Order and porosity of block copolymer membranes have been controlled by solution thermodynamics, self-assembly, and macrophase separation. We have demonstrated how the film manufacture with long-range order can be up-scaled with the use of conventional membrane production technology.

The indole molecularly imprinted polymer (indole-MIP) was synthesized by atom transfer radical emulsion polymerization (ATREP). The novel adsorbent was used to adsorb indole from fuel oil. The indole-MIP had a high selectivity to indole, and the mass transfer limitations were overcome. The property and morphology of indole-MIP were described by a series of characterization methods. A great specific area and more pores of indole-MIP were shown. The static adsorption experiments display that equilibrium adsorption capacity of indole-MIP was 34.488 mg/g. The adsorption process was spontaneous by thermodynamic analysis, and a dense mass of indole was adsorbed onto indole-MIP at a proper low temperature (298 K). Pseudo-second-order kinetic model was more fitted with experimental data. Both Langmuir and Freundlich isotherm models were obeyed by adsorption isotherm test. The selective and competitive performances of indole-MIP were favorable, and the regeneration capacity was appreciable.

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.

In this study, nanocrystalline ZrN films were successfully deposited onto AZ91 alloy using an ion beam sputtering method at substrate temperatures of 373–673 K. Strain and adhesion were calculated using the classic Williamson–Hall and indentation cracking methods, respectively. Microstructure and crystalline properties were evaluated using scanning electron microscopy and x-ray diffraction. XRD results showed that the crystallographic properties of the films were strongly dependent upon substrate temperature. An increase in temperature increased adhesion of the film to the AZ91 alloy and decreased film microstrain. The corrosion behavior of ZrN/AZ91 samples in Ringer's solution was studied to evaluate corrosion potential and corrosion current density. Potentiodynamic corrosion tests showed that all ZrN-coated samples had a corrosion resistance superior to the blank substrate, mainly at 400 °C. A correlation was also established between vacancy defects in the film and corrosion behavior.

A Grade 4 titanium was processed by equal-channel angular pressing (ECAP)–Conform and drawing to produce an ultrafine grain (UFG) size of ~180 nm. Some samples were tested in this condition (UFG-1) and others were annealed for 1 h at 623 K (UFG-2). The grain boundaries are in a non-equilibrium condition after processing, but the annealing equilibrates the boundaries without any increase in grain size. This leads to significant differences in the mechanical behavior of UFG-1 and UFG-2 when they are tested at 293 and 623 K.

Epitaxial graphene of uniform thickness prepared on SiC is of great interest for various applications. On the Si-face, large area uniformity has been achieved, and there is a general consensus about the graphene properties. A similar uniformity has yet not been demonstrated on the C-face where the graphene has been claimed to be fundamentally different. A rotational disorder between adjacent graphene layers has been reported and suggested to explain why multilayer C-face graphene show the π-band characteristic of monolayer graphene. Utilizing low energy electron microscopy, x-ray photoelectron electron microscopy, low energy electron diffraction, and photoelectron spectroscopy, we investigated the properties of C-face graphene prepared by sublimation growth. We observe the formation of micrometer-sized crystallographic grains of multilayer graphene and no rotational disorder between adjacent layers within a grain. Adjacent grains are in general found to have different azimuthal orientations. Effects on C-face graphene by hydrogen treatment and Na exposure were also investigated and are reported. Why multilayer C-face graphene exhibits single layer electronic properties is still a puzzle, however.

Homogenous strontium titanate (SrTiO3) nanofibers were prepared via the electrospinning of precursor solutions containing both strontium and titanium salts. Photocatalytic activities of these SrTiO3 nanofibers for hydrogen generation from water were examined and compared to that of SrTiO3 nanoparticles. The nanofibers calcined at 700 °C showed the highest photocatalytic activity of 167 μmol/h/g among the SrTiO3 samples tested. The high activity was attributed to the ideal stoichiometric ratio of Ti/Sr, small crystallite size, high crystallinity, mesoporous structure, large surface area, and appropriate energy gap. These were confirmed through field emission scanning electron microscopic with energy dispersive spectroscopic observations, x-ray diffraction patterns, N2 gas absorption–desorption isotherm measurements, photoelectron yield spectroscopy in air, and UV-visible spectrophotometry.

