Nanomaterials

17 pages, 4624 KiB

Open AccessArticle

Synthesis and Characterization of Hematite-Based Nanocomposites as Promising Catalysts for Indigo Carmine Oxidation

by Andrei Cristian Kuncser, Arpad Mihai Rostas, Rodica Zavoianu, Octavian Dumitru Pavel, Ioana Dorina Vlaicu, Mihaela Badea, Daniela Cristina Culita, Alina Tirsoaga and Rodica Olar

Nanomaterials 2022, 12(14), 2511; https://doi.org/10.3390/nano12142511 - 21 Jul 2022

Cited by 4 | Viewed by 2028

Abstract

The hematite-based nanomaterials are involved in several catalytic organic and inorganic processes, including water decontamination from organic pollutants. In order to develop such species, a series of bimetallic hematite-based nanocomposites were obtained by some goethite composites-controlled calcination. Their composition consists of various phases [...] Read more.

The hematite-based nanomaterials are involved in several catalytic organic and inorganic processes, including water decontamination from organic pollutants. In order to develop such species, a series of bimetallic hematite-based nanocomposites were obtained by some goethite composites-controlled calcination. Their composition consists of various phases such as α-FeOOH, α-Fe₂O₃ or γ-Fe₂O₃ combined with amorphous (Mn₂O₃, Co₃O₄, NiO, ZnO) or crystalline (CuO) oxides of the second transition ion from the structure. The component dimensions, either in the 10–30 or in the 100–200 nm range, together with the quasi-spherical or nanorod-like shapes, were provided by Mössbauer spectroscopy and powder X-ray diffraction as well as transmission electron microscopy data. The textural characterization showed a decrease in the specific area of the hematite-based nanocomposites compared with corresponding goethites, with the pore volume ranging between 0.219 and 0.278 cm³g⁻¹. The best catalytic activity concerning indigo carmine removal from water in hydrogen peroxide presence was exhibited by a copper-containing hematite-based nanocomposite sample that reached a dye removal extent of over 99%, which correlates with both the base/acid site ratio and pore size. Moreover, Cu-hbnc preserves its catalytic activity even after four recyclings, when it still reached a dye removal extent higher than 90%. Full article

(This article belongs to the Special Issue The Development of Nanomaterials in Adsorption, Separation and Purification)

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The chemical structure of indigo carmine. Full article ">Figure 2
Temperature dependence of the Fe-hbnc (a), Mn-hbnc (b), Co-hbnc (c), Ni-hbnc (d), Cu-hbnc (e), and Zn-hbnc (f) EPR signals. Full article ">Figure 3
Temperature dependence of the EPR signal peak-to-peak linewidth (ΔLWPP) for all species. Full article ">Figure 4
TEM results: CTEM, HRTEM, STEM, and EDS mappings for Fe-hbnc (a), Mn-hbnc (b), Co-hbnc (c), Ni-hbnc (d), Cu-hbnc (e), and Zn-hbnc (f). Full article ">Figure 5
N2 adsorption–desorption isotherms and pore size distribution (inset) of the samples: Fe−hbnc (a), Mn−hbnc (b), Co−hbnc (c), Ni−hbnc (d), Cu−hbnc (e), and Zn−hbnc (f). Full article ">Figure 6
Linear correlation of the DR % and the ratio base/acid sites in the catalyst samples ((A)—IC initial concentration 0.03 mM, 25 °C, 2 h, 150 rpm, 1 wt% catalyst; (B)—molar ratio H2O2/IC = 32.6, 25 °C, 2 h, 150 rpm, 1 wt% catalyst). Full article ">Figure 7
DR % during five reaction cycles on Fe-hbnc and Cu-hbnc (IC initial concentration 0.03 mM, molar ratio H2O2/IC = 32.6, 25 °C, 2 h, 150 rpm, 1 wt% catalyst). Full article ">

14 pages, 6931 KiB

Open AccessArticle

Fabrication of Durable Superhydrophobic Surface for Versatile Oil/Water Separation Based on HDTMS Modified PPy/ZnO

by Shumin Fan, Sujie Jiang, Zhenjie Wang, Pengchao Liang, Wenxiu Fan, Kelei Zhuo and Guangri Xu

Nanomaterials 2022, 12(14), 2510; https://doi.org/10.3390/nano12142510 - 21 Jul 2022

Cited by 6 | Viewed by 2254

Abstract

Superhydrophobic materials have been widely applied in rapid removal and collection of oils from oil/water mixtures for increasing damage to environment and human beings caused by oil-contaminated wastewater and oil spills. Herein, superhydrophobic materials were fabricated by a novel polypyrrole (PPy)/ZnO coating followed [...] Read more.

Superhydrophobic materials have been widely applied in rapid removal and collection of oils from oil/water mixtures for increasing damage to environment and human beings caused by oil-contaminated wastewater and oil spills. Herein, superhydrophobic materials were fabricated by a novel polypyrrole (PPy)/ZnO coating followed by hexadecyltrimethoxysilane (HDTMS) modification for versatile oil/water separation with high environmental and excellent reusability. The prepared superhydrophobic surfaces exhibited water contact angle (WCA) greater than 150° and SA less than 5°. The superhydrophobic fabric could be applied for separation of heavy oil or light oil/water mixtures and emulsions with the separation efficiencies above 98%. The coated fabric also realized highly efficient separation with harsh environmental solutions, such as acid, alkali, salt, and hot water. The superhydrophobic fabric still remained, even after 80 cycles of separation and 12 months of storage in air, proving excellent durability. These novel superhydrophobic materials have indicated great development potentials for oil/water separation in practical applications. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Environmental Remediation)

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15 pages, 5898 KiB

Open AccessArticle

Self-Supply Oxygen ROS Reactor via Fenton-like Reaction and Modulating Glutathione for Amplified Cancer Therapy Effect

by Huanli Zhang, Wei Ma, Zhiqiang Wang, Xiaodan Wu, Hui Zhang, Wen Fang, Rui Yan and Yingxue Jin

Nanomaterials 2022, 12(14), 2509; https://doi.org/10.3390/nano12142509 - 21 Jul 2022

Cited by 16 | Viewed by 2646

Abstract

Reactive oxygen species (ROS) are highly reactive oxidant molecules that can kill cancer cells through irreversible damage to biomacromolecules. ROS-mediated cancer therapies, such as chemodynamic (CDT) and photodynamic therapy (PDT), are often limited by the hypoxia tumor microenvironment (TME) with high glutathione (GSH) [...] Read more.

Reactive oxygen species (ROS) are highly reactive oxidant molecules that can kill cancer cells through irreversible damage to biomacromolecules. ROS-mediated cancer therapies, such as chemodynamic (CDT) and photodynamic therapy (PDT), are often limited by the hypoxia tumor microenvironment (TME) with high glutathione (GSH) level. This paper reported the preparation, characterization, in vitro and in vivo antitumor bioactivity of a meso-tetra(4-carboxyphenyl)porphine (TCPP)-based therapeutic nanoplatform (CMMFTP) to overcome the limitations of TME. Using Cu²⁺ as the central ion and TCPP as the ligand, the 2D metal-organic framework Cu-TCPP was synthesized by the solvothermal method, then CMMFTP was prepared by modifying MnO₂, folic acid (FA), triphenylphosphine (TPP), and poly (allylamine hydrochloride) (PAH) on the surface of Cu-TCPP MOFs. CMMFTP was designed as a self-oxygenating ROS nanoreactor based on the PDT process of TCPP MOFs and the CDT process by Cu(II) and MnO₂ components (mainly through Fenton-like reaction). The in vitro assay suggested CMMFTP caused a 96% lethality rate against Hela cells (MTT analysis) in specific response to TME stimulation. Moreover, the Cu(II) and MnO₂ in CMMFTP efficiently depleted the glutathione (80%) in tumor cells and consequently amplified ROS levels to improve CDT/PDT effects. The FA-induced tumor targeting and TPP-induced mitochondria targeting further enhanced the antitumor activity. Therefore, the nanoreactor based on dual targeting and self-oxygenation-enhanced ROS mechanism provided a new strategy for cancer therapy. Full article

(This article belongs to the Section Biology and Medicines)

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(A) Transmission electron microscopy (TEM) image of CMMFTP; (B) high-resolution transmission electron microscope (HR-TEM) image of CMMFTP (Inset: HR-TEM image of MnO2 nanocrystals); (C) X-ray diffraction (XRD) patterns of CMMFTP; (D) X-ray photoelectron spectroscopy (XPS) spectra of CMMFTP; (E) high-resolution X-ray photoelectron spectroscopy (HR-XPS) of C 1s; (F) HR-XPS of N 1s; (G) HR-XPS of Cu 2p; (H) HR-XPS of O 1s; (I) HR-XPS of Mn 2p; (J) Fourier transform infrared (FT-IR) spectra of TCPP, Cu-MOFs and CMMFTP; (K) UV-visible absorption spectra of TCPP, Cu-MOFs and CMMFTP; (L) Fluorescence emission spectrum of CMMFTP; (M) dark-field TEM image and corresponding elemental mappings images of CMMFTP. Full article ">Figure 2
(A) Detection of •OH generation capacity of various samples using MB; (B) •OH detection by ESR signals under different conditions; (C) detection of O2 production capacity of various samples using RDPP as a dissolved oxygen probe; (D) examine the ability of CMMFTP photosensitization to produce 1O2 using DPBF as singlet oxygen indicator probe; (E) standard curves of degradation rate and light time of DPBF; (F) fluorescence spectra and (G) fluorescence intensity histograms of 1O2 detected with the SOSG probe; (H) detection of GSH consumption by CMMFTP with DTNB probe. Full article ">Figure 3
(A) Time (100 µg/mL, 0–90 min) dependence and (B) concentration (30 min, 0–400 µg/mL) dependence images of cell uptake; (C) detection of mitochondrial targeting of CMMFTP with Mito-Tracker Green; (D) detection of the intracellular GSH depletion capacity of CMMFTP; (E) dark toxicity of CMMFTP in Hela cells; (F) dark toxicity of CMMFTP in normal cells; (G–I) comparison of the cytotoxicity of Cu-MOFs, Cu-MOF@MnO2, CMMFTP under different conditions. p < 0.05. Full article ">Figure 4
(A) Detection of intracellular ROS; (B) calcein-AM and PI co-staining of living and dead cells. Full article ">Figure 5
(A) Photographs of tumor-bearing mice in different experimental groups after 14 days of treatment; (B) images of tumors after different treatments; (C) changes in body weight of mice during treatment; (D) tumor volume and (E) tumor weight in different experimental groups after 14 days of treatment; (F) H&E staining images of heart, liver, spleen, lung, kidney, and tumors in different experimental groups after 14 days of treatment. Scale bar: 100 μm. ∗, p < 0.05; ∗∗, p < 0.01. Full article ">Scheme 1
The synthetic route and anti-tumor mechanism of a TME-responsive self-oxygenation-enhanced nanoreactor (CMMFTP) based on CDT/PDT synergy and GSH depletion strategy. Full article ">

