Special Issue "Sol-Gel Chemistry. From Molecule to Functional Materials"
A special issue of Molecules (ISSN 1420-3049).
Deadline for manuscript submissions: 31 October 2018
One of the main challenges in materials science is to find effective strategies to organize the matter in terms of properties: Chemical, physical, etc. In this respect, bottom up approaches based on the self-assembly of molecules at the nanometric scale to form larger structures need to be considered. In particular, the sol-gel process (called inorganic polymerization) has emerged as one of the most important routes for preparing organized materials. It is, thus, important for Molecules to dedicate a Special Issue to this process, since it is perfectly compatible with all kinds of chemistry. This Special Issue will contain contributions discussing all the aspects that are broadly indicated by the keywords. Reviews articles by experts in the field of sol-gel, organosilica, porous hybrid materials and self-assembly will be welcome.Prof. Ahmad Mehdi
Dr. Sébastien Clément
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- Functional oxide
- Hybrid materials
The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.
Author: Xue-Ran Deng
Affiliation: University of Electronic Science and Technology of China | UESTC · Department of Electronic Science and Technology
Tentative title: Fabrication of refractive index tunable coating with moisture-resistant function based on the homogeneous embedding structure
Author: Malgorzata Adamczyk,
Affiliation: Prodziekan ds. Dydaktycznych Kierunków Mechatronika i Inżynieria Materiałowa, Poland
Tentative title: Electric and magnetic properties of PFN ceramics
Author: Rafael Luque
Affiliation: Departamento de Quimica Organica,Universidad de Cordoba
Campus de Rabanales Edificio Marie Curie (C-3) Ctra Nnal IV, Km. 396E-14014 Cordoba (Spain)
Tentative title: Sol-gel synthesis of encapsulated lipases/laccases/peroxidases for the esterification of valeric acid: towards novel biofuels
Author: Andrea S. S. de Camar
Affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, Brazil
Tentative title: Host-guest luminescent materials based on highly emissive species loaded into versatile sol-gel hosts
Author: Parola Stéphane
Affiliation: Laboratoire de Chimie UMR ENS-CNRS-UCBL 5182, University of Lyon (France)
Tentative title: Functional materials by entrapment of nanoparticles in composite xerogels or aerogels
Author: M. Clara Gonçalves1,2*, H Cristina Vasconcelos
1 Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
2 CQE, Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Universidade dos Açores, Ponta Delgada, Portugal.
Abstract: In addition to its traditional application in white pigments, nanocrystlline titania optoelectronic and photocatalytic properties grant new technological applications. Its wide band gap (~3.2 eV) enables its use in photochemical degradation of toxic chemicals, as a bactericide / anti-fungicide agent, in energy conversion in solar cells, or as an electrode material in lithium batteries. All the properties performance is, nevertheless, strongly dependent on crystallinity, particle size, and surface structure. Sol-gel method is one of the most widely used to synthesise TiO2 films and NPs. However, sol-gel products are mostly oxy-hydrated amorphous phases, being severe heat-treatments (T 400ºC) needed to promote crystallization, where the control over size and shape are difficult to achieve.
Photocatalytic performance of amorphous TiO2 thin films doped with N is studied. Films of TiO2-xNx compositions, with N concentrations up to x = 0,75 (25 at.%), are prepared by sol-gel processing followed by spin-coating onto Si(100) wafers, glass slides and CaF2 substrates. The identification and quantification of different Ti-O-Ti, N-Ti-O and Ti-N-Ti bondings is achieved by X-ray photoemission spectroscopy (XPS) and Vacuum ultraviolet (VUV) light scattering. Photoabsorption spectra of oxynitride thin films is observed in the energy range 3.9–10.8 eV (320–115 nm), changing the amorphous titania films paradigm in photocatalysis.
Amorphous titania nanoparticles are synthetized by a novel, eco-friendly, base-catalysed sol-gel methodology. Cotton and polyester textile matrixes are impregnated with amorphous titania nanoparticles, aiming bactericide hospital applications. Titania nanoparticles functionalization with amine groups and bioconjugation with chitosan polymer favour textile impregnation efficiency and bactericide performance. All synthesized nanoparticles (titania, titania functionalized and titania bioconjugated) and all impregnated textiles (cotton and polyester matrices) exhibit bactericide performance, being a promising tool in hospital infections combat, and changing the amorphous titania nanoparticle paradigm as bactericide.
