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Using nanostructured materials issued from renewable resources could be the key to the development of good-quality low-cost products that help reduce pollution. Cellulose nanofibrils (CNFs) were obtained by alkaline and bleaching treatments of Amazonian Paricá hardwood sawdust, a waste material from the Brazilian forestry industry. This study evaluated a process consisting in alternating layers of Paricá CNFs and cassava starch to coat standard writing and printing (W&P) papers with a skim-coating method, in which one face of each paper sample is passed over the surface of a suspension containing either CNFs or cassava starch, alternatively. The coated samples were then compared to the uncoated paper in terms of mechanical and surface properties. The mechanical properties of the papers coated with alkaline CNFs showed a declining trend as the number of coating layers increased (from 47 to 31 MPa). The papers coated with starch layers showed improved mechanical performance compared to the samples only coated with alkaline and alkaline bleached CNFs. All the coated samples showed excellent resistance to water degradation. The worst degradation (4%) was observed for the samples coated with a single layer of alkaline CNFs. A significant improvement in surface wettability was observed when gelatinized cassava starch was applied to the paper samples, irrespective of the type of CNFs eventually present on the surface. All in all, these results suggest that using gelatinized cassava starch as an alternating layer between successive CNFs layers on the surface of W&P paper samples may be promising for improving their overall properties. [ABSTRACT FROM AUTHOR]

The June 2024 cover image of the Journal of Materials Science features a paper by Liss et al. titled "Recrystallization of bulk nanostructured magnesium alloy AZ31 after severe plastic deformation: an in situ diffraction study." The image is an artistic representation of nanostructured magnesium alloy AZ31 undergoing heating, showcasing the process of recrystallization in reciprocal space. The paper is part of a Special Issue on "Processing Bulk Nanostructured Materials," which includes a total of 28 articles covering various aspects of severe plastic deformation (SPD) in the processing of bulk nanostructured materials. The Special Issue aims to highlight the enduring significance and resilience of research in this field. Both the paper and the preface of the Special Issue have SharedIt links for easy sharing with readers. [Extracted from the article]

The introduction of nanoparticles (NPs) and nanostructured materials (NSMs) in papermaking originally emerged from the perspective of improving processing operations and reducing material consumption. However, a very broad range of nanomaterials (NMs) can be incorporated into the paper structure and allows creating paper products with novel properties. This review is of interdisciplinary nature, addressing the emerging area of nanotechnology in papermaking focusing on resources, chemical synthesis and processing, colloidal properties, and deposition methods. An overview of different NMs used in papermaking together with their intrinsic properties and a link to possible applications is presented from a chemical point of view. After a brief introduction on NMs classification and papermaking, their role as additives or pigments in the paper structure is described. The different compositions and morphologies of NMs and NSMs are included, based on wood components, inorganic, organic, carbon-based, and composite NPs. In a first approach, nanopaper substrates are made from fibrillary NPs, including cellulose-based or carbon-based NMs. In a second approach, the NPs can be added to a regular wood pulp as nanofillers or used in coating compositions as nanopigments. The most important processing steps for NMs in papermaking are illustrated including the internal filling of fiber lumen, LbL deposition or fiber wall modification, with important advances in the field on the in situ deposition of NPs on the paper fibers. Usually, the manufacture of products with advanced functionality is associated with complex processes and hazardous materials. A key to success is in understanding how the NMs, cellulose matrix, functional additives, and processes all interact to provide the intended paper functionality while reducing materials waste and keeping the processes simple and energy efficient. [ABSTRACT FROM AUTHOR]

This review paper highlights the current toxicological aspects of magnetic nanomaterials in the field of medicine and the environment, conducted through a comprehensive literature review. The main goal was to investigate and analyze the key challenges identified in the literature that enhance the effective utilization of these systems, particularly focusing on magnetic iron oxide (Fe3O4) nanoparticles. We aimed to investigate the factors that influence their intended applications. We sought to understand how the characteristics of the produced NPs could be enhanced to improve their biocompatibility compared to existing samples in the literature. Moreover, we investigated morphological aspects intricately connected to physicochemical characteristics and their prospective applications in biomedicine. Additionally, we assessed the regulatory implications of nanostructured materials. Therefore, the initial aspect of this review delved into the historical evolution of nanoparticles, investigating significant milestones that have influenced the exploration of this technology. We examined the main discoveries, factors influencing the choice of synthesis methods, and the most prevalent approaches for surface functionalization employed by scientists for materials possessing superparamagnetic characteristics, such as iron oxide. The second aspect of the review focused on a survey-based exploration of the global regulation progress concerning superparamagnetic nanoparticles throughout the years. Additionally, we identified the main challenges encountered in establishing safety criteria for the diverse applications under investigation. This encompassed an assessment of the potential impacts of these materials on both human health and the environment. [ABSTRACT FROM AUTHOR]

To find a new type of sensing material with high sensitivity to acetone gas, in this paper, a first-principles method based on density functional theory was used to study the gas-sensing mechanism of perovskite-type ZnSnO3 to acetone. A hydrothermal method was used to prepare perovskite-type ZnSnO3, and perform a gas sensitivity test. Calculated results demonstrate that acetone molecules interacted strongly with the ZnSnO3(001) surface with pre-adsorbed O2− and O−, accompanied by charge transfer that can change the resistance of the material. This phenomenon provides the basis for using ZnSnO3 as an acetone gas-sensitive sensing material. The experimental results showed that the perovskite-type ZnSnO3 has a sheet structure with micro-holes on the surface, which can promote responsivity to acetone gas. The gas sensitivity test indicated the optimal operating temperature is 350 °C, the response/recovery time is 4 s/27 s. The sensitivities of the synthesized ZnSnO3 nanosheet that in this paper to 100 ppm and 10 ppm acetone gas are 125.444 and 8.37, respectively. In the five-week stability and repeatability test, the sensitivity to 10/100 ppm acetone of sheet-like ZnSnO3 sensor could still maintain at 89.64% and 94.74% of the first test result. This study provides theoretical guidance for the development of acetone gas sensors. [ABSTRACT FROM AUTHOR]

Germanium selenide (GeSe), a mono-sulfide compound of group VI elements, has a crystal and semiconductor structure similar to black phosphorus, which means that it is very promising for applications in nanophotonic devices. In this paper, we prepared 5 mg ml−1 GeSe nanosheet suspensions by liquid-phase exfoliation technique and centrifuged the suspensions at different speeds to obtain GeSe nanosheets with different layer numbers to investigate the effect of nanosheet layer numbers on the third-order nonlinear optical properties of GeSe nanosheets. AFM microscopy is used to show that the number of layers in a nanosheet can be controlled using differential centrifugation techniques. The structure and defects of the exfoliated nanosheets were analyzed based on the results of Raman spectroscopy and X-ray energy spectrometry. The open-aperture Z-scan technique revealed that the nonlinear absorption effect of the nanosheet changed from saturation absorption to reverse saturation absorption when the number of nanosheet layers was gradually reduced. The closed-aperture Z-scan technique reveals that the nonlinear refraction effect enhanced when the number of nanosheet layers is gradually reduced. [ABSTRACT FROM AUTHOR]

