Transform Infrared (transform + infrared)

Distribution by Scientific Domains
Distribution within Polymers and Materials Science

Kinds of Transform Infrared

  • fourier transform infrared

  • Terms modified by Transform Infrared

  • transform infrared analysis
  • transform infrared spectrometry
  • transform infrared spectroscopy
  • transform infrared spectroscopy analysis
  • transform infrared spectrum

  • Selected Abstracts

    Laser local oxidation of porous silicon: a FTIR spectroscopy investigation

    M. Rocchia
    Abstract The local oxidation of porous silicon (PS), induced by a focused laser beam, could represent an alternative method for patterning PS through direct writing. Important phase changes take place on PS when irradiated by a focused laser beam and moreover a complete confinement of the oxidized areas can be achieved due to the very low thermal conductivity of PS. We present a detailed Fourier Transform InfraRed (FTIR) study of the irradiated areas to understand the degree of oxidation and the type of oxide obtained at different laser powers. An interpretation of the low wavenumber range, below 1300 cm,1, in terms of Fröhlich interactions will be discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Deposition of Barrier Layers for Thin Film Solar Cells Assisted by Bipolar Substrate Biasing

    Evelyn Häberle
    Abstract For the development of diffusion and insulation barriers for thin film solar cells on unpolished steel with a rough surface as substrate, investigations of the shape of deposited SiOx layers in dependence on an applied substrate biasing are carried out. Si-wafers with a well-defined surface structure in the range of micrometre are used as ,model' substrate. As a result, the deposition in the indentations of this surface is much higher in the case of a biased substrate. To determine the influence of the bias on the molecular structure, first investigations of the deposited layer without an applied bias are performed with in situ Fourier Transform InfraRed (FTIR) spectroscopy. Hence the molecular composition of the films is monitored during the deposition. In these spectra the Berreman effect occurs and is analysed. [source]

    Growth and properties of ferroelectric potassium ferrocyanide trihydrate single crystals

    R. Kanagadurai
    Abstract Single crystals of potassium ferrocyanide trihydrate, K4[Fe(CN)6·3H2O (KFCT), a ferroelectric material with Curie temperature 251K were grown in silica gel at room temperature for the first time by the solubility reduction method. Resorcinol and ethyl alcohol were used for the purpose of gel setting and supernatant liquid respectively. Optical and mechanical properties were studied for the grown crystal. The structure of the grown crystal was confirmed by X-ray diffraction analysis. Fourier Transform Infrared (FTIR) and FT Raman spectral analysis of the crystalline samples reveal that the crystalline sample consist consists of all functional groups. Thermal analysis of the crystalline sample was performed by TGA and DTA methods. The Vicker's micro hardness value was measured for KFCT crystals. The square etch pits with a hopper-like structure is an indicative of 2D nucleation mechanism. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Synthesis and characterization of potassium magnesium sulphate hexahydrate crystals

    M. Dhandapani
    Abstract Potassium magnesium sulphate hexahydrate (picromerite) was synthesized and single crystals were obtained from saturated aqueous solution by slow evaporation method at room temperature. The crystals were bright, colourless and transparent having well defined external faces. The grown crystals were characterized through Fourier Transform Infrared (FTIR) spectral studies and thermal analysis. The FTIR data were used to assign the characteristic vibrational frequencies of the various chemical bonds in the compound. The compound crystallizes in monoclinic lattice with the space group P21/c. The thermogravimetry (TG) indicates the removal of only two water molecules around 100 °C. A suitable decomposition pattern was formulated based on the percentage weight losses observed in TG of the compound. The results of differential thermal analysis (DTA) conform to the results of TGA. Differential scanning calorimetry (DSC) analysis carried out at high temperature suggests that the occurrence of two phase transitions in the crystal between 140 and 180 °C. When the crystal was cooled below the room temperature up to ,170 °C, no thermal anomaly was observed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Molecular imprinted solid-phase extraction of huperzine A from Huperzia Serrata

