Fuel cells based on polymer electrolyte membranes (PEM) show promise as a means of energy conversion for wide range applications both in the transportation sector and stationary power production due to their high charge density low operating temperatures. While structure transport bulk PEMs fuel cell have been studied extensively, much less is known about these materials at interfaces under confinement, conditions that are highly relevant membrane electrode assembly working PEM cell. Using...

Ion-conductive polymers, or ionomers, are critical materials for a wide range of electrochemical technologies. For optimizing the complex heterogeneous structures in which they occur, there is need to elucidate governing structure-property relationships, especially at nanoscale dimensions where interfacial interactions dominate overall response due confinement effects. It widely acknowledged that polymer physical behavior can be drastically altered from bulk when under and literature replete...

Abstract In this work, halogen‐free, flame‐retarded polyethylene was investigated to study the effect of inorganic fillers on improvement flame retardancy and suppression smoke density. Through analyses thermal stability density, it found that developed by magnesium hydroxide could effectively be increased additional incorporation zinc borate talc. Furthermore, a synergistic observed when talc were incorporated together. This result confirmed observation fire performance with cone...

Acid−base switchable supramolecular dendronized polyacetylenes (DPAs) with increasing steric bulk on going from generation one [G1] to three [G3], were constructed using multiple self-assembly processes between Fréchet-type [G1]−[G3]-dendritic dialkylammonium salts and a dibenzo[24]crown-8-containing polymer. The formation of the systems is acid−base either an ON (rodlike polymers) or OFF (flexible state. Thus, by controlling superstructures polymers [G1]−[G3] dendrons, it possible induce...

We investigate the effect of ordering temperature (T) and film thickness (hf) on surface morphology flow-coated block copolymer (BCP) films asymmetric poly(styrene-block-methyl methacrylate). Morphology transitions observed ordered by atomic force microscopy (AFM) are associated with a perpendicular to parallel cylinder BCP microphase orientation transition respect substrate increasing hf. "Hybrid" patterns for intermediate hf between these limiting morphologies correspondingly interpreted...

Perfluorinated ionomers, in particular Nafion, are an essential component hydrogen fuel cells, as both the proton exchange membrane and binder within catalyst layer. During normal operation of a cell, ionomer will progressively swell deswell response to changes hydration, resulting mechanical fatigue ultimately failure over time. In this study, we have developed implemented cantilever bending technique order investigate swelling-induced stresses biaxially constrained Nafion thin films. When...

We investigate the utility of Langmuir adsorption measurements for characterizing nanoparticle-substrate interactions. Spherical CdSe/ZnS core-shell nanoparticles were chosen as representative particles because their widespread use in biological labeling and relatively monodisperse dimensions. In particular, quantum dots functionalized with 11-mercaptoundecanoic acid, we utilized an amine-terminated self-assembled monolayer (SAM) a model substrate. SAMs different end-groups (-CH(3) -COOH)...

A novel strategy for a tunable sigmoidal wetting transition from superhydrophobicity to superhydrophilicity on continuous nanostructured hybrid film via gradient UV-ozone (UVO) exposure is presented. Along single surface (40 mm), we could visualize the superhydrophobic (thetaH2O > 165 degrees and low contact angle hysteresis) (165 thetaH2O 10 ) superhydrophilic < within 1 s) regions simply through optical images of water droplets surface. The prepared layer-by-layer assembly negatively...

We quantify the interfacial nanostructure and corresponding water transport kinetics in thin films of Nafion which are known to show nonbulk like properties using neutron reflectivity (NR) quartz-crystal microbalance (QCM) measurements integrated with in-situ, controlled relative humidity environments. Rigorous fitting NR data under humidified conditions reveals that a hydrophilic organosilicate substrate induces an layering domains parallel whereas hydrophobic analogue does not trigger this...

This study introduces the development and application of advanced scanning LiDAR system, SMART MK-II(Samwoo TCS co., Ltd), designed for early detection wildfires industrial fires. Traditional fire methods face limitations due to diverse atmospheric conditions, topographical factors, variability in smoke characteristics. To address these challenges, monitoring systems with spatial resolutions below 30 meters are essential. The MK-II employs dual wavelengths (532 nm 1064 nm) provides...

Air pollution is a persistent environmental and public health challenge, particularly in industrial areas characterized by diverse diffuse emission sources. This study demonstrates the application of an advanced scanning LiDAR system for real-time monitoring particulate matter (PM2.5, PM10) detection illegal emissions Gyeonggi Province, South Korea. The employs remote sensing technology, enabling 360&amp;#176; atmospheric scans within 5 km radius at 30-minute intervals, with spatial...

