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Nanomaterials, Volume 14, Issue 5 (March-1 2024) – 94 articles

Cover Story (view full-size image): Integrated optical isolators are essential components for photonic integrated chips, yet their development on GaAs-on-insulator platforms has been limited. Two TM mode optical isolators on GaAs-on-insulator platforms were simulated and designed, utilizing an asymmetric MZI type. These isolators feature compact waveguide sizes of only 174.53 μm while achieving impressive isolation of 35 dB and bandwidth exceeding 70 nm with a low loss below 3 dB. Additionally, low-loss MMI couplers tailored to different magneto-optical waveguide structures were developed. The robustness exhibited by these devices positions them with promising prospects in nonlinear integrated photonic applications. View this paper
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14 pages, 3105 KiB  
Article
Multi-Layer Palladium Diselenide as a Contact Material for Two-Dimensional Tungsten Diselenide Field-Effect Transistors
by Gennadiy Murastov, Muhammad Awais Aslam, Simon Leitner, Vadym Tkachuk, Iva Plutnarová, Egon Pavlica, Raul D. Rodriguez, Zdenek Sofer and Aleksandar Matković
Nanomaterials 2024, 14(5), 481; https://doi.org/10.3390/nano14050481 - 06 Mar 2024
Viewed by 938
Abstract
Tungsten diselenide (WSe2) has emerged as a promising ambipolar semiconductor material for field-effect transistors (FETs) due to its unique electronic properties, including a sizeable band gap, high carrier mobility, and remarkable on–off ratio. However, engineering the contacts to WSe2 [...] Read more.
Tungsten diselenide (WSe2) has emerged as a promising ambipolar semiconductor material for field-effect transistors (FETs) due to its unique electronic properties, including a sizeable band gap, high carrier mobility, and remarkable on–off ratio. However, engineering the contacts to WSe2 remains an issue, and high contact barriers prevent the utilization of the full performance in electronic applications. Furthermore, it could be possible to tune the contacts to WSe2 for effective electron or hole injection and consequently pin the threshold voltage to either conduction or valence band. This would be the way to achieve complementary metal–oxide–semiconductor devices without doping of the channel material.This study investigates the behaviour of two-dimensional WSe2 field-effect transistors with multi-layer palladium diselenide (PdSe2) as a contact material. We demonstrate that PdSe2 contacts favour hole injection while preserving the ambipolar nature of the channel material. This consequently yields high-performance p-type WSe2 devices with PdSe2 van der Waals contacts. Further, we explore the tunability of the contact interface by selective laser alteration of the WSe2 under the contacts, enabling pinning of the threshold voltage to the valence band of WSe2, yielding pure p-type operation of the devices. Full article
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22 pages, 14059 KiB  
Article
Comparative Studies of the Structural and Physicochemical Properties of the First Fullerene Derivative FD-C60 (Fullerenol) and Second Fullerene Derivate SD-C60 (3HFWC)
by Djuro Koruga, Ivana Stanković, Lidija Matija, Dietmar Kuhn, Bastian Christ, Sofia Dembski, Nenad Jevtić, Jelena Janać, Vladimir Pavlović and Bart De Wever
Nanomaterials 2024, 14(5), 480; https://doi.org/10.3390/nano14050480 - 06 Mar 2024
Viewed by 650
Abstract
In order to maximally reduce the toxicity of fullerenol (the first derivative of C60, FD-C60), and increase its biomedical efficiency, the second derivative SD-C60 (3HFWC, Hyper-Harmonized Hydroxylated Fullerene Water Complex) was created. Several different methods were applied in [...] Read more.
In order to maximally reduce the toxicity of fullerenol (the first derivative of C60, FD-C60), and increase its biomedical efficiency, the second derivative SD-C60 (3HFWC, Hyper-Harmonized Hydroxylated Fullerene Water Complex) was created. Several different methods were applied in the comparative characterization of FD-C60 and SD-C60 with the same OH groups in their core. FD-C60 as an individual structure was about 1.3 nm in size, while SD-C60 as an individual structure was 10–30 nm in size. Based on ten physicochemical methods and techniques, FD-C60 and SD-C60 were found to be two different substances in terms of size, structure, and physicochemical properties; FD-C60, at 100 °C, had endothermic characteristics, while SD-C60, at 133 °C, had exothermic characteristics; FD-C60 did not have water layers, while SD-C60 had water layers; the zeta potential of FD-C60 was −25.85 mV, while it was −43.29 mV for SD-C60. SD-C60 is a promising substance for use in cosmetics and pharmaceuticals. Full article
(This article belongs to the Special Issue Functional Nanomaterials for Theranostic Applications)
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14 pages, 3820 KiB  
Article
Regioselectively Carboxylated Cellulose Nanofibril Models from Dissolving Pulp: C6 via TEMPO Oxidation and C2,C3 via Periodate–Chlorite Oxidation
by Mengzhe Guo, James D. Ede, Christie M. Sayes, Jo Anne Shatkin, Nicole Stark and You-Lo Hsieh
Nanomaterials 2024, 14(5), 479; https://doi.org/10.3390/nano14050479 - 06 Mar 2024
Cited by 1 | Viewed by 604
Abstract
Regioselective C6 and C2,C3 carboxylated cellulose nanofibrils (CNFs) have been robustly generated from dissolving pulp, a readily available source of unmodified cellulose, via stoichiometrically optimized 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO)-mediated and sequential sodium periodate-sodium chlorite (PC) oxidation coupled with high-speed blending. Both regioselectively optimized carboxylated CNF [...] Read more.
Regioselective C6 and C2,C3 carboxylated cellulose nanofibrils (CNFs) have been robustly generated from dissolving pulp, a readily available source of unmodified cellulose, via stoichiometrically optimized 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO)-mediated and sequential sodium periodate-sodium chlorite (PC) oxidation coupled with high-speed blending. Both regioselectively optimized carboxylated CNF series possess the widest ranges of comparable charges (0.72–1.48 mmol/g for T-CNFs vs. 0.72–1.10 mmol/g for PC-CNFs), but similar ranges of thickness (1.3–2.4 nm for T-CNF, 1.8–2.7 nm PC-CNF), widths (4.6–6.6 nm T-CNF, 5.5–5.9 nm PC-CNF), and lengths (254–481 nm T-CNF, 247–442 nm PC-CNF). TEMPO-mediated oxidation is milder and one-pot, thus more time and process efficient, whereas the sequential periodate–chlorite oxidation produces C2,C3 dialdehyde intermediates that are amenable to further chemical functionalization or post-reactions. These two well-characterized regioselectively carboxylated CNF series represent coherent cellulose nanomaterial models from a single woody source and have served as references for their safety study toward the development of a safer-by-design substance evaluation tool. Full article
(This article belongs to the Special Issue From Biomass to Nanomaterials)
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11 pages, 6074 KiB  
Article
Ultra-Thin Ion Exchange Membranes by Low Ionomer Blending for Energy Harvesting
by Jaehoon Jung, Soyeong Choi, Ilsuk Kang and Kiwoon Choi
Nanomaterials 2024, 14(5), 478; https://doi.org/10.3390/nano14050478 - 06 Mar 2024
Viewed by 680
Abstract
Exploring the utilization of ion exchange membranes (IEMs) in salinity gradient energy harvesting, a technique that capitalizes on the salinity difference between seawater and freshwater to generate electricity, this study focuses on optimizing PVDF to Nafion ratios to create ultra-thin membranes. Specifically, our [...] Read more.
