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10 pages, 5275 KiB

Open AccessCommunication

Low-Temperature Synthesis of Bi₂S₃ Hierarchical Microstructures via Co-Precipitation and Digestive Process in Aqueous Medium

by José Alfonso Carrasco-González, Rebeca Ortega-Amaya, Esteban Díaz-Torres, Manuel A. Pérez-Guzmán and Mauricio Ortega-López

Materials 2024, 17(8), 1818; https://doi.org/10.3390/ma17081818 - 16 Apr 2024

Viewed by 363

Abstract

Bismuth sulfide (Bi₂S₃) nanostructures have gained significant attention in the fields of catalysis, optoelectronics, and biomedicine due to their unique physicochemical properties. This paper introduces a simple and cost-effective method for producing Bi₂S₃ microstructures at low [...] Read more.

Bismuth sulfide (Bi₂S₃) nanostructures have gained significant attention in the fields of catalysis, optoelectronics, and biomedicine due to their unique physicochemical properties. This paper introduces a simple and cost-effective method for producing Bi₂S₃ microstructures at low temperatures (25 and 70 °C). These microstructures are formed by the hierarchical self-assembly of Bi₂S₃ nanoparticles, which are typically 15–40 nm in size. The nanoparticles are synthesized by the co-precipitation of thioglycolic acid, thioacetamide, and bismuth nitrate in water. The study delves into the phase composition and morphological evolution of the microstructures, concerning the chemical composition of the solution and the synthesis temperature. X-ray analysis has confirmed the formation of single-phase bismuthinite Bi₂S₃. The synthesis process generates primary building blocks in the form of 15–40 nm Bi₂S₃ nanocrystals, which then go through a hierarchical self-assembly process to produce a range of micrometer-sized structures. A scanning electron microscopy examination revealed that the primary nanoparticles self-assemble into quasi-1D worm-like nanostructures, which then self-assemble to create sponge-shaped microstructures. These structures subsequently self-organize and refine into either flower- or dandelion-like microstructures, mostly depending on the synthesis temperature and the chemistry of the digestion medium. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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20 pages, 13732 KiB

Open AccessArticle

Electrospun PCL Wires Loaded with Vancomycin on Zirconium Substrate

by Ramona-Daniela Radu (Dusman), Manuela Elena Voicu, Mariana Prodana, Ioana Demetrescu, Valentina Anuta and Doina Draganescu

Materials 2023, 16(22), 7237; https://doi.org/10.3390/ma16227237 - 20 Nov 2023

Viewed by 758

Abstract

The current study presents research about electrodeposition in relation to electrospinning PCL wires on a Zr substrate and loading the coating with vancomycin. The structural composition of the coatings was investigated via FT-IR analysis. The morphology evaluated using scanning electron microscopy coupled with [...] Read more.

The current study presents research about electrodeposition in relation to electrospinning PCL wires on a Zr substrate and loading the coating with vancomycin. The structural composition of the coatings was investigated via FT-IR analysis. The morphology evaluated using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, for the composition (SEM-EDS), evidenced the presence of the polymer wires, with and without drug vancomycin loading. The wettability of the coatings was evaluated from the hydrophobic–hydrophilic point of view, and the characterization was completed with mechanical and electrochemical tests. All the electrochemical tests performed in simulated body fluid highlighted that PCL represents a barrier against corrosion processes. The quantitative method to evaluate the loading efficiency shows that almost 80% of the total loaded vancomycin is released within 144 h; after the initial burst at 24 h, a steady release of vancomycin is observed over 7 days. A kinetic model of the drug release was also constructed. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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16 pages, 7919 KiB

Open AccessArticle

Advanced Procedure of Simultaneous Electrodeposition from a Natural Deep Eutectic Solvent of a Drug and a Polymer Used to Improve TiZr Alloy Behavior

by Manuela Elena Voicu, Florentina Golgovici, Mariana Prodana, Doina Draganescu and Ioana Demetrescu

Materials 2023, 16(12), 4387; https://doi.org/10.3390/ma16124387 - 14 Jun 2023

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Abstract

This paper presents research about the embedding and release of gentamicin from an electrochemical deposition of polypyrrole from ionic liquids such as choline chloride on TiZr bioalloy. The electrodeposited films were morphologically investigated using scanning electron microscopy (SEM) with an EDX module, and [...] Read more.

