To save this undefined to your undefined account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your undefined account.
Find out more about saving content to .
To save this article to your Kindle, first ensure email@example.com is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Besides graphite and diamond, the solid allotropes of carbon in sp2 and sp3 hybridization, the possible existence of a third allotrope based on the sp-carbon linear chain, the carbyne, has stimulated researchers for a long time. The advent of fullerenes, nanotubes, and graphene has opened new opportunities and nurtured the interest in novel carbon allotropes, including linear structures. The efforts made in this direction produced a number of interesting sp-hybridized carbon molecules and nanostructures in the form of carbon-atom wires. Here we discuss some of the new perspectives opened by the recent advancements in the research on sp-carbon systems.
Evolving from the oblique-angle deposition method used industrially for the deposition of thin films, the conformal-evaporated-film-by-rotation (CEFR) technique has been successfully applied to replicate surfaces of biologic origin. The CEFR technique is the first step of the Nano4Bio technique, an industrially scalable bioreplication process, the other three steps being electroforming, plasma ashing, and either stamping or casting. These techniques have found optical applications in diverse fields, including forensic science, pest control, and light sources.
The helium ion microscope (HeIM) holds immense promise for nano-engineering and imaging with scope for in-situ chemical analysis. Here we will examine the potential of secondary electron hyperspectral imaging (SEHI) as a new route to exploring chemical variations in both two and three dimensions. We present a range of early applications in the context of image interpretation in wider materials science and process control in ion beam-based nano-engineering. Necessary steps for SEHI in the HeIM to evolve into a reliable technique which can be fully embedded into nano-engineering workflows are considered.
Properly driving protein interactions with solid surfaces play a very important role in many natural processes, stimulating a great interest for the design of new biomaterials and medical devices. Despite the progress in this field, many further upgrades have to be achieved to better exploit the protein driving, in terms of control of amounts and conformation of the adsorbing proteins. In this paper, new biocompatible amino acid–calixcrown-5 bilayers were built as nano-templating surfaces, hosting a controlled number of anchoring sites, able to immobilize proteins in well-defined quantity, and the evaluated footprint data support the idea of oriented protein on analyzed substrates. The efficiency of the setup was tested for the particular case of antibacterial lysozyme adsorption on biocompatible surfaces.
Atomic clusters attached to a low-dimensional system, called Fano defects, produce rich wave interferences. In this work, we analytically found an enhanced thermoelectric figure-of-merit (ZT) in periodic atomic chains with Fano defects, compared with those without such defects. We further study self-assembled DNA-like systems with periodic and quasiperiodically placed Fano defects by using a real-space renormalization method developed for the Kubo–Greenwood formula, in which tight-binding and Born models are respectively used for the electric and lattice thermal conductivities. The results reveal that the quasiperiodicity could be another ZT-improving factor, whose long-range disorder inhibits low-frequency acoustic phonons insensitive to local defects.
The fire-retardant and water-repellent bio-structural panels (BISPs) were successfully developed using cellulose nanofibrils, corn starch, boric acid, and n-dodecenyl succinic anhydride with adhesive-free character. Its performance properties were evaluated and compared with other well-known products on the market. The BISP's density (0.1 g/cm3) and permeance value [41.81 g/day/m2 with 5.76% coefficient of variation (CV)] were found higher than compared competitor products. The BISPs' contact angle was found 132.13° (1.59% CV) for BISP. The BISP was the only fire-retardant product, and the only one developed almost no smoke 2.20%.
In this study, we performed computational simulations to extend the behavior knowledge over molecular systems composed by amylose oligomers, three fatty acids often found in Brazilian vegetable oils, water solvent, and montmorillonite. The focus is directed to the molecular movement and to intra and intermolecular interactions, each simulation step being compared with the literature's experimental profile. The calculations were mostly performed by Molecular Mechanics and Dynamics methods. The excellent agreement and complementarities with the literature results indicate, once again, the important contribution offered by the computational simulations to the design of new polymer–clay nanocomposites with biopolymers.
