scholarly journals New SiO2/Caffeic Acid Hybrid Materials: Synthesis, Spectroscopic Characterization, and Bioactivity

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 394 ◽  
Author(s):  
Michelina Catauro ◽  
Federico Barrino ◽  
Giovanni Dal Poggetto ◽  
Giuseppina Crescente ◽  
Simona Piccolella ◽  
...  
Keyword(s):  
Caffeic Acid ◽  
Hybrid Materials ◽  
Structural Changes ◽  
Sol Gel ◽  
Functional Materials ◽  
Spectroscopic Characterization ◽  
Silica Matrix ◽  
Materials Synthesis ◽  
Vis Spectroscopy ◽  
Ft Ir

The sol–gel route represents a valuable technique to obtain functional materials, in which organic and inorganic members are closely connected. Herein, four hybrid materials, containing caffeic acid entrapped in a silica matrix at 5, 10, 15, and 20 wt.%, were synthesized and characterized through Fourier-Transform Infrared (FT-IR) and Ultraviolet-Visible (UV–Vis) spectroscopy. FT-IR analysis was also performed to evaluate the ability to induce the hydroxyapatite nucleation. Despite some structural changes occurring on the phenol molecular skeleton, hybrid materials showed scavenging properties vs. 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2′-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) radical cation (ABTS•+), which was dependent on the tested dose and on the caffeic acid wt.%. The SiO2/caffeic acid materials are proposed as valuable antibacterial agents against Escherichia coli and Enterococcus faecalis.

scholarly journals New SiO2/Caffeic Acid Hybrid Materials: Synthesis, Spectroscopic Characterization and Bioactivity

2019 ◽  
Author(s):  
Michelina Catauro ◽  
Federico Barrino ◽  
Giovanni Dal Poggetto ◽  
Giuseppina Crescente ◽  
Simona Piccolella ◽  
...  
Keyword(s):  
Caffeic Acid ◽  
Hybrid Materials ◽  
Structural Changes ◽  
Sol Gel ◽  
Functional Materials ◽  
Spectroscopic Characterization ◽  
Silica Matrix ◽  
Materials Synthesis ◽  
Vis Spectroscopy ◽  
Ft Ir

Sol-gel route represents a valuable technique to obtain functional materials, in which organic and inorganic members are closely connected. Herein four hybrid materials, containing caffeic acid entrapped in a silica matrix at 5, 10, 15 and 20 wt%, were synthesized and characterized through FT-IR and UV-Vis spectroscopy. FT-IR analysis was also performed to evaluate the ability to induce the hydroxyapatite nucleation. Despite some structural changes occurred on the phenol molecular skeleton, hybrid materials showed scavenging properties vs DPPH and ABTS+ radicals, which was dependent on the tested dose and on the caffeic acid wt%. Finally, the SiO2/caffeic acid materials have been proposed as valuable antibacterial agents against Escherichia coli and Enterococcus faecalis.

Synthesis and Luminescence Properties of 1,10-Phenanthroline Terbium/Polyvinyl Alcohol Hybrid Functional Materials

2010 ◽  
Vol 663-665 ◽  
pp. 316-319
Author(s):  
Hua Zhang ◽  
Lei Zhou
Keyword(s):  
Polyvinyl Alcohol ◽  
Hybrid Materials ◽  
Hybrid Material ◽  
Fluorescence Spectra ◽  
Photophysical Properties ◽  
Sol Gel ◽  
Functional Materials ◽  
Hybrid Functional ◽  
Separation Processes ◽  
Ft Ir

A series of 1, 10-phenanthroline terbium/ polyvinyl alcohol hybrid materials with different coupling agent contents were prepared by sol-gel method. The morphology and photophysical properties were investigated. FT-IR was applied to characterize the structure of the obtained hybrid material, SEM and fluorescence spectra were applied to characterize the performance of the hybrid material. The result shows that the phase separation processes and the fluorescence quenching were avoided and the optical performance of hybrid materials were improved effectively.

scholarly journals Synthesis, Structural, Morphological and Thermal Characterization of Five Different Silica-Polyethylene Glycol-Chlorogenic Acid Hybrid Materials