Exploring the utilization of ion exchange membranes (IEMs) in salinity gradient energy harvesting, a technique that capitalizes on the salinity difference between seawater and freshwater to generate electricity, this study focuses on optimizing PVDF to Nafion ratios to create ultra-thin membranes. Specifically, our investigation aligns with applications such as reverse electrodialysis (RED), where IEMs facilitate selective ion transport across salinity gradients. We demonstrate that membranes with reduced Nafion content, particularly the 50:50 PVDF:Nafion blend, retain high permselectivity comparable to those with higher Nafion content. This challenges traditional understandings of membrane design, highlighting a balance between thinness and durability for energy efficiency. Voltage–current analyses reveal that, despite lower conductivity, the 50:50 blend shows superior short-circuit current density under salinity gradient conditions. This is attributed to effective ion diffusion facilitated by the blend’s unique microstructure. These findings suggest that blended membranes are not only cost-effective but also exhibit enhanced performance for energy harvesting, making them promising candidates for sustainable energy solutions. Furthermore, these findings will pave the way for advances in membrane technology, offering new insights into the design and application of ion exchange membranes in renewable energy. Full article
(This article belongs to the Special Issue Nanomaterials for Energy Conversion and Storage)
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14 pages, 3143 KiB  
Article
LDH/MXene Synergistic Carrier Separation Effects to Improve the Photoelectric Catalytic Activities of Bi2WO6 Nanosheet Arrays
by Yuting Wang, Runhua Li, Jiaying Zhang, Liming Liu, Weiwei Huang and Yajun Wang
Nanomaterials 2024, 14(5), 477; https://doi.org/10.3390/nano14050477 - 06 Mar 2024
Viewed by 619
Abstract
Photoelectric catalysis is a green and efficient way to degrade pollutants, which has been paid more and more attention by researchers. Among them, Bi2WO3 has been proved to have excellent photocatalytic oxidation activity on its {001} facets. In this study, [...] Read more.
Photoelectric catalysis is a green and efficient way to degrade pollutants, which has been paid more and more attention by researchers. Among them, Bi2WO3 has been proved to have excellent photocatalytic oxidation activity on its {001} facets. In this study, {001}-oriented facets with high exposure were successfully integrated into Bi2WO6 nanoplate arrays (Bi2WO6 NAs) to create a photoelectrode. This structure was grown in situ on an indium tin oxide (ITO) substrate. To promote photogenerated carrier separation efficiency and reduce agglomeration of Bi2WO6 photocatalysts, the electrochemical deposition of NiFe–layered double hydroxide (NiFe-LDH) and Ti3C2 (MXene) were introduced in this research to synergistically catalyze pollutant degradation. Morphology, spectral characterization, and electrochemical analysis jointly confirmed that the outstanding performance of hole capture behavior with LDH and electron conduction properties with MXene were the main reasons for the improvement in catalytic activity of the photoelectrode. Taking bisphenol A (BPA) as the model pollutant, the rate constant k of the NiFe-LDH/Ti3C2/Bi2WO6 NAs photoelectrode reaches 0.00196 min−1 under photoelectrocatalytic (PEC) conditions, which is 4.5 times that of the pure Bi2WO6 NAs photoelectrode. This work provides a new way to improve the reaction kinetics of the PEC degradation of pollutants. Full article
(This article belongs to the Special Issue Advanced Nanomaterials for Photocatalysis)
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18 pages, 8211 KiB  
Article
Nanometric Cu-ZnO Particles Supported on N-Doped Graphitic Carbon as Catalysts for the Selective CO2 Hydrogenation to Methanol
by Lu Peng, Bogdan Jurca, Alberto Garcia-Baldovi, Liang Tian, German Sastre, Ana Primo, Vasile Parvulescu, Amarajothi Dhakshinamoorthy and Hermenegildo Garcia
Nanomaterials 2024, 14(5), 476; https://doi.org/10.3390/nano14050476 - 06 Mar 2024
Viewed by 938
Abstract
The quest for efficient catalysts based on abundant elements that can promote the selective CO2 hydrogenation to green methanol still continues. Most of the reported catalysts are based on Cu/ZnO supported in inorganic oxides, with not much progress with respect to the [...] Read more.
The quest for efficient catalysts based on abundant elements that can promote the selective CO2 hydrogenation to green methanol still continues. Most of the reported catalysts are based on Cu/ZnO supported in inorganic oxides, with not much progress with respect to the benchmark Cu/ZnO/Al2O3 catalyst. The use of carbon supports for Cu/ZnO particles is much less explored in spite of the favorable strong metal support interaction that these doped carbons can establish. This manuscript reports the preparation of a series of Cu-ZnO@(N)C samples consisting of Cu/ZnO particles embedded within a N-doped graphitic carbon with a wide range of Cu/Zn atomic ratio. The preparation procedure relies on the transformation of chitosan, a biomass waste, into N-doped graphitic carbon by pyrolysis, which establishes a strong interaction with Cu nanoparticles (NPs) formed simultaneously by Cu2+ salt reduction during the graphitization. Zn2+ ions are subsequently added to the Cu–graphene material by impregnation. All the Cu/ZnO@(N)C samples promote methanol formation in the CO2 hydrogenation at temperatures from 200 to 300 °C, with the temperature increasing CO2 conversion and decreasing methanol selectivity. The best performing Cu-ZnO@(N)C sample achieves at 300 °C a CO2 conversion of 23% and a methanol selectivity of 21% that is among the highest reported, particularly for a carbon-based support. DFT calculations indicate the role of pyridinic N doping atoms stabilizing the Cu/ZnO NPs and supporting the formate pathway as the most likely reaction mechanism. Full article
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2 pages, 525 KiB  
Correction
Correction: Nguyen et al. Green Silver Nanoparticles Formed by Phyllanthus urinaria, Pouzolzia zeylanica, and Scoparia dulcis Leaf Extracts and the Antifungal Activity. Nanomaterials 2020, 10, 542
by Dai Hai Nguyen, Jung Seok Lee, Ki Dong Park, Yern Chee Ching, Xuan Thi Nguyen, V.H. Giang Phan and Thai Thanh Hoang Thi
Nanomaterials 2024, 14(5), 475; https://doi.org/10.3390/nano14050475 - 06 Mar 2024
Viewed by 504
Abstract
In the original publication [...] Full article
(This article belongs to the Special Issue Antibacterial Activity of Nanoparticles)
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12 pages, 3885 KiB  
Article
CoNiO2/Co3O4 Nanosheets on Boron Doped Diamond for Supercapacitor Electrodes
by Zheng Cui, Tianyi Wang, Ziyi Geng, Linfeng Wan, Yaofeng Liu, Siyu Xu, Nan Gao, Hongdong Li and Min Yang
Nanomaterials 2024, 14(5), 474; https://doi.org/10.3390/nano14050474 - 05 Mar 2024
Viewed by 716
Abstract
Developing novel supercapacitor electrodes with high energy density and good cycle stability has aroused great interest. Herein, the vertically aligned CoNiO2/Co3O4 nanosheet arrays anchored on boron doped diamond (BDD) films are designed and fabricated by a simple one-step [...] Read more.