    Guosong Wang
    Abstract On the basis of the non-covalent interaction between template and monomer, porous molecularly imprinted polymers (MIPs) were synthesized by a thermal-initiated polymerization method using huperzine A as template, acrylamide, or methacrylic acid as function monomer, ethylene glycol dimethacrylate as cross-linking agent. The interaction between template and functional monomers was studied by UV spectrophotometry, which showed a formation of huperzine A-monomer complexes with stoichiometric ratio of 1 : 2 in the pre-polymerized systems. The resultant MIP particles were tested in the equilibrium binding experiment to analyze their adsorption ability to huperzine A, and were characterized by Fourier Transform Infrared (FTIR) study. The recognition properties of MIP were estimated in solid-phase extraction by selecting four compounds (isolated from the Chinese herb Huperzia serrata) as substrates, and were compared with and prior to those of the NIP. High affinity and adsorption of MIP1 which was prepared in chloroform with huperzine A as imprinted molecule, and acrylamide (AM) as functional monomer, made an attractive application of MIP1 in separation processes. In final, using MIP1 solid-phase extraction micro-column, huperzine A was enriched and separated from the real extraction sample of Huperzia serrata. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]

    Synthesis, cure kinetics, and thermal properties of the Bis(3-allyl-2-cyanatophenyl)sulphoxide/BMI blends

    G. Anuradha
    Abstract A novel allyl functionalized dicyanate ester resin bearing sulfoxide linkage was synthesized. The monomer was characterized by Fourier Transform Infrared (FT-IR) Spectroscopy, 1H-, and 13C Nuclear Magnetic Resonance (NMR) spectroscopy and elemental analysis. The monomer was blended with bismaleimide (BMI) at various ratios in the absence of catalyst. The cure kinetics of one of the blends was studied using differential scanning calorimetry [nonisothermal] and the kinetic parameters like activation energy (E), pre-exponential factor (A), and the order of the reaction (n) were calculated by Coats-Redfern method and compared with those calculated using the experimental Borchardt-Daniels method. The thermal stability of the cured dicyanate, BMI, and the blends was studied using thermogravimetric analyzer. The initial weight loss temperature of dicyanate ester is above 380°C with char yield of about 54% at 800°C. Thermal degradation of BMI starts above 463°C with the char yield of about 68%. Inclusion of BMI in cyanate ester increases the thermal stability from 419 to 441°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

    FT-IR spectroscopy in diagnosis of diabetes in rat animal model

    Feride Severcan
    Abstract In recent years, Fourier Transform Infrared (FT-IR) spectroscopy has had an increasingly important role in the field of pathology and diagnosis of disease states. In the current study, FT-IR spectroscopy together with cluster analysis were used as a diagnostic tool in the discrimination of diabetic samples from control ones in rat kidney plasma membrane apical sides (brush-border membranes), liver microsomal membranes and Extensor digitorum longus (EDL) and Soleus (SOL) skeletal muscle tissues. A variety of alterations in the spectral parameters, such as frequency and signal intensity/area was observed in diabetic tissues and membranes compared to the control samples. Based on these spectral variations, using cluster analysis successful differentiation between diabetic and control groups was obtained in different spectral regions. The results of this current study further revealed the power and sensitivity of FT-IR spectroscopy in precise and automated diagnosis of diabetes. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Detection of Sublethal Thermal Injury in Salmonella enterica Serotype Typhimurium and Listeria monocytogenes Using Fourier Transform Infrared (FT-IR) Spectroscopy (4000 to 600 cm,1)

    H.M. Al-Qadiri
    ABSTRACT:, Fourier transform infrared (FT-IR) spectroscopy (4000 to 600 cm,1) was utilized to detect sublethally heat-injured microorganisms: Salmonella enterica serotype Typhimurium ATCC 14028, a Gram-negative bacterium, and Listeria monocytogenes ATCC 19113, a Gram-positive bacterium. A range of heat treatments (N= 2) at 60 °C were evaluated: 0D (control), 2D, 4D, 6D, and 8D using a D60 °C (S. enterica serotype Typhimurium ATCC 14028 = 0.30 min, L. monocytogenes ATCC 19113 = 0.43 min). The mechanism of cell injury appeared to be different for Gram-negative and Gram-positive microbes as observed from differences in the 2nd derivative transformations and loadings plot of bacterial spectra following heat treatment. The loadings for PC1 and PC2 confirmed that the amide I and amide II bands were the major contribution to spectral variation, with relatively small contributions from C-H deformations, the antisymmetric P==O stretching modes of the phosphodiester nucleic acid backbone, and the C-O-C stretching modes of polysaccharides. Using soft independent modeling of class analogy (SIMCA), the extent of injury could be predicted correctly at least 83% of the time. Partial least squares (PLS) calibration analysis was constructed using 5 latent variables for predicting the bacterial counts for survivors of the different heat treatments and yielded a high correlation coefficient (R= 0.97 [S. enterica serotype Typhimurium] and 0.98 [L. monocytogenes]) and a standard error of prediction (SEP= 0.51 [S. enterica serotype Typhimurium] and 0.39 log10 CFU/mL [L. monocytogenes]), indicating that the degree of heat injury could be predicted. [source]

