Nanomaterials

9 pages, 1458 KiB

Open AccessArticle

Structural, Electronic and Magnetic Properties of a Few Nanometer-Thick Superconducting NdBa₂Cu₃O₇ Films

by Marco Moretti Sala, Marco Salluzzo, Matteo Minola, Gabriella Maria De Luca, Greta Dellea, Vesna Srot, Yi Wang, Peter A. van Aken, Matthieu Le Tacon, Bernhard Keimer, Claudia Dallera, Lucio Braicovich and Giacomo Ghiringhelli

Nanomaterials 2020, 10(4), 817; https://doi.org/10.3390/nano10040817 - 24 Apr 2020

Cited by 1 | Viewed by 4144

Abstract

Epitaxial films of high critical temperature (

T_{c}

) cuprate superconductors preserve their transport properties even when their thickness is reduced to a few nanometers. However, when approaching the single crystalline unit cell (u.c.) of thickness,

T_{c}

decreases and eventually, superconductivity [...] Read more.

Epitaxial films of high critical temperature (

T_{c}

) cuprate superconductors preserve their transport properties even when their thickness is reduced to a few nanometers. However, when approaching the single crystalline unit cell (u.c.) of thickness,

T_{c}

decreases and eventually, superconductivity is lost. Strain originating from the mismatch with the substrate, electronic reconstruction at the interface and alteration of the chemical composition and of doping can be the cause of such changes. Here, we use resonant inelastic x-ray scattering at the Cu

L_{3}

edge to study the crystal field and spin excitations of NdBa

_{2}

Cu

_{3}

O

_{7 - x}

ultrathin films grown on SrTiO

_{3}

, comparing 1, 2 and 80 u.c.-thick samples. We find that even at extremely low thicknesses, the strength of the in-plane superexchange interaction is mostly preserved, with just a slight decrease in the 1 u.c. with respect to the 80 u.c.-thick sample. We also observe spectroscopic signatures for a decrease of the hole-doping at low thickness, consistent with the expansion of the c-axis lattice parameter and oxygen deficiency in the chains of the first unit cell, determined by high-resolution transmission microscopy and x-ray diffraction. Full article

(This article belongs to the Special Issue Synchrotron Radiation Techniques for the Investigation of Nanomaterials)

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12 pages, 2092 KiB

Open AccessArticle

Ab-Initio Study of the Electronic and Magnetic Properties of Boron- and Nitrogen-Doped Penta-Graphene

by Chao Zhang, Yu Cao, Xing Dai, Xian-Yong Ding, Leilei Chen, Bing-Sheng Li and Dong-Qi Wang

Nanomaterials 2020, 10(4), 816; https://doi.org/10.3390/nano10040816 - 24 Apr 2020

Cited by 15 | Viewed by 3366

Abstract

First-principles calculations were performed to investigate the effects of boron/nitrogen dopant on the geometry, electronic structure and magnetic properties of the penta-graphene system. It was found that the electronic band gap of penta-graphene could be tuned and varied between 1.88 and 2.12 eV [...] Read more.

First-principles calculations were performed to investigate the effects of boron/nitrogen dopant on the geometry, electronic structure and magnetic properties of the penta-graphene system. It was found that the electronic band gap of penta-graphene could be tuned and varied between 1.88 and 2.12 eV depending on the type and location of the substitution. Moreover, the introduction of dopant could cause spin polarization and lead to the emergence of local magnetic moments. The main origin of the magnetic moment was analyzed and discussed by the examination of the spin-polarized charge density. Furthermore, the direction of charge transfer between the dopant and host atoms could be attributed to the competition between the charge polarization and the atomic electronegativity. Two charge-transfer mechanisms worked together to determine which atoms obtained electrons. These results provide the possibility of modifying penta-graphene by doping, making it suitable for future applications in the field of optoelectronic and magnetic devices. Full article

(This article belongs to the Section Nanocomposite Materials)

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16 pages, 2836 KiB

Open AccessFeature PaperArticle

Enhancing the Cellular Uptake and Antibacterial Activity of Rifampicin through Encapsulation in Mesoporous Silica Nanoparticles

by Paul Joyce, Hanna Ulmefors, Sajedeh Maghrebi, Santhni Subramaniam, Anthony Wignall, Silver Jõemetsa, Fredrik Höök and Clive A. Prestidge

Nanomaterials 2020, 10(4), 815; https://doi.org/10.3390/nano10040815 - 24 Apr 2020

Cited by 29 | Viewed by 5411

Abstract

An urgent demand exists for the development of novel delivery systems that efficiently transport antibacterial agents across cellular membranes for the eradication of intracellular pathogens. In this study, the clinically relevant poorly water-soluble antibiotic, rifampicin, was confined within mesoporous silica nanoparticles (MSN) to [...] Read more.

An urgent demand exists for the development of novel delivery systems that efficiently transport antibacterial agents across cellular membranes for the eradication of intracellular pathogens. In this study, the clinically relevant poorly water-soluble antibiotic, rifampicin, was confined within mesoporous silica nanoparticles (MSN) to investigate their ability to serve as an efficacious nanocarrier system against small colony variants of Staphylococcus aureus (SCV S. aureus) hosted within Caco-2 cells. The surface chemistry and particle size of MSN were varied through modifications during synthesis, where 40 nm particles with high silanol group densities promoted enhanced cellular uptake. Extensive biophysical analysis was performed, using quartz crystal microbalance with dissipation (QCM-D) and total internal reflection fluorescence (TIRF) microscopy, to elucidate the mechanism of MSN adsorption onto semi-native supported lipid bilayers (snSLB) and, thus, uncover potential cellular uptake mechanisms of MSN into Caco-2 cells. Such studies revealed that MSN with reduced silanol group densities were prone to greater particle aggregation on snSLB, which was expected to restrict endocytosis. MSN adsorption and uptake into Caco-2 cells correlated well with antibacterial efficacy against SCV S. aureus, with 40 nm hydrophilic particles triggering a ~2.5-log greater reduction in colony forming units, compared to the pure rifampicin. Thus, this study provides evidence for the potential to design silica nanocarrier systems with controlled surface chemistries that can be used to re-sensitise intracellular bacteria to antibiotics by delivering them to the site of infection. Full article

(This article belongs to the Special Issue Nanomedicine in Drug Delivery)

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20 pages, 10986 KiB

Open AccessArticle

Preparation and Characterization of Polypropylene/Carbon Nanotubes (PP/CNTs) Nanocomposites as Potential Strain Gauges for Structural Health Monitoring

by Bartolomeo Coppola, Luciano Di Maio, Loredana Incarnato and Jean-Marc Tulliani

Nanomaterials 2020, 10(4), 814; https://doi.org/10.3390/nano10040814 - 24 Apr 2020

Cited by 39 | Viewed by 5104

Abstract

Polypropylene/carbon nanotubes (PP/CNTs) nanocomposites with different CNTs concentrations (i.e., 1, 2, 3, 5 and 7 wt%) were prepared and tested as strain gauges for structures monitoring. Such sensors were embedded in cementitious mortar prisms and tested in 3-point bending mode recording impedance variation [...] Read more.