Developing novel supercapacitor electrodes with high energy density and good cycle stability has aroused great interest. Herein, the vertically aligned CoNiO2/Co3O4 nanosheet arrays anchored on boron doped diamond (BDD) films are designed and fabricated by a simple one-step electrodeposition method. The CoNiO2/Co3O4/BDD electrode possesses a large specific capacitance (214 mF cm−2) and a long-term capacitance retention (85.9% after 10,000 cycles), which is attributed to the unique two-dimensional nanosheet architecture, high conductivity of CoNiO2/Co3O4 and the wide potential window of diamond. Nanosheet materials with an ultrathin thickness can decrease the diffusion length of ions, increase the contact area with electrolyte, as well as improve active material utilization, which leads to an enhanced electrochemical performance. Additionally, CoNiO2/Co3O4/BDD is fabricated as the positive electrode with activated carbon as the negative electrode, this assembled asymmetric supercapacitor exhibits an energy density of 7.5 W h kg−1 at a power density of 330.5 W kg−1 and capacity retention rate of 97.4% after 10,000 cycles in 6 M KOH. This work would provide insights into the design of advanced electrode materials for high-performance supercapacitors. Full article
(This article belongs to the Section Energy and Catalysis)
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36 pages, 24439 KiB  
Review
Progress in the Elimination of Organic Contaminants in Wastewater by Activation Persulfate over Iron-Based Metal–Organic Frameworks
by Keke Zhi, Jiajun Xu, Shi Li, Lingjie Luo, Dong Liu, Zhe Li, Lianghui Guo and Junwei Hou
Nanomaterials 2024, 14(5), 473; https://doi.org/10.3390/nano14050473 - 05 Mar 2024
Viewed by 864
Abstract
The release of organic contaminants has grown to be a major environmental concern and a threat to the ecology of water bodies. Persulfate-based Advanced Oxidation Technology (PAOT) is effective at eliminating hazardous pollutants and has an extensive spectrum of applications. Iron-based metal–organic frameworks [...] Read more.
The release of organic contaminants has grown to be a major environmental concern and a threat to the ecology of water bodies. Persulfate-based Advanced Oxidation Technology (PAOT) is effective at eliminating hazardous pollutants and has an extensive spectrum of applications. Iron-based metal–organic frameworks (Fe-MOFs) and their derivatives have exhibited great advantages in activating persulfate for wastewater treatment. In this article, we provide a comprehensive review of recent research progress on the significant potential of Fe-MOFs for removing antibiotics, organic dyes, phenols, and other contaminants from aqueous environments. Firstly, multiple approaches for preparing Fe-MOFs, including the MIL and ZIF series were introduced. Subsequently, removal performance of pollutants such as antibiotics of sulfonamides and tetracyclines (TC), organic dyes of rhodamine B (RhB) and acid orange 7 (AO7), phenols of phenol and bisphenol A (BPA) by various Fe-MOFs was compared. Finally, different degradation mechanisms, encompassing free radical degradation pathways and non-free radical degradation pathways were elucidated. This review explores the synthesis methods of Fe-MOFs and their application in removing organic pollutants from water bodies, providing insights for further refining the preparation of Fe-MOFs. Full article
(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)
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13 pages, 3033 KiB  
Article
Enhanced Aluminum-Ion Storage Properties of N-Doped Titanium Dioxide Electrode in Aqueous Aluminum-Ion Batteries
by Le Jian, Xibing Wu, Ruichun Li, Fangzheng Zhao, Peng Liu, Feng Wang, Daosheng Liu, Qingrong Yao and Jianqiu Deng
Nanomaterials 2024, 14(5), 472; https://doi.org/10.3390/nano14050472 - 05 Mar 2024
Viewed by 641
Abstract
Aqueous aluminum-ion batteries (AIBs) have great potential as devices for future large-scale energy storage systems due to the cost efficiency, environmentally friendly nature, and impressive theoretical energy density of Al. However, currently, available materials used as anodes for aqueous AIBs are scarce. In [...] Read more.
Aqueous aluminum-ion batteries (AIBs) have great potential as devices for future large-scale energy storage systems due to the cost efficiency, environmentally friendly nature, and impressive theoretical energy density of Al. However, currently, available materials used as anodes for aqueous AIBs are scarce. In this study, a novel sol-gel method was used to synthesize nitrogen-doped titanium dioxide (N-TiO2) as a potential anode material for AIBs in water. The annealed N-TiO2 showed a high discharge capacity of 43.2 mAh g−1 at a current density of 3 A g−1. Analysis of the electrode kinetics revealed that the N-TiO2 anodes exhibited rapid diffusion of aluminum ions, low resistance to charge transfer, and high electronic conductivity, enabling good rate performance. The successful implementation of a nitrogen-doping strategy provides a promising approach to enhance the electrochemical characteristics of electrode materials for aqueous AIBs. Full article
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32 pages, 4987 KiB  
Article
Glassy-like Transients in Semiconductor Nanomaterials
by Isaac Balberg
Nanomaterials 2024, 14(5), 471; https://doi.org/10.3390/nano14050471 - 05 Mar 2024
Viewed by 632
Abstract
Glassy behavior is manifested by three time-dependent characteristics of a dynamic physical property. Such behaviors have been found in the electrical conductivity transients of various disordered systems, but the mechanisms that yield the glassy behavior are still under intensive debate. The focus of [...] Read more.
