Oligodepsipeptides (ODPs) with alternating amide and ester bonds prepared by ring-opening polymerization of morpholine-2,5-dione derivatives are promising matrices for drug delivery systems and building blocks for multifunctional biomaterials. Here, we elucidate the behavior of three telechelic ODPs and one multiblock copolymer containing ODP blocks at the air–water interface. Surprisingly, whereas the oligomers and multiblock copolymers crystallize in bulk, no crystallization is observed at the air–water interface. Furthermore, polarization modulation infrared reflection absorption spectroscopy is used to elucidate hydrogen bonding and secondary structures in ODP monolayers. The results will direct the development of the next ODP-based biomaterial generation with tailored properties for highly sophisticated applications.

Temperature-memory technology was utilized to generate flat substrates with a programmable stiffness pattern from cross-linked poly(ethylene-co-vinyl acetate) substrates with cylindrical microstructures. Programmed substrates were obtained by vertical compression at temperatures in the range from 60 to 100 °C and subsequent cooling, whereby a flat substrate was achieved by compression at 72 °C, as documented by scanning electron microscopy and atomic force microscopy (AFM). AFM nanoindentation experiments revealed that all programmed substrates exhibited the targeted stiffness pattern. The presented technology for generating polymeric substrates with programmable stiffness pattern should be attractive for applications such as touchpads, optical storage, or cell instructive substrates.

Perovskite solar cells have evolved significantly since their inception. However, stability is still a major concern. We fabricated devices using a glass/ITO/PEDOT:PSS/MAPbI3/PCBM/Ag device configuration. Devices fabricated using the Pb-acetate precursors showed an efficiency of 13%. This work reports the effect of adding excess lead to the precursor and its impact on the light-induced degradation of efficiency. It is found that 5% excess lead is best for devices regarding the performance and stability and devices retained greater than 50% of the initial efficiency after 2 h of prolonged irradiation. We attribute this phenomenon to the formation of PbI2 which induces passivation in the grain-boundaries.

The formation of nanosized porous oxide layers on titanium (Ti) by asymmetric alternating current anodizing in sulfuric acid has been studied using electrochemical techniques. In order to prevent spark discharge at Ti electrode upon its anodization in 1.0 M H2SO4 solution, the magnitude of the cathodic current is reduced using a special electrical circuit consisting of a variable resistor and two diodes. The unique surface treatment approach gives rise to the formation of nanosized porous layer in a very short period of time and without spark discharge. The surface of porous layers thus obtained has in vitro apatite-forming ability.

We report the classical molecular dynamics (MD) study of thermal stability of three two-dimensional (2D) titanium carbides Ti2C, Ti3C2, and Ti4C3 (MXenes). Thermal properties of 2D nanomaterials are of fundamental importance and raise particular interest due to their potential applications in nanoelectronics. To investigate the behavior of Tin+1Cn MXenes during heating, structural parameters such as Lindemann indexes, radial distribution functions, and atomistic configurations were calculated. The analysis of MD data allowed us to obtain approximate values of MXene degradation temperatures that are 1050, 1500, and 1700 K for Ti2C, Ti3C2, and Ti3C4 MXenes, respectively.

Three-dimensional (3D) printed poly (ethylene glycol) diacrylate (PEGDA) objects have been reinforced with 1%, 3% and 5% silica (SiO2) nanoparticles. Rheological characterizations were conducted for each formulation and 3D-printed using a stereolithographic apparatus (SLA) 3D printer. The tensile and compressive properties of the as-printed nanocomposites were investigated and compared with unreinforced samples. Additionally, the mechanical properties of the objects before and after swelling the samples in deionized water were compared with as-printed ones. Adding SiO2 increased the tensile and compressive strengths of the 3D-printed PEGDA. The tensile and compressive strengths of swollen PEGDA/SiO2 nanocomposite specimens were generally higher than the unswollen specimens.

Poly(3,4-ethylenedioxythiophene) (PEDOT) is synthesized through a micellar dispersion that allows incorporation of biomolecules into this conductive polymer layer. A PEDOT:κ-carrageenan (κC) system was obtained by electrodeposition and it was compared with a standard PEDOT:sodium dodecyl sulfate electrode coat. The electrochemical behavior and the oxidation level after 1000 cycles were studied through cyclic voltammetry and μRaman spectroscopy. The oxidation ratio in the PEDOT increased while electrochemical activity decreased in both cases. Moreover, the PEDOT:κC system allowed the immobilization of the acetylcholinesterase enzyme, which retained its activity. The unique combination of properties is a key feature in the bioelectronics field.

