The spatial distribution and chemical speciation of tellurium (Te) at the grain boundary (GB) of nickel (Ni)-based alloys are crucial for investigating the tellurium corrosion mechanism. In this work, corrosion products along GBs were investigated by synchrotron-radiation-based microprobe techniques, including micro-X-ray fluorescence, micro-X-ray diffraction and micro-X-ray absorption near-edge structure (μ-XANES), for the first time. A gradually decreasing tendency in the concentration of tellurium from the GB area into the grains was identified, together with the presence of GB corrosion products in the form of nickel telluride (Ni3Te2), as well as nickel–tellurium solid solution. Moreover, both the µ-XANES results and density functional theory results confirmed that the impurity tellurium atoms in the nickel–tellurium solid solution tend to bond with their neighboring nickel atoms through weak covalent interactions, due to the hybrid state of tellurium 2p–nickel 4s. Such an unstable antibonding character from the nickel–tellurium combination is believed to play a key role in weakening the structural stability of nickel-based alloys. The efficient analysis of the tellurium corrosion mechanism based on these feasible synchrotron radiation characterizations will inspire more pertinent experimental investigations.

The diamond coating of tungsten carbide (WC)–cobalt (Co) hard metals has been the focus of various research activities mainly due to growing interest in diamond-coated tools for industrial machining of different materials. In this work, multilayered diamond coatings have been grown on pretreated tungsten carbide–cobalt substrates by hot-filament chemical vapor deposition. Two types of multilayer coatings have been prepared: (a) three-layer (alternating nanocrystalline diamond and microcrystalline diamond films) and (b) five-layer (alternating ultrananocrystalline and microcrystalline diamond films). The morphology, roughness, structure, thickness, adhesion of these coatings have been investigated using atomic force microscopy, field emission gun scanning electron microscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, nanoindentantion and Rockwell C indentation tests at 600 N load. Raman spectra of the two types of samples exhibited sharp characteristic bands of nanocrystalline diamond and a centered peak at 1340 cm−1. The displacement of this peak in relation to the natural diamond peak (1332 cm−1) can be attributed to graphitic inclusions in diamond grain boundaries and the thermal coefficient mismatch of the multilayer coating–substrate system. Roughness surface measurements showed very smooth surfaces for both samples. Although the substrate has a high binder content, the results show that well-adhered chemical vapor deposition diamond multilayer coatings were produced.

Surface tension and capillary forces were measured for water droplets in contact with anisotropic hydrophobic patterns made of microscopic ridges and grooves using a microbalance. Integrated with a charge-coupled device camera, the instrument allowed capturing of the synchronous images of a droplet during its spreading, compression, stretching and detachment. These images were used to analyze the evolution of the droplet shape and quantify its base diameter and contact angle in both the longitudinal and traverse directions. The experiments confirmed that a water droplet spreads preferentially along the longitudinal direction, on top of the ridges, following the continuity of the solid and producing asymmetry in the drop shape. Switching the droplet wetting mode from advancing to receding causes the droplet to symmetrize its shape. It was found that the maximum adhesion between the droplet and hydrophobic pattern coincides with droplet base circularity and apparent contact angles of nearly identical values measured in the longitudinal and traverse directions. These findings confirm that the most stable configuration for a liquid droplet on a rough solid surface appears only when the droplet base is axisymmetric. It is also demonstrated that the Cassie–Baxter equation pertains only to the droplet in the most stable state, where the excess free energy is minimized.

Nanocomposite polymer electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) have been prepared by using ammonium fluoride (NH4F) as salt, dimethylformamide as plasticizer and nanosize alumina (Al2O3) as filler. The ionic conductivity of polymer electrolytes has increased by four orders of magnitude (from 10−7 to 10−3 S/cm) with the addition of plasticizer. The conductivity of nanocomposite plasticized polymer electrolytes has increased by a factor of 3–4 with the addition of the nanofiller (alumina) along with an improvement in mechanical strength. The conductivity shows two maxima with the addition of alumina. X-ray diffraction studies have been carried out to check the crystallinity/amorphicity of polymer electrolytes. The small change in conductivity over the 30–130°C temperature range and conductivity remains nearly constant with time suggests that these electrolytes are desirable for their use in electrochemical devices such as batteries, fuel cells, sensors, supercapacitors and electrochromic devices. The activation energies of these electrolytes have also been calculated and correlated with conductivity results.

