Textured nickel ferrite (NFO, NiFe2O4) thin films were deposited at room temperature by chemical solution deposition onto c-plane sapphire substrates. A nanoimprint lithography technique using a polydimethylsiloxane stamp was used to transfer a pattern from a master to the thin film, which was subsequently annealed to crystallize the NFO. Atomic force microscopy scans showed good periodicity and feature profile over a large area which was confirmed with cross-sectional transmission electron microscopy. X-ray diffraction revealed textured single-phase inverse spinel NFO. Magnetic measurements of patterned thin films showed a large reduction in coercivity due to demagnetization factors.

Dual-stage, constant loading-rate followed by constant-load, pyramidal indentation experiments were performed to investigate the strain-rate (10−5–10−1/s) and temperature (295–573 K) dependence of pure magnesium. The estimated total activation energy, Q (0.69–1.01 eV), and apparent activation volume, V* (17–28b3), indicate that plastic deformation is controlled by a dislocation cross-slip mechanism. The results from this work and previous studies confirm that, during pyramidal indentation of Mg, the operative deformation mechanism remains the same over a very wide strain-rate and temperature range.

The lifetime of cyclically loaded devices is often limited by the fatigue resistance of their individual phases. An advanced method is presented for measuring the high-cycle fatigue behavior of materials at the micrometer scale using a nanoindenter. It is based on the cyclic deflection of focused ion beam-fabricated microcantilevers using the continuous stiffness method (CSM). In line with experimental data on bulk nanocrystalline copper, the specimens exhibit grain coarsening followed by the formation of extrusions and a fatigue strength exponent of −0.10. The method is suitable for characterizing single phases and individual components of further complex systems.

We report the use of electrospray to continuously deposit thin films, including patterned films, of a block copolymer (BCP). High substrate temperatures led to vertically oriented cylindrical microdomains at the film surface independent of the solvent composition and deposition rates utilized. Conversely, low substrate temperatures resulted in morphologies that were more sensitive to these parameters, with poorly ordered films of globular structures observed at the lowest temperatures considered. The deposition pattern is defined by spatially varying the electric field at the substrate using an underlying charged grid. These results open up new possibilities for patterned deposition of BCP films with morphological control.

Direct arylation polycondensation (DArP) is an emerging synthetic method of producing conjugated polymers in an environmentally benign and cost-effective manner. We now report the synthesis of hole-transporting conjugated polymers, namely, DPP-OMe (Mn = 7.9 kg/mol) and DPP-F (Mn = 12.6 kg/mol), under microwave-assisted DArP conditions. These two polymers and the previously synthesized 3,6-Cbz-EDOT were evaluated as hole-transporting materials in mesoscopic perovskite solar cells. 3,6-Cbz-EDOT synthesized by DArP exhibited higher hole mobility and better photovoltaic properties than that synthesized by the Stille polycondensation. Moreover, chemical dopants improved the short-circuit current density (Jsc) and fill factor.

Ferroelectric single-crystal-architecture-in-glass is a new class of metamaterials that would enable active integrated optics if the ferroelectric behavior is preserved within the confines of glass. We demonstrate using lithium niobate crystals fabricated in lithium niobosilicate glass by femtosecond laser irradiation that not only such behavior is preserved, the ferroelectric domains can be engineered with a DC bias. A piezoresponse force microscope is used to characterize the piezoelectric and ferroelectric behavior. The piezoresponse correlates with the orientation of the crystal lattice as expected for unconfined crystal, and a complex micro- and nano-scale ferroelectric domain structure of the as-grown crystals is revealed.

Cobalt oxide thin films with different thicknesses were synthesized by atomic layer deposition. After a thermal reduction process, under a controlled atmosphere of hydrogen, it was possible to convert cobalt oxide to metallic cobalt. The different thicknesses were obtained considering from 500 to 2000 cycles of CoCp2/O3. The thin films were characterized by x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray microanalysis, and by magneto-optical Kerr effect measurements. The indirect synthesis process allows us to obtain cobalt oxide and cobalt thin films with controlled thicknesses and extraordinary magnetic properties, with coercivities above 500 Oe.

A thermoresponsive large-area plasmonic architecture, made from randomly distributed gold nanoparticles (GNPs) located at the substrate interface of a cholesteric liquid crystal (CLC) cell, is fabricated and thoroughly characterized. A photo-thermal heating effect due to the localized plasmonic resonance (LPR) mechanism is generated by pumping the GNP array with a resonant light beam. The photo-induced heat, propagating through the CLC layer, induces a gradual phase transition from the cholesteric to isotropic phase. Both the plasmonic and photonic properties of the system as both the selective reflection properties and frequency of the LPR are modulated.

Additive manufacturing used with custom electromyographic sensors has been demonstrated for neuroprosthetic limb manufacturing and is now translating to the clinical environment. These manufacturing methods have dramatically reduced device weight while increasing the capability for multi-finger dexterity. Using wearable electromyography sensors standalone from the prosthetic limb, a new virtual training method has been designed and tested to improve human–machine interaction. This type of training leverages real-time visual feedback to user inputs, supporting improved timing and magnitudes of muscle contractions. The combination of these technologies may provide a stronger affinity between the pediatric patient group and the device.

Multifunctional scaffolds with dual release of small molecular drugs and biomacromolecules have potential in many applications such as cancer postoperative care, which require appropriate administration of anticancer drugs and biomacromolecules in a spatiotemporal manner. Herein, a systematic investigation into the dual release of anticancer drugs and biomacromolecules from the bicomponent nanofibrous scaffolds is performed. Their release behavior is affected by different fabrication techniques and different polymers used. We show that the bicomponent scaffold fabricated by dual-source dual-power emulsion electrospinning enables dual release of anticancer drugs and biomacromolecules in a controlled manner, holding promise for combinational cancer postoperative care.