Resonant soft x-ray scattering (RSoXS) leverages chemical specificity to characterize thin films but is limited near the nitrogen edge. The challenge is that commercially available x-ray transparent substrates are composed of Si3N4 and thereby absorb incident x-rays and generate incoherent fluorescence. To overcome this challenge, we designed and fabricated Al2O3 free-standing films for use as RSoXS windows. Al2O3 films offer higher x-ray transmittance and minimal fluorescence near the nitrogen edge. As an example, Al2O3 windows allow for nitrogen RSoXS of conjugated block copolymer thin films that reveal domain spacings, which are not apparent with commercially available Si3N4 substrates.

Methods for the control of molecular deposition and orientation are critical for the development of organic electronic devices. Here, we show the fabrication of ribbons of the optical material polydiacetylene (PDA) using a controlled evaporative self-assembly method. The ability to form these ribbons is highly dependent on both the side groups on the PDA as well as the solvent used in the preparation. Arrays of ribbons of one type of PDA, poly[1,6-di(N-carbazolyl)-2,4-hexadiyne], with widths on the order of 1–2 µm and lengths of 100s of micrometers, could be successfully obtained with good orientation.

To systematically investigate the influence of electrolyte substrates on Sr-segregation and SrSO4 formation in (LaSr)(CoFe)O3 (LSCF) cathodes in solid oxide fuel cells, model thin films were grown on Gd-doped ceria (GDC) and on Y-doped BaZrO3 (BZY) electrolytes by pulsed laser deposition and heat treated at 800–1000 °C in synthetic air with a trace amount of SO2. A severe SrSO4 formation was observed in LSCF on GDC as compared with the BZY, especially at low temperature. The difference in Sr-segregation and SrSO4 formation on the LSCF was discussed in relation to Sr diffusion and related elemental redistribution across the interfaces.

Lithium (Li)-ion battery cathode materials are typically coated to improve cycling performance, using aqueous-based coating techniques that require filtering, drying, and even sintering of the final product. Here, spherical LiNi0.6Mn0.2Co0.2O2 particles were coated with nano-Al2O3 using the dry mechanofusion method. This method produced a durable, non-porous Al2O3 coating that is retained during slurry making. Mechanofusion coatings significantly improved Li-ion battery cathode cycling at high voltages, enabling high energy densities, while offering inexpensive, scalable, and environmentally friendly solvent-free synthesis. This opens up new possibilities, since, not being limited by synthesis chemistry, mechanofusion can in principle be used to apply any coating material.

We investigated the connectivity of high-energy random grain boundaries through fractal analyses of specimens with different grain boundary (GB) microstructures in BFe10-1-1 copper–nickel alloy. It was found that the profile of maximum random boundary network possesses a fractal nature and more than one fractal dimension can exist. The fraction of special boundaries and grain size homogeneity can play an important role on GB character distribution. Here, GB microstructures are combined with quantitative materials structure–property relationship models to predict intergranular corrosion properties. The experimental results are accurately consistent with the theoretical predictions.

Theoretical investigations on ferroelectric tunnel junctions (FTJs) with asymmetric electrodes and a composite barrier are presented. A large tunneling electroresistance effect exists for the Pt/SrTiO3/BaTiO3/SrRuO3 junction; on the other hand, exchange of the dielectric and ferroelectric layer stacking sequence can seriously degrade the performance. These correlations are rationalized by the proposed concept of an asymmetry factor, defined as the ratio between the average barrier heights of FTJs for two opposite polarization orientations. We show that a large asymmetry factor is beneficial to FTJs. This work may provide a way to enhance the performance of FTJs by structure engineering.

Allylamine (AA)-functionalized surfaces for cell adhesion and tissue engineering generated by plasma reactions present several disadvantages, such as amine degradation after 1 week of storage in air and difficulty in achieving a highly specific surface functionalization. In this work, polypropylene (PP) and polyethylene (PE) films were functionalized with AA by γ irradiation to enhance adhesion and compatibility without changing intrinsic bulk properties, thus avoiding the disadvantages of plasma synthesis. Irradiation grafting was realized by a direct and pre-irradiation oxidation method. The effect of different parameters studied were characterized by Fourier transform infrared spectra, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and contact angle measurements.