    Spectroscopic Differentiation and Quantification of Microorganisms in Apple Juice

    Chenxu Yu
    ABSTRACT: A fast and easy-to-operate Fourier Transform Infrared (FTIR) spectrometry-based approach was developed for microbial differentiation and quantification in apple juice. Eight different microorganisms were evaluated: Enterobacter cloacae, Salmonella typhimurium, Enterobacteraerogenes, Salmonella choleraesuis, Serratia marcescens, Pseudomonas vulgaris, Vibrio cholerae, and Hafnia alvei. FTIR spectroscopy combined with chemometrics could differentiate the microorganisms studied at low concentration level of 103 colony-forming units (CFU) /mL in apple juice. The chemometric models developed to count microorganisms in apple juice were validated by an independent test set consisting of 18 samples and correlated against plate counts satisfactorily up to a detection limit of 103 CFU/mL. [source]


    JOURNAL OF PHYCOLOGY, Issue 2 2001
    Mario Giordano
    Fourier Transform Infrared (FT-IR) spectroscopy was used to study carbon allocation patterns in response to changes in nitrogen availability in the diatom Chaetoceros muellerii Lemmerman. The results of the FT-IR measurements were compared with those obtained with traditional chemical methods. The data obtained with both FT-IR and chemical methods showed that nitrogen starvation led to the disappearance of the differences in cell constituents and growth rates existing between cells cultured at either high [NO3,] or high [NH4+]. Irrespective of the nitrogen source supplied before nitrogen starvation, a diversion of carbon away from protein, chlorophyll, and carbohydrates into lipids was observed. Under these conditions, cells that had previously received nitrogen as nitrate appeared to allocate a larger amount of mobilized carbon into lipids than cells that had been cultured in the presence of ammonia. All these changes were reversed by resupplying the cultures with nitrogen. The rate of protein accumulation in the N-replete cells was slower than the rate of decrease under nitrogen starvation. This study demonstrates that the relative proportions of the major macromolecules contained in microalgal cells and their changes in response to external stimuli can be determined rapidly, simultaneously, and inexpensively using FT-IR. The technique proved to be equally reliable to and less labor intensive than more traditional chemical methods. [source]

    Cathodic electrochemiluminescence of acetonitrile, acetonitrile,1,10-phenanthroline and acetonitrile,ternary Eu(III) complexes at a gold electrode

    Hong-Xiao Yu
    Abstract Cathodic electrochemiluminescence (ECL) behaviours of the acetonitrile, acetonitrile,1,10-phenanthroline (phen) and acetonitrile,ternary Eu(III) complex systems at a gold electrode were studied. One very weak cathodic ECL-2 at ,3.5 V was observed in 0.1 mol/L tetrabutylammonium tetrafluoroborate (TBABF4) acetonitrile solution. When 10 mmol/L tetrabutylammonium peroxydisulphate [(TBA)2S2O8] was added to 0.1 mol/L TBABF4 acetonitrile solution, another cathodic ECL-1 at ,2.7 V appeared and the potential for ECL-2 was shifted from ,3.5 to ,3.1 V. Furthermore, ECL-2 intensity was enhanced about 20-fold. When 1 × 10,4 mol/L phen was added to 0.1 mol/L TBABF4 + 10 mmol/L (TBA)2S2O8 acetonitrile solution, the ECL intensities of ECL-1 and ECL-2 were enhanced about 20-fold compared with those of 0.1 mol/L TBABF4 + 10 mmol/L (TBA)2S2O8 acetonitrile solution. The maximum emission peaks of ECL-1 and ECL-2 in the three systems mentioned above appeared at about 530 nm. The products obtained by electrolysing 0.1 mol/L TBABF4 acetonitrile solution at ,3.5 V for 20 min were analysed by Fourier Transform Infrared (FTIR) spectra and gas chromatography,mass spectrometry (GC,MS) and the emitter of ECL-1 and ECL-2 was identified as excited state polyacetonitrile. When ternary Eu(III) complexes were presented in 0.1 mol/L TBABF4 + 10 mmol/L (TBA)2S2O8 acetonitrile solution, another maximum emission peak with a narrow band centred at about 610 nm appeared in ECL-1 in addition to the maximum emission peaks at about 530 nm for ECL-1 and ECL-2. The emitter of ECL emission at 610 nm was identified as the excited states Eu(III)*. The mechanisms for cathodic ECL behaviours of the acetonitrile, acetonitrile,phen and acetonitrile,ternary Eu(III) complex systems at a gold electrode have been proposed. The extremely sharp emission bands for ternary Eu(III) complexes may have analytical potential. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Interface of atomic layer deposited Al2O3 on H-terminated silicon

