scholarly journals Gel Based Sunscreen Containing Surface Modified TiO2Obtained by Sol-Gel Process: Proposal for a Transparent UV Inorganic Filter

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Marina Paiva Abuçafy ◽  
Eloísa Berbel Manaia ◽  
Renata Cristina Kiatkoski Kaminski ◽  
Victor Hugo Sarmento ◽  
Leila Aparecida Chiavacci
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Chemical Properties ◽  
High Refractive Index ◽  
Inorganic Materials ◽  
Continuous Exposure ◽  
Sol Gel Process ◽  
Surface Modified ◽  
Physical And Chemical ◽  
Gel Formulations

Inorganic UV filters, as titanium dioxide (TiO2), have become attractive because of their role in protecting the skin against the damage caused by the continuous exposure to the sun. However, their high refractive index, responsible for a white residue when applied on the skin, has led to the development of alternative inorganic materials, such as TiO2nanoparticles. Thus, the aim of this study was the development of transparent and stable gel formulations containing surface modified TiO2nanoparticles for application in sunscreens. Also, the physical and chemical properties of formulations containing TiO2nanoparticles were evaluated. The UV absorption spectroscopy analyses indicated that the formulations containing TiO2nanoparticles had a broad protection spectrum. The diffuse reflectance spectroscopy revealed that the use of PTSH surface modified TiO2nanoparticles improved the transparency of the sunscreen formulations compared to that containing commercial ones. The rheology analyses showed that the amount of nanoparticles incorporated in the formulations influences the gel-like or liquid-like behavior. The results showed that the surface modified TiO2nanoparticles are a promising innovative UV filter and the formulations containing these nanoparticles are interesting candidates for being used as sunscreen.

scholarly journals The Influence Of NO/O2 On The NOx Storage Properties Over A Pt-Ba-Ce/γ-Al2O3 Catalyst

2019 ◽  
Vol 17 (1) ◽  
pp. 1459-1465
Author(s):  
Xuedong Feng ◽  
Jing Yi ◽  
Peng Luo
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
No Oxidation ◽  
Test Results ◽  
X Ray Diffraction ◽  
Storage Performance ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
Physical And Chemical ◽  
Al2o3 Catalyst

AbstractWith the purpose of studying the influence of NO/O2 on the NOx storage activity, a Pt-Ba-Ce/γ-Al2O3 catalyst was synthesized by an acid-aided sol-gel method. The physical and chemical properties of the catalyst were characterized by X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results showed that the composition of the catalyst was well-crystallized and the crystalline size of CeO2 (111) was about 5.7 nm. The mechanism of NO and NO2 storage and NOx temperature programmed desorption (NO-TPD) experiments were investigated to evaluate the NOx storage capacity of the catalyst. Pt-Ba-Ce/γ-Al2O3 catalyst presented the supreme NOx storage performance at 350℃, and the maximum value reached to 668.8 μmol / gcat. Compared with O2-free condition, NO oxidation to NO2 by O2 had a beneficial effect on the storage performance of NOx. NO-TPD test results showed that the NOx species stored on the catalyst surface still kept relatively stable even below 350℃.

Structuring-agent role in physical and chemical properties of Mo/SiO2 catalysts by sol-gel method

2018 ◽  
Vol 89 (2) ◽  
pp. 416-425
Author(s):  
William Giovanni Cortés-Ortiz ◽  
Alexander Baena-Novoa ◽  
Carlos Alberto Guerrero-Fajardo
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Gel Method ◽  
Sol Gel Method ◽  
Physical And Chemical ◽  
And Chemical Properties

Infrared Characterization of PMMA-SiO2 Hybrid Glasses Obtained by Sol-Gel Process

2010 ◽  
Vol 1278 ◽  
Author(s):  
L.L. Díaz-Flores ◽  
A. S. López Rodríguez ◽  
P. SifuentesGallardo ◽  
M.A. Hernàndez Rivera ◽  
M.a Garnica Romo ◽  
...  
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
Hybrid Coatings ◽  
Force Microscopy ◽  
Air Atmosphere ◽  
Atomic Force ◽  
Sol Gel Process ◽  
Traditional Process ◽  
And Chemical Properties