9 pages, 2676 KiB

Open AccessArticle

AlGaN Quantum Disk Nanorods with Efficient UV-B Emission Grown on Si(111) Using Molecular Beam Epitaxy

by Dongqi Zhang, Tao Tao, Haiding Sun, Siqi Li, Hongfeng Jia, Huabin Yu, Pengfei Shao, Zhenhua Li, Yaozheng Wu, Zili Xie, Ke Wang, Shibing Long, Bin Liu, Rong Zhang and Youdou Zheng

Nanomaterials 2022, 12(14), 2508; https://doi.org/10.3390/nano12142508 - 21 Jul 2022

Viewed by 1544

Abstract

AlGaN nanorods have attracted increasing amounts of attention for use in ultraviolet (UV) optoelectronic devices. Here, self-assembled AlGaN nanorods with embedding quantum disks (Qdisks) were grown on Si(111) using plasma-assisted molecular beam epitaxy (PA-MBE). The morphology and quantum construction of the nanorods were [...] Read more.

AlGaN nanorods have attracted increasing amounts of attention for use in ultraviolet (UV) optoelectronic devices. Here, self-assembled AlGaN nanorods with embedding quantum disks (Qdisks) were grown on Si(111) using plasma-assisted molecular beam epitaxy (PA-MBE). The morphology and quantum construction of the nanorods were investigated and well-oriented and nearly defect-free nanorods were shown to have a high density of about 2 × 10¹⁰ cm⁻². By controlling the substrate temperature and Al/Ga ratio, the emission wavelengths of the nanorods could be adjusted from 276 nm to 330 nm. By optimizing the structures and growth parameters of the Qdisks, a high internal quantum efficiency (IQE) of the AlGaN Qdisk nanorods of up to 77% was obtained at 305 nm, which also exhibited a shift in the small emission wavelength peak with respect to the increasing temperatures during the PL measurements. Full article

(This article belongs to the Section Nanophotonics Materials and Devices)

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16 pages, 4733 KiB

Open AccessArticle

Thermally Evaporated Copper Iodide Hole-Transporter for Stable CdS/CdTe Thin-Film Solar Cells

by Thuraisamykurukkal Thivakarasarma, Adikari Arachchige Isuru Lakmal, Buddhika Senarath Dassanayake, Dhayalan Velauthapillai and Punniamoorthy Ravirajan

Nanomaterials 2022, 12(14), 2507; https://doi.org/10.3390/nano12142507 - 21 Jul 2022

Cited by 2 | Viewed by 2217

Abstract

This study focuses on fabricating efficient CdS/CdTe thin-film solar cells with thermally evaporated cuprous iodide (CuI) as hole-transporting material (HTM) by replacing Cu back contact in conventional CdS/CdTe solar cells to avoid Cu diffusion. In this study, a simple thermal evaporation method was [...] Read more.

This study focuses on fabricating efficient CdS/CdTe thin-film solar cells with thermally evaporated cuprous iodide (CuI) as hole-transporting material (HTM) by replacing Cu back contact in conventional CdS/CdTe solar cells to avoid Cu diffusion. In this study, a simple thermal evaporation method was used for the CuI deposition. The current-voltage characteristic of devices with CuI films of thickness 5 nm to 30 nm was examined under illuminations of 100 mW/cm² (1 sun) with an Air Mass (AM) of 1.5 filter. A CdS/CdTe solar cell device with thermally evaporated CuI/Au showed power conversion efficiency (PCE) of 6.92% with J_SC, V_OC, and FF of 21.98 mA/cm², 0.64 V, and 0.49 under optimized fabrication conditions. Moreover, stability studies show that fabricated CdS/CdTe thin-film solar cells with CuI hole-transporters have better stability than CdS/CdTe thin-film solar cells with Cu/Au back contacts. The significant increase in FF and, hence, PCE, and the stability of CdS/CdTe solar cells with CuI, reveals that Cu diffusion could be avoided by replacing Cu with CuI, which provides good band alignment with CdTe, as confirmed by XPS. Such an electronic band structure alignment allows smooth hole transport from CdTe to CuI, which acts as an electron reflector. Hence, CuI is a promising alternative stable hole-transporter for CdS/CdTe thin-film solar cells that increases the PCE and stability. Full article

(This article belongs to the Section Solar Energy and Solar Cells)

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9 pages, 2629 KiB

Open AccessArticle

Design and Simulation of Efficient SnS-Based Solar Cell Using Spiro-OMeTAD as Hole Transport Layer

by Pooja Tiwari, Maged F. Alotaibi, Yas Al-Hadeethi, Vaibhava Srivastava, Bassim Arkook, Sadanand, Pooja Lohia, Dilip Kumar Dwivedi, Ahmad Umar, Hassan Algadi and Sotirios Baskoutas

Nanomaterials 2022, 12(14), 2506; https://doi.org/10.3390/nano12142506 - 21 Jul 2022

Cited by 34 | Viewed by 2831

Abstract

In the present paper, the theoretical investigation of the device structure ITO/CeO₂/SnS/Spiro-OMeTAD/Mo of SnS-based solar cell has been performed. The aim of this work is to examine how the Spiro-OMeTAD HTL affects the performance of SnS-based heterostructure solar cell. Using SCAPS-1D [...] Read more.

In the present paper, the theoretical investigation of the device structure ITO/CeO₂/SnS/Spiro-OMeTAD/Mo of SnS-based solar cell has been performed. The aim of this work is to examine how the Spiro-OMeTAD HTL affects the performance of SnS-based heterostructure solar cell. Using SCAPS-1D simulation software, various parameters of SnS-based solar cell such as work function, series and shunt resistance and working temperature have been investigated. With the help of Spiro-OMeTAD, the suggested cell’s open-circuit voltage was increased to 344 mV. The use of Spiro-OMeTAD HTL in the SnS-based solar cell resulted in 14% efficiency increase, and the proposed heterojunction solar cell has 25.65% efficiency. The cell’s performance is determined by the carrier density and width of the CeO₂ ETL (electron transport layer), SnS absorber layer and Spiro-OMeTAD HTL (hole transport layer). These data reveal that the Spiro-OMeTAD solar cells could have been a good HTL (hole transport layer) in regards to producing SnS-based heterojunction solar cell with high efficiency and reduced cost. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Quantum Technology, Sensor and Health Therapy Applications)

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13 pages, 3550 KiB

Open AccessArticle

MoS₂-Decorated Graphene@porous Carbon Nanofiber Anodes via Centrifugal Spinning

by Elham Abdolrazzaghian, Jiadeng Zhu, Juran Kim and Meltem Yanilmaz

Nanomaterials 2022, 12(14), 2505; https://doi.org/10.3390/nano12142505 - 21 Jul 2022

Cited by 11 | Viewed by 2045

Abstract

Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries as green energy storage devices because of their similar working principles and the abundance of low-cost sodium resources. Nanostructured carbon materials are attracting great interest as high-performance anodes for SIBs. Herein, a simple and [...] Read more.

Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries as green energy storage devices because of their similar working principles and the abundance of low-cost sodium resources. Nanostructured carbon materials are attracting great interest as high-performance anodes for SIBs. Herein, a simple and fast technique to prepare carbon nanofibers (CNFs) is presented, and the effects of carbonization conditions on the morphology and electrochemical properties of CNF anodes in Li- and Na-ion batteries are investigated. Porous CNFs containing graphene were fabricated via centrifugal spinning, and MoS₂ were decorated on graphene-included porous CNFs via hydrothermal synthesis. The effect of MoS₂ on the morphology and the electrode performance was examined in detail. The results showed that the combination of centrifugal spinning, hydrothermal synthesis, and heat treatment is an efficient way to fabricate high-performance electrodes for rechargeable batteries. Furthermore, CNFs fabricated at a carbonization temperature of 800 °C delivered the highest capacity, and the addition of MoS₂ improved the reversible capacity up to 860 mAh/g and 455 mAh/g for Li- and Na-ion batteries, respectively. A specific capacity of over 380 mAh/g was observed even at a high current density of 1 A/g. Centrifugal spinning and hydrothermal synthesis allowed for the fabrication of high-performance electrodes for sodium ion batteries. Full article

(This article belongs to the Special Issue Fabrication and Characterization of Nanostructured Carbon Electrodes)

