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Sample records for acid complex films

  1. Structural organization of films based on polyaniline/polysulfonic acid complexes depending on the synthesis method

    The optical properties and morphology of complexes based on polyaniline (PANI) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), depending on their synthesis conditions, have been characterized by UV-visible spectroscopy and atomic force microscopy. The dependence of the electron absorption spectra of PANI/PAMPS complexes and the surface topography of their films on the initiation way of PANI formation (chemical and enzymatic) and the use of promoters of aniline polymerization has been investigated. The aniline polymerization kinetics with and without polymerization promoters has been studied. All PANI/PAMPS complexes are found to have a nanocomposite time-stable structure.

  2. Improvement of the photo stabilization of PVC films in the presence of thioacetic acid benzothiazole complexes

    The photo stabilization of poly(vinyl chloride) (PVC) films by 2-thioacetic acid benzothiazole with Sn (II), Cd (II), Ni (II), Zn (II) and Cu (II) complexes was investigated. The PVC films containing concentration of complexes 0.5 % by weight were produced by the same casting method from tetrahydrofuran (THF) solvent. The photo stabilization activities of these compounds were determined by monitoring the carbonyl, polyene and hydroxyl indices with irradiation time. The changes in viscosity average molecular weight of PVC with irradiation time were also tracked (using THF as a solvent). The quantum yield of the chain scission (φcs) of these complexes in PVC films was evaluated and found to range between 4.71 x 10-8 and 8.98 x 10-8. Results obtained showed that the rate of photo stabilization of PVC in the presence of the additive follows the trend: Sn(L)2 > Cd(L)2 > Ni(L)2 > Zn(L)2 > Cu(L)2. According to the experimental results obtained, several mechanisms were suggested depending on the structure of the additive. Among them HCl scavenging, UV absorption, peroxide decomposer and radical scavenger for photo stabilizer additives mechanisms were suggested. (author)

  3. Optical characterization and blu-ray recording properties of metal(II) azo barbituric acid complex films

    Smooth thin films of nickel(II), cobalt(II) and zinc(II) complexes with azo barbituric acid were prepared by the spin-coating method. Absorption spectra of the thin films on K9 glass substrates in 300-700 nm wavelength region were measured. Optical constants (complex refractive index N = n + ik) of the thin films prepared on single-crystal silicon substrates in 275-695 nm wavelength region were investigated on rotating analyzer-polarizer type of scanning ellipsometer, and dielectric constant ε (ε = ε1 + iε2) as well as absorption coefficient α of thin films were calculated at 405 nm. In addition, static optical recording properties of the cobalt(II) complex thin film with an Ag reflective layer was carried out using a 406.7 nm blue-violet laser and a high numerical aperture (NA) of 0.90. Clear recording marks with high reflectivity contrast (>60%) at proper laser power and pulse width were obtained, and the size of recording mark was as small as 250 nm. The results indicate that these metal(II) complexes are promising organic recording medium for the blu-ray optical storage system

  4. Optical characterization and blu-ray recording properties of metal(II) azo barbituric acid complex films

    Li, X.Y. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)], E-mail: xyli@siom.ac.cn; Wu, Y.Q. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Lab of Functional Inorganic Material Chemistry (Heilongjiang University), Ministry of Education, Haerbin 150080 (China)], E-mail: yqwu@siom.ac.cn; Gu, D.D.; Gan, F.X. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2009-02-25

    Smooth thin films of nickel(II), cobalt(II) and zinc(II) complexes with azo barbituric acid were prepared by the spin-coating method. Absorption spectra of the thin films on K9 glass substrates in 300-700 nm wavelength region were measured. Optical constants (complex refractive index N = n + ik) of the thin films prepared on single-crystal silicon substrates in 275-695 nm wavelength region were investigated on rotating analyzer-polarizer type of scanning ellipsometer, and dielectric constant {epsilon} ({epsilon} = {epsilon}{sub 1} + i{epsilon}{sub 2}) as well as absorption coefficient {alpha} of thin films were calculated at 405 nm. In addition, static optical recording properties of the cobalt(II) complex thin film with an Ag reflective layer was carried out using a 406.7 nm blue-violet laser and a high numerical aperture (NA) of 0.90. Clear recording marks with high reflectivity contrast (>60%) at proper laser power and pulse width were obtained, and the size of recording mark was as small as 250 nm. The results indicate that these metal(II) complexes are promising organic recording medium for the blu-ray optical storage system.

  5. Study of iron (III) complexed with radiation grafted acrylic acid onto poly (tetrafluoroethylene-Co-perfluoro vinyl ether) films

    To introduce functional moieties to a poly (tetrafluoroethylene-Co-perfluoro vinyl ether) film (PFA) graft copolymerization of vinyl monomer such as acrylic acid (AAc) was attempted by a simultaneous technique in aqueous solution using γ-irradiation. The graft copolymer was complexed with the Fe (III) in aqueous solution. The grafted copolymer-metal complexes were examined by infrared (IR), ultraviolet (UV), energy-dispersive X-ray (EDX) and electron spin resonance (ESR) techniques. The effect of temperature on the trunk copolymer, untreated grafted and treated grafted copolymer films was examined by IR and thermogravimetric analysis (TGA). The overall results suggest octahedral environment for Fe (III) and revealed the high ability of the obtained ligand-metal complexes. Furthermore, scanning electron microscope (SEM) investigation of the grafted and modified films, both unheated and heated (200 degree C) showed changes in the structure and surface morphology. It was found that the modified grafted membranes may make them promising for some practical applications such as the recovery of metal from aqueous systems

  6. Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities

    A. L. Van Wyngarden

    2014-11-01

    Full Text Available Particles in the upper troposphere and lower stratosphere (UT/LS consist mostly of concentrated sulfuric acid (40–80 wt % in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric aerosols and are potentially more important at the high acidities characteristic of UT/LS particles. In this study, experiments combining sulfuric acid (H2SO4 with propanal and with mixtures of propanal with glyoxal and/or methylglyoxal at acidities typical of UT/LS aerosols produced highly colored surface films (and solutions that may have implications for aerosol properties. In order to identify the chemical processes responsible for the formation of the surface films, Attenuated Total Reflectance–Fourier Transform Infrared and 1H Nuclear Magnetic Resonance spectroscopies were used to analyze the chemical composition of the films. Films formed from propanal were a complex mixture of aldol condensation products, acetals and propanal itself. The major aldol condensation products were the dimer (2-methyl-2-pentenal and 1,3,5-trimethylbenzene, which was formed by cyclization of the linear aldol condensation trimer. Additionally, the strong visible absorption of the films indicates that higher order aldol condensation products must also be present as minor species. The major acetal species were 2,4,6-triethyl-1,3,5-trioxane and longer-chain linear polyacetals which are likely to separate from the aqueous phase. Films formed on mixtures of propanal with glyoxal and/or methylglyoxal also showed evidence for products of cross-reactions. Since cross-reactions would be more likely than self-reactions under atmospheric conditions, similar reactions of aldehydes like propanal with common aerosol organic species like glyoxal

  7. Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities

    Van Wyngarden, A. L.; Pérez-Montaño, S.; Bui, J. V. H.; Li, E. S. W.; Nelson, T. E.; Ha, K. T.; Leong, L.; Iraci, L. T.

    2015-04-01

    Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40-80 wt%) in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric aerosols and are potentially more important at the high acidities characteristic of UT/LS particles. In this study, experiments combining sulfuric acid (H2SO4) with propanal and with mixtures of propanal with glyoxal and/or methylglyoxal at acidities typical of UT/LS aerosols produced highly colored surface films (and solutions) that may have implications for aerosol properties. In order to identify the chemical processes responsible for the formation of the surface films, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and 1H nuclear magnetic resonance (NMR) spectroscopies were used to analyze the chemical composition of the films. Films formed from propanal were a complex mixture of aldol condensation products, acetals and propanal itself. The major aldol condensation products were the dimer (2-methyl-2-pentenal) and 1,3,5-trimethylbenzene that was formed by cyclization of the linear aldol condensation trimer. Additionally, the strong visible absorption of the films indicates that higher-order aldol condensation products must also be present as minor species. The major acetal species were 2,4,6-triethyl-1,3,5-trioxane and longer-chain linear polyacetals which are likely to separate from the aqueous phase. Films formed on mixtures of propanal with glyoxal and/or methylglyoxal also showed evidence of products of cross-reactions. Since cross-reactions would be more likely than self-reactions under atmospheric conditions, similar reactions of aldehydes like propanal with common aerosol organic species like glyoxal and

  8. A solid-state sensor based on ruthenium (II) complex immobilized on polytyramine film for the simultaneous determination of dopamine, ascorbic acid and uric acid

    Khudaish, Emad A., E-mail: ejoudi@squ.edu.om [Sultan Qaboos University, College of Science, Chemistry Department, PO Box 36, PC 123 Muscat (Oman); Al-Ajmi, Khawla Y. [Sultan Qaboos University, College of Science, Chemistry Department, PO Box 36, PC 123 Muscat (Oman); Al-Harthi, Salim H. [Sultan Qaboos University, College of Science, Department of Physics, PO Box 36, PC 123 Muscat (Oman)

    2014-08-01

    A solid-state sensor based on a polytyramine (Pty) film deposited on a glassy carbon electrode doped with a tris(2,2′-bipyridyl)Ru(II) complex (Ru/Pty/GCE) was constructed electrochemically. The surface morphology of the film modified electrode was characterized using electrochemical and surface scanning techniques. A redox property represented by a [Ru(bpy){sub 3}]{sup 3+/2+} couple immobilized at the Pty moiety was characterized using typical voltammetric techniques. A distinct Ru 3d peak obtained at 280.9 eV confirms doping of the Ru species onto the Pty moiety characterized by X-ray photoelectron (XPS). Atomic force microscopy (AFM) images demonstrate that incorporation of Ru decreases the surface roughness of the native Pty film modified electrode. The Ru/Pty/GCE exhibits efficient electrochemical sensing toward the oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) in their mixture. Three well-defined peaks were resolved with a large peak to peak separation and the detection limits of AA, DA and UA are brought down to 0.31, 0.08 and 0.58 μM, respectively. Interference studies and application for DA determination in real samples were conducted with satisfactory results. - Highlights: • XPS data confirm doping of ruthenium onto the polytyramine moiety. • The voltammetric signals of ascorbic acid, dopamine and uric acid are well defined. • The sensor is stable and offers a large adsorption facility for all species. • The sensor is highly sensitive to dopamine oxidation. • The sensor is applied to a real sample with a satisfactory recovery percentage.

