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A facile approach for improving color purity is explored by the introduction of an angle-robust selective absorber (ARSA) into bottlebrush block copolymer (BBCP)-based one-dimensional (1D) photonic crystals (PCs). The BBCPs of poly[(3-(12-(

The homopolymers P1, P2 and P3 were successfully synthesized by direct CH–CH arylation polymerization in an eco-friendly one-step coupling reaction. They present n-type properties for potential applications as acceptor polymers.

The relationships between the structure and the property of donor–acceptor copolymers based on dithieno[3,2-b:2′,3′-d]pyrrole as a strong donor unit and isoindigo or thiazole as acceptor units are successfully studied.

The amphiphilic conformation of α-helical peptides has important biological functions, such as ion transport, antifreeze, and innate immunity, which can be mimicked by alternating polyisocyanate copolymers. We synthesized poly(allyl isocyanate-alt-(S)-(-)-α-methylbenzyl isocyanate (P(AIC-alt-SMBIC)) and ammonium-containing P(AIC-alt-SMBIC) (N-P(AIC-alt-SMBIC)), ensuring the amphiphilic helical conformation. The benzyl group of SMBIC plays an important role in alternating copolymerization with its steric and electron-withdrawing effects, while AIC provides an alkene group capable of introducing a customized functional group. The P(AIC-alt-SMBIC) with predominantly alternating sequence was acquired at f

Three crosslinkers (1,4-diaminobutane, 1,8-diaminooctane, and 1,6-hexanediol) were selected to produce hydrogen-bonded networks using a simple and effective method. The effects of these crosslinkers on the arrangement of crystalline structures were successfully studied using X-ray diffraction and high-voltage electron microscopy. The hydrogen-bonded isoindigo-based small molecules with 1,4-diaminobutane showed the best performance, with a crystal structure showing long-range order, due to the more suitable length of the 1,4-diaminobutane chain. The hole mobility estimated from hole-only devices based on isoindigo was enhanced from 1.24 × 10

Highly conductive and stable anion exchange membranes (AEMs) are important components of high-performance anion exchange membrane fuel cells (AEMFCs). Here, we report the use of crosslinked poly(arylene ether sulfone) (PAES) AEMs containing quaternary ammonium (QA) and triazolium cations. The crosslinked PAES-triazole-hydroxide membrane (cPAES-TA-OH) had a higher ion exchange capacity (IEC) than that of the non-crosslinked membrane (PAES-TA-OH) owing to the presence of triazolium cations. The IEC values of cPAES-TA-OH and PAES-TA-OH were 1.75 and 1.31 meq/g, respectively. The IEC value affects the water uptake and swelling ratio of a membrane. The water uptake and swelling ratio of cPAES-TA-OH were higher than those of PAES-TA-OH at 30 °C and 80 °C. In addition, hydroxide conductivity and membrane stability were enhanced by crosslinking; the hydroxide conductivity of cPAES-TA-OH was 92.1 mS/cm at 80 °C under 95% RH (in contrast to 86.2 mS/cm for PAES-TA-OH), and its conductivity retention was 67% after treating with 1M NaOH at 80 °C for 24 h (in contrast to 51% for PAES-TA-OH).

The influence of N-substituent and pKa of azole rings has been investigated for the performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Imidazole, benzimidazole, and triazole groups were functionalized on the side chains of poly(phenylene oxide), respectively. Each azole group is categorized by their N-substituent into two types: unsubstituted and methyl-substituted azoles. The membranes with methyl-substituted azoles showed higher phosphoric acid (PA) doping levels with an average increase of 20% compared to those with unsubstituted azoles in the full-doped states. However, unsubstituted azoles more effectively improved the proton conductivity and the membrane with unsubstituted imidazole (IMPPO-H) showed a high anhydrous proton conductivity of 153 mS/cm at 150 °C. In contrast, the membranes with methyl-substituted azoles showed a higher PA retention with an average increase of 81% compared to those with unsubstituted azoles. The higher PA retention of methyl-substituted azoles also led to the higher fuel cell performance with the maximum increase of 95% in the power density. It was also revealed that higher pKa of azoles enhanced the PA retention and the fuel cell performance. Based on the experimental results of PA retention and density functional theory calculations, the PA loss mechanism was also proposed.