This paper describes the mechanical properties under nanoindentation of a new glassy alloy with a nominal composition of Ni60Nb37B3, in the form of melt-spun ribbons and 1-mm-thick copper mold-cast sheets. The alloy composition was designed based on the synergy between the topological instability criterion and the difference in electronegativity among the elements. X-ray diffraction and scanning electron microscopy analyses confirmed that both ribbon and sheet samples possess totally amorphous structures with relatively high thermal stability (supercooled liquid region of about 60 K), as evaluated by differential scanning calorimetry (DSC). Nanoindentation tests revealed that the hardness of this alloy, about 15 GPa, is among the highest reported for metallic glasses. The elastic modulus of the cast sheet is higher and its hardness is similar to that of the ribbon. This correlates well with the different amounts of frozen-in free volume in both types of samples detected by DSC.

A simple stochastic model is developed to determine the pop-in load and maximum shear stress at pop-in in nanoindentation experiments conducted with spherical indenters that accounts for recent experimental observations of a dependence of these parameters on the indenter radius. The model incorporates two separate mechanisms: pop-in due to nucleation of dislocations in dislocation-free regions and pop-in by activation of preexisting dislocations. Two different types of randomness are used to model the stochastic behavior, which include randomness in the spatial location of the dislocations beneath the indenter and randomness in the orientation of the dislocations, i.e., randomness in the stress needed to activate them. In addition to correctly predicting the experimentally observed average maximum shear stress at pop-in, the model also correctly describes the scatter in pop-in loads and how it varies with indenter radius. Monte Carlo simulations are used to validate the model and visualize the scatter expected for a limited number of tests.

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.

Deformation mechanisms of a ZrTiAlV alloy with two ductile phases including a hexagonal close-packed (hcp) structure phase were investigated. A ZrTiAlV alloy was prepared via smelting, breakdown, forging, and suitable heat treatments. X-ray diffraction results show that the proposed ZrTiAlV alloy has two ductile phase structures, namely, hcp structure α-phase and bcc (body-centered cubic) structure β-phase. Scanning electron microscopy (SEM) results show that the plastic deformation of the examined ZrTiAlV alloy starts from the α-phase. Transmission electron microscopy (TEM) analysis shows that only dislocation slips can be found near fractured areas, and the main slip plane in the α-phase is the (0001) lattice plane. Both of the SEM and TEM results show the inexistence of deformation twin in the examined ZrTiAlV alloy including a hcp structure α-phase. Reasons for the abnormal deformation behavior of the hcp structure α-phase are also discussed.

The microstructures of the cast Mg–3Al–1Zn–xCe (x = 0, 0.2, 0.4, 0.8, and 1.2 wt%) alloys produced by twin-roll casting were observed to reveal the effect of cerium (Ce) on the Mg–3Al–1Zn (AZ31) alloy. Transmission electron microscopy (TEM) image of Al4Ce particles at the centers of grains was observed, and the crystallographic calculations between Al4Ce and α-Mg were examined on the basis of the edge-to-edge matching model. The results indicated that the addition of Ce effectively reduces the grain size of the cast AZ31 alloy produced by twin-roll casting. The finest grains with an average grain size of 55 μm are achieved at 0.4 wt% addition of Ce. TEM observation and good crystallographic matching between Al4Ce and α-Mg suggest that promotion of heterogeneous nucleation of α-Mg on Al4Ce particles formed in the melt is responsible for the grain refinement when adding Ce to the cast AZ31 alloy.

The structural properties, the formation enthalpies, and the mechanical properties of Co–Al compounds (CoAl, CoAl3, Co3Al, Co2Al5, Co2Al9, and Co4Al13) are studied by using Chen's lattice inversion embedded-atom method. The potential is transferable and therefore does well for studying different Co–Al compounds. The calculated lattice parameters and cohesive energies are consistent with the experimental and theoretical results. The formation enthalpies of all the Co–Al compounds are negative; therefore, the chemical bonding between Co and Al atoms increases the stability of compounds. According to elastic constant restrictions, all the six Co–Al compounds are mechanically stable. CoAl alloy with the larger moduli and lower Poisson's ratio is the hard or brittle phase. Moreover, CoAl3, Co3Al, Co2Al5, and Co2Al9 alloys are considered to be ductile materials, which have lower ratio of shear modulus to bulk modulus.