    K. Y. Gao
    Abstract Al2O3 films 1 to 20 nm thick were deposited as alternative high-, gate dielectric on hydrogen-terminated silicon by Atomic Layer Deposition (ALD) and characterized by Synchrotron X-ray Photoelectron Spec-troscopy (SXPS), Fourier Transform Infrared (FTIR) absorption spectroscopy and admittance measure-ments. The SXPS results indicate that about 60% of the original Si,H surface bonds are preserved at the Al2O3/Si interface and this is confirmed by monitoring the Si,H stretching modes by FTIR spectroscopy in the Attenuated Total Reflection (ATR) mode both before and after ALD of Al2O3. The remaining 40% of Si,H bonds are replaced by Si,O bonds as verified by SXPS. In addition, a fraction of a monolayer of SiO2 forms on top of the Al2O3 dielectric during deposition. The presence of OH-groups at a level of 3% of the total oxygen content was detected throughout the Al2O3 layer through a chemically shifted O 1s component in SXPS. Admittance measurements give a dielectric constant of 9.12, but a relatively high density of interface traps between 1011 and 1012 cm,2 eV,1. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Deposition of Plasma-Polymerized 1-Cyanoisoquinoline Thin Films and Their Dielectric Properties

    Xiong-Yan Zhao
    Abstract A novel plasma-polymerized 1-cyanoisoquinoline (PPCIQ) thin film of desired thickness was prepared by plasma polymerization under different glow discharge conditions. The effect of the discharge power on the chemical structure, surface composition and morphology of the PPCIQ thin films were investigated by Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and deposition rate measurements. A high retention of the aromatic ring structure of the starting monomer in the deposited plasma films is obtained at a low discharge power of 15 W. The plasma-synthesized films are homogeneous and quite suitable for the measurement of dielectric properties. The dielectric measurements show that a low dielectric constant of 2.62 has been obtained for the PPCIQ thin films for the first time. [source]

    In situ generated diphenylsiloxane-polyimide adduct-based nanocomposites

    Manisha G. Goswami
    Arylsiloxane was incorporated into polyimide (PI) via electronic interaction with polyamic acid (PAA)/PI, and a wide spectrum of properties were evaluated for different compositions. The samples prepared with relatively low concentrations (0.0001,0.1%) of oligomers showed unusual synergism, which is attributed to the generation of nanostructures dispersed in the continuous PI matrix. The incorporation of siloxane with bulky phenyl groups contributed to enhanced thermal stability as determined by thermogravimetric analysis. Water uptake and methanol absorption by these composites were evaluated and correlated with the underlying micro- and nanostructures. Fourier Transform Infrared (FTIR) spectroscopy was used to elucidate the probable reaction mechanism (including in situ polymerization of arylsilanol), and to study the synthetic aspects associated with the molecular composites and nanocomposites formation. POLYM. ENG. SCI., 45:142,152, 2005. © 2004 Society of Plastics Engineers [source]

    Molecular interactions of isoxazolcurcumin with human serum albumin: Spectroscopic and molecular modeling studies

    BIOPOLYMERS, Issue 2 2009
    Bijaya Ketan Sahoo
    Abstract Curcumin is a nontoxic natural product with diverse pharmacological potencies. We report the interaction of a potent synthetic derivative of curcumin, isoxazolcurcumin (IOC) with human serum albumin (HSA) using various biophysical methods. The observed fluorescence quenching of HSA by IOC is due to a complex formation by a static quenching process with a quenching constant of the order of 105M,1. The binding affinity and the number of binding sites were obtained from a Scatchard analysis. Thermodynamics reveals that the interaction is entropy driven with predominantly hydrophobic forces. From the observed Förster-type fluorescence resonance energy transfer (FRET), the donor (Trp 214 in HSA) to acceptor (IOC) distance is calculated to be 3.2 nm. The conformational changes of HSA due to the interaction were investigated qualitatively from synchronous fluorescence spectra along with a quantitative estimation of the secondary structure from Fourier Transform Infrared (FTIR) and circular dichroism (CD) spectroscopies. Molecular docking studies were performed to obtain information on the possible residues involved in the interaction process, and changes in accessible surface area of the interacting residues were calculated. The preferred binding site of IOC was analyzed by ligand displacement experiments with 1-anilino-8-naphthalenesulfonate (ANS) and warfarin-bound HSA. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 108,119, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at [source]

