In this work, we report on the adhesion of HCT116 (human colon carcinoma cells) cultured on nanofibrillar polymethylmethacrylate (PMMA) and SU-8 micropillars substrates. Both surfaces enabled a good cell proliferation and promoted the formation of adherent interconnections with the fabricated nano- and microstructures. The three-dimensional immunofluorescence confocal characterization of the cells on nanotextured PMMA highlighted the expression of well-spread F-actin cytoskeletal networks as well as the presence of focal adhesions. This study provides thus interesting perspectives for further investigations on the force/adhesion mechanisms related to cancer cell growth and proliferation.

LiFe1−xYxPO4 doped (d-LFP) with amounts of yttrium (0.01% < x < 5% w/w) show a remarkable effect on the electrochemical behavior. The d-LPF samples were investigated on the Li extraction/insertion performance through charge/discharge and capacity–voltage curves. The best performance was attained with Y content of x = 1%. The materials were synthesized by a hydrothermal method and characterized by x-ray diffraction (XRD) and scanning electron microscopy–energy dispersive x-ray spectroscopy (SEM–EDX). The XRD studies showed that d-LPF had the same monoclinic structure as the undoped material. The achieved electrode performance has been attributed to the addition of Y3+ ion by stabilizing the orthorhomic structure. The electrode resistance decreases through the Y-doping.

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.

Tin oxide (SnO2) nanoparticles in gram scale quantity were synthesized from inexpensive Sn feedstock by flame oxidation. Selection of optimal feedstock size based on computational fluid dynamics ensures complete conversion of Sn into SnO2 nanoparticles. The rapid melting and oxidation of feedstock in high-temperature oxidative flame endow the crystalline and phase-pure SnO2 nanoparticles, as evident from x-ray diffraction and transmission electron microscopy analysis. Dye-sensitized solar cells fabricated using flame-SnO2 nanoparticles show higher efficiency (ɳ = 2.72%) than that of commercial SnO2 nanoparticles (ɳ = 1.53%). The increased efficiency is attributed to suppression of electron recombination caused by passivation of sub-band-edge surface states.

We present a novel soft-nanoimprint procedure to fabricate high-quality sub-wavelength hole arrays in optically thick films of gold on glass substrates. We fabricate 0.5 × 0.5 mm2 structures composed of a square array of 180 nm-diameter holes with a 780 nm pitch. Optical angular transmission measurements on the arrays show clear extraordinary transmission peaks corresponding to the dispersion of surface plasmon polaritons propagating on either side of the metal film. The transmission features can be strongly controlled by engineering the dielectric environment around the holes. As the nanoimprint procedure enables fabrication of nanoscale patterns over wafer-scale areas at low cost, these imprinted metal nanoparticle arrays can find applications in, e.g., optical components, photovoltaics, integrated optics, and microfluidics.

Poly(acrylic acid) (PAA) and poly(vinylpyrrolidone) (PVP) are both highly safe synthetic polymers approved as pharmaceutical excipients. When their aqueous solutions are mixed, insoluble rigid complex is precipitated. On the other hand, if the dried PAA film was immersed in aqueous PVP solution, swollen PAA/PVP soft hydrogel was obtained. Heated drying of the gel afforded a transparent water-swellable film. The swellable PAA/PVP complex film exhibited favorable properties in medical use. If the film was put on a bleeding site, it swelled, and stuck to a hemorrhaging spot, and efficiently arrested bleeding. It could also prevent the adhesion formation by injured intestines.

Our recent exploration into the use of biodegradable metals and surface treatments resulting in sufficient strength for skeletal reconstruction applications has led to the need to test these devices’ cytotoxicity. More specifically, our group has developed a resorbable magnesium alloy, Mg–1.2Zn–0.5Ca–0.5Mn, that can be strengthened by heat treatment and coated with a ceramic layer offering time-certain resorption of a medical device. This in vitro study shows that these treatments do not result in cytotoxicity. Both heat-treated (HT) and HT + ceramic-coated (sol–gel) coupons demonstrated more than 70% viability. Thus, these processing steps are likely to be useful in producing biocompatible, resorbable implants that incorporate our Mg–1.2Zn–0.5Ca–0.5Mn alloy.

Recently, fully reversible dislocation motion was postulated to result in hysteretic nanoindentation load–displacement loops in plastically anisotropic solids. Since microcracking can also result in hysteretic loops, here we define a new parameter, reversible displacement (RD) that can differentiate between the two. For C-plane LiTaO3 surfaces and five other plastically anisotropic solids, the RD values either increase initially or remain constant with cycling. In contradistinction, for glass and A-plane ZnO surfaces, where energy dissipation is presumably due to microcracking or irreversible dislocation pileups, respectively, the RD values decreased continually with cycling.

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.

Improvement of the performance of renewable electronic devices is a crucial point for the consolidation of this emerging technology. Herein, we develop a supercapacitor based on cellulose, carbon nanotubes, and ionic liquids. A conductive paper prepared by simple acid hydrolysis of cellulose and carboxylated carbon nanotubes was used as an electrode. A cellulose sponge impregnated with 1-n-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide was used as a separator/electrolyte. Electrochemical tests were performed in a two-electrode cell that presented a specific capacitance of 34.37 F/g when considered the active mass and 97.9% of capacitance retention after 5000 charge/discharge cycles.