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SEM images of (A) PAN nanofibers and carbon nanofibers carbonized at (B) 700 °C (C) 800 °C, and (D) 900 °C. Full article ">Figure 2
XRD pattern (a) and RAMAN spectra (b) of carbon nanofibers carbonized at (A) 700 °C (B) 800 °C, and (C) 900 °C. Full article ">Figure 3
First-cycle charge/discharge curves of carbon nanofibers carbonized at (A,D) 700 °C, (B,E) 800 °C, and (C,F) 900 °C in Li-ion cells and Na-ion batteries and cycling performance in Li-ion batteries (G) and Na-ion batteries (H). Full article ">Figure 4
SEM images (A,B), of graphene@ porous carbon nanofiber and (C,D) MoS2-decorated graphene@ porous carbon nanofiber and TEM images of (E) graphene@ porous carbon nanofiber and (F) MoS2-decorated graphene@porous carbon nanofiber. Full article ">Figure 5
XRD pattern (a) and Raman spectra, D and G bands of carbon (b) of graphene@ porous carbon nanofiber (A), MoS2-decorated graphene@ porous carbon nanofiber (B), and TGA curve of MoS2-decorated on graphene@PCNFs (c). Full article ">Figure 6
First-cycle discharge/charge curves and cycling performance of graphene@ porous carbon nanofiber electrodes in Li-ion (A,C) and Na-ion batteries (B,D). Full article ">Figure 7
First-cycle discharge/charge curves and cycling performance of MoS2-decorated graphene@porous carbon nanofiber electrodes in Li-ion (A,C) and Na-ion batteries (B–E). Full article ">

14 pages, 3346 KiB

Open AccessArticle

Tailoring of AlAs/InAs/GaAs QDs Nanostructures via Capping Growth Rate

by Nazaret Ruiz, Daniel Fernandez, Esperanza Luna, Lazar Stanojević, Teresa Ben, Sara Flores, Verónica Braza, Alejandro Gallego-Carro, Guillermo Bárcena-González, Andres Yañez, José María Ulloa and David González

Nanomaterials 2022, 12(14), 2504; https://doi.org/10.3390/nano12142504 - 21 Jul 2022

Cited by 1 | Viewed by 1630

Abstract

The use of thin AlA capping layers (CLs) on InAs quantum dots (QDs) has recently received considerable attention due to improved photovoltaic performance in QD solar cells. However, there is little data on the structural changes that occur during capping and their relation [...] Read more.

The use of thin AlA capping layers (CLs) on InAs quantum dots (QDs) has recently received considerable attention due to improved photovoltaic performance in QD solar cells. However, there is little data on the structural changes that occur during capping and their relation to different growth conditions. In this work, we studied the effect of AlA capping growth rate (CGR) on the structural features of InAs QDs in terms of shape, size, density, and average content. As will be shown, there are notable differences in the characteristics of the QDs upon changing CGR. The Al distribution analysis in the CL around the QDs was revealed to be the key. On the one hand, for the lowest CGR, Al has a homogeneous distribution over the entire surface, but there is a large thickening of the CL on the sides of the QD. As a result, the QDs are lower, lenticular in shape, but richer in In. On the other hand, for the higher CGRs, Al accumulates preferentially around the QD but with a more uniform thickness, resulting in taller QDs, which progressively adopt a truncated pyramidal shape. Surprisingly, intermediate CGRs do not improve either of these behaviors, resulting in less enriched QDs. Full article

(This article belongs to the Special Issue Multijunction and Intermediated-Band Solar Cells for a Higher-Efficiency Solar Conversion: Nanomaterials and Structural Approaches)

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18 pages, 4224 KiB

Open AccessArticle

Evolution of the Electronic and Optical Properties of Meta-Stable Allotropic Forms of 2D Tellurium for Increasing Number of Layers

by Simone Grillo, Olivia Pulci and Ivan Marri

Nanomaterials 2022, 12(14), 2503; https://doi.org/10.3390/nano12142503 - 21 Jul 2022

Cited by 5 | Viewed by 2490

Abstract

In this work, ab initio Density Functional Theory calculations are performed to investigate the evolution of the electronic and optical properties of 2D Tellurium—called Tellurene—for three different allotropic forms (

α

-,

β

- and

γ

-phase), as a function of the number [...] Read more.

In this work, ab initio Density Functional Theory calculations are performed to investigate the evolution of the electronic and optical properties of 2D Tellurium—called Tellurene—for three different allotropic forms (

α

-,

β

- and

γ

-phase), as a function of the number of layers. We estimate the exciton binding energies and radii of the studied systems, using a 2D analytical model. Our results point out that these quantities are strongly dependent on the allotropic form, as well as on the number of layers. Remarkably, we show that the adopted method is suitable for reliably predicting, also in the case of Tellurene, the exciton binding energy, without the need of computationally demanding calculations, possibly suggesting interesting insights into the features of the system. Finally, we inspect the nature of the mechanisms ruling the interaction of neighbouring Tellurium atoms helical chains (characteristic of the bulk and

α

-phase crystal structures). We show that the interaction between helical chains is strong and cannot be explained by solely considering the van der Waals interaction. Full article

(This article belongs to the Special Issue Emerging Two-Dimensional Materials: Inspiring Nanotechnologies for Smart Energy Management)

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13 pages, 1749 KiB

Open AccessArticle

Isolation and Characterization of Cell Envelope Fragments Comprising Archaeal S-Layer Proteins

by Kevin Pfeifer, Eva-Kathrin Ehmoser, Simon K.-M. R. Rittmann, Christa Schleper, Dietmar Pum, Uwe B. Sleytr and Bernhard Schuster

Nanomaterials 2022, 12(14), 2502; https://doi.org/10.3390/nano12142502 - 21 Jul 2022

Cited by 2 | Viewed by 2002

Abstract

The outermost component of cell envelopes of most bacteria and almost all archaea comprise a protein lattice, which is termed Surface (S-)layer. The S-layer lattice constitutes a highly porous structure with regularly arranged pores in the nm-range. Some archaea thrive in extreme milieus, [...] Read more.

The outermost component of cell envelopes of most bacteria and almost all archaea comprise a protein lattice, which is termed Surface (S-)layer. The S-layer lattice constitutes a highly porous structure with regularly arranged pores in the nm-range. Some archaea thrive in extreme milieus, thus producing highly stable S-layer protein lattices that aid in protecting the organisms. In the present study, fragments of the cell envelope from the hyperthermophilic acidophilic archaeon Saccharolobus solfataricus P2 (SSO) have been isolated by two different methods and characterized. The organization of the fragments and the molecular sieving properties have been elucidated by transmission electron microscopy and by determining the retention efficiency of proteins varying in size, respectively. The porosity of the archaeal S-layer fragments was determined to be 45%. S-layer fragments of SSO showed a retention efficiency of up to 100% for proteins having a molecular mass of ≥ 66 kDa. Moreover, the extraction costs for SSO fragments have been reduced by more than 80% compared to conventional methods, which makes the use of these archaeal S-layer material economically attractive. Full article

(This article belongs to the Section Nanocomposite Materials)

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(A) Saccharolobus solfataricus P2 (SSO) ghost prepared using the extraction with DNase I (DEG). (B,C) SSO ghosts prepared using the extraction method with sonication (SEG). Scale Bars: A = 100 nm; B = 500 nm; C = 250 nm. Full article ">Figure 2
SDS-PAGE (4–20% Bis-Tris, MES) S1–S3: 20 µL of Saccharolobus solfataricus P2 (SSO) sacculi using the extraction method with sonication (SEG). D1–D3: 20 µL of SSO sacculi using the established extraction method with DNase I (DEG). The first lane corresponds to molecular mass standard with ladder units in kDa. Full article ">Figure 3
(A) Transmission electron micrograph of Saccharolobus solfataricus P2 (SSO) fragments after sonication. Bar, 1000 nm; (B) computer image reconstruction (2D projection) of the p3-ordered hexagonal S-layer lattice from SSO. Shown are a unit cell and the corresponding three-fold axis of rotation (symmetry operators) in blue. The protein is light, the pores are dark. In addition, a possible configuration of proteins belonging to a unit cell is shown by strokes drawn by hand in orange. Bar, 20 nm; (C) scanning electron micrograph of SSO fragments deposited on microfilter 1 (100,000× magnification). Bar, 500 nm. Full article ">Figure 4
(A) Average efficiency of Saccharolobus solfataricus P2 fragments deposited on microfilter 1 (SSOMF1) across all experiments (n ≥ 6); (B) retention efficiency of SSOMF1 where Orange = filtration sequence largest to smallest protein (n ≥ 3) and Blue = filtration sequence smallest to largest protein (n ≥ 3); Legend for A and B: ▬ = myoglobin (17 kDa); ■ = carbonic anhydrase (31 kDa); ♦ = horseradish peroxidase (44 kDa); ▲ = bovine serum albumin (66 kDa); x = amyloglucosidase (97 kDa) and ● = γ-globulin (125 kDa). Full article ">Figure 5
Retention efficiency of Saccharolobus solfataricus P2 fragments deposited on microfilter 2 (SSOMF2) (orange); B. stearothermophilus pV72 (yellow) and C. thermohydrosulfuricum L111-69 (gray). The proteins with increasing molecular mass are myoglobin (17 kDa), carbonic anhydrase (31 kDa), ovalbumin (43 kDa; for bacterial SLP material), horseradish peroxidase (44 kDa; for SSOMF2), bovine serum albumin (66 kDa), and amyloglucosidase (97 kDa) (n ≥ 4). Data for the retention curve of B. stearothermophilus pV72 and C. thermohydrosulfuricum L111-69 are taken from Ref. [<a href="#B25-nanomaterials-12-02502" class="html-bibr">25</a>]. Full article ">

35 pages, 4514 KiB

Open AccessEditor’s ChoiceReview

Semiconductor Quantum Dots as Target Analytes: Properties, Surface Chemistry and Detection

by Jesús Sanmartín-Matalobos, Pilar Bermejo-Barrera, Manuel Aboal-Somoza, Matilde Fondo, Ana M. García-Deibe, Julio Corredoira-Vázquez and Yeneva Alves-Iglesias

Nanomaterials 2022, 12(14), 2501; https://doi.org/10.3390/nano12142501 - 21 Jul 2022

Cited by 19 | Viewed by 4622

Abstract

Since the discovery of Quantum Dots (QDs) by Alexey I. Ekimov in 1981, the interest of researchers in that particular type of nanomaterials (NMs) with unique optical and electrical properties has been increasing year by year. Thus, since 2009, the number of scientific [...] Read more.