Glassy behavior is manifested by three time-dependent characteristics of a dynamic physical property. Such behaviors have been found in the electrical conductivity transients of various disordered systems, but the mechanisms that yield the glassy behavior are still under intensive debate. The focus of the present work is on the effect of the quantum confinement (QC) and the Coulomb blockade (CB) effects on the experimentally observed glassy-like behavior in semiconductor nanomaterials. Correspondingly, we studied the transient electrical currents in semiconductor systems that contain CdSe or Si nanosize crystallites, as a function of that size and the ambient temperature. In particular, in contrast to the more commonly studied post-excitation behavior in electronic glassy systems, we have also examined the current transients during the excitation. This has enabled us to show that the glassy behavior is a result of the nanosize nature of the studied systems and thus to conclude that the observed characteristics are sensitive to the above effects. Following this and the temperature dependence of the transients, we derived a more detailed macroscopic and microscopic understanding of the corresponding transport mechanisms and their glassy manifestations. We concluded that the observed electrical transients must be explained not only by the commonly suggested principle of the minimization of energy upon the approach to equilibrium, as in the mechanical (say, viscose) glass, but also by the principle of minimal energy dissipation by the electrical current which determines the percolation network of the electrical conductivity. We further suggest that the deep reason for the glassy-like behavior that is observed in the electrical transients of the nanomaterials studied is the close similarity between the localization range of electrons due to the Coulomb blockade and the caging range of the uncharged atomic-size particles in the classical mechanical glass. These considerations are expected to be useful for the understanding and planning of semiconductor nanodevices such as corresponding quantum dot memories and quantum well MOSFETs. Full article
(This article belongs to the Special Issue Semiconductor Nanomaterials for Optoelectronic Applications)
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15 pages, 10847 KiB  
Article
Photocatalytic Degradation of Organic Pollutants—Nile Blue, Methylene Blue, and Bentazon Herbicide—Using NiO-ZnO Nanocomposite
by Sadaf Yasmeen, Luca Burratti, Leonardo Duranti, Emanuela Sgreccia and Paolo Prosposito
Nanomaterials 2024, 14(5), 470; https://doi.org/10.3390/nano14050470 - 05 Mar 2024
Viewed by 900
Abstract
Water pollution poses a significant threat to both human health and ecosystem integrity. Chemical pollutants such as dyes and pesticides affect the water quality and endanger aquatic life. Among the methods for water purification from organic pollutants, photodegradation is certainly a valid technique [...] Read more.
Water pollution poses a significant threat to both human health and ecosystem integrity. Chemical pollutants such as dyes and pesticides affect the water quality and endanger aquatic life. Among the methods for water purification from organic pollutants, photodegradation is certainly a valid technique to decrease such contaminants. In this work, pristine NiO, ZnO, and NiO-ZnO photocatalysts were synthesized by the homogeneous co-precipitation method. X-ray diffraction confirms the formation of a photocatalyst consisting of ZnO (Hexagonal) and NiO (Cubic) structures. The crystalline size was calculated by the Scherrer formula, which is 19 nm for the NiO-ZnO photocatalyst. The band gap measurements of the prepared samples were obtained using the Tauc Plot, equation which is 2.93 eV, 3.35 eV and 2.63 eV for NiO, ZnO, and NiO-ZnO photocatalysts, respectively. The photocatalytic performance of NiO-ZnO nanocomposite was evaluated through the degradation of Methylene Blue and Nile Blue dyes under sunlight, and Bentazon herbicide under a UV light. Photocatalyst degradation efficiency was 95% and 97% for Methylene Blue and Nile Blue in 220 min under sunlight while a degradation of 70% for Bentazon after 100 min under UV light source was found. Full article
(This article belongs to the Special Issue Nanomaterials in Water Applications)
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24 pages, 2443 KiB  
Review
An Updated Overview of Silica Aerogel-Based Nanomaterials
by Adelina-Gabriela Niculescu, Dana-Ionela Tudorache, Maria Bocioagă, Dan Eduard Mihaiescu, Tony Hadibarata and Alexandru Mihai Grumezescu
Nanomaterials 2024, 14(5), 469; https://doi.org/10.3390/nano14050469 - 04 Mar 2024
Cited by 1 | Viewed by 1237
Abstract
Silica aerogels have gained much interest due to their unique properties, such as being the lightest solid material, having small pore sizes, high porosity, and ultralow thermal conductivity. Also, the advancements in synthesis methods have enabled the creation of silica aerogel-based composites in [...] Read more.
Silica aerogels have gained much interest due to their unique properties, such as being the lightest solid material, having small pore sizes, high porosity, and ultralow thermal conductivity. Also, the advancements in synthesis methods have enabled the creation of silica aerogel-based composites in combination with different materials, for example, polymers, metals, and carbon-based structures. These new silica-based materials combine the properties of silica with the other materials to create a new and reinforced architecture with significantly valuable uses in different fields. Therefore, the importance of silica aerogels has been emphasized by presenting their properties, synthesis process, composites, and numerous applications, offering an updated background for further research in this interdisciplinary domain. Full article
(This article belongs to the Collection Metallic and Metal Oxide Nanohybrids and Their Applications)
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17 pages, 4706 KiB  
Article
Improvement of Electrical Conductivity of In Situ Iodine-Doped Polypyrrole Film Using Atmospheric Pressure Plasma Reactor with Capillary Electrodes
by Eun Young Jung, Salman Khalil, Hyojun Jang, Habeeb Olaitan Suleiman, Jae Young Kim, Bhum Jae Shin, Heung-Sik Tae and Choon-Sang Park
Nanomaterials 2024, 14(5), 468; https://doi.org/10.3390/nano14050468 - 04 Mar 2024
Viewed by 731
Abstract
To improve the electrical conductivity of polypyrrole (PPy) nanostructure film through in situ iodine (I2) doping, this study proposes an atmospheric pressure plasma reactor (APPR) where heated I2 dopant vapor is fed through capillary electrodes that serve as electrodes for [...] Read more.
To improve the electrical conductivity of polypyrrole (PPy) nanostructure film through in situ iodine (I2) doping, this study proposes an atmospheric pressure plasma reactor (APPR) where heated I2 dopant vapor is fed through capillary electrodes that serve as electrodes for discharge ignition. A large amount of the heated I2 vapor introduced into the reactor separately from a monomer gas can be effectively activated by an intense plasma via capillary electrodes. In particular, intensive plasma is obtained by properly adjusting the bluff body position in the APPR. Based on the ICCD and OES results, the I2 vapor injected through the capillary nozzle electrode is observed to form I2 charge species. The formed I2 species could directly participate in growing in situ I2-doped PPy films. Thus, in situ I2-doped PPy nanostructure films grown using the proposed APPR exhibit higher thicknesses of 15.3 μm and good electrical conductivities, compared to the corresponding non-doped films. Full article
(This article belongs to the Special Issue Synthesis of Nanostructures in Gas-Discharge Plasma)
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16 pages, 3253 KiB  
Article
Polymer-Clay Nanocomposites for the Uptake of Hazardous Anions
by Huaibin Zhang, Wenyan Huang and Sridhar Komarneni
Nanomaterials 2024, 14(5), 467; https://doi.org/10.3390/nano14050467 - 04 Mar 2024
Viewed by 594
Abstract
Polymer intercalated clay nanocomposites were prepared from various montmorillonites (Mt) and a polymer, polydiallyldimethylammonim (PDDA) chloride. X-ray diffraction (XRD) analysis of the above polymer intercalated nanocomposites showed either no crystalline peaks or very broad peaks with the intercalation of PDDA polymer in the [...] Read more.