PET (polyethylene terephthalate) being widely used in the manufacturing of bottles, especially in the beverages industry, has obvious advantages over glass bottles and cans, including but not limited to its transparency, robustness, and light weightiness, etc. However, its permeability is a major concern for scientists as it evidently affects the quality of packaged food, especially beverages. The fact that it easily allows gases like oxygen and carbon dioxide to pass through them makes it less effective and least cost-efficient when compared with its substitutes. Alternatively, if its permeability is ameliorated, this can drastically improve the overall statistics of profits in the beverage industry. This paper attempts to improve the gas barrier property of PET via a reduction in carbon dioxide (CO2) permeation. Through temperature-induced solution processing, WS2 (tungsten disulfide) is disseminated in PET. The decrease in CO2 permeability in WS2 nanosheets/PET composites is assessed. After an 11-h test run, free-standing composite membranes demonstrated a maximum 99.9% permeability decrease at extremely low filler loading (0.005 wt% WS2) in contrast to the polymer. It is interesting to note that WS2 loading over 0.005 wt% completely reduced permeation. High-aspect-ratio WS2, homogenous dispersion inside PET, and jiggling effect surrounding nanosheets per flake have all contributed to the gas flow's winding path's complexity. Through the use of models developed by Bharadwaj, Neilson, Lape, and Cussler, experimental findings have been confirmed. SEM evaluates the dispersion state, and X-ray diffraction has validated the formation of composites. Higher mechanical resilience of WS2 nanosheets/PET composites and adhesion property was demonstrated by tensile testing and tribology technique. [ABSTRACT FROM AUTHOR]

The edge-hydroxylated boron nitride nanosheets (BNNS) not only has excellent thermal stability, electrical properties, but also has high specific surface area, good dispersibility and compatibility. In this paper, edge-hydroxylated BNNS was obtained by stripping hexagonal boron nitride (h-BN) using wet chemical reaction method. The hydroxylated structure of the surface and formation mechanism of BNNS were analyzed, and the optimal controlled conditions were explored by orthogonal test. The results showed that the content of N element in the center of the BNNS (46.44 at. %) is significantly higher than that of B element in the edge of the sheets (33.10 at. %), and the content of O element in the edge of the sheets is nearly 30% higher than that in the center. It indicates that the edge of the BNNS introduces more oxygen than h-BN, the nitrogen atoms at the edge are replaced by oxygen atoms to achieve hydroxylation. When the mass ratio of h-BN and potassium permanganate is 1 g: 5 g, the reaction time is 9 h, and the reaction temperature is 60 °C, the obtained nanosheets have the best hydroxylation and good stripping effect. The average lateral size of the exfoliated nanosheets is 123 nm and only about three layers. [ABSTRACT FROM AUTHOR]

The synthesis of graphene-like transition metal dichalcogenides (TMDs) has attracted great attention because of its excellent photoelectric properties and wide potential applications. Well controlling the preparation and understanding the growth mechanism of these nanomaterials are important for the development of applications with high efficiency. In this paper, we synthesized flower-like tungsten disulfide nanosheets (F-WS2) by reacting tungsten oxide with sulfur vapor. Lots of thin WS2 nanosheets with a thickness of a few nanometers are assembled together from the same center to form a flower-like microsphere with a diameter of ~ 1–4 µm. These nanostructures have been characterized by various techniques, and the growth mechanism has been investigated. The flow rate of oxygen (or atmosphere with oxygen) is found to play a key role in the growth to mediate the morphology to obtain these flower-like WS2 nanosheets, while only WS2 nanoparticles (N-WS2) are grown without oxygen flow. These F-WS2 show excellent photocatalytic activities, which are also better than those of N-WS2. So this method confirms the feasibility of oxygen regulated growth of similar TMDs materials, which is also important for the development of photocatalysts with high efficiency. [ABSTRACT FROM AUTHOR]

The development of pharmaceutical analytical techniques is one of the most crucial steps in drug development and quality control. The pharmaceuticals serve their intent only if their content is labeled, free from impurities, and are administered in an appropriate amount. Thus, an accurate, selective, low-cost, and fast analytical tool is highly required. Carbon nanodots (CDs), as emerging luminescent nanomaterials in analytical applications, play a significant role in offering low detection limit, superior selectivity, high sensitivity, low-cost precursors, biocompatible, and facile preparation protocols. Recently, many papers have been reported on the quantification and detection of various active pharmaceutical ingredients using CDs. Owing to the luminescence of CDs, a big concern is given to fluorescence-based probes. This review article highlights the physical and chemical properties of CDs, their synthesis approaches, surface functionalization, detection mechanisms, and several detection platforms, such as fluorescence, electrochemical, electrochemiluminescence, colorimetry, and surface plasmon resonance for pharmaceutical analysis based on CDs. [ABSTRACT FROM AUTHOR]

In this study, an efficient visible light responsive MIL-125(Ti)/ZnIn2S4 hybrid structure (MIL-1.2/ZIS) was synthesized through two-step method with improved photocatalytic H2-evolution performance. The MIL-1.2/ZIS nanocomposites could retained the characteristic features including the highly surface area of metal organic frameworks and the hierarchical sheet-like structure of ZnIn2S4. The optimal sample could exhibit the H2 generation rate of 873.4 μmol g−1·h−1, and the improved photocatalytic activity could be ascribed to the well-matched band structure and the formation of hybrid interfaces, which could lead to the effective charge transfer and separation of photo-excited electron–hole pairs. We hope this paper could broad the potential utilization of MOF-based nanocomposites in photocatalytic energy conversion fields. [ABSTRACT FROM AUTHOR]

Recently, the core–shell nanostructured materials have gained considerable attention due to their nano-scale size effect, well-controlled structure, and tunable physicochemical features which extend their applications in many hot research topics. This review emphasizes their applications in terms of five major fields: catalysis, adsorption, sensing, membrane separation and biomedical application, which render them promising candidates for diverse practical manipulations such as environmental remediation, gas separation and storage, flexible electronic devices and therapeutic vehicles. This paper makes a comprehensive analysis and discussion on the considerable and representative research in each field, in order to provide the reference for the relevant research works by taking the advantages of structural stability and high dispersive active phases of core–shell materials. Finally, the article offers the future prospective application of the core–shell nanomaterials to envision that new breakthrough will be yield in this field. [ABSTRACT FROM AUTHOR]

In the field of photocatalysis, the recombination of photogenerated holes and electrons is still an urgent problem to be solved. Among many measures, constructing heterojunction is one of the commonly used methods to adjust the carrier transfer path and accelerate the electron transfer. In this paper, Fe2O3/NiS p–n heterojunction composite catalyst was synthesized by solvothermal method. Through XRD, SEM and XPS characterization and analysis, it was found that the composite catalyst was composed of NiS nanoparticles and hexagonal Fe2O3 nanosheets. The specific surface area test results showed that Fe2O3/NiS had a larger specific surface area, which could provide more active sites for the H2 production reaction. By adjusting the ratio between Fe2O3 and NiS, the optimal composite photocatalyst was obtained. The hydrogen production rate reached 5.82 mmol g−1 h−1, which was 58.2× that of single Fe2O3 and 2.7× that of single NiS. The NiS p-type semiconductor and Fe2O3n-type semiconductor were successfully coupled. Under the action of the p–n heterojunction interface and the built-in electric field, the photogenerated electrons and holes of the composite catalyst could be quickly transferred and separated. This result was also confirmed by a series of characterizations such as photoluminescence spectrum and photoelectrochemical experiments. Fe2O3 and NiS formed p–n heterojunctions, and the mixed interface structure between them provided a new hydrogen-producing active center for each. Moreover, the construction of p–n heterojunction promoted the separation of electrons (e−) and holes (h+), so that Fe2O3/NiS exhibited excellent hydrogen evolution performance. [ABSTRACT FROM AUTHOR]