  9. A solid-state sensor based on ruthenium (II) complex immobilized on polytyramine film for the simultaneous determination of dopamine, ascorbic acid and uric acid

    A solid-state sensor based on a polytyramine (Pty) film deposited on a glassy carbon electrode doped with a tris(2,2′-bipyridyl)Ru(II) complex (Ru/Pty/GCE) was constructed electrochemically. The surface morphology of the film modified electrode was characterized using electrochemical and surface scanning techniques. A redox property represented by a [Ru(bpy)3]3+/2+ couple immobilized at the Pty moiety was characterized using typical voltammetric techniques. A distinct Ru 3d peak obtained at 280.9 eV confirms doping of the Ru species onto the Pty moiety characterized by X-ray photoelectron (XPS). Atomic force microscopy (AFM) images demonstrate that incorporation of Ru decreases the surface roughness of the native Pty film modified electrode. The Ru/Pty/GCE exhibits efficient electrochemical sensing toward the oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) in their mixture. Three well-defined peaks were resolved with a large peak to peak separation and the detection limits of AA, DA and UA are brought down to 0.31, 0.08 and 0.58 μM, respectively. Interference studies and application for DA determination in real samples were conducted with satisfactory results. - Highlights: • XPS data confirm doping of ruthenium onto the polytyramine moiety. • The voltammetric signals of ascorbic acid, dopamine and uric acid are well defined. • The sensor is stable and offers a large adsorption facility for all species. • The sensor is highly sensitive to dopamine oxidation. • The sensor is applied to a real sample with a satisfactory recovery percentage

  10. The effect of dual complexing agents of lactic and citric acids on the formation of sol-gel derived Ag–PbTiO3 percolative thin film

    Controlling the formation of conductive particles to be nano-scale is important for achieving percolation effect in metal dispersed thin film composite to contribute extraordinary dielectric properties required for miniaturization of electronic devices. In this paper, lactic acid (LA) and citric acid (CA) were used as dual complexing agents to prepare a typical Ag nanoparticle dispersed PbTiO3 (PTO) composite thin film by using a sol-gel method. The phase structure of the thin film and the coordination effect between complexing agent and metallic ions were investigated. It revealed that LA coordinated with Ti4+ and Pb2+ and CA coordinated with Ag+. Lead was fixed inside the gel network by LA and restricted to evaporate during heat treatment thus the pyrochlore phase was prevented from forming in the thin film. Ag+ was coordinated by CA and the diffusion and thus aggregation of silver during gelation and annealing process were weakened. Silver nanoparticles dispersed in the PTO matrix formed with dual complexing agents of LA and CA introduced during the preparation process. The composite thin film of perfect perovskite phase with silver nanoparticles embedded was obtained at the molar ratio of LA/lead = 0.5 and CA/lead = 0.5. The dielectric constant of the thin film with silver nanoparticles is 5 times higher than that without silver nanoparticles. - Highlights: • Ag nanoparticle–PbTiO3 percolative film with high dielectric property is prepared. • Evaporation of lead was prevented by coordinating Pb with lactic acid agent. • Dual complexing agents contribute block and pinning effects to form Ag nanoparticles

  11. Self-assembly and photoelectric properties of cerium complexes with 3,4,9,10-perylenetetracarboxylic acid on nanocrystalline TiO2 films

    王忠胜; 黄春辉; 李富友; 杨术明; 翁诗甫; 付小艺; 吴念祖; 奎热西; 刘凤琴; 钱海杰

    2001-01-01

    Self-assembled (SA) films (PMP, M = Ce3+ or Ce4+) of 3,4,9,10-perylenetetracarboxylic acid (PTA) on nanocrystalline TiO2 films with Ce3+ or Ce4+ as a bridge were fabricated and characterized with UV-Vis, IR, and XPS synchrotron radiation photoelectron spectroscopy (SRPES) which gave the HOMO energy levels for the SA films. It was shown that thin-layer sandwich-type solar cells based on these SA films possess good properties for photoelectric conversion. While PTA-loaded TiO2 electrode (P) generated 26.9% of incident monochromatic photon-to-electron conversion efficiency (IPCE), PMP-sensitized Ti02 electrodes yielded 55.8% and 39.1% for Ce4+ and Ce3+ respectively. PMP films can be considered as a kind of complexes whose HOMO energy levels were proved to be higher than that of film P, which is one of the major reasons for the increase in IPCE from film P to film PMP.

  12. Self-Assembled Film of Tb3+ and Poly(3-Thiophene Acetic Acid) via Layer-by-Layer Complexation Technique and Its Photoluminescence

    辛颢; 李富友; 黄岩谊; 黄春辉

    2002-01-01

    The layer-by-layer complexation technique of polymer and metal ion was successfully utilized to fabricate the ultrathin multilayer film of poly(3-thiophene acetic acid (PTAA) and Tb3+ ion by dipping the substrates alternatively in polymer and Tb3+ ion aqueous solutions. UV-vis measurement revealed that the absorbance has linearity with the bilayer number from layer to layer and the X-ray photoelectron spectrum (XPS) confirmed the existence of Tb3+ ion. The pH of both the polymer and TbCl3 solutions influence the thickness dramatically while the concentration of the solutions is not so sensitive. The luminescent spectrum of the complex film shows the characteristic emission of Tb3+ ion as well as the ligand indicating the formation of the complex.

  13. Acid diffusion through polymer films

    Zhang, P. Linda; Eckert, Andrew R.; Willson, C. Grant; Webber, Stephen E.; Byers, Jeffrey D.

    1997-07-01

    In order to perform 0.2 micrometer processes, one needs to study the diffusion of photoacid generators within the photoresist system, since diffusion during post exposure bake time has an influence on the critical dimension (CD). We have developed a new method to study the diffusion of photoacid generators within a polymer film. This new method is based on monitoring the change of the fluorescence intensity of a pH- sensitive fluorescent dye caused by the reaction with photoacid. A simplified version of this experiment has been conducted by introducing acid vapor to quench the fluorescence intensity of this pH sensor. A thin polymer film is spin cast onto the sensor to create a barrier to the acid diffusion process. During the acid diffusion process, the fluorescence intensity of this pH sensor is measured in situ, using excitation and emission wavelengths at 466 nm and 516 nm, respectively. Fluoresceinamine, the pH sensitive fluorescent dye, is covalently bonded onto the treated quartz substrate to form a single dye layer. Poly(hydroxystyrene) (Mn equals 13k, Tg equals 180 degrees Celsius) in PGMEA (5% - 18% by weight) is spin cast onto this quartz substrate to form films with varying thickness. The soft bake time is 60 seconds at 90 degrees Celsius and a typical film has a thickness of 1.4 micrometers. Trifluoroacetic acid is introduced into a small chamber while the fluorescence from this quartz window is observed. Our study focuses on finding the diffusion constant of the vaporized acid (trifluoroacetic acid) in the poly(hydroxystyrene) polymer film. By applying the Fick's second law, (It - Io)/(I(infinity ) - Io) equals erfc [L/(Dt)1/2] is obtained. The change of fluorescence intensity with respect to the diffusion time is monitored. The above equation is used for the data analysis, where L represents the film thickness and t represents the average time for the acid to diffuse through the film. The diffusion constant is calculated to be at the order of 10

  14. The effect of dual complexing agents of lactic and citric acids on the formation of sol-gel derived Ag–PbTiO{sub 3} percolative thin film

    Su, Yanbo; Hu, Tao; Tang, Liwen; Weng, Wenjian; Han, Gaorong; Ma, Ning; Du, Piyi, E-mail: dupy@zju.edu.cn

    2014-05-02

    Controlling the formation of conductive particles to be nano-scale is important for achieving percolation effect in metal dispersed thin film composite to contribute extraordinary dielectric properties required for miniaturization of electronic devices. In this paper, lactic acid (LA) and citric acid (CA) were used as dual complexing agents to prepare a typical Ag nanoparticle dispersed PbTiO{sub 3} (PTO) composite thin film by using a sol-gel method. The phase structure of the thin film and the coordination effect between complexing agent and metallic ions were investigated. It revealed that LA coordinated with Ti{sup 4+} and Pb{sup 2+} and CA coordinated with Ag{sup +}. Lead was fixed inside the gel network by LA and restricted to evaporate during heat treatment thus the pyrochlore phase was prevented from forming in the thin film. Ag{sup +} was coordinated by CA and the diffusion and thus aggregation of silver during gelation and annealing process were weakened. Silver nanoparticles dispersed in the PTO matrix formed with dual complexing agents of LA and CA introduced during the preparation process. The composite thin film of perfect perovskite phase with silver nanoparticles embedded was obtained at the molar ratio of LA/lead = 0.5 and CA/lead = 0.5. The dielectric constant of the thin film with silver nanoparticles is 5 times higher than that without silver nanoparticles. - Highlights: • Ag nanoparticle–PbTiO{sub 3} percolative film with high dielectric property is prepared. • Evaporation of lead was prevented by coordinating Pb with lactic acid agent. • Dual complexing agents contribute block and pinning effects to form Ag nanoparticles.

  15. Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities

    Van Wyngarden, A. L.; Pérez-Montaño, S.; Bui, J. V. H.; Li, E. S. W.; Nelson, T.E.; Ha, K. T.; L. Leong; Iraci, L.T.

    2014-01-01

    Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40–80 wt %) in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric ...

