Sol-Gel Method Applied to Crystalline Materials

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Hybrid and Composite Crystalline Materials".

Deadline for manuscript submissions: closed (28 February 2021) | Viewed by 18167

Special Issue Editors


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Guest Editor
Department of Engineering, University of Campania “Luigi Vanvitelli”, Via Roma 29, I-81031 Aversa, Italy
Interests: sol-gel technology; biomaterials; bioglass; organic-inorganic hybrid materials; drug delivery; thin films
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Special Issue Information

Dear Colleagues,

Sol–gel chemistry is a versatile synthesis used to produce modern materials at near-room temperature. Glasses, ceramics, composites, and new hybrid materials that are not easy to obtain using other methods have been, instead, obtained in the last three decades and are widely used today. This technique is used principally for the production of materials by means of a colloidal solution (sol) that operates as a precursor leading to the formation of a 3D inorganic network (gel) of either discrete particles or network polymers. Changing the chemical composition, many parameters of the sol–gel process can be adapted to control the properties and the microstructure of the obtained materials. Sol-gel technology is a multidisciplinary science which allows the expansion of materials for many applications: catalysts, optics, electronics, energy, space, biosensors, bioglass, medicine. and so on. In fact, the sol–gel technique is one of the oldest methods of crystal growth and makes use of cheap and available materials.

In particular, the purpose of this Special Issue is to publish high-quality research papers as well as review articles addressing recent advances on the Sol–Gel Method Applied to Crystalline Materials, describing the fundamental principles of crystallization of sol–gel systems in solution.

A study and comprehension of methods and mechanisms of the crystallization process for colloidal systems at temperatures less than 100 °C would allow a significant development of new materials using low-temperature sol–gel synthesis.

Potential topics include preparation methods, material characteristics, and applications of powder electrode materials.

Prof. Dr. Alessandro Dell'Era
Prof. Dr. Michelina Catauro
Guest Editors

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Keywords

  • Biomaterials
  • Nanoparticles
  • Thin films and coatings
  • Organic–inorganic hybrid materials
  • Catalysts
  • Sensors and biosensors
  • Energy
  • Optics

Published Papers (5 papers)

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Editorial

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3 pages, 158 KiB  
Editorial
Sol–Gel Method Applied to Crystalline Materials
by Alessandro Dell’Era and Michelina Catauro
Crystals 2021, 11(8), 903; https://doi.org/10.3390/cryst11080903 - 31 Jul 2021
Cited by 1 | Viewed by 1565
Abstract
Sol–gel chemistry is a versatile synthesis used to produce modern materials at near-room temperature [...] Full article
(This article belongs to the Special Issue Sol-Gel Method Applied to Crystalline Materials)

