Diverse Proton-Conducting Nanotubes via a Tandem Macrocyclization and Assembly Strategy

Macrocycles that assemble into nanotubes exhibit emergent properties stemming from their low dimensionality, structural regularity, and distinct interior environments. Here, we report a versatile strategy to synthesize diverse nanotube structures in a single, efficient reaction by using a conserved building block bearing a pyridine ring. Imine condensation of a 2,4,6-triphenylpyridine-based diamine with various aromatic dialdehydes yields chemically distinct pentagonal [5+5], hexagonal [3+3], and diamond-shaped [2+2] macrocycles depending on the substitution pattern of the aromatic dialdehyde monomer. Atomic force microscopy and in solvo X-ray diffraction demonstrate that protonation of the macrocycles under the mild conditions used for their synthesis drives assembly into high-aspect ratio nanotubes. Each of the pyridine-containing nanotube assemblies exhibited measurable proton conductivity by electrochemical impedance spectroscopy, with values as high as 10-3 S m-1 (90% R.H., 25°C) that we attribute to differences in their internal pore sizes. This synthetic strategy represents a general method to access robust nanotube assemblies from a universal pyridine-containing monomer, which will enable systematic investigations of their emergent properties.

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Preparation of a P(FcA-co-ANI)/graphene composite for application in supercapacitors

High Performance Polymers ◽

10.1177/0954008316652463 ◽

2016 ◽

Vol 29 (5) ◽

pp. 524-532 ◽

Cited By ~ 10

Author(s):

Yunlong Li ◽

Yuying Zheng

Keyword(s):

Electron Microscopy ◽

Electrochemical Impedance ◽

Proton Nuclear Magnetic Resonance ◽

Diffusion Resistance ◽

X Ray Diffraction ◽

Graphene Layers ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

Surface Morphologies

A conducting copolymer of 1,1′-ferrocenediacyl anilide and aniline (P(FcA-co-ANI)) was synthesized, which had a conjugated structure and ferrocene moieties in the main chain. The monomer and copolymer were characterized using proton nuclear magnetic resonance and Fourier-transform infrared (FTIR) spectroscopies. A P(FcA-co-ANI)/reduced graphene oxide (rGO) composite was synthesized by oxidation polymerization, using rGO as a substrate. The characteristic peaks of P(FcA-co-ANI) and rGO were observed in the FTIR spectrum of P(FcA-co-ANI)/rGO. The X-ray diffraction pattern of P(FcA-co-ANI)/rGO exhibited similar peaks to the pattern of P(FcA-co-ANI), except for the absence of the weak broad peak at 9.0° owing to rGO. The surface morphologies of the materials were characterized by atomic force microscopy, transmission electron microscopy and scanning electron microscopy. The interlayer distances of rGO and P(FcA-co-ANI)/rGO were 0.96 and 1.38 nm, respectively. The morphology of the copolymer was spherical, and it contained island structures covering the surface of the graphene layers. The electrochemical properties of the composite were measured by cyclic voltammetry, galvanostatic charge–discharge measurements and electrochemical impedance spectroscopy. The maximum specific capacitance of the composite was 722.5 F/g at 0.5 A/g. The diffusion resistance was very small, and the composites durability was sufficient for subjecting to prolonged oxidation and reduction.

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Synthesis and Characterization of Syndiotactic Polystyrene-Polyethylene Block Copolymer

Polymers ◽

10.3390/polym11040698 ◽

2019 ◽

Vol 11 (4) ◽

pp. 698 ◽

Cited By ~ 1

Author(s):

Lamparelli ◽

Speranza ◽

Camurati ◽

Buonerba ◽

Oliva

Keyword(s):

Direct Synthesis ◽

Gel Permeation Chromatography ◽

Syndiotactic Polystyrene ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Reaction Conditions ◽

Force Microscopy ◽

Synthetic Strategy ◽

Atomic Force

The direct synthesis of syndiotactic polystyrene-block-polyethylene copolymer (sPS-b-PE) with a diblock structure has been achieved. The synthetic strategy consists of the sequential stereocontrolled polymerization of styrene and ethylene in the presence of a single catalytic system: cyclopentadienyltitanium(IV) trichloride activated by modified methylaluminoxane (CpTiCl3/MMAO). The reaction conditions suitable for affording the partially living polymerization of these monomers were identified, and the resulting copolymer, purified from contaminant homopolymers, was fully characterized. Gel permeation chromatography coupled with two-dimensional NMR spectroscopy COSY, HSQC, and DOSY confirmed the block nature of the obtained polymer, whose thermal behaviour and thin film morphology were also investigated by differential scanning calorimetry, powder wide angle x-ray diffraction, and atomic force microscopy.

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Enhancement of barrier and anti-corrosive performance of zinc-rich epoxy coatings using nano-silica/graphene oxide hybrid

Corrosion Reviews ◽

10.1515/corrrev-2020-0034 ◽

2020 ◽

Vol 38 (6) ◽

pp. 497-513

Author(s):

Meiling Zhang ◽

Hui Wang ◽

Ting Nie ◽

Jintao Bai ◽

Fei Zhao ◽

...