This review paper provides a recent overview of current international research that is being conducted into the functional properties of cellulose as a nanomaterial. A particular emphasis is placed on fundamental and applied research that is being undertaken to generate applications, which are now becoming a real prospect given the developments in the field over the last 20 years. A short introduction covers the context of the work, and definitions of the different forms of cellulose nanomaterials (CNMs) that are most widely studied. We also address the terminology used for CNMs, suggesting a standard way to classify these materials. The reviews are separated out into theme areas, namely healthcare, water purification, biocomposites, and energy. Each section contains a short review of the field within the theme and summarizes recent work being undertaken by the groups represented. Topics that are covered include cellulose nanocrystals for directed growth of tissues, bacterial cellulose in healthcare, nanocellulose for drug delivery, nanocellulose for water purification, nanocellulose for thermoplastic composites, nanocellulose for structurally colored materials, transparent wood biocomposites, supercapacitors and batteries. [ABSTRACT FROM AUTHOR]

The major challenges in the commercialization of spintronic devices lie in the high-dimensional materials with low spin-current generation efficiency and expensive fabrication processes. Recent discovery on the magnetoresistance (MR) phenomenon of graphene nanosheets could suggest that graphene-based materials can be excellent materials for spintronic devices. To develop two-dimensional materials with high MR at the low magnetic field and room temperature, we design and develop hybrid graphene nanosheets by using the matrix-assisted pulsed laser evaporation (MAPLE) technique. FeCo nanoparticles (NPs) are deposited onto the reduced graphene oxide (rGO) nanosheets in a stoichiometric manner by the MAPLE process. The density and size of FeCo NPs on rGO can be simply adjusted by varying the deposition time (t). Most importantly, with a limited FeCo ratio (0.4 at.%), MAPLE-prepared FeCo/rGO hybrid nanosheets display an MR phenomenon (MR up to 0.7%) at the low magnetic field (10 kOe) and room temperature. In this paper, we demonstrate that the MAPLE process can be used to produce hybrid graphene nanosheets with MR properties. The results of this work can contribute to the development of spintronic devices, e.g., ultra-thin MR sensors. [ABSTRACT FROM AUTHOR]

The replacing and surpassing of some functions of traditional metal-based photocatalysts by low-cost and high-efficiency non-metal semiconductor materials have become a research hotspot in functional materials. In this paper, the ultra-thin nanoporous g-C3N4 nanosheets were successfully embedded with highly dispersed S quantum dots (S QDs) by ultrasonic-assisted in-situ growth method, which originates from the disproportionation reaction of sodium thiosulfate. The formation of the composite was proved by XRD, XPS, AFM, TEM and HRTEM and proved that S QDs with a size of 1–3.5 nm were uniformly embedded in the surface of ultra-thin nanoporous g-C3N4, in which a tight and uniform 0D/2D heterojunction structure was designed and built. Meanwhile, the photocatalytic mechanism was investigated. It showed that the tight Z-Scheme heterojunction structure formed between S QDs and g-C3N4 improved the redox activity as well as the transfer ability of photogenerated electron holes. The system exhibited excellent photocatalytic efficiency that the complete degradation of RhB was achieved within 90 min under visible-light irradiation and revealed high stability. We believe that this research is important for the development of low-cost and efficient non-metal photocatalysts. [ABSTRACT FROM AUTHOR]

The application of nanomaterials in the construction field is allowing the development of smart, green, durable and more efficient buildings. Among the most widely researched nanomaterials are nanosized cool pigments, which are being enforced to achieve thermal and energy-efficient façades, with the development of high reflectance and retro-reflectance coatings. Their peculiar optical and catalytic activity turns nanomaterials into suitable candidates to be used as dark coloured high solar reflectance without affecting aesthetic characteristics, thus improving the durability of coatings. The objective of this paper is to review the state-of-the-art on the benefits of using high reflectance nanopigments as coatings in building façades and their production and synthesis processes. It is thus divided into three main topics: (i) the benefits of using nanopigments on façades, (ii) the most important nanomaterials used as cool pigments and (iii) the main methods of synthesizing nanopigments. One expects that the study of near-infrared nanopigmentation synthesis processes will be able to promote and disseminate the use of nanotechnology in construction, assessing the production problems and limitation and thus helping to disseminate new products by reducing production costs and increase availability. [ABSTRACT FROM AUTHOR]

In this work, a novel nanostructure of gold nanosheets (NSs)-decorated TiO2 nanocolumns (NCs) coated on carbon fiber (Au NSs-TiO2 NCs/CF) is designed and fabricated. The structure and morphology can be adjusted from Tanghulu-like to sausage-shaped with the final concentration of chloroauric ions in the reaction solution. Au NSs-TiO2 NCs/CF have been proven to be an excellent SERS substrate with a high analytical enhancement factor, good uniformity, and great stability. Most importantly, SERS experiments can be carried out on one strand of Au NSs-TiO2 NCs/CF with the aid of a Raman confocal microscope. These Tanghulu-like and sausage-shaped Au NSs-TiO2 NCs/CF have great potential in SERS analysis of trace samples. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis of ligand-free Au nanoclusters (NCs)/g-C3N4 ultra-thin nanosheets (NSs) composite via a facile wet-impregnation method with post-annealing. On the one hand, post-annealing was used for the exfoliation of multi-layered g-C3N4 to obtain ultra-thin NSs; on the other hand, after Au25(Cys)18 NCs were loaded, post-annealing was further adopted to remove the ligands to obtain clean surface on Au NCs. It is demonstrated that the loaded Au NCs were aggregating resistant by post-annealing. Constructing heterojunctions with appropriate inter-band structures between the ligand-free Au NCs and the ultra-thin g-C3N4 NSs, along with the mono-distribution of the Au NCs and their intimate contact with g-C3N4 NSs ensured the smooth interfacial charge transfer. As a result, the composite photocatalysts exhibited efficient visible-light-induced photocatalytic H2 generation, mainly due to the local electric field enhancement induced by excitation of Au NCs under visible light and the improved charge separation in g-C3N4. This work provides a general strategy for the synthesis of noble metal NCs based composites with clean surface as the efficient photocatalysts for solar energy conversion. A stepwise post-annealing strategy is exploited to prepare g-C3N4 ultra-thin nanosheets modified with highly dispersed ligand-free Au nanoclusters for efficient photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

