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The influence exerted by addition of [3-(methacryloyloxy) propyl]trimethoxysilane (MPTMOS) on the porosity and size of silica particles synthesized in a water-ethanol-ammonia-tetraethoxysilane (TEOS) mixture by the Stober-Fink-Bohn method with the subsequent calcination in oxygen at 400 °C was studied. A set of particles was synthesized at the same relative amounts of the starting reagents and at the same temperature of the reaction mixture. It was shown that as the amount of MPTMOS in the TEOS + MPTMOS precursor is raised from 0 to 12.5 mol%, the final size of the resulting SiO2 particles decreases from ∼400 to ∼10 nm, which is presumably due to the increase in the number of nucleation centers by several orders of magnitude. It was found that the particles have micropores, which are presumably formed upon removal of methacryloyloxypropyl groups by calcination. As the MPTMOS:TEOS molar ratio is raised, the micropore volume and the apparent specific surface area of the particles first grow and reach values of 0.15 сm3 g−1 (350 m2 g−1), and then decrease to 0.05 сm3 g−1 (100 m2 g−1) because the particle size (∼10 nm) becomes comparable with the pore size (1–2 nm). Upon addition of one more porogen, cetyltrimethylammonium bromide (CTAB), to the reaction mixture, the micropore volume and the apparent specific surface area of the particles substantially increase to become 0.25 cm3 g−1 and 600 m2 g−1, correspondingly, and the particle size rises to 50 nm. Probably, mesopores formed upon oxidation of CTAB micelles and micropores are mutually connected and form a common network within the particles. The total pore volume and the specific surface area of the particles determined by BET reach values of 1.05 cm3 g−1 and 1200 m2 g−1, respectively.

The method of obtaining nanoclusters α-Fe2O3 in the pores of monodisperse spherical particles of mesoporous silica (mSiO2) by a single impregnation of the pores with a melt of crystalline hydrate of ferric nitrate and its subsequent thermal destruction has been proposed. Fe3O4 nanoclusters are synthesized from α-Fe2O3 in the pores by reducing in thermodynamically equilibrium conditions. Then particles containing Fe3O4 were annealed in oxygen for the conversion of Fe3O4 back to α-Fe2O3. In the result, the particles with the structure of the core-shell mSiO2/Fe3O4@mSiO2/α-Fe2O3 are obtained. The composition and structure of synthesized materials as well as the field dependence of the magnetic moment on the magnetic field strength have been investigated.

Submicrometer spherical micro-mesoporous SiO 2 particles have been synthesized with a Brunauer–Emmett–Teller specific surface area of up to 1600 m 2 g −1 , comparable with that of nanoporous carbon materials. The particles are constituted by densely packed SiO 2 channels, similarly to materials of the MCM-41 type. The particles have two pore subsystems: monodisperse cylindrical mesopores with controllably varied average diameter (2.5–3.5 nm) and micropores supposedly situated within the walls of the SiO 2 channels and between their outer surfaces. The particles with combined micro-mesoporous structure are obtained by hydrolysis of a mixture of tetraethoxysilane (TEOS) and [3-(methacryloyloxy)propyl]trimethoxysilane (MPTMOS) with molar ratio 5:1 in an alcoholic–aqueous–ammonia medium containing surfactant (cetyltrimethylammonium bromide + 1,3,5-trimethylbenzene). Negatively charged products of hydrolysis of silica precursors (TEOS and MPTMOS) are condensed near the positively charged amino groups situated on the surface of the cylindrical micelles of surfactant forming SiO 2 layer containing hydrophilic methacryloyloxypropyl (MP) groups in the interior. Due to the Van der Waals forces, these micelles coated with a SiO 2 layer are organized into surfactant–silica clusters forming identical spherical aggregates. Removing of surfactant micelles and MP groups leads to formation of mesopores and micropores consequently.