Since the discovery of Quantum Dots (QDs) by Alexey I. Ekimov in 1981, the interest of researchers in that particular type of nanomaterials (NMs) with unique optical and electrical properties has been increasing year by year. Thus, since 2009, the number of scientific articles published on this topic has not been less than a thousand a year. The increasing use of QDs due to their biomedical, pharmaceutical, biological, photovoltaics or computing applications, as well as many other high-tech uses such as for displays and solid-state lighting (SSL), has given rise to a considerable number of studies about its potential toxicity. However, there are a really low number of reported studies on the detection and quantification of QDs, and these include ICP–MS and electrochemical analysis, which are the most common quantification techniques employed for this purpose. The knowledge of chemical phenomena occurring on the surface of QDs is crucial for understanding the interactions of QDs with species dissolved in the dispersion medium, while it paves the way for a widespread use of chemosensors to facilitate its detection. Keeping in mind both human health and environmental risks of QDs as well as the scarcity of analytical techniques and methodological approaches for their detection, the adaptation of existing techniques and methods used with other NMs appears necessary. In order to provide a multidisciplinary perspective on QD detection, this review focused on three interrelated key aspects of QDs: properties, surface chemistry and detection. Full article

(This article belongs to the Special Issue Nanoparticle Analysis, Toxicity and Environmental Impact)

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3 pages, 204 KiB

Open AccessEditorial

Functional Biodegradable Nanocomposites

by Agueda Sonseca, Coro Echeverría and Daniel López

Nanomaterials 2022, 12(14), 2500; https://doi.org/10.3390/nano12142500 - 21 Jul 2022

Viewed by 1233

Abstract

Over 367 million tons of plastics are produced annually worldwide, and the growth of plastic pollution has become a global concern [...] Full article

(This article belongs to the Special Issue Functional Biodegradable Nanocomposites)

11 pages, 1970 KiB

Open AccessArticle

A Self-Assembly of Single Layer of Co Nanorods to Reveal the Magnetostatic Interaction Mechanism

by Hongyu Du, Min Zhang, Ke Yang, Baohe Li and Zhenhui Ma

Nanomaterials 2022, 12(14), 2499; https://doi.org/10.3390/nano12142499 - 21 Jul 2022

Cited by 2 | Viewed by 1459

Abstract

In this work, we report a self-assembly method to fabricate a single layer of Co nanorods to study their magnetostatic interaction behavior. The Co nanorods with cambered and flat tips were synthesized by using a solvothermal route and an alcohol–thermal method, respectively. Both [...] Read more.

In this work, we report a self-assembly method to fabricate a single layer of Co nanorods to study their magnetostatic interaction behavior. The Co nanorods with cambered and flat tips were synthesized by using a solvothermal route and an alcohol–thermal method, respectively. Both of them represent hard magnetic features. Co nanorods with cambered tips have an average diameter of 10 nm and length of 100 nm with coercivity of 6.4 kOe, and flat-tip nanorods with a 30 nm diameter and 100 nm length exhibit a coercivity of 4.9 kOe. They are further assembled on the surface of water in assistance of surfactants. The results demonstrate that the assembly type is dependent on the magnetic induction lines direction. For Co nanorods with flat tips, most of magnetic induction lines are parallel to the length direction, leading to an assembly that is tip to tip. For Co nanorods with cambered tips, they are prone to holding together side by side for their random magnetic induction lines. Under an applied field, the Co nanorods with flat tips can be further aligned into a single layer of Co nanorods. Our work gives a possible mechanism for the magnetic interaction of Co nanorods and provides a method to study their magnetic behavior. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Electrochemical Energy Conversion and Storage)

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The Co nanorods with cambered tips by solvothermal route: (A) XRD pattern compared with standard hcp-Co (JCPDS No. 01-1278); (B,C) TEM images with different magnification; (D) HRTEM image. Full article ">Figure 2
(A–C) The TEM images of self-assembly Co nanorods with cambered tips by solvothermal route; (D) Magnetic hysteresis loop of Co nanorods at room temperature. Full article ">Figure 3
The Co nanorods with flat tips by alcohol–thermal method. (A) XRD pattern compared with standard hcp-Co (JCPDS No. 01-1278); (B,C) TEM images of Co nanorods with 100 r/min stirring rate; (D) TEM image of Co nanorods with 50 r/min stirring rate. Full article ">Figure 4
Magnetic hysteresis loop of Co nanorods with flat tips at room temperature. Full article ">Figure 5
(A,B) The TEM images of self-assembly Co nanorods with flat tips, without applied field; (C) XRD pattern of aligned Co nanorods under magnetic field compared with standard hcp-Co (JCPDS No. 01-1278); (D) TEM image of aligned Co nanorods under magnetic field. Full article ">Figure 6
The scheme of magnetostatic interaction mechanism: (A) Co nanorods with flat tips and (B) Co nanorods with cambered tips. Full article ">

8 pages, 2482 KiB

Open AccessArticle

Boosting the Humidity Performances of Na_0.5Bi_xTiO₃ by Tuning Bi Content

by Xiaoqi Xuan, Li Li, Tiantian Li, Jingsong Wang, Yi Yu and Chunchang Wang

Nanomaterials 2022, 12(14), 2498; https://doi.org/10.3390/nano12142498 - 21 Jul 2022

Viewed by 1285

Abstract

In the field of humidity sensors, a major challenge is how to improve the sensing performance of existing materials. Based on our previous work on Na_0.5Bi_0.5TiO₃, a facile strategy of tuning the Bi content in the material [...] Read more.

In the field of humidity sensors, a major challenge is how to improve the sensing performance of existing materials. Based on our previous work on Na_0.5Bi_0.5TiO₃, a facile strategy of tuning the Bi content in the material was proposed to improve its sensing performance. Na_0.5Bi_xTiO₃ (x = 0.3, 0.35, 0.4, 0.45) nanocomposites were synthesized by a hydrothermal method. Humidity sensing properties of these nanocomposites were investigated in the relative humidity range of 11% to 95%. Our results show that, compared to the sensor based on nominally pure sample (Na_0.5Bi_0.5TiO₃), the sensor based on Na_0.5Bi_0.35TiO₃ exhibits boosted sensing performance of excellent linear humidity response in the humidity range of 11–75% relative humidity, lower hysteresis value, and faster response/recovery time. The improvement of the sensing performance was argued to be the reason that the proper reduction in Bi content leads to a minimum value of oxygen-vacancy concentrations, thereby weakening the chemical adsorption but enhancing the physical adsorption. These results indicate that the proper underdose of the Bi content in Na_0.5Bi_0.5TiO₃ can greatly boost the sensing performance. Full article

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21 pages, 5922 KiB

Open AccessArticle

All-Solution Processed Single-Layer WOLEDs Using [Pt(salicylidenes)] as Guests in a PFO Matrix

by José Carlos Germino, Luís Gustavo Teixeira Alves Duarte, Rodrigo Araújo Mendes, Marcelo Meira Faleiros, Andreia de Morais, Jilian Nei de Freitas, Luiz Pereira and Teresa Dib Zambon Atvars

Nanomaterials 2022, 12(14), 2497; https://doi.org/10.3390/nano12142497 - 20 Jul 2022

Cited by 3 | Viewed by 2142

Abstract

Herein, we report the synthesis and characterization of two Pt(II) coordination compounds, the new platinum(II)[N,N′-bis(salicylidene)-3,4-diaminobenzophenone)] ([Pt(sal-3,4-ben)]) and the already well-known platinum(II)[N,N′-bis(salicylidene)-o-phenylenediamine] ([Pt(salophen)]), along with their application as guests in a poly [9,9-dioctylfluorenyl-2,7-diyl] (PFO) conjugated polymer [...] Read more.

Herein, we report the synthesis and characterization of two Pt(II) coordination compounds, the new platinum(II)[N,N′-bis(salicylidene)-3,4-diaminobenzophenone)] ([Pt(sal-3,4-ben)]) and the already well-known platinum(II)[N,N′-bis(salicylidene)-o-phenylenediamine] ([Pt(salophen)]), along with their application as guests in a poly [9,9-dioctylfluorenyl-2,7-diyl] (PFO) conjugated polymer in all-solution processed single-layer white organic light-emitting diodes. Completely different performances were achieved: 2.2% and 15.3% of external quantum efficiencies; 2.8 cd A⁻¹ and 12.1 cd A⁻¹ of current efficiencies; and 3103 cd m⁻² and 6224 cd m⁻² of luminance for the [Pt(salophen)] and [Pt(sal-3,4-ben)] complexes, respectively. The Commission Internationale de l’Eclairage (CIE 1931) chromaticity color coordinates are (0.33, 0.33) for both 0.1% mol/mol Pt(II):PFO composites at between approximately 3.2 and 8 V. The optoelectronic properties of doped and neat PFO films have been investigated, using steady-state and time-resolved photoluminescence. Theoretical calculations at the level of relativistic density functional theory explained these results, based on the presence of the Pt(II) central ion’s phosphorescence emission, considering spin-orbit coupling relationships. The overall results are explained, taking into account the active layer morphological properties, along with the device’s electric balance and the emitter’s efficiencies, according to deep-trap space-charge models. Considering the very simple structure of the device and the ease of synthesis of such compounds, the developed framework can offer a good trade-off for solution-deposited white organic light-emitting diodes (WOLEDs), with further applications in the field of lighting and signage. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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3 pages, 212 KiB

Open AccessEditorial

Special Issue “Advanced Nanomaterials for Bioimaging”

by Gang Ho Lee

Nanomaterials 2022, 12(14), 2496; https://doi.org/10.3390/nano12142496 - 20 Jul 2022

Cited by 1 | Viewed by 1250

Abstract

Bioimaging currently plays a critical role in medical diagnosis [...] Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Bioimaging)

25 pages, 6988 KiB

Open AccessReview

Recent Progress in Flexible Pressure Sensor Arrays

by Yanhao Duan, Shixue He, Jian Wu, Benlong Su and Youshan Wang

Nanomaterials 2022, 12(14), 2495; https://doi.org/10.3390/nano12142495 - 20 Jul 2022

Cited by 38 | Viewed by 7368

Abstract

Flexible pressure sensors that can maintain their pressure sensing ability with arbitrary deformation play an essential role in a wide range of applications, such as aerospace, prosthetics, robotics, healthcare, human–machine interfaces, and electronic skin. Flexible pressure sensors with diverse conversion principles and structural [...] Read more.