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTEnvironment-Controlled Spin Coating To Rapidly Orient Microdomains in Thin Block Copolymer FilmsSangcheol Kim, R. M. Briber, Alamgir Karim, Ronald L. Jones, and Ho−Cheol KimView Author Information Department of Materials Science Engineering, University Maryland, College Park, Maryland 20742-2115; Polymers Division, National Institute Standards Technology, Gaithersburg, 20899; IBM Almaden Research Center, 650...

Heterojunction devices of Ge(1-x)Sn(x) / n-Ge were grown by solid source molecular beam epitaxy (MBE), and the mid-infrared (IR) photocurrent response was measured. With increasing Sn composition from 4% to 12%, spectra became red-shifted, suggesting that bandgap alloys lowered compared pure Ge. At a temperature 100 K, wavelengths peak shifted 1.42 µm for Ge (0% Sn) 2.0 12% Sn. The bias dependence device showed optimum reverse > 0.5 volts saturated photocurrent. responsivity estimated be...

Patterned multilayer films composed of poly(allylamine hydrochloride) (PAH) and poly(sodium 4-styrenesulfonate) (PSS) were prepared using dip spin self-assembly (SA) methods. A silicon substrate was patterned with a photoresist thin film conventional photolithography, PAH/PSS multilayers then deposited onto the surface or SA. For SA, on retained, despite high centrifugal forces involved in depositing polyelectrolytes (PEs). The formed by immersing PE-coated substrates acetone for 10 min....

Abstract Transparent conducting Cu-doped NiO thin films were deposited on quartz glass substrates by radio frequency magnetron spattering. The fabricated all in amorphous phase. A relatively high transmittance of 73% was achieved. density ratio Ni 3+ /(Ni 2+ + ) ions the decreased with increasing O 2 gas pressure fabrication chamber, which caused a decrease carrier concentration films. also led to increase Hall mobility. By controlling chamber and substrate temperature, p-type transparent...

A new mixing process was explored to increase further the fracture toughness and investigate toughening mechanisms of epoxy/nylon blend. In this process, without mechanical mixing, mixtures epoxy premade nylon 6 powder were heated curing agent specific temperatures, referred as "mixing temperature." For blends, at sufficiently high a semi-interpenetrating network-like structure can be developed interphase via reaction between amine end group epoxide group. The depth extent depends on...

A new approach to create layer-by-layer assembled multilayer ultrathin films with well-defined micropatterns in a short process time is introduced. To achieve such high line resolution organic films, microfluidic channels were combined the convective self-assembly employing both hydrogen bonding and electrostatic intermolecular interactions. The initially filled polymer solution by capillary pressure, residual was then removed spinning process. Micropatterns clear boundaries obtained, small...

ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication the EditorNEXTDewetting and Layer Inversion of Inverted PVP/PS Bilayer FilmsHuiman Kang, Seung-Heon Lee, Sangcheol Kim, Kookheon CharView Author Information School Chemical Engineering Institute Processes, Seoul National University, 151-744, Korea Cite this: Macromolecules 2003, 36, 23, 8579–8583Publication Date (Web):October 18, 2003Publication History Received3 April 2003Revised4 October 2003Published online18 inissue 1...

A magnetic tunnel junction (MTJ) can detect microwave field due to the interplay between ferromagnetic resonance and tunneling magnetoresistance. Based on fact that resistance change is quadratically proportional rf field, we have designed a mixing circuit in which two microwaves interfere, giving rising dc voltage containing phase difference microwaves. With ability intensity phase, MTJ-based device may be used for on-chip network analyzer spectrum analyzer.

Abstract The temperature dependence of thermal, morphological, and rheological properties amphiphilic polyurethanes was examined with differential scanning calorimetry (DSC), wide‐angle X‐ray scattering (WAXS), small‐angle (SAXS), measurements, Fourier transform infrared spectroscopy. Multiblock (MPU) triblock (TPU) were synthesized two crystallizable segments—poly(ethylene oxide) (PEO) as a hydrophilic block poly(tetramethylene (PTMO) hydrophobic block. DSC WAXS measurements demonstrated...

Al2O3- and MgO-based magnetic tunnel junction (MTJ) sensors were designed fabricated using microfabrication techniques. This study revealed that in the case of Al2O3-based sensors, shape anisotropy free NiFe electrode resulted a linear hysteresis-free tunneling magnetoresistance (TMR) curve. These exhibited TMR values between 27% 30% sensitivity up to 0.4%/Oe over field range − 40 Oe. In CoFeB/MgO/CoFeB MTJ alone was not sufficient achieve MR response. A superparamagnetic layer used desired...