    Comparison of FTIR, FT-Raman, and NIR Spectroscopy in a Maple Syrup Adulteration Study

    M. M. Paradkar
    ABSTRACT: Maple syrup is prone to adulteration with cheaper sugars, such as corn syrup, due to its simplicity in chemical composition. The adulterated samples were characterized by Fourier Transform infrared (FTIR) spectroscopy in the region of 400 to 4000 cm -1. Other techniques used for detection and in characterization of samples were the near infrared (NIR; 600 to 1700nm) and Fourier Transform-Raman (FT-Raman; 400 to 4000cm -1) spectroscopy. Quantifying and classifying adulterants using chemometrics shows that all spectroscopic methods adopted were efficient, but FTIR and FT-Raman were superior to NIR in quantitative characterization of adulterants in maple syrup. [source]

    FT-IR Investigation into the miscible interactions in new materials for optical devices

    Lakshmi Sharma
    Abstract In this article we determine the miscibility of azobenzene derivative (poly(4-(N-(2-methacryloyloxyethyl)-N-ethylamino)-4,-nitroazobenzene)90 -co-(methyl methacrylate)10)/poly(vinyl acetate) (PVAc) and azobenzene derivative/poly(vinyl chloride) (PVC) blends using Fourier Transform infrared (FT-IR) spectroscopy. With this method we can clearly identify the exact interactions responsible for miscibility. In the azobenzene derivative 50:50PVAc blend new peaks were evident at 2960, 2890, 1237 and 959,cm,1, these peaks depict miscible interactions. These wavenumbers indicate that the miscible interactions occurring are from the CH stretching band, the vinyl acetate CO, conjugated to the ester carbonyl, the cis-transformation NN stretch frequency and the acetate ester weak doublet. The azobenzene derivative 80:20PVC blend display peaks identical in profile to the blend homopolymers, indicating no miscible interactions. However, this could be due to overlapping of peaks within the same wavenumber region, making resolution difficult. This research demonstrates FT-IR can deduce favorable interactions for miscibility and therefore numerous miscible blends can successfully be calculated if possessing the same groups responsible for miscibility. This paves the way for a new generation of designer optical materials with the desired properties. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    Effects of Polymer Architecture and Composition on the Adhesion of Poly(tetrafluoroethylene)

    CHEMPHYSCHEM, Issue 6 2006
    Chen-Yuan Tu Dr.
    Abstract Poly(glycidyl methacrylate), PGMA, chains in linear and arborescent structures were incorporated onto surfaces of poly(tetrafluoroethylene), PTFE, films by hydrogen plasma and ozone treatment and atom transfer radical polymerization. The epoxide groups of the PGMA chains were further reacted with acetic acid (AAc), oxalic acid (XAc), allyl amine (AA), and ethylenediamine (EDN) to introduce hydroxyl and amine groups to the surfaces of the PTFE films. Surface characterizations performed by Fourier Transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the surface modification and the chemical structure. The PGMA chains in arborescent structures show a high effectiveness for the enhancement of the adhesion of PTFE films. The adhesion of PTFE films was also significantly enhanced by ring-opening reactions of the PGMA epoxide groups with acetic acid and amine compounds. A high value of 9.5 N,cm,1 in the optimum 180° peel strength test was observed with PTFE/copper assemblies. [source]

    Study of pseudo-multilayer structures based on starch-polycaprolactone extruded blends