Flexible pressure sensors that can maintain their pressure sensing ability with arbitrary deformation play an essential role in a wide range of applications, such as aerospace, prosthetics, robotics, healthcare, human–machine interfaces, and electronic skin. Flexible pressure sensors with diverse conversion principles and structural designs have been extensively studied. At present, with the development of 5G and the Internet of Things, there is a huge demand for flexible pressure sensor arrays with high resolution and sensitivity. Herein, we present a brief description of the present flexible pressure sensor arrays with different transduction mechanisms from design to fabrication. Next, we discuss the latest progress of flexible pressure sensor arrays for applications in human–machine interfaces, healthcare, and aerospace. These arrays can monitor the spatial pressure and map the trajectory with high resolution and rapid response beyond human perception. Finally, the outlook of the future and the existing problems of pressure sensor arrays are presented. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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14 pages, 3456 KiB

Open AccessEditor’s ChoiceArticle

Tunable Spin and Orbital Edelstein Effect at (111) LaAlO₃/SrTiO₃ Interface

by Mattia Trama, Vittorio Cataudella, Carmine Antonio Perroni, Francesco Romeo and Roberta Citro

Nanomaterials 2022, 12(14), 2494; https://doi.org/10.3390/nano12142494 - 20 Jul 2022

Cited by 8 | Viewed by 2046

Abstract

Converting charge current into spin current is one of the main mechanisms exploited in spintronics. One prominent example is the Edelstein effect, namely, the generation of a magnetization in response to an external electric field, which can be realized in systems with lack [...] Read more.

Converting charge current into spin current is one of the main mechanisms exploited in spintronics. One prominent example is the Edelstein effect, namely, the generation of a magnetization in response to an external electric field, which can be realized in systems with lack of inversion symmetry. If a system has electrons with an orbital angular momentum character, an orbital magnetization can be generated by the applied electric field, giving rise to the so-called orbital Edelstein effect. Oxide heterostructures are the ideal platform for these effects due to the strong spin–orbit coupling and the lack of inversion symmetries. Beyond a gate-tunable spin Edelstein effect, we predict an orbital Edelstein effect an order of magnitude larger then the spin one at the (111) LaAlO

_{3}

/SrTiO

_{3}

interface for very low and high fillings. We model the material as a bilayer of

t_{2 g}

orbitals using a tight-binding approach, whereas transport properties are obtained in the Boltzmann approach. We give an effective model at low filling, which explains the non-trivial behaviour of the Edelstein response, showing that the hybridization between the electronic bands crucially impacts the Edelstein susceptibility. Full article

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Figure 1
(a) Ti atoms in STO lattice, whose lattice constant is <math display="inline"><semantics> <mrow> <msub> <mi>a</mi> <mn>0</mn> </msub> <mo>=</mo> <mn>0.3905</mn> </mrow> </semantics></math> nm. The blue and yellow dots represent atoms belonging to two non-equivalent planes. (b) Projection of the two non-equivalent planes of Ti over the (111) plane with our choice of primitive vectors <math display="inline"><semantics> <msub> <mover accent="true"> <mi>R</mi> <mo stretchy="false">→</mo> </mover> <mn>1</mn> </msub> </semantics></math> and <math display="inline"><semantics> <msub> <mover accent="true"> <mi>R</mi> <mo stretchy="false">→</mo> </mover> <mn>2</mn> </msub> </semantics></math> and <math display="inline"><semantics> <mrow> <mover accent="true"> <mi>a</mi> <mo>˜</mo> </mover> <mo>=</mo> <msqrt> <mrow> <mn>2</mn> <mo>/</mo> <mn>3</mn> </mrow> </msqrt> <msub> <mi>a</mi> <mn>0</mn> </msub> </mrow> </semantics></math>. (c) Band structure along two different directions in the Brillouin zone. The purple benchmark line corresponds to a Lifshitz transition (see <a href="#app3-nanomaterials-12-02494" class="html-app">Appendix C</a>). Full article ">Figure 2
In-plane spin (upper panel) and orbital angular momentum (lower panel) textures for the three doublets with the chemical potential fixed to the value corresponding to the benchmark line 3 in <a href="#nanomaterials-12-02494-f001" class="html-fig">Figure 1</a>. The red and green arrows represent the mean value of the in-plane component of the operator for the external band, and the blue and purple refer to the internal component. The mean value of the generic operator O is evaluated as <math display="inline"><semantics> <mrow> <mrow> <mo>〈</mo> <mi>O</mi> <mo>〉</mo> </mrow> <mo>=</mo> <msqrt> <mrow> <msup> <mrow> <mo>〈</mo> <msub> <mi>O</mi> <mrow> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mn>10</mn> </mrow> </msub> <mo>〉</mo> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mo>〈</mo> <msub> <mi>O</mi> <mrow> <mover> <mn>11</mn> <mo>¯</mo> </mover> <mn>2</mn> </mrow> </msub> <mo>〉</mo> </mrow> <mn>2</mn> </msup> </mrow> </msqrt> </mrow> </semantics></math>. Full article ">Figure 3
Spin (a) and orbital (b) Edelstein coefficient as a function of the chemical potential. The different colours correspond to the contribution of a specific Kramers doublet. Full article ">Figure 4
Spin (upper panel) and orbital (lower panel) Edelstein susceptibility projected over the L, M, and U states. The chemical potential <math display="inline"><semantics> <mi>μ</mi> </semantics></math> is fixed at values 1, 2, and 3, referring to <a href="#nanomaterials-12-02494-f001" class="html-fig">Figure 1</a>. Full article ">Figure A1
In-plane spin (upper panel) and orbital angular momentum (lower panel) textures for the first and the second doublet with the chemical potential fixed to the value corresponding to the benchmark lines 1 and 2 in <a href="#nanomaterials-12-02494-f001" class="html-fig">Figure 1</a>. The red and green arrows represent the mean value of the in-plane component of the operator for the external band, and the blue and pink refer to the internal component. The mean value of the generic operator O is evaluated as <math display="inline"><semantics> <mrow> <mrow> <mo>〈</mo> <mi>O</mi> <mo>〉</mo> </mrow> <mo>=</mo> <msqrt> <mrow> <msup> <mrow> <mo>〈</mo> <msub> <mi>O</mi> <mrow> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mn>10</mn> </mrow> </msub> <mo>〉</mo> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup> <mrow> <mo>〈</mo> <msub> <mi>O</mi> <mrow> <mover> <mn>11</mn> <mo>¯</mo> </mover> <mn>2</mn> </mrow> </msub> <mo>〉</mo> </mrow> <mn>2</mn> </msup> </mrow> </msqrt> </mrow> </semantics></math>. Full article ">Figure A2
Graph of <math display="inline"><semantics> <mrow> <mn>1</mn> <mo>/</mo> <mi>τ</mi> </mrow> </semantics></math> as a function of the chemical potential for a benchmark direction in the Brillouin zone. The dashed line corresponds to the inverse of the scattering time used in the main text. The purple vertical line corresponds to the energy at which a Lifshitz transition occurs for first band (see <a href="#nanomaterials-12-02494-f0A3" class="html-fig">Figure A3</a>). Full article ">Figure A3
Spin (a) and orbital (b) Edelstein coefficient as a function of the chemical potential using a scattering time model with a point-like impurity. The different colours correspond to the contribution of a specific Kramers doublet, whereas the dashed line corresponds to the total Edelstein response for a constant <math display="inline"><semantics> <mi>τ</mi> </semantics></math>. The inset in panel (a) corresponds to the detail of the Fermi energy contour for the purple chemical potential line. Full article ">

16 pages, 10763 KiB

Open AccessArticle

Formation of Nano- and Micro-Scale Surface Features Induced by Long-Range Femtosecond Filament Laser Ablation

by Joerg Schille, Jose R. Chirinos, Xianglei Mao, Lutz Schneider, Matthias Horn, Udo Loeschner and Vassilia Zorba

Nanomaterials 2022, 12(14), 2493; https://doi.org/10.3390/nano12142493 - 20 Jul 2022

Cited by 2 | Viewed by 2223

Abstract

In this work, we study the characteristics of femtosecond-filament-laser–matter interactions and laser-induced periodic surface structures (LIPSS) at a beam-propagation distance up to 55 m. The quantification of the periodicity of filament-induced self-organized surface structures was accomplished by SEM and AFM measurements combined with [...] Read more.