In this paper, a thorough study is dedicated to the manipulating of nanostructured zirconia thin films prepared by a sol-gel process with the focus on the wetting properties. It is observed that by engineering the amount of cetyltrimethylammonium bromide [[N(CH3)3] Br] (CTAB) and polyethylene glycol (PEG) in zirconium chloride precursor solution, the novel agar-like morphology with random orientation can be grown. Different morphologies are observed by changing the amount of PEG in the solution. All the prepared samples in this method show tetragonal phase after annealing at 500 °C for 1 h. The crystallite sizes have a direct correlation with the ratio of lattice parameters. The optical band gap is estimated by Kubelka-Munk method. Modified ZrO2 thin films at an optimum ratio of PEG to CTAB annealed at 500 °C and present water contact angle lower than 3° (without UV illumination) which indicates their superhydrophilic properties. The analytical results of SEM images of samples annealed at 500 °C are also reported. Spreading and wicking of liquid through the nanochannels which are formed in the vacant spaces between nanorods lead to superior wetting property. Annealing temperature also strongly affects the wettability of agar-like zirconia thin films. Agar-like ZrO2 thin films are obtained with superhydrophilic behavior by annealing at 500 °C. Similar agar-like morphology is also observed with hydrophobic character by annealing at 200 °C. The introduced preparation method in this paper provides an easy route to fabricate superhydrophilic agar-like ZrO2 thin films without further processing. [ABSTRACT FROM AUTHOR]

As a new two-dimensional material, MXene has caused extensive research in field of supercapacitor, electromagnetic shielding, strain sensing field due to its excellent mechanical properties and electrical conductivity. MXene with good water dispersibility can be used as an ideal nano-material to enhance the conductivity of hydrogels. However, MXene is easy to accumulate in the hydrogel system, and there are rare articles on MXene hydrogels. In this paper, we combine cellulose nanocrystals (CNCs) and MXene to prepare CNC/MXene nanosheets and take advantage of CNC's excellent dispersibility in water and the electrostatic repulsion between CNCs to avoid the accumulating of MXene and enhance the mechanical properties of the hydrogel. Based on it, we prepared a physical–chemical double crosslinking and double-network CNC/MXene hydrogel by in situ polymerization and cycle freeze-thaw method. The CNC/MXene hydrogel we prepared exhibited excellent mechanical properties; it could be stretched to 7 times its original length and could reach 1.025 MPa tensile stress. When the compression strain was 80%, the compression stress could reach 1.1 MPa. After unloading the compression pressure, it could rapidly return to its original length within 0.17 s, which would impact greatly on the practical application of CNC/MXene hydrogel. What's more, the conductivity of it was up to 0.4 S/m and the thermal conductivity was 0.38 W/mK. So, the hydrogel prepared by us has a wide range of application prospects in the fields of human motion monitoring, electronic skin, man–machine interface, etc. [ABSTRACT FROM AUTHOR]

Carbon-based luminescent nanomaterials have attracted much attention in the biomedical field. Compared to traditional photoluminescent materials (such as rare earth-based semiconductors and organic dyes), they have excellent biocompatibility, low toxicity, excellent optical stability and site-targeting properties in addition to their low cost and environmentally friendly features. Carbon dots, a typical carbon-based luminescent material, have great application potential in biomedicine, biological imaging and optoelectronics. Actual biological imaging, however, uses low-level photon scattering and light absorption to avoid self-fluorescence by the target tissues, requiring the light waves to have strong tissue penetration ability. Long wavelength (red and near-infrared) is known to have strong tissue penetration. However, carbon dots in the long wavelength region give a low quantum yield. Thus, obtaining long wavelength-emitting carbon dots with high quantum yield is a big challenge in practical bioimaging and phototherapy. In this paper, recent progress in the development of long wavelength, strongly luminescence-emitting carbon dots, the mechanisms and methods to regulate their optical properties and improve their quantum yield are reviewed. Recent applications of carbon dots in biosensing, bioimaging and therapy are described. Finally, the future challenges and prospects of long wavelength carbon-based luminescent materials are discussed. [ABSTRACT FROM AUTHOR]

The combination of conductive material and flexible material is an unavoidable problem in the preparation of flexible sensor, but uniform combination of the materials in micro- or nanostructure is difficult. Coaxial electrospinning is an effective way to realize the combination, which is very strict for the solutions and the synthesis conditions. In this paper, composite pH-sensitive sensors were developed by coaxial electrospinning of polyaniline (PANI) and polyurethane (PU) into core–shell fibers. PU improved the mechanical properties of the sensors. The mechanical properties and conductivity of the sensor can be changed through adjusting the proportion of PANI and PU. By chronopotentiometry in buffer solutions, the sensor worked linearly in the pH range of 2–7 with the sensitivity of − 60 mV/pH and pH change below 0.2 can be detected. It was also proved that the sensor can resist the influence from the changes in temperature, detection time and deformation of the sensor, ensuring the stability in pH detection. Further, by attaching to skin, our sensor showed the response to the pH of small amount of sweat on the skin surface, which suggested the possibility in wearable devices. [ABSTRACT FROM AUTHOR]

A modified thermodynamic approach to describe melting in isolated nanoscale materials is suggested. The Gibbs free energy change of nanoscale alloy particles is modeled as a function of composition, temperature and nucleus and particle sizes. Cu–Ni has been chosen as a model system due to the availability of thermodynamic data within the high-temperature interval 1300–1600 K. For the first time, "melting loops" in the temperature–composition phase diagram were calculated for nanoparticle of 25 and 80 nm, respectively. It is shown that such loops represent the equilibrium two-phase solid–liquid states and do not coincide with the limiting solubility curves—the solidus and the liquidus. This new finding leads to the "melting loop" concept concerning phase diagrams of nanoscale alloys introduced in this paper. It is found that Cu–Ni nanoparticles can melt in different ways, whereas the dominant transition mechanism is surface-induced melting that initiates from the surface and then proceeds toward the core region. The decrease in size causes also a change of the melting temperature, the temperature width of the phase transition, the solubility limit, the concentration width of the melting loop as well as a change of the shape and slope of the equilibrium curves of the two-phase region of the phase diagram. As expected, when the size of the nanoscale particle increases, the solidus temperature increases and the size-dependent phase diagram approaches the bulk phase diagram. [ABSTRACT FROM AUTHOR]

Synthesis, characterization, and application of Ce0.9Ln0.05Ag0.05O2−δ materials (where, Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, Er) for the thermochemical conversion of CO2 reported in this paper. The Ce0.9Ln0.05Ag0.05O2−δ materials were synthesized by using an ammonium hydroxide-driven co-precipitation method. The derived Ce0.9Ln0.05Ag0.05O2−δ materials were characterized via powder X-ray diffraction, scanning electron microscope, and electron diffraction spectroscopy. The characterization results indicate the formation of spherically shaped Ce0.9Ln0.05Ag0.05O2−δ nanostructured particles. As-prepared Ce0.9Ln0.05Ag0.05O2−δ materials were further tested toward multiple CO2 splitting cycles by utilizing a thermogravimetric analyzer. The results obtained indicate that all the Ce0.9Ln0.05Ag0.05O2−δ materials produced higher quantities of O2 and CO than the previously studied pure CeO2 and lanthanide-doped ceria materials. Overall, the Ce0.911La0.053Ag0.047O1.925 showed the maximum redox reactivity in terms of O2 release (72.2 μmol/g cycle) and CO production (136.6 μmol/g cycle). [ABSTRACT FROM AUTHOR]

