Electrochemical dissolution by congruent oxidation of Fe Pd in 1 M HCl solution was strongly controlled by crystallographic orientation. Anodic dissolution was characterized over a wide variety of grain surface plane orientations providing a detailed view of the crystallographic nature of oxidative dissolution and surface facet evolution as a function of grain orientation. Near {100}-oriented grains retained low surface roughness after corrosion and low dissolution rates. Grains with orientation within 2° of {111} were also topographically smooth after dissolution and were nearly as corrosion resistant as {100} grains. Overall dissolution depth depended linearly on crystallographic angle within 40° of {100} and within 10° of {111} planes. Post-corrosion surface faceting and dissolution were substantially increased at grain orientations near {110} and were highest between 10° and 20° from the {111} plane normal. Grains at these crystallographic angles roughened during oxidative dissolution by forming complex semi-periodic topographies. These finely spaced arrays of terraces and ledges likely consisted of combinations of more corrosion resistant low-index planes. Therefore, the overall corrosion depth within a grain possessing an initially irrational crystal orientation was determined by the amount of dissolution required to expose new, slowly dissolving surface facets with low-index orientations. Computations of Fe–Pd alloy surface energies and surface atom coordination as a function of crystal orientation are utilized to help support this explanation.

Epitaxial heterostructures composed of complex oxides have fascinated researchers for over a decade as they offer multiple degrees of freedom to unveil emergent many-body phenomena often unattainable in bulk. Recently, apart from stabilizing such artificial structures along the conventional [001]-direction, tuning the growth direction along unconventional crystallographic axes has been highlighted as a promising route to realize novel quantum many-body phases. Here we illustrate this rapidly developing field of geometrical lattice engineering with the emphasis on a few prototypical examples of the recent experimental efforts to design complex oxide heterostructures along the (111) orientation for quantum phase discovery and potential applications.

A specialized dealloying technique called thermal dealloying was developed over 10 years ago for certain biomedical materials. This method is not widely used for synthesizing nanoporous metals. However, it offers advantages over conventional dealloying processes for fabrication of nanoporous structures, and is highly suitable for refractory metals that may be susceptible to oxidation during chemical/electrochemical dealloying and liquid metal dealloying. In this study, nanoporous structures were successfully fabricated from magnesium-based precursor alloys via sublimation of magnesium at elevated temperature under vacuum conditions. Different refractory metal diffusion rates affect the resulting density and amount of retained magnesium in each nanoporous material.

Electrically conducting substrates have shown much promise as neuronal scaffolds and in other biologic and biomedical applications where a smart and electrically interactive material is needed. Most materials that are inherently conducting are not suitable for biomedical applications and lack biocompatibility or biostability. On the other hand, biologically stable and compatible materials must first be manipulated, modified, and treated in order to impart the necessary electrical conductivity to the material. Here, the authors have investigated the response of PC-12 cells to two types of conducting carbon-based aerogels with different surface roughness. Results show that carbon-based aerogels support cell adhesion, proliferation, and neurite extension. The effects of surface roughness have also been investigated.

The Mn-doped ZrO2/TiO2 nanostructured photocatalysts had been prepared by the simple hydrothermal method. The morphologies and structures of the as-prepared photo-catalyst were characterized by transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and electron paramagnetic resonance. The resultant nanostructured photocatalysts exhibited high photocatalytic activity under ultraviolet (UV) light irradiation, attributing to the improvement of the photo-absorption property and the separation efficiency of photo-generated electrons and holes. The hydroxyl radicals (•OH), superoxide radical (•O2−), and holes (h+) are the main active species in aqueous solution under UV light irradiation.

Applications of polymer thin films include functional coatings, flexible electronics, membranes and energy conversion. The physical properties of polymer films of nanoscale thicknesses typically differ from the bulk, due largely to entropic effects and to enthalpic interactions between the macromolecules and the external interfaces. Studies of the size-dependent physical properties of macromolecules have largely been devoted to linear chain polymers. In this Prospective, we review recent experiments and simulations that describe the structure and fascinating physical properties, from wetting to the glass transition, of star-shaped macromolecules. The properties of these molecules would render them more useful than their linear chain analogs, for some specific applications.