Two different sized As(0) nanoparticles As1 (50 ± 7 nm) and As2 (70 ± 10 nm) are prepared by reducing arsenite with NaBH4 in the pH range 7–9, at controlled temperature (10 and 40 °C). Further, galvanic replacement reaction is used exploiting the reducing nature of As(0) to prepare two different sized hollow gold nanoparticles (HGNPs) AuNP1 (55 ± 7 nm) and AuNP2 (72 ± 7 nm). These HGNPs exhibit high catalytic activity towards 4-nitrophenol reduction under various conditions following first-order kinetics. AuNP1 shows ~6.6 time higher turnover frequency compared with that of AuNP2 due to its smaller size. Both catalysts are recycle able.

Here we present the synthesis of porous platinum–palladium macrobeams templated from high aspect ratio Magnus’ salt needle derivatives. The combination of [PtCl4]2− and/or [PdCl4]2− with [Pt(NH3)4]2+ ions results in salt needles ranging from 15 to 300 µm in length. Electrochemical reduction of the salt templates results in porous macrobeams with a square cross-section. Porous side wall texture and elemental composition was controlled with initial platinum to palladium salt ratio. Macrobeam free-standing films exhibited a specific capacitance up to 11.73 F/g and a solvent accessible surface area of 26.6 m2/g. These salt-templated porous platinum–palladium macrobeams offer a promising material for fuel cell catalysis.

Synthesis of ZIF with zinc, cobalt, or copper was carried out by microwaves. The effect of metal center on morphologies and pores of products was studied. Nitrogen adsorption/desorption onto ZIFs was examined by density functional theory. The micro, meso, and macropores of ZIF-8, Zn/Co-ZIF-8, and Cu/ZIF-8 ranged 99.814–99.969%, 0.055–0%, and 0.031–0.130%, respectively. Average pore sizes of ZIF-8, Zn/Co-ZIF-8, and Cu/ZIF-8 are 1.291, 1.194, and 1.164 nm, respectively. Monolayer saturation limits of nitrogen onto ZIF-8, Zn/Co-ZIF-8, and Cu/ZIF-8 were 21.152, 18.943, and 17.784 mmol/g, respectively. Further, the results included densities, total surface areas, total pore volumes, and average particle sizes of ZIF-8, Zn/Co-ZIF-8, and Cu/ZIF-8.

Bimodal nanoporous platinum (BNP-Pt) is synthesized by using a sacrificial nanoporous copper (NP-Cu) support for oxygen-reduction-reaction (ORR) catalysts in fuel cells. The specific ORR catalytic activity of BNP-Pt increases by the dissolution and removal of supporting NP-Cu, suggesting that the BNP structure improves the intrinsic catalytic properties of platinum. The lattice contraction of BNP-Pt containing residual copper even after NP-Cu removal is milder than predicted by Vegard's law. The BNP structure governs the intrinsic catalytic activity of the platinum by relaxing the lattice contraction and by alloying with copper and/or misfit strain at the Pt/Cu interface.

A broadband magnetoelectric energy harvester, consisting of Fe1−xGax (Galfenol) as the magnetostrictor and a relaxor ferroelectric single crystal as the piezoelectric, has been designed and optimized. Finite element analysis (FEA) has been employed to show that either a linear displacement or a 180° rotation of a magnet is sufficient to achieve maximum stroke from the Galfenol rod, which induces a rhombohedral to orthorhombic phase transition in Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 that produces a large jump in voltage. A rotational design based on a pendulum with an unbalanced mass was fabricated and used to confirm the validity of our FEA model.

In this work, the guest Li+ conduction properties in NaBr–LiBH4 system were investigated. It was suggested that the guest Li+ ions occupy the Na+ sites and BH4− ions substitute the Br− ions in NaBr. The dominant Li+ conduction in NaBr–LiBH4 system was demonstrated by the combination of electrochemical measurements and time-of-flight secondary ion mass spectrometry. The guest Li+ ion conductivity of 15NaBr·LiBH4 was measured to be 1 × 10−7 S/cm at 313 K. The present results indicate that the guest Li+ conductors are not restricted to the previous reported iodides (NaI, KI), but other Li-free compounds have the possibility to become the candidates for the guest Li+ ion conductors.