scholarly journals Formation of nanoscopic CaF2via a fluorolytic sol–gel process for antireflective coatings

2015 ◽  
Vol 3 (8) ◽  
pp. 1716-1723 ◽  
Author(s):  
Alexander Rehmer ◽  
Kerstin Scheurell ◽  
Erhard Kemnitz

For the first time transparent antireflective CaF2-coatings were prepared from clear CaF2-sols obtained via the fluorolytic sol–gel synthesis and containing homo-dispersed CaF2 nano-particles.

Author(s):  
Ruohong Sui ◽  
Connor E. Deering ◽  
Rohen Prinsloo ◽  
Christopher B. Lavery ◽  
Nancy Chou ◽  
...  

2-Dimensional TiO2 is synthesized for the first time by a sol–gel self-assembly of Ti–oxoalkoxy–acetate complexes.


RSC Advances ◽  
2014 ◽  
Vol 4 (90) ◽  
pp. 48872-48875 ◽  
Author(s):  
Xinxiang Zhang ◽  
Mengyun Zhuang ◽  
Xia Miao ◽  
Wenmu Su ◽  
Mingyue Lin ◽  
...  

Environment-resistant fluoro-containing antireflective coatings was prepared by a sol–gel process by the co-condensation of tetraethylorthosilicate and 1H,1H,2H,2H-perfluoroalkyltriethoxysilanes (POTS).


2020 ◽  
Vol 96 (1) ◽  
pp. 236-246
Author(s):  
Marta Gallo ◽  
Fabio Giudice ◽  
Mauro Banchero ◽  
Silvia Ronchetti ◽  
Luigi Manna ◽  
...  

Abstract Curcumin is a natural active principle with antioxidant, antibacterial and anti-inflammatory properties. Its use is limited by a low water solubility and fast degradation rate, which hinder its bioavailability. To overcome this problem, curcumin can be delivered through a carrier, which protects the drug molecule and enhances its pharmacological effects. The present work proposes a simple one-pot sol–gel synthesis to obtain a hybrid carrier for curcumin delivery. The hybrid consists of a mesostructured matrix of amorphous silica, which stabilizes the carrier, and hexadecyltrimethylammonium (CTA), a surfactant where curcumin is dissolved to increase its water solubility. The carrier was characterized in terms of morphology (FESEM), physicochemical properties (XRD, FTIR, UV spectroscopy) and release capability in pseudo-physiological solutions. Results show that curcumin molecules were entrapped, for the first time, in a silica-surfactant mesostructured hybrid carrier. The hybrid carrier successfully released curcumin in artificial sweat and in a phosphate buffer saline solution, so confirming its efficacy in increasing curcumin water solubility. The proposed drug release mechanism relies on the degradation of the carrier, which involves the concurrent release of silicon. This suggests strong potentialities for topical administration applications, since curcumin is effective against many dermal diseases while silicon is beneficial to the skin.


Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 128 ◽  
Author(s):  
Kerstin Scheurell ◽  
Erhard Kemnitz

The potential of fluorolytic sol–gel synthesis for a wide variety of applications in the field of optical materials is reviewed. Based on the fluorolytic sol–gel synthesis of nanometal fluorides, sols of complex fluorometalates have become available that exhibit superior optical properties over known classical binary metal fluorides as, for instance, magnesium fluoride, calcium fluoride, or strontium fluoride, respectively. The synthesis of transparent sols of magnesium fluoroaluminates of the general composition MgxAlFy, and fluoroperovskites, [K1−xNax]MgF3, is reported. Antireflective coatings fabricated from MgF2, CaF2, MgxAlFy, and [K1−xNax]MgF3 sols and their relevant properties are comprehensively described. Especially the heavier alkaline earth metal fluorides and the fluorperovskites crystallizing in a cubic crystal structure are excellent hosts for rare earth (RE) metals. Thus, the second chapter reflects the synthesis approach and the properties of luminescent systems based on RE-doped alkaline earth metal fluorides and [K1−xNax]MgF3 phases.