This paper presents research about the embedding and release of gentamicin from an electrochemical deposition of polypyrrole from ionic liquids such as choline chloride on TiZr bioalloy. The electrodeposited films were morphologically investigated using scanning electron microscopy (SEM) with an EDX module, and polypyrrole and gentamicin were both identified using structural FT-IR analysis. The film’s characterization was completed with an evaluation of hydrophilic–hydrophobic balance, with electrochemical stability measurements in PBS and with antibacterial inhibition. A decrease in the value of the contact angle was observed from 47.06° in the case of the uncoated sample to 8.63° in the case of the sample covered with PPy and GS. Additionally, an improvement in the anticorrosive properties of the coating was observed by increasing the efficiency to 87.23% in the case of TiZr–PPy–GS. A kinetic study of drug release was performed as well. The drug molecule might be provided by the PPy–GS coatings for up to 144 h. The highest amount released was calculated to be 90% of the entire drug reservoir capacity, demonstrating the effectiveness of the coatings. A non-Fickian behavior was established as a mechanism for the release profiles of the gentamicin from the polymer layer. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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17 pages, 6183 KiB

Open AccessArticle

Drag Reduction Technology of Water Flow on Microstructured Surfaces: A Novel Perspective from Vortex Distributions and Densities

by Chunye Liu, Wene Wang, Xiaotao Hu and Fulai Liu

Materials 2023, 16(5), 1838; https://doi.org/10.3390/ma16051838 - 23 Feb 2023

Viewed by 1188

Abstract

Revealing the turbulent drag reduction mechanism of water flow on microstructured surfaces is beneficial to controlling and using this technology to reduce turbulence losses and save energy during water transportation. Two microstructured samples, including a superhydrophobic and a riblet surface, were fabricated near [...] Read more.

Revealing the turbulent drag reduction mechanism of water flow on microstructured surfaces is beneficial to controlling and using this technology to reduce turbulence losses and save energy during water transportation. Two microstructured samples, including a superhydrophobic and a riblet surface, were fabricated near which the water flow velocity, and the Reynolds shear stress and vortex distribution were investigated using a particle image velocimetry. The dimensionless velocity was introduced to simplify the Ω vortex method. The definition of vortex density in water flow was proposed to quantify the distribution of different strength vortices. Results showed that the velocity of the superhydrophobic surface (SHS) was higher compared with the riblet surface (RS), while the Reynolds shear stress was small. The vortices on microstructured surfaces were weakened within 0.2 times that of water depth when identified by the improved Ω_M method. Meanwhile, the vortex density of weak vortices on microstructured surfaces increased, while the vortex density of strong vortices decreased, proving that the reduction mechanism of turbulence resistance on microstructured surfaces was to suppress the development of vortices. When the Reynolds number ranged from 85,900 to 137,440, the drag reduction impact of the superhydrophobic surface was the best, and the drag reduction rate was 9.48%. The reduction mechanism of turbulence resistance on microstructured surfaces was revealed from a novel perspective of vortex distributions and densities. Research on the structure of water flow near the microstructured surface can promote the drag reduction application in the water field. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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13 pages, 3890 KiB

Open AccessArticle

Synthesis Optimization of BaGdF₅:x%Tb³⁺ Nanophosphors for Tunable Particle Size

by Vladimir Polyakov, Zaira Gadzhimagomedova, Daria Kirsanova and Alexander Soldatov

Materials 2022, 15(23), 8559; https://doi.org/10.3390/ma15238559 - 01 Dec 2022

Cited by 1 | Viewed by 977

Abstract

X-ray photodynamic therapy (XPDT) is aimed at the treatment of deep-located malignant tumors thanks to the high penetration depth of X-rays. In XPDT therapy, it is necessary to use materials that effectively absorb X-rays and convert them into visible radiation-nanophosphors. Rare-earth elements, fluorides, [...] Read more.