Author: M. Clara Gonçalves
Affiliation: Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
Abstract: Silica (SiO2) is one of the most abundant minerals in the earth crust (~75%), making it a favorite raw material ever since; furthermore, its presence in human body allows its use as a biomaterial, where its presence in dentistry, orthopedics, and dermatology become a commonplace. Recently sol-gel SiO2 nanoparticles (NPs) appear as new promising applications in a wide range of biomedical and pharmaceutical applications, namely as drug/target delivery, gene and imaging therapies or even theranosis, where they stand out for their high biocompatibility, hydrophilicity, enormous flexibility for surface modification with a high payload capacity, and prolonged blood circulation time. The sol-gel process is an extremely versatile bottom-up methodology, offering a wide range of chemical possibilities, namely full scale pH processing.
In situ NPs silica functionalization, by introducing organic functional groups during the sol-gel process (forming an ORganically MOdified SILica matrix, known as ORMOSIL), allows easy chemical conjugation/decoration of biomolecules at the ORMOSIL NPs surface and/or the load with either hydrophilic or hydrophobic drugs/dyes.
But sol-gel silica NPs found technological applications in wide range of fields beyond medicine and pharmacy. Areas such technical textiles, drinking and waste water treatment, catalysis, adsorption, chromatography, sensor technology, gas storage, optics and photonics, magnetism and electronics are familiar with silica chemistry. Actually, sol-gel hybrid silica matrices were taken further by the in situ co-polymerization of silanol groups and cellulose acetate polymers, aiming new hybrid cellulose acetate-silica ultrafiltration membranes for water treatment or artificial organs in near future.
This review surveys some of the emerging approaches in the field of sol-gel silica NPs aiming biomedical applications.
Author: Leda Maria Saragiotto Colpini
Title: Photocatalytic degradation of textile dye orange-122 via electrospray mass spectrometry
Abstract: This work attend with the study of the application potential of catalytic materials (Zn/TiO2) obtained by the sol gel method, in environmental decontamination processes through photodegradation reactions of textile dyes, monitored by electrospray mass spectrometry. The synthesis of the catalysts was performed according to a 2² factorial design with repetition at the central point, where the calcination temperatures and the zinc metallic load were varied. The catalysts were characterized by determination of the zero point of charge, specific surface area, X-ray diffraction and scanning electron microscopy with energy dispersive X-ray and the photocatalytic tests were carried out in batch in the presence of sunlight.
Author: Clément GENET, Marie-Joëlle MENU, Marie GRESSIER, Florence ANSART
Affiliation: CIRIMAT, Université de Toulouse, CNRS INPT UPS, UMR 5085, 118 Route de Narbonne - 31062 Toulouse Cedex 09, France
Title: Innovative sol formulations to develop anticorrosion hybrid sol-gel coatings
Abstract: The aim is to improve the aluminium alloy corrosion resistance by Organic-Inorganic Hybrid (OIH) sol-gel coatings. Coatings are obtained from unusual formulations with precursors mixing: glycidoxypropyltrimethoxysilane (GPTMS), zirconium propoxide (TPOZ) and aluminium tri-sec-butoxide (ASB) before been compared to more classical sol formulations. In each case, a corrosion inhibitor is also incorporated to improve the anti-corrosion performances.
Coatings from sols based on GPTMS/TPOZ/ASB exhibit anti-corrosion properties even for a thickness lower than 4 µm. Furthermore, contact angle measurements showed hydrophobic properties of these coatings. To understand these phenomena, NMR analyses were performed and correlations have been established between microstructure and working properties.
Author: Pauline SAVIGNAC, Marie-Joëlle MENU, Marie GRESSIER, Bastien DENAT ,
Y. EL KHADIR, Stephan MANOV, Florence ANSART
Affiliation: 1 VM Building Solutions, « Les Mercuriales » Tour du Ponant, 40 rue Jean Jaurès, 93170 Bagnolet, France; 2 CIRIMAT, Université de Toulouse, CNRS INPT UPS, UMR 5085, 118 Route de Narbonne - 31062 Toulouse Cedex 09, France
Title: Improvement of adhesion properties and corrosion resistance of sol-gel coatings on zinc
Abstract: The main goal of this study was to improve both the corrosion resistance and the adhesion properties of preweathered zinc substrates by the deposit of a hybrid sol–gel layer. To reach this double objective, a choice between two formulations (TEOS-MAP or GPTMS-ASB) was firstly made from the results obtained by microstructural characterizations (after climatic chamber test, salt spray test, shock test and/or scratch test).