Millions of micro electro mechanical system sensors are fabricated each year using an ultra-clean process that allows for a vacuum-encapsulated cavity. These devices have a multi-layer structure that contains hidden layers with highly doped silicon, which makes common imaging techniques ineffective. Thus, examining device features post-fabrication, and testing, is a significant challenge. Here, we use a combination of micro- and nano-scale x-ray computed tomography to study device features and assess failure mechanisms in such devices without destroying the ultra-clean cavity. This provides a unique opportunity to examine surfaces and trace failure mechanisms to specific steps in the fabrication process.
Significant progress in nanoscience was achieved through the development of methods and instruments to better comprehend nanoscale properties. We present here a methodology and automated setup to measure layer-by-layer films capacitance in the air immediately after polyelectrolytes adsorption. It presents high accuracy (~0.01 pF) to check the capacitance stabilization during spontaneous drying process in the air, with sensitivity to show electrical signal alternation accordingly to the outermost polyelectrolyte layer. Besides, a linear trend in capacitance was observed similar to UV–vis measurements. This method allows analyzing films electrical properties, affording better choice of materials, thickness, and molecular architecture.
Perovskite materials are sensitive to environmental conditions. Here we report the synthesis and characterization of a hydrophobic alkylammonium lead(II) iodide perovskite with enhanced stability in water. Water stability was achieved by growing a shell of 4-[(N-3-butyne)carboxyamido]anilinium lead(II) iodide over methylammonium lead(II) iodide. As a proof of concept, the water-splitting reaction was performed using our new material coated on TiO2, and a 7-fold increase in applied bias photon-to-current efficiency was observed as compared with standard p25-TiO2. Such simple and versatile chemical modification to induce high water stability is useful toward exploring new applications for the perovskite materials.
A novel, alloy-agnostic, nanofunctionalization process has been utilized to produce metal matrix composites (MMCs) via additive manufacturing, providing new geometric freedom for MMC design. MMCs were produced with the addition of tungsten carbide nanoparticles to commercially available AlSi10Mg alloy powder. Tungsten carbide was chosen due to the potential for coherent crystallographic phases that were identified utilizing a lattice-matching approach to promote wetting and increase dislocation interactions. Structures were produced with evenly distributed strengthening phases leading to tensile strengths >385 MPa and a 50% decrease in wear rate over the commercially available AlSi10Mg alloy at only 1 vol% loading of tungsten carbide.
Nanotechnology has been considered as a promising strategy for diagnosis and treatment of various diseases. However, the stability and circulation times of the conventional nano-carriers, such as liposomes and micelles, are still unsatisfied. Perfluorocarbons (PFCs) are biologic inert synthetic materials, which are highly hydrophobic and have a tendency to self-aggregation. Additionally, PFCs themselves can act as 19F magnetic resonance imaging agents and oxygen carriers. Thus, the construction of the fluorinated carriers will not only improve the stability of the carriers, but also endow them with additional functions. Here we review the recent advances of PFC-based nanosystems for diagnosis and treatment of diseases.
The use of zinc nitride (Zn3N2) films as a transparent electrode in various electronic devices has attracted much attention owing to its high-carrier mobility. In this study, we investigate the influence of the sputtering process on structural, optical, and electrical properties of a Zn3N2 film deposited by reactive magnetron sputtering. The reactivity of nitrogen species can be improved by changing the type of sputtering gas. Compared with Ar or Ne sputtering gas, polycrystalline Zn3N2 films deposited using He sputtering gas have a larger grain size. The optical band gap of the Zn3N2 films varied from ~1.2 to 1.5 eV depending on the N2 flow ratio and type of sputtering gas. The maximum mobility was 91.1 cm2/Vs when the Zn3N2 film was deposited using Ar sputtering gas with an N2 flow ratio of 40%. The carrier density of Zn3N2 films deposited using Ar sputtering gas was notably higher than those deposited using Ne or He sputtering gas, and more oxygen atoms are considered to substitute into nitrogen sites, where oxygen is considered to be from the residual water vapor in the sputtering chamber.