X-ray photodynamic therapy (XPDT) is aimed at the treatment of deep-located malignant tumors thanks to the high penetration depth of X-rays. In XPDT therapy, it is necessary to use materials that effectively absorb X-rays and convert them into visible radiation-nanophosphors. Rare-earth elements, fluorides, in particular, doped BaGdF₅, are known to serve as efficient nanophosphor. On the other hand, the particle size of nanophosphors has a crucial impact on biodistribution, cell uptake, and cytotoxicity. In this work, we investigated various Tb:Gd ratios in the range from 0.1 to 0.5 and optimized the terbium content to achieve the maximum luminescence under X-ray excitation. The effect of temperature, composition of the ethylene glycol/water solvent, and the synthesis technique (solvothermal and microwave) on the size of the nanophosphors was explored. It was found that the synthesis techniques and the solvent composition had the greatest influence on the averaged particle size. By varying these two parameters, it is possible to tune the size of the nanophosphor particles, which make them suitable for biomedical applications. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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19 pages, 4113 KiB

Open AccessArticle

Antibacterial and Photocatalytic Coatings Based on Cu-Doped ZnO Nanoparticles into Microcellulose Matrix

by Mariana Bușilă, Viorica Mușat, Rodica Dinică, Dana Tutunaru, Aida Pantazi, Dorel Dorobantu, Daniela C. Culiță and Marius Enăchescu

Materials 2022, 15(21), 7656; https://doi.org/10.3390/ma15217656 - 31 Oct 2022

Cited by 4 | Viewed by 1466

Abstract

The paper presents a successful, simple method for the preparation and deposition of new hybrid Cu-doped ZnO/microcellulose coatings on textile fibers, directly from cellulose aqueous solution. The morphological, compositional, and structural properties of the obtained materials were investigated using different characterization methods, such [...] Read more.

The paper presents a successful, simple method for the preparation and deposition of new hybrid Cu-doped ZnO/microcellulose coatings on textile fibers, directly from cellulose aqueous solution. The morphological, compositional, and structural properties of the obtained materials were investigated using different characterization methods, such as SEM-EDX, XRD, Raman and FTIR, as well as BET surface area measurements. The successful doping of ZnO NPs with Cu was confirmed by the EDX and Raman analysis. As a result of Cu doping, the hybrid NPs experienced a phase change from ZnO to (Zn_0.9Cu_0.1)O, as shown by the XRD results. All the hybrid NPs exhibited a high degree of crystallinity, as revealed by the very sharp reflections in XRD patterns and suggested also by the Raman results. The evaluation of the very low copper-doping (0.1–1 at.%) effect has shown different behavior trends of the hybrid coatings compared with the starting oxide NPs, for MB and MO photodegradation. Continuous increases up to 92% and 60% for MB and MO degradation, respectively, were obtained at maximum 1 at.%-Cu doping coatings. Strong antibacterial activity against S. aureus and E. coli were observed. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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11 pages, 3703 KiB

Open AccessArticle

The Effects of Precursors on the Morphology and Chemical Mechanical Polishing Performance of Ceria-Based Abrasives

by Yuanyuan Zheng, Ning Wang, Zongyu Feng, Xianmin Tan, Zhenyu Zhang, Huiqing Han and Xiaowei Huang

Materials 2022, 15(21), 7525; https://doi.org/10.3390/ma15217525 - 27 Oct 2022

Cited by 3 | Viewed by 1676

Abstract

Ceria-based abrasives are widely used in precision chemical mechanical polishing (CMP) fields, such as thin film transistor liquid crystal display (TFT-LCD) glass substrates and integrated circuits, because of their excellent physicochemical properties. Rare earth carbonates, as precursors of ceria-based abrasives, directly affect the [...] Read more.