  16. Europium complexes with trifluoroacetic acid

    Synthesis conditions and spectra-luminescent properties of different-ligand europium complexes of the composition Eu (TFA)2x2D, where TFA = anion of trifluoroacetic acid, D = 1,10-phenanthroline, 2,2-dipyridyl, triphenylphosphinoxide, hexamethyl-phosphotriamide, were studied. The compounds prepared have been characterized by the methods of elementary chemical analysis, IR and luminescence spectroscopy. It is shown that in the complex compounds two methods of coordination of the acid residue functional groups are realized, i.e. monodentate and bridge functions. The compounds were tested for resistance to UV light effect and to heating in the air. Complex with 2,2-dipyridyl proved the most thermally stable complex in the series studied, its decomposition temperature being 240 deg C

  17. Growth of nitric acid hydrates on thin sulfuric acid films

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-01-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  18. Growth of nitric acid hydrates on thin sulfuric acid films

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-05-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1 - 3 × 10-4 Torr H2O and 1 - 2.5 × 10-6 Torr HNO3) and subjected to cooling and heating cycles. FTIR spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  19. Salicylic acid electrooxidation. A surface film formation

    Baturova, M.D.; Vedenjapin, A.; Baturova, M.M. [N.D. Zelinsky Inst. of Organic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Weichgrebe, D.; Danilova, E.; Rosenwinkel, K.H. [Univ. of Hannover, Inst. of Water Quality and Waste Management Hannover (Germany); Skundin, A. [A.N. Frumkin Inst. of Electrochemistry, Russian Academy of Sciences, Moscow (Russian Federation)

    2003-07-01

    A possibility to use electrochemical treatment for salicylic acid (SA) removal from waste water was studied. It was found that SA can be oxidized at platinum anode with formation of harmless products. Features of anodic process, in particular, formation of solid film on anode surface as well as properties of the film were investigated. (orig.)

  20. Complexes of salicylic acid and its derivatives

    A generalization and systematization have been made of literature data on complexing of various elements, including beryllium, cadmium, boron, indium, rare-earth elements, actinides, and transition elements with salicylic acid and it derivatives (amino-, nitro- and halosalicylic acids). The effect of the position and nature of the substitute, in the case of salicylic acid derivatives, on the complexing process is discussed. Certain physicochemical properties of the complexes under consideration are described along with data indicative of their stability

  1. Electrophoretic deposition of tannic acid-polypyrrolidone films and composites.

    Luo, Dan; Zhang, Tianshi; Zhitomirsky, Igor

    2016-05-01

    Thin films of polyvinylpyrrolidone (PVP)-tannic acid (TA) complexes were prepared by a conceptually new strategy, based on electrophoretic deposition (EPD). Proof of concept investigations involved the analysis of the deposition yield, FTIR and UV-vis spectroscopy of the deposited material, and electron microscopy studies. The analysis of the deposition mechanism indicated that the limitations of the EPD in the deposition of small phenolic molecules, such as TA, and electrically neutral polymers, similar to PVP, containing hydrogen-accepting carbonyl groups, can be avoided. The remarkable adsorption properties of TA and film forming properties of the PVP-TA complexes allowed for the EPD of materials of different types, such as huntite mineral platelets and hydrotalcite clay particles, TiO2 and MnO2 oxide nanoparticles, multiwalled carbon nanotubes, TiN and Pd nanoparticles. Moreover, PVP-TA complexes were used for the co-deposition of different materials and formation of composite films. In another approach, TA was used as a capping agent for the hydrothermal synthesis of ZnO nanorods, which were then deposited by EPD using PVP-TA complexes. The fundamental adsorption and interaction mechanisms of TA involved chelation of metal atoms on particle surfaces with galloyl groups, π-π interactions and hydrogen bonding. The films prepared by EPD can be used for various applications, utilizing functional properties of TA, PVP, inorganic and organic materials of different types and their composites. PMID:26878711

  2. Ruthenium nitrosyl complexes in nitric acid solutions

    Nine nitrosyl ruthenium complexes have been separated and identified in aqueous solutions of nitric acid. The separation method was low temperature, gradient elution, reverse phase partition chromatography using tri-n-butyl phosphate on a kiesel gel 60 support using 106Ru labelled complexes in the nitric acid phase. The identification of the complexes was deduced from the relationships between the products of aquation and nitration and paper chromatography using both methyl-iso-propyl ketone and nitric acid-acetone elutions. The proportion of each complex at equilibrium in various concentrations of nitric acid have been measured. The rates of nitration in 10 M nitric acid, and of aquation in 0.45 M nitric acid have been determined at 00C. (author)

  3. Photoactive thin films of polycaprolactam doped with europium (III) complex using phenylalanine as ligand

    Santos Garcia, Irene Teresinha, E-mail: irene@iq.ufrgs.br [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Bairro Agronomia, CEP 91501-970, Porto Alegre, RS (Brazil); Velleda Ribeiro, Patricia; Silva Correa, Diogo; Neto da Cunha, Igor Michel; Lenin Villarreal Carreno, Neftali [Instituto de Quimica e Geociencias, Universidade Federal de Pelotas, Campus Capao do Leao, s/n. CEP 96010-900, Pelotas, RS (Brazil); Ceretta Moreira, Eduardo [PPGEE, Universidade Federal do Pampa, Campus Bage, Bage- RS (Brazil); Severo Rodembusch, Fabiano [Departamento de Quimica Organica, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Bairro Agronomia, CEP 91501-970, Porto Alegre, RS (Brazil)

    2011-12-01

    A photoactive complex based on europium(III) using the amino acid phenylalanine as ligand was prepared and characterized. The obtained europium(III)/phenylalanine complex presents an effective energy transfer from ligands to the rare earth center. The observed photoluminescent behavior for europium(III)/phenylalanine complex was similar to the well known europium(III)/ acetyl-{beta}-acetonate hydrate. New photoactive polyamide thin films were prepared using polycaprolactam as host of these complexes. The structural characterizations of the films were studied through Rutherford backscattering (RBS), Fourier transform infrared (FTIR) and Raman spectroscopies. The polyamide films doped with the amino acid and acetyl-{beta}-acetonate rare earth complexes maintain the original photoluminescent behavior, narrow emission bands corresponding to transitions {sup 5}D{sub 0} {yields} {sup 7}F{sub 0-4}, which indicates that this polymer is an excellent host to these complexes.

  4. Complexation of americium with humic acid

    As a part of the interlaboratory comparison exercise for the complexation of humic acid and colloid generation (COCO-Club activities) in the CEC project MIRAGE-II, the complexation of americium with humic acid has been studied in our laboratory. Two humic acids were used for the study: Aldrich-HA(H+) which is a reference humic acid of the COCO-Club and Bradford-HA(H+) from Lake Bradford, Florida. A wide concentration range of humic acid and different ratios of Am to humic acid have been investigated between pH 5 and 6 with the ionic strength of 0.1 M and 1.0 M. The complexation has been studied by UV-spectroscopy, Laser-induced Photoacoustic Spectroscopy (LPAS) and ultrafiltration. LPAS is used for the submicromolar concentration range where the sensitivity of UV spectroscopy is not accessible. Ultrafiltration is used for low Am to humic acid ratios where both spectroscopic methods are not applicable. Varying the humic acid concentration over three orders of magnitude, only a 1:1 type of binding is observed. No significant variation of the stability constant is found in the investigated range of pH and ionic strength. However, the precipitation tendency and the loading capacity of humic acid are found to depend sensitively on pH and ionic strength. The complexation study provides a deep insight into the influence of humic acid on the migration behaviour of fission products and actinides in the geosphere. (orig.)

  5. Influence of complexing agent on the growth of chemically deposited Ni3Pb2S2 thin films

    Ho Soonmin

    2014-09-01

    Full Text Available Ni3Pb2S2 thin films were prepared by chemical bath deposition method. Here, the objective of this research was to investigate the influence of complexing agent on the properties of films.These films were characterized using atomic force microscopy, UV-Visible spectro photometer and X-ray diffraction. It was found that, as the concentration of tartaric acid increased, film thickness increased, but, the band gap reduced. For the films prepared using 0.1M of tartaric acid, the films were uniform and completely covered the substrates.

  6. Characterization and complexation of humic acid

    This paper summarizes the research contributions to the CEC project MIRAGE II, particularly the research area: complexation and colloids (COCO). The first part of the paper comprises the characterization of humic and fulvic acids from different origins: a commercial product from Aldrich Co. used as a reference humic acid and site specific humic acids from Gorleben (FRG), Boom Clay (B) and Fanay Augeres (F) aquifer systems. The second part includes the complexation of trivalent actinides: Am(III) and Cm(III) with various humic acids. A number of different methods have been applied for the complexation study: spectrophotometry, ultrafiltration, laser-indused photoacoustic spectroscopy (LPAS) and time resolved laser fluorescence spectroscopy (TRLFS). The evaluation process of complexation constant is discussed extensively and the well consolidated results are presented, which can be directly used for the geochemical modelling of the radionuclide migration. (orig.)

  7. Complex coacervates of hyaluronic acid and lysozyme

    Water, Jorrit J.; Schack, Malthe M.; Velazquez-Campoy, Adrian;

    2014-01-01

    Complex coacervates of hyaluronic acid and lysozyme, a model protein, were formed by ionic interaction using bulk mixing and were characterized in terms of binding stoichiometry and protein structure and stability. The complexes were formed at pH 7.2 at low ionic strength (6 mM) and the binding...... stoichiometry was determined using solution depletion and isothermal titration calorimetry. The binding stoichiometry of lysozyme to hyaluronic acid (870 kDa) determined by solution depletion was found to be 225.9 ± 6.6 mol, or 0.1 bound lysozyme molecules per hyaluronic acid monomer. This corresponded well...... with that obtained by isothermal titration calorimetry of 0.09 bound lysozyme molecules per hyaluronic acid monomer. The complexation did not alter the secondary structure of lysozyme measured by Fourier-transform infrared spectroscopy overlap analysis and had no significant impact on the Tm of...