Polypropylene/carbon nanotubes (PP/CNTs) nanocomposites with different CNTs concentrations (i.e., 1, 2, 3, 5 and 7 wt%) were prepared and tested as strain gauges for structures monitoring. Such sensors were embedded in cementitious mortar prisms and tested in 3-point bending mode recording impedance variation at increasing load. First, thermal (differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA)), mechanical (tensile tests) and morphological (FE-SEM) properties of nanocomposites blends were assessed. Then, strain-sensing tests were carried out on PP/CNTs strips embedded in cementitious mortars. PP/CNTs nanocomposites blends with CNTs content of 1, 2 and 3 wt% did not show significant results because these concentrations are below the electrical percolation threshold (EPT). On the contrary, PP/CNTs nanocomposites with 5 and 7 wt% of CNTs showed interesting sensing properties. In particular, the best result was highlighted for the PP/CNT nanocomposite with 5 wt% CNTs for which an average gauge factor (GF) of approx. 1400 was measured. Moreover, load-unload cycles reported a good recovery of the initial impedance. Finally, a comparison with some literature results, in terms of GF, was done demonstrating the benefits deriving from the use of PP/CNTs strips as strain-gauges instead of using conductive fillers in the bulk matrix. Full article

(This article belongs to the Special Issue Carbon Nanoparticles for Strain Sensing and Damage Monitoring)

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17 pages, 7147 KiB

Open AccessArticle

Synergy Effect of Au and SiO₂ Modification on SnO₂ Sensor Properties in VOCs Detection in Humid Air

by Dayana Gulevich, Marina Rumyantseva, Evgeny Gerasimov, Nikolay Khmelevsky, Elena Tsvetkova and Alexander Gaskov

Nanomaterials 2020, 10(4), 813; https://doi.org/10.3390/nano10040813 - 23 Apr 2020

Cited by 18 | Viewed by 4536

Abstract

Nanocomposites based on Au- and SiO₂-modified SnO₂ were studied as sensitive materials for ethanol and benzene detection in dry (RH = 1%) and humid (RH = 20%) air. Modification of SnO₂ by amorphous SiO₂ (13 mol.%) was effectuated [...] Read more.

Nanocomposites based on Au- and SiO₂-modified SnO₂ were studied as sensitive materials for ethanol and benzene detection in dry (RH = 1%) and humid (RH = 20%) air. Modification of SnO₂ by amorphous SiO₂ (13 mol.%) was effectuated by hydrothermal synthesis; modification by Au nanoparticles (1 wt.%) was carried out via impregnation by citrate-stabilized Au sol. The composition of the samples was determined by X-ray fluorescent spectroscopy and energy-dispersive X-ray spectroscopy. The microstructure was characterized by XRD, HRTEM, and low-temperature nitrogen adsorption. The surface groups were investigated by XPS, TPR-H₂, and FTIR spectroscopy. DRIFT spectroscopy was performed to investigate the interaction between ethanol and the surface of the synthesized materials. Studies of the sensor properties have shown that in all cases the most sensitive is the SnO₂/SiO₂-Au nanocomposite. This material retains high sensitivity even in a humid atmosphere. The obtained results are discussed in terms of the synergistic effect of two modifiers (Au and SiO₂) in the formation of sensor properties of SnO₂/SiO₂–Au nanocomposites. Full article

(This article belongs to the Special Issue Nanostructured Sensors)

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12 pages, 9014 KiB

Open AccessArticle

Generating Silicon Nanofiber Clusters from Grinding Sludge by Millisecond Pulsed Laser Irradiation

by Ko Momoki, Kunimitsu Takahashi, Kyosuke Kobinata, Yoshikazu Kobayashi, Akihito Kawai and Jiwang Yan

Nanomaterials 2020, 10(4), 812; https://doi.org/10.3390/nano10040812 - 23 Apr 2020

Cited by 4 | Viewed by 2952

Abstract

Silicon nanofiber clusters were successfully generated by the irradiation of millisecond pulsed laser light on silicon sludge disposed from wafer back-grinding processes. It was found that the size, intensity, and growing speed of the laser-induced plume varied with the gas pressure, while the [...] Read more.

Silicon nanofiber clusters were successfully generated by the irradiation of millisecond pulsed laser light on silicon sludge disposed from wafer back-grinding processes. It was found that the size, intensity, and growing speed of the laser-induced plume varied with the gas pressure, while the size and morphology of the nanofibers were dependent on the laser pulse duration. The generated nanofibers were mainly amorphous with crystalline nanoparticles on their tips. The crystallinity and oxidation degree of the nanofibers depended on the preheating conditions of the silicon sludge. This study demonstrated the possibility of changing silicon waste into functional nanomaterials, which are possibly useful for fabricating high-performance lithium-ion battery electrodes. Full article

(This article belongs to the Special Issue Advances in Nanowire)

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21 pages, 5432 KiB

Open AccessFeature PaperArticle

Multi-Frequency Resonance Behaviour of a Si Fractal NEMS Resonator

by Vassil Tzanov, Jordi Llobet, Francesc Torres, Francesc Perez-Murano and Nuria Barniol

Nanomaterials 2020, 10(4), 811; https://doi.org/10.3390/nano10040811 - 23 Apr 2020

Cited by 4 | Viewed by 3932

Abstract

Novel Si-based nanosize mechanical resonator has been top-down fabricated. The shape of the resonating body has been numerically derived and consists of seven star-polygons that form a fractal structure. The actual resonator is defined by focused ion-beam implantation on a SOI wafer where [...] Read more.

Novel Si-based nanosize mechanical resonator has been top-down fabricated. The shape of the resonating body has been numerically derived and consists of seven star-polygons that form a fractal structure. The actual resonator is defined by focused ion-beam implantation on a SOI wafer where its 18 vertices are clamped to nanopillars. The structure is suspended over a 10 μm trench and has width of 12 μm. Its thickness of 0.040 μm is defined by the fabrication process and prescribes Young’s modulus of 76 GPa which is significantly lower than the value of the bulk material. The resonator is excited by the bottom Si-layer and the interferometric characterisation confirms broadband frequency response with quality factors of over 800 for several peaks between 2 MHz and 16 MHz. COMSOL FEM software has been used to vary material properties and residual stress in order to fit the eigenfrequencies of the model with the resonance peaks detected experimentally. Further use of the model shows how the symmetry of the device affects the frequency spectrum. Also, by using the FEM model, the possibility for an electrical read out of the device was tested. The experimental measurements and simulations proved that the device can resonate at many different excitation frequencies allowing multiple operational bands. The size, and the power needed for actuation are comparable with the ones of single beam resonator while the fractal structure allows much larger area for functionalisation. Full article

(This article belongs to the Special Issue Nanomaterials for the Advanced Manufacturing of Electronic Devices)

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23 pages, 7610 KiB

Open AccessArticle

Biological Safety and Biodistribution of Chitosan Nanoparticles

by Dmitry Sonin, Evgeniia Pochkaeva, Sergei Zhuravskii, Viktor Postnov, Dmitry Korolev, Lyubov Vasina, Daria Kostina, Daria Mukhametdinova, Irina Zelinskaya, Yury Skorik, Elena Naumysheva, Anna Malashicheva, Pavel Somov, Maria Istomina, Natalia Rubanova, Ilia Aleksandrov, Marina Vasyutina and Michael Galagudza

Nanomaterials 2020, 10(4), 810; https://doi.org/10.3390/nano10040810 - 23 Apr 2020

Cited by 52 | Viewed by 5411

Abstract

The effect of unmodified chitosan nanoparticles with a size of ~100 nm and a weakly positive charge on blood coagulation, metabolic activity of cultured cardiomyocytes, general toxicity, biodistribution, and reactive changes in rat organs in response to their single intravenous administration at doses [...] Read more.

