The wettability of the 304L steel is an important parameter in Liquid Metal Embrittlement studies. Empirically, it is found to be greatly enhanced by pre-exposure to oxygenated liquid sodium. The corrosion interface formed during exposure to sodium has been analyzed at the nanoscale by transmission electron microscopy using the focused ion beam sampling. A thin layer of sodium chromite (Nax CrO2 with x ≤ 1) is detected at the interface validating wetting on an oxide mechanism for the enhanced wetting after pre-exposure. Fracture micromechanisms and the crack path of liquid sodium-embrittled austenitic steel 304L at 573 K have been investigated down to the nanoscale. High-resolution orientation mapping analyses immediately below the fracture surface show that abundant martensitic transformations (γ → α) and twinning occur during deformation of austenite. The preferential crack path is intergranular along the newly formed γ/γ interfaces. It is concluded that these transformations play a major role in the fracture process.

This study describes results from mechanical tests conducted on magnesium single crystals in comparison with polycrystalline magnesium. It was found by impact testing that the magnesium single crystal is highly ductile due to energy absorption by twinning and slip, while the polycrystalline samples fracture easily upon impact. Compressive testing along two orthogonal directions at low plastic strains was also performed. The microstructure studies by electron backscatter diffraction and XRD pole figure analysis revealed profuse ( $10\overline12$ ) twinning when compression is done along the growth plane (72 16 $\overline {88}$ 62). The twinning and interaction between different twin modes resulted in incipient recrystallization at strains as low as 8% at room temperature. Compression along the nearly orthogonal plane (2 2 $\bar{4}$ 15) was marked by a much lower degree of both twinning and recrystallization. The variation in microstructural response with the orientation of loading allows for a wide range for tailoring mechanical properties of pure magnesium single crystals without any need of alloying.

Graphene nanopores are utilized in various notable applications such as water desalination, molecular separation, and DNA sequencing. However, the creation of stable nanopores is still challenging due to the self-healing nature of graphene. In this study, using molecular dynamics simulations we explore the drilling of nanopores through graphene by bombardment with Si-nanoparticles. This enables the Si-passivation along the nanopore rim, which is known as an efficient way to stabilize graphene nanopores. The interplay between graphene and projectile causes the anomalous behaviors such as local maxima depending on particle size. The observations are thoroughly analyzed with interaction energy and shape changes.

6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and pentacene-based high-voltage organic thin film transistors (HVOTFTs) have been fabricated on solid and flexible substrates via a low-temperature (<100 °C) solution-processed and vacuum-deposited fabrication method. A high-k dielectric Bi1.5Zn1Nb1.5O7 and an organic dielectric parylene-C have been incorporated into the transistor design. The reliability of the HVOTFTs was analyzed under flexure, where a nonsaturating I–V characteristic behavior was observed. Here, the HVOTFT exhibited a mobility μ of 0.018 cm2/(V s) and a large breakdown voltage of |V DS| > 120 V and >550 V for TIPS-pentacene and pentacene devices, respectively. The large breakdown voltages are attributed to an organic semiconductor channel region which is partially gated, allowing for a large potential drop. Thiolphenol-based SAMs were used to help improve charge injection. Electrical measurements were also performed with samples designed with a top metal field plate to improve control of the charge carrier within the channel.

New closed-form analytical equations for volume fractions and surface-area-to-volume ratios for architected lattice cellular materials are derived. Prior approximate equations which erroneously over count overlapping volumes and the associated surface area are commonly used in the literature. These equations are found to have up to 184% error for volume fraction calculations for hollow lattices and 211% error for surface-area-to-volume ratio calculations, thus necessitating computational methods to arrive at accurate geometric properties for cellular lattice materials. This work derives new equations which are accurate to better than 1% for both volume fraction and surface-area-to-volume ratio as compared to the computational models. These new equations for cellular lattice materials are applicable to both pyramidal and tetrahedral unit cells as well as to both hollow and solid lattice members. By eliminating the need for numerical models to compute accurate volume fractions and surface-area-to-volume ratios of architected cellular materials, these new analytical equations will enable accurate yet computationally efficient optimization of the physical properties of architected cellular materials.

Sterilization is one of the last stages prior to the implantation of a biomaterial. Therefore, the method should be chosen carefully as this is determinant not to compromise the properties of the material. In this context, three sterilization processes were evaluated as to their effect on the properties of a silane hybrid coating: steam autoclave, ethylene oxide, and hydrogen peroxide plasma. The coating was obtained from a sol consisting of alkoxysilane Tetraethoxysilane and organoalcoxysilane Methyltriethoxysilane (MTES), applied to the Ti6Al4V substrate, to increase its corrosion resistance and biocompatibility. After sterilization, the samples were characterized by scanning electron microscopy, atomic force microscopy, profilometry, wetabillity, and Fourier transform infrared spectroscopy. The electrochemical behavior was monitored by open circuit potential and potentiodynamic polarization curves. The cytocompatibility was evaluated by adhesion, viability, and morphological alterations in the MG-63 cells. The results showed that the protective behavior of the hybrid coating was compromised regardless of the sterilization method. However, the steam autoclave caused more morphological changes on the silane hybrid coating as well as on the Ti6Al4V substrate than the other two sterilization methods. Although the sterilized hybrid coating did not show cytotoxicity, the hybrid coating sterilized by hydrogen peroxide plasma showed a higher percentage of viable cells. The ethylene oxide presented the lowest percentage of viability and the highest cell death rate.