  8. Complex film of chitosan and carboxymethyl cellulose nanofibers.

    Kawasaki, Takuma; Nakaji-Hirabayashi, Tadashi; Masuyama, Kazuhira; Fujita, Satoshi; Kitano, Hiromi

    2016-03-01

    A polymer film composed of a mixture of chitosan (Ch) and carboxymethyl cellulose sodium salt (CMC) nanofibers was deposited on a glass surface. The thin film of the Ch-CMC mixture obtained was stable, and fibroblast adhesion to the film was lowest when the weight ratio of Ch to CMC was 4:6. The ζ-potential and contact angle of the mixture film indicated that a polyion complex of Ch and CMC was formed. The mechanical strength of the film composed of Ch-CMC nanofiber complexes was much higher than that of the film composed of Ch-water-soluble CMC complexes (non-nanofiber), likely because the entanglement of nanofibers was enhanced by electrostatic attractions. These results indicate that the charge-neutralized nanofiber film was highly effective in suppressing cell adhesion and therefore is a promising material for biomedical applications. PMID:26700238

  9. Methods for producing complex films, and films produced thereby

    Duty, Chad E.; Bennett, Charlee J. C.; Moon, Ji -Won; Phelps, Tommy J.; Blue, Craig A.; Dai, Quanqin; Hu, Michael Z.; Ivanov, Ilia N.; Jellison, Jr., Gerald E.; Love, Lonnie J.; Ott, Ronald D.; Parish, Chad M.; Walker, Steven

    2015-11-24

    A method for producing a film, the method comprising melting a layer of precursor particles on a substrate until at least a portion of the melted particles are planarized and merged to produce the film. The invention is also directed to a method for producing a photovoltaic film, the method comprising depositing particles having a photovoltaic or other property onto a substrate, and affixing the particles to the substrate, wherein the particles may or may not be subsequently melted. Also described herein are films produced by these methods, methods for producing a patterned film on a substrate, and methods for producing a multilayer structure.

  10. Preparation and Properties of Vegetable-Carboxymethylcellulose (CMC) Complex FilmsЦ Water Bamboo-CMC,Chinese Cabbage-CMC etc.Complex Films

    2007-01-01

    1 Results Various kinds of biodegradable polymers have been researched[1].In our previous papers,cellulose-alginic acid[2],cellulose-agar[3],vegetable-carboxymethylcellulose (CMC) etc.complex films have been researched.Recently,some other kinds of vegetable such as water bamboo,Chinese cabbage,eggplant,spinach,naked oats,and basella,asparagus and pumpkin were used to perpare vegetable-CMC complex films.Every kind of vegetable has different content of water,cellulose,protein,carbohydrate and a small amou...

  11. Catalytically active cobalt and copper complexes in polyelectrolyte multilayer films

    In this work an approach to obtain effective and easy reusable heterogeneous catalyst, LbL deposition of polyelectrolytes followed by covalently binding with cobalt (II) and copper (II) ions were described. Immobilization of metal complexes via covalent attachment to insoluble template is an attractive method to facilitate catalyst recovery, recycling. The reaction in the heterogeneous catalysis goes in the interface of catalyst and reaction solution and it is important to create a catalyst with large surface area. We have used polycations as polyethyleneimine (BPEI), quaternized poly(4- vynilpyridine) (QPVP) and polyanions as poly(acrylic acid) (PAA), poly(styrene sulphonate) sodium salt (PSS) and the electrostatic layer-by-layer assembly technique to make uniform thin film coating on SiO2 nanoparticles and glass slides with controllable thickness, roughness and mechanically durability. The stability of metals within multilayers in reaction condition were tested. We compared the amount of metal in PEMs of different polyelectrolytes. The stability constants of complex forming processes of the polymer-metal complexes in water and in alcohol were calculated by modified method of Bjerrum. Catalytic activity of immobilized catalysts was investigated for oxidation of toluene by molecular oxygen. Catalysts were separated from reaction mixture easily and had been used for this reaction five times without significant loss of activity. Key words: catalysis, layer-by-layer (LbL), polymer-metal complexes, oxidation, cobalt and copper immobilization

  12. A Complexity View of Acid Deposition

    朱建林; 方见树

    2003-01-01

    We show that acid deposition is analogous to complex systems composed of a series of interconnected components.Frequency-size distributions of weekly hydrogen deposition (WHD) of precipitation are consistent with double power-law in two different regimes separated by a crossover WHD. The distribution of variations in acid deposition over a week interval is remarkably symmetrical, with long tail extending over eight orders of magnitude. The acid deposition fluctuations exhibit fractal Brown motion with two different temporal scaling regimes and long-range correlation exists in the series. The power-laws in the acid deposition dynamics are considered to be indicators of seff-organization of atmosphere under environmental pollution stress.

  13. Sprayed films of europium complexes toward light conversion devices

    Rare-earth complexes have become subject of intensive research due to the high quantum efficiency of their emission, very narrow bands, and excellent fluorescence monochromaticity. The chemical design and characterization of Eu complexes based on β-diketone ligands hexafluoroacetylacetate (hfac) and dibenzoylmetanate (dbm) is reported here. K[Eu(dbm)4] and K[Eu(hfac)4] complexes were immobilized as thin films by using the spray technique, a promising methodology for practical applications. The latter provides not only a faster layer deposition but also larger coated areas compared to conventional methods, such as layer-by-layer (LbL) and Langmuir–Blodgett (LB). The growth of the sprayed films was monitored through microbalance (QCM) and ultraviolet–visible (UV–Vis) absorption spectroscopy, which reveal a higher mass and absorbance per deposited layer of K[Eu(dbm)4] film. Micro-Raman images display a more homogeneous spatial distribution of the K[Eu(dbm)4] complex throughout the film, when compared to K[Eu(hfac)4] film. At nanometer scale, atomic force microscopy (AFM) images indicate that the roughness of the K[Eu(hfac)4] film is approximately one order of magnitude higher than that for the K[Eu(dbm)4] film, which pattern is kept at micrometer scale according to micro-Raman measurements. The photoluminescence data show that the complexes remain as pure red emitters upon spray immobilization. Besides, the quantum efficiency for the sprayed films are found equivalent to the values achieved for the powders, highlighting the potential of the films for application in light conversion devices. - Highlights: • Rare earth complexes thin films based on β-diketone ligands. • Spraying procedures to fabricate layer-by-layer (LbL) luminescent thin films. • Chemical design of Eu complexes based on hfac and dbm β-diketones ligands immobilized as sprayed films. • Pure red emitters upon spray immobilization. • Sprayed luminescent thin films for potential

  14. Oral absorption of hyaluronic acid and phospholipids complexes in rats

    Si-Ling Huang; Pei-Xue Ling; Tian-Min Zhang

    2007-01-01

    AIM: To prepare a complex of hyaluronic acid (HA) and phospholipids (PL), and study the improvement effect of PL on the oral absorption of HA.METHODS: The complex of HA-PL (named Haplex) was prepared by film dispersion and sonication method, its physico-chemical properties were identified by infrared spectra and differential scanning calorimetry (DSC). The oral absorption of Haplex was studied. Thirty-two healthy rats were divided into 4 groups randomly: (1) a normal saline (NS) control group; (2) an HA group; (3) a mixture group and (4) a Haplex group. After intragastric administration, the concentration of HA in serum was determined.RESULTS: The physico-chemical properties of Haplex were different from HA or PL or their mixture. After Haplex was administered to rats orally, the serum concentration of HA was increased when compared with the mixture or HA control groups from 4 h to 10 h (P < 0.05). The ΔAUCo-12 h of Haplex was also greater than that of the other three groups (P < 0.05).CONCLUSION: The method of film dispersion and sonication can prepare HA and PL complex, and PL can enhance the oral absorption of exogenous HA.

  15. Complex Pharmacology of Free Fatty Acid Receptors

    Milligan, Graeme; Shimpukade, Bharat; Ulven, Trond;

    2016-01-01

    G protein-coupled receptors (GPCRs) are historically the most successful family of drug targets. In recent times it has become clear that the pharmacology of these receptors is far more complex than previously imagined. Understanding of the pharmacological regulation of GPCRs now extends beyond...... pharmacology have shaped understanding of the complex pharmacology of receptors that recognize and are activated by nonesterified or "free" fatty acids (FFAs). The FFA family of receptors is a recently deorphanized set of GPCRs, the members of which are now receiving substantial interest as novel targets for...... the treatment of metabolic and inflammatory diseases. Further understanding of the complex pharmacology of these receptors will be critical to unlocking their ultimate therapeutic potential....

  16. Formation of complex anodic films on porous alumina matrices

    Alexander Zahariev; Assen Girginov

    2003-04-01

    The kinetics of growth of complex anodic alumina films was investigated. These films were formed by filling porous oxide films (matrices) having deep pores. The porous films (matrices) were obtained voltastatically in (COOH)2 aqueous solution under various voltages. The filling was done by re-anodization in an electrolyte solution not dissolving the film. Data about the kinetics of re-anodization depending on the porosity of the matrices were obtained. On the other hand, the slopes of the kinetic curves during reanodization were calculated by two equations expressing the dependence of these slopes on the ionic current density. A discrepancy was ascertained between the values of the calculated slopes and those experimentally found. For this discrepancy a possible explanation is proposed, related to the temperature increase in the film, because of that the real current density significantly increases during re-anodization.