2010 ◽  
Vol 71 ◽  
pp. 28-33 ◽  
Author(s):  
Antônio Hortêncio Munhoz Jr. ◽  
Renato Meneghetti Peres ◽  
L.H. Silveira ◽  
Leonardo Gondim Andrade e Silva ◽  
L.F. de Miranda

Nanocomposites are nanometrical material particles embedded in a specific matrix. The degree of organization of the nanostructures and their properties depend on the nature of the organic and inorganic components of the structure that can generate synergic interactions. Polymeric nanocomposites are related to a class of hybrid materials where inorganic substances of nanometric dimensions are dispersed in a polymeric matrix. In the present work, nanocomposites of nylon 6,12 with different concentrations of pseudoboehmite obtained by sol-gel process were prepared with and without the presence of octadecylamine. After preparation, the samples were irradiated with a 200 kGy radiation dose in an electron accelerator. The pseudoboehmite nano particles were characterized by X-ray diffraction, scanning electron microscopy, differential thermal analysis and thermo gravimetric analysis. The nanocomposites were characterized by thermal and mechanical tests. The addition of pseudoboehmite promoted a reduction of the melting flow during the production of the composites evidencing the interaction of pseudoboehmite with the polymeric matrix, probably modifying its crystalline structure.


Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1078
Author(s):  
Egle Grazenaite ◽  
Edita Garskaite ◽  
Zivile Stankeviciute ◽  
Eva Raudonyte-Svirbutaviciene ◽  
Aleksej Zarkov ◽  
...  

For the first time to the best of our knowledge, cobalt-chromium spinels CoCr2−xGaxO4 with different amounts of gallium (x = 0–2 with a step of 0.5) were synthesized via the aqueous sol–gel route as ceramic pigments. The phase composition, crystallite size, morphological features, and color parameters of new compositions and their corresponding ceramic glazes were investigated using XRD, CIELab, SEM, and optical microscopy. It was demonstrated that the formation of single-phase CoCr2−xGaxO4 samples was problematic. Full substitution of Cr3+ by Ga3+ ion in the spinel resulted in the formation of light blue powders, which yielded violetish blue color for the corresponding ceramic glaze.


2019 ◽  
Vol 07 (01n02) ◽  
pp. 1950002
Author(s):  
Nadir Lalou ◽  
Ahmed Kadari

This work proposes the synthesis of nanocrystalline calcium oxide (CaO) pure and doped with different concentrations of lithium (Li[Formula: see text]) ions by sol–gel process. Calcium nitrate (Ca(NO[Formula: see text]4H2O; 99.99%) and lithium nitrate (LiNO3; 99.99%) were used as precursors. The synthesized powders were characterized by several techniques such as: UV-Vis transmission spectroscopy, Fourier Transform Infra-red spectroscopy (FT-IR) and X-ray diffraction (XRD). The main objective of this paper is to study the influence of lithium (Li[Formula: see text] ratio) on the structural and optical properties of synthesized powders. The band gap values decreased with the increasing of Li[Formula: see text] ions in CaO lattice; the slight change in the band gap was directly related to the energy transfer between the CaO excited states and the 2s levels of Li[Formula: see text] ions. The influence of Li[Formula: see text] doping on the physical properties of CaO nanocrystalline will be studied for the first time in this work; no literature has previously published this kind of impurities.


1990 ◽  
Vol 180 ◽  
Author(s):  
G.W. Dale ◽  
H.H. Fox ◽  
Brian J.J. Zelinski ◽  
Laura Weller-Brophy

SiO2-TiO2 sol-gel solutions and synthesis techniques have been developed to produce thin films of proper index, thickness and quality for use as planar waveguides. The composition of the synthesized films ranged from 50 to 68 mole % TiO2 and produced layers with indices ranging from 1.7 to 1.8. Final film thicknesses ranged from 1000 to 3000 A and varied as a function of the coating chemistry and conditions. Also, changes in film shrinkage and index with heat treatment were determined and compared to literature data on similar films used as antireflective coatings. Finally, confirmation of the waveguiding qualities of these films was made through prism coupler measurements conducted by the University of Arizona Optical Sciences Center.


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