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1586
Author(s):  
Michelina Catauro ◽  
Pavel Šiler ◽  
Jiří Másilko ◽  
Roberta Risoluti ◽  
Stefano Vecchio Ciprioti
Keyword(s):  
Polyethylene Glycol ◽  
Chlorogenic Acid ◽  
Hybrid Materials ◽  
Sol Gel ◽  
Antibacterial Properties ◽  
Silica Matrix ◽  
Sem Images ◽  
Fixed Amount ◽  
Organic Components ◽  
Free Material

The present study investigated the structure, morphology, thermal behavior, and bacterial growth analysis of novel three-component hybrid materials synthesized by the sol-gel method. The inorganic silica matrix was weakly bonded to the network of two organic components: a well-known polymer such as polyethylene glycol (PEG, average molar mass of about 4000 g/mol), and an antioxidant constituted by chlorogenic acid (CGA). In particular, a first series was made by a 50 wt% PEG-based (CGA-free) silica hybrid along with two 50 wt% PEG-based hybrids containing 10 and 20 wt% of CGA (denoted as SP50, SP50C10 and SP50C20, respectively). A second series contained a fixed amount of CGA (20 wt%) in silica-based hybrids: one was the PEG-free material (SC20) and the other two contained 12 and 50 wt% of PEG, respectively (SP12C20 and SP50C20, respectively), being the latter already included in the first series. The X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images of freshly prepared materials confirmed that all the materials were amorphous and homogeneous regardless of the content of PEG or CGA. The thermogravimetric (TG) analysis revealed a higher water content was adsorbed into the two component hybrids (SP50 and SC20) because of the availability of a larger number of H-bonds to be formed with water with respect to those of silica/PEG/CGA (SPC), where silica matrix was involved in these bonds with both organic components. Conversely, the PEG-rich materials (SP50C10 and SP50C20, both with 50 wt% of the polymer) retained a lower content of water. Decomposition of PEG and CGA occurred in almost the same temperature interval regardless of the content of each organic component. The antibacterial properties of the SiO2/PEG/CGA hybrid materials were studied in pellets using either Escherichia coli and Enterococcus faecalis, respectively. Excellent antibacterial activity was found against both bacteria regardless of the amount of polymer in the hybrids.

scholarly journals Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Abdul Hafeez ◽  
Zareen Akhter ◽  
John F. Gallagher ◽  
Nawazish Ali Khan ◽  
Asghari Gul ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Spectroscopic Characterization ◽  
Spectroscopic Techniques ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Electrically Conductive ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Ft Ir

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

Effect of Surfactants on Stability of Colloidal Sols as Precursors in Sol-Gel Encapsulation

2009 ◽  
Vol 415 ◽  
pp. 57-60 ◽  
Author(s):  
Ioana Lacatusu ◽  
Nicoleta Maria Badea ◽  
Aurelia Meghea
Keyword(s):  
Sol Gel ◽  
Functional Materials ◽  
Flavonoid Compound ◽  
Quaternary Salts ◽  
Bioactive Properties ◽  
Nir Fluorescence ◽  
Scattering Measurements ◽  
Ft Ir ◽  
Preparation Route ◽  
Gel Preparation

This paper aims to study the effect of three alkyl quaternary salts on stability of colloidal sols further used as water-insoluble oligomers for encapsulation of an active flavonoid compound – quercitin. The preparation procedure is described and practical remarks on silica-based sol-gels are included. It is also demonstrated how to exploit the sol-gel preparation route in order to improve the thermal resistance of quercitin and to increase an optical function - fluorescence. The evolution in time of competitive hydrolysis and condensation processes has been observed by dynamic light scattering measurements. The sol-gel materials with entrapped quercitin molecule have been characterised by spectral methods (FT-IR, UV-VIS-NIR), fluorescence and by thermal analysis as well. Sol-gel materials doped with active flavonoid compound may be used in preparation of some functional materials with bioactive properties.