In this review, recent progress in the mechanical, thermal and interfacial properties of graphene/CNT multiphase polymer composites is examined. Progress in the mechanical and thermal properties of CNT (1D) and graphene (2D) nanostructure materials is also reviewed and compared. Furthermore, this review highlights the improvements in the mechanical, thermal and interfacial properties of two- and three-phase composites, owing to the addition of graphene/CNT. In particular, analysis of several notable papers on hybrid composites (graphene/CNT) provides an intensive review of synergetic effects on the overall properties of the corresponding composites. This holistic review describes an improved interface between fibers and a nanofiller-reinforced matrix. Although the presence of nanofillers even at low loadings confers an overall improvement in composite properties, the exact ratios of individual fillers and combined forms remain to be discussed in depth. Finally, potential applications, current challenges and future perspectives for use of these multiphase composites are discussed with regard to their extraordinary capabilities and promising developments in graphene/CNT family-based composite materials. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered nanomaterials, including layered double hydroxides, graphene, montmorillonite, expandable graphite and molybdenum disulfide, as additives to prepare polymer-based flame retardant nanocomposites, have received much interest in the scientific community in recent years. Based on some unique properties of these layered nanomaterials, as well as different flame-retarding mechanisms, various multifunctional nanocomposites can be designed and fabricated. In this paper, first the flame-retarding mechanisms are discussed. Then, the recent progress in polymer-based flame retardant nanocomposites modified by various 2D layered nanomaterials, including the modification methods, are reviewed. The present status and prospective are also discussed. [ABSTRACT FROM AUTHOR]

Drug-loading on magnetic nanoparticles coated with biocompatible polymers are intriguing nanostructures for targeted delivery of anticancer drugs with the application of a magnetic field. In this paper, we report the preparation of SmFeO3 nanoparticles and loading of the anticancer drug 5-fluorouracil on the carrier by forming host-guest complex with β-cyclodextrin. The material and the polymer are characterized using IR and EDX spectroscopic techniques. The nanocarrier formulation shows an enhanced loading and release of the drug. The size and the magnetic properties of the nanoparticles are suitable for cancer drug targeting, i.e., around 50 nm, and the particles show a superparamagnetic behavior. In vitro cytotoxicity studies reveal that the loaded 5-fluorouracil retains its potency and the drug-loaded nanocarrier shows better anticancer activity. [ABSTRACT FROM AUTHOR]

This paper presents the first effort to investigate the effects of uniform and nonuniform prestraining on the mechanical properties of nanostructured multilayers. Thin muscovite sheets were first subjected to a loading-unloading cycle under unidirectional compression and cantilever bending modes that induce uniform and nonuniform prestraining, respectively, and then probed by nanoindentation to characterize their Young’s modulus and hardness. Optical and electron microscopy and X-ray diffraction were also used to uncover prestraining-induced microstructure alterations. Precompression in the c* direction to a stress of 45 MPa induces elastic uniform straining and causes negligible alteration to the microstructure. Such a prestrained specimen possesses unaltered Young’s modulus and hardness. However, the nonuniformly prestrained specimens that were subjected to cantilever bending, even though bending is macroscopically purely elastic, exhibit decreased Young’s modulus and hardness, and such reduction depends on the magnitude of bending strains. The Young’s modulus decreases by up to 41.0%, from 69.5 to 41.0 GPa at 0 to ~ 6% bending strains, respectively, while the maximum hardness reduction is 40.4%. Such distinction induced by different prestraining modes stems from the bending-induced nonuniform straining as well as the muscovite’s unique nanoscale layered structure. Owing to the relatively weaker and reversible electrostatic interlayer bonding, bending-induced strain gradient along the c* direction causes relative interlayer slip and hence bonding switch and, upon unloading, leads to the formation of basal plane corrugation and subsurface blisters. Such structural incoherence and imperfections induced by even elastic bending reduce the Young’s modulus and hardness. These findings shed light on the processing-structure-property relationships for other nanostructured multilayers as well as the origin of variability of elastic modulus of muscovites reported in the literature. [ABSTRACT FROM AUTHOR]

In the present work, novel CuS superstructures composed of intersectional CuS nanoplates (CuS i-nanoplates) and snowflake-like CuS nanoplates (CuS s-nanoplates) were successfully synthesized at a low temperature (80 °C) by a simple chemical precipitation method. It has been found that the as-synthesized CuS superstructures were formed by the growth of CuS i-nanoplates along the direction perpendicular to the basal nanoplate with a thickness of 29.64 ± 3.16 nm and CuS s-nanoplates were prepared with the snowflake-like morphology with a thickness of 16.82 ± 3.62 nm. Subsequently, a new transparent heat insulation coating with CuS superstructures composed of CuS i-nanoplates as NIR shielding agent (coded as H-X coating) was prepared by mixing with acrylic-amino-alkyd baking varnish and coating to ordinary glass substrates. Simultaneously, another transparent heat insulation coating with s-nanoplates (coded as S-X coating) was also synthesized. Optical properties of those coatings were studied as a function of the CuS content by using ultraviolet-visible-near-infrared spectrophotometer. And the H-X coatings were shown to have a higher selective shielding ability for solar light than S-X coatings since the shielding ability of S-X coatings in the region of 1180-2500 nm rapidly weakened with increasing wavelength. The comparative study on the properties of nanomaterials with different morphologies in this paper may provide some new guidance for material design to improve its performance. Moreover, the CuS superstructure-based transparent heat insulation coatings with excellent NIR shielding property have a potential application in energy-saving windows for architectures and vehicles. [ABSTRACT FROM AUTHOR]

The metastable ω phase stabilizes either in hexagonal (P6/mmm) or trigonal (P3¯m1) structures depending upon the extent of collapse of the atomic planes. The stability between these two structures depends on the atomic scale shear mechanism of the ω formation and also on the relative composition of the bcc stabilizer. Detailed interpretation of the bcc → ω phase transformation demands understanding of structure, chemistry and interface of ω phase along with the bcc matrix down to the atomic level. Present paper deals with the structural imaging of partially collapsed ω structure and its lattice correspondence with the bcc phase in a phase-separated V-Ti alloy. High-resolution TEM characterization with the aid of phase-contrast image simulation and atomic structure modeling has been systematically carried out to study the structural aspects of the nanostructured ω. The contrast of the collapsed atoms and the corner atoms are understood through systematic studies of the experimental images and their corresponding column intensities, as seen along simulated exit waves and their phase and amplitude parts along different zone axis. Attempts have also been made to understand the qualitative nature of the electron channeling behavior along the different atomic positions of the ω structure. [ABSTRACT FROM AUTHOR]