Polymer intercalated clay nanocomposites were prepared from various montmorillonites (Mt) and a polymer, polydiallyldimethylammonim (PDDA) chloride. X-ray diffraction (XRD) analysis of the above polymer intercalated nanocomposites showed either no crystalline peaks or very broad peaks with the intercalation of PDDA polymer in the interlayers, probably as a result of exfoliation of the clay layers. Infrared spectroscopy revealed the presence of PDDA in all the clay nanocomposite materials. The maximum adsorption capacities of nitrate, perchlorate, and chromate by one of the polymer intercalated nanocomposite materials prepared from montmorillonite, Kunipea were 0.40 mmol·g1, 0.44 mmol·g1 and 0.299 mmol·g1, respectively. The other two polymer intercalated nanocomposites prepared with montmorillonites from Wyoming and China showed very good adsorption capacities for perchlorate but somewhat lower uptake capacities for chromate and nitrate compared to the nanocomposite prepared from montmorillonite from Kunipea. The uptake of nitrate, perchlorate and chromate by the polymer intercalated nanocomposites could be well described using the Freundlich isotherm while their uptake kinetics fitted well to the pseudo-second-order model. The uptake kinetics of nitrate, perchlorate, and chromate were found to be fast as equilibrium was reached within 4 h. Moreover, the uptakes of chromate by polymer intercalated nanocomposites were found to be highly selective in the presence of Cl, SO42 and CO32, the most abundant naturally occurring anions. Full article
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12 pages, 3623 KiB  
Article
Dependence of Positive Bias Stress Instability on Threshold Voltage and Its Origin in Solution-Processed Aluminum-Doped Indium Oxide Thin-Film Transistors
by Jeong-Hyeon Na, Jun-Hyeong Park, Won Park, Junhao Feng, Jun-Su Eun, Jinuk Lee, Sin-Hyung Lee, Jaewon Jang, In Man Kang, Do-Kyung Kim and Jin-Hyuk Bae
Nanomaterials 2024, 14(5), 466; https://doi.org/10.3390/nano14050466 - 04 Mar 2024
Viewed by 728
Abstract
The initial electrical characteristics and bias stabilities of thin-film transistors (TFTs) are vital factors regarding the practical use of electronic devices. In this study, the dependence of positive bias stress (PBS) instability on an initial threshold voltage (VTH) and its origin [...] Read more.
The initial electrical characteristics and bias stabilities of thin-film transistors (TFTs) are vital factors regarding the practical use of electronic devices. In this study, the dependence of positive bias stress (PBS) instability on an initial threshold voltage (VTH) and its origin were analyzed by understanding the roles of slow and fast traps in solution-processed oxide TFTs. To control the initial VTH of oxide TFTs, the indium oxide (InOx) semiconductor was doped with aluminum (Al), which functioned as a carrier suppressor. The concentration of oxygen vacancies decreased as the Al doping concentration increased, causing a positive VTH shift in the InOx TFTs. The VTH shift (∆VTH) caused by PBS increased exponentially when VTH was increased, and a distinct tendency was observed as the gate bias stress increased due to a high vertical electric field in the oxide dielectric. In addition, the recovery behavior was analyzed to reveal the influence of fast and slow traps on ∆VTH by PBS. Results revealed that the effect of the slow trap increased as the VTH moved in the positive direction; this occured because the main electron trap location moved away from the interface as the Fermi level approached the conduction band minimum. Understanding the correlation between VTH and PBS instability can contribute to optimizing the fabrication of oxide TFT-based circuits for electronic applications. Full article
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30 pages, 4620 KiB  
Review
Recent Advances in Tactile Sensory Systems: Mechanisms, Fabrication, and Applications
by Jianguo Xi, Huaiwen Yang, Xinyu Li, Ruilai Wei, Taiping Zhang, Lin Dong, Zhenjun Yang, Zuqing Yuan, Junlu Sun and Qilin Hua
Nanomaterials 2024, 14(5), 465; https://doi.org/10.3390/nano14050465 - 04 Mar 2024
Viewed by 1505
Abstract
Flexible electronics is a cutting-edge field that has paved the way for artificial tactile systems that mimic biological functions of sensing mechanical stimuli. These systems have an immense potential to enhance human–machine interactions (HMIs). However, tactile sensing still faces formidable challenges in delivering [...] Read more.
Flexible electronics is a cutting-edge field that has paved the way for artificial tactile systems that mimic biological functions of sensing mechanical stimuli. These systems have an immense potential to enhance human–machine interactions (HMIs). However, tactile sensing still faces formidable challenges in delivering precise and nuanced feedback, such as achieving a high sensitivity to emulate human touch, coping with environmental variability, and devising algorithms that can effectively interpret tactile data for meaningful interactions in diverse contexts. In this review, we summarize the recent advances of tactile sensory systems, such as piezoresistive, capacitive, piezoelectric, and triboelectric tactile sensors. We also review the state-of-the-art fabrication techniques for artificial tactile sensors. Next, we focus on the potential applications of HMIs, such as intelligent robotics, wearable devices, prosthetics, and medical healthcare. Finally, we conclude with the challenges and future development trends of tactile sensors. Full article
(This article belongs to the Special Issue Advances in Flexible Nanoelectronics)
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21 pages, 4058 KiB  
Review
Developments in Atomistic and Nano Structure Evolution Mechanisms of Molten Slag Using Atomistic Simulation Methods
by Chunhe Jiang, Kejiang Li, Zhisheng Bi, Shufang Ma, Jianliang Zhang, Bo Liu and Jiaqi Li
Nanomaterials 2024, 14(5), 464; https://doi.org/10.3390/nano14050464 - 03 Mar 2024
Viewed by 797
Abstract
Molten slag has different properties depending on its composition. The relationship between its composition, structure, and properties has been the focus of attention in industrial manufacturing processes. This review describes the atomistic scale mechanisms by which oxides of different compositions affect the properties [...] Read more.
Molten slag has different properties depending on its composition. The relationship between its composition, structure, and properties has been the focus of attention in industrial manufacturing processes. This review describes the atomistic scale mechanisms by which oxides of different compositions affect the properties and structure of slag, and depicts the current state of research in the atomic simulation of molten slag. At present, the research on the macroscopic properties of molten slag mainly focuses on viscosity, free-running temperature, melting point, and desulphurization capacity. Regulating the composition has become the most direct and effective way to control slag properties. Analysis of the microevolution mechanism is the fundamental way to grasp the macroscopic properties. The microstructural evolution mechanism, especially at the atomic and nanoscale of molten slag, is reviewed from three aspects: basic oxides, acidic oxides, and amphoteric oxides. The evolution of macroscopic properties is analyzed in depth through the evolution of the atomic structure. Resolution of the macroscopic properties of molten slag by the atomic structure plays a crucial role in the development of fundamental theories of physicochemistry. Full article
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11 pages, 2842 KiB  
Article
Fish Scale for Wearable, Self-Powered TENG
by Liwei Zhao, Jin Han, Xing Zhang and Chunchang Wang
Nanomaterials 2024, 14(5), 463; https://doi.org/10.3390/nano14050463 - 03 Mar 2024
Viewed by 2732
Abstract
Flexible and wearable devices are attracting more and more attention. Herein, we propose a self-powered triboelectric nanogenerator based on the triboelectric effect of fish scales. As the pressure on the nanogenerator increases, the output voltage of the triboelectric nanogenerator increases. The nanogenerator can [...] Read more.