  17. Lactic Acid and Biosurfactants Production from Residual Cellulose Films.

    Portilla Rivera, Oscar Manuel; Arzate Martínez, Guillermo; Jarquín Enríquez, Lorenzo; Vázquez Landaverde, Pedro Alberto; Domínguez González, José Manuel

    2015-11-01

    The increasing amounts of residual cellulose films generated as wastes all over the world represent a big scale problem for the meat industry regarding to environmental and economic issues. The use of residual cellulose films as a feedstock of glucose-containing solutions by acid hydrolysis and further fermentation into lactic acid and biosurfactants was evaluated as a method to diminish and revalorize these wastes. Under a treatment consisting in sulfuric acid 6% (v/v); reaction time 2 h; solid liquid ratio 9 g of film/100 mL of acid solution, and temperature 130 °C, 35 g/L of glucose and 49% of solubilized film was obtained. From five lactic acid strains, Lactobacillus plantarum was the most suitable for metabolizing the glucose generated. The process was scaled up under optimized conditions in a 2-L bioreactor, producing 3.4 g/L of biomass, 18 g/L of lactic acid, and 15 units of surface tension reduction of a buffer phosphate solution. Around 50% of the cellulose was degraded by the treatment applied, and the liqueurs generated were useful for an efficient production of lactic acid and biosurfactants using L. plantarum. Lactobacillus bacteria can efficiently utilize glucose from cellulose films hydrolysis without the need of clarification of the liqueurs. PMID:26293409

  18. Characterization and bacterial adhesion of chitosan-perfluorinated acid films.

    Bierbrauer, Karina L; Alasino, Roxana V; Muñoz, Adrián; Beltramo, Dante M; Strumia, Miriam C

    2014-02-01

    We reported herein the study and characterization of films obtained by casting of chitosan solutions in perfluorinated acids, trifluoroacetic (TFA), perfluoropropionic (PFPA), and perfluorooctanoic (PFOA). The films were characterized by FTIR, solid state (13)C NMR, X-ray, AFM, contact angle, thermogravimetric effluent analysis by mass spectrometry, and rheology. The results showed a marked influence of chain length of the perfluorinated acids on the hydrophobic/hydrophilic ratio of the modified chitosan films which was evidenced by the different characteristics observed. The material that showed greater surface stability was chitosan-PFOA. Chitosan film with the addition of PFOA modifier became more hydrophobic, thus water vapor permeability diminished compared to chitosan films alone, this new material also depicted bacterial adhesion which, together with the features already described, proves its potential in applications for bioreactor coating. PMID:24189195

  19. Biotransformation of plutonium complexed with citric acid

    Francis, A.J.; Dodge, C.J.; Gillow, J.B. [Environmental Sciences Department, Brookhaven National Laboratory, Upton, New York, 11973 (United States)

    2005-07-01

    Full text of publication follows: The presence of organic ligands in radioactive wastes is a major concern because of the potential for increasing the transport of radionuclides from disposal sites. Microorganisms present in radioactive wastes can affect the long-term stability of radionuclides associated with organic ligands. Biotransformation of radionuclides complexed with organic ligands should result in the precipitation of the radionuclides and retard their migration. In this study we investigated the biotransformation of {sup 242}Pu{sup 4+} (10{sup -8} to 10{sup -5} M) in the presence of equimolar and excess citric acid by Pseudomonas fluorescens. Analysis of {sup 242}Pu-citrate by electro-spray ionization-mass spectrometry (ESI-MS) indicated the presence of a bi-ligand Pu-cit{sub 2} complex. Analysis of Th-citrate complex, an analog for Pu-citrate, indicated the formation of a 2:3 complex. Citric acid under aerobic conditions was metabolized by P. fluorescens at a rate of 4.9 {mu}M/h, and decreased to 4.0 and 3.8 {mu}M/h in the presence of 10{sup -8} and 10{sup -6} M of Pu, respectively. The pH of the medium containing citric acid alone increased from 6.5 to 7.1, while the pH of the samples containing Pu increased from 6.8 to 7.9. The high ionic strength (0.9 M) of the medium reduced citric acid metabolism by 50% in comparison to 0.1 M ionic strength. Initially, Pu added to the growth medium as Pu-citrate remained in solution as Pu{sup 4+}. Selective solvent extraction by thenyl-tri-fluoro-acetone (TTA) as well as micro-filtration (0.03 {mu}m) of the medium after biodegradation studies indicated that Pu was present as the polymeric form. The Pu polymer formation was dependent on the Pu:citrate ratio as well as the extent of citrate metabolism. The high ionic strength solution containing 10{sup -5} M 1:1 Pu-citrate complex showed only 27% citrate degradation but had the highest percentage ({approx}80%) of polymer formation, suggesting the Pu was soluble only

  20. Biotransformation of plutonium complexed with citric acid

    Full text of publication follows: The presence of organic ligands in radioactive wastes is a major concern because of the potential for increasing the transport of radionuclides from disposal sites. Microorganisms present in radioactive wastes can affect the long-term stability of radionuclides associated with organic ligands. Biotransformation of radionuclides complexed with organic ligands should result in the precipitation of the radionuclides and retard their migration. In this study we investigated the biotransformation of 242Pu4+ (10-8 to 10-5 M) in the presence of equimolar and excess citric acid by Pseudomonas fluorescens. Analysis of 242Pu-citrate by electro-spray ionization-mass spectrometry (ESI-MS) indicated the presence of a bi-ligand Pu-cit2 complex. Analysis of Th-citrate complex, an analog for Pu-citrate, indicated the formation of a 2:3 complex. Citric acid under aerobic conditions was metabolized by P. fluorescens at a rate of 4.9 μM/h, and decreased to 4.0 and 3.8 μM/h in the presence of 10-8 and 10-6 M of Pu, respectively. The pH of the medium containing citric acid alone increased from 6.5 to 7.1, while the pH of the samples containing Pu increased from 6.8 to 7.9. The high ionic strength (0.9 M) of the medium reduced citric acid metabolism by 50% in comparison to 0.1 M ionic strength. Initially, Pu added to the growth medium as Pu-citrate remained in solution as Pu4+. Selective solvent extraction by thenyl-tri-fluoro-acetone (TTA) as well as micro-filtration (0.03 μm) of the medium after biodegradation studies indicated that Pu was present as the polymeric form. The Pu polymer formation was dependent on the Pu:citrate ratio as well as the extent of citrate metabolism. The high ionic strength solution containing 10-5 M 1:1 Pu-citrate complex showed only 27% citrate degradation but had the highest percentage (∼80%) of polymer formation, suggesting the Pu was soluble only in the presence of excess citric acid. However, the extensive

  1. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nicotinamide-ascorbic acid complex. 172.315 Section... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex. Nicotinamide-ascorbic acid complex may be safely used in accordance with the following prescribed...

  2. Influence of citric acid on the morphology and magnetic properties of barium ferrite thin films

    Hexagonal barium ferrite (BaFe12O19) thin films were fabricated by spin coating of precursors from sol-gel methods. Different amount of citric acid was added. Weight loss and changes of chemical bonds during the heat treatment below 500 deg. C were recorded by thermogravity analyzer and Fourier transform infrared spectroscopy, respectively. The morphology of the films, i.e. the amount of acicular crystallites in the film, was controlled by adjusting the quantity of citric acid. The X-ray diffraction shows that the films are c-axis oriented, but the crystallization is less perfect with the increase of the citric acid. With the increase of the citric acid, the percentage of the acicular crystallites increased. At the same time, the coercivity force increased. The acicular crystallites were not exchange-coupled to the platelet crystallites. The citric acid was understood to form complex with iron ions and accelerate the exothermal auto-combustion. The c-axis oriented growth of the film was thus deteriorated.

  3. Complex formation of calcium with humic acid and polyacrylic acid

    In order to understand the migration behavior of radionuclides in the underground, it is also important to estimate the effect of the competing cations originally present in the groundwater. In this connection, the complexation of Ca(II) with Aldrich humic acid has been examined. For the study at trace concentrations (∝ 10-10 M) of Ca(II), the solvent extraction of 45Ca with TTA and TOPO in cyclohexane has been used. At macro concentrations (10-4 M) of Ca(II), the measurement of the free Ca2+ ion concentration with a calcium selective electrode has been conducted. To estimate the polyelectrolyte effect of humic acid separately from its heterogeneous composition effect, polyacrylic acid ([-CH2CH(COOH)-]n) has been selected as a representative of the homogeneous polymeric weak acids and its complexation with Ca(II) has also been examined. The values of log βα have been obtained at pH 5 ∝ 7 in 0.1, 0.4 and 1.0 M NaCl, where βα is the apparent formation constants defined by βα = [ML]/([M][R]). In this definition, [ML] and [M] are the concentrations of bound and free Ca2+ respectively, [R] is the concentration of dissociated proton exchanging sites. log βα of humate decreases from 2.19 ∝ 2.92 (depending on pH and ionic strength 1.0 α of polyacrylate (1.36 ∝ 3.24 for I = 0.1 ∝ 1.0). For both humate and polyacrylate, log βα decreases linearly with log[Na+], where [Na+] is the bulk concentration of sodium ion. Their dependences of log βα on ionic strength are stronger than those of log β of monomeric carboxylates such as oxalate and EDTA, indicating the large electrostatic effect of crowded negative charges on the macromolecules of humic or polyacrylic acid. (orig.)

  4. Comparison of topotactic fluorination methods for complex oxide films

    Moon, E. J., E-mail: em582@drexel.edu; Choquette, A. K.; Huon, A.; Kulesa, S. Z.; May, S. J., E-mail: smay@coe.drexel.edu [Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104 (United States); Barbash, D. [Centralized Research Facilities, Drexel University, Philadelphia, Pennsylvania 19104 (United States)

    2015-06-01

    We have investigated the synthesis of SrFeO{sub 3−α}F{sub γ} (α and γ ≤ 1) perovskite films using topotactic fluorination reactions utilizing poly(vinylidene fluoride) as a fluorine source. Two different fluorination methods, a spin-coating and a vapor transport approach, were performed on as-grown SrFeO{sub 2.5} films. We highlight differences in the structural, compositional, and optical properties of the oxyfluoride films obtained via the two methods, providing insight into how fluorination reactions can be used to modify electronic and optical behavior in complex oxide heterostructures.

  5. Comparison of topotactic fluorination methods for complex oxide films

    E. J. Moon

    2015-06-01

    Full Text Available We have investigated the synthesis of SrFeO3−αFγ (α and γ ≤ 1 perovskite films using topotactic fluorination reactions utilizing poly(vinylidene fluoride as a fluorine source. Two different fluorination methods, a spin-coating and a vapor transport approach, were performed on as-grown SrFeO2.5 films. We highlight differences in the structural, compositional, and optical properties of the oxyfluoride films obtained via the two methods, providing insight into how fluorination reactions can be used to modify electronic and optical behavior in complex oxide heterostructures.