In this paper, multiple hydrogen bonding interaction of ureidopyrimidinone (UPM) was employed as the linking bridge for the formation of a novel porphyrin·multi-walled carbon nanotube (MWNT) hybrid, which was then used to fabricate a layer-by-layer (LbL) film composed of porphyrin-UPM·MWNT-UPM. Both in the assembled hybrid and the LbL film, porphyrin was closely attached to the surface of the MWNT under the strong multiple hydrogen bonding interaction, forming the core-shell structure. In addition, strong electronic communication was observed between porphyrin and MWNT. The hydrogen bonding association behavior between porphyrin-UPM and MWNT-UPM was attentively analyzed by UV-Vis spectra, fluorescent spectra and transmission electron microscope experiments. It was found that the hydrogen bonding interactions were crucial for the formation of the supramolecular hybrid and the LbL film as well as the occurrence of interfacial electronic communication. This result indicated that the introduction of strong noncovalent bonding interaction between donor and acceptor is an appropriate way to control the material structure and facilitate the interfacial electronic communication in the hybrids which lay the groundwork for their application in electrochemical sensors or photovoltaic devices. [ABSTRACT FROM AUTHOR]

Melt blowing is an industrial approach for producing microfibrous nonwoven materials utilizing high-speed air to attenuate polymer melt. The melt-blowing air flow field which is widely believed to be turbulence determines the process of fiber formation. In this study, the turbulent air flow field in slot-die melt blowing was experimental measured by hot-wire anemometer. The fluctuations of air velocity and temperature, the mean velocity and mean temperature were measured and analyzed; moreover, the relationship between turbulent air flow field and fiber formation in melt blowing was discussed and predicted. In the last part of this paper, the coupling effect of air temperature and velocity was studied tentatively, results showed that air temperature not only had an enhanced effect on velocity, but contributed to the fluctuation of velocity. This work shows that the fluctuating characteristics of air velocity and temperature have dominant effect on fiber motion and the evenness of fiber diameter. [ABSTRACT FROM AUTHOR]

Transition metal oxide (TMO) nanomaterials possess both novel nanoeffects and excellent semiconductor properties that make them promising materials for electronics and photonics. Great expectations have been placed on TMO nanomaterials to deal with the global challenges in many fields, especially portable equipment and energy issues. In the last decades, extensive research work concentrated on the synthesis, microstructure, and macro-performance of TMO nanomaterials. A comprehensive understanding of both growth mechanism and underlying relationship between microstructure and physical properties can lead to performance enhancements of TMO nanomaterials in electronics and photonics, which in turn enables the fabrication TMO nanostructures based on anticipated design strategies. At present, TMO nanostructures do not satisfactorily meet the technical criteria for direct practical applications in electronics and photonics. In this paper, recent developments in synthesis, characterization, and prominent applications of TMO nanomaterials are reviewed from a structural perspective, which serves as a stepping stone to develop novel nanostructures with superior performances and provides a necessary guidance for transformation of scientific achievements into practical applications. [ABSTRACT FROM AUTHOR]

In this paper, the core/shell Ni-P@Ni-Co composite with micro-/nanostructure, coating Ni-Co on the precursor Ni-P microspheres, has been synthesized successfully via facile two-step hydrothermal method. The chemical composition and microstructure of as-prepared samples were characterized by XRD, EDS, BET, XPS, SEM, and TEM. The results show that the core/shell composite Ni-P@Ni-Co, with a more rough surface and larger specific surface area (74.2 m g) than bare Ni-P, exhibits good charge storage performance (the specific capacitance reaches up to 1221.1 F g at the current density of 1 A g, 1.8 times of Ni-P under the same conditions), and good cycling performance (the retention of specific capacitance is 95.8% after 5000 cycles at 2 A g current density). To further evaluate the practical application property of Ni-P@Ni-Co, an asymmetric supercapacitor (Ni-P@Ni-Co//AC) was assembled, with the Ni-P@Ni-Co and activated carbon (AC) as the positive and negative electrodes, respectively. The electrochemical results reveal that Ni-P@Ni-Co//AC delivers a high energy density of 28.9 Wh kg at a power density of 0.4 kW kg, along with a specific capacitance retention rate of 89.1% and nearly 100% Coulomb efficiency at a current density of 1 A g after 5000 cycles. [ABSTRACT FROM AUTHOR]

Interface contributions as well as size confinement effects need to be taken into account into the description of phase equilibria and phase transformations in nanoscale systems. Here, a modified Gibbsian thermodynamic approach has been suggested to describe the solidification of a nano-sized liquid alloy droplet and the equilibrium states in the two-phase region of the phase diagram. Cu-Ni has been chosen as a model system due to the availability of thermodynamic data. This description shows for the first time the occurrence of solidification loops at the size-dependent temperature-composition phase diagram for the isolated Cu-Ni nano-droplet, showing two-phase equilibrium states for droplet radii of 25 and 40 nm, i.e. well within the size domain of nanoparticles that are, for example, used for applications in additive manufacturing. Furthermore, the current results show quantitatively that these equilibrium loops that are specific for the nano-sized systems do not coincide with the solubility curve. It leads to the new 'solidification loop' concept concerning the phase diagram introduced in the paper. The isolated liquid Cu-Ni nanoscale droplet can actually crystallize along different trajectories, whereas the dominant transition type is comparable to homogeneous nucleation that proceeds from the inner part of the droplet towards the surface: the newly formed phase after initial nucleation is a Ni-rich crystal with a Cu-rich liquid shell. The decrease in the nanoparticle size causes the decrease in the solidification temperature and the temperature width of the phase transition, the increase in the solubility limit and the concentration width of the solidification loop as well as a change in the shape and slope of the equilibrium curves of the two-phase region of the phase diagram. For larger droplets, the size-dependent phase diagram approaches the well-known bulk phase diagram. [ABSTRACT FROM AUTHOR]

To study the impact response of the functionally graded carbon nanotubes reinforced composite (FG-CNTRC) laminates, four types of stacking arrangements were discussed in this paper. The general Kármán type equations, rule of mixture and Hertz contact law were used to formulate the laminate, material and contact behavior, respectively. The effects of different gradient forms, temperature, initial velocity and volume fraction of carbon nanotubes (CNTs) on the impact behavior of the laminates were investigated. The results suggest that the titanium alloy layer has improved the stiffness and strength of the laminates and weakened the influence of the FG-CNTRC. A higher temperature results in a larger center displacement due to the existence of the temperature-dependent materials. In addition, a faster velocity leads to a larger deformation rate of the laminate in the initial stage and also a larger center displacement. [ABSTRACT FROM AUTHOR]

The incorporation of nanomaterials that are biocompatible with different types of biological compounds has allowed the development of a new generation of biosensors applied especially in the biomedical field. In particular, the integration of film-based nanomaterials employed in field-effect devices can be interesting to develop biosensors with enhanced properties. In this paper, we studied the fabrication of sensitive nanofilms combining ZnO nanocrystals and carbon nanotubes (CNTs), prepared by means of the layer-by-layer (LbL) technique, in a capacitive electrolyte-insulator-semiconductor (EIS) structure for detecting glucose and urea. The ZnO nanocrystals were incorporated in a polymeric matrix of poly(allylamine) hydrochloride (PAH), and arranged with multi-walled CNTs in a LbL PAH-ZnO/CNTs film architecture onto EIS chips. The electrochemical characterizations were performed by capacitance-voltage and constant capacitance measurements, while the morphology of the films was characterized by atomic force microscopy. The enzymes glucose oxidase and urease were immobilized on film's surface for detection of glucose and urea, respectively. In order to obtain glucose and urea biosensors with optimized amount of sensitive films, we investigated the ideal number of bilayers for each detection system. The glucose biosensor showed better sensitivity and output signal for an LbL PAH-ZnO/CNTs nanofilm with 10 bilayers. On the other hand, the urea biosensor presented enhanced properties even for the first bilayer, exhibiting high sensitivity and output signal. The presence of the LbL PAH-ZnO/CNTs films led to biosensors with better sensitivity and enhanced response signal, demonstrating that the adequate use of nanostructured films is feasible for proof-of-concept biosensors with improved properties that may be employed for biomedical applications. [ABSTRACT FROM AUTHOR]