Akin to the natural tissues, soft artificial muscles possess a life cycle limited by aging and degradation phenomena. Here, we propose a rejuvenation method aimed at silicone-ethanol soft composite actuators, in which ethanol escape occurs during prolonged actuation, thus compromising their performance. The rejuvenation is achieved by immersion of the material–actuator in ethanol, allowing its diffusion into the silicone-based material until saturation. Repeatable rejuvenation of a soft robot, based on the soft material–actuator, resulted in retention of up to 100% of its functionality. Thus, we suggest that this method may be used for the rejuvenation of soft artificial muscles and material–actuators.

The paradigm of molecular discovery in the chemical and pharmaceutical industry has followed a repetitive succession of screening and synthesis, involving the analysis of individual molecules that were both natural and produced. This ability to generate and screen libraries of compounds has found an echo in solid-state physics with the demand to explore and produce new materials for testing. In response to this demand, a golden age of materials discovery is being developed, with progress on important areas of both basic science and device applications. The confluence of theoretical and simulation methods, together with the availability of computation resources, has established the “materials genome” approach that is used by a growing number of research groups around the world with the goal of innovating on materials through systematic discovery. In this Prospective, an overview of this group of methodologies in tackling the ever-increasing complexity of computational materials science simulations is provided. Computational simulation is highlighted as a major component of rational design and synthesis of new materials with targeted properties, describing progress on databases and large data treatment. Tools for new materials discovery, including progress on the deployment of new data repositories, the implementation of high-throughput simulation approaches, and the development of artificial intelligence algorithms, are discussed.

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?

The effect of p-type doping at ultra-low concentrations (~10−4–10−5 monomer mol fraction) of the polymer poly(3-hexylthiophene) (P3HT) is studied using charge modulation (CM) spectroscopy. Quantitative analysis of CM spectra of doped P3HT show that dopants induce measurable changes in the P3HT local chain conformation. We find that the dopants reside in both the aggregate and amorphous regions of the polymer, not just in the amorphous regions, as previously assumed. With increased doping, the P3HT intrachain disorder grows, causing the P3HT chains to become more oligomer-like, which we postulate leads to the drop in mobility commonly observed in literature.

We synthesized two types of ZnO nanoparticles (NPs) for comparison, the first NPs were produced using a Zn(Ac)2.2H2O solution in distilled water and the second were produced using a Zn(Ac)2.2H2O solution in an aqueous extract of Mentha (mint). The x-ray diffraction patterns were indexed on the basis of a hexagonal (wurtzite) structure. The samples illustrate the high crystalline quality, and the average crystal sizes of the NPs were calculated to be 50 and 60 nm for GS and NS, respectively. ZnO nanorods were produced for the first time by using green synthesis method.

The demand for high-frequency (HF) and low-cost rectifiers has encouraged many researchers to investigate organic rectifiers. Recently, organic rectifiers with enhanced intrinsic carrier mobility and charge injection efficiency have enabled operating frequencies to reach up to a gigahertz (GHz). The metal/organic and organic/organic interfaces have played a significant role in determining the electrical properties of the organic rectifiers. In this prospective article, we review the structure of organic rectifiers and present the current state-of-the-art to attain their HF performance. We discuss methods for improving their electrical properties using interface engineering and present future prospects for practical use of GHz-operable organic rectifiers.

Thermal conductivity of single-crystal boron-doped diamond (BDD) was studied in comparison with high-quality pure IIa-type diamond in the temperature range from 20 to 400 K. Boron content in BDD was about 1019 cm−3 that is a typical value of p+ substrates used for power device applications. The thermal conductivity of BDD is about 10 times less than that of IIa diamond near 100 K, but above room temperature the difference is <30%. The observed deviation mostly takes place due to acoustic phonon scattering on extended structural defects occurring in synthetic diamond at high boron content.

