Comparative Study of Bis-Schiff Case Containing Conjugated Oligomers Based on Phosphate and Silane Moieties: Investigation of Photophysical and Thermal Properties.

Oligo(azomethine)s bearing phosphate and silane moieties were the subject of an investigation within this study. The initial stage involved the synthesis of two Schiff base monomers, denoted as SCH-1 and SCH-2 (SCHs), each possessing a pair of hydroxyl functional groups. This was achieved through a loss of water between the aldehyde and diamine precursors.

TEM at millikelvin temperatures: Observing and utilizing superconducting qubits.

We present a case for developing a millikelvin-temperature transmission electron microscope (TEM). We start by reviewing known reasons for such development, then present new possibilities that have been opened up by recent progress in superconducting quantum circuitry, and finally report on our ongoing experimental effort. Specifically, we first review possibilities to observe a quantum mechanically superposed electromagnetic field around a superconducting qubit.

Synthesis and Characterization of a Carbazole-Based Schiff Base Capable of Detection of Al in Organic/Aqueous Media.

A new fluorescence probe (L) selectively detecting Al ions was synthesized via the condensation reaction, and characterized using UV-Vis, FT-IR, H-NMR and C-NMR spectroscopic techniques. The limit of detection for Al ions of this synthesized probe was found to be 9.29 × 10 M, while the Ka constant value was determined to be 1.

Frequency-Dependent Piezoresistive Effect in Top-down Fabricated Gold Nanoresistors.

Piezoresistive strain gauges allow for electronic readout of mechanical deformations with high fidelity. As piezoresistive strain gauges are aggressively being scaled down for applications in nanotechnology, it has become critical to investigate their physical attributes at different limits. Here, we describe an experimental approach for studying the piezoresistive gauge factor of a gold thin-film nanoresistor as a function of frequency.

On the Dynamics of Intrinsic Carbon in Copper during the Annealing Phase of Chemical Vapor Deposition Growth of Graphene.

In chemical vapor deposition (CVD) growth of graphene, intrinsic carbon in copper has been shown to play a role, especially during the nucleation phase. Here, we report experimental results on depletion of carbon from the bulk of a Cu foil to its surface at different hydrogen pressures, which explain new aspects of the interplay between hydrogen and intrinsic carbon prior to growth. We observed that rising H pressure boosts carbon depletion to the surface, but at the same time, at elevated H pressures, the graphitic film formed on the Cu surface is etched away at a faster rate.

Spontaneous Nucleation and Growth of Graphene Flakes on Copper Foil in the Absence of External Carbon Precursor in Chemical Vapor Deposition.

In this work, we uncover a mechanism initiating spontaneous nucleation of graphene flakes on copper foil during the annealing phase of chemical vapor deposition (CVD) process. We demonstrate that the carbon in the bulk of copper foil is the source of nucleation. Although carbon solubility in a pure copper bulk is very low, excess carbon can be embedded inside the copper foil during the foil production process.

Synthesis, Characterization and Fluorescence Quantum Yields of Thermally Resisted Shinning Polymers Containing Thiophene and Azomethine Units.

Poly(azomethine)s containing thiophene with bridges pyridine, sulphur and oxygen were synthesized in two steps. Before, thiophene centric dialdehyde (DIAL-Th) compound was synthesized via elimination reaction of 4-hydroxy benzaldehyde with thiophene bromide. Then, poly(azomethine)s containing thiophene (PAZ-Th) unit were synthesized from condensation reactions of DIAL-Th with pyridine-3,5-diamine, 4,4'-thiodianiline and 4,4'-oxydianiline.

Superbat: battery-like supercapacitor utilized by graphene foam and zinc oxide (ZnO) electrodes induced by structural defects.

The current work presents a hybrid type of energy storage device composed of both graphene foam and zinc oxide electrodes, which exhibits both the electrochemical performance of a supercapacitor with a relatively higher power density, and a battery with a relatively higher energy density as compared to each individual component as single devices. Te hybrid's improved performance was correlated to the defective structure of the electrodes. To enhance the electrochemical performance of supercapacitors, it is necessary to have a well-defined mass, shape, and surface area of electrode materials.

Focusing short-wavelength surface plasmons by a plasmonic mirror.

Emerging applications in nanotechnology, such as superresolution imaging, ultra-sensitive biomedical detection, and heat-assisted magnetic recording, require plasmonic devices that can generate intense optical spots beyond the diffraction limit. One of the important drawbacks of surface plasmon focusing structures is their complex design, which is significant for ease of integration with other nanostructures and fabrication at low cost. In this study, a planar plasmonic mirror without any nanoscale features is investigated that can focus surface plasmons to produce intense optical spots having lateral and vertical dimensions of λ/9.