Flexible and wearable devices are attracting more and more attention. Herein, we propose a self-powered triboelectric nanogenerator based on the triboelectric effect of fish scales. As the pressure on the nanogenerator increases, the output voltage of the triboelectric nanogenerator increases. The nanogenerator can output a voltage of 7.4 V and a short-circuit current of 0.18 μA under a pressure of 50 N. The triboelectric effect of fish scales was argued to be related to the lamellar structure composed of collagen fiber bundles. The nanogenerator prepared by fish scales can sensitively perceive human activities such as walking, finger tapping, and elbow bending. Moreover, fish scales are a biomass material with good biocompatibility with the body. The fish-scale nanogenerator is a kind of flexible, wearable, and self-powered triboelectric nanogenerator showing great prospects in healthcare and body information monitoring. Full article
(This article belongs to the Special Issue Nanoelectronics: Materials, Devices and Applications)
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19 pages, 8739 KiB  
Article
Tailoring Mesoporous Silica-Coated Silver Nanoparticles and Polyurethane-Doped Films for Enhanced Antimicrobial Applications
by Silvia Nuti, Adrián Fernández-Lodeiro, Joana Galhano, Elisabete Oliveira, Maria Paula Duarte, José Luis Capelo-Martínez, Carlos Lodeiro and Javier Fernández-Lodeiro
Nanomaterials 2024, 14(5), 462; https://doi.org/10.3390/nano14050462 - 02 Mar 2024
Viewed by 913
Abstract
The global increase in multidrug-resistant bacteria poses a challenge to public health and requires the development of new antibacterial materials. In this study, we examined the bactericidal properties of mesoporous silica-coated silver nanoparticles, varying the core sizes (ca. 28 nm and 51 nm). [...] Read more.
The global increase in multidrug-resistant bacteria poses a challenge to public health and requires the development of new antibacterial materials. In this study, we examined the bactericidal properties of mesoporous silica-coated silver nanoparticles, varying the core sizes (ca. 28 nm and 51 nm). We also investigated gold nanoparticles (ca. 26 nm) coated with mesoporous silica as possible inert metal cores. To investigate the modification of antimicrobial activity after the surface charge change, we used silver nanoparticles with a silver core of 28 nm coated with a mesoporous shell (ca. 16 nm) and functionalized with a terminal amine group. Furthermore, we developed a facile method to create mesoporous silica-coated silver nanoparticles (Ag@mSiO2) doped films using polyurethane (IROGRAN®) as a polymer matrix via solution casting. The antibacterial effects of silver nanoparticles with different core sizes were analyzed against Gram-negative and Gram-positive bacteria relevant to the healthcare and food industry. The results demonstrated that gold nanoparticles were inert, while silver nanoparticles exhibited antibacterial effects against Gram-negative (Escherichia coli and Salmonella enterica subsp. enterica serovar Choleraesuis) and Gram-positive (Bacillus cereus) strains. In particular, the larger Ag@mSiO2 nanoparticles showed a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of 18 µg/mL in the Salmonella strain. Furthermore, upon terminal amine functionalization, reversing the surface charge to positive values, there was a significant increase in the antibacterial activity of the NPs compared to their negative counterparts. Finally, the antimicrobial properties of the nanoparticle-doped polyurethane films revealed a substantial improvement in antibacterial efficacy. This study provides valuable information on the potential of mesoporous silica-coated silver nanoparticles and their applications in fighting multidrug-resistant bacteria, especially in the healthcare and food industries. Full article
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27 pages, 5123 KiB  
Article
Thermodynamic and Kinetic Simulations Used for the Study of the Influence of Precipitates on Thermophysical Properties in NiTiCu Alloys Obtained by Spark Plasma Sintering
by Cristiana Diana Cirstea, Erwin Povoden-Karadeniz, Vasile Cirstea, Felicia Tolea and Ernst Kozeschnik
Nanomaterials 2024, 14(5), 461; https://doi.org/10.3390/nano14050461 - 02 Mar 2024
Viewed by 649
Abstract
The thermodynamic and kinetic simulations based on the re-assessment of the thermodynamic and kinetic database of the Ni-Ti-Cu system were employed to predict the phenomena of mechanical alloying, spark plasma sintering and thermal properties of the intriguing Ni-Ti-Cu system. Thermodynamic calculations are presented [...] Read more.
The thermodynamic and kinetic simulations based on the re-assessment of the thermodynamic and kinetic database of the Ni-Ti-Cu system were employed to predict the phenomena of mechanical alloying, spark plasma sintering and thermal properties of the intriguing Ni-Ti-Cu system. Thermodynamic calculations are presented for the stable and unstable phases of NiTiCu materials and support a correlation with the evolving microstructure during the technological process. Also, the thermal conductivity, the thermal diffusivity and the specific heat of spark plasma sintered and aged Cu-alloyed NiTi-based shape memory alloys (NiTiCu) with two compositions, Ni45Ti50Cu5 and Ni40Ti50Cu10, are evaluated and the influence of mechanical alloying and precipitates on thermal properties is discussed. Measurements of these thermal properties were carried out from 25 °C up to 175 °C using the laser flash method, as well as differential scanning calorimetry. The thermal hysteresis of the 20 mm diameter samples was between 8.8 and 24.5 °C. The observed T0 temperatures from DSC experimental transformation features are in reasonable accordance with the thermodynamic predictions. The determined k values are between 20.04 and 26.87 W/m K and in agreement with the literature results. Moreover, this paper can provide some suggestions for the preparation of NiTiCu shape memory alloys and their applications. Full article
(This article belongs to the Special Issue Nanostructural Processing Effects in Shape Memory Alloys)
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36 pages, 5342 KiB  
Review
Diamond for High-Power, High-Frequency, and Terahertz Plasma Wave Electronics
by Muhammad Mahmudul Hasan, Chunlei Wang, Nezih Pala and Michael Shur
Nanomaterials 2024, 14(5), 460; https://doi.org/10.3390/nano14050460 - 01 Mar 2024
Viewed by 880
Abstract
High thermal conductivity and a high breakdown field make diamond a promising candidate for high-power and high-temperature semiconductor devices. Diamond also has a higher radiation hardness than silicon. Recent studies show that diamond has exceptionally large electron and hole momentum relaxation times, facilitating [...] Read more.