This paper presents the results of quantum-chemical calculations of the adsorption and desorption activation energy bonding energy and the results of the interactions between particles (hydrogen (H), oxygen (O), methylene (CH2) and carbon monoxide (CO)) with point defects on a reconstructed hydrogenated diamond surface C(100)-(2×1): a monovacancy, a divacancy and an adatom. The paper describes the most probable single acts of etching and restoration of an ordered surface. It is shown that the most likely single etching acts among the considered processes are the formation of carbon monoxide molecules from adatoms and oxygen from the gas phase. The most effective process of restoring an ordered surface is the attachment of methylene molecules to divacancy defects. It is assumed that some ‘empty’ dimer rows are formed as a result of surface vacancy defect etching. The results can be used to analyze the physical and chemical processes on the diamond surface during reactive ion etching using hydrogen-/oxygen-based plasma.

The present paper reports the structural, optical and electrical properties of zinc phthalocyanine (ZnPc) thin films which were grown by the thermal evaporation technique at different substrate temperatures of 312, 363 and 413 K and dielectric response of sandwich geometry of ZnPc thin films have also been studied within frequency range 1 Hz–50 KHz. The crystal structures of these ZnPc films have been characterized using the X-ray diffraction technique. Raman spectra and photoluminescence have been recorded to study the molecular orientations in the ZnPc films for different substrate temperatures. The absorption spectra of the ZnPc films have shown two absorption bands – namely, the Soret band and Q-band. The activation energy values of these films have been determined to be lying in the range of 0·70–0·75 eV. Hole mobility values of ZnPc films have been calculated by using differential susceptance method. The capacitance and dielectric constant have been found to decrease with increase in frequency.

The authors propose to use glycidyl methacrylate and lauryl methacrylate copolymers to provide the cotton fabric surface with superhydrophobic properties. The modification was carried out by immersion of cotton fabric in solutions of copolymers in methylethylketone and following heat treatment at 140°C. Stability of the superhydrophobic state of polymer coatings is studied during long-term contact with droplets of water and aqueous acidic, alkaline and salt solutions under saturated vapor conditions. Under the conditions of high humidity and absence of contact with the external environment, a low drop evaporation rate is ensured, which allows to trace the long-term change of the contact angle of the sessile drop. The mechanism of stability of superhydrophobic properties is discussed. Polymer coatings that are based on the glycidyl methacrylate and lauryl methacrylate block copolymer provide better stability of superhydrophobic properties compared with the random copolymer. It is shown that modification of the cotton fabric surface by glycidyl methacrylate and lauryl methacrylate copolymers does not affect its vapor permeability.

The authors simulated spreading of solid copper (Cu) and gold (Au) nanoparticles (5–7 nm size) on the (100) face of the same metal by using molecular dynamics. Then, the results obtained for the copper (nanoparticle)/copper (substrate) system were qualitatively compared to some available experimental data on the spreading of copper microparticles (5–20 μm) on the surface of polycrystalline copper. Before simulating the nanoparticle spreading, the size dependence of the melting temperature was investigated for copper and gold nanoparticles. When temperatures were by 25–35 K lower than the copper particle melting temperature, the observed value 40° of the equilibrium contact angle qualitatively agreed with the range 20–25° that the authors evaluated using an experimental snapshot of a copper microparticle on the copper polycrystalline substrate at temperature by 33 K lower than the bulk copper melting point. However, the characteristic spreading times 0·5–10 ns found for nanoparticles in computer experiments differ from that for copper microparticles (3 h ≈ 105 s) by many orders of magnitude. The characteristic times of spreading for copper and gold nanoparticles were also estimated by using the capillary-induced surface diffusion concept, the similarity theory and an available experimental value of the spreading duration for solid copper microparticles. The theoretical estimations in question satisfactorily agree with the authors’ molecular dynamics results.

In this study, substrates of titanium alloyed with 15% zirconium (Ti–15Zr) were anodised by an electrochemical process in order to investigate the changes in their surface morphology with changes in anodisation parameters. The effect of five different electrochemical voltages (10, 20, 30, 40, 50 V) and three different durations (30, 60, 120 min) were studied. The Ti–15Zr nanotubular substrates were then characterised using field emission scanning electron microscopy along with energy-dispersive spectroscopy. Specifically, wider ranges of diameters and lengths were produced with change in the applied potential and duration without losing the highly ordered nature of the nanotubular surface. Furthermore, Medical Research Council cell strain 5 cells were successfully cultured on nanotubular surfaces with different diameters. This study demonstrates that the anodisation parameters can control the nanotubular morphology of commercially available Ti–15Zr dental implants, which can be a promising solution for enhancing cell adhesion and osteogenesis behaviour.