AbstractThis work is about the production of hybrid coatings of the system SiO2-PMMA (PMMA, polymethylmethacrylate). These materials have interesting mechanical and chemical properties useful for anticorrosive and wear resistance applications. SiO2-PMMA hybrids were obtained by the sol-gel traditional process, using tetraethylorthosilicate (TEOS) and methylmethacrylate (MMA) by Aldrich Co, as starting reagents. The SiO2:PMMA ratio was varied from 0:1 to about 1:1 at air atmosphere deposition. The coatings were obtained on acrylic sheets and silicon wafers. A diversity of coatings with chemical composition ranging from SiO2 and PMMA to obtain the SiO2-PMMA hybrids were obtained. Infrared (IR) and atomic force microscopy (AFM), were performed to determinate structural and morphological behavior.

Properties of Nano-Hybrid Sol-Gel Materials Synthesized from Colloidal Silica-Silane Containing Epoxy Silane

2007 ◽  
Vol 336-338 ◽  
pp. 2278-2281 ◽  
Author(s):  
Moon Kyong Na ◽  
Dong Pil Kang ◽  
Hoy Yul Park ◽  
Myeong Sang Ahn ◽  
In Hye Myung
Keyword(s):  
Contact Angle ◽  
Colloidal Silica ◽  
Flat Surface ◽  
Coating Layer ◽  
Sol Gel ◽  
Chemical Properties ◽  
Coating Films ◽  
Initial Stage ◽  
Physical And Chemical ◽  
And Chemical Properties

Three kinds of colloidal silica (CS)/silane sol solutions were synthesized in variation with parameters such as different acidity and reaction time. Sol solutions were prepared from HSA CS/ methyltrimethoxysilane (MTMS), LS CS/MTMS and LS CS/MTMS/γ -Glycidoxypropyltri methoxysilane (ES) solutions. In order to understand their physical and chemical properties, sol-gel coating films were fabricated on glass. Coating films on glass, obtained from LS/MTMS sol, had high contact angle, also, much enhanced flat surface in the case of LS/MTMS sol was observed in comparison with HSA/ MTMS sol. From all sol-gel solutions, seasoning effect of for enhancing properties of sol-gel coating layer on glass was observed while such sol-gel solutions were left for 7days. In initial stage of sol-gel reaction, all most of sol solutions used in this work seem to be unstable, formation of coating films was a little hazy and rough. However, improved coating films as observed in 4days later. LS/MTMS/ES sol solutions were synthesized with ES, adding to LS/MTMS sol. Contact angle of LS/MTMS/ES sol-gel coating films decreased, since ES played a role in forming hydrophilic hydroxyl sol. The elastic portion of coating films prepared from LS/MTMS/ES sol increased with addition of ES, but thermal stability decreased a little.

Synthesis and Characterization of N- Doped ZnO-γAl2O3 Nanoparticles for Photo-catalytic Application

2019 ◽  
Vol 18 (2) ◽  
Author(s):  
M. Mansouri ◽  
A. Hosseinvand ◽  
T. Kikhavani ◽  
N. Setareshenas
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Uv Light ◽  
Chemical Properties ◽  
Catalyst Loading ◽  
X Ray Diffraction ◽  
Catalytic Application ◽  
Photo Catalysis ◽  
Doped Zno ◽  
Physical And Chemical

Abstract In this study, photo-catalytic degradation of methyl orange (MO) azo dye was examined by undoped and Ce2O3/ CuO/ N doped ZnO nanoparticles stabilized on γAl2O3. Highest photo-catalytic activity was observed for the N-doped 10 wt. % ZnO-γAl2O3 sample. One of the optimal points with the complete MO decomposition was determined at an initial concentration of 8.25 ppm, pH 3.25, catalyst loading of 0.36 g/L and 12.56 W UV-light irradiation after 120 min. Physical and chemical properties of materials were investigated by X-ray diffraction analysis (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) and UV–visible diffuse reflectance spectroscopy (DRS) method. The experimental data were best fitted by a Langmuir-Hinshelwood approach photo-catalysis developed kinetic reaction rate in the form of $- r = 0.2797\, {I^{0.5}}\, {[Cat.]^{0.5}}\, \, [Dye]{\text{ }}/\, \, \, 1 + 0.1079\, {[Dye]_0}\, + \, 0.4086\, {I^{0.5}}\, {[Cat.]^{0.5}}$.

