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Preliminary fabrication of thermoset nanocomposites with aligned carbon nanotubes (CNTs) is demonstrated using magnetic fields in an energy-efficient and quick manner. Bulk application of high-performance polymer nanocomposites is currently limited because scalable manufacturing methods to deliver bulk samples with organized nanofillers are currently missing. In this work, active assembly using external magnetic fields is selected as a solution to provide the balanced benefits of bulk processing capacity and tailorable patterning capability. Magnetically-responsive multi-walled carbon nanotubes (∼35 nm diameter and ∼200 μm length) were fabricated with relatively simple post-growth processing: low-temperature oxygen plasma treatment for improved suspension and dispersion within matrices, and e-beam coating with thin ferromagnetic nickel (Ni) layers (∼40–100 nm) for larger magnetic susceptibility. Dispersion and properties of the plasma-treated and Ni-coated CNTs were evaluated visually using the settlement study and scanning electron microscopy, and quantitatively using Raman spectroscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. Assembly of Ni-coated CNTs was first demonstrated in deionized water, and then in a bisphenol-F based polymer resin (Epon 862). Magnetic assembly behaviors of these two-dimensional nanofillers were studied about the effect of their original dispersion, size, and matrix viscosity. The first sizable fabrication of CNT-thermoset nanocomposite (∼32 mm × ∼32 mm × ∼5 mm sample size) was attempted and demonstrated with the smaller magnetic field in the shorter time (∼400 G application for 40 min), than the previous attempt to assemble CNTs (∼105 G for a few hours). Future work include homogenization of CNT patterns within the nanocomposites by improving the original CNT dispersion and suspension (ferromagnetic filling instead of coating, particle surface treatment, etc.), more complex CNT patterning using magnetic field parameter modulation, and structure-interface-property studies by polymer nanocomposite characterization, specially about transport properties.

A novel method to prepare anodes for water electrolysis cells has been developed, which starts from layers of elemental manganese deposited by physical vapour deposition (PVD) on indium-doped tin oxide (ITO). Oxidation in dry air at 300 °C transforms this metallic Mn layer into a manganese(II)-rich MnOx coating (x = 1–1.3), which also contains a buried layer of an In–Sn alloy originating from reactions with the ITO support. The MnOx films are well connected to the underlying substrate and act as efficient catalysts for water-oxidation catalysis (WOC) at neutral pH. Detailed post-operando analyses using XRD, SEM, TEM and XAS revealed that the dense MnO/Mn3O4 film is virtually not affected by 2 h of electrochemical WOC at E ≈ +1.8 V vs. RHE, corresponding well to the observed good stability of catalytic currents, which is unusual for such thin layers of a MnOx catalyst. The current densities during electrolyses are so far low (i ≈ 50–100 μA cm−2 at pH 7), but optimization of the preparation process may allow for significant improvements. This new, rather easy, and adaptable preparation method for stable, thin-layer MnOx water-oxidation anodes could thus prove to be very useful for a variety of applications.

Understanding oxidation of layered chalcogenide semiconductors is important for device processing, as oxidation can be both an intentional and unintentional result of processing steps. Here, the authors investigate chemical and morphological changes in mechanically exfoliated few-layer MoS2 in oxidizing and inert environments using different microscopies (optical, scanning electron, and atomic force) and spectroscopy (Raman, x-ray photoelectron, and Auger electron) techniques. The environments studied were oxygen, oxygen and water vapor, argon, argon and water vapor, and ultraviolet-generated ozone at temperatures from 25 to 550 °C. Oxidation at low temperatures resulted in the formation of a condensed molybdenum oxide phase and sulfur trioxide gas. At sufficiently elevated temperatures, all the products of oxidation volatilize, resulting in a vapor-phase etch. The kinetics of oxidation and etching depended upon the annealing gas, temperature, time, and the number of layers of MoS2. Conditions can be sele...