We prepared a poly(pyrrole : biphenyldisulfonic acid : pyrrole (Py:BPDSA:Py)) nanocomposite of molybdenum disulfide (MoS2), P(Py:BPDSA:Py)-MoS2, with high crystallinity. The composite is synthesized by oxidative polymerization of Py:BPDSA:Py as a two-monomer-connected precursor (TMCP) linked by ionic bonding on a molybdenum disulfide (MoS2) monolayer. The chemical, structural and morphological characterization of this composite is confirmed by Raman spectroscopy, FT-IR, X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS), and scanning electron microscopy (SEM). The crystal structure is analysed by X-ray diffraction (XRD) and high-voltage electron microscopy (HVEM), which shows a face-centered cubic (FCC) crystal structure for the composite. Nitrogen adsorption–desorption isotherms show an improved specific surface area (91.3 m2 g−1). The electrochemical properties of the composite with a unique crystal structure and a large specific surface area are analysed through cyclic voltammetry (CV), which shows a specific capacitance of 681 F g−1 demonstrating that the composite can be used as an efficient electrode active material for electrochemical energy storage systems.

A high-molecular-weight poly(styrene-co-2-(dimethylamino)ethyl methacrylate-co-acrylonitrile) (ABC)-type terpolymer with a high tensile strength (7.36 MPa) was synthesized using free radical polyme...

High-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) are operated between 120 °C and 180 °C. As a result, they cannot employ Nafion® as an electrode ionomer because the proton conductivity of Nafion® is very low without water. In this study, new polymers (poly(phenylene oxide), PPO) with a phosphate group including methyl phosphonic acid (PPO-MPA) or 6-oxohexyl phosphonic acid (PPO-HPA), which show good proton conductivities, are applied as ionomers and binders to form an electrode. In addition, vinylphosphonic acid (VPA) is investigated as an electrode additive. The PPO-MPA electrode shows a lower wetting angle than that of the PPO-HPA electrode. After the addition of VPA, the PPO-MPA electrode becomes more hydrophobic, whereas the PPO-HPA electrode becomes more hydrophilic. In the FT-IR spectra of the PPO-MPA electrode, the peak associated with the PO32− asymmetric stretch is more blue-shifted than the peak of the polyvinylidene difluoride electrode at a high temperature due to increased amounts of released protons from PPO-MPA, indicating that the binder with a phosphate group improved the proton conductivity of the ionomer in the HT-PEMFC. At 0.2 A/cm2, the performance of the membrane electrode assembly (MEA) using the PPO-MPA cathode increases from 0.55 V to 0.59 V by the introduction of VPA, whereas that using the PPO-HPA cathode decreases from 0.61 V to 0.57 V, which exhibits the same propensity as the hydrophobicity change. The value of charge transfer resistance at 0.6 V estimated by fitting of the electrochemical impedance spectra follows the same trend as the MEA performance. This is attributed to a change in catalyst coverage by phosphoric acid in the electrode by the addition of VPA and not a change in proton conductivity. The possibility of new polymer binders for the HT-PEMFC is demonstrated, and the MEA performance is shown to be influenced by the incorporation of VPA, which is accounted for the change in hydrophobicity of the electrode.

Iridium complex-incorporated monodisperse particles are prepared via surfactant-free emulsion polymerization. For this process, a vinyl-substituted iridium complex (IrV) is synthesized and copolyme...

Despite the importance of structure and properties in organic mixed conductors, there exist very few material systems where the effects of relative crystallinity, crystallite size, and doping conce...

A blend of poly(3-hexylthiophene) (P3HT) and poly(n-hexyl isocyanate-block-2-vinylpyridine) (PHIC-b-P2VP) in a common solvent shows the formation of long-range (micrometer-scale) nanowires of P3HT ...

A well-ordered polymer nanocomposite was prepared as a supercapacitor electrode based on sulfonated graphene oxide (SGO) and a two-monomer-connected precursor (TMCP). Biphenyldisulfonic acid (BPDSA...