  6. Fabrication of Superhydrophobic and Luminescent Rare Earth/Polymer complex Films.

    Wang, Zefeng; Ye, Weiwei; Luo, Xinran; Wang, Zhonggang

    2016-01-01

    The motivation of this work is to create luminescent rare earth/polymer films with outstanding water-resistance and superhydrophobicity. Specifically, the emulsion polymerization of styrene leads to core particles. Then core-shell-structured polymer nanoparticles are synthesized by copolymerization of styrene and acrylic acid on the core surface. The coordination reaction between carboxylic groups and rare earth ions (Eu(3+) and Tb(3+)) generates uniform spherical rare earth/polymer nanoparticles, which are subsequently complexed with PTFE microparticles to obtain micro-/nano-scaled PTFE/rare earth films with hierarchical rough morphology. The films exhibit large water contact angle up to 161° and sliding angle of about 6°, and can emit strong red and green fluorescence under UV excitation. More surprisingly, it is found that the films maintain high fluorescence intensity after submersed in water and even in aqueous salt solution for two days because of the excellent water repellent ability of surfaces. PMID:27086735

  7. SURFACE OF GELATIN MODIFIED POLY(L-LACTIC ACID) FILM

    Xin Hou; Bao-long Zhang; Feng She; Yuan-lu Cui; Ke-yu Shi; Kang-de Yao

    2003-01-01

    In this paper, the surface structure of poly(L-lactic acid) (PLLA) film modified with gelatin was investigated. The PLLA film specimens were treated directly with aqueous alkali solution to provide their surfaces with carboxyl groups, so that these functional groups could become the reactive sites for gelatin immobilization. The functional groups of the PLLA films were identified by ATR-FTIR spectra and XPS spectra, the changes in surface morphology were observed by using environmental scanning electron microscopy (ESEM), and the hydrophilicity of modified PLLA films was examined by water contact angle measurement. Experimental results showed that the gelatin was immobilized with water-soluble carbodiimide (EDC) onto the PLLA film's surfaces, and the gelatin content on the polymer surface was related to carboxylic group formed in the controlled hydrolysis process. Rough surfaces caused by hydrolysis will predominantly favor the adhesion and growth of cell; and the hydrophilicity of these surfaces after the modification procedure is enhanced.

  8. Partly Imidized Polyamic Acid and Its Uniaxial Stretched Polyimide Films

    MA Peng-chang; HOU Yong

    2013-01-01

    Partly imidized polyamic acid(PAA) has been used to prepare high performance polyimide films.The behaviors of two polyamic acids derived from pyromellitic dianhydride(PMDA)/4,4'-oxydianiline(ODA) and 3,Y,4,4'-biphenyltetracarboxylic diahhydride(BPDA)/paraphenylenediamine(PPD) containing dehydrating agents composed of acetic anhydride and a tertiary amine as the catalyst were investigated.The gel point was dependent on imidization degree in despite of temperature and the molar ratio of catalyst to acetic acid.Imdization content was about 35% for PMDA/ODA and about 22% for BPDA/PPD.The effect of catalyst on imidization possessed an order of triethylamine>3-methylpyridine>pyridine>isoquinoline>2-methylpyridine.The stretching of the films greatly reduced the coefficient of linear thermal expansion(CTE) either in the longitudinal direction or transversal direction.Compared to the film from polyamic acid,the partly imidized film had greater stretching ratio,so that the uniaxial stretched polyimide film from partly imidized PAA had higher tensile strength and tensile modulus,but lower elongation in the stretching direction.

  9. Ni(II) complexes of dithiophosphonic acids

    Afshin Saadat; Alireza Banaee; Patrick McArdle; Karim Zare; Khodayar Gholivand; Ali Asghar Ebrahimi Valmoozi

    2014-07-01

    The reaction of 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson reagent) with isobutanol, cyclohexylamine and phenylethylamine produced (4-methoxy-phenyl)-phosphonodithioic acid o-isobutyl ester HS2P(p-C6H4OMe) (OCH2CH(CH3)2) (I), [S2P(C6H11NH)(p-C6H4OMe) H3N+C6H11] (II) and [S2P(phCH2CH2NH) (p-C6H4OMe)H3N+CH2CH2ph] (III), respectively. The reaction of alcohol with Lawesson reagent produced neutral product (I) while that with amines led to an ion pair (II, III). Furthermore, reaction of I, II and III with NiCl2.6H2O in methanol produced novel complexes: IV, V and VI. The compounds were characterized by 1H, 13C and 31P NMR, IR spectroscopy and elemental analysis. The single crystal X-ray structures of IV and V showed that the nickel complexes are square planar. Compound V formed a three-dimensional supramolecular structure via intermolecular P-O…H-N hydrogen bonds. The Xray crystallography of V showed that those three hydrogens of +NH3 cation produced three hydrogen bonds with different distances. The new compounds were additionally tested in view of their anti-bacterial properties. The ligands containing amine substituents exhibited more activity toward tested bacteria than their alcohol substituents, while the Ni(II) complexes including alcohol substituents exhibited high potential.

  10. Gelatin-Pectin Composite Films from Polyion Complex Hydrogels

    Composite films from gelatin and low-methoxyl pectin were prepared by either ionic complexation or covalent cross-linking. The ionic interactions between positively charged gelatin and negatively charged pectin produced physically reversible hydrogels. The resultant homogeneous gels had improved mec...

  11. Surface investigation of chitosan film with fatty acid monolayers

    Esam A. El-hefian

    2009-05-01

    Full Text Available The surface pressure- molecular area (-A isotherm curves of two fatty acids of different chain lengths, i.e. stearic (C18 and arachidic (C20 acids, were obtained by using Langmuir-Blodgett (LB technique. Results showed clear isotherm plots with limiting mean molecular area around 21 Å2 for both acids. However, the monolayer was found to collapse at higher than 33 mN m-1 and 21 mN m-1 for stearic acid and arachidic acid respectively. The effect of Langmuir-Blodgett monolayers of the acids was investigated by atomic force microscopy (AFM. Chitosan film, before and after dipping in water, was also studied by means of AFM so that it could be used for comparison. It was found that the surface of chitosan was more homogeneous and smoother after dipping in water. In addition, more homogeneous surfaces were achieved after transferring a layer of the fatty acid onto the substrate.

  12. Occurrence of single-electron phenomenon in CdS nanoclusters in Langmuir-Blodgett films of -octadecyl succinic acid

    G Hemakanthi; Aruna Dhathathreyan

    2002-10-01

    Cadmium complex of -octadecyl succinic acid (ODSA) in Langmuir films at air/water interface has been studied using surface pressure-molecular area ( - ) and surface potential-molecular area ( - ) isotherms. The metal complex formed, transferred as LB film onto solid substrates, was analysed using FT-IR and was subjected to sulphidation reaction. Antisymmetric and symmetric carboxylate stretching vibrations have been used to determine the nature of the ODSA/cation complexes. CdS formed after sulphidation of the cadmium complex (ODSACd) showed possible single-electron phenomenon indicating the nanosized nature of clusters formed. Atomic Force Microscopy (AFM) measurements carried out confirmed the size of these CdS clusters.

  13. Characterization of nanostructured As{sub 2}S{sub 3} thin films synthesized at room temperature by chemical bath deposition method using various complexing agents

    Ubale, Ashok U., E-mail: ashokuu@yahoo.com; Kantale, J.S.; Choudhari, D.M.; Mitkari, V.N.; Nikam, M.S.; Belkhedkar, M.R.

    2013-09-02

    Nanostructured binary As{sub 2}S{sub 3} thin films were deposited onto glass substrates by chemical bath deposition method from complexed and uncomplexed baths using complexing agents acetic acid, ethylenediaminetetraacetic acid, oxalic acid and tartaric acid. The effect of complexing agent on structural, electrical, morphological and optical properties of As{sub 2}S{sub 3} is reported. The synthesized films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical resistivity and optical absorption measurements. The deposited films are nanocrystalline in nature with monoclinic lattice. The films deposited from uncomplexed bath and from ethylenediaminetetraacetic acid complexes are non-porous and become porous for other complexes. The electrical resistivity and optical band gap is also found complex dependent. - Highlights: • Nanocrystalline n-type As{sub 2}S{sub 3} films were grown by chemical bath deposition method. • Effect of complex on structural, electrical and optical properties was reported. • The film morphology highly depends on complex used in deposition process.

  14. Thin films of perovskite-type complex oxides

    Hanns-Ulrich Habermeier

    2007-10-01

    Full Text Available Complex oxides represent a class of materials with a plethora of fascinating, intrinsic physical functionalities. The intriguing interplay of charge, spin, and orbital ordering in these systems superimposed by lattice effects opens a scientifically rewarding playground for both fundamental and application-oriented research. In particular, the possibility of externally modifying the properties of thin-film complex oxides by epitaxial strain or artificial boundaries, and thus potentially generating novel properties at the interfaces between films, opens a new perspective. Here, the development of physical vapor deposition based preparation technologies for complex oxide thin films is reviewed, with examples taken from current research in high-temperature superconducting cuprates, magnetically ordered manganites, and Na–cobaltates. It covers the main trends of in situ process and growth control to fabricate single-crystal, single-layer thin films, heterostructures, and superlattices. Furthermore, using the combination of ferromagnetic and superconducting oxides as a case study, the emerging field of engineering the electronic structure at the interface, and thus design of new functionalities, is highlighted.

  15. Mixed-metal hydroxycarboxylic acid complexes

    Formation constants for mixed-metal complexes, Kmmc, between uranium(VI), as the central metal ion, and each one of the metal ions, iron(III), aluminium(III), indium(III) and copper(II) have been determined using data from potentiometric measurements. In each case one of the hydroxycarboxylic acids, citric, tartaric or malic, was used as a ligand. At 298.15 K the values of -log Kmmc for the investigated systems are uranyl iron(II) citrate, 2.45; uranyl iron(III) malate, 7.37; uranyl aluminium(III) citrate, 8.21; uranyl aluminium(III) tartarate, >12; uranyl aluminium(III) malate, 8.06; uranyl indium(III) citrate, 11.3; uranyl indium(III) tartarate, 7.88; uranyl indium(III) malate, 7.45; uranyl copper(II) citrate -1.41; uranyl copper(II) tartarate, -1.17; and uranyl copper(II) malate, -1.11. (author)

  16. Characterisation and application of new carboxylic acid-functionalised ruthenium complexes as dye-sensitisers for solar cells

    Duprez, Virginie; Biancardo, Matteo; Krebs, Frederik C

    2007-01-01

    A series of ruthenium complexes with and without TiO2, anchoring carboxylic acid groups have been synthesised and characterised using nuclear magnetic resonance (NMR), UV-vis and luminescence. These complexes were adsorbed on thin films of the wide band-gap semiconductor anatase and were tested as...

