain limit (0.9 wt %), Mg ions caused formation of MgO in Mg-HA ceramics. Chemical stability of Mg modified HA below 0.9 wt % Mg under in vitro conditions was similar to that of the undoped hydroxyapatite. Biological studies showed that the number of cells cultured on the surface of HA samples with 1.8 wt % Mg additive, probably due to the MgO content, was lower than on the pure HA ceramics.