Atomically thin molybdenum disulfide (MoS2) films were synthesized on a SiO2/Si substrate by metal-organic chemical vapor deposition (MOCVD). Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy studies reveal the double-atomic-layer structure and the surface element composition of the MOCVD-grown MoS2 films. The photoluminescence measurement demonstrates a strong emission peak with a bandgap of 685.1 nm, attributed to highly efficient radiative transition at the double atomic layer. The contact resistance between the doubleatomic-layer MoS2 film and metal electrode was measured using the transmission-line modeling method. A Ti/Au electrode forms an ohmic contact with the double-atomic-layer MOCVD-grown MoS2 film, exhibiting a resistivity of 100 kΩ. The field-effect transistor based on the double-atomiclayer MoS2 film exhibits an electron mobility of 1.3×10−4 cm2/V·s and an on/off ratio of 6.5×102 at room temperature.

Background. Bacteremia is a major nosocomial infection that frequently occurs in trauma patients, increasing morbidity and mortality. The aim of this study was to identify risk factors and to describe epidemiological patterns for early onset (EOB) and late onset (LOB) bacteremia after trauma.Methods. We retrospectively reviewed medical records of all trauma patients admitted to the surgical intensive care unit and general ward between January 2011 and December 2015. The information was collected for each patient and recorded in a computer database: early onset bacteremia (EOB) was defined as when onset occurred within 7 days after trauma, and late onset bacteremia (LOB) was defined as when onset occurred after 7 days from trauma.Results. Thirty-four patients of 859 (4%) developed bacteremia during their hospital stay: 4 (11.8%) developed EOB, 26 (76.4%) LOB, and 4 (11.8%) patients developed both of them. Sixty events of bacteremia happened to these patients: 9 (15.0%) EOB and 51 (85.0%) LOB. Gram-positive cocci were isolated more frequently than Gram-negative bacilli in both groups. Gram-positive cocci were more frequently isolated in EOB than in LOB; otherwise, there was no statistical significance (77.8% vs. 64.7%,p=0.683). Central line-associated blood stream infection (CLABSI) and surgical site infection (SSI) were the most common identified source for LOB. Presence of liver (OR: 2.66,p=0.035) and pelvic injury (OR: 2.25,p=0.038), gastrointestinal tract perforation (OR: 5.48,p=0.002), and massive transfusion (OR: 3.36,p=0.006) represented risk factors for bacteremia.Conclusions. Presence of pelvic and liver injury on arrival in emergency department, gastrointestinal tract perforation, and massive transfusion within the first 24 hours after trauma appears to be significant risk factors for bacteremia.

We present the facile synthetic platform for the production of amphiphilic bottlebrush block copolymers bearing pyridine pendants through combination of living anionic polymerization (LAP), ring-op...

Well-defined ambipolar block copolymers containing carbazole, oxadiazole moieties, and only one homoleptic iridium(III) complex between the carbazole and oxadiazole blocks were successfully synthesized by sequential living anionic polymerization with controlled molecular weights (Mw), a narrow molecular weight distribution (Mw/Mn < 1.15), and a high conversion yield (98–100%). The optimum conditions for the successful controlled synthesis of an oxadiazole-containing the homopolymer of poly(2-phenyl-5-(6-vinylpyridin-3-yl)-1,3,4-oxadiazole) have been established by controlling the nucleophilicity strength of the carbanion. In addition, the location and concentration of the homoleptic iridium(III) complex were controlled by linking it to 1,1-diphenylethylene, which exhibits monoaddition characteristics in the main chain of the block copolymer.

Mie backscattering-based coloration of water-dispersed polymer particles is investigated. Diluted colloids and light absorber-added colloids are individually prepared to study the scattering properties. Light absorber-added colloids show ~2.9-fold higher colour saturation than diluted colloids because of the effective elimination of Mie forward scattering. Mechanism of selective extraction of Mie backscattering-based colour in the presence of light absorbers is explained by path length difference of Mie forward and backscattering. Using stimuli-responsive polymer particles, Mie scattering colour-based sensors that respond to pH and heavy metal ions are prepared.