The effect of unmodified chitosan nanoparticles with a size of ~100 nm and a weakly positive charge on blood coagulation, metabolic activity of cultured cardiomyocytes, general toxicity, biodistribution, and reactive changes in rat organs in response to their single intravenous administration at doses of 1, 2, and 4 mg/kg was studied. Chitosan nanoparticles (CNPs) have a small cytotoxic effect and have a weak antiplatelet and anticoagulant effect. Intravenous administration of CNPs does not cause significant hemodynamic changes, and 30 min after the CNPs administration, they mainly accumulate in the liver and lungs, without causing hemolysis and leukocytosis. The toxicity of chitosan nanoparticles was manifested in a dose-dependent short-term delay in weight gain with subsequent recovery, while in the 2-week observation period no signs of pain and distress were observed in rats. Granulomas found in the lungs and liver indicate slow biodegradation of chitosan nanoparticles. In general, the obtained results indicate a good tolerance of intravenous administration of an unmodified chitosan suspension in the studied dose range. Full article

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14 pages, 4861 KiB

Open AccessArticle

Investigation on Mn₃O₄ Coated Ru Nanoparticles for Partial Hydrogenation of Benzene towards Cyclohexene Production Using ZnSO₄, MnSO₄ and FeSO₄ as Reaction Additives

by Xingai Liu, Zhihao Chen, Haijie Sun, Lingxia Chen, Zhikun Peng and Zhongyi Liu

Nanomaterials 2020, 10(4), 809; https://doi.org/10.3390/nano10040809 - 23 Apr 2020

Cited by 5 | Viewed by 3600

Abstract

Mn₃O₄ coated Ru nanoparticles (Ru@Mn₃O₄) were synthesized via a precipitation-reduction-gel method. The prepared catalysts were evaluated for partial hydrogenation of benzene towards cyclohexene generation by applying ZnSO₄, MnSO₄ and FeSO₄ as reaction [...] Read more.

Mn₃O₄ coated Ru nanoparticles (Ru@Mn₃O₄) were synthesized via a precipitation-reduction-gel method. The prepared catalysts were evaluated for partial hydrogenation of benzene towards cyclohexene generation by applying ZnSO₄, MnSO₄ and FeSO₄ as reaction additives. The fresh and spent catalysts were thoroughly characterized by XRD, X ray fluorescence (XRF), XPS, TEM and N₂-physicalsorption in order to understand the promotion effect of Mn₃O₄ as the modifier as well as ZnSO₄, MnSO₄ and FeSO₄ as reaction additives. It was found that 72.0% of benzene conversion and 79.2% of cyclohexene selectivity was achieved after 25 min of reaction time over Ru@Mn₃O₄ with a molar ratio of Mn/Ru being 0.46. This can be rationalized in terms of the formed (Zn(OH)₂)₃(ZnSO₄)(H₂O)₃ on the Ru surface from the reaction between Mn₃O₄ and the added ZnSO₄. Furthermore, Fe²⁺ and Fe³⁺ compounds could be generated and adsorbed on the surface of Ru@Mn₃O₄ when FeSO₄ is applied as a reaction additive. The most electrons were transferred from Ru to Fe, resulting in that lowest benzene conversion of 1.5% and the highest cyclohexene selectivity of 92.2% after 25 min of catalytic experiment. On the other hand, by utilizing MnSO₄ as an additive, no electrons transfer was observed between Ru and Mn, which lead to the complete hydrogenation of benzene towards cyclohexane within 5 min. In comparison, moderate amount of electrons were transferred from Ru to Zn²⁺ in (Zn(OH)₂)₃(ZnSO₄)(H₂O)₃ when ZnSO₄ is used as a reaction additive, and the highest cyclohexene yield of 57.0% was obtained within 25 min of reaction time. Full article

(This article belongs to the Special Issue Catalysis by Metal-Oxide Nanostructures)

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18 pages, 4875 KiB

Open AccessArticle

3-Dimensional Porous Carbon with High Nitrogen Content Obtained from Longan Shell and Its Excellent Performance for Aqueous and All-Solid-State Supercapacitors

by Yuhao Liu, Xiaoxiao Qu, Guangxu Huang, Baolin Xing, Fengmei Zhang, Binbin Li, Chuanxiang Zhang and Yijun Cao

Nanomaterials 2020, 10(4), 808; https://doi.org/10.3390/nano10040808 - 23 Apr 2020

Cited by 30 | Viewed by 4059

Abstract

Three-dimensional porous carbon is considered as an ideal electrode material for supercapacitors (SCs) applications owing to its good conductivity, developed pore structure, and excellent connectivity. Herein, using longan shell as precursor, 3-dimensional porous carbon with abundant and interconnected pores and moderate heteroatoms were [...] Read more.

Three-dimensional porous carbon is considered as an ideal electrode material for supercapacitors (SCs) applications owing to its good conductivity, developed pore structure, and excellent connectivity. Herein, using longan shell as precursor, 3-dimensional porous carbon with abundant and interconnected pores and moderate heteroatoms were obtained via simple carbonization and potassium hydroxide (KOH) activation treatment. The electrochemical performances of obtained 3-dimensional porous carbon were investigated as electrode materials in symmetric SCs with aqueous and solid electrolytes. The optimized material that is named after longan shell 3-dimensional porous carbon 800 (LSPC800) possesses high porosity (1.644 cm³ g⁻¹) and N content (1.14 at %). In the three-electrode measurement, the LSPC800 displays an excellent capacitance value of 359 F g⁻¹. Besides, the LSPC800 also achieves splendid specific capacitance (254 F g⁻¹) in the two electrode system, while the fabricated SC employing 1 M Li₂SO₄ as electrolyte acquires ultrahigh power density (15930.38 W kg⁻¹). Most importantly, LSPC800 electrodes are further applied into the SC adopting the KOH/polyvinyl alcohol (PVA) gel electrolyte, which reaches up to an outstanding capacitance of 313 F g⁻¹ at 0.5 A g⁻¹. In addition, for the all-solid-state SC, its rate capability at 50 A g⁻¹ is 72.73% and retention at the 10,000th run is 93.64%. Evidently, this work is of great significance to the simple fabrication of 3-dimensional porous carbon and further opens up a way of improving the value-added utilization of biomass materials, as well as proving that the biomass porous carbons have immense potential for high-performance SCs application. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanomaterials for Energy Storage)

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15 pages, 2942 KiB

Open AccessArticle

The Effect of Different Oxygen Surface Functionalization of Carbon Nanotubes on the Electrical Resistivity and Strain Sensing Function of Cement Pastes

by B. Del Moral, I. Martín Gullón, R. Navarro, O. Galao, F.J. Baeza, E. Zornoza, B. Calderón, I. Rodríguez, N. Arnaiz, M.D. Romero Sánchez and P. Garcés

Nanomaterials 2020, 10(4), 807; https://doi.org/10.3390/nano10040807 - 23 Apr 2020

Cited by 14 | Viewed by 3303

Abstract

Different studies in the literature indicate the effectiveness of CNTs as reinforcing materials in cement–matrix composites due to their high mechanical strength. Nevertheless, their incorporation into cement presents some difficulties due to their tendency to agglomerate, yielding a non-homogeneous dispersion in the paste [...] Read more.