    Laurent Bélard
    This article is focused on the analysis of the structure-process relationships of biodegradable materials. It is mainly focused on the analysis of phase separation phenomenon occurring during the extrusion of plasticized starch/polycaprolactone blends, in a slit die. Rheological characterizations are carried out, in-line in an instrumented slit die at the exit of the extruder and, out-line with different rheometers. In certain conditions, a pseudo-multilayer structure can be generated with a polyester rich skin. Then, Electron Spectroscopy for Chemical Analysis (ESCA) and Fourier Transformed Infrared Attenuated Total Reflectance (FTIR-ATR) analyses are conducted to evaluate semi-quantitatively the polyester surface enrichment. In the range of available shear rates, the phase separation is mainly driven by the molecular weight of polycaprolactone, linked to its molten state viscosity. Three zones of surface enrichment, dependent on the molecular weights, are identified. Above 60,000 g·mol,1, no surface enrichment could be detected; below 37,000 g·mol,1, the phase separation occurs with no dependence on the processing conditions; between these two limits, the phase separation depends on both, the formulation and the processing conditions. A correlation between the rheological measurements and the phase separation is given. A predictive criterion based on the viscous behavior of the blend is established. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source]

    Synthesis and characterization of fine lithium niobate powders by sol- gel method

    L. H. Wang
    Abstract Lithium niobate (LN) nanocrystal powders were prepared by low-temperature sol-gel method. Dihydrate lithium acetate as lithium source, and niobium chloride as niobium source were used as starting materials. The gel and powders were characterized by thermogravimetry and differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), transmission electronmicroscopy (TEM) and Fourier transform infrared (FTIR) spectra. The results show that when the gel was heat-treated at 600°C, the fine LN nanocrystals with the size of 40-60 nm were obtained, and the size of the powders become larger with the heat-treated temperature increasing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Gel growth and characterization of , -DL-methionine

    E. Ramachandran
    Abstract DL-Methionine [C5H11NO2S] is one of the essential amino acids in humans. It has two crystalline forms, viz., ,- and ,- methionine. In the present study, , - form is crystallized in silica gel; under suitable pH conditions by single diffusion method. The grown crystals were characterized by density measurement and single crystal X-ray diffraction. Fourier transform infrared (FTIR) spectroscopic studies, thermal analysis and scanning electron microscopic (SEM) studies were also made as part of the structural studies. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    A New Amperometric Hydrazine Sensor Based on Prussian Blue/Single-walled Carbon Nanotube Nanocomposites

    ELECTROANALYSIS, Issue 16 2010
    Cong Wang
    Abstract A slow reaction process has been successfully used to synthesize Prussian blue/single-walled carbon nanotubes (PB/SWNTs) nanocomposites. Electrochemical and surface characterization by cyclic voltammetry (CV), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed the presence of PB nanocrystallites on SWNTs. PB/SWNTs modified glassy carbon electrode (GCE) exhibits efficient electron transfer ability and high electrochemical response towards hydrazine. The fabricated hydrazine sensor showed a wide linear range of 2.0×10,6,6.0×10,3,M with a response time less than 4,s and a detection limit of 0.5,,M. PB/SWNTs modified electrochemical sensors are promising candidates for cost-effective in the hydrazine assays. [source]

    Dentin surface treatment using a non-thermal argon plasma brush for interfacial bonding improvement in composite restoration

    Andy C. Ritts
    Ritts AC, Li H, Yu Q, Xu C, Yao X, Hong L, Wang Y. Dentin surface treatment using a non-thermal argon plasma brush for interfacial bonding improvement in composite restoration. Eur J Oral Sci 2010; 118: 510,516. © 2010 Eur J Oral Sci The objective of this study was to investigate the treatment effects of non-thermal atmospheric gas plasmas on dentin surfaces used for composite restoration. Extracted unerupted human third molars were prepared by removing the crowns and etching the exposed dentin surfaces with 35% phosphoric acid gel. The dentin surfaces were treated using a non-thermal atmospheric argon plasma brush for various periods of time. The molecular changes of the dentin surfaces were analyzed using Fourier transform infrared spectrophotometry/attenuated total reflectance (FTIR/ATR), and an increase in the amount of carbonyl groups was detected on plasma-treated dentin surfaces. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were applied as directed. To evaluate the dentin/composite interfacial bonding, the teeth thus prepared were sectioned into micro-bars and analyzed using tensile testing. Student,Newman,Keuls tests showed that the bonding strength of the composite restoration to peripheral dentin was significantly increased (by 64%) after 30 s of plasma treatment. However, the bonding strength to plasma-treated inner dentin did not show any improvement. It was found that plasma treatment of the peripheral dentin surface for up to 100 s resulted in an increase in the interfacial bonding strength, while prolonged plasma treatment of dentin surfaces (e.g. 5 min) resulted in a decrease in the interfacial bonding strength. [source]