Research

Jump to: Editorial

21 pages, 6690 KiB  
Article
Synthesis and Characterization of Polymeric (PMMA-PVA) Hybrid Thin Films Doped with TiO2 Nanoparticles Using Dip-Coating Technique
by Ahmad Alsaad, Abdul Raouf Al Dairy, Ahmad Ahmad, Issam A. Qattan, Shatha Al Fawares and Qais Al-Bataineh
Crystals 2021, 11(2), 99; https://doi.org/10.3390/cryst11020099 - 24 Jan 2021
Cited by 39 | Viewed by 4504
Abstract
We report the synthesis of hybrid thin films based on Poly(MethylMethAcrylate) (PMMA) and Poly(VinylAlcohol) (PVA), doped with different concentrations of titanium dioxide nanoparticles (TiO2 NPs). As-prepared thin films of (PMMA-PVA) doped by TiO2 NPs (wt.% = 2%, 4%, 8%, and 16%) [...] Read more.
We report the synthesis of hybrid thin films based on Poly(MethylMethAcrylate) (PMMA) and Poly(VinylAlcohol) (PVA), doped with different concentrations of titanium dioxide nanoparticles (TiO2 NPs). As-prepared thin films of (PMMA-PVA) doped by TiO2 NPs (wt.% = 2%, 4%, 8%, and 16%) are deposited on glass substrate. Transmittance (T%), reflectance (R%), absorption coefficient (α), optical constants (n and k), and optical dielectric functions (ε1 and ε2) are deduced using the experimental transmittance and reflectance spectra. Furthermore, a combination of classical models such as Tauc, Urbach, Spitzer-Fan, and Drude models are applied to calculate the optical and optoelectronic parameters and the energy gaps of the prepared nanocomposite thin films. The optical bandgap energy of PMMA-PVA thin film is found to be 4.101 eV. Incorporation of TiO2 NPs into PMMA-PVA polymeric thin films leads to a decrease in the optical bandgap and thus bandgap engineering is possible. Fourier-transform infrared spectroscopy (FTIR) transmittance spectra of thin films are measured and interpreted to identify the vibrational modes. To elucidate the chemical stability, thermogravimetric (TGA) curves are measured. We found that (PMMA-PVA)/TiO2 NPs polymeric thin films are thermally stable below 110 °C enable them to be attractive for a wide range of optical and optoelectronic applications. Full article
(This article belongs to the Special Issue Sol-Gel Method Applied to Crystalline Materials)
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10 pages, 2604 KiB  
Article
Characterization of Bioactive Glass Synthesized by Sol-Gel Process in Hot Water
by Tan Hiep Dang, Thi Hoa Bui, Elena V. Guseva, Anh Tuan Ta, Anh Tien Nguyen, Thi Trong Hoa Hoang and Xuan Vuong Bui
Crystals 2020, 10(6), 529; https://doi.org/10.3390/cryst10060529 - 21 Jun 2020
Cited by 14 | Viewed by 4248
Abstract
Bioactive glass 70SiO2-30CaO (mol.%) was successfully synthesized by modified sol–gel in hot water without using an acid catalyst. TG-DSC analysis showed that the amorphous glass could be synthesized by sintering the sample at 700 °C for three hours. The N2 [...] Read more.
Bioactive glass 70SiO2-30CaO (mol.%) was successfully synthesized by modified sol–gel in hot water without using an acid catalyst. TG-DSC analysis showed that the amorphous glass could be synthesized by sintering the sample at 700 °C for three hours. The N2 adsorption/desorption and TEM investigations highlighted that the synthetic glass had a mesoporous structure, consisting of spherical particles with sizes in the range of 11–20 nm. The specific surface area, pore volume, and average pore diameter of synthetic glass were 150.13 m2/g, 0.37 cm3/g, and 11.84 nm, respectively. Moreover, synthetic bioactive glass presented interesting bioactivity and good biocompatibility after in vitro experiments in simulated body fluid (SBF) and in cellular medium. Full article
(This article belongs to the Special Issue Sol-Gel Method Applied to Crystalline Materials)
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11 pages, 3020 KiB  
Article
Effect of the Zr-Substitution on the Structural and Electrical Properties of LaFeO3: XRD, Raman Scattering, SEM, and Impedance Spectroscopy Study
by Djoko Triyono, Ismi Purnamasari and Rifqi Almusawi Rafsanjani
Crystals 2020, 10(5), 399; https://doi.org/10.3390/cryst10050399 - 15 May 2020
Cited by 11 | Viewed by 3406
Abstract
The LaFe1−xZrxO3 (x = 0.01, 0.05) ceramics were prepared by sol-gel and annealing method and studied by XRD, Raman scattering analysis, SEM, and impedance spectroscopy method. The crystal structure and phonon characteristics analysis revealed that the crystal structure [...] Read more.
The LaFe1−xZrxO3 (x = 0.01, 0.05) ceramics were prepared by sol-gel and annealing method and studied by XRD, Raman scattering analysis, SEM, and impedance spectroscopy method. The crystal structure and phonon characteristics analysis revealed that the crystal structure tends to preserve its ideal orthorhombic structure, following the increase in driving force of the Fe/ZrO6 octahedral tilting. The frequency-dependent dielectric parameters at each temperature decreased with increasing Zr content. The temperature dependence dielectric relaxation and dc conduction mechanism satisfied the Arrhenius law and increased with increasing Zr content. The activation energy ranged from 0.30 to 0.50 eV and was similar in the relaxation and conduction mechanisms, indicating that both transport mechanisms were based on a similar mechanism. Full article
(This article belongs to the Special Issue Sol-Gel Method Applied to Crystalline Materials)
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9 pages, 1591 KiB  
Article
Sol-Gel Coatings for Subaquatic Self-Cleaning Windows
by Andrew I. M. Greer, David Moodie, Graham Kerr and Nikolaj Gadegaard
Crystals 2020, 10(5), 375; https://doi.org/10.3390/cryst10050375 - 7 May 2020
Cited by 1 | Viewed by 2755
Abstract
Self-cleaning windows are well known for their ability to function with airborne pollutants, but there is a growing industry for semi-permanent subaquatic optical devices, where the performance of such windows should be considered. Here sol-gel technology is explored as a means of producing [...] Read more.
Self-cleaning windows are well known for their ability to function with airborne pollutants, but there is a growing industry for semi-permanent subaquatic optical devices, where the performance of such windows should be considered. Here sol-gel technology is explored as a means of producing self-cleaning, subaquatic, sapphire windows. We demonstrate removal of marine bacteria and, in the worst-case contamination scenario, dead North Sea crude oil (API 35). This greasy contaminant was smeared across the windows to effectively reduce optical transmission strength to just 54%. The titania-based sol-gel-coated windows can restore transmission to within 10% of the clean value in less than one day, unlike standard sapphire windows, which lose 68% transmission following contamination and aquatic submergence over the same duration. A range of theories to enhance the self-cleaning performance of the sol-gel coating were explored, but none of the tested variables were able to provide any enhancement for subaquatic performance. Full article
(This article belongs to the Special Issue Sol-Gel Method Applied to Crystalline Materials)
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