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  • 1
    Online Resource
    Online Resource
    Physicochemical and Morphological Properties of Hybrid Films Containing Silver-Based Silica Materials Deposited on Glass Substrates
    MDPI AG ; 2022
    In:  Coatings Vol. 12, No. 2 ( 2022-02-13), p. 242-
    Details
    In: Coatings, MDPI AG, Vol. 12, No. 2 ( 2022-02-13), p. 242-
    Abstract: The main goal of this study was to present a facile and inexpensive approach for the preparation of hybrid coatings by the deposition under ambient air conditions of silver-based silica materials on glass substrates, which can be used to improve solar cells’ performance. The silica materials containing silver nanoparticles (AgNPs) were synthesized by the hydrolytic condensation of tetraethylorthosilicate (TEOS), triethoxymethylsilane (MTES), and trimethoxyhexadecylsilane (HDTMES), under acidic conditions, at room temperature (25 ± 2 °C). The silver nitrate solution (AgNO3, 0.1 wt. %) was used as a source of Ag+ ions. The final samples were investigated through Fourier Transform Infrared Spectroscopy–Attenuated Total Reflectance (FTIR–ATR), Transmission Electron Microscopy equipped with energy dispersive X–ray (TEM–EDX), UV–Vis spectroscopy, Atomic Force Microscopy (AFM), and Raman Spectroscopy (RS). The TEM images confirmed the formation of AgNPs and were found to be around 3 nm. It was observed that AgNPs were embedded in the silica matrix. EDX also confirmed the presence of the resulting AgNPs within the silica material. AFM images demonstrated that the morphology of the hybrid films’ surfaces can be changed as a function of sol–gel composition. RS analysis indicated that silanol groups were significantly present on the silver-based silica film surface. The UV–Vis spectra revealed that the hybrid coatings presented a reflectance of ~8%, at 550 nm. This study will enhance the value of nanocoating technology in optoelectronics, particularly in the development of nanostructures that improve the performance in thin-film solar cells.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings12020242
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
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  • 2
    Online Resource
    Online Resource
    Investigation of Hybrid Films Based on Fluorinated Silica Materials Prepared by Sol–Gel Processing
    MDPI AG ; 2022
    In:  Coatings Vol. 12, No. 10 ( 2022-10-20), p. 1595-
    Details
    In: Coatings, MDPI AG, Vol. 12, No. 10 ( 2022-10-20), p. 1595-
    Abstract: In this research, fluorinated silica materials were prepared through sol–gel processing with tetraethylorthosilicate (TEOS), triethoxymethylsilane (MTES), and trimethoxyhexadecylsilane (HDTMES), using a fluorinated solution (FS) under acidic medium. The fluorinated solution (FS) was obtained by diluting the perfluorooctanoic acid (PFOA) in 2-propanol. These fluorinated sol–gel silica materials were placed on the glass surfaces in order to achieve the antireflective and hydrophobic fluorinated hybrid films. The structure and surface properties of the final samples were investigated by Fourier transform infrared spectroscopy (FTIR), ultraviolet/visible spectroscopy, thermogravimetric analysis (TGA), atomic force microscopy (AFM), and contact angle (CA) determinations. FTIR spectra demonstrated the presence of a silica network modified with alkyl and fluoroalkyl groups. Thermal analysis showed that the fluorinated sol–gel silica materials prepared with HDTMES have a good thermostability in comparison with other samples. Ultraviolet/visible spectra indicated that the fluorinated hybrid films present a reflectance of ~9.5%, measured at 550 nm. The water contact angle analysis found that the wettability of fluorinated hybrid films was changed from hydrophilic (64°) to hydrophobic (~104°). These hybrid films based on fluorinated sol–gel silica materials can be useful in various electronics and optics fields.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings12101595
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
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  • 3
    Online Resource
    Online Resource
    Characterization of Two Types of Polylactic Acid Coating Loaded with Gentamicin Sulphate Deposed on AZ31 Alloy
    MDPI AG ; 2023
    In:  Coatings Vol. 13, No. 6 ( 2023-06-15), p. 1105-
    Details
    In: Coatings, MDPI AG, Vol. 13, No. 6 ( 2023-06-15), p. 1105-
    Abstract: This paper compares two types of polylactic acid (PLA) coating on AZ31 alloy obtained by dip coating and electrospinning. Both types of coating were loaded with gentamicin sulphate (GS) and the drug-loading efficiency and release were assessed. A higher encapsulation and release efficiency of GS was seen for dip coating (73% and 49.53%, respectively) compared to nanofiber coating (65% and 12.37%, respectively). Furthermore, the antibacterial effect of the samples with and without GS was assessed using Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, showing that the samples with the drug encapsulated are more resistant to bacteria than the other samples. The electrochemical data reveal a higher stability in the SBF of the surface obtained by dipping than that obtained by electrospinning. The PLA coating shows a porosity of 46% for the sample obtained through dip coating and 32% for nanofibers, which is in accordance with the BET analysis results. Moreover, a higher adhesion strength was obtained for AZ31-PLA-dip (4.99 MPa) than for the AZ31-PLA-nanofibers (1.66 MPa). All samples were structurally, morphologically, and topographically characterized.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings13061105