Different studies in the literature indicate the effectiveness of CNTs as reinforcing materials in cement–matrix composites due to their high mechanical strength. Nevertheless, their incorporation into cement presents some difficulties due to their tendency to agglomerate, yielding a non-homogeneous dispersion in the paste mix that results in a poor cement–CNTs interaction. This makes the surface modification of the CNTs by introducing functional groups on the surface necessary. In this study, three different treatments for incorporating polar oxygen functional groups onto the surface of carbon nanotubes have been carried out, with the objective of evaluating the influence of the type and oxidation degree on the mechanical and electrical properties and in strain-sensing function of cement pastes containing CNTs. One treatment is in liquid phase (surface oxidation with HNO₃/H₂SO₄), the second is in gas phase (O₃ treatment at 25 and 160 °C), and a third is a combination of gas-phase O₃ treatment plus NaOH liquid phase. The electrical conductivity of cement pastes increased with O₃- and O₃-NaOH-treated CNTs with respect to non-treated ones. Furthermore, the oxygen functionalization treatments clearly improve the strain sensing performance of the CNT-cement pastes, particularly in terms of the accuracy of the linear correlation between the resistance and the stress, as well as the increase in the gage factor from 28 to 65. Additionally, the incorporation of either non-functionalized or functionalized CNTs did not produce any significant modification of the mechanical properties of CNTs. Therefore, the functionalization of CNTs favours the de-agglomeration of CNTs in the cement matrix and consequently, the electrical conductivity, without affecting the mechanical behaviour. Full article

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10 pages, 2077 KiB

Open AccessArticle

Facile Synthesis of Solution-Processed Silica and Polyvinyl Phenol Hybrid Dielectric for Flexible Organic Transistors

by Xiong Chen, Yu Zhang, Xiangfeng Guan and Hao Zhang

Nanomaterials 2020, 10(4), 806; https://doi.org/10.3390/nano10040806 - 23 Apr 2020

Cited by 2 | Viewed by 2527

Abstract

A high-quality dielectric layer is essential for organic thin-film transistors (OTFTs) operated at a low-power consumption level. In this study, a facile improved technique for the synthesis of solution-processed silica is proposed. By optimizing the synthesis and processing technique fewer pores were found [...] Read more.

A high-quality dielectric layer is essential for organic thin-film transistors (OTFTs) operated at a low-power consumption level. In this study, a facile improved technique for the synthesis of solution-processed silica is proposed. By optimizing the synthesis and processing technique fewer pores were found on the surface of the film, particularly no large holes were observable after improving the annealing process, and the improved solution–gelation (sol–gel) SiO_x dielectric achieved a higher breakdown strength (1.6 MV/cm) and lower leakage current density (10⁻⁸ A/cm² at 1.5 MV/cm). Consequently, a pentacene based OTFT with a high field effect mobility (~1.8 cm²/Vs), a low threshold voltage (−1.7 V), a steeper subthreshold slope (~0.4 V/dec) and a relatively high on/off ratio (~10⁵) was fabricated by applying a hybrid gate insulator which consisted of improved sol–gel SiO_x and polyvinyl phenol (PVP). This could be ascribed to both the high k of SiO_x and the smoother, hydrophobic dielectric surface with low trap density, which was proved by atomic force microscopy (AFM) and a water contact angle test, respectively. Additionally, we systematically studied and evaluated the stability of devices in the compressed state. The devices based on dielectric fabricated by conventional sol–gel processes were more susceptible to the curvature. While the improved device presented an excellent mechanic strength, it could still function at the higher bending compression without a significant degradation in performance. Thus, this solution-process technology provides an effective approach to fabricate high-quality dielectric and offers great potential for low-cost, fast and portable organic electronic applications. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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14 pages, 5941 KiB

Open AccessArticle

Noble Metal-Free TiO₂-Coated Carbon Nitride Layers for Enhanced Visible Light-Driven Photocatalysis

by Bo Zhang, Xiangfeng Peng and Zhao Wang

Nanomaterials 2020, 10(4), 805; https://doi.org/10.3390/nano10040805 - 23 Apr 2020

Cited by 15 | Viewed by 3401

Abstract

Composites of g-C₃N₄/TiO₂ were one-step prepared using electron impact with dielectric barrier discharge (DBD) plasma as the electron source. Due to the low operation temperature, TiO₂ by the plasma method shows higher specific surface area and smaller [...] Read more.

Composites of g-C₃N₄/TiO₂ were one-step prepared using electron impact with dielectric barrier discharge (DBD) plasma as the electron source. Due to the low operation temperature, TiO₂ by the plasma method shows higher specific surface area and smaller particle size than that prepared via conventional calcination. Most interestingly, electron impact produces more oxygen vacancy on TiO₂, which facilitates the recombination and formation of heterostructure of g-C₃N₄/TiO₂. The composites have higher light absorption capacity and lower charge recombination efficiency. g-C₃N₄/TiO₂ by plasma can produce hydrogen at a rate of 219.9 μmol·g⁻¹·h⁻¹ and completely degrade Rhodamine B (20mg·L⁻¹) in two hours. Its hydrogen production rates were 3 and 1.5 times higher than that by calcination and pure g-C₃N₄, respectively. Electron impact, ozone and oxygen radical also play key roles in plasma preparation. Plasma has unique advantages in metal oxides defect engineering and the preparation of heterostructured composites with prospective applications as photocatalysts for pollutant degradation and water splitting. Full article

(This article belongs to the Special Issue 10th Anniversary of Nanomaterials—Recent Advances in Nanocomposite Thin Films and 2D Materials)

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14 pages, 3489 KiB

Open AccessArticle

A Nano-Rattle SnO₂@carbon Composite Anode Material for High-Energy Li-ion Batteries by Melt Diffusion Impregnation

by Sivarajakumar Maharajan, Nam Hee Kwon, Pierre Brodard and Katharina M. Fromm

Nanomaterials 2020, 10(4), 804; https://doi.org/10.3390/nano10040804 - 22 Apr 2020

Cited by 10 | Viewed by 3462

Abstract

The huge volume expansion in Sn-based alloy anode materials (up to 360%) leads to a dramatic mechanical stress and breaking of particles, resulting in the loss of conductivity and thereby capacity fading. To overcome this issue, SnO₂@C nano-rattle composites based on [...] Read more.