  17. Dispersion Process and Effect of Oleic Acid on Properties of Cellulose Sulfate- Oleic Acid Composite Film

    Guo Chen

    2015-04-01

    Full Text Available The cellulose sulfate (CS is a newly developed cellulose derivative. The work aimed to investigate the effect of oleic acid (OA content on properties of CS-OA film. The process of oleic acid dispersion into film was described to evaluate its effect on the properties of the film. Among the formulations evaluated, the OA addition decreased the solubility and water vapor permeability of the CS-OA film. The surface contact angle changed from 64.2° to 94.0° by increasing CS/OA ratio from 1:0 to 1:0.25 (w/w. The TS increased with OA content below 15% and decreased with OA over 15%, but the ε decreased with higher OA content. The micro-cracking matrices and micro pores in the film indicated the condense structure of the film destroyed by the incorporation of oleic acid. No chemical interaction between the OA and CS was observed in the XRD and FTIR spectrum. Film formulation containing 2% (w/w CS, 0.3% (w/w glycerol and 0.3% (w/w OA, showed good properties of mechanic, barrier to moisture and homogeneity.

  18. Effects of complexing agents on electrochemical deposition of FeS x O y thin films

    Supee, Aizuddin; Ichimura, Masaya

    2016-08-01

    FeS x O y thin films were deposited on indium–tin-oxide (ITO)-coated glass substrates at 15 °C via galvanostatic electrochemical deposition from an aqueous solution containing 100 mM Na2S2O3 and 30 mM FeSO4. The effects of l(+)-tartaric acid (C4H4O6) and lactic acid [CH3CH(OH)COOH] at different concentrations were investigated. All the deposited films were amorphous. With the complexing agents, the thickness was increased, and the oxygen content was reduced significantly compared with the sample deposited without the complexing agents. In the photoelectrochemical measurement, p-type conductivity was confirmed. The photoresponsivity was not influenced significantly by the complexing agent, suggesting that the oxygen content does not drastically affect the properties of the deposited films probably because the local bonding configuration around Fe atoms in FeS x O y is similar to that in FeS2.

  19. Resistive humidity sensor based on vanadium complex films

    A resistive-type relative humidity (RH) sensor based on vanadium complex (VO2(3-fl)) film is reported in this study. Gold electrodes were deposited on the glass substrates in a co-planar structure. A thin film of vanadium complex was coated as a humidity-sensing material on the top of the pre-patterned electrodes. The humidity-sensing principle of the sensor was based on the conductivity change of coated sensing element upon adsorption/desorption of water vapor. The resistance of the humidity sensor measured at 1 kHz decreased linearly with increasing the humidity in the range of 35%–70% RH. The overall resistance of the sensor decreases 11 times. An equivalent circuit for the VO2(3-fl) based resistive-type humidity sensor was developed. The properties of the sensor studied in this work make it beneficial for use in the instruments for environmental monitoring of humidity. (semiconductor devices)

  20. Electropolymerized Molecularly Imprinted Polypyrrole Film for Sensing of Clofibric Acid

    Bianca Schweiger

    2015-02-01

    Full Text Available Piezoelectric quartz crystals and analogous gold substrates were electrochemically coated with molecularly imprinted polypyrrole films for pulsed amperometric detection (PAD of clofibric acid, a metabolite of clofibrate. Cyclic voltammetry data obtained during polymerization and deposited weight estimations revealed a decrease of the polymerization rate with increasing clofibric acid concentration. XPS measurements indicated that clofibric acid could be removed after imprinting with an aqueous ethanol solution, which was further optimized by using PAD. Zeta potential and contact angle measurements revealed differences between molecularly imprinted (MIP and non-imprinted polymer (NIP layers. Binding experiments with clofibric acid and other substances showed a pronounced selectivity of the MIP for clofibric acid vs. carbamazepine, but the response of MIP and NIP to 2,4-dichlorophenoxyacetic acid was higher than that for clofibric acid. A smooth surface, revealed by AFM measurements, with roughness of 6–8 nm for imprinted and non-imprinted layers, might be a reason for an excessively low density of specific binding sites for clofibric acid. Furthermore, the decreased polymerization rate in the presence of clofibric acid might not result in well-defined polymer structures, which could be the reason for the lower sensitivity.

  1. Deoxyribonucleic acid-based hybrid thin films for potential application as high energy density capacitors

    Joyce, Donna M.; Venkat, Narayanan; Ouchen, Fahima; Singh, Kristi M.; Smith, Steven R.; Grabowski, Christopher A.; Terry Murray, P.; Grote, James G.

    2014-03-01

    Deoxyribonucleic acid (DNA) based hybrid films incorporating sol-gel-derived ceramics have shown strong promise as insulating dielectrics for high voltage capacitor applications. Our studies of DNA-CTMA (cetyltrimethylammonium) complex/sol-gel ceramic hybrid thin film devices have demonstrated reproducibility and stability in temperature- and frequency-dependent dielectric properties with dielectric constant k ˜ 5.0 (1 kHz), as well as reliability in DC voltage breakdown measurements, attaining values consistently in the range of 300-350 V/μm. The electrical/dielectric characteristics of DNA-CTMA films with sol-gel-derived ceramics were examined to determine the critical energy storage parameters such as voltage breakdown and dielectric constant.

  2. Chemodynamics of soft nanoparticulate complexes: Cu(II) and Ni(II) complexes with fulvic acids and aquatic humic acids

    Town, R.M.; Leeuwen, van H.P.; Buffle, J.

    2012-01-01

    The dynamics of metal complexation by small humic substances (fulvic acid and aquatic humic acid, collectively denoted as "fulvic-like substance", FS) are explored within the framework of concepts recently developed for soft nanoparticulate complexants. From a comprehensive collection of published e

  3. Surface Functionalization of Hyaluronic Acid Hydrogels by Polyelectrolyte Multilayer Films

    Yamanlar, Seda; Sant, Shilpa; Boudou, Thomas; Picart, Catherine; Khademhosseini, Ali

    2011-01-01

    Hyaluronic acid (HA), an anionic polysaccharide, is one of the major components of the natural extracellular matrix (ECM). Although HA has been widely used for tissue engineering applications, it does not support cell attachment and spreading and needs chemical modification to support cellular adhesion. Here, we present a simple approach to functionalize photocrosslinked HA hydrogels by deposition of poly(L-lysine) (PLL) and HA multilayer films made by the layer-by-layer (LbL) technique. PLL/...

  4. Light amplification in dye-doped DNA-surfactant complex films

    Kawabe, Yutaka; Wang, Lili; Koyama, T.; Horinouchi, Suguru; Ogata, Naoya

    2000-11-01

    We observed amplified spontaneous emission (laser action without cavities) from several kinds of dyes doped in films of salmon DNA (deoxyribonucleic acid) derivatives. We employed laser dye Rhodamine-6G, Pyrromethene 556, and nonlinear optical dye DMASDPB for dopants. Most of sample films with several micrometers thickness were prepared as follows: 1) DNA aqueous solution was mixed with hexadecyltrimethylammonium chloride aqueous solution. 2) precipitated DNA-lipid complex and dyes were dissolved in ethanol or chloroform. 3) Films were formed on substrates by casting from the solution. The amplified spontaneous emission was observed when the films were pumped with a nanosecond laser of 532 nm at the intensity above a threshold value. Spectral narrowing occurred at the threshold energy, and it was accompanied with superlinear dependence of the emission intensity on the pumping intensity. Dye molecules in DNA films can be intercalated in the double helix structure. Because molecules are separated form one another, it is possible to increase chromophore concentration without fluorescence quenching due to aggregation. Furthermore, it is known that DNA shows a good conducting property. We will discuss the possibility of optical and electronic devices utilizing these characteristics.

  5. Complexes of low oxidated /sup 99/Tc with salicylic acid

    While several complexes of technetium with hydroxycarboxylic acids in solution are well known, little has been done about complexes of technetium with phenolcarboxylic acids. M.A. Kayssi suggested the use of sulphosalicylic acid as a reagent for the quantitative determination of technetium. The resulting complex shows a spectrophotometric maximum at 460 nm; the author supposes that the complex could contain technetium in the (V) oxidation state. In this paper the reaction between technetium and salicylic acid at concentrations between 10/sup -4/ and 5 x 10/sup -2/ M, in a pH range of 2 to 4.5, has been studied. The pH does not seem to influence the reaction, while the salicylic acid concentration is particularly significant

  6. Photodissociation spectroscopy of the Mg+-acetic acid complex

    We have studied the structure and photodissociation of Mg+-acetic acid clusters. Ab initio calculations suggest four relatively strongly bound ground state isomers for the [MgC2H4O2]+ complex. These isomers include the cis and trans forms of the Mg+-acetic acid association complex with Mg+ bonded to the carbonyl O atom of acetic acid, the Mg+-acetic acid association complex with Mg+ bonded to the hydroxyl O atom of acetic acid, or to a Mg+-ethenediol association complex. Photodissociation through the Mg+-based 3p+, MgOH+, Mg(H2O)+, CH3CO+, and MgCH3+. At low energies the dominant reactive quenching pathway is through dehydration to Mg(H2O)+, but additional reaction channels involving C-H and C-C bond activation are also open at higher energies

  7. Flotation extraction of rhodanide indium complexes from acidic solutions

    Principle possibility of flotation extraction of indium rhodanide complexes from acid solutions (H2SO4, HCl, HBr, HF, HNO3, HI, H3PO4, CH3COOH, HClO4) is shown. Optimum conditions for their extraction are created in the range of moderate (0.01-0.1 g-eq./l acid in solution) acidity when using quaternary compounds, containing from 13 to 18 carbon atoms in the alkyl part as collectors. It is established experimentally that indium is extracted from weakly acidic solutions in the form of mixed complex anions according to ion exchange mechanism, from strong acidic ones - mainly in the form of acid complexes similar to addition reactions

  8. Studies On Some Acid Divalent-Metal Nitrilotriacetate Complexes

    N. E. Milad

    2000-10-01

    Full Text Available IR and 1H-NMR studies on nitrilotriacetic acid (H3NTA suggest that the acid exists in the zwitterion form, which allows the existence of intermolecular hydrogen bonding. A tetrahedral structure is established for eleven (1:1 anhydrous acid-metal (II nitrilotriacetates complexes. The ten Dq values for the colored complexes were determined spectrophotometrically. The pKa values for the eleven acid metal complexes [M(HNTA].(OH23] were determined and compared with the corresponding pKa values of the [M(OH2n]+2 ions and also with the log β1 values of the corresponding [M(NTA]- complexes. X-ray diffraction studies on the ligand and on eight of these complexes are described.