Bacillus pasteurii was used as synthesis director for the formation of hollow cylinder and helical NiO micro/nanostructure under urea hydrolysis conditions. Bacteria were capable of precipitating nickel product from nickel solution by metabolic processes. An appropriate amount of both water and bacterial solution were required to precipitate the nickel product in good yield. The average crystallite size of NiO was 11.45 nm and lengths of the cylinder and helices were non-uniform (~2–7 µm) and were varied with bacterial body structure template. The present study demonstrates a feasibility of synthesizing bacteria-guided metal oxide crystals for various functional applications.

Stable superhydrophobic coatings were produced from aqueous suspensions of epoxy nanoparticles. The superhydrophobic coatings demonstrated excellent mechanical robustness and chemical resistance. Aqueous solutions of ionic surfactants, nonionic surfactants, and small organic molecules on superhydrophobic coatings could wet the superhydrophobic coatings. However, the superhydrophobicity can be recovered by rinsing the wet surface with water. It was also discovered that, although seemed wetted, the superhydrophobic surface was separated from the solution of ionic surfactant by a layer of ionic surfactant molecules. In contrast, nonionic and small organic molecules could not aggregate on the superhydrophobic surfaces; the coatings were exposed to the solutions.

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.

The optoelectronic and thermal properties of conjugated polymers are frequently tuned via direct synthetic modification of the conjugated repeat unit. It is also well known that these properties are inherently tied to the crystal structure, a factor which is difficult to predict upon slight chemical modification. We show that the crystal structure of random copolymers of 3-alkylthiophenes can be controlled, which in turn affects the optoelectronic properties. Furthermore, we show that the melting transitions smoothly vary between that of the two homopolymers. As such, the composition of copolymers is a convenient handle to predictably control the thermal properties, crystalline morphology, and optoelectronic properties simultaneously.

Glassy organic semiconductors provide a convenient host for dispersing guest molecules, such as dopants or light-emitting chromophores. However, many glass-forming compounds will crystallize over time leading to changes in performance and stability in devices. Methods to stabilize amorphous molecular solids are therefore desirable. We demonstrate that solution-processable glasses can be formed from a mixture of 8,8′-biindeno[2,1-b]thiophenylene (BTP) atropisomers. While the trans isomer of methylated BTP, (E)-MeBTP crystallizes in spin-cast films, the addition of (Z)-MeBTP slows the growth of the spherulites. X-ray scattering and optical microscopy indicate that films containing 40% (Z)-MeBTP do not crystallize, even with the addition of nucleation agents and aging for several months.

A model-guided design methodology for polymer composite electromagnetic (EM) interference shields is presented. The approach utilizes measurement of intrinsic complex EM parameters, predictive modeling of absorbing geometries in the COMSOL environment, and subsequent fabrication using 3D printing and compression molding. The viability of the first two steps in the approach was confirmed using a commercially available conductive nano-filled polymer composite filament, as well as a model system from the literature. Initial results suggest that the addition of periodically placed air-filled pores within the conductive polymer composite can lead to lower reflection loss and higher absorption bandwidths.

Dual-coated barium titanate (BT) particles were prepared using dopamine (DP) in conjunction with bromine (Br) in order to enhance the dielectric constant of silicone rubber (SR) composites containing evenly distributed BT particles. The results showed that both DP and Br were deposited on the BT particles. The dielectric constant of the SR/BT composite was significantly increased from 3.6 to 4.7 at 1 kHz with the addition of BT modified with dopamine (DP–BT). Moreover, the dielectric constant further rose to 4.9 at 1 kHz when the DP–BT particle was grafted with bromine (Br–DP–BT).

In this paper, the Lewis base character of 3-aminopropyltrimethoxysilane (3-APTMS), an imine derivative of siloxane, and an indole monomer were shown to enable the reduction of gold cations in acetone. The Lewis acid–base adduct of indole monomers and gold formed a polyindole–gold nanoparticle sol. Similarly, the Lewis acid–base adduct of 3-APTMS and gold enabled the formation of gold nanoparticles in the presence of acetone. The polyindole–gold nanoparticle sol and siloxane–gold nanoparticles underwent self-assembly into a polymeric nanofluid that was suitable for casting membranes. The use of these membranes as a potentiometric ion sensor for both cations and anions was considered; a common nonspecific ion exchange molecule, sodium tetraphenylborate, and the polymeric nanofluid were used to prepare an anion sensor and a cation sensor.

Direct urea fuel cells were fabricated using CuNi-plated polymer cloth for anode catalyst and current collector, and Pt-black for cathode catalyst. The output power was significantly enhanced by coating the CuNi cloth with a conducting polymer, poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT*PSS). The open circuit voltage, 0.80 V and the maximum output power, 3.0 mW/cm2 were obtained for the fuel of 0.5 M urea water solution under ambient conditions. Improvement over the cell structure demonstrated to lighten a light emitting diode.

We discuss relationships between transparent supercapacitor performance and the morphology of its ZnO nanostructured electrodes. The electrodes with different morphologies were prepared by magnetron sputtering and postdeposition annealing. They were decorated with MnO2 nanostructures and tested in symmetric transparent supercapacitors. The capacitances for discharging at 10 µA/cm2 were in the range of 20–53 µF/cm2, meaning that an increase of 250% in capacitance can be obtained by optimizing the electrode morphology. Optimal morphologies were hierarchical with a large range of pore sizes available. The worst performing had the smallest range of pore sizes. Best devices exhibited transparencies above 90%.