    Interactions of ferricyanide with humic soils and charred straw

    T. Rennert
    Summary The iron-cyanide complexes ferricyanide, [FeIII(CN)6]3,, and ferrocyanide, [FeII(CN)6]4,, are anthropogenic contaminants in soil. We studied the interactions of ferricyanide with humic soils and charred straw (maize and rye, both charred at 300, 400 and 500°C) by batch experiments and Fourier transform infrared (FTIR) spectroscopy. All soil samples sorbed ferricyanide (up to 8.4 g kg,1). Precipitation of a manganese ferrocyanide after reduction of ferricyanide in the moderately acidic to neutral soils was deduced from both FTIR spectroscopy (CN absorption bands at 2069,2065 cm,1) and geochemical modelling. Ferricyanide was also adsorbed onto the charred straw. The amounts of iron-cyanide complexes adsorbed increased with increasing charring temperature, with a maximum of 1.71 g kg,1. An absorption band at 2083 cm,1 indicated weakly adsorbed intermediates of the reduction of ferricyanide to ferrocyanide. This band disappeared in the samples charred at higher temperature, whereas a band at 2026 cm,1 was present in all spectra and became intensified in the high-temperature straw. We attribute this band to ferrocyanide forming inner-sphere complexes, presumably with quinone species of the organic matter. The band at 2026 cm,1 was also present in the spectra of the soils, indicating that soil organic matter also adsorbs ferrocyanide. However, in humic soils the main processes of ferricyanide interaction include reduction to ferrocyanide and precipitation as manganese ferrocyanide. Quantitatively, adsorption on highly aromatic substances plays only a less important role as compared with precipitation. [source]

    Characterizing organic matter of soil aggregate coatings and biopores by Fourier transform infrared spectroscopy

    R. H. Ellerbrock
    Summary In some soils, aggregate coatings and walls of biopores differ in the content of clay and organic carbon from that of the aggregate interiors or the soil matrix. The composition of the organic matter on aggregates and on the surfaces of biopores is largely unknown. We have compared the composition of organic matter between inner and outer parts of aggregates and between biopore walls and the soil matrix in a loamy arable soil and a sandy forest one. Hot-water- and sodium-pyrophosphate-extractable organic matter was analysed by Fourier transform infrared (FT-IR) spectroscopy. For the sandy forest soil, the FT-IR spectra showed that organic matter from the walls of root channels contains fewer functional groups with absorption bands at 1740,1710 cm,1 and 1640,1600 cm,1 than that from burrow fillings. For the arable soil, the content of these functional groups in hot-water-soluble organic matter from the coatings is less than in that from the interiors in the topsoil, and the reverse is so in the subsoil, probably because water-soluble organic matter containing these functional groups has moved from topsoil to subsoil. The results indicate that root channels in the forest soil have more reactive zones in an otherwise relatively inert sandy matrix, whereas aggregate coatings in the arable subsoil have a greater cation exchange capacity and a greater sorption potential for hydrophobic substances than the aggregate interiors. [source]

    Flame retardation and thermal degradation of flame-retarded polypropylene composites containing melamine phosphate and pentaerythritol phosphate

    FIRE AND MATERIALS, Issue 5 2008
    Shun Zhou
    Abstract The flame retardation of polypropylene (PP) composites containing melamine phosphate (MP) and pentaerythritol phosphate (PEPA) was characterized by limiting oxygen index (LOI) and UL 94. The morphology of the char obtained from the combustion of the composites was studied by scanning electron microscopy (SEM). The thermal degradation of the composites was investigated using thermogravimetric (TG) analysis and real-time Fourier transform infrared (RTFTIR) spectroscopy. It has been found that the PP composites containing only MP do not show good flame retardancy even at 40% additive level. Compared with the PP/MP binary composites, all the LOI values of the PP/MP/PEPA ternary composites at the same additive loading increase, and UL 94 ratings of the ternary composites at suitable MP/PEPA ratios are raised to V-0 from no rating (PP/MP). The TG and RTFTIR studies indicate that the interaction occurs among MP, PEPA and PP. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    FT-IR measurements of petroleum fluid inclusions: methane, n -alkanes and carbon dioxide quantitative analysis