The huge volume expansion in Sn-based alloy anode materials (up to 360%) leads to a dramatic mechanical stress and breaking of particles, resulting in the loss of conductivity and thereby capacity fading. To overcome this issue, SnO₂@C nano-rattle composites based on <10 nm SnO₂ nanoparticles in and on porous amorphous carbon spheres were synthesized using a silica template and tin melting diffusion method. Such SnO₂@C nano-rattle composite electrodes provided two electrochemical processes: a partially reversible process of the SnO₂ reduction to metallic Sn at 0.8 V vs. Li⁺/Li and a reversible process of alloying/dealloying of Li_xSn_y at 0.5 V vs. Li⁺/Li. Good performance could be achieved by controlling the particle sizes of SnO₂ and carbon, the pore size of carbon, and the distribution of SnO₂ nanoparticles on the carbon shells. Finally, the areal capacity of SnO₂@C prepared by the melt diffusion process was increased due to the higher loading of SnO₂ nanoparticles into the hollow carbon spheres, as compared with Sn impregnation by a reducing agent. Full article

(This article belongs to the Section Energy and Catalysis)

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21 pages, 5049 KiB

Open AccessReview

Conductive Atomic Force Microscopy of Semiconducting Transition Metal Dichalcogenides and Heterostructures

by Filippo Giannazzo, Emanuela Schilirò, Giuseppe Greco and Fabrizio Roccaforte

Nanomaterials 2020, 10(4), 803; https://doi.org/10.3390/nano10040803 - 22 Apr 2020

Cited by 36 | Viewed by 9324

Abstract

Semiconducting transition metal dichalcogenides (TMDs) are promising materials for future electronic and optoelectronic applications. However, their electronic properties are strongly affected by peculiar nanoscale defects/inhomogeneities (point or complex defects, thickness fluctuations, grain boundaries, etc.), which are intrinsic of these materials or introduced during [...] Read more.

Semiconducting transition metal dichalcogenides (TMDs) are promising materials for future electronic and optoelectronic applications. However, their electronic properties are strongly affected by peculiar nanoscale defects/inhomogeneities (point or complex defects, thickness fluctuations, grain boundaries, etc.), which are intrinsic of these materials or introduced during device fabrication processes. This paper reviews recent applications of conductive atomic force microscopy (C-AFM) to the investigation of nanoscale transport properties in TMDs, discussing the implications of the local phenomena in the overall behavior of TMD-based devices. Nanoscale resolution current spectroscopy and mapping by C-AFM provided information on the Schottky barrier uniformity and shed light on the mechanisms responsible for the Fermi level pinning commonly observed at metal/TMD interfaces. Methods for nanoscale tailoring of the Schottky barrier in MoS₂ for the realization of ambipolar transistors are also illustrated. Experiments on local conductivity mapping in monolayer MoS₂ grown by chemical vapor deposition (CVD) on SiO₂ substrates are discussed, providing a direct evidence of the resistance associated to the grain boundaries (GBs) between MoS₂ domains. Finally, C-AFM provided an insight into the current transport phenomena in TMD-based heterostructures, including lateral heterojunctions observed within Mo_xW_1–xSe₂ alloys, and vertical heterostructures made by van der Waals stacking of different TMDs (e.g., MoS₂/WSe₂) or by CVD growth of TMDs on bulk semiconductors. Full article

(This article belongs to the Special Issue Nanoscale Electrical Characterization of Low Dimensional Materials for Electronics)

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12 pages, 1077 KiB

Open AccessCommunication

Can Nanotechnology and Materials Science Help the Fight against SARS-CoV-2?

by Maria Chiara Sportelli, Margherita Izzi, Ekaterina A. Kukushkina, Syed Imdadul Hossain, Rosaria Anna Picca, Nicoletta Ditaranto and Nicola Cioffi

Nanomaterials 2020, 10(4), 802; https://doi.org/10.3390/nano10040802 - 21 Apr 2020

Cited by 210 | Viewed by 22921

Abstract

Since 2004, we have been developing nanomaterials with antimicrobial properties, the so-called nanoantimicrobials. When the coronavirus disease 2019 (COVID-19) emerged, we started investigating new and challenging routes to nanoantivirals. The two fields have some important points of contact. We would like to share [...] Read more.

Since 2004, we have been developing nanomaterials with antimicrobial properties, the so-called nanoantimicrobials. When the coronavirus disease 2019 (COVID-19) emerged, we started investigating new and challenging routes to nanoantivirals. The two fields have some important points of contact. We would like to share with the readership our vision of the role a (nano)materials scientist can play in the fight against the COVID-19 pandemic. As researchers specifically working on surfaces and nanomaterials, in this letter we underline the importance of nanomaterial-based technological solutions in several aspects of the fight against the virus. While great resources are understandably being dedicated to treatment and diagnosis, more efforts could be dedicated to limit the virus spread. Increasing the efficacy of personal protection equipment, developing synergistic antiviral coatings, are only two of the cases discussed. This is not the first nor the last pandemic: our nanomaterials community may offer several technological solutions to challenge the ongoing and future global health emergencies. Readers’ feedback and suggestions are warmly encouraged. Full article

(This article belongs to the Section Biology and Medicines)

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12 pages, 2907 KiB

Open AccessArticle

Peculiarities of the Crystal Structure Evolution of BiFeO₃–BaTiO₃ Ceramics across Structural Phase Transitions

by Dmitry V. Karpinsky, Maxim V. Silibin, Sergei V. Trukhanov, Alex V. Trukhanov, Alexander L. Zhaludkevich, Siarhei I. Latushka, Dmitry V. Zhaludkevich, Vladimir A. Khomchenko, Denis O. Alikin, Alexander S. Abramov, Tomasz Maniecki, Waldemar Maniukiewicz, Martin Wolff, Volker Heitmann and Andrei L. Kholkin

Nanomaterials 2020, 10(4), 801; https://doi.org/10.3390/nano10040801 - 21 Apr 2020

Cited by 69 | Viewed by 4804

Abstract

Evolution of the crystal structure of ceramics BiFeO₃–BaTiO₃ across the morphotropic phase boundary was analyzed using the results of macroscopic measuring techniques such as X-ray diffraction, differential scanning calorimetry, and differential thermal analysis, as well as the data obtained by [...] Read more.

Evolution of the crystal structure of ceramics BiFeO₃–BaTiO₃ across the morphotropic phase boundary was analyzed using the results of macroscopic measuring techniques such as X-ray diffraction, differential scanning calorimetry, and differential thermal analysis, as well as the data obtained by local scale methods of scanning probe microscopy. The obtained results allowed to specify the concentration and temperature regions of the single phase and phase coexistent regions as well as to clarify a modification of the structural parameters across the rhombohedral–cubic phase boundary. The structural data show unexpected strengthening of structural distortion specific for the rhombohedral phase, which occurs upon dopant concentration and temperature-driven phase transitions to the cubic phase. The obtained results point to the non-monotonous character of the phase evolution, which is specific for metastable phases. The compounds with metastable structural state are characterized by enhanced sensitivity to external stimuli, which significantly expands the perspectives of their particular use. Full article

(This article belongs to the Special Issue Oxide Magnetics)

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1 pages, 177 KiB

Open AccessCorrection

Correction: Haj-Khlifa, S., et al. Polyol Process Coupled to Cold Plasma as a New and Efficient Nanohydride Processing Method: Nano-Ni₂H as a Case Study. Nanomaterials 2020, 10, 136

by Sonia Haj-Khlifa, Sophie Nowak, Patricia Beaunier, Patricia De Rango, Michaël Redolfi and Souad Ammar-Merah

Nanomaterials 2020, 10(4), 800; https://doi.org/10.3390/nano10040800 - 21 Apr 2020

Viewed by 2158

Abstract

The authors wish to make the following corrections to this paper [...] Full article

14 pages, 3893 KiB

Open AccessArticle

Spherical Polyelectrolyte Brushes as Templates to Prepare Hollow Silica Spheres Encapsulating Metal Nanoparticles

by Qingsong Yang, Li Li, Fang Zhao, Yunwei Wang, Zhishuang Ye, Chen Hua, Zhiyong Liu, Klemen Bohinc and Xuhong Guo

Nanomaterials 2020, 10(4), 799; https://doi.org/10.3390/nano10040799 - 21 Apr 2020

Cited by 21 | Viewed by 4367

Abstract

Integrating hollow silica spheres with metal nanoparticles to fabricate multifunctional hybrid materials has attracted increasing attention in catalysis, detection, and drug delivery. Here, we report a simple and general method to prepare hollow silica spheres encapsulating silver nanoparticles (Ag@SiO₂) based on [...] Read more.