We present an experimental study on the epitaxy and orientational relationships of WO2 and NbO2 films on (0001) Al2O3, (111) MgAl2O4, and (111) MgO substrates, as well as WO2 on (111) SrTiO3. The higher symmetry of the substrate planes compared to the film planes leads to the formation of epitaxial structural variants, and they are related by the surface rotational symmetry elements of the substrates. WO2 and NbO2 crystallize in distorted versions of the rutile structure, and we discuss our findings in context of the rutile unit cell. Our results are applicable to other compounds that occur in (distorted) rutile structures. For the case of NbO2 thin films, we also demonstrate that they can be grown epitaxially on (10$\bar 1$2) and (10$\bar 1$0) Al2O3, lower symmetry surfaces; in these cases, surface symmetry does not induce the formation of epitaxial rotational variants, though domains related by glide symmetry are possible.

We present a simple and quick procedure for the one-pot synthesis of manganese oxides under a basic solvothermal condition in the presence of cationic surfactants acting as the template in a 2-butanol/water solution. Three-dimensional spinel-type MnO2 microspheres composed of small nanoparticles have been fabricated for the first time using our method. Their corresponding electrochemical performances in the applications of supercapacitor electrodes exhibit a good specific capacitance (SC) value of ∼190 F/g at 0.5 A/g and excellent SC retention and Coulombic efficiency of ∼100% and ∼95% after 1000 charge/discharge cycles at 1 A/g, respectively. This suggests its potential applications in energy storage devices. Further, we demonstrate that this solvothermal technique enables the morphological tuning of manganese oxides in various forms such as schists, rods, fibers, and nanoparticles. This work describes a rapid and low-cost technique to fabricate novel architectures of manganese oxides having the desired crystal phase, which will highly benefit various supercapacitor applications.

Multilayer thin films have been widely used for their enhanced mechanical and tribological properties relative to the monolayers of equivalent thickness. However, the mechanical properties of the each constituent layer are rarely investigated due to the difficulty in separating the effects of the constituent layers. An inverse analysis method to identify the elastic moduli of the constituent layers of multilayer films is developed by fitting the finite element calculations with indentation measurements within the framework of numerical optimization. The method is verified against typical monolayer, bilayer, and trilayer film structures both numerically and experimentally. Uniqueness and substrate-independence of the extracted moduli are ensured by the multiple loading–unloading cycles of the indentation tests. The method provides a feasible way to characterize the intrinsic mechanical properties of the constituent layers of multilayered thin films and further to explore the dominant mechanism for the enhancement of their mechanical properties.

Graphene, a single atomic sheet of sp2-bonded carbon atoms arranged in a honeycomb lattice, exhibits extraordinary electrical and mechanical properties, attracting much attention in both academia and industry. The preparation of high quality large-area graphene and the tuning of graphene electronic properties are important topics in this field. In this feature paper, we review our recent work on epitaxial graphene (EG) on SiC(0001). First, we introduce the bottom-up growth mechanism of the first few EG layers on SiC(0001), and the modification of graphene electronic properties by means of surface transfer doping with electron withdrawing materials (F4-TCNQ and MoO3). Next, we summarize the adsorption behaviors of organic (PTCDA, ClAlPc, and C60F48) and inorganic (bismuth) materials on EG/SiC(0001). Finally, as an example of tuning the electronic properties of graphene by reducing its dimensionality, we demonstrate the molecular self-assembly of atomically precise armchair graphene nanoribbons with varying widths and electronic structures.

A straightforward approach allowing three-dimensional (3D) visualization of subsurface deformation beneath nanoindents using reconstructed cross-sectional transmission electron microscopy (TEM) data is demonstrated. This approach relies on generating an array of nanoindents, extracting a thin (<200 nm) cross section using a focused ion beam (FIB) and imaging with a transmission electron microscope. By rotating the orientation of the FIB cross section with respect to the array of nanoindents at the optimal angle, it is guaranteed that a different section of each nanoindent's subsurface plastic zone is contained within the final cross section. Subsequently, TEM images corresponding to different sections are reconstructed into a 3D image of a representative nanoindentation plastic zone. This approach can be extended to any array of nominally identical features that can be patterned with regular spacing and included in a single FIB cross section. It was also found to significantly enhance the throughput of preparing routine site-specific TEM samples, even when 3D visualization is not necessary. In this article, the approach is applied to visualize the plastic zones beneath nanoindents in GaAs (001), for loads of 50–1000 µN.