Properties of calcium-phosphate materials obtained by sol-gel method: effect of MgO concentration

Abstract A calcium-phosphate system was obtained by sol-gel method from 0.4 M solutions based on ethyl alcohol, tetraethoxysilane, phosphoric acid, calcium nitrate, and magnesium nitrate. Two compositions with different content of CaO and MgO were prepared. After the maturation of solutions they followed by heat treatment at 60°C for 30 minutes and at 600°C and 800°C for 1 h. Solution with 20 wt.% MgO is suitable for film production up to seven days, while 5 wt.% MgO is available for creation of films only on the second day of its preparation. Thin films were obtained on the second day by spin-coating with a centrifuge speed of 3000 rev/min, followed by heat treatment at 60°C for 20 minutes and at 800°C for 1 h. The formation of crystalline phases in synthesized materials occurs at 800°C. An increase in the content of magnesium oxide in the system helps to accelerate the growth of particles on the surface of the samples when immersed in a simulation body fluid

Properties of calcium phosphate thin film biomaterials with the addition of titanium oxide

Thin films were synthesized by sol-gel method from alcohol film forming solutions (FFS) based on tetraethoxysilane, phosphoric acid, calcium chloride. Concentration of tetrabutoxytitanium was 0.4 and 0.3 M. Thin films were produced on substrates of single crystal silicon (model substrate) by spin-coating with a centrifuge speed of 3000 rev/min, followed by heat treatment at 60 °C for 20 minutes and at 600 °C for 1 h. During the experiment it was found that film with uniform surface may be got on the fifth day after preparation of the solution with a concentration of Ti4+ 0.3 M. For homogeneous material requires heat treatment at 800 °C. The highest bioactivity was observed in the films based on film-forming solution with a concentration of Ti4+ 0.3 M

Synthesis of TiO2−SiO2−Ag/fiberglass with antibacterial properties and its application for air cleaning

The TiO2−SiO2−Ag/fiberglass with antibacterial properties under UV light irradiation was synthesized. The effects of compositions of TiO2−SiO2−Ag/fiberglass, optical, and textural characteristics on the antibacterial activity were studied. The TiO2−SiO2−Ag film was coated on the surface of fiberglass carrier filaments. The temperature effect on the formation of the TiO2−SiO2−Ag film was established by thermal analysis, and the temperature treatment mode was selected as 300 °C for 30 min, 400 °C for 30 min, 500 °C for 30 min, and 600 °C for 30 min. The influence of silicon oxide and silver additives on the antibacterial properties of TiO2−SiO2−Ag films was established. Increasing the treatment temperature of the materials up to 600 °C increased the thermal stability of the titanium dioxide anatase phase, while the values of optical characteristics decreased: the film thickness decreased to 23.92 ± 1.24 nm, the refractive index decreased to 2.154 ± 0.002, the energy of the band gap width decreased to 2.8 ± 0.5, and the light absorption shifted to the visible-light regime, which is important for photocatalytic reactions. The results showed that the use of TiO2−SiO2−Ag/fiberglass allows significant decrease in the value of CFU microbial cells to 125 CFU m−3

The low-temperature sol-gel synthesis of metal-oxide films on polymer substrates and the determination of their optical and dielectric properties

Photoactive, optically transparent heterostructures from silver nanowires and titanium dioxide were obtained by the sol-gel method on the surface of a polyethylene terephthalate film. The characteristics of optical transmission on the wavelength and those of dielectric permittivity, conductivity and dissipation on frequency in the range of 25–1,000,000 Hz were investigated

Sol-gel preparation and properties of thin-film biomaterials for the SiO2–P2O5–CaO–ZnO system

Thin films for the SiO2–P2O5–CaO–ZnO system were synthesized by the sol-gel method. The compositions and technology for producing thin-film materials on a silicon substrate (model substrate) were developed. The structure of the films was investigated by means of infrared spectroscopy and x-ray phase analysis. It was established that the concentration and contents of the components in the system influence the properties of thin-film materials. The obtained materials are biologically highly active. The composition for obtaining thin-film material with a higher biological activity was determined

Effect of TiO2 content on the synthesis and physicochemical properties of thin-film calcium phosphate materials

To produce materials based on the P2O5–CaO–TiO2 system, we have prepared film-forming solutions of four compositions, containing 70, 75, 85, and 95 wt % titanium(IV) oxide. The suitability of the filmforming solutions for film growth has been shown to be limited to viscosity values in the range from 3.4 to 3.7 mm2/s. At 70 and 75 wt % titanium(IV) oxide, a CaTiO3 (perovskite) phase has been identified in the P2O5–CaO–TiO2 system. The most uniform deposition of particles, with a large number of open pores after immersion in simulated body fluid (SBF), has been observed at 70 and 75 wt % titanium(IV) oxide. These compositions are thus the best suited for practical application

Synthesis and biological properties of thin-film materials on the basis of SiO2-P2O5-CaO-Na2 system

Thin films for the SiO2–P2O5–CaO–Na2O system are synthesized using sol-gel method. Content of the oxides in the system is 52-18-20-10 wt.% correspondingly. Thin films were produced from film-forming solutions on the single-crystal silicon substrates (model substrate) by extraction at a velocity of 5 mm/s following by heat treatment at a temperature of 60-80 °С for 20 minutes and at a temperature of 600 °С for 1 hour. During the experiment it was established that film-forming solutions are usable only for 2 to 7 days from the moment of preparation. Using thermal and infra-red – spectroscopic analysis main stages of oxide system formation were retraced. On the surface of the material NaCl, CaCl2, H2PO4·H2O, Ca5(PO4)3Cl, and SiO2 phases are being registered. Presence of the significant amount of pores leads to the essential increase in the specific surface area, creating optimal conditions for the new bone tissue formation. Biological activity of the received material was evaluated in SBF environment. Ca and P content on the surface of the material increased twofold in two weeks. Such material interchanges calcium ions and phosphate ions with solution; silanol groups fix calcium ions, furthering the formation of the layer of amorphous calcium phosphates gradually crystallizing in hydroxyapatite, and other calcium phosphates. Presence of magnesium and sodium on the surface of the samples after their immersion into SBF solution indicates the settling of SBF solution components on the film surface

Synthesis and biological properties of thin-film materials on the basis of SiO2-P2O5-CaO-Na2 system

Thin films for the SiO2–P2O5–CaO–Na2O system are synthesized using sol-gel method. Content of the oxides in the system is 52-18-20-10 wt.% correspondingly. Thin films were produced from film-forming solutions on the single-crystal silicon substrates (model substrate) by extraction at a velocity of 5 mm/s following by heat treatment at a temperature of 60-80 °С for 20 minutes and at a temperature of 600 °С for 1 hour. During the experiment it was established that film-forming solutions are usable only for 2 to 7 days from the moment of preparation. Using thermal and infra-red – spectroscopic analysis main stages of oxide system formation were retraced. On the surface of the material NaCl, CaCl2, H2PO4·H2O, Ca5(PO4)3Cl, and SiO2 phases are being registered. Presence of the significant amount of pores leads to the essential increase in the specific surface area, creating optimal conditions for the new bone tissue formation. Biological activity of the received material was evaluated in SBF environment. Ca and P content on the surface of the material increased twofold in two weeks. Such material interchanges calcium ions and phosphate ions with solution; silanol groups fix calcium ions, furthering the formation of the layer of amorphous calcium phosphates gradually crystallizing in hydroxyapatite, and other calcium phosphates. Presence of magnesium and sodium on the surface of the samples after their immersion into SBF solution indicates the settling of SBF solution components on the film surface