Several analyses were performed and the best formulation was obtained by adding a new precursor (UPS) in controlled conditions, detailed in this paper
Author: Crina Anastasescu 1, Silviu Preda1, Radu Socoteanu 1, Daniel Angelescu 1, Jose Maria Calderon-Moreno 1, Adriana Rusu 1, Gabriel Plavan 2, Stefan Strungaru 2, Mariuca Gartner 1, Mihai Anastasescu 1, Ioan Balint 1, Maria Zaharescu 1
Affiliation: 1 “Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202 Spl. Independentei, 060021, Bucharest, Romania
2 “Alexandru Ioan Cuza” University of Iasi, 11 Carol I Blvd., 700506 Iași, Romania
Title: Tubular and spherical SiO2 obtained by sol gel method for enzyme immobilization
Abstract: A wide range of hybrid biomaterials has been designed in order to sustain various industrial and bioremediation processes, by associating the sol gel SiO2 matrix with various biologically active compounds (enzymes, antibodies). The immobilization of enzymes on silica is looking for an improving of the biocatalysts efficiency in terms of endurance and economic costs, the SiO2 being a widespread, chemical stable and non-toxic material.
Our present work is meant to disclose the significant potential of amorphous SiO2 displaying different morphologies for enzymes immobilization and competitive biocatalysts developing. The synthesis protocol and structural characterization of spherical and tubular SiO2 obtained by sol gel method are deeply investigated in connection with the subsequent immobilization of lipase from Rhizopus orizae. The immobilization is led at pH 6, lower than the isoelectric point of lipase and higher than the isoelectric point of silica which is meant to sustain the physical interactions of the enzyme with the SiO2 matrix. In this sense, the morphological, textural and surface properties of spherical and tubular SiO2 were investigated by SEM, Nitrogen sorption, PZC measurement, while the formation and characterization of hybrid organic inorganic complex was followed by UV-VIS, FTIR-ATR and Fluorescence Spectroscopy. The degree of enzymes immobilization on SiO2 with different morphologies as depicted from TOC measurements is here discussed
Authors: Yanhui Wang, Maroua Bouchneb, Johan G. Alauzun and P. Hubert Mutin
Title: Tuning mesoporous TiO2 morphology and texture by non-hydrolytic sol gel syntheses
Abstract: The development of powerful synthetic methodologies is paramount in the design of advanced nanostructured materials. Owing to its remarkable properties and low cost, nanostructured TiO2 is widely investigated for applications such as photocatalysis, energy conversion, or energy storage. In this article we report the synthesis of mesoporous TiO2 by 3 different non-hydrolytic routes, and we investigate the influence of the presence and nature of the solvent on the morphology, structure and texture of the materials. The first route is the well-known ether route, based on the reaction of TiCl4 with iPr2O. The second and third routes, which have not been previously described for the synthesis of mesoporous TiO2, involve the reaction of Ti(OiPr)4 with acetophenone and benzoic anhydride, respectively. All materials were characterized by XRD, N2 physisorption, and SEM.By playing on the non-hydrolytic route used and on the reaction conditions (no solvent, in toluene, in squalane), it is possible to tune the morphology and texture of the TiO2. Thus, mesoporous or hierarchical mesoporous/macroporous TiO2 were obtained by spontaneous aggregation of anatase nanoparticles, either rounded nanoparticles or nanorods.
Author: Ahmad Mehdi
Affiliation: Institut Charles Gerhardt Montpellier, Montpellier, France
Title : Europium-doped sol-gel SiO2 based glasses: Effect of the europium source and content, the magnesium addition and the thermal treatment on their photoluminescence properties
Abstract : Rare-earth doped silica-based glasses lead the optical materials due to their tailorable spectroscopic and optical properties. In this context, we took advantage of the Sol-Gel process to prepare various Eu-doped silica glasses to study their luminescent properties before and after annealing at 900°C. The effect of magnesium on these properties was studied in comparison with Mg-free-glass. Using TEM, nitrogen sorption, XRD and FT-IR, we confirmed that the magnesium modifies the glass structure and the thermal treatment eliminates the aqueous environment, modifying the structure ordering. The emission spectra and the decay time curves show the advantages of the Mg addition and the annealing on the photoluminescent properties.