Diatoms are unicellular, eukaryotic microalgae inhabiting nearly all aquatic habitats. They are famous for their micro- and nanopatterned silica-based cell walls, which are envisioned for various technologic purposes. Within this review article, we summarize recent in vivo modifications of diatom biosilica with respect to the following questions: (i) Which metals are taken up by diatoms and eventually processed into nanoparticles (NPs)? (ii) Are these NPs toxic for the diatoms and––if so––what factors influence toxicity? (iii) What is the mechanism underlying NP synthesis and subsequent metabolism? (iv) How can the obtained materials be useful for materials science?
In this paper, we reviewed recent research in the field of capillary suspensions and highlight a variety of applications in the field of smart materials. Capillary suspensions are liquid–liquid–solid ternary systems where only one liquid is present in a few percent and induces a strong, capillary-induced particle network. These suspensions have a large potential for exploitation, particularly in the production of porous materials since the paste itself and the properties of the final material can be adapted. We also discussed the rheological properties of the suspension and network structure to highlight the various ways these systems can be tuned.
Focused electron beam-induced deposition (FEBID) is capable of producing metal-containing nanostructures with lateral resolution on the sub-nanometer scale. Practical application of this nanofabrication technique has been hindered by ligand-derived contamination from precursors developed for thermal deposition methods. Mechanistic insight into FEBID through surface science studies and gas-phase electron–molecule interactions has begun to enable the design of custom FEBID precursors. These studies have shown that precursors designed to decompose under electron irradiation can produce high-purity FEBID deposits. Herein, we highlight the progress in FEBID precursor development with several examples that incorporate this mechanism-based design approach.
Multiscale modeling and simulation techniques are transforming the way we can address questions concerning design, characterization, and optimization of novel materials. This transformation is enabled by advanced computational models that incorporate realistic geometries of porous media and serve as tools to predict flow and transport phenomena. Recent developments in mesoscopic and pore-scale modeling include workflows that combine experimental information and direct modeling into an integrated multiscale approach. This review surveys the progress, challenges, and future directions in predictive modeling and simulation of multiphysics phenomena in porous media.
Metal–air batteries promise higher energy densities than state-of-the-art Li-ion batteries and have, therefore, received significant research attention lately. The most distinguishing feature of this technology is that it takes advantage of reversible conversion reactions of O2 or other air components (such as N2 or CO2) at the cathode. To promote these reactions, catalysts are often needed. A large number of materials have been studied for this purpose. In the present paper, we discuss the roles played by catalysts in metal–air battery systems. In particular, we choose to focus the discussions on the Li–O2 batteries as they are most intensely studied in the literature. Within this context, catalysts are often shown effective to facilitate the oxygen (O2) reduction reactions and/or O2 evolution reactions. The overall cell performance as measured by the round-trip efficiencies and charge/discharge rates can be significantly improved by the incorporation of catalysts. However, the presence of catalysts is also found to complicate the chemical reactions as they often exhibit activities toward parasitic chemical reactions such as electrolyte and electrode decompositions. The issue is especially acute in aprotic Li–O2 batteries, where organic electrolytes and reactive O2 species are mixed. In addition to heterogeneous catalysts, we also discuss the roles played by homogeneous catalysts as redox mediators, which are effective to promote redox reactions that are critical to energy storage applications.
The goal of this study is to examine whether participation in high school research apprenticeships increases pursuit of degrees and careers in science, and to explore other apprenticeship benefits. Students who participated in a research apprenticeship were surveyed about its influence on their undergraduate, graduate, and professional decisions. A control group who attended the same high schools, had similar grade point averages, and graduated with the apprenticeship participants was also surveyed. It was found that a significantly higher fraction of the apprenticeship group majored in Science, Math, Engineering, and Technology (STEM) fields, pursued careers in STEM disciplines, and found the experience to strategically influence their job performance.
Porphyrins are photosensitisers used in photodynamic therapy (PDT) due to their tumor localization and in situ singlet oxygen generation. However, their limited absorption, insolubility, and aggregation in an aqueous medium limited their effective application in PDT. To overcome these limitations, we herein, report a large-scale aqueous synthesis of CuInS2/ZnS ternary quantum dots, and its conjugation to 5, 10, 15, 20-meso(4-hydroxyphenyl) porphyrin. The singlet oxygen generation of this highly aqueous soluble novel conjugate shows its potential for PDT applications.