Fabrication of nearly monodispersed silica nanoparticles by using poly(1-vinyl-2-pyrrolidinone) and their application to the preparation of nanocomposites

Abstract

To fabricate dental nanocomposites containing finely dispersed silica nanoparticles, nearly monodispersed silica nanoparticles smaller than 25 nm were synthesized without forming any aggregates via a modified solgel process. Since silica nanoparticles synthesized by the Stober method formed aggregates when the particle size is smaller than 25 nm, the synthetic method was modified by changing the reaction temperature and adding poly(1-vinyl-2-pyrrolidinone) (PVP) to the reaction mixture. The size of the formed silica nanoparticles was reduced by increasing the reaction temperature or adding PVP. Furthermore, the formation of aggregates with primary silica nanoparticles smaller than 25 nm was prevented by increasing the amount of PVP added to the reaction mixture. To enhance the dispersion of the silica particles in an organic matrix, the synthesized silica nanoparticles were treated with 3-methacryloxypropyltrimethoxysilane (γ-MPS). A dental nanocomposite containing finely dispersed silica nanoparticles could be produced by using the surface-treated silica nanoparticles.

Changes in the moisture stability of CaS:Eu2+ phosphors with surface coating methods

“…10,20 Nearly monodisperse and spherical silica nanoparticles (5 nm) synthesized as described previously were used for phosphors coating. 10,22 The formation of the silica coating layer using five different methods was confirmed with EDS and FTIR. Figure 1 shows the EDS pattern of the uncoated phosphor and that of the phosphor coated with silica nanoparticles using coating method P 5 .…”

“…[19][20][21] The detailed synthetic procedure for silica nanoparticles was described previously. 10,22 Phosphor coating with silica nanoparticles was performed via five different methods, P 1 , P 2 , P 3 , P 4 , and P 5 . The details of each are described below.…”

“…P 2 : The proper amount of phosphor (10 g) was dispersed in methanol (1 L) solution containing TEOS (0.28 mol), water (20 mol), and NH 4 OH (2 mol), and then reacted at 80 o C for 1 h. Note that the aggregate with primary silica nanoparticles (5 nm) was formed at this reaction conditions when reaction mixture did not contain phosphors. 10,22 The resulting phosphor powders were also recovered with the same procedures as described for P 1 . P 3 : phosphor (10 g) was dispersed in a methanol (1 L) solution containing TEOS (0.28 mol), water (20 mol), and NH 4 OH (2 mol) and PVP (90 g) at 60 o C for 1 h. Note that monodispersed silica nanoparticles (5 nm) without aggregates formation was synthesized at this reaction conditions when reaction mixture did not contain phosphors.…”

Generation of open-ended, worm-like and graphene-like structures from layered spherical carbon materials

“…The presence of PVP (with a high molecular weight) on SiO 2 synthesis has been reported to cause a broad silica size distribution. 78 In this study, the volume of PVP used to make Au@SiO 2 A and Au@SiO 2 B (2 mL PVP) was less than that used to make Au@SiO 2 C (20 mL PVP) hence leading to modied SiO 2 -SiO 2 surface interactions during carbonization leading to different carbon deposits along the external SiO 2 surfaces.…”

Synthesis of highly monodisperse silica particles by addition of anionic surfactants

“…[2][3][4][5][6][7][8][9][10] Such big demand for silica particles has led many scientists to develop various synthetic routes such as hydrolysis of alkoxylsilanes, 11 microemulsion, 12,13 hydrolysis of elemental silicon, 14 ultrasonication 15 and seed-growth technique. 16,17 Among them, Stöber method seems to be the most effective and convenient route to synthesize monodisperse silica particles due to its availability of precursor and simple synthesis process.…”