Structural Defect Formation in Inorganic Sol-Gel Derived Oxides

2005 ◽  
Vol 242-244 ◽  
pp. 143-158 ◽  
Author(s):  
Elena V. Frolova ◽  
Mariya I. Ivanoskaya
Keyword(s):  
Defect Formation ◽  
Complex Structure ◽  
Sol Gel ◽  
Chemical Properties ◽  
Reduction Process ◽  
Molar Ratios ◽  
Glass Forming ◽  
Structural Peculiarities ◽  
Complex Metal Oxides ◽  
Physical And Chemical

The advantages and uniqueness of the Inorganic modification of the Sol-Gel method have already been described. Homogeneous nano-composites as well as some exotic glasses, complex-metal-oxides systems with little glass-forming ability, can be produced by this method. Thus, the obtained materials are characterized by a complex structure that leads to the wide variety of physical and chemical properties. Zirconia-containing materials are of utmost interest because of the mechanical toughness and chemical resistance provided by the presence of ZrO2. In the present work, we report on unusual structural peculiarities of the Zr-O, two types of Zr-Ge-O systems (with Zr>Ge and Zr<Ge molar ratios) and Zr-Ce-Al-O glassy samples, successfully prepared by inorganic modification of the Sol-Gel technique. We tried to elucidate the cause of a self-reduction process in those oxides systems under thermal treatment in air and the way in which structural imperfections impact upon some properties of the materials obtained.

scholarly journals Synthesis of Silica Nanoparticles by Sol-Gel: Size-Dependent Properties, Surface Modification, and Applications in Silica-Polymer Nanocomposites—A Review

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Ismail Ab Rahman ◽  
Vejayakumaran Padavettan
Keyword(s):  
Surface Modification ◽  
Silica Nanoparticles ◽  
Polymer Nanocomposites ◽  
Sol Gel ◽  
Chemical Properties ◽  
Size Dependent ◽  
Recent Developments ◽  
Gel Technique ◽  
Nanoparticles Characterization ◽  
Physical And Chemical

Application of silica nanoparticles as fillers in the preparation of nanocomposite of polymers has drawn much attention, due to the increased demand for new materials with improved thermal, mechanical, physical, and chemical properties. Recent developments in the synthesis of monodispersed, narrow-size distribution of nanoparticles by sol-gel method provide significant boost to development of silica-polymer nanocomposites. This paper is written by emphasizing on the synthesis of silica nanoparticles, characterization on size-dependent properties, and surface modification for the preparation of homogeneous nanocomposites, generally by sol-gel technique. The effect of nanosilica on the properties of various types of silica-polymer composites is also summarized.

Physico-Chemical Properties of Silica Coated Superparamagnetic Magnetite Nanoparticles Synthesized by Non-Seeded Process

2015 ◽  
Vol 1107 ◽  
pp. 267-271
Author(s):  
Sodipo Bashiru Kayode ◽  
Azlan Abdul Aziz
Keyword(s):  
Silica Nanoparticles ◽  
Magnetite Nanoparticles ◽  
Colloidal Suspension ◽  
Sol Gel ◽  
Chemical Properties ◽  
Colloidal Suspensions ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Physico Chemical ◽  
Physical And Chemical

The science of core-shell nanoparticles requires investigation into several physical and chemical properties of the composite nanoparticles. Unlike the conventional sol-gel or the reverse microemulsion micelle method, we presented here a non-seeded process of encapsulating superparamagnetic magnetite nanoparticles (SPMN) with silica. Physico-chemical analysis of the product was used to confirm the result of the coating procedure. Colloidal suspension of SPMN and silica nanoparticles were synthesised through coprecipitation method and modified Stöber method respectively. Afterwards, both colloidal suspensions of SPMN and silica nanoparticles were sonicated to encapsulate the SPMN with silica. Elemental mapping of the composite particles with electron spectroscopy imaging (ESI) confirmed the core-shell micrograph of the SPMN and silica. The X-ray diffraction pattern (XRD) showed the silica shell to be in amorphous form. FTIR analysis further confirmed the chemical properties of the product to be silica coated SPMN.

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