Continuum modeling approaches are well established in materials science and engineering of metals. They enable the quantitative investigation of diverse questions related to the improved understanding of mechanics and microstructure evolution of various material classes. Applicable to time and length scales relevant in manufacturing and service, continuum modeling approaches are widely used to study engineering-related phenomena such as recrystallization, strain localization, fracture initiation, and phase transformations. However, focusing on individual physical aspects hampers the wider routine use of continuum modeling tools for many engineering applications. With the advent of multi-physics modeling tools developed with the help of and parametrized by (sub-)micrometer-scale simulations and experiments, a huge variety of applications such as hot rolling, bake-hardening, and case-hardening comes within reach for full-field integrated computational materials engineering. Moreover, the integration of experimentally characterized microstructures and the use of user friendly simulation and evaluation tools render powerful modeling approaches feasible for a broad materials science user community. The state of the art and future trends of mechanical, thermodynamic, and kinetic continuum modeling of metallic materials at the grain scale are outlined in this prospective article.

Multiferroic nanostructures have been attracting tremendous attention not only for novel phenomena associated with fundamental physics, but also due to exciting application potentials in future nanoelectronic devices. In this mini-review, we first introduce several fabrication techniques recently developed for single phase and composite multiferroic nanostructures. Then, the topologic vortex domain structures in various ferroic nanostructures, which may bring about additional fundamental discoveries and applications in ultrahigh density recording, are discussed. Particular attention is paid to magnetoelectric effects in multiferroic nanodots, including room temperature electric field induced magnetic domain switching. Finally, existing challenges and new directions, e.g., cross-couplings among multiple functionalities, are prospected. We genuinely hope that this mini-review will arouse the readers' interest in this fascinating field.

Lithium (Li)-ion battery cathode materials are typically coated to improve cycling performance, using aqueous-based coating techniques that require filtering, drying, and even sintering of the final product. Here, spherical LiNi0.6Mn0.2Co0.2O2 particles were coated with nano-Al2O3 using the dry mechanofusion method. This method produced a durable, non-porous Al2O3 coating that is retained during slurry making. Mechanofusion coatings significantly improved Li-ion battery cathode cycling at high voltages, enabling high energy densities, while offering inexpensive, scalable, and environmentally friendly solvent-free synthesis. This opens up new possibilities, since, not being limited by synthesis chemistry, mechanofusion can in principle be used to apply any coating material.

Four different vanadium oxide phases [α-vanadium pentoxide (V2O5), β-V2O5, bronze-type vanadium dioxide [VO2(B)], and rutile-type VO2 [VO2(R)])] are investigated from first principles as potential electrode materials for potassium (K) ion batteries. Specifically, insertion energetics and diffusion barriers are computed. These phases are known as promising cathode materials for other types of metal ion batteries. Our results show that the metastable β-V2O5 provides the lowest (strongest) insertion energies for K and the lowest diffusion barriers compared with orthorhombic α-V2O5, VO2(B), and VO2(R). While three of these phases show energetically favorable potassiation and relatively small diffusion barriers, VO2(R) is predicted to be incapable of electrochemical K incorporation.

THz-range dielectric spectroscopy and first-principle-based effective-Hamiltonian molecular dynamics simulations were used to elucidate the dielectric response in the paraelectric phase of (Ba, Sr)TiO3 solid solutions. Our analysis suggests a crossover between two regimes: a higher-temperature regime governed by the soft mode only versus a lower-temperature regime exhibiting a coupled soft mode/central mode dynamics. Interestingly, a single model can be used to adjust the THz dielectric response in the entire range of the paraelectric phase. The central peak cannot be discerned anymore in the dielectric spectra when the rate of underlying thermally activated processes exceeds certain characteristic frequency of the system.

In this work, we showcased a visible-light-assisted reduction of graphene oxide (GO) using N-doped TiO2 photocatalysts. Bench scale capacitive deionization (CDI) experiments determine the optimum working voltage for TiO2–reduced graphene oxide (RGO) nanocomposites as CDI electrodes at 1.8 V. Furthermore, the coupled TiO2 nanoparticles within the as-prepared composite also exhibited photocatalytic ability by removing the humic acid model pollutant. This property is expected to be beneficial as it could relieve the degree of fouling on the electrosorptive surface caused by dissolved organic compounds. In the end, we have demonstrated their potential as a viable desalination water treatment technology in a pilot scale CDI unit.