    GEOFLUIDS (ELECTRONIC), Issue 1 2001
    J. Pironon
    Abstract A recent advancement in petroleum geochemistry is to model fossil oil composition using microthermometric and volumetric data acquired from individual fluid inclusion analysis. Fourier transform infrared (FT-IR) microspectroscopy can record compositional information related to gas (CH4 and CO2) and alkane contents of petroleum inclusions. In this study, a quantitative procedure for FT-IR microspectrometry has been developed to obtain, from individual fluid inclusions, mol percentage concentrations of methane, alkanes and carbon dioxide as constraints to thermodynamic modelling. A petroleum inclusion in a sample from the Québec City Promontory nappe area was used as standard to record a reference spectrum of methane. The analytical procedure is based on the measurement of CH4/alkane and CH4/CO2 band area ratios. CH4/alkane infrared band area ratio is obtained after spectral subtraction of the reference methane spectrum. This area ratio, affected by absolute absorption intensities of methane, methyl and methylene, provides a molar CH4/alkane ratio. Methyl/methylene ratio (CH2/CH3) ratio is obtained following procedures established in previous work. CO2/CH4 concentration ratio is estimated from relative absolute absorption intensities. Application to natural inclusions from different environments shows good correlation between FT-IR quantification and PIT (petroleum inclusion thermodynamic) modelling. [source]

    Preparation of Protamine,Titania Microcapsules Through Synergy Between Layer-by-Layer Assembly and Biomimetic Mineralization

    Yanjun Jiang
    Abstract A novel approach combining layer-by-layer (LbL) assembly with biomimetic mineralization is proposed to prepare protamine,titiania hybrid microcapsules. More specifically, these microcapsules are fabricated by alternative deposition of positively charged protamine layers and negatively charged titania layers on the surface of CaCO3 microparticles, followed by dissolution of the CaCO3 microparticles using EDTA. During the deposition process, the protamine layer induces the hydrolysis and condensation of a titania precursor, to form the titania layer. Thereafter, the negatively charged titania layer allows a new cycle of deposition step of the protamine layer, which ensures a continuous LbL process. The morphology, structure, and chemical composition of the microcapsules are characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy. Moreover, these protamine,titania hybrid microcapsules are first employed as the carrier for the immobilization of yeast alcohol dehydrogenase (YADH), and the encapsulated YADH displays enhanced recycling stability. This approach may open a facile, general, and efficient way to prepare organic,inorganic hybrid materials with different compositions and shapes. [source]

    The Influence of UV Irradiation on Ketonic Defect Emission in Fluorene-Based Copolymers,

    Horst Scheiber
    Abstract The influence of UV irradiation in inert atmosphere on the emission spectrum of fluorenone containing poly[9,9-bis(2-ethyl)hexylfluorene] (PF2/6) has been investigated by means of optical absorption, photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopy. It is shown that a substantial reduction of green emission arising from ketonic defect sites can be achieved by irradiation of thin films with UV light. This is found to be accompanied by partial cross-linking of the films. FTIR measurements show no reduction of the C=O stretching mode upon irradiation, and, moreover, the degree of cross-linking does not scale with the relative fluorenone content (0.1, 0.5, and 5%). Therefore, the reduced emission intensity in the green spectral region is rather associated with the occurrence of interruptions in the polymer backbone, which reduce the effective conjugation length and subsequently inhibit the energy transfer onto the ketonic defect sites. The found results enabled us to build organic light emitting devices (OLEDs) that can be structured by selective illumination of the emitting layer with an intense UV light source. This method allows for the fabrication of rather efficient (2000,cd,m,2 at 7,V) two-color OLEDs. [source]

    Formation of Oxynitride as the Photocatalytic Enhancing Site in Nitrogen-Doped Titania Nanocatalysts: Comparison to a Commercial Nanopowder,

    X. Chen
    Abstract A nitrogen-doped TiO2 nanocolloid has been successfully prepared and its properties compared with the commercially available TiO2 nanomaterial, Degussa P25. Several characterization techniques, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, Raman scattering, and UV-visible reflectance spectra, are combined in order to determine the crystal phase and grain size, shape, degree of nitrogen incorporation, and nature of the resultant oxynitride chemical bonding on the surface and in the bulk. The high relative photocatalytic activity of the nitrogen doped-TiO2 nanocolloid is evaluated through a study of the decomposition of methylene blue under visible light excitation. The ease and degree of substitutional-insertional nitrogen doping is held accountable for the significant increase in photocatalytic activity in the porous nanocolloid versus the nitrided commercial nanopowder. It is suggested that the nitrogen incorporation produces an NO bonding region as evidenced by the resulting XPS spectrum. [source]