In this work, we study the characteristics of femtosecond-filament-laser–matter interactions and laser-induced periodic surface structures (LIPSS) at a beam-propagation distance up to 55 m. The quantification of the periodicity of filament-induced self-organized surface structures was accomplished by SEM and AFM measurements combined with the use of discrete two-dimensional fast Fourier transform (2D-FFT) analysis, at different filament propagation distances. The results show that the size of the nano-scale surface features increased with ongoing laser filament processing and, further, periodic ripples started to form in the ablation-spot center after irradiation with five spatially overlapping pulses. The effective number of irradiating filament pulses per spot area affected the developing surface texture, with the period of the low spatial frequency LIPSS reducing notably at a high pulse number. The high regularity of the filament-induced ripples was verified by the demonstration of the angle-of-incidence-dependent diffraction of sunlight. This work underlines the potential of long-range femtosecond filamentation for energy delivery at remote distances, with suppressed diffraction and long depth focus, which can be used in biomimetic laser surface engineering and remote-sensing applications. Full article

(This article belongs to the Special Issue Dynamics and Processes at Laser-Irradiated Surfaces—A Themed Issue in Honor of the 70th Birthday of Professor Jürgen Reif)

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10 pages, 454 KiB

Open AccessArticle

Band Structure Near the Dirac Point in HgTe Quantum Wells with Critical Thickness

by Alexey Shuvaev, Vlad Dziom, Jan Gospodarič, Elena G. Novik, Alena A. Dobretsova, Nikolay N. Mikhailov, Ze Don Kvon and Andrei Pimenov

Nanomaterials 2022, 12(14), 2492; https://doi.org/10.3390/nano12142492 - 20 Jul 2022

Cited by 7 | Viewed by 1722

Abstract

Mercury telluride (HgTe) thin films with a critical thickness of 6.5 nm are predicted to possess a gapless Dirac-like band structure. We report a comprehensive study on gated and optically doped samples by magnetooptical spectroscopy in the THz range. The quasi-classical analysis of [...] Read more.

Mercury telluride (HgTe) thin films with a critical thickness of 6.5 nm are predicted to possess a gapless Dirac-like band structure. We report a comprehensive study on gated and optically doped samples by magnetooptical spectroscopy in the THz range. The quasi-classical analysis of the cyclotron resonance allowed the mapping of the band dispersion of Dirac charge carriers in a broad range of electron and hole doping. A smooth transition through the charge neutrality point between Dirac holes and electrons was observed. An additional peak coming from a second type of holes with an almost density-independent mass of around

0.04 m_{0}

was detected in the hole-doping range and attributed to an asymmetric spin splitting of the Dirac cone. Spectroscopic evidence for disorder-induced band energy fluctuations could not be detected in present cyclotron resonance experiments. Full article

(This article belongs to the Special Issue Semiconductor Quantum Wells and Nanostructures)

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18 pages, 4488 KiB

Open AccessArticle

Adsorptive Removal of Naproxen from Water Using Polyhedral Oligomeric Silesquioxane (POSS) Covalent Organic Frameworks (COFs)

by Suleiman Bala, Che Azurahanim Che Abdullah, Mohamed Ibrahim Mohamed Tahir and Mohd Basyaruddin Abdul Rahman

Nanomaterials 2022, 12(14), 2491; https://doi.org/10.3390/nano12142491 - 20 Jul 2022

Cited by 12 | Viewed by 2355

Abstract

Covalent organic frameworks are porous crystalline compounds made up of organic material bonded together by strong reversible covalent bonds (these are novel types of materials which have the processability of extended or repeated structures with high performance, like those of thermosets and thermoplastics [...] Read more.

Covalent organic frameworks are porous crystalline compounds made up of organic material bonded together by strong reversible covalent bonds (these are novel types of materials which have the processability of extended or repeated structures with high performance, like those of thermosets and thermoplastics that produce high surface coverage). These have a long-term effect on an arrangement’s geometry and permeability. These compounds are entirely made up of light elements like H, B, C, N, O and Si. Pharmaceuticals and personal care products (PPCPs) have emerged as a new threatened species. A hazardous substance known as an “emerging toxin,” such as naproxen, is one that has been established or is generated in sufficient amounts in an environment, creating permanent damage to organisms. COF-S7, OAPS and 2-methylanthraquionone(2-MeAQ), and COF-S12, OAPS and terephthalaldehyde (TPA) were effectively synthesized by condensation (solvothermal) via a Schiff base reaction (R₁R₂C=NR′), with a molar ratio of 1:8 for OAPS to linker (L1 and L2), at a temperature of 125 °C and 100 °C for COF-S7 and COF-S12, respectively. The compounds obtained were assessed using several spectroscopy techniques, which revealed azomethine C=N bonds, aromatic carbon environments via solid ¹³C and ²⁹Si NMR, the morphological structure and porosity, and the thermostability of these materials. The remedied effluent was investigated, and a substantial execution was noted in the removal ability of the naproxen over synthesized materials, such as 70% and 86% at a contact time of 210 min and 270 min, respectively, at a constant dose of 0.05 g and pH 7. The maximum adsorption abilities of the substances were found to be 35 mg/g and 42 mg/g. The pH result implies that there is stable exclusion with a rise in pH to 9. At pH 9, the drop significance was attained for COF-S7 with the exception of COF-S12, which was detected at pH 11, due to the negative Foster charge, consequent to the repulsion among the synthesized COFs and naproxen solution. From the isotherms acquired (Langmuir and Freundlich), the substances displayed a higher value (close to 1) of correlation coefficient (R²), which showed that the substances fit into the Freundlich isotherm (heterogenous process), and the value of heterogeneity process (n) achieved (less than 1) specifies that the adsorption is a chemical process. Analysis of the as-prepared composites revealed remarkable reusability in the elimination of naproxen by adsorption. Due to its convenience of synthesis, significant adsorption effectiveness, and remarkable reusability, the as-synthesized COFs are expected to be able to be used as potential adsorbents for eliminating AIDs from water. Full article

(This article belongs to the Topic Synthesis, Characterization and Performance of Materials for a Sustainable Future)

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21 pages, 3573 KiB

Open AccessFeature PaperArticle

Preliminary Evaluation of Iron Oxide Nanoparticles Radiolabeled with ⁶⁸Ga and ¹⁷⁷Lu as Potential Theranostic Agents

by Evangelia-Alexandra Salvanou, Argiris Kolokithas-Ntoukas, Christos Liolios, Stavros Xanthopoulos, Maria Paravatou-Petsotas, Charalampos Tsoukalas, Konstantinos Avgoustakis and Penelope Bouziotis

Nanomaterials 2022, 12(14), 2490; https://doi.org/10.3390/nano12142490 - 20 Jul 2022

Cited by 12 | Viewed by 2310

Abstract

Theranostic radioisotope pairs such as Gallium-68 (⁶⁸Ga) for Positron Emission Tomography (PET) and Lutetium-177 (¹⁷⁷Lu) for radioisotopic therapy, in conjunction with nanoparticles (NPs), are an emerging field in the treatment of cancer. The present work aims to demonstrate the [...] Read more.

Theranostic radioisotope pairs such as Gallium-68 (⁶⁸Ga) for Positron Emission Tomography (PET) and Lutetium-177 (¹⁷⁷Lu) for radioisotopic therapy, in conjunction with nanoparticles (NPs), are an emerging field in the treatment of cancer. The present work aims to demonstrate the ability of condensed colloidal nanocrystal clusters (co-CNCs) comprised of iron oxide nanoparticles, coated with alginic acid (MA) and stabilized by a layer of polyethylene glycol (MAPEG) to be directly radiolabeled with ⁶⁸Ga and its therapeutic analog ¹⁷⁷Lu. ⁶⁸Ga/¹⁷⁷Lu- MA and MAPEG were investigated for their in vitro stability. The biocompatibility of the non-radiolabeled nanoparticles, as well as the cytotoxicity of MA, MAPEG, and [¹⁷⁷Lu]Lu-MAPEG were assessed on 4T1 cells. Finally, the ex vivo biodistribution of the ⁶⁸Ga-labeled NPs as well as [¹⁷⁷Lu]Lu-MAPEG was investigated in normal mice. Radiolabeling with both radioisotopes took place via a simple and direct labelling method without further purification. Hemocompatibility was verified for both NPs, while MTT studies demonstrated the non-cytotoxic profile of the nanocarriers and the dose-dependent toxicity for [¹⁷⁷Lu]Lu-MAPEG. The radiolabeled nanoparticles mainly accumulated in RES organs. Based on our preliminary results, we conclude that MAPEG could be further investigated as a theranostic agent for PET diagnosis and therapy of cancer. Full article

(This article belongs to the Special Issue Nanoparticles in Diagnostic and Therapeutic Applications)

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14 pages, 6542 KiB

Open AccessArticle

Mechanical Load-Induced Atomic-Scale Deformation Evolution and Mechanism of SiC Polytypes Using Molecular Dynamics Simulation

by Haoxiang Wang, Shang Gao, Renke Kang, Xiaoguang Guo and Honggang Li

Nanomaterials 2022, 12(14), 2489; https://doi.org/10.3390/nano12142489 - 20 Jul 2022

Cited by 22 | Viewed by 2548

Abstract

Silicon carbide (SiC) is a promising semiconductor material for making high-performance power electronics with higher withstand voltage and lower loss. The development of cost-effective machining technology for fabricating SiC wafers requires a complete understanding of the deformation and removal mechanism. In this study, [...] Read more.