Multifunctional, complex oxides capable of exhibiting highly-coupled electrical, mechanical, thermal, and magnetic susceptibilities have been pursued to address a range of salient technological challenges. Today, efforts are focused on addressing the pressing needs of a range of applications and identifying, understanding, and controlling materials with the potential for enhanced or novel responses. In this prospective, we highlight important developments in theoretical and computational techniques, materials synthesis, and characterization techniques. We explore how these new approaches could revolutionize our ability to discover, probe, and engineer these materials and provide a context for new arenas where these materials might make an impact.

We have developed a novel, facile, and reproducible synthesis of highly crystalline oleylamine-capped colloidal platinum nanocubes by microwave (MW) heating. Use of MW heating decreases reaction times, eliminates the need for dangerous reagents [e.g., Fe(CO)5], and gives efficient production of monodispersed 8 nm Pt nanocubes [MW-nanoparticles (NPs)]. We also present a study of the optical properties of these NPs, which to our knowledge has not been previously reported. Absorbance spectra of the MW-NPs show a distinct localized surface plasmon resonance band at 213 nm. This observation could be significant for developments in plasmonic photocatalysis and advanced catalytic materials.

Most important advances of the last years in research and development of oxygen ion transport membrane (ITM) materials based on solid or liquid Bi2O3 are briefly given. Special attention is paid to the transport properties of novel NiO/δ-Bi2O3 and In2O3/δ-Bi2O3 ceramic and ZnO/Bi2O3 solid/liquid composites. These composites show promise for use as ITM with the oxygen permeation rate comparable with that of the state-of-the-art membrane materials. The in situ Bi2O3 melt crystallization and grain boundary wetting methods of formation of the gas-tight composites are considered.

There is compelling evidence for the critical role of twin boundaries (TBs) in imparting the extraordinary combination of strength and ductility to nanotwinned metals. Here, we investigate the thermal fluctuations of TBs in face-centered-cubic metals to elucidate the deformation mechanisms governing their kinetic properties using molecular dynamics simulations. Our results show that the TB motion is strongly coupled to shear deformation up to 0.95 homologous temperature. A rather unexpected observation is that coherent TBs do not exhibit any capillarity-induced fluctuations even at high temperatures, in sharp contrast to other high-angle grain boundaries.

The authors propose an alternative route to circumvent the limitation of neutron flux using the recent deep learning super-resolution technique. The feasibility of accelerating data collection has been demonstrated by using small-angle neutron scattering (SANS) data collected from the EQ-SANS instrument at Spallation Neutron Source (SNS). Data collection time can be reduced by increasing the size of binning of the detector pixels at the sacrifice of resolution. High-resolution scattering data is then reconstructed by using a deep learning-based super-resolution method. This will allow users to make critical decisions at a much earlier stage of data collection, which can accelerate the overall experimental workflow.

In this study, an injectable bone substitute (IBS) was produced by mixing a liquid and powder phase. The liquid phase consisted of 8 wt% methylcellulose (MC), 2.5% gelatin, and different amounts of graphene oxide (GO). The powder phase was composed of tetracalcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD), and calcium sulfate dihydrate (CSD). The results showed that 1 and 1.5 wt% GO added IBS samples showed higher stability, injectability, rheological properties, and biocompatibility than the other GO added IBS samples. GO addition significantly decreased the setting time, but it did not significantly affect the compressive strength of the samples.

Harnessing the properties of imidazolium species, antimicrobial activity against Gram-negative and Gram-positive bacteria was attained by binary-grafting 2-hydroxyethyl methacrylate (HEMA) or N-isopropylacrylamide, followed by N-vinylimidazole onto polypropylene (PP) monofilaments (sutures) using 60Co γ-rays. Ulterior functionalization with methyl iodide was carried out to endow brushes with antimicrobial activity on the PP surface. The PP-grafted sutures were characterized by means of Fourier-transform infrared spectroscopy attenuated total reflection, scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analysis, and regarding the mechanical properties and the responsiveness to pH and temperature. Tests were performed on Escherichia coli and Staphylococcus aureus achieving large inhibition zones.