High thermal conductivity and a high breakdown field make diamond a promising candidate for high-power and high-temperature semiconductor devices. Diamond also has a higher radiation hardness than silicon. Recent studies show that diamond has exceptionally large electron and hole momentum relaxation times, facilitating compact THz and sub-THz plasmonic sources and detectors working at room temperature and elevated temperatures. The plasmonic resonance quality factor in diamond TeraFETs could be larger than unity for the 240–600 GHz atmospheric window, which could make them viable for 6G communications applications. This paper reviews the potential and challenges of diamond technology, showing that diamond might augment silicon for high-power and high-frequency compact devices with special advantages for extreme environments and high-frequency applications. Full article
(This article belongs to the Special Issue Advances in Nanotechnology for RF and Terahertz)
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2 pages, 156 KiB  
Correction
Correction: Ji et al. Mesoporous Cobalt Oxide (CoOx) Nanowires with Different Aspect Ratios for High Performance Hybrid Supercapacitors. Nanomaterials 2023, 13, 749
by Haomin Ji, Yifei Ma, Zhuo Cai, Micun Yun, Jiemin Han, Zhaomin Tong, Mei Wang, Jonghwan Suhr, Liantuan Xiao, Suotang Jia and Xuyuan Chen
Nanomaterials 2024, 14(5), 459; https://doi.org/10.3390/nano14050459 - 01 Mar 2024
Viewed by 522
Abstract
There was an error in the original publication [...] Full article
(This article belongs to the Special Issue Nanomaterials for Supercapacitors)
26 pages, 7420 KiB  
Article
Predicting Ion Sequestration in Charged Polymers with the Steepest-Entropy-Ascent Quantum Thermodynamic Framework
by Jared McDonald, Michael R. von Spakovsky and William T. Reynolds
Nanomaterials 2024, 14(5), 458; https://doi.org/10.3390/nano14050458 - 01 Mar 2024
Viewed by 664
Abstract
The steepest-entropy-ascent quantum thermodynamic framework is used to investigate the effectiveness of multi-chain polyethyleneimine-methylenephosphonic acid in sequestering rare-earth ions (Eu3+) from aqueous solutions. The framework applies a thermodynamic equation of motion to a discrete energy eigenstructure to model the binding kinetics [...] Read more.
The steepest-entropy-ascent quantum thermodynamic framework is used to investigate the effectiveness of multi-chain polyethyleneimine-methylenephosphonic acid in sequestering rare-earth ions (Eu3+) from aqueous solutions. The framework applies a thermodynamic equation of motion to a discrete energy eigenstructure to model the binding kinetics of europium ions to reactive sites of the polymer chains. The energy eigenstructure is generated using a non-Markovian Monte Carlo model that estimates energy level degeneracies. The equation of motion is used to determine the occupation probability of each energy level, describing the unique path through thermodynamic state space by which the polymer system sequesters rare-earth ions from solution. A second Monte Carlo simulation is conducted to relate the kinetic path in state space to physical descriptors associated with the polymer, including the radius of gyration, tortuosity, and Eu-neighbor distribution functions. These descriptors are used to visualize the evolution of the polymer during the sequestration process. The fraction of sequestered Eu3+ ions depends upon the total energy of the system, with lower energy resulting in greater sequestration. The kinetics of the overall sequestration are dependent on the steepest-entropy-ascent principle used by the equation of motion to generate a unique kinetic path from an initial non-equilibrium state. Full article
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21 pages, 11621 KiB  
Article
In Vivo Assessment of Hepatic and Kidney Toxicity Induced by Silicon Quantum Dots in Mice
by Roxana-Elena Cristian, Cornel Balta, Hildegard Herman, Bogdan Trica, Beatrice G. Sbarcea, Anca Hermenean, Anca Dinischiotu and Miruna S. Stan
Nanomaterials 2024, 14(5), 457; https://doi.org/10.3390/nano14050457 - 01 Mar 2024
Viewed by 776
Abstract
In the last decade, silicon-based quantum dots (SiQDs) have attracted the attention of researchers due to their unique properties for which they are used in medical applications and in vivo imaging. Detection of cytotoxic effects in vivo is essential for understanding the mechanisms [...] Read more.
In the last decade, silicon-based quantum dots (SiQDs) have attracted the attention of researchers due to their unique properties for which they are used in medical applications and in vivo imaging. Detection of cytotoxic effects in vivo is essential for understanding the mechanisms of toxicity, a mandatory step before their administration to human subjects. In this context, we aimed to evaluate the in vivo hepatic and renal acute toxicity of SiQDs obtained by laser ablation. The nanoparticles were administrated at different doses (0, 1, 10, and 100 mg of QDs/kg of body weight) by intravenous injection into the caudal vein of Swiss mice. After 1, 6, 24, and 72 h, the animals were euthanatized, and liver and kidney tissues were used in further toxicity tests. The time- and dose-dependent effects of SiQDs on the antioxidant defense system of mice liver and kidney were investigated by quantifying the activity of antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase) in correlation with the morphological changes and inflammatory status in the liver and kidneys. The results showed a decrease in the activities of antioxidant enzymes and histopathological changes, except for superoxide dismutase, in which no significant changes were registered compared with the control. Furthermore, the immunohistochemical expression of TNF-α was significant at doses over 10 mg of QDs/kg of body weight and were still evident at 72 h after administration. Our results showed that doses under 10 mg of SiQDs/kg of b.w. did not induce hepatic and renal toxicity, providing useful information for further clinical trials. Full article
(This article belongs to the Special Issue Advances in Nanotoxicology: Health and Safety)
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6 pages, 196 KiB  
Editorial
Recent Development of Nanomaterials for Chemical Engineering
by Meiwen Cao
Nanomaterials 2024, 14(5), 456; https://doi.org/10.3390/nano14050456 - 01 Mar 2024
Viewed by 678
Abstract
There has been an explosive growth in research on nanomaterials since the late 1980s and early 1990s [...] Full article
(This article belongs to the Special Issue Nanomaterials for Chemical Engineering (Volume II))
20 pages, 6397 KiB  
Article
Dimensions of Cellulose Nanocrystals from Cotton and Bacterial Cellulose: Comparison of Microscopy and Scattering Techniques
by Vladimir Grachev, Olivier Deschaume, Peter R. Lang, Minne Paul Lettinga, Carmen Bartic and Wim Thielemans
Nanomaterials 2024, 14(5), 455; https://doi.org/10.3390/nano14050455 - 29 Feb 2024
Viewed by 860
Abstract
Different microscopy and scattering methods used in the literature to determine the dimensions of cellulose nanocrystals derived from cotton and bacterial cellulose were compared to investigate potential bias and discrepancies. Atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), depolarized dynamic light scattering (DDLS), [...] Read more.
Different microscopy and scattering methods used in the literature to determine the dimensions of cellulose nanocrystals derived from cotton and bacterial cellulose were compared to investigate potential bias and discrepancies. Atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), depolarized dynamic light scattering (DDLS), and static light scattering (SLS) were compared. The lengths, widths, and heights of the particles and their respective distributions were determined by AFM. In agreement with previous work, the CNCs were found to have a ribbon-like shape, regardless of the source of cellulose or the surface functional groups. Tip broadening and agglomeration of the particles during deposition cause AFM-derived lateral dimensions to be systematically larger those obtained from SAXS measurements. The radius of gyration determined by SLS showed a good correlation with the dimensions obtained by AFM. The hydrodynamic lateral dimensions determined by DDLS were found to have the same magnitude as either the width or height obtained from the other techniques; however, the precision of DDLS was limited due to the mismatch between the cylindrical model and the actual shape of the CNCs, and to constraints in the fitting procedure. Therefore, the combination of AFM and SAXS, or microscopy and small-angle scattering, is recommended for the most accurate determination of CNC dimensions. Full article
(This article belongs to the Section Synthesis, Interfaces and Nanostructures)
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18 pages, 6170 KiB  
Article
Two-Dimensional MXene as a Promising Adsorbent for Trihalomethanes Removal: A Density-Functional Theory Study
by Islam Gomaa, Nasser Mohammed Hosny, Hanan Elhaes, Hend A. Ezzat, Maryam G. Elmahgary and Medhat A. Ibrahim
Nanomaterials 2024, 14(5), 454; https://doi.org/10.3390/nano14050454 - 29 Feb 2024
Viewed by 797
Abstract
This groundbreaking research delves into the intricate molecular interactions between MXene and trihalomethanes (THs) through a comprehensive theoretical study employing density-functional theory (DFT). Trihalomethanes are common carcinogenic chlorination byproducts found in water sanitation systems. This study focuses on a pristine MXene [Mn+1 [...] Read more.