Integrating hollow silica spheres with metal nanoparticles to fabricate multifunctional hybrid materials has attracted increasing attention in catalysis, detection, and drug delivery. Here, we report a simple and general method to prepare hollow silica spheres encapsulating silver nanoparticles (Ag@SiO₂) based on spherical polyelectrolyte brushes (SPB), which consist of a polystyrene core and densely grafted poly (acrylic acid) (PAA) chains. SPB were firstly used as nanoreactors to generate silver nanoparticles in situ and then used as sacrificial templates to prepare hybrid hollow silica spheres. The resulted Ag@SiO₂ composites exhibit high catalytic activity and good reusability for the reduction of 4-nitrophenol to 4-aminophenol by NaBH₄. More importantly, this developed approach can be extended to the encapsulation of other metal nanoparticles such as gold nanoparticles into the hollow silica spheres. This work demonstrates that SPB are promising candidates for the preparation of hollow spheres with encapsulated metal nanoparticles and the resulted hybrid spheres show great potential applications in catalysis. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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13 pages, 3579 KiB

Open AccessArticle

Unraveling Origins of EPR Spectrum in Graphene Oxide Quantum Dots

by Krzysztof Tadyszak, Andrzej Musiał, Adam Ostrowski and Jacek K. Wychowaniec

Nanomaterials 2020, 10(4), 798; https://doi.org/10.3390/nano10040798 - 21 Apr 2020

Cited by 14 | Viewed by 4848

Abstract

Carbon nanostructures are utilized in a plethora of applications ranging from biomedicine to electronics. Particularly interesting are carbon nanostructured quantum dots that can be simultaneously used for bimodal therapies with both targeting and imaging capabilities. Here, magnetic and optical properties of graphene oxide [...] Read more.

Carbon nanostructures are utilized in a plethora of applications ranging from biomedicine to electronics. Particularly interesting are carbon nanostructured quantum dots that can be simultaneously used for bimodal therapies with both targeting and imaging capabilities. Here, magnetic and optical properties of graphene oxide quantum dots (GOQDs) prepared by the top-down technique from graphene oxide and obtained using the Hummers’ method were studied. Graphene oxide was ultra-sonicated, boiled in HNO₃, ultra-centrifuged, and finally filtrated, reaching a mean flake size of ~30 nm with quantum dot properties. Flake size distributions were obtained from scanning electron microscopy (SEM) images after consecutive preparation steps. Energy-dispersive X-ray (EDX) confirmed that GOQDs were still oxidized after the fabrication procedure. Magnetic and photoluminescence measurements performed on the obtained GOQDs revealed their paramagnetic behavior and broad range optical photoluminescence around 500 nm, with magnetic moments of 2.41 µ_B. Finally, electron paramagnetic resonance (EPR) was used to separate the unforeseen contributions and typically not taken into account metal contaminations, and radicals from carbon defects. This study contributes to a better understanding of magnetic properties of carbon nanostructures, which could in the future be used for the design of multimodal imaging agents. Full article

(This article belongs to the Special Issue Nanocarbon Based Materials)

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13 pages, 5058 KiB

Open AccessArticle

Fabrication and Characterization of a Novel Composite Magnetic Photocatalyst β-Bi₂O₃/BiVO₄/Mn_xZn_1−xFe₂O₄ for Rhodamine B Degradation under Visible Light

by Yong Cheng, Yahan Yang, Zao Jiang, Longjun Xu and Chenglun Liu

Nanomaterials 2020, 10(4), 797; https://doi.org/10.3390/nano10040797 - 21 Apr 2020

Cited by 12 | Viewed by 2736

Abstract

β-Bi₂O₃/BiVO₄/Mn_xZn_1−xFe₂O₄ (BV/MZF) composite magnetic photocatalyst was first synthesized using the hydrothermal and calcination method. BV/MZF was a mesoporous material with most probable pore size and specific surface area of 18 [...] Read more.

β-Bi₂O₃/BiVO₄/Mn_xZn_1−xFe₂O₄ (BV/MZF) composite magnetic photocatalyst was first synthesized using the hydrothermal and calcination method. BV/MZF was a mesoporous material with most probable pore size and specific surface area of 18 nm and 17.84 m²/g, respectively. Due to its high saturation magnetization (2.67 emu/g), the BV/MZF composite can be easily separated and recovered from solution under an external magnetic field. The results of photo-decomposition experiments show that the decomposition rate of Rhodamine B (RhB) by BV/MZF can reach 92.6% in 3 h under visible light. After three cycles, BV/MZF can still maintain structural stability and excellent pollutant degradation effect. In addition, analysis of the photocatalytic mechanism of BV/MZF for RhB shows that the p-n heterojunction formed in BV/MZF plays a vital role in its photocatalytic performance. This work has potential application in the future for solving environmental pollution. Full article

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14 pages, 2327 KiB

Open AccessArticle

Temperature Effect on Capillary Flow Dynamics in 1D Array of Open Nanotextured Microchannels Produced by Femtosecond Laser on Silicon

by Ranran Fang, Hongbo Zhu, Zekai Li, Xiaohui Zhu, Xianhang Zhang, Zhiyu Huang, Ke Li, Wensheng Yan, Yi Huang, Valeriy S. Maisotsenko and Anatoliy Y. Vorobyev

Nanomaterials 2020, 10(4), 796; https://doi.org/10.3390/nano10040796 - 21 Apr 2020

Cited by 13 | Viewed by 3186

Abstract

Capillary flow of water in an array of open nanotextured microgrooves fabricated by femtosecond laser processing of silicon is studied as a function of temperature using high-speed video recording. In a temperature range of 23–80 °C, the produced wicking material provides extremely fast [...] Read more.

Capillary flow of water in an array of open nanotextured microgrooves fabricated by femtosecond laser processing of silicon is studied as a function of temperature using high-speed video recording. In a temperature range of 23–80 °C, the produced wicking material provides extremely fast liquid flow with a maximum velocity of 37 cm/s in the initial spreading stage prior to visco-inertial regime. The capillary performance of the material enhances with increasing temperature in the inertial, visco-inertial, and partially in Washburn flow regimes. The classic universal Washburn’s regime is observed at all studied temperatures, giving the evidence of its universality at high temperatures as well. The obtained results are of great significance for creating capillary materials for applications in cooling of electronics, energy harvesting, enhancing the critical heat flux of industrial boilers, and Maisotsenko cycle technologies. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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15 pages, 3750 KiB

Open AccessArticle

Enhanced Solar Light Photocatalytic Activity of Ag Doped TiO₂–Ag₃PO₄ Composites

by Abdessalem Hamrouni, Hanen Azzouzi, Ali Rayes, Leonardo Palmisano, Riccardo Ceccato and Francesco Parrino

Nanomaterials 2020, 10(4), 795; https://doi.org/10.3390/nano10040795 - 21 Apr 2020

Cited by 45 | Viewed by 3971

Abstract

Composites comprised of Ag₃PO₄ and bare TiO₂ (TiO₂@Ag₃PO₄) or silver doped TiO₂ (Ag@TiO₂–Ag₃PO₄) have been synthesized by coupling sol–gel and precipitation methods. For the sake of [...] Read more.