Silicon carbide (SiC) is a promising semiconductor material for making high-performance power electronics with higher withstand voltage and lower loss. The development of cost-effective machining technology for fabricating SiC wafers requires a complete understanding of the deformation and removal mechanism. In this study, molecular dynamics (MD) simulations were carried out to investigate the origins of the differences in elastic–plastic deformation characteristics of the SiC polytypes, including 3C-SiC, 4H-SiC and 6H-SiC, during nanoindentation. The atomic structures, pair correlation function and dislocation distribution during nanoindentation were extracted and analyzed. The main factors that cause elastic–plastic deformation have been revealed. The simulation results show that the deformation mechanisms of SiC polytypes are all dominated by amorphous phase transformation and dislocation behaviors. Most of the amorphous atoms recovered after completed unload. Dislocation analysis shows that the dislocations of 3C-SiC are mainly perfect dislocations during loading, while the perfect dislocations in 4H-SiC and 6H-SiC are relatively few. In addition, 4H-SiC also formed two types of stacking faults. Full article

(This article belongs to the Special Issue Micro/Nano-Machining: Fundamentals and Recent Advances)

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13 pages, 4211 KiB

Open AccessArticle

A Durable Magnetic Superhydrophobic Melamine Sponge: For Solving Complex Marine Oil Spills

by Hanmo Si, Qingwang Liu, Zhenzhong Fan, Biao Wang, Qilei Tong and Mengqi Lin

Nanomaterials 2022, 12(14), 2488; https://doi.org/10.3390/nano12142488 - 20 Jul 2022

Cited by 7 | Viewed by 2114

Abstract

The problem of offshore oil leakage has wreaked havoc on the environment and people’s health. A simple and environmentally friendly impregnation method combined with marine mussel bionics was used to address this issue. Using the viscosity of polydopamine (PDA), nano- Fe₃O [...] Read more.

The problem of offshore oil leakage has wreaked havoc on the environment and people’s health. A simple and environmentally friendly impregnation method combined with marine mussel bionics was used to address this issue. Using the viscosity of polydopamine (PDA), nano- Fe₃O₄ and WS₂ adhered to the framework of the melamine sponge (MS), and then the magnetic sponge was modified with n-octadecanethiol (OTD), and finally the superhydrophobic magnetic melamine sponge (mMS) was prepared. The modified sponge has superhydrophobicity (WCA, 156.8° ± 1.18°), high adsorbability (40~100 g°g⁻¹), recyclability (oil adsorbability remains essentially unchanged after 25 cycles), efficient oil–water separation performance (>98%), and can quickly separate oil on the water’s surface and underwater. Furthermore, the modified sponge exhibits excellent stability and durability under harsh operating conditions such as strong sunlight, strong acid, strong alkali, and high salt, and can control the direction of the sponge’s movement by loading a magnetic field. To summarize, mMS has many potential applications as a new magnetic adsorption material for dealing with complex offshore oil spill events. Full article

(This article belongs to the Special Issue Current Review in Nanofabrication and Nanomanufacturing)

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9 pages, 3581 KiB

Open AccessArticle

Comparative Research on the Thermophysical Properties of Nano-Sized La₂(Zr_0.7Ce_0.3)₂O₇ Synthesized by Different Routes

by Yue Wang, Bohuai Shao, Boyan Fu, Binglin Zou and Chunjie Wang

Nanomaterials 2022, 12(14), 2487; https://doi.org/10.3390/nano12142487 - 20 Jul 2022

Cited by 2 | Viewed by 1531

Abstract

La₂(Zr_0.7Ce_0.3)₂O₇ has been regarded as an ideal candidate for the next generation of thermal barrier coatings (TBCs) due to its prominent superiority. In this paper, the nano-sized La₂(Zr_0.7Ce_0.3) [...] Read more.

La₂(Zr_0.7Ce_0.3)₂O₇ has been regarded as an ideal candidate for the next generation of thermal barrier coatings (TBCs) due to its prominent superiority. In this paper, the nano-sized La₂(Zr_0.7Ce_0.3)₂O₇ was synthesized using two different synthetic routes: sol-gel and hydrothermal processes. Various techniques were utilized to assess the differences in the relevant thermophysical properties created by the different synthetic methods. According to the investigations, both samples exhibited pyrochlore structures with an excellent thermal stability. The sample synthesized via the hydrothermal method showed a more uniform particle size and morphology than that obtained through the sol-gel technique. The former also possessed a better sinter-resistance property, a more outstanding TEC (thermal expansion coefficient) and thermal conductivity, and a larger activation energy for crystal growth than the latter. The micro-strain of both samples showed an interesting change as the temperature increased, and 1200 °C was the turning point. Additionally, relative mechanisms were discussed in detail. Full article

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TG−DSC curves of dried powders: (a) LZ7C3−HT; (b) LZ7C3−SG. Full article ">Figure 2
XRD patterns of LZ7C3−HT (a) and LZ7C3−SG (b) calcined at different temperatures; XRD patterns (c) and Raman spectra (d) of both samples calcined at 1300 °C. Full article ">Figure 3
Relative densities (a) and volume shrinkages (b) of LZ7C3−HT and LZ7C3−SG bodies under different temperatures. Full article ">Figure 4
SEM images of as-prepared powders and compacted bodies calcined at 1400 °C of LZ7C3−HT (a,c) and LZ7C3−SG (b,d). Full article ">Figure 5
Plots of βcosθ vs. 2sinθ for various peaks (hkl) under different temperatures: (a) LZ7C3−HT; (b) LZ7C3−SG. Full article ">Figure 6
Relation between the crystal size and temperature plots of ln (Dt/D0) against 1000/T. Full article ">Figure 7
TECs (a) and thermal conductivities (b) of LZ7C3−HT and LZ7C3−SG as functions of temperature. Full article ">

11 pages, 2676 KiB

Open AccessArticle

Mechanism for the Intercalation of Aniline Cations into the Interlayers of Graphite

by Yifan Guo, Ying Li, Wei Wei, Junhua Su, Jinyang Li, Yanlei Shang, Yong Wang, Xiaoling Xu, David Hui and Zuowan Zhou

Nanomaterials 2022, 12(14), 2486; https://doi.org/10.3390/nano12142486 - 20 Jul 2022

Cited by 4 | Viewed by 2148

Abstract

The dynamic behaviors of aniline cation (ANI⁺) intercalating into graphite interlayers are systematically studied by experimental studies and multiscale simulations. The in situ intercalation polymerization designed by response surface methods implies the importance of ultrasonication for achieving the intercalation of ANI [...] Read more.

The dynamic behaviors of aniline cation (ANI⁺) intercalating into graphite interlayers are systematically studied by experimental studies and multiscale simulations. The in situ intercalation polymerization designed by response surface methods implies the importance of ultrasonication for achieving the intercalation of ANI⁺. Molecular dynamics and quantum chemical simulations prove the adsorption of ANI⁺ onto graphite surfaces by cation–π electrostatic interactions, weakening the π–π interactions between graphene layers. The ultrasonication that follows breaks the hydrated ANI⁺ clusters into individual ANI⁺. Thus, the released positive charges of these dissociative cations and reduced steric hindrance significantly improve their intercalation ability. With the initial kinetic energy provided by ultrasonic field, the activated ANI⁺ are able to intercalate into the interlayer of graphite. This work demonstrates the intercalation behaviors of ANI⁺, which provides an opportunity for investigations regarding organic-molecule-intercalated graphite compounds. Full article

(This article belongs to the Special Issue Theoretical Calculation and Molecular Modeling of Nanomaterials)

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Graphical abstract
Full article ">Figure 1
Effect of the exfoliation of graphene (Y) to ultrasonication power (X1) and time (X2) when the graphite is (a) small flaky graphite (X3 = SfG), (b) large flaky graphite (X3 = LfG), and (c) microcrystalline graphite (X3 = MG). Full article ">Figure 2
MD simulations of ANI+ adsorbed on the surface of bilayer graphene. (a–c) Snapshots of the adsorption process with simulated times of (a) 0 ns, (b) 5 ns, and (c) 10 ns. ANI+ within 0.5 nm from graphene is presented using the van der Waals surface model (red), as the others were the transparent line model. H2O and Cl− are hidden to facilitate observation. (d) Radial distribution function between the centroid of ANI+ and carbon atoms in bilayer graphene, and (insert) their adsorption model. (e,f) van der Waals interaction energy between (e) ANI+ and bilayer graphene, and (f) graphene layers in bilayer graphene. Full article ">Figure 3
First-principles simulations of the adsorption models. Electronic density difference between bilayer graphene and (a,c) ANI+, and (b,d) ANIm with an isovalue of 0.003. Full article ">Figure 4
RESP-mapped van der Waals surface. (a) ANI+, (b) ANIm. Full article ">Figure 5
Interactions between ANI+ and H2O in solution. (a) Solvent-accessible surface area of ANI+ in solution; (b) number of hydrogen bonds formed between ANI+ and H2O; (c) radial distribution function between ANI+ and H2O; (d) RESP mapped van der Waals surface of ANI+ and H2O; (e) number of hydrogen bonds between ANI+ and H2O influenced by simulated ultrasonication; (f) schematics of the activated ANI+. Full article ">Figure 6
MD simulations of ANI+ intercalating into the interlayer of bilayer graphene. (a–c) Snapshots of the aniline cations intercalating into the interlayer of bilayer graphene with a simulated time of (a) 0 ps, (b) 0.3 ps, and (c) 3 ps. Water molecules are hidden in the snapshots. The graphene is presented using paper chain model to exhibit its distortion. The intercalating aniline cations are presented using a van der Waals surface model (green). (d) RMSD curves of bilayer graphene intercalated by aniline cations with different initial kinetic energy; (e) relationships between the maximal RMSD values and the initial kinetic of aniline cations. Full article ">

30 pages, 8293 KiB

Open AccessReview

Biomimetic Nanomaterials: Diversity, Technology, and Biomedical Applications

by Kamil G. Gareev, Denis S. Grouzdev, Veronika V. Koziaeva, Nikita O. Sitkov, Huile Gao, Tatiana M. Zimina and Maxim Shevtsov

Nanomaterials 2022, 12(14), 2485; https://doi.org/10.3390/nano12142485 - 20 Jul 2022

Cited by 21 | Viewed by 5340

Abstract

Biomimetic nanomaterials (BNMs) are functional materials containing nanoscale components and having structural and technological similarities to natural (biogenic) prototypes. Despite the fact that biomimetic approaches in materials technology have been used since the second half of the 20th century, BNMs are still at [...] Read more.