This groundbreaking research delves into the intricate molecular interactions between MXene and trihalomethanes (THs) through a comprehensive theoretical study employing density-functional theory (DFT). Trihalomethanes are common carcinogenic chlorination byproducts found in water sanitation systems. This study focuses on a pristine MXene [Mn+1·Xn] monolayer and its various terminal [Tx] functional groups [Mn+1·XnTx], strategically placed on the surface for enhanced performance. Our investigation involves a detailed analysis of the adsorption energies of THs on different MXene types, with the MXene-Cl layer emerging as the most compatible variant. This specific MXene-Cl layer exhibits remarkable properties, including a total dipole moment (TDM) of 12.443 Debye and a bandgap of 0.570 eV, achieved through meticulous geometry optimization and computational techniques. Notably, THs such as trichloromethane (CHCl3), bromide-chloromethane (CHBrCl2), and dibromochloromethane (CHBr2Cl) demonstrate the highest TDM values, indicating substantial changes in electronic and optical parameters, with TDM values of 16.363, 15.998, and 16.017 Debye, respectively. These findings highlight the potential of the MXene-Cl layer as an effective adsorbent and detector for CHF3, CHClF2, CHCl3, CHBrCl2, and CHBr2Cl. Additionally, we observe a proportional increase in the TDM and bandgap energy, indicative of conductivity, for various termination atom combinations, such as Mxene-O-OH, Mxene-O-F, Mxene-O-Cl, Mxene-OH-F, Mxene-F-Cl, and Mxene-OH-Cl, with bandgap energies measured at 0.734, 0.940, 1.120, 0.835, and 0.927 eV, respectively. Utilizing DFT, we elucidate the adsorption energies of THs on different MXene surfaces. Our results conclusively demonstrate the significant influence of the termination atom nature and quantity on MXene’s primitive TDM value. This research contributes to our understanding of MXene–THs interactions, offering promising avenues for the development of efficient adsorbents and detectors for THs. Ultimately, these advancements hold the potential to revolutionize water sanitation practices and enhance environmental safety. Full article
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11 pages, 2189 KiB  
Article
Sub-Nanomolar Detection of Oligonucleotides Using Molecular Beacons Immobilized on Lightguiding Nanowires
by Therese B. Johansson, Rubina Davtyan, Julia Valderas-Gutiérrez, Adrian Gonzalez Rodriguez, Björn Agnarsson, Roberto Munita, Thoas Fioretos, Henrik Lilljebjörn, Heiner Linke, Fredrik Höök and Christelle N. Prinz
Nanomaterials 2024, 14(5), 453; https://doi.org/10.3390/nano14050453 - 29 Feb 2024
Viewed by 633
Abstract
The detection of oligonucleotides is a central step in many biomedical investigations. The most commonly used methods for detecting oligonucleotides often require concentration and amplification before detection. Therefore, developing detection methods with a direct read-out would be beneficial. Although commonly used for the [...] Read more.
The detection of oligonucleotides is a central step in many biomedical investigations. The most commonly used methods for detecting oligonucleotides often require concentration and amplification before detection. Therefore, developing detection methods with a direct read-out would be beneficial. Although commonly used for the detection of amplified oligonucleotides, fluorescent molecular beacons have been proposed for such direct detection. However, the reported limits of detection using molecular beacons are relatively high, ranging from 100 nM to a few µM, primarily limited by the beacon fluorescence background. In this study, we enhanced the relative signal contrast between hybridized and non-hybridized states of the beacons by immobilizing them on lightguiding nanowires. Upon hybridization to a complementary oligonucleotide, the fluorescence from the surface-bound beacon becomes coupled in the lightguiding nanowire core and is re-emitted at the nanowire tip in a narrower cone of light compared with the standard 4π emission. Prior knowledge of the nanowire positions allows for the continuous monitoring of fluorescence signals from each nanowire, which effectively facilitates the discrimination of signals arising from hybridization events against background signals. This resulted in improved signal-to-background and signal-to-noise ratios, which allowed for the direct detection of oligonucleotides at a concentration as low as 0.1 nM. Full article
(This article belongs to the Section Biology and Medicines)
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17 pages, 5536 KiB  
Article
A Photochemically Active Cu2O Nanoparticle Endows Scaffolds with Good Antibacterial Performance by Efficiently Generating Reactive Oxygen Species
by Yushan He, Jun Zan, Zihui He, Xinna Bai, Cijun Shuai and Hao Pan
Nanomaterials 2024, 14(5), 452; https://doi.org/10.3390/nano14050452 - 29 Feb 2024
Viewed by 665
Abstract
Cuprous oxide (Cu2O) has great potential in photodynamic therapy for implant-associated infections due to its good biocompatibility and photoelectric properties. Nevertheless, the rapid recombination of electrons and holes weakens its photodynamic antibacterial effect. In this work, a new nanosystem (Cu2 [...] Read more.
Cuprous oxide (Cu2O) has great potential in photodynamic therapy for implant-associated infections due to its good biocompatibility and photoelectric properties. Nevertheless, the rapid recombination of electrons and holes weakens its photodynamic antibacterial effect. In this work, a new nanosystem (Cu2O@rGO) with excellent photodynamic performance was designed via the in situ growth of Cu2O on reduced graphene oxide (rGO). Specifically, rGO with lower Fermi levels served as an electron trap to capture photoexcited electrons from Cu2O, thereby promoting electron-hole separation. More importantly, the surface of rGO could quickly transfer electrons from Cu2O owing to its excellent conductivity, thus efficiently suppressing the recombination of electron-hole pairs. Subsequently, the Cu2O@rGO nanoparticle was introduced into poly-L-lactic acid (PLLA) powder to prepare PLLA/Cu2O@rGO porous scaffolds through selective laser sintering. Photochemical analysis showed that the photocurrent of Cu2O@rGO increased by about two times after the incorporation of GO nanosheets, thus enhancing the efficiency of photogenerated charge carriers and promoting electron-hole separation. Moreover, the ROS production of the PLLA/Cu2O@rGO scaffold was significantly increased by about two times as compared with that of the PLLA/Cu2O scaffold. The antibacterial results showed that PLLA/Cu2O@rGO possessed antibacterial rates of 83.7% and 81.3% against Escherichia coli and Staphylococcus aureus, respectively. In summary, this work provides an effective strategy for combating implant-related infections. Full article
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