Composites comprised of Ag₃PO₄ and bare TiO₂ (TiO₂@Ag₃PO₄) or silver doped TiO₂ (Ag@TiO₂–Ag₃PO₄) have been synthesized by coupling sol–gel and precipitation methods. For the sake of comparison, also the bare components have been similarly prepared. All the samples have been characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR), photoelectrochemical measurements, and specific surface area (SSA) analysis. The optoelectronic and structural features of the samples have been related to their photocatalytic activity for the degradation of 4–nitrophenol under solar and UV light irradiation. Coupling Ag₃PO₄ with silver doped TiO₂ mitigates photocorrosion of the Ag₃PO₄ counterpart, and remarkably improves the photocatalytic activity under solar light irradiation with respect to the components, to the TiO₂–Ag₃PO₄ sample, and to the benchmark TiO₂ Evonik P25. These features open the route to future applications of this material in the field of environmental remediation. Full article

(This article belongs to the Special Issue Nanocontainers, Nano-Adsorbents, and Their Polymer Composites)

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9 pages, 10880 KiB

Open AccessArticle

Induced Topological Superconductivity in a BiSbTeSe₂-Based Josephson Junction

by Bob de Ronde, Chuan Li, Yingkai Huang and Alexander Brinkman

Nanomaterials 2020, 10(4), 794; https://doi.org/10.3390/nano10040794 - 21 Apr 2020

Cited by 12 | Viewed by 4614

Abstract

A 4

π

-periodic supercurrent through a Josephson junction can be a consequence of the presence of Majorana bound states. A systematic study of the radio frequency response for several temperatures and frequencies yields a concrete protocol for examining the 4

π

-periodic [...] Read more.

A 4

π

-periodic supercurrent through a Josephson junction can be a consequence of the presence of Majorana bound states. A systematic study of the radio frequency response for several temperatures and frequencies yields a concrete protocol for examining the 4

π

-periodic contribution to the supercurrent. This work also reports the observation of a 4

π

-periodic contribution to the supercurrent in BiSbTeSe

_{2}

-based Josephson junctions. As a response to irradiation by radio frequency waves, the junctions showed an absence of the first Shapiro step. At high irradiation power, a qualitative correspondence to a model including a 4

π

-periodic component to the supercurrent is found. Full article

(This article belongs to the Special Issue Superconductivity in Nanoscaled Systems)

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11 pages, 3331 KiB

Open AccessArticle

Study of Silicon Nitride Inner Spacer Formation in Process of Gate-all-around Nano-Transistors

by Junjie Li, Yongliang Li, Na Zhou, Wenjuan Xiong, Guilei Wang, Qingzhu Zhang, Anyan Du, Jianfeng Gao, Zhenzhen Kong, Hongxiao Lin, Jinjuan Xiang, Chen Li, Xiaogen Yin, Xiaolei Wang, Hong Yang, Xueli Ma, Jianghao Han, Jing Zhang, Tairan Hu, Zhe Cao, Tao Yang, Junfeng Li, Huaxiang Yin, Huilong Zhu, Jun Luo, Wenwu Wang and Henry H. Radamson Show full author list Hide full author list

Nanomaterials 2020, 10(4), 793; https://doi.org/10.3390/nano10040793 - 20 Apr 2020

Cited by 35 | Viewed by 13113

Abstract

Stacked SiGe/Si structures are widely used as the units for gate-all-around nanowire transistors (GAA NWTs) which are a promising candidate beyond fin field effective transistors (FinFETs) technologies in near future. These structures deal with a several challenges brought by the shrinking of device [...] Read more.

Stacked SiGe/Si structures are widely used as the units for gate-all-around nanowire transistors (GAA NWTs) which are a promising candidate beyond fin field effective transistors (FinFETs) technologies in near future. These structures deal with a several challenges brought by the shrinking of device dimensions. The preparation of inner spacers is one of the most critical processes for GAA nano-scale transistors. This study focuses on two key processes: inner spacer film conformal deposition and accurate etching. The results show that low pressure chemical vapor deposition (LPCVD) silicon nitride has a good film filling effect; a precise and controllable silicon nitride inner spacer structure is prepared by using an inductively coupled plasma (ICP) tool and a new gas mixtures of CH₂F₂/CH₄/O₂/Ar. Silicon nitride inner spacer etch has a high etch selectivity ratio, exceeding 100:1 to Si and more than 30:1 to SiO₂. High anisotropy with an excellent vertical/lateral etch ratio exceeding 80:1 is successfully demonstrated. It also provides a solution to the key process challenges of nano-transistors beyond 5 nm node. Full article

(This article belongs to the Special Issue Plasma Based Nanomaterials and Their Applications)

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15 pages, 4903 KiB

Open AccessArticle

Grafting Thin Layered Graphene Oxide onto the Surface of Nonwoven/PVDF-PAA Composite Membrane for Efficient Dye and Macromolecule Separations

by Febri Baskoro, Selvaraj Rajesh Kumar and Shingjiang Jessie Lue

Nanomaterials 2020, 10(4), 792; https://doi.org/10.3390/nano10040792 - 20 Apr 2020

Cited by 17 | Viewed by 3773

Abstract

This study investigates the permeance and rejection efficiencies of different dyes (Rhodamine B and methyl orange), folic acid and a protein (bovine serum albumin) using graphene oxide composite membrane. The ultrathin separation layer of graphene oxide (thickness of 380 nm) was successfully deposited [...] Read more.

This study investigates the permeance and rejection efficiencies of different dyes (Rhodamine B and methyl orange), folic acid and a protein (bovine serum albumin) using graphene oxide composite membrane. The ultrathin separation layer of graphene oxide (thickness of 380 nm) was successfully deposited onto porous polyvinylidene fluoride-polyacrylic acid intermediate layer on nonwoven support layer using vacuum filtration. The graphene oxide addition in the composite membrane caused an increased hydrophilicity and negative surface charge than those of the membrane without graphene oxide. In the filtration process using a graphene oxide composite membrane, the permeance values of pure water, dyes, folic acid and bovine serum albumin molecules were more severely decreased (by two orders of magnitude) than those of the nonwoven/polyvinylidene fluoride-polyacrylic acid composite membrane. However, the rejection efficiency of the graphene oxide composite was significantly improved in cationic Rhodamine B (from 9% to 80.3%) and anionic methyl orange (from 28.3% to 86.6%) feed solutions. The folic acid and bovine serum albumin were nearly completely rejected from solutions using either nonwoven/polyvinylidene fluoride-polyacrylic acid or nonwoven/polyvinylidene fluoride-polyacrylic acid/graphene oxide composite membrane, but the latter possessed anti-fouling property against the protein molecules. The separation mechanism in nonwoven/polyvinylidene fluoride-polyacrylic acid membrane includes the Donnan exclusion effect (for smaller-than-pore-size solutes) and sieving mechanism (for larger solutes). The sieving mechanism governs the filtration behavior in the nonwoven/polyvinylidene fluoride-polyacrylic acid/graphene oxide composite membrane. Full article

(This article belongs to the Section Nanocomposite Materials)

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20 pages, 5873 KiB

Open AccessArticle

Cerium Dioxide Nanoparticles as Smart Carriers for Self-Healing Coatings

by Sehrish Habib, Eman Fayyad, Muddasir Nawaz, Adnan Khan, Rana A. Shakoor, Ramazan Kahraman and Aboubakr Abdullah

Nanomaterials 2020, 10(4), 791; https://doi.org/10.3390/nano10040791 - 20 Apr 2020

Cited by 57 | Viewed by 5802

Abstract

The utilization of self-healing cerium dioxide nanoparticles (CeO₂), modified with organic corrosion inhibitors (dodecylamine (DDA) and n-methylthiourea (NMTU)), in epoxy coating is an efficient strategy for enhancing the protection of the epoxy coating and increasing its lifetime. Fourier transform infrared (FTIR) [...] Read more.