This research investigates a novel composite of encapsulated paraffin in boron nitride nanotube (BNNT) which is more thermally and chemically stable than carbon nanotube. This composite can achieve high thermal conductivity and, meanwhile, have thermal energy storage capability for efficient thermal management under extreme conditions. Equilibrium molecular dynamics simulations were conducted to study self-diffusion coefficient, thermal conductivity, and specific heat of encapsulated paraffin. The simulation results indicated that the self-diffusion coefficient and thermal conductivity of paraffin could be increased by up to 10 and 7 times, respectively, while specific heat was reduced after encapsulating into BNNT.

With rapid growth of human population and decreasing labefaction of our environment, the usable fresh water is facing severe pollution and global shortage. Bio-inspired engineering and biotemplate-directed engineering thus offer great promise in clean water generation, including desalination, decontamination, and disinfection. This perspective begins with an introduction of solar energy-based interfacial evaporation system inspired by the natural systems of organisms, and then provides a review of the development and recent progress of the interfacial evaporation system for clean water generation. The long-term outlook in this field of clean water generation using bio-inspired interfacial systems is also discussed.

This report is on the synthesis by electrospinning of multiferroic core-shell nanofibers of strontium hexaferrite and lead zirconate titanate or barium titanate and studies on magneto-electric (ME) coupling. Fibers with well-defined core–shell structures showed the order parameters in agreement with values for nanostructures. The strength of ME coupling measured by the magnetic field-induced polarization showed the fractional change in the remnant polarization as high as 21%. The ME voltage coefficient in H-assembled films showed the strong ME response for the zero magnetic bias field. Follow-up studies and potential avenues for enhancing the strength of ME coupling in the core–shell nanofibers are discussed.

Significant progress in nanoscience was achieved through the development of methods and instruments to better comprehend nanoscale properties. We present here a methodology and automated setup to measure layer-by-layer films capacitance in the air immediately after polyelectrolytes adsorption. It presents high accuracy (~0.01 pF) to check the capacitance stabilization during spontaneous drying process in the air, with sensitivity to show electrical signal alternation accordingly to the outermost polyelectrolyte layer. Besides, a linear trend in capacitance was observed similar to UV–vis measurements. This method allows analyzing films electrical properties, affording better choice of materials, thickness, and molecular architecture.

We report on a new type of polymer electrolyte fuel cell based on a hydroxide ion conductive polymer combined with a non-noble chromium–nickel (Cr–Ni) catalyst for the oxygen reduction reaction (ORR). We study variable fractions of Cr in Ni by density functional theory simulating the thermodynamic potentials characterizing the ORR. We found increased ORR catalytic activity employing the rotating disk electrode technique. The polarization curve and power densities measured for the constructed fuel cell indicate considerable performance improvement with the Cr–Ni catalyst. Thus we expect that this kind of fuel cell may open up alternative routes in fuel cell research using non-noble catalysts.

Here, the authors report a detailed method of growing LaAlGe, a nonmagnetic Weyl semimetal, thin film on silicon(100) substrates by molecular beam epitaxy and their structural and electrical characterizations. About 50-nm-thick LaAlGe films were deposited and annealed for 16 h in situ at a temperature of 793 K. As-grown high-quality films showed uniform surface topography and near ideal stoichiometry with a body-centered tetragonal crystal structure. Temperature-dependent longitudinal resistivity can be understood with dominant interband s–d electron–phonon scattering in the temperature range of 5–40 K. Hall measurements confirmed the semimetallic nature of the films with an electron-dominated charge carrier density of ~7.15 × 1021 cm−3 at 5 K.

Oxoammonium cation of 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) was used as an oxidizing dopant of triaryl amines to efficiently and almost quantitatively generate radical cations of the amines or a hole carrier. The doped-triaryl amines yielded an amorphous and homogeneous layer without any residual oxidant or neutral TEMPO molecule through its sublimination or warming the layer. The TEMPO cation-doped spiro-OMeTAD [tetrakis(dimethoxyphenylamine)spirobifluorene] produced a high hole mobility of 2 × 10−4 cm2/Vs. The perovskite solar cell fabricated with the TEMPO cation-doped or residual dopant-free spiro-OMeTAD as the hole-transporting layer displayed a photo-conversion efficiency of 20.1% with durability.

In this study, “within the environment” and “within the contact” in situ tribology techniques are combined in order to study the interfacial processes in lubricated metallic (i.e., aluminum-based) sliding conditions. The evolution of the roughness follows the trend of the coefficient of friction closely, with initially low values followed by higher roughness during steady state. Similarly, the transfer film behavior correlates well with the roughness of the worn surfaces and the subsurface microstructure of the worn surfaces. The effect of normal load on the running-in behavior is also studied in terms of differences in the interfacial processes.

Polymer redox-active materials (redoxmers) have numerous applications in the emerging electrochemical energy storage systems due to their structural versatility, fast-cycling ability, high theoretical capacity as electrode materials, sustainability, and recyclability. This review examines recent developments in improving the cycling performance of such materials and provides a vista on the future research directions.

AgNPs@g-C3N4 composite was synthesized from Ag-containing sol and g-C3N4 powder by the ultrasonic-assisted self-assembly method. The composite has hierarchical pore size distributions, which will be beneficial to the ion transport with different size. Ag nanoparticles with the size of 5 nm successfully adhere on the surface of g-C3N4. The AgNPs@g-C3N4 composite has excellent specific capacitance and specific power performance for the supercapacitors as an electrode material. The specific capacitance of composite is 4 times greater than that of g-C3N4. It can be ascribed to the introduction of Ag nanoparticles that the internal resistance of the composite is significantly decreased.