Silica matrices for embedding of magnetic nanoparticles

This paper presents a study regarding the formation of hybrid gels starting from tetraethyl orthosilicate (TEOS), polyvinyl alcohol (PVA) and 1,3-propanediol (PD) and their thermal evolution to mesoporous silica matrices. The possibility of obtaining homogenously dispersed cobalt ferrite inside the silica matrix starting from (TEOS–PVA–PD–Metal Nitrates) gels was also studied. The formation of the hybrid gels TEOS/PVA/PD with different compositions was studied by FT-IR spectrometry and thermal analysis, in order to evidence the interaction between the diol with the organic and the inorganic polymers. Both thermal analysis and FT-IR spectrometry have evidenced the formation of physical and chemical interaction between polyols and the siloxane network. Elemental mapping performed by SEM-EDX technique evidenced the formation of homogenous hybrids both in the presence of the absence of 1,3-propanediol. SEM images of the powders obtained by annealing the hybrid xerogels at 600 °C have evidenced the formation of mesoporous silica. By thermal treatment of the (TEOS–PVA–PD–Metal Nitrates) gels, 30%CoFe2O4/70%SiO2 (mass percent) nanocomposites uniformly dispersed in silica matrix with characteristic magnetic properties, have been successfully synthesized.