The utilization of self-healing cerium dioxide nanoparticles (CeO₂), modified with organic corrosion inhibitors (dodecylamine (DDA) and n-methylthiourea (NMTU)), in epoxy coating is an efficient strategy for enhancing the protection of the epoxy coating and increasing its lifetime. Fourier transform infrared (FTIR) spectroscopy analysis was used to confirm the loading and presence of inhibitors in the nanoparticles. Thermal gravimetric analysis (TGA) measurement studies revealed the amount of 25% and 29.75% w/w for NMTU and DDA in the nanoparticles, respectively. The pH sensitive and self-release behavior of modified CeO₂ nanoparticles is confirmed through UV-vis spectroscopy and Zeta potential. It was observed, through scanning electron microscopy (SEM), that a protective layer had been formed on the defect site separating the steel surface from the external environment and healed the artificially created scratch. This protective film played a vital role in the corrosion inhibition of steel by preventing the aggressiveness of Cl⁻ in the solution. Electrochemical impedance spectroscopy (EIS) measurements exhibited the exceptional corrosion inhibition efficiency, reaching 99.8% and 95.7% for the modified coating with DDA and NMTU, respectively, after five days of immersion time. Full article

(This article belongs to the Special Issue Functional Inorganic Nanomaterials)

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15 pages, 3638 KiB

Open AccessArticle

Acoustic Multi-Detection of Gliadin Using QCM Crystals Patterned with Controlled Sectors of TEM Grid and Annealed Nanoislands on Gold Electrode

by Giuliocesare Casari Bariani, Lan Zhou, Simone Poggesi, Rakesh Mittapalli, Marisa Manzano and Rodica Elena Ionescu

Nanomaterials 2020, 10(4), 790; https://doi.org/10.3390/nano10040790 - 20 Apr 2020

Cited by 3 | Viewed by 2862

Abstract

Celiac diseases are a group of gluten ingestion-correlated pathologies that are widespread and, in some cases, very dangerous for human health. The only effective treatment is the elimination of gluten from the diet throughout life. Nowadays, the food industries are very interested in [...] Read more.

Celiac diseases are a group of gluten ingestion-correlated pathologies that are widespread and, in some cases, very dangerous for human health. The only effective treatment is the elimination of gluten from the diet throughout life. Nowadays, the food industries are very interested in cheap, easy-to-handle methods for detecting gluten in food, in order to provide their consumers with safe and high-quality food. Here, for the first time, the manufacture of controlled micropatterns of annealed gold nanoislands (AuNIs) on a single QCM crystal (QCM-color) and their biofunctionalization for the specific detection of traces of gliadin is reported. In addition, the modified quartz crystal with a TEM grid and 30 nm Au (Q-TEM grid crystal) is proposed as an acoustic sensitive biosensing platform for the rapid screening of the gliadin content in real food products. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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27 pages, 2476 KiB

Open AccessReview

Emerging Nano- and Micro-Technologies Used in the Treatment of Type-1 Diabetes

by Rosita Primavera, Bhavesh D Kevadiya, Ganesh Swaminathan, Rudilyn Joyce Wilson, Angelo De Pascale, Paolo Decuzzi and Avnesh S Thakor

Nanomaterials 2020, 10(4), 789; https://doi.org/10.3390/nano10040789 - 20 Apr 2020

Cited by 41 | Viewed by 7957

Abstract

Type-1 diabetes is characterized by high blood glucose levels due to a failure of insulin secretion from beta cells within pancreatic islets. Current treatment strategies consist of multiple, daily injections of insulin or transplantation of either the whole pancreas or isolated pancreatic islets. [...] Read more.

Type-1 diabetes is characterized by high blood glucose levels due to a failure of insulin secretion from beta cells within pancreatic islets. Current treatment strategies consist of multiple, daily injections of insulin or transplantation of either the whole pancreas or isolated pancreatic islets. While there are different forms of insulin with tunable pharmacokinetics (fast, intermediate, and long-acting), improper dosing continues to be a major limitation often leading to complications resulting from hyper- or hypo-glycemia. Glucose-responsive insulin delivery systems, consisting of a glucose sensor connected to an insulin infusion pump, have improved dosing but they still suffer from inaccurate feedback, biofouling and poor patient compliance. Islet transplantation is a promising strategy but requires multiple donors per patient and post-transplantation islet survival is impaired by inflammation and suboptimal revascularization. This review discusses how nano- and micro-technologies, as well as tissue engineering approaches, can overcome many of these challenges and help contribute to an artificial pancreas-like system. Full article

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13 pages, 4898 KiB

Open AccessArticle

Cellulose Nanocrystals Loaded with Thiamethoxam: Fabrication, Characterization, and Evaluation of Insecticidal Activity against Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

by Asem Elabasy, Ali Shoaib, Muhammad Waqas, Zuhua Shi and Mingxing Jiang

Nanomaterials 2020, 10(4), 788; https://doi.org/10.3390/nano10040788 - 20 Apr 2020

Cited by 25 | Viewed by 4669

Abstract

Using smart nanopesticide formulations based on nanomaterials can offer promising potential applications for decreasing pesticide residues and their effects on human health and the environment. In this study, a novel nanoformulation (NF) of thiamethoxam (TMX) was fabricated using the solvent evaporation method through [...] Read more.

Using smart nanopesticide formulations based on nanomaterials can offer promising potential applications for decreasing pesticide residues and their effects on human health and the environment. In this study, a novel nanoformulation (NF) of thiamethoxam (TMX) was fabricated using the solvent evaporation method through loading TMX on cellulose nanocrystals (CNCs) as the carrier. The synthesized TMX-CNCs was investigated through different techniques, such as Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and thermogravimetric analysis (TGA). The results revealed that the loading efficiency and entrapment efficiency were 18.7% and 83.7 ± 1.8% for TMX, respectively. The prepared nanoformulation (TMX-CNCs) had a width of 7–14 nm and a length of 85–214 nm with a zeta potential of −23.6 ± 0.3 mV. The drug release behavior study exhibited that the release of TMX from TMX-loaded CNCs was good and sustained. Furthermore, bioassay results showed that the insecticidal activity of TMX-CNCs against Phenacoccus solenopsis was significantly superior to that of the technical and commercial formulation, as indicated by the lower LC₅₀ value. The results indicate that the TMX nanoformulation has great potential for application in agriculture for pest control. Full article

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