Foamlike 3D Graphene Coatings for Cooling Systems Involving Phase Change.

Boiling is an efficient heat-transfer mechanism because of the utilization of latent heat of vaporization and has the potential to be used for cooling high-power electronic devices. Surface enhancement is one of the widely used techniques for heat-transfer augmentation in boiling systems. Here, an experimental investigation was conducted on chemical vapor deposition-grown three-dimensional (3D) foamlike graphene-coated silicon surfaces to investigate the effect of pore structures on pool boiling heat transfer and corresponding heat-transfer enhancement mechanisms.

Synthesis, Characterization, Electrochemical and Surface Morphologies of Polyazomethines Containing Silane and Phosphazene Units.

Polyazomethines containing silane and phosphazene groups were synthesized via elimination reactions of dihydroxy compounds containing imine bonding with phosphazane and silane dichloride. The structures of monomers and polymers containing phosphazane and silane groups were supported by H-NMR, C-NMR, FT-IR and UV-Vis techniques. Electrochemical properties of the prepared Schiff bases and polymers were given by cyclic voltammetric (CV) analysis.

Preparation and Characterization of poly(Azomethines) Containing Ether and Methylene Bridges: Photophysical, Electrochemical, Conductivity and Thermal Properties.

In this paper, a series of polyazomethines (PAZs) were prepared using dihydroxy substituted Schiff bases and 1,4-diiodobenzene. Also, different group effect such as methylene carbon and etheric oxygen bridges on photophysical, electrochemical, conductivity and thermal properties were clarified. The new polymeric materials structures were confirmed by means of H-NMR, FT-IR and UV-vis measurements.

Synthesis, Characterization, Electrical Conductivity and Fluorescence Properties of Polyimine Bearing Phenylacetylene Units.

In this study, a Schiff base was synthesized by the condensation reaction of 4-bromobenzaldehyde and 4-aminophenol. Then, phenylacetylene substituted Schiff base monomer (IPA) was obtained by HBr elimination reaction of IPA with phenylacetylene through Sonogashira reaction. IPA was polymerized via chemical oxidative polycondensation reaction.

Controlled growth of large area multilayer graphene on copper by chemical vapour deposition.

The growth of nearly full coverage of multilayer graphene on the surface of a 99.8% purity copper foil has been experimentally studied. It has been shown that the film thickness can be controlled by a single parameter, the growth time, and growth can be extended until nearly full coverage of more than one layer graphene over the copper surface.

2,4-Diamino-6-Hydroxypyrimidine Based Poly(azomethine-Urethane): Synthesis and Application as a Fluorescent Probe for Detection of Cu(2+) in Aqueous Solution.

A novel poly(azomethine-urethane)-based 2,4-diamino-6-hydroxyprimidine was synthesized with chemical reaction and it designed as fluorescence probe for determination of Cu(2+) in aqueous solution. The photoluminescence (PL) characteristic of the prepared Schiff base (HPAMP) and its poly(azomethine-urethane) (P-HPAMP) derivative were investigated in different polarity solvents suh as MeOH, THF and DMF. PL measurements showed that both HPAMP and P-HPAMP have higher emission intensity and Stoke's shift value (ΔλST) in THF than the other solvents.

Novel Multicolor Schiff Base Polymers Prepared via Oxidative Polycondensation.

A series of diimine Schiff bases and their polymers were synthesized via the oxidative polycondensation reaction. The structures of the compounds were confirmed by (1)H-NMR, (13)C-NMR, FT-IR and UV-vis spectral measurements. Electrochemical and optical band gap values of synthesized compounds were determined by cyclic voltammetry (CV) and UV-vis measurements, respectively.

Determination of thermodynamic properties of poly (cyclohexyl methacrylate) by inverse gas chromatography.

In this work, some thermodynamic properties of poly (cyclohexyl methacrylate) were studied by inverse gas chromatography (IGC). For this purpose, the polymeric substance was coated on Chromosorb W and which was filled into a glass column. The retention times (t(r)) of the probes were determined from the interactions of poly (cyclohexyl methacrylate) with n-pentane, n-hexane, n-heptane, n-octane, n-decane, methanol, ethanol, 2-propanol, butanol, acetone, ethyl methyl ketone, benzene, toluene and o-xylene by IGC technique.

