Search results for " sol-gel"
showing 10 items of 12 documents
Ferricytochrome c encapsulated in silica nanoparticles: structural stability and functional properties.
2004
Using a modified sol-gel technique, we have succeeded in encapsulating ferric cytochrome c in silica nanoparticles obtained from hydrolysis and polycondensation of tetramethylorthosilicate. Particles dimensions have been determined with dynamic light scattering; this technique yields an hydrodynamic radius of about 100 nm, each nanoparticle containing about 10(2)-10(3) proteins. If stored in the cold at low ionic strength, nanoparticles are stable for more than one week, even if a slow radius increase with time is observed. CD measurements show that encapsulated proteins exhibit substantially increased stability against guanidinium hydrochloride induced denaturation. Reduction kinetics of e…
Sol-gel synthesis and photocatalytic activity of ZnO-SnO2 nanocomposites
2014
Abstract ZnO–SnO 2 nanocomposites were synthesized by a facile sol–gel synthesis route and characterized through X-ray diffraction, BET specific surface area analysis, UV–vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy. The photocatalytic activity of the samples was tested using the degradation of 4-nitrophenol under UV light as model reaction. The ZnO/SnO 2 molar ratio was varied in order to study its influence on the photoefficiency of the samples. The ZnO–SnO 2 nanocomposites showed higher photoactivity than the pure oxides and in particular the sample with ZnO/SnO 2 mol…
Enhanced one-component spray polyurethane foams via sol-gel microspheres doped with aqueous glycerol
2013
The sol-gel microencapsulation of aqueous glycerol in silica-based microspheres affords functional materials that can be used to cure one-component polyurethane foams (OCF) formulations affording better and greener foam formation. These findings are important and may open the route to more sustainable materials, such as foams, coatings, adhesives, and sealants that are widely utilized in many industrial sectors. © 2013 American Chemical Society.
Sol–Gel Microcapsulation in Silica-Based Particles: A Comparative Study
2011
Comparison between the two main sol–gel/emulsion methods to prepare microparticles made of organosilica doped with a lipophilic molecule shows that entrapment only takes place starting from O/W emulsions. In this case, however, formation of spherical microcapsules, observed when the sol–gel polycondensation is carried out in a W/O microemulsion, does not take place.
The influence of Al doping on the photocatalytic activity of nanostructured ZnO: The role of adsorbed water
2018
Abstract Al doped ZnO nanoparticles (labeled as x% A-ZnO, x = 0.0, 0.5, 1.0, and 1.5) were synthesized by a simple sol-gel method, characterized and tested as photocatalysts for the degradation of a model compound under UV-light irradiation. Diffuse reflectance spectroscopy (DRS) and photoelectrochemical analysis have been performed to evidence their optical and electronic behavior. The structural features of the powders were highlighted by means of specific surface area (SSA) analysis, X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and Raman spectroscopy. Al doping results in enhanced photocatalytic activity of the modified powders with respect to pure ZnO. In particular, the h…
Enhanced Solar Light Photocatalytic Activity of Ag Doped TiO2–Ag3PO4 Composites
2020
Composites comprised of Ag3PO4 and bare TiO2 (TiO2@Ag3PO4) or silver doped TiO2 (Ag@TiO2&ndash
Microcapsule sol-gel dopate per applicazioni industriali ecocompatibili
2012
Optical Fibre NO2 Sensor Based on Lutetium Bisphthalocyanine in a Mesoporous Silica Matrix
2018
International audience; In this article, we describe a NO2 sensor consisting of a coating based on lutetium bisphthalocyanine (LuPc2) in mesoporous silica. The sensor exploits the absorption spectrum change of this material which strongly and reversibly decreases in contact with NO2. NO2 is measured by following the amplitude change in the reflected spectrum of the coating deposited on the tip of a silica fibre. As diffusion of NO2 in LuPc2 is slow, the response time could be slow. To reduce it, the active molecules are dispersed in a mesoporous silica matrix deposited by a sol-gel process (Evaporation Induced Self Assembly) avoiding the formation of large crystals. Doing so, the response i…
Complement proteins regulating macrophage polarisation on biomaterials
2019
[EN] One of the events occurring when a biomaterial is implanted in an host is the protein deposition onto its surface, which might regulate cell responses. When a biomaterial displays a compromised biocompatibility, distinct complement pathways can be activated to produce a foreign body reaction. In this article, we have designed different types of biomaterial surfaces to study the inflammation process. Here, we used different concentrations of (3-glycidoxypropyl)-trimethoxysilane (GPTMS), an organically-modified alkoxysilane as a precursor for the synthesis of various types of sol-gel materials functionalizing coatings for titanium implants to regulate biological responses. Our results sh…