Ceria-based abrasives are widely used in precision chemical mechanical polishing (CMP) fields, such as thin film transistor liquid crystal display (TFT-LCD) glass substrates and integrated circuits, because of their excellent physicochemical properties. Rare earth carbonates, as precursors of ceria-based abrasives, directly affect the morphology of ceria-based abrasives, which, in turn, affects the material removal rate (MRR) and the surface roughness (R_a) after polishing. Herein, rare earth carbonates with different morphologies were obtained by adjusting reaction parameters during precipitation, including flake, spindle, and spheroid. Moreover, the phase of precursors was analyzed, and the evolution process of morphology from precursors to ceria-based abrasives was investigated. Furthermore, the effect of precursors on the polishing performance of ceria-based abrasives was explored. The results show that the primary particles of ceria-based abrasives are near-spherical, but the morphology and dispersion of the secondary particles are obviously inherited from precursors. Among them, near-spherical ceria-based abrasives prepared by nearly monodisperse near-spherical precursors show better uniformity and higher dispersion, and they not only achieve the lowest R_a but also obtain a higher MRR of 555 nm/min (9 wt.%) for polishing TFT-LCD glass substrates. The result is significant for the further optimization and application of high-performance ceria-based abrasives. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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18 pages, 3549 KiB

Open AccessArticle

Corrosion Testing of CrN_x-Coated 310 H Stainless Steel under Simulated Supercritical Water Conditions

by Aurelia Elena Tudose, Florentina Golgovici, Alexandru Anghel, Manuela Fulger and Ioana Demetrescu

Materials 2022, 15(16), 5489; https://doi.org/10.3390/ma15165489 - 10 Aug 2022

Cited by 4 | Viewed by 1384

Abstract

The paper’s aim is the assessment of corrosion behaviour of a CrN_x-coated 310 H stainless steel under simulated supercritical water conditions (550 °C and 25 MPa) for up to 2160 h. The CrN_x coating was obtained by the thermionic vacuum [...] Read more.

The paper’s aim is the assessment of corrosion behaviour of a CrN_x-coated 310 H stainless steel under simulated supercritical water conditions (550 °C and 25 MPa) for up to 2160 h. The CrN_x coating was obtained by the thermionic vacuum arc (TVA) method. The oxides grown on this coating were characterized using metallographic and gravimetric analysis, SEM with EDS, and grazing incidence X-ray diffraction (GIXRD). A diffusion mechanism drives oxidation kinetics because it follows a parabolic law. By XRD analysis, the presence of Cr₂O₃ and Fe₃O₄ on the surface of the autoclaved CrN_x-coated 310 H samples were highlighted. Corrosion susceptibility assessment was performed by electrochemical impedance spectroscopy (EIS) and linear potentiodynamic polarization. EIS impedance spectra show the presence of two capacitive semicircles in the Nyquist diagram, highlighting both the presence of the CrN_x coating and the oxide film formed during autoclaving on the 310 H stainless steel. Very low corrosion rates, with values up to 11 nm × year⁻¹, obtained in the case of autoclaved for 2160 h, CrN_x-coated samples indicated that the oxides formed on these samples are protective and provide better corrosion resistance. The determination of micro hardness Vickers completed the above investigation. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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14 pages, 3288 KiB

Open AccessArticle

Optimization of the Growth Process of Double Perovskite Pr_2−δNi_1−xMn_1+xO_6−y Epitaxial Thin Films by RF Sputtering

by Mónica Bernal-Salamanca, Lluis Balcells, Zorica Konstantinović, Alberto Pomar, Benjamín Martínez and Carlos Frontera

Materials 2022, 15(14), 5046; https://doi.org/10.3390/ma15145046 - 20 Jul 2022

Cited by 4 | Viewed by 1186

Abstract

Epitaxial thin films of Pr_2−δNi_1−xMn_1+xO_6−y (PNMO) double perovskite were grown on (001)-oriented SrTiO₃ substrates by RF magnetron sputtering. The influence of the growth parameters (oxygen pressure, substrate temperature, and annealing treatments) on the structural, magnetic [...] Read more.