Synthesis, characterization and non-isothermal decomposition kinetic of a new galactochloralose based polymer.

A glycopolymer, poly(3-O-methacroyl-5,6-O-isopropylidene-1,2-O-(S)-trichloroethylidene-α-d-galactofuranose) (PMIPTEG) was synthesized from the sugar-carrying methacrylate monomer, 3-O-methacroyl-5,6-O-isopropylidene-1,2-O-(S)-trichloroethylidene-α-d-galactofuranose (MIPTEG) via conventional free radical polymerization with AIBN in 1,4-dioxane. The structures of glycomonomer and their polymers were confirmed by UV-vis, FT-IR, (1)H NMR, (13)C NMR, GPC, TG/DTG-DTA, DSC, and SEM techniques. SEM images showed that PMIPTEG had a straight-chain length structure.

Note: Controlled fabrication of suspended metallic vacuum tunneling gaps.

We developed a new fabrication technique for the realization of nanogaps using conventional lithography and in situ controlled thermal evaporation. A 20-40 nm gap between two suspended metallic electrodes is shrunk down to about 1 nm using controlled thermal evaporation. It is demonstrated that with this technique rigid and stable metallic vacuum tunneling junctions can be consistently produced.

Highly selective and stable florescent sensor for Cd(II) based on poly (azomethine-urethane).

In this study a kind of poly(azomethine-urethane); (E)-4-((2 hydroxyphenylimino) methyl)-2-methoxyphenyl 6-acetamidohexylcarbamate (HDI-co-3-DHB-2-AP) was prepared as in the literature and employed as a new fluorescent probe for detection of Cd(II) concentration. The photoluminescence (PL) measurements were carried out in the presence of several kinds of heavy metals. HDI-co-3-DHB-2-AP gave a linearly and highly stable response against Cd(II) as decreasing a new emission peak at 562 nm.

Tuning of nanogap size in high tensile stress silicon nitride thin films.

High tensile stress suspended structures are demanded for high mechanical quality factor applications. However, high tensile stress causes distortion of the original shapes by contracting, buckling, and bending the suspended structures. We demonstrate a method to compensate for the shape deformation of suspended structures due to intrinsic tensile stress after they are released.

Syntheses and pH sensing applications of imine-coupled phenol and polyphenol species derived from 2-amino-4-nitrophenol.

Developing of new generation optical polymeric pH sensors has increasing importance due to their stable structures. Available polymeric sensors for different pH ranges are already needed. In the present study new kinds of monomeric and polymeric absorption pH sensors (HBANP and PHBANP) derived from 2-amino-4-nitrophenol were prepared.

Synthesis and spectrophotometric P(H) sensing applications of poly-2-[4-(diethylaminophenyl)imino]-5-nitro-phenol and its Schiff base monomer for two different P(H) ranges.

Poly-2-[4-(diethylaminophenyl)imino]-5-nitro-phenol (PEAPINP) and 2-[4-(diethylaminophenyl)imino]-5-nitro-phenol (EAPINP) were prepared as new pH sensors. Spectrophotometric and spectrofluorometric response of the novel sensors in various p(H) values were investigated. EAPINP has the ability to respond linearly at alkaline P(H) values, 8 to 9, and can be utilized in absorption and wavelength radiometric methods.

Biosynthesis and characterization of organosoluble conjugated poly(2-aminofluorene) with the pyrazine bridged.

In this paper, the results on horseradish peroxidase (HRP)-catalyzed oxidative polymerization of amine-functionalized fluorene monomer, 2-amino fluorene (AF), are reported. The resulting polymer exhibits an exciting molecular structure and spectral properties. FT-IR and NMR studies show that the two fluorene units come together by forming an intermediate six-membered pyrazine ring and these formed dimeric units are linked to the each other through C-C couplings to produce fully conjugated polymer structure (AFP).

Synthesis of a novel fluorescent Schiff base as a possible Cu(II) ion selective sensor.

In this study a new fluorescent Schiff base; 1,1'-(4,4'-oxybis(4,1-phenylene)bis(azan-1-yl-1-ylidene))bis(methan-1-yl-1-ylidene)dinaphthalen-2-ol (2-HNA) was synthesized and characterized by FT-IR, UV-vis, and (1)H and (13)C-NMR techniques. Photoluminescent properties of 2-HNA were investigated in different solvents including methanol, THF, DMF, DMSO, acetone, acetonitrile, and dichloromethane. 2-HNA was found to have higher emission intensity and Stoke's shift value (lambda(ST)) in methanol solution.