Optical Properties of ATO Sol-gel Coated Carbon Fibers

2012 ◽  
Vol 1454 ◽  
pp. 221-226
Author(s):  
Brandon Richard ◽  
Norma Alcantar ◽  
Andrew Hoff ◽  
Sylvia Thomas
Keyword(s):  
Heat Treatment ◽  
Optical Properties ◽  
Carbon Fibers ◽  
Sol Gel ◽  
Functional Materials ◽  
Additional Material ◽  
Heat Treated ◽  
Ft Ir ◽  
Recent Trends ◽  
Thermal Infrared Radiation

ABSTRACTRecent trends in composite research include the development of structural materials with multiple functionalities. In new studies, novel materials are being designed, developed, modified, and implemented into composite designs. Typically, an increase in functionality requires additional material phases within one system. The presence of excessive phases can result in deterioration of individual or overall properties. True multi-functional materials must maintain all properties at or above the minimum operating limit. In this project, samples of Sb-doped SnO2(ATO) sol-gel solutions are used to coat carbon fibers and are heat treated at a temperature range of 200 – 500 °C. Results from this research are used to model the implementation of sol-gel coatings into carbon fiber reinforced multifunctional composite systems. This research presents a novel thermo-responsive sol-gel/ (dopant) combination and evaluation of the actuating responses due to various heat treatment temperatures. While ATO is a well-known transparent conductive material, the implementation of ATO on carbon fibers for infrared thermal reflectivity has not been examined. These coatings serve as actuators capable of reflecting thermal infrared radiation in mid-range and near-range wavelengths (λ). By altering the ATO sol gel thickness and heat treatment temperatures, optimal optical properties are obtained. While scanning electron microscopy (SEM) is used for imaging, electron diffraction spectroscopy (EDS) is used to verify the compounds present in the coatings. Fourier transform infrared (FT-IR) spectroscopy was performed to analyze the reflectivity in the infrared spectra and analyze the crystal structures after heat treatments.

scholarly journals Synthesis of SiO2-TiO2:Yb3+ glass-ceramics and characterization of structure and optical properties

2017 ◽  
Vol 1 (T1) ◽  
pp. 114-121
Author(s):  
Thanh Tat Huynh ◽  
Van Thi Thanh Tran
Keyword(s):  
Sol Gel ◽  
Glass Ceramics ◽  
Xrd Analysis ◽  
Silica Matrix ◽  
Photoluminescence Intensity ◽  
Raman Spectroscopic ◽  
Characteristic Emission ◽  
Ft Ir ◽  
Average Size ◽  
20 Nm

In this work, the monoliths of 85 % SiO2-15 % TiO2 doped Yb3+ ions at different contents have been prepared by sol-gel method. The measurement of FT-IR, Raman spectroscopic and XRD analysis show the formation of anatase TiO2 nanocrystals with average size about 15–20 nm in silica matrix. Moreover, the pyrochlore crystals of Yb2Ti2O7 begin to form in the samples when content of Yb3+ reaches to 1 mol %. TiO2 Yb3+ 2F7/2 2F5/2 truyền năng lƣợng kích thích UV EV EC mức khuyết tật 974 nm The energy transferred from TiO2 crystals to Yb3+ ions is proven by the characteristic emission spectrum of Yb3+ at the wavelength of 980 nm when the samples are excited by the wavelength of 300 nm. The photoluminescence intensity is highest at 0.1% mol of Yb3+ and gradually decreases with doping content

Temperature and Oxygen Sensing Properties of Ru(II) Covalently-Grafted Sol–Gel Derived Ormosil Hybrid Materials

2016 ◽  
Vol 16 (4) ◽  
pp. 4023-4028 ◽  
Author(s):  
Haoran Zhang ◽  
Bingfu Lei ◽  
Hanwu Dong ◽  
Yingliang Liu ◽  
Mingtao Zheng ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Thermal Activation ◽  
Sol Gel ◽  
Oxygen Quenching ◽  
Temperature Quenching ◽  
Excited State Lifetime ◽  
Network Modifier ◽  
The Matrix ◽  
Ft Ir ◽  
Sensing Sensitivity

In this article, oxygen and temperature-sensing hybrid materials consisting of [Ru(Phen)3]2+ portions covalently-grafted onto the sol–gel derived ormosil network were prepared by co-condensation of tetraethoxysilane (TEOS) using n-octyltriethoxysilane as the network modifier. For comparison purposes, the hybrid materials in which [Ru(Phen)3]2+ were conventionally physically-incorporated into the matrix were also prepared. The obtained hybrid materials were characterized by Fourier transform infrared (FT-IR), luminescence intensity oxygen quenching Stern-Volmer plots, temperature quenching plots and excited-state lifetime. The near linear Stern-Volmer plots can be attributed to the approximate heterogeneous environment of the luminophore within the ormosil materials. The results reveal that the covalently-grafted sample is more sensitive to O2, and has a higher sensing sensitivity and a higher thermal activation energy compared to the physically-incorporated one, since these Ru(II) molecules are strongly covalently-grafted onto the Si–O network via the CH2–Si bonds and less –OH group.