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
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  • 4
    Online Resource
    Online Resource
    Effect of Modified Silica Materials on Polyvinyl Chloride (PVC) Substrates to Obtain Transparent and Hydrophobic Hybrid Coatings
    MDPI AG ; 2021
    In:  Applied Sciences Vol. 11, No. 22 ( 2021-11-22), p. 11044-
    Details
    In: Applied Sciences, MDPI AG, Vol. 11, No. 22 ( 2021-11-22), p. 11044-
    Abstract: In this research, we report a simple and inexpensive way to prepare transparent and hydrophobic hybrid coatings through deposition of different silica materials on polyvinyl chloride (PVC) substrates. The silica materials were prepared using an acid-catalyzed sol–gel method at room temperature (25 ± 2 °C), using alkoxysilanes: tetraethoxysilane (TEOS), as the silica source, and ethoxydimethylvinylsilane (DMVES), triethoxyoctylsilane (OTES), and trimethoxyhexadecylsilane (HDTMES), as modifier agents. The obtained materials were characterized (either as powders or as thin films) by Fourier-transform infrared spectroscopy (FTIR), UV/Vis spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), atomic force microscopy (AFM), spectroscopic ellipsometry (SE), and water contact-angle measurements. UV/Vis spectra showed that the PVC substrate coated with the silica material containing TEOS/DMVES/OTES had a transmittance of about 90% in the wavelength range of 650–780 nm. The water contact angles increased from 83° for uncoated PVC substrate to ~94° for PVC substrates coated with the sol–gel silica materials. These PVC films with hybrid silica coatings can be used as the materials for outdoor applications, such as energy-generating solar panel window blinds or PVC clear Windmaster outdoor blinds.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    URL: Article
    DOI: 10.3390/app112211044
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2704225-X
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  • 5
    Online Resource
    Online Resource
    Preparation and Characterization of Some Sol-Gel Modified Silica Coatings Deposited on Polyvinyl Chloride (PVC) Substrates
    MDPI AG ; 2020
    In:  Coatings Vol. 11, No. 1 ( 2020-12-24), p. 11-
    Details
    In: Coatings, MDPI AG, Vol. 11, No. 1 ( 2020-12-24), p. 11-
    Abstract: Transparent and antireflective coatings were prepared by deposition of modified silica materials onto polyvinyl chloride (PVC) substrates. These materials were obtained by the sol-gel route in acidic medium, at room temperature (25 °C), using different alkoxysilanes with various functional groups (methyl, vinyl, octyl or hexadecyl). Physicochemical and microstructural properties of resulted silica materials and of thin coatings were investigated through Fourier Transforms Infrared Spectroscopy (FTIR), UV-Vis spectroscopy, Thermal Gravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Atomic Force Microscopy (AFM) and ellipsometric measurements. Wetting behaviors of the silica coatings were evaluated by measurement of static contact angle against water. FTIR spectra of materials confirmed the high degree of cross-linking that result from the formation of the inorganic backbone through the hydrolysis and polycondensation reactions together with the formation of the organic network. These sol-gel silica coatings showed a reduction in the reflectance (10%) compared with uncoated PVC substrate. AFM reveals that the films are uniform, and adherent to the substrate, but their morphology is strongly influenced by the chemical composition of the coating matrices. These silica coatings can be useful for potential electronic and optical devices.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings11010011
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
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  • 6
    Online Resource
    Online Resource
    Hybrid Organic-Inorganic Materials Used to Improve the Environment and Human Health
    MDPI AG ; 2022
    In:  Crystals Vol. 12, No. 9 ( 2022-09-07), p. 1273-
    Details
    In: Crystals, MDPI AG, Vol. 12, No. 9 ( 2022-09-07), p. 1273-
    Abstract: The Special Issue on “Hybrid Organic-Inorganic Materials Used to Improve the Environment and Human Health” is a collection of 11 original articles (including one communication paper) dedicated to theoretical and experimental research works providing new insights and practical findings in the fields of the environmental protection and human health—related topics [...]