Spark plasma sintering (SPS) is a versatile and effective rapid processing technique to sinter nanostructured thermoelectric (TE) materials. This paper presents a combined experimental and modelling investigation of the Peltier effect during SPS processing of TE materials. The Peltier effect is related to the transport of heat by an electric current and produces a temperature gradient. This heat flow manifests itself at the junction between two dissimilar materials at which heat is evolved or absorbed. During SPS processing, the Peltier effect could manifest itself as a significant temperature gradient across the sample. The Peltier effect was found to produce a temperature gradient of 55 °C during the SPS processing of MgSi (ZT = 1.4, 3 mm sample thickness) and 60 °C for MnSi (ZT = 0.4, 3 mm sample thickness). The overall developed experimental and numerical methodology allowed us to confirm the existence of the Peltier effect and to quantify its magnitude. This enabled us to determine a correlation between the SPS process parameters and temperature gradient across the processed TE materials. [ABSTRACT FROM AUTHOR]

In preparation and application of nanomaterials, the dissolution of nanoparticles is usually involved. However, it remains unclear about size dependent the dissolution kinetic parameters of nanoparticles. In this paper, kinetic model for the dissolution of nanoparticles is proposed, and the relations between dissolution kinetic parameters (rate constant, order, apparent activation energy and pre-exponential factor), respectively, and particle sizes were theoretically deduced by applying the transition state theory to the dissolution process, and then the influence regularity and mechanism of particle size on the kinetic parameters were discussed. Experimentally, the dissolution kinetic parameters of nano-CaCO with different particle sizes were determined by conductivity meter, and the quantitative influences of particle size on the dissolution kinetics were obtained. The experimental results are consistent with the theoretical relations. The results show that there are significant effects of the particle sizes of CaCO nanoparticles on dissolution kinetic parameters; with the particle diameter decreasing, the apparent activation energy and the pre-exponential factor correspondingly decrease, while the rate constant and the dissolution order increase sharply. When the diameter of nanoparticle exceeds 20 nm, the logarithm of the dissolution rate constant, the apparent activation energy, and the logarithm of the pre-exponential factor are all linearly related with the reciprocal of particle diameter. Furthermore, the apparent activation, the dissolution order, the pre-exponential factor, and the dissolution rate constant are influenced by the partial molar surface enthalpy, the partial molar surface area, the partial molar surface entropy, and the partial molar surface Gibbs energy, respectively. [ABSTRACT FROM AUTHOR]

Micro/nanotopographical modification of biomaterials plays an essential role in the improvement of implants' cytocompatibility. In this paper, hierarchical micro/nanostructured surface was constructed to improve the titanium alloy cytocompatibility, which combined sandblasting, acid etching, and alkali heat treatment. The surface features were characterized using scanning electron microscope (SEM), laser scanning microscope, X-ray diffraction (XRD), and contact angle goniometer. A series of biological tests were carried out to evaluate cytocompatibility of bio-titanium alloy in vitro, including cell adhesion, counting, proliferation, osteocalcin expression, alkaline phosphatase (ALP) activity, and extracellular matrix mineralization. The results show that bio-titanium alloy with micro/nanostructured surface provided a beneficial interface which could promote the growth of osteoblasts. A uniform nanowire layer with high hydrophilicity was superposed on microstructures. Meanwhile, the biological tests indicate that hierarchical micro/nanostructures with micropits and nanowires could significantly promote osteoblasts' initial adhesion, proliferation, and differentiation. Moreover, the underlying mechanism of interaction between implants and cells was also discussed. This work proposes an effective approach to fabricate micro/nanostructured surface on titanium alloy for cytocompatibility improvement. [ABSTRACT FROM AUTHOR]

One-dimensional nanostructures grown on substrates are favored for photocatalytic reactions because of their large specific surface areas and well-defined transport paths for charge carriers. In the present paper, zinc ferrite nanotube arrays are synthesized on indium-tin-oxide-glass substrates, and their photocatalytic capabilities are evaluated by degrading an aqueous solution of rhodamine B (RhB) under visible light irradiation. The photocatalytic performance of pure zinc ferrite nanotube arrays is unsatisfactory. To improve their photocatalytic abilities, the surfaces of zinc ferrite nanotube arrays are decorated with Au nanoparticles, significantly enhancing their photocatalytic capabilities for RhB degradation. The drastic improvement in the photocatalytic degradation ability is attributed to the effective separation of photogenerated electron-hole pairs in the Au-decorated zinc ferrite hybrid nanostructure, which facilitates the generation of oxidizing free radicals (i.e., O − and OH·) for RhB degradation. [ABSTRACT FROM AUTHOR]

Recent experiments with hexagonal boron nitride ( h-BN) have shown the successful covalent and non-covalent functionalization of these boron nitride nanostructures, especially nanosheets (BNNS). This paper explores the synthesis of several thiophene-based polymers with conjugated pendant groups and their reactions with BNNSs. Specifically, two phenyl carboxylic acid functionalized polythiophene polymers, poly[3-(4-methoxycarbonylphenyl)thiophene] and poly[3-(4-benzoic acid)thiophene], have been prepared and reacted with exfoliated BNNSs. The resulting complexes between the conjugated polythiophene polymers and the BNNS are reported and characterized by their reaggregation stability and by spectroscopic methods. [ABSTRACT FROM AUTHOR]

Recent studies in the field of iron oxide-dendrimer hybrids showed an increased potential of these materials to be used in diagnosis, monitoring, targeting, and therapy of cancer. The aim of this paper is to investigate the nature of interactions between iron oxide nanoparticles and polyamidoamine (PAMAM) dendrimers using computational and experimental techniques, namely molecular dynamics (MD) and electron paramagnetic resonance (EPR). Hybrid nanostructures based on iron oxide and PAMAM dendrimers were prepared in one-step synthesis route, using hydrothermal method at high pressure (40-100 atm). The interaction between dendrimers and iron oxide nanoparticles was predicted at specific temperature, pH, and pressure conditions. The same conditions were applied for hydrothermal synthesis. High-resolution transmission electron microscopy revealed the formation of magnetite (MAG) through hydrothermal reaction at 100 atm, starting only from iron (III) chloride. A possible explanation could be the variation of the fugacity value of oxygen under high-pressure conditions, which leads to diffusion-controlled reaction and to transformation of haematite into MAG. EPR parameter, namely linewidth, was exploited to evaluate the type of interactions from iron oxide-PAMAM hybrids, due to its dependence on spin-spin relaxation time and spin-lattice interactions. As a conclusion, MD indicated the existence of electrostatic interactions between PAMAM and iron oxide. In accordance with in silico results, EPR analysis suggested that MAG is not entrapped in PAMAM structure and the interactions between organic and inorganic components take place at dendrimer's surface. A good agreement between MD simulations and experimental results was observed. [ABSTRACT FROM AUTHOR]