Synthesis and Characterization of Siloxane-Polyurethane Hybrid Materials

2008 ◽  
Vol 396-398 ◽  
pp. 481-484
Author(s):  
Rodrigo Jiménez-Gallegos ◽  
L. Téllez-Jurado ◽  
Luis M. Rodríguez-Lorenzo ◽  
Julio San Román
Keyword(s):  
Hybrid Materials ◽  
Sol Gel ◽  
Proton Nuclear Magnetic Resonance ◽  
X Ray Diffraction ◽  
Organic Part ◽  
Sol Gel Process ◽  
Nmr Techniques ◽  
Ft Ir ◽  
Characterization Of Materials

This paper focuses on the preparation of siloxane-polyurethane hybrid materials using a sol-gel method. The global aim of the project is to tailor mechanical properties, degradability rate, bioactivity and biocompatibility to design scaffolds for musculoskeletal applications. A series of seven hybrid materials were synthesized with varying the proportion of polydimethylsiloxane (PDMS), and Polyurethane (PU). The organic part ratios (by weight) employed were (% PDMS:% PU) 30:0, 35:5, 20:10, 15:15, 10:20, 5:25, and 0:30. The organic part was reacted with constant 70 % TEOS to obtain the hybrid materials. A sol-gel process was selected for the synthesis of the hybrids. The characterization of materials was carried out by the fourier-infrared spectroscopy (FT-IR), x-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electronic microscopy (SEM) and proton nuclear magnetic resonance (1H-NMR) techniques in order to analyze the structure, microstructure and chemical composition of the hybrid materials. Gelification time depends on the proportion of PU used. When no PU is employed, the gel time is 8 hours but it rises up to 18 days for 30 % of polyurethane. Materials range from opaque to translucent but with a greater fragility for greater amounts of polyurethane. No differences in the bonding of materials could be appreciated.

scholarly journals Tracking dynamic structural changes in catalysis by rapid 2D-XANES microscopy

2021 ◽  
Vol 28 (5) ◽  
Author(s):  
Saba Alizadehfanaloo ◽  
Jan Garrevoet ◽  
Martin Seyrich ◽  
Vadim Murzin ◽  
Johannes Becher ◽  
...  
Keyword(s):  
Partial Oxidation ◽  
Structural Changes ◽  
Functional Materials ◽  
Methane Combustion ◽  
Spectroscopic Characterization ◽  
Frame Rate ◽  
High Time Resolution ◽  
Imaging Method ◽  
Full Field ◽  
Oxidation Of Methane

Many processes and materials in heterogeneous catalysis undergo dynamic structural changes depending on their chemical environment. Monitoring such dynamic changes can be challenging using conventional spectroscopic characterization tools, due to the high time resolution required. Here, a high-resolution 2D X-ray camera operating at 50 Hz full-frame rate was synchronized with a QEXAFS monochromator, enabling rapid spectro-microscopic imaging with chemical contrast over individual pixels. This was used to monitor chemical gradients within a model Pt/Al2O3 catalyst during catalytic partial oxidation of methane to synthesis gas. The transition from methane combustion (partly oxidized Pt) to combustion-reforming and partial oxidation (fully reduced Pt) was observed by a characteristic reduction front, which progressed from the end of the catalyst bed towards its beginning on the second time scale. The full-field QEXAFS imaging method applied here allows acquisition of entire XANES spectra `on the fly' in a rapid and spatially resolved manner. The combination of high spatial and temporal resolution with spectroscopic data offers new opportunities for observing dynamic processes in catalysts and other functional materials at work. The methodology is flexible and can be applied at beamlines equipped with a QEXAFS or other fast-scanning monochromators and a suitable sample environment for gas phase analytics to allow for catalytic studies at the same time.

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