    Type of Medium: Online Resource
    ISSN: 2073-4352
    URL: Article
    DOI: 10.3390/cryst12091273
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661516-2
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  • 7
    Online Resource
    Online Resource
    Modeling the Properties of Curcumin Derivatives in Relation to the Architecture of the Siloxane Host Matrices
    MDPI AG ; 2021
    In:  Materials Vol. 15, No. 1 ( 2021-12-30), p. 267-
    Details
    In: Materials, MDPI AG, Vol. 15, No. 1 ( 2021-12-30), p. 267-
    Abstract: Research in the field of natural dyes has constantly focused on methods of conditioning curcumin and diversifying their fields of use. In this study, hybrid materials were obtained from modified silica structures, as host matrices, in which curcumin dyes were embedded. The influence of the silica network structure on the optical properties and the antimicrobial activity of the hybrid materials was monitored. By modifying the ratio between phenyltriethoxysilane:diphenyldimethoxysilane (PTES:DPDMES), it was possible to evaluate the influence the organosilane network modifiers had on the morphostructural characteristics of nanocomposites. The nanosols were obtained by the sol–gel method, in acid catalysis. The nanocomposites obtained were deposited as films on a glass support and showed a transmittance value (T measured at 550 nm) of around 90% and reflectance of about 11%, comparable to the properties of the uncovered support. For the coatings deposited on PET (polyethylene terephthalate) films, these properties remained at average values of T550 = 85% and R550 = 11% without significantly modifying the optical properties of the support. The sequestration of the dye in silica networks reduced the antimicrobial activity of the nanocomposites obtained, by comparison to native dyes. Tests performed on Candida albicans fungi showed good results for the two curcumin derivatives embedded in silica networks (11–18 mm) by using the spot inoculation method; in comparison, the alcoholic dye solution has a spot diameter of 20–23 mm. In addition, hybrids with the CA derivative were the most effective (halo diameter of 17–18 mm) in inhibiting the growth of Gram-positive bacteria, compared to the curcumin derivative in alcoholic solution (halo diameter of 21 mm). The results of the study showed that the presence of 20–40% by weight DPDMES in the composition of nanosols is the optimal range for obtaining hybrid films that host curcumin derivatives, with potential uses in the field of optical films or bioactive coatings.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    URL: Article
    DOI: 10.3390/ma15010267
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2487261-1
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  • 8
    Online Resource
    Online Resource
    Multifunctional Finishing of Cotton Fabric with Curcumin Derivatives Coatings Obtained by Sol–Gel Method
    MDPI AG ; 2023
    In:  Gels Vol. 9, No. 5 ( 2023-04-30), p. 369-
    Details
    In: Gels, MDPI AG, Vol. 9, No. 5 ( 2023-04-30), p. 369-
    Abstract: Textile materials with fluorescent, repellent, or antimicrobial properties are increasingly used in common applications. Obtaining multi-functional coatings is of wide interest, especially for applications related to signaling or to the medical field. In order to increase the performance (color properties, fluorescence lifetime, self-cleaning or antimicrobial properties) of textile materials with special uses, a series of research was carried out regarding the modification of surfaces with nanosols. In this study, coatings with multiple properties were obtained by depositing nanosols on cotton fabrics generated through sol–gel reactions. These multifunctional coatings are hybrid materials in which the host matrix is generated using tetraethylorthosilicate (TEOS) and network modifying organosilanes:dimethoxydimethylsilane (DMDMS) or dimethoxydiphenylsilane (DMDPS) in a 1:1 mass ratio. Two curcumin derivatives were embedded in siloxane matrices, a yellow one (CY) that is identical to bis-demethoxycurcumin (one of the natural constituents in turmeric) and a red dye (CR) that has a N,N-dimethylamino group grafted in position 4 of the dicinnamoylmethane skeleton of curcumin. The nanocomposites obtained by embedding curcumin derivatives in siloxane matrices were deposited on cotton fabric and studied in relation to the dye and the type of host matrix. Fabrics coated with such systems provide a hydrophobic surface, have fluorescent and antimicrobial properties, change color depending on the pH, and therefore can be used in various fields where textiles provide signaling properties, self-cleaning, or antibacterial protection. The coated fabrics maintained their good multifunctional properties even after several washing cycles.
