Detonation Nanodiamond and Onion‐Like‐Carbon‐Embedded Polyaniline for Supercapacitors

The detonation nanodiamond is a versatile low‐cost nanomaterial with tunable properties and surface chemistry. In this work, it is shown how the application of nanodiamond (ND) can greatly increase the performance of electrochemically active polymers, such as polyaniline (PANI). Symmetric supercapacitors containing PANI‐ND nanocomposite electrodes with 3–28 wt% ND show dramatically improved cycle stability and higher capacitance retention at fast sweep rate than pure PANI electrodes. Contrary to other PANI‐carbon nanocomposites, specific capacitance of the selected PANI electrodes with embedded ND increases after 10 000 galvanostatic cycles and reaches 640 F g^?1, when measured in a symmetric two‐electrode configuration with 1 M H₂SO₄ electrolyte. The demonstrated specific capacitance is 3–4 times higher than that of the activated carbons and more than 15 times higher than that of ND and onion‐like carbon (OLC).     

Revealing equilibrium and rate constants of weak and fast noncovalent interactions

Rate and equilibrium constants of weak noncovalent molecular interactions are extremely difficult to measure. Here, we introduced a homogeneous approach called equilibrium capillary electrophoresis of equilibrium mixtures (ECEEM) to determine k(on), k(off), and K(d) of weak (K(d) > 1 μM) and fast kinetics (relaxation time, τ < 0.1 s) in quasi-equilibrium for multiple unlabeled ligands simultaneously in one microreactor. Conceptually, an equilibrium mixture (EM) of a ligand (L), target (T), and a complex (C) is prepared. The mixture is introduced into the beginning of a capillary reactor with aspect ratio >1000 filled with T. Afterward, differential mobility of L, T, and C along the reactor is induced by an electric field. The combination of differential mobility of reactants and their interactions leads to a change of the EM peak shape. This change is a function of rate constants, so the rate and equilibrium constants can be directly determined from the analysis of the EM peak shape (width and symmetry) and propagation pattern along the reactor. We proved experimentally the use of ECEEM for multiplex determination of kinetic parameters describing weak (3 mM > K(d) > 80 μM) and fast (0.25 s ≥ τ ≥ 0.9 ms) noncovalent interactions between four small molecule drugs (ibuprofen, S-flurbiprofen, salicylic acid and phenylbutazone) and α- and β-cyclodextrins. The affinity of the drugs was significantly higher for β-cyclodextrin than α-cyclodextrin and mostly determined by the rate constant of complex formation.     

An automated slide scanning system for membrane filter imaging in diagnosis of urogenital schistosomiasis

Traditionally, automated slide scanning involves capturing a rectangular grid of field-of-view (FoV) images which can be stitched together to create whole slide images, while the autofocusing algorithm captures a focal stack of images to determine the best in-focus image. However, these methods can be time-consuming due to the need for X-, Y- and Z-axis movements of the digital microscope while capturing multiple FoV images. In this paper, we propose a solution to minimise these redundancies by presenting an optimal procedure for automated slide scanning of circular membrane filters on a glass slide. We achieve this by following an optimal path in the sample plane, ensuring that only FoVs overlapping the filter membrane are captured. To capture the best in-focus FoV image, we utilise a hill-climbing approach that tracks the peak of the mean of Gaussian gradient of the captured FoVs images along the Z-axis. We implemented this procedure to optimise the efficiency of the Schistoscope, an automated digital microscope developed to diagnose urogenital schistosomiasis by imaging Schistosoma haematobium eggs on 13 or 25 mm membrane filters. Our improved method reduces the automated slide scanning time by 63.18% and 72.52% for the respective filter sizes. This advancement greatly supports the practicality of the Schistoscope in large-scale schistosomiasis monitoring and evaluation programs in endemic regions. This will save time, resources and also accelerate generation of data that is critical in achieving the targets for schistosomiasis elimination.     

Hierarchical micro- and mesoporous carbide-derived carbon as a high-performance electrode material in supercapacitors

Ordered mesoporous carbide-derived carbon (OM-CDC) materials produced by nanocasting of ordered mesoporous silica templates are characterized by a bimodal pore size distribution with a high ratio of micropores. The micropores result in outstanding adsorption capacities and the well-defined mesopores facilitate enhanced kinetics in adsorption processes. Here, for the first time, a systematic study is presented, in which the effects of synthesis temperature on the electrochemical performance of these materials in supercapacitors based on a 1 M aqueous solution of sulfuric acid and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid are reported. Cyclic voltammetry shows the specific capacitance of the OM-CDC materials exceeds 200 F g(-1) in the aqueous electrolyte and 185 F g(-1) in the ionic liquid, when measured in a symmetric configuration in voltage ranges of up to 0.6 and 2 V, respectively. The ordered mesoporous channels in the produced OM-CDC materials serve as ion-highways and allow for very fast ionic transport into the bulk of the OM-CDC particles. At room temperature the enhanced ion transport leads to 75% and 90% of the capacitance retention at current densities in excess of ～10 A g(-1) in ionic liquid and aqueous electrolytes, respectively. The supercapacitors based on 250-300 μm OM-CDC electrodes demonstrate an operating frequency of up to 7 Hz in aqueous electrolyte. The combination of high specific capacitance and outstanding rate capabilities of the OM-CDC materials is unmatched by state-of-the art activated carbons and strictly microporous CDC materials.     