Significant developments in micro-electrical-mechanical systems-based devices for use in transmission electron microscopy (TEM) sample holders have recently led to the commercialization of windowed gas cells that now enable the atomic-resolution visualization of phenomena occurring during gas–solid interactions at atmospheric pressure. In situ TEM study under atmospheric pressures provides unique information that is beneficial to correlating the structure–properties relationship of nanomaterials, particularly under real gaseous environments. We here provide a brief introduction of the advanced instrumentation of windowed gas cells and review recent progress of in situ atomic-resolution TEM study under atmospheric pressures, including some application examples of oxidation and reduction processes, dynamic growth of nanomaterials, catalytic reactions, and “operando” TEM.

The novel visible-light-responsive direct solid-state Z-scheme g-C3N4/BiOI heterojunction has been synthesized successfully by means of a solid phase calcination method and used for the degradation of microcystin-LR (MC-LR). The layered g-C3N4 disperses on the surface of BiOI microspheres. The samples are characterized by FESEM, HRTEM, XRD, FT-IR, UV-vis spectroscopy, XPS, BET, PL, and Mott–Sckottky. The photocatalytic activity and photodegradation mechanism of the as-prepared g-C3N4/BiOI microsphere photocatalysts are conducted under visible light irradiation using MC-LR as the target pollutant. The g-C3N4/BiOI material exhibits superior photocatalytic performance when compared with pure BiOI, the possible reason is the efficient separation of photogenerated carriers at the interface between g-C3N4 and BiOI. The heterostructure is responsible for the improved separation efficiency of photogenerated electron–hole pairs and thus the higher photocatalytic activity. The possible photocatalytic mechanism is proposed based on relative band positions of these two semiconductors.

Pendent-type polymers are attractive materials which allow the flexibility to introduce various redox active moieties that facilitate rapid ion/electron transport and enable charge storage. Here, we demonstrate naphthalene diimide polymers with polynorbornene backbone having N-phenyl, PNAn 5 and N-(4-nitrophenyl), PNNO 6. Small changes in the molecular design have led to a significant difference in bulk material and device properties. PNNO 6 maintained 80% of its capacity at 1C after 10 cycles in a Li-ion coin cell. PNAn 5 displayed exceptionally high charge capacity and rate capability with excellent cyclability, maintaining almost its theoretical capacity at various C-rates throughout 500 cycles.

In this present study, different volume percentages of titanium dioxide nanoparticles were added as dispersions in commercially pure magnesium using the blend-press-sinter powder metallurgy process followed by hot extrusion. The physically blended titanium dioxide nanoparticles dispersoid induced a significant grain refinement in the extruded magnesium matrix. Characterization of the mechanical properties revealed that the increasing volume percentage of titanium oxide nanoparticles dispersion was effective in enhancing the ductility of magnesium without disturbing the strength under tensile loading and enhancing the strength of magnesium without disturbing the ductility under compressive loading. The dominating deformation mechanism in pure magnesium was the dislocation slip, which was subdued by the tensile twinning deformation mechanism due to the increasing presence of titanium dioxide dispersion. The effect of shift in the dominating deformation mechanism was displayed by the elimination of tensile-compressive asymmetry in magnesium when dispersed with 1 vol% of titanium dioxide nanoparticles.

Intercalated and unmodified TiS2 nanomaterials were synthesized and characterized by UV-Visible-NIR spectroscopy, Powder X-Ray Diffraction, and X-Ray Photoelectron and Ultraviolet Photoelectron Spectroscopy. Photoelectron spectroscopy measurements indicated that CoS and Cu2S appeared to be intercalated between sheets of partially or fully oxidized TiS2, which could be solution processed on conductive oxide substrates. The materials were then applied toward water oxidation and evaluated by cyclic voltammetry, chronoamperometry, and impedance measurements. While unmodified TiS2 was not observed to perform well as an electrocatalyst with overpotentials >3 V in 1 M NaOH electrolyte, CoS intercalation was found to lower the overpotential by ∼1.8–1.44 V at 10 mA/cm2. Conversely, Cu2S intercalation resulted in only a modest increase in performance (>2.3 V overpotential). Impedance measurements indicated that intercalation increased the series resistance in the as-prepared samples but decreased the series resistance in oxidized samples.