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Corrosion Protection ◽

Electrochemical Impedance ◽

Epoxy Coating ◽

X Ray Diffraction ◽

Protection Efficiency ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron

AbstractThis study reports a facile method to prepare silica-coated graphene oxide nanoflakes (SiO2–GO). Results of X-ray diffraction analysis, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and atomic force microscopy reveal that silica was successfully coated on the GO flakes. The effect of SiO2–GO nanosheets on the corrosion protection and barrier performance of the epoxy coating was investigated in this work. Results indicate that the mechanical properties of all coatings added with GO and SiO2–GO were significantly improved. Furthermore, electrochemical impedance and Tafer polarisation curves showed that added 0.5 wt% SiO2–GO nanoflakes into zinc-rich epoxy coating could greatly improve the anti-corrosion performance of the sample, and the corrosion protection efficiency increased from 67.01 to 99.58%.

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Dependence of the mechanical and structural properties of (Ti,Al)N films on the nitrogen content

Journal of Materials Research ◽

10.1557/jmr.1999.0378 ◽

1999 ◽

Vol 14 (7) ◽

pp. 2830-2837 ◽

Cited By ~ 11

Author(s):

C. Jiménez ◽

C. Sánchez-Fernández ◽

C. Morant ◽

J. M. Martínez-Duart ◽

M. Fernández ◽

...

Keyword(s):

Nitrogen Content ◽

Surface Coating ◽

Electron Spectroscopy ◽

Electrochemical Impedance ◽

X Ray Diffraction ◽

X Ray ◽

Force Microscopy ◽

Atomic Force ◽

Nitrogen Contents ◽

Additional Phase

(Ti,Al)N films with increasing nitrogen content were grown by reactive cosputtering and characterized by auger electron spectroscopy, grazing x-ray diffraction, polarization curves, electrochemical impedance spectroscopy, nanoindentation, and atomic force microscopy. For Ti/Al ≈ 1 the Ti1−x AlxN phase is always present, but lower nitrogen contents lead to an additional phase, probably α–Ti(Al), which causes a decrease in hardness and Young's modulus. The increase of nitrogen content results ina decrease of surface roughness or a more compacted surface coating, according to the impedance results.

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Localized electrochemical impedance measurements on nafion membranes: Observation and analysis of spatially diverse proton transport using atomic force microscopy

10.1021/scimeetings.0c01147 ◽

2020 ◽

Author(s):

xiaojiang wang

Keyword(s):

Atomic Force Microscopy ◽

Proton Transport ◽

Electrochemical Impedance ◽

Impedance Measurements ◽

Force Microscopy ◽

Atomic Force ◽

Nafion Membranes

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Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

MRS Proceedings ◽

10.1557/proc-780-y5.5 ◽

2003 ◽

Vol 780 ◽

Author(s):

C. Essary ◽

V. Craciun ◽

J. M. Howard ◽

R. K. Singh

Keyword(s):

Uv Radiation ◽

Photoelectron Spectroscopy ◽

Grazing Angle ◽

X Ray Diffraction ◽

Metal Thin Films ◽

X Ray ◽

Force Microscopy ◽

Si Substrates ◽

Atomic Force ◽

Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

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Low Molecular Weight Microfibers with Light Sensing Properties

Materiale Plastice ◽

10.37358/mp.17.4.4920 ◽

2017 ◽

Vol 54 (4) ◽

pp. 655-658

Author(s):

Andrei Bejan ◽

Dragos Peptanariu ◽

Bogdan Chiricuta ◽

Elena Bicu ◽

Dalila Belei

Keyword(s):

Molecular Weight ◽

Low Molecular Weight ◽

X Ray Diffraction ◽

Aromatic Rings ◽

X Ray ◽

Force Microscopy ◽

Light Sensing ◽

Sensing Applications ◽

Atomic Force ◽

Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

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Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽

10.3390/photonics8060215 ◽

2021 ◽

Vol 8 (6) ◽

pp. 215

Author(s):

Rajeev R. Kosireddy ◽

Stephen T. Schaefer ◽

Marko S. Milosavljevic ◽

Shane R. Johnson

Keyword(s):

Molecular Beam Epitaxy ◽

Molecular Beam ◽

Optical Quality ◽

X Ray Diffraction ◽

Interface Quality ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron ◽

Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

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Ultrafine metal-polymer catalysts based on polyconjugated systems for Fisher–Tropsch synthesis

Pure and Applied Chemistry ◽

10.1515/pac-2019-1114 ◽

2020 ◽

Vol 92 (6) ◽

pp. 977-984

Author(s):

Mayya V. Kulikova ◽

Albert B. Kulikov ◽

Alexey E. Kuz’min ◽

Anton L. Maximov

Keyword(s):

Tropsch Synthesis ◽

X Ray Diffraction ◽

Fischer Tropsch ◽

Force Microscopy ◽

Composite Catalysts ◽

Fe Catalyst ◽

Atomic Force ◽

And Function ◽

Metal Polymer

AbstractFor previously studied Fischer–Tropsch nanosized Fe catalyst slurries, polymer compounds with or without polyconjugating structures are used as precursors to form the catalyst nanomatrix in situ, and several catalytic experiments and X-ray diffraction and atomic force microscopy measurements are performed. The important and different roles of the paraffin molecules in the slurry medium in the formation and function of composite catalysts with the two types of aforementioned polymer matrices are revealed. In the case of the polyconjugated polymers, the alkanes in the medium are “weakly” coordinated with the metal-polymer composites, which does not affect the effectiveness of the polyconjugated polymers. Otherwise, alkane molecules form a “tight” surface layer around the composite particles, which create transport complications for the reagents and products of Fischer-Tropsch synthesis and, in some cases, can change the course of the in situ catalyst formation.

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