Ionic liquids as catalytic additives for the acceleration of the photopolymerization of poly(ethylene glycol dimethacrylate)s

BACKGROUND: The fast development of practical applications of photopolymerizable compositions (PPCs) leads to a growing demand for the elaboration of novel monomers and simultaneously for the investigation of three‐dimensional polymerization mechanisms including the possible influence of initiator, additives, etc. The aim of the current study is to explore and clarify the role of ionic liquids (ILs) as environmentally friendly catalytic additives in the photopolymerization of poly(ethylene glycol dimethacrylate)s. RESULTS: The photopolymerization of triethylene glycol dimethacrylate (TEGDM) and poly(ethylene glycol‐400 dimethacrylate) (PEGDM) in the presence of various ILs both imidazolium‐based, i.e. [1‐methyl‐3‐alkylim]⁺ (CF₃SO₂)₂N^? (im = imidazolium; alkyl = C₂H₅, C₄H₉, C₁₄H₂₉), and phosphonium‐based, i.e. [P⁺ (C₆H₁₃)₃(C₁₄H₂₉)]X^? (X^? = PF₆^?, BF₄^?, (CF₃SO₂)₂N^?, Cl^?), as catalytic additives was investigated. The influence of the concentration of the ionic salts as well as the nature of the ILs upon the photopolymerization was studied in detail. It was found that imidazolium ILs accelerate TEGDM photopolymerization and suppress the polymerization of PEGDM. In contrast, polymerization of PEGDM with extra small amounts of phosphonium ionic solvents proceeded at a high rate and offered access to new polymers and the utilization of low‐reactivity monomers in PPCs. CONCLUSION: The most striking advantage is that the use of certain ILs permits the control of polymerization rate to achieve maximum oligomer conversion. Copyright © 2007 Society of Chemical Industry     

Two‐dimensional long‐flexible fiber simulation in simple shear flow

Long‐flexible fiber orientation under the influence of a flow field is an important engineering problem. One can encounter this problem in many fields. For example in fiber reinforced thermoplastics produced in both injection and compression molding, fiber orientation affect final part properties. Fiber orientation models are constructed for short fibers in a simple shear flow case and though this case is important it is not the general case. In this work we extract rotational friction coefficients from Jeffery's model, create a general case long‐flexible fiber orientation model, and apply it in a simple shear flow. POLYM. COMPOS., 37:2425–2433, 2016. © 2015 Society of Plastics Engineers     

Electronic structure and spectral properties of the triarylamine-dithienosilole dyes for efficient organic solar cells

The recently synthesized high-performance triarylamine dyes with the dithienosilole π-conjugated spacer for efficient organic solar cells are calculated at the density functional theory (DFT) level with the Bader approach for the quantum theory of atoms in molecule (QTAIM) analysis. The presence of stabilizing intramolecular hydrogen bonds and Van der Waals interactions in the dye molecules is predicted and the energies of these interactions are estimated. The electronic bands nature in absorption spectra of the dyes is determined by the time-dependent DFT calculations with a linear response methodology using B3LYP and BMK hybrid functionals. Relations between incident light absorption intensity in the first long-wavelength band of the dye, its polarization, HOMO-LUMO orbital nature and the driving force of electron injection to the semiconductor are discussed.     

Synthesis,photo- and electroluminescent properties of norbornene based platinum-containing copolymers

Norbornene based monomers containing the 2-phenylpyridinato–N,C²′ platinum(II) complex bonded by acetylacetonate or pyrazolonate anchor groups were synthesized and copolymerized with a carbazole-containing norbornene comonomer by ring-opening metathesis polymerization (ROMP). The photo- and electroluminescence spectra of the resulting Pt-copolymers are similar. They consist of broad bands with maxima at 495, 530 and 565 nm which arise from the mixed ligand centered (LC) and metal to ligand charge transfer (MLCT) transitions. The copolymer with the cyclometalated platinum(II) complex bonded to the polymer chain via the pyrazolonate anchor group revealed the highest brightness of electroluminescence (260 cd/m² at 21 V).     

Controlled Intracellular Release of Peptides from Microcapsules Enhances Antigen Presentation on MHC Class I Molecules

To understand the time course of action of any small molecule inside a single cell, one would deposit a defined amount inside the cell and initiate its activity at a defined moment. An elegant way to achieve this is to encapsulate the molecule in a micrometer‐sized reservoir, introduce it into a cell, remotely open its wall by a laser pulse, and then follow the biological response by microscopy. The validity of this approach is validated here using microcapsules with defined walls that are doped with metallic nanoparticles so as to enable them to be opened with an infrared laser. The capsules are loaded with a fluorescent antigenic peptide and introduced into mammalian cultured cells where, upon laser‐induced release, the peptide binds to major histocompatibility complex (MHC) class I proteins and elicits their cell surface transport. The concept of releasing a drug inside a cell and following its action is applicable to many problems in cell biology and medicine.