Shape memory ceramics show potential for energy damping and actuation applications. In particular, small-scale structures of zirconia-based ceramics demonstrate significantly enhanced shape memory and superelastic properties compared with their bulk counterparts, mainly because an oligocrystalline or single-crystal microscale structure reduces mismatch stresses amongst grains. In this Prospective article, we review recent experiments that explore the shape memory properties of small-scale zirconia-based ceramics, including the effects of composition, sample and grain size, and cyclic loading. These factors are reviewed with an eye toward rendering shape memory ceramics more useful in future applications.

Beta-gallium oxide (β-Ga2O3) is of increasing interest to the optoelectronic community for transparent conductor and power electronic applications. Considerable variability exists in the literature on the growth and doping of Ga2O3 films, especially as a function of growth approach, temperature, and oxygen partial pressure. Here pulsed laser deposition (PLD) was used to grow high-quality β-Ga2O3 films on (0001) sapphire and (−201) Ga2O3 single crystals and to explore the growth, stability, and dopability of these films as function of temperature and oxygen partial pressure. There is a strong temperature dependence to the phase formation, morphology, and electronic properties of β-Ga2O3 from 350 to 550 °C.

From being an unfavorable consequence to finding itself as the intended imaginary part of a non-Hermitian system, loss has truly emerged as more of a friend than a foe in the context of acoustic metasurfaces. With the promising features of sub-wavelength geometries and the rapid advances in manufacturing techniques that can enable their realization, loss becomes a central topic of discussion. Further, the capability of introducing and tailoring loss allows it to serve as a new degree of freedom in passive wavefront shaping devices. In this review, the authors look back at the recent progress in the field of lossy acoustic metasurfaces. The background behind loss in deep sub-wavelength geometries and the instinctive responses to treat them and exploit them are overviewed, followed by more recent works that embrace and tailor their behavior for unconventional applications. The forthcoming years for acoustic metasurfaces thus hold several promising avenues for exploration, with loss as the protagonist.

The finite element simulations show that non-equibiaxial residual stresses (RS) can shift the load–depth curve from the unstressed curve and cause elliptical remnant indentation in spherical indentation. Thus the relative load change between stressed and unstressed samples and the asymmetry of elliptical remnant indentation were employed as characteristic parameters to evaluate the magnitude and directionality of RS. Through theoretical and numerical analysis, the effects of RS on indentation load and remnant impression as well as the affect mechanism were systematically discussed. Finally, two equations which could provide foundations for establishing spherical indentation method to evaluate non-equibiaxial RS were obtained.

The S-doped BiOBr composite microspheres were successfully prepared through one-pot solvothermal method. The as-prepared samples exhibit higher photocatalytic activity for the degradation of Rhodamine B and phenol under visible light irradiation, attributed to the improvement of the photo-absorption property and the narrow band gap due to the dopants of S element. The higher efficiency for photodegradation of organic pollutant endows this material with a bright perspective in purification of waste water under visible-light irradiation.

Biologic neural networks are immersed in common electrolyte environment, and homeoplasticity or global factors of this environment are forcing specific normalization functions that regulate the overall network behavior. In this work, a common electrolyte is used to gate a grid of organic electrochemical devices. The electrolyte functions as a global parameter that controls collectively the device grid. Statistical analysis of the grid and the subsequent definition of global metrics reveal that the grid behaves similarly to a single device. This global control modulates the gain of the device grid, a phenomenon analog to multiplicative scaling in biologic networks. This work demonstrates the potential use of electrolytes as homeostatic media in neuromorphic device architectures.

This paper discusses the unique patterns evolved through phase separation of a bulk liquid crystal (LC) from the self-assembly of lysozyme induced by evaporation of de-ionized water only. Each domain shows a central dark region surrounded by bright regions (randomly oriented LC droplets). The birefringence intensity reveals three regimes (a slow increase, rapid rise, then saturation) not seen without LC droplets. The textural study exhibits a simple exponential behavior that changes as a function of LC concentration. Furthermore, in the presence of LC, the crack patterns are found to be different near the drop edge than those in the central region.