    Type of Medium: Online Resource
    ISSN: 2310-2861
    URL: Article
    DOI: 10.3390/gels9050369
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2813982-3
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  • 9
    Online Resource
    Online Resource
    Influence of Organic-Modified Inorganic Matrices on the Optical Properties of Palygorskite–Curcumin-Type Hybrid Materials
    MDPI AG ; 2022
    In:  Crystals Vol. 12, No. 7 ( 2022-07-20), p. 1005-
    Details
    In: Crystals, MDPI AG, Vol. 12, No. 7 ( 2022-07-20), p. 1005-
    Abstract: Clays are very important from an economic and application point of view, as they are suitable hosts for organic compounds. In order to diversify the fields of application, they are structurally modified by physical or chemical methods with cationic species, and/or different bifunctional compounds, such as organosilanes. In this study, palygorskite was modified with (3-Aminopropyl) triethoxysilane, which was subsequently modified at the amino group by grafting an acetate residue. By using this strategy, two types of host hybrid materials were obtained on which curcumin derivatives were deposited. The composites obtained were structurally characterized and their photophysical properties were investigated in relation to the structure of the host matrices and interactions with curcumin-type visiting species. The hybrid composites have different colors (orange, yellow, pink), depending on the polarity of the inorganic matrices modulated by different organic groups grafted at the surface. Fluorescence emission in the visible range is characterized by the presence of two emission maxima, one belonging to the chromophore and the other influenced by the physical interactions between auxochromes and host matrices. These hybrid materials, compared to other composite structures, are obtained by a simple adsorption process. They are temperature stable in aggressive environments (acid/base) and render the fluorescent properties of dyes redundant, with improved luminescent performance compared to them.
    Type of Medium: Online Resource
    ISSN: 2073-4352
    URL: Article
    DOI: 10.3390/cryst12071005
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661516-2
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  • 10
    Online Resource
    Online Resource
    Optical Behavior of Curcuminoid Hybrid Systems as Coatings Deposited on Polyester Fibers
    MDPI AG ; 2022
    In:  Coatings Vol. 12, No. 2 ( 2022-02-17), p. 271-
    Details
    In: Coatings, MDPI AG, Vol. 12, No. 2 ( 2022-02-17), p. 271-
    Abstract: The recent development of the “eco-friendly” current has brought to the attention of researchers natural dyes that are biodegradable, do not cause allergies and generally have anti-UV protection, and antioxidant and antibacterial properties. In this study, we aimed to obtain hybrid materials of the dye–host matrix type, by using the sol–gel process. The silica network was generated by tetraethylorthosilicates and modified with organic siloxane derivatives: phenyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, dimethoxydimethylsilane and dimethoxydiphenylsilane. The nanocomposites obtained by embedding curcumin in siloxane matrices were deposited on polyester fabric and evaluated for their properties, relative to the type of organic network modifier used. Fabrics covered with curcuminoid hybrid systems provide a hydrophobic surface, have fluorescent properties and a UPF +50, and, therefore, they can be used in various fields where it is necessary for textiles to provide signaling, self-cleaning or protection properties against ultraviolet radiation. The coated textile materials have very good resistance properties after several repeated washing cycles, and maintain the original UV protection factor at high values even after washing or during rubbing tests.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings12020271
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662314-6
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