Biomimetic nanomaterials (BNMs) are functional materials containing nanoscale components and having structural and technological similarities to natural (biogenic) prototypes. Despite the fact that biomimetic approaches in materials technology have been used since the second half of the 20th century, BNMs are still at the forefront of materials science. This review considered a general classification of such nanomaterials according to the characteristic features of natural analogues that are reproduced in the preparation of BNMs, including biomimetic structure, biomimetic synthesis, and the inclusion of biogenic components. BNMs containing magnetic, metal, or metal oxide organic and ceramic structural elements (including their various combinations) were considered separately. The BNMs under consideration were analyzed according to the declared areas of application, which included tooth and bone reconstruction, magnetic and infrared hyperthermia, chemo- and immunotherapy, the development of new drugs for targeted therapy, antibacterial and anti-inflammatory therapy, and bioimaging. In conclusion, the authors’ point of view is given about the prospects for the development of this scientific area associated with the use of native, genetically modified, or completely artificial phospholipid membranes, which allow combining the physicochemical and biological properties of biogenic prototypes with high biocompatibility, economic availability, and scalability of fully synthetic nanomaterials. Full article

(This article belongs to the Special Issue Biomimetic and Biogenic Multifunctional Nanomaterials)

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20 pages, 4344 KiB

Open AccessFeature PaperArticle

Stable Dried Catalase Particles Prepared by Electrospraying

by Corinna S. Schlosser, Steve Brocchini and Gareth R. Williams

Nanomaterials 2022, 12(14), 2484; https://doi.org/10.3390/nano12142484 - 20 Jul 2022

Cited by 1 | Viewed by 2152

Abstract

Therapeutic proteins and peptides are clinically important, offering potency while reducing the potential for off-target effects. Research interest in developing therapeutic polypeptides has grown significantly during the last four decades. However, despite the growing research effort, maintaining the stability of polypeptides throughout their [...] Read more.

Therapeutic proteins and peptides are clinically important, offering potency while reducing the potential for off-target effects. Research interest in developing therapeutic polypeptides has grown significantly during the last four decades. However, despite the growing research effort, maintaining the stability of polypeptides throughout their life cycle remains a challenge. Electrohydrodynamic (EHD) techniques have been widely explored for encapsulation and delivery of many biopharmaceuticals. In this work, we explored monoaxial electrospraying for encapsulation of bovine liver catalase, investigating the effects of the different components of the electrospraying solution on the integrity and bioactivity of the enzyme. The catalase was successfully encapsulated within polymeric particles made of polyvinylpyrrolidone (PVP), dextran, and polysucrose. The polysorbate 20 content within the electrospraying solution (50 mM citrate buffer, pH 5.4) affected the catalase loading—increasing the polysorbate 20 concentration to 500 μg/mL resulted in full protein encapsulation but did not prevent loss in activity. The addition of ethanol (20% v/v) to a fully aqueous solution improves the electrospraying process by reducing surface tension, without loss of catalase activity. The polymer type was shown to have the greatest impact on preserving catalase activity within the electrosprayed particles. When PVP was the carrier there was no loss in activity compared with fresh aqueous solutions of catalase. The optimum particles were obtained from a 20% w/v PVP or 30% w/v PVP-trehalose (1:1 w/w) solution. The addition of trehalose confers stability advantages to the catalase particles. When trehalose-PVP particles were stored at 5 °C, enzymatic activity was maintained over 3 months, whereas for the PVP-only analogue a 50% reduction in activity was seen. This demonstrates that processing catalase by monoaxial electrospraying can, under optimised conditions, result in stable polymeric particles with no loss of activity. Full article

(This article belongs to the Special Issue Nanoencapsulation and Nanocoating of Bioactives of Application Interest in Food, Nutraceuticals and Pharma)

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9 pages, 2825 KiB

Open AccessArticle

Study on Nanoporous Graphene-Based Hybrid Architecture for Surface Bonding

by Xiaohui Song, Mingxiang Chen, Jingshuang Zhang, Rui Zhang and Wei Zhang

Nanomaterials 2022, 12(14), 2483; https://doi.org/10.3390/nano12142483 - 20 Jul 2022

Cited by 4 | Viewed by 1637

Abstract

Graphene-copper nanolayered composites have received research interest as promising packaging materials in developing next-generation electronic and optoelectronic devices. The weak van der Waal (vdW) contact between graphene and metal matrix significantly reduces the mechanical performance of such composites. The current study describes a [...] Read more.

Graphene-copper nanolayered composites have received research interest as promising packaging materials in developing next-generation electronic and optoelectronic devices. The weak van der Waal (vdW) contact between graphene and metal matrix significantly reduces the mechanical performance of such composites. The current study describes a new Cu-nanoporous graphene-Cu based bonding method with a low bonding temperature and good dependability. The deposition of copper atoms onto nanoporous graphene can help to generate nanoislands on the graphene surface, facilitating atomic diffusion bonding to bulk copper bonding surfaces at low temperatures, according to our extensive molecular dynamics (MD) simulations on the bonding process and pull-out verification using the canonical ensemble (NVT). Furthermore, the interfacial mechanical characteristics of graphene/Cu nanocomposites can be greatly improved by the resistance of nanostructure in nanoporous graphene. These findings are useful in designing advanced metallic surface bonding processes and graphene-based composites with tenable performance. Full article

(This article belongs to the Special Issue Mechanics of Micro- and Nano-Size Materials and Structures)

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Atomic configurations. (a) Cu-nanoporous graphene composite model; (b) Cu atoms deposition onto the nanoporous graphene surface; (c) Cu-nanoporous graphene-Cu thermocompression bonding; (d) Pull-out simulation model. Full article ">Figure 2
Atomic configurations of Cu atoms deposition onto the graphene at various stages. (a) Filling of nanopores at the initial stage; (b) Insular growth to nanoislands; (c) Further growing of nanoislands; (d) Joining with neighboring nanoislands. Full article ">Figure 3
Cross-section configurations of Cu-nanoporous graphene-Cu during the bonding process at various stages. (a) Contacting of bonding surface; (b) Compression deformation of the nanoislands; (c) Final bonding structure. Full article ">Figure 4
The pull-out force changes as a function of the sliding distance for the graphene/Cu composite with and without nanoporous. Full article ">Figure 5
The displacement of copper atoms at the interface of graphene/Cu nanocomposites with various sliding distances. Full article ">Figure 6
The maximum pull-out force changes as a function of the number of deposited copper atoms for the graphene/Cu composite. Full article ">Figure 7
The maximum pull-out force changes vs. nanoporous diameters. Full article ">

13 pages, 4848 KiB

Open AccessArticle

Covalent Organic Framework/Polyacrylonitrile Electrospun Nanofiber for Dispersive Solid-Phase Extraction of Trace Quinolones in Food Samples

by Jinghui Zhou, An Chen, Hongying Guo, Yijun Li, Xiwen He, Langxing Chen and Yukui Zhang

Nanomaterials 2022, 12(14), 2482; https://doi.org/10.3390/nano12142482 - 20 Jul 2022

Cited by 14 | Viewed by 2425

Abstract

The extraction of quinolone antibiotics (QAs) is crucial for the environment and human health. In this work, polyacrylonitrile (PAN)/covalent organic framework TpPa–1 nanofiber was prepared by an electrospinning technique and used as an adsorbent for dispersive solid-phase extraction (dSPE) of five QAs in [...] Read more.

The extraction of quinolone antibiotics (QAs) is crucial for the environment and human health. In this work, polyacrylonitrile (PAN)/covalent organic framework TpPa–1 nanofiber was prepared by an electrospinning technique and used as an adsorbent for dispersive solid-phase extraction (dSPE) of five QAs in the honey and pork. The morphology and structure of the adsorbent were characterized, and the extraction and desorption conditions for the targeted analytes were optimized. Under the optimal conditions, a sensitive method was developed by using PAN/TpPa–1 nanofiber as an adsorbent coupled with high-performance liquid chromatography (HPLC) for five QAs detection. It offered good linearity in the ranges of 0.5–200 ng·mL⁻¹ for pefloxacin, enrofloxacin, and orbifloxacin, and of 1–200 ng·mL⁻¹ for norfloxacin and sarafloxacin with correlation coefficients above 0.9946. The limits of detection (S/N = 3) of five QAs ranged from 0.03 to 0.133 ng·mL⁻¹. The intra-day and inter-day relative standard deviations of the five QAs with the spiked concentration of 50 ng·mL⁻¹ were 2.8–4.0 and 3.0–8.8, respectively. The recoveries of five QAs in the honey and pork samples were 81.6–119.7%, which proved that the proposed method has great potential for the efficient extraction and determination of QAs in complex samples. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sample Pretreatment)

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Schematic diagram of the preparation of PAN/TpPa–1 nanofiber and used as a dSPE adsorbent of QAs. Full article ">Figure 2
SEM images of TpPa–1 (A), pure PAN (B), PAN/TpPa–1 (C,D) nanofiber. Full article ">Figure 3
FT-IR spectra of Tp, Pa–1, and COF TpPa–1. Full article ">Figure 4
XRD patterns of TpPa–1, PAN/TpPa–1 nanofiber, pure PAN nanofiber, and simulation of TpPa–1. Full article ">Figure 5
Effect of amount of PAN/TpPa–1 nanofiber (A), types of desorption solvent (B), desorption time (C), extraction time (D), concentration of NaCl (E), and standard solution pH value (F) on the extraction performance of QAs. Full article ">Figure 6
(A): HPLC-UV chromatograms of (a) honey sample; (b) honey sample after dSPE; (c) honey sample spiked with 100 ng·mL–1 before dSPE; and (d) honey sample spiked 100 ng·mL–1 after dSPE. (B): HPLC-UV chromatograms of (a) pork sample; (b) pork sample after dSPE; (c) pork sample spiked with 100 ng·mL–1 before dSPE; and (d) pork sample spiked 100 ng·mL–1 after dSPE. Full article ">

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Nanomaterials, Volume 12, Issue 14 (July-2 2022) – 195 articles

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