In this research, a novel IMAC sorbent with high specificity for chlorine-containing compounds was developed. Ni-functionalized monodisperse spherical mesoporous silica particles of 500±25nm diameter were synthesized and their metal affinity properties were studied with the use of diclofenac as the model substance. The particles were aggregatively stable in the pH range of 3-12. The sorbent demonstrated a high adsorption capacity (0.60±0.06μg of DCF per 1mg of the sorbent) and high adsorption/desorption rate (20 and 5min was enough for the sorbent saturation and desorption of DCF, correspondingly). A mixture of eluents with addition of PFOS providing the almost complete recovery (98%) of diclofenac was first proposed. The monodispersity and the high sedimentation and aggregative stability of the particles provide the formation of a stable hydrosol even under ultrasound treatment which makes the mSiO2/Ni particles suitable for batch chromatography.

A facile template synthesis has been developed to obtain monodisperse spherical mesoporous nanocomposite mSiO2/C-dots/Eu3+ particles of submicron size exhibiting bright broadband luminescence in the visible spectral range. The use of europium ions made it possible to increase the integrated emission intensity of the nanocomposite particles in the reddish-orange region. The particles have a specific surface area of 540 m2/g, pore volume of 0.35 cm3/g, and average pore diameter of 2.7 nm. The obtained particles are promising for application in nanomedicine as nanocontainers simultaneously serving as biomarkers.

Core–shell nanoparticles with diameters in the range 100–500 nm have been synthesized as monodisperse spherical mesoporous (pore diameter 3 nm) silica particles with size deviation of less than 4 %, filled with gadolinium and europium oxides and coated with a mesoporous silica shell. It is shown that the melt technique developed for filling with gadolinium and europium oxides provides a nearly maximum filling of mesopores in a single-run impregnation, with gadolinium and europium uniformly distributed within the particles and forming no bulk oxides on their surface. The coating with a shell does not impair the monodispersity and causes no coagulation. The coating technique enables controlled variation of the shell thickness within the range 5–100 % relative to the core diameter. The thus produced nanoparticles are easily dispersed in water, have large specific surface area (300 m2 g−1) and pore volume (0.3 cm3 g−1), and are bright solid phosphor with superior stability in aqueous media. The core–shell structured particles can be potentially used for cancer treatment as a therapeutic agent (gadolinium neutron-capture therapy and drug delivery system) and, simultaneously, as a multimodal diagnostic tool (fluorescence and magnetic resonance imaging), thereby serving as a multifunctional theranostic agent.

We use the picosecond acoustic pump-probe technique to study the elastic properties of monodispersemesoporous silica spheres filled with nickel and deposited in the form of opal-like films on silica substrates. The picosecond pump-probe optical transmission signal shows harmonic oscillations corresponding to the lower energy radial Lamb mode in the vibrational spectrum of the spheres. These oscillations, with a frequency of several gigahertz last for several nanoseconds in the spheres with diameter 1050 nm, showing high homogeneity of the sphere parameters. By analysis of the oscillation spectrum of films with different sphere diameter and nickel content we obtain the elastic moduli of the mesoporous silica spheres., 7 pages, 3 figures, 1 table

The opal-GaN-ZnS:Mn composites with various GaN:ZnS ratios were synthesized by chemical bath deposition. These materials are perfect three-dimensional photonic crystals, which produce effective photo- and electroluminescence at room temperature. The emission spectra are considerably modified by the photonic crystal structure to become anisotropic in accordance with the photonic band gap angular dispersion.

Site-selective and fluorescence line narrowing (FLN) laser spectroscopy was used to study the structure of Eu3+-doped Gd2O3-based material embedded in the mesopores of submicron-sized monodisperse spherical amorphous SiO2 particles that are of interest for biomedical applications. The phase composition of the material in the pores was determined and the transformations that occur under heat treatment were studied. The room-temperature homogeneous linewidth of 5D0 − 7F0 transition of Eu3+ ions in different Gd2O3/SiO2 phases was measured with FLN technique. The radiative lifetime of the 5D0 excited state of Eu3+ ions was measured with time-resolved fluorescence technique; the local field effects on radiative transitions in the composite material are discussed.