This paper reports the partial replacement of Portland cement (PC) by combination of metakaolin (MK) and nanoclay (NC) in sisal fiber-reinforced cement composites by studying the microstructure, mechanical behavior, and the interfacial properties between fiber and cement matrices. The mechanical properties of cement matrix and natural fiber-reinforced composites are studied using compressive strength development and flexural behavior, respectively. The tensile behavior of the natural fiber was also investigated and analyzed by Weibull distribution model. The characteristics of hydration products were analyzed by scanning electron microscope, X-ray diffraction, and thermogravimetry analysis. Our results show that the combination of MK and NC can improve the hydration of cement more effectively, with better microstructure and enhanced mechanical properties, than mixes without them. The calcium hydroxide (CH) contents of matrixes with 50 wt% combined substitutions, containing 1, 3, and 5 wt% of nanoclay, were 58.12, 60.16, and 64.25 % less than that of PC, respectively. The ettringite phase is also effectively removed due to the substitution of MK and NC, which improve both Al/Ca and Si/Ca ratios of calcium silicate hydrates (C-S-H) due to the high content of SiO and AlO. The interfacial bond between fiber and cement matrix and flexural properties of sisal fiber-reinforced cement composites are also significantly improved. The optimum interface adhesion between sisal fiber and matrix was achieved by replacing cement by 27 % MK and 3 % NC, which increased the bond strength and pull-out energy by 131.46 and 196.35 %, respectively. [ABSTRACT FROM AUTHOR]

Ultrathin MoS sheets and nanostructures are promising materials for electronic and optoelectronic devices as well as chemical catalysts. To expand their potential in applications, a fundamental understanding is needed of the electronic structure and carrier mobility as a function of strain. In this paper, the effect of strain on electronic properties of monolayer MoS is investigated using ab initio simulations based on density functional theory. Our calculations are performed in both infinitely large two-dimensional (2D) sheets and one-dimensional (1D) nanoribbons which are theoretically cut from the sheets with semiconducting $$ [\bar{1}100] $$ (armchair) edges. The 2D crystal is studied under biaxial strain, uniaxial strain, and uniaxial stress conditions, while the 1D nanoribbon is studied under a uniaxial stress condition. Our results suggest that the electronic bandgap of the 2D sheet experiences a direct-indirect transition under both tensile and compressive strains. Its bandgap energy ( E) decreases under tensile strain/stress conditions, while for an in-plane compression, E is initially raised by a small amount and then decreased as the strain varies from 0 to −6 %. On the other hand, E at the semiconducting edges of monolayer MoS nanoribbons is relatively invariant under uniaxial stretches or compressions. The effective masses of electrons at the conduction band minimum (CBM) and holes at the valence band maximum (VBM) are generally decreased as the in-plane extensions or compressions become stronger, but abrupt changes occur when CBM or VBM shifts between different k-points in the first Brillouin zone. [ABSTRACT FROM AUTHOR]

Pure zinc oxide, single-doped zinc oxide as 2 wt% of Lanthanum as (La DZ NPs), 2 wt% of Samarium (Sm DZ NPs), and 2 wt% of Strontium as (Sr DZ NPs), and tri-doped (Sm, La, Sr, T DZ NPs) were synthesized with a hydrothermal method. Additionally, these nanomaterials are used as an effective photocatalytic for the degradation of Reactive Red 43. These nanomaterials' optical, particle size distribution, structural properties, and morphology were analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet (UV) light, photoluminescence (PL), scanning electron microscopy (SEM) and energy-dispersive X-ray (XPS), transmission electron microscopy (TEM), and the point of zero charges (pHpzc). Molecular modeling simulation was calculated using density functional theory (DFT) to confirm some characterization. Moreover, these studies showed the crystal structure parameters changed with doped nanomaterials, and the experimental band gap fit theoretical calculation and demonstrated the reason for the widening of the band gap. An enhancement in the surface area of Sr DZ NPs recorded high value (SBET = 37.43 m2/g) indicated that it can be used as an efficient photocatalyst, where Sr DZ NPs showed the best photodegradation % of Reactive Red 43 dye with 93.43% compared to PZ (72.88%), La DZ NPs (52.54 3%), Sm DZ NPs (31.99%), and La, Sm, Sr T DZ NPs (20.55%). Furthermore, the pseudo-first-order kinetic model better fits the R2 values. Finally, the mechanism of degradation has been related to electronic configuration. In addition, the recyclability showed stability of nanomaterials under UV irradiation. [ABSTRACT FROM AUTHOR]

Two-dimensional porous carbon nanosheets with large surface areas and high heteroatom contents are very appealing for applications in electrochemical energy storage. Herein, we offer a boulevard to prepare nitrogen- and oxygen-codoped carbon nanosheets (NOCNs) with high N, and O contents from a linear Schiff-base polymer (L-SBP), which was synthesized based on a convenient condensation reaction. Subsequently, NOCNs-T was achieved by pyrolysis of L-SBP at different temperatures (T). The derived NOCNs-800 offered a high specific surface area (SSA) of 478.7 m2 g−1 with a pore volume of 0.507 cm3 g−1. When employed as electrode materials for Li-ion batteries (LIBs), the Li-ion storage performance of NOCNs-T was notably improved after the pyrolysis of L-SBP under Ar atmosphere. Compared with NOCNs-700, and NOCNs-900, the as-prepared NOCNs-800 demonstrated a high reversible capacity with outstanding rate performance and cyclic durability. The discharge-specific capacity was maintained at about 380.4 mAh g−1 at 100 mA g−1 after 200 cycles. The excellent energy storage performance can be ascribed to the large SSA, high heteroatom contents, and suitable pores, offering abundant active sites and wettability. [ABSTRACT FROM AUTHOR]

The pathological hallmark of many amyloid diseases is the aggregation and deposition of soluble proteins into toxic insoluble fibrils in various tissues. Without any definite cure for these proteinopathies, researchers have explored small molecules, antibodies, peptides, nanomaterials etc., as potential agents interacting with different conformational species of amyloid-forming proteins. Mainly, amyloid fibrillation inhibitors in the form of cyclic peptides (CPs) (based on amyloid and non-amyloid-forming protein sequences) show remarkable anti-amyloidogenic activity as well as chemical, thermal, and proteolytic stability over their linear counterparts. Furthermore, some 'add-on' attributes include ease of synthesis, amenability for chemical modification, precise and tight binding (high specificity) to target peptides, and biocompatibility. This article highlights the design, synthesis, bioactivity, and mechanistic evaluation of rationally designed CPs inhibitors against amyloid systems. This review also discusses the dual role of nanoparticles as inhibitors of amyloid fibrillation and as carriers for the delivery of therapeutic molecules across the blood–brain barrier. Thus, combining CPs and nanoparticles could represent 'next-generation therapeutics' for amyloid diseases. [ABSTRACT FROM AUTHOR]