There has been increasing interest in so-called phononic materials, which can support surface modes known as surface phonon polaritons, consisting of electromagnetic waves coupled to lattice vibrations at the surface of a polar material. While such excitations have a variety of desirable features, they are limited to the spectral range between a material's longitudinal and transverse optical phonon frequencies. In this work, we demonstrate that for materials whose free-carrier concentrations can be controlled, hybrid plasmonic/phononic modes can be supported across a range of frequencies including those generally forbidden by purely phononic materials.

The inefficiencies of the current pipeline from discovery to clinical approval of drugs demand a surrogate method to indicate adverse drug reactions, e.g. liver damage. Organ-on-chip (OOC) models would be an ideal, rapid, and human-specific alternate, which would render animal testing obsolete. The ground-breaking ability of OOCs and Multi-OOC constructs is the accurate simulation of the in vivo conditions of human organs leading to precise drug screens for cytotoxicity and/or drug efficacy at a faster pace and lesser cost. Here we discuss the innovation, architecture, and the progress of OOCs towards human body-on-a-chip.

Protein-based materials are a powerful instrument for a new generation of biological materials, with many chemical and mechanical capabilities. Through the manipulation of DNA, researchers can design proteins at the molecular level, engineering a vast array of structural building blocks. However, our capability to rationally design and predict the properties of such materials is limited by the vastness of possible sequence space. Directed evolution has emerged as a powerful tool to improve biological systems through mutation and selection, presenting another avenue to produce novel protein materials. In this prospective review, we discuss the application of directed evolution for protein materials, reviewing current examples and developments that could facilitate the evolution of protein for material applications.

Osteoporosis is a skeletal disease characterized by bone loss and bone microarchitectural deterioration. The combination of smart materials and stem cells represents a new therapeutic approach. In the present study, highly porous scaffolds are prepared by combining the conducting polymer PEDOT:PSS with collagen type I, the most abundant protein in bone. The inclusion of collagen proves to be an effective way to modulate their mechanical properties and it induces an increase in scaffolds’ electrochemical impedance. The biomimetic scaffolds support neural crest-derived stem cell osteogenic differentiation, with no need for scaffold pre-conditioning contrarily to other reports.

In this work, we developed a convenient way to immobilize silver nanoparticles on the aminated polyacrylonitrile (PAN) nanofibrous mats by combing the electrospinning technology from complex-containing polymer solution, amination of PAN nanofibrous and electroless plating technique. The resultant composite nanaofibrous mats had been characterized by scanning electron microscopy, energy-dispersive spectrometer, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectra analysis. The catalytic activity and stability of these resultant composite nanofibrous mats for the catalytic reactions, including reduction of 4-nitrophenol to form 4-aminophenol, and selective oxidation of benzyl alcohol, were investigated. The resultant nanofibrous mats exhibited high-efficiency, convenient separation, recovery, and cyclic utilization properties.

Starting from polydisperse diatomaceous earth (DE), we proposed an efficient separation method for obtaining different morphologies of biosilica from diatoms. DE is a very low-cost source of silica containing all the differently nanostructured elements. By a glucose gradient/dialysis, three types of biosilica morphologies were achieved: rods, valves, and clusters. We fully characterized the diatom fractions and we used them to produce fluorescent biosilica platforms (“tabs”). These supports exhibited good resistance in water, ethanol, and soft scraping. A preliminary biologic application by testing Saos-2 proliferation was also performed to check osteoblasts-like cells biologic attitude for this scaffolds with tunable nanostructure.

Axial compression was conducted on micro-pillars, in which polycrystalline Cu thin films were sandwiched between CrN and Si. Plastic flow of Cu was achieved, when the Cu films are inclined either at 90° or 45° with respect to the pillar axis. The texture of Cu films was altered by changing the template on which film growth occurred. The Cu microstructure was further altered by post-deposition annealing. The flow stress shows little dependence on the film texture in the as-deposited state. However, annealing influences the flow stress of confined Cu films significantly. The implications on strain gradient plasticity models are discussed.