Epitaxial thin films of Pr_2−δNi_1−xMn_1+xO_6−y (PNMO) double perovskite were grown on (001)-oriented SrTiO₃ substrates by RF magnetron sputtering. The influence of the growth parameters (oxygen pressure, substrate temperature, and annealing treatments) on the structural, magnetic and transport properties, and stoichiometry of the films was thoroughly investigated. It is found that high-quality epitaxial, insulating, and ferromagnetic PNMO thin films can only be obtained in a narrow deposition parameter window. It is shown that a careful selection of the growth conditions allows for obtaining a high degree of Ni/Mn cation ordering, which is reflected in the values of the Curie temperature, T_C, and saturation magnetization, M_S, which are very close to those of bulk material. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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16 pages, 3575 KiB

Open AccessArticle

Simultaneously Embedding Indomethacin and Electrodeposition of Polypyrrole on Various CoCr Alloys from Ionic Liquids

by Florentina Golgovici, Florentina Gina Ionascu, Mariana Prodana and Ioana Demetrescu

Materials 2022, 15(13), 4714; https://doi.org/10.3390/ma15134714 - 05 Jul 2022

Cited by 1 | Viewed by 1359

Abstract

The aim of the present investigation is the electrochemical deposition of polypyrrole films from choline chloride-based ionic liquids at various potential, period times and simultaneously an indomethacin embedding and release. The electrodeposition films were performed on CoCr commercial type Wirobond C (WBC) and, [...] Read more.

The aim of the present investigation is the electrochemical deposition of polypyrrole films from choline chloride-based ionic liquids at various potential, period times and simultaneously an indomethacin embedding and release. The electrodeposition films were performed on CoCr commercial type Wirobond C (WBC) and, Heraenium CE (Hera) using as electroprocedures for deposition cyclic voltammetry and chronoamperometry. The morphology of obtained films was investigated using scanning electron microscopy (SEM). An FT-IR investigation of CoCr alloys before and after electrodeposition was able to identify the presence of polymer and drug. The research included an evaluation of the hydrophilic character of all studied samples and their electrochemical characterization in Tanni Zuchi artificial saliva. In the electrochemical study, the following methods have been used: open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization. Indomethacin release from the polymeric film was determined using UV-VIS spectra. Based on Fick’s law of diffusion and indomethacin release profile, a kinetic law for release was established and discussed. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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Review

Jump to: Research

48 pages, 1831 KiB

Open AccessReview

Organic and Biogenic Nanocarriers as Bio-Friendly Systems for Bioactive Compounds’ Delivery: State-of-the Art and Challenges

by Sanja M. Petrovic and Marcela-Elisabeta Barbinta-Patrascu

Materials 2023, 16(24), 7550; https://doi.org/10.3390/ma16247550 - 07 Dec 2023

Cited by 4 | Viewed by 1697

Abstract

“Green” strategies to build up novel organic nanocarriers with bioperformance are modern trends in nanotechnology. In this way, the valorization of bio-wastes and the use of living systems to develop multifunctional organic and biogenic nanocarriers (OBNs) have revolutionized the nanotechnological and biomedical fields. [...] Read more.

“Green” strategies to build up novel organic nanocarriers with bioperformance are modern trends in nanotechnology. In this way, the valorization of bio-wastes and the use of living systems to develop multifunctional organic and biogenic nanocarriers (OBNs) have revolutionized the nanotechnological and biomedical fields. This paper is a comprehensive review related to OBNs for bioactives’ delivery, providing an overview of the reports on the past two decades. In the first part, several classes of bioactive compounds and their therapeutic role are briefly presented. A broad section is dedicated to the main categories of organic and biogenic nanocarriers. The major challenges regarding the eco-design and the fate of OBNs are suggested to overcome some toxicity-related drawbacks. Future directions and opportunities, and finding “green” solutions for solving the problems related to nanocarriers, are outlined in the final of this paper. We believe that through this review, we will capture the attention of the readers and will open new perspectives for new solutions/ideas for the discovery of more efficient and “green” ways in developing novel bioperformant nanocarriers for transporting bioactive agents. Full article

(This article belongs to the Special Issue Advanced Nanomaterials: Synthesis, Characterization and Applications)

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