  9. Formation of linear polyenes in poly(vinyl alcohol) films catalyzed by phosphotungstic acid, aluminum chloride, and hydrochloric acid

    Tretinnikov, O. N.; Sushko, N. I.; Malyi, A. B.

    2016-07-01

    Formation of linear polyenes-(CH=CH)n-via acid-catalyzed thermal dehydration of polyvinyl alcohol in 9- to 40-µm-thick films of this polymer containing hydrochloric acid, aluminum chloride, and phosphotungstic acid as dehydration catalysts was studied by electronic absorption spectroscopy. The concentration of long-chain ( n ≥ 8) polyenes in films containing phosphotungstic acid is found to monotonically increase with the duration of thermal treatment of films, although the kinetics of this process is independent of film thickness. In films containing hydrochloric acid and aluminum chloride, the formation rate of polyenes with n ≥ 8 rapidly drops as film thickness decreases and the annealing time increases. As a result, at a film thickness of less than 10-12 µm, long-chain polyenes are not formed at all in these films no matter how long thermal duration is. The reason for this behavior is that hydrochloric acid catalyzing polymer dehydration in these films evaporates from the films during thermal treatment, the evaporation rate inversely depending on film thickness.

  10. Starch-lipid complexes: Interesting material and applications from amylose-fatty acid salt inclusion complexes

    Aqueous slurries of high amylose starch can be steam jet cooked and blended with aqueous solutions of fatty acid salts to generate materials that contain inclusion complexes between amylose and the fatty acid salt. These complexes are simply prepared on large scale using commercially available steam...

  11. Characterization and complexation of humic acids. Part 1

    This paper summarizes the research contributions to the CEC Mirage II project, particularly the research area on complexation and colloids (COCO). The first part of the paper comprises the characterization of humic and fulvic acids from different origins: a commercial product from the Aldrich Co. used as a reference humic acid and site-specific humic acids from Gorleben (Germany), Boom Clay (Belgium) and Fanay Augeres (France) aquifer systems. The second part includes the complexation of trivalent actinides: Am(III) and Cm(III) with various humic acids. A number of different methods have been applied for the complexation study: spectrophotometry, ultrafiltration, laser-induced photo-acoustic spectroscopy (LPAS) and time-resolved laser fluorescence spectroscopy (TRLFS). The evaluation process of complexation constant is discussed extensively and the well consolidated results are presented, which can be directly used for the geochemical modelling of the radionuclide migration

  12. Development of pectin films with pomegranate juice and citric acid.

    Azeredo, Henriette M C; Morrugares-Carmona, Rosario; Wellner, Nikolaus; Cross, Kathryn; Bajka, Balazs; Waldron, Keith W

    2016-05-01

    The influence of pomegranate juice (PJ, replacing water as solvent) and citric acid (CA) on properties of pectin films was studied. PJ provided the films with a bright red color, and acted as a plasticizer. Increasing PJ/water ratio from 0/100 to 100/0 resulted in enhanced elongation (from 2% to 20%), decreased strength (from 10 to <2 MPa) and modulus (from 93 to <10 MPa), increased water vapor permeability (WVP, from 3 to 9 g.mm.kPa(-1).h(-1).m(-2)), and decreased insoluble matter (IM, from 35% to 24%). Although a crosslinking effect by CA was not confirmed, it has been suggested to occur from its effects on films. CA noticeably increased IM (from <10% to almost 40%); moreover, when measured on a dry film basis, the CA effects presented a noticeable tendency to increases strength and modulus, and to decrease WVP. The red color density was decreased by CA, suggesting a destabilization of anthocyanins. PMID:26769510

  13. Bioinspired lubricating films of cellulose nanofibrils and hyaluronic acid.

    Valle-Delgado, Juan José; Johansson, Leena-Sisko; Österberg, Monika

    2016-02-01

    The development of materials that combine the excellent mechanical strength of cellulose nanofibrils (CNF) with the lubricating properties of hyaluronic acid (HA) is a new, promising approach to cartilage implants not explored so far. A simple, solvent-free method to produce a very lubricating, strong cellulosic material by covalently attaching HA to the surface of CNF films is described in this work. A detailed analysis of the tribological properties of the CNF films with and without HA is also presented. Surface and friction forces at micro/nanoscale between model hard surfaces (glass microspheres) and the CNF thin films were measured using an atomic force microscope and the colloid probe technique. The effect of HA attachment, the pH and the ionic strength of the aqueous medium on the forces was examined. Excellent lubrication was observed for CNF films with HA attached in conditions where the HA layer was highly hydrated. These results pave the way for the development of new nanocellulose-based materials with good lubrication properties that could be used in biomedical applications. PMID:26674836

  14. Investigation of neodymium complexes with hydroxyethyliminodiacetic acid by spectrography

    The electron absorption spectra of NdCl3 solution in the presence of oxyethylimidinodiacetic acid (H2L) in a wide range of pH (1.35-11) were studied. It is shown by the isomolar series method that neodymium forms mono-, di- and sesquialteral complexes with H2L. The absorption spectra of the corresponding solid and dissolved complexes of neodymium with oxyethyliminodiacetic acid were investigated

  15. Visible Absorption Properties of Retinoic Acid Controlled on Hydrogenated Amorphous Silicon Thin Film

    Tsujiuchi, Yutaka; Masumoto, Hiroshi; Goto, Takashi

    2008-02-01

    Langmuir-Blodgett (LB) films of retinoic acid and LB films of retinoic acid mixed with a peptide that contains an alanine-lysine-valine (AKV) amino acid sequence deposited on a hydrogenated amorphous silicon (a-Si:H) film prepared by electron cyclotron resonance (ECR) plasma sputtering were fabricated, and their light absorption spectrums were compared. A specific visible light absorption at approximately 500 nm occurred in a film that had a film thickness of more than 80 nm and a hydrogen concentration of more than 20% in the sputtering process gas. Mixing the AKV sequence peptide with retinoic acid caused a 6 nm blueshift, from 363 to 357 nm, of the absorption maximum of the composite LB film on a SiO2 substrate. Using the same peptide, a large 30 nm blueshift, from 500 to 470 nm, was induced in the composite LB film on the a-Si:H film.

  16. Stability constant of the lanthanum complex with humic acid

    The work described here is a study on the formation of trivalent lanthanum complex with humic acid. Commercial humic acid was purified and then characterized by various analytical techniques. The stability constant determined by a radiochemical method has a worth of log βLa,AHA = 13.6. (Author)

  17. Composition of nitrosyl ruthenium complexes in nitric acid

    The composition of nitrosyl ruthenium complexes in nitric acid has been determined. The analysis was carried out by low temperature, gradient elution, reversed-phase partition chromatography. Paper chromatography, using methyl isopropyl ketone and nitric acid-acetone, were also carried out to obtain complementary data. (author)

  18. Anisotropy and micromagnetics in complex oxide thin films

    Wynn, Thomas Andrew

    Complex oxide perovskites are a class of material with a remarkably wide range of functional properties including magnetism, superconductivity, metal-to-insulator transitions, colossal magnetoresistance, and in some cases high magnetocrystalline anisotropy. Reduction in length scales through thin film deposition and nanopatterning results in altered properties from their bulk constituents. In this work, thin films of La0.7Sr0.3CoO3 (LSCO) and LSCO/La 0.7Sr0.3MnO3 (LSMO) bilayers of varying thicknesses were deposited onto (LaAlO3)0.3(Sr2TaAlO 6)0.7 (LSAT) substrates, and their anisotropic magnetic properties were measured along the in- plane [100] and [110] directions using superconducting quantum interference device (SQUID) magnetometry and soft x-ray magnetic spectroscopy. The LSCO showed thickness dependent magnetism, and films were non-magnetic below a critical thickness of 4 nm. Magnetic LSCO films showed unique anisotropic effects on the saturation magnetization (Ms), with a lower M s in the [110] direction than the [100] direction. This potentially indicates the existence of a hard component in the [110] direction that is not being switched at fields in the SQUID magnetometer (7 T). Normalized hysteresis loops indicate the LSCO films display little magnetocrystalline anisotropy within the plane of the film. LSCO/LSMO bilayers with a fixed LSMO layer of 6 nm in thickness showed cobalt magnetism at thicknesses where single layers were non-magnetic, suggesting that the substrate/film interface is not the cause of the non-magnetic layer in the LSCO thin films. Magnetic coupling occurs in bilayers with LSCO layer thicknesses of below 4 nm, and both LSCO and LSMO layers showed a [110] easy axis. When the layer thickness of LSCO was increased above 8 nm, the LSCO layer developed a soft component at the LSCO/LSMO interface. This soft LSCO component remained coupled with the LSMO, though the easy axis changed to the [100] direction, and the harder, non-interface LSCO

  19. Uranyl complexes of n-alkanediaminotetra-acetic acids

    The uranyl complexes of n-propanediaminetetra-acetic acid, n-butanediaminetetra-acetic acid and n-hexanediaminetetra-acetic acid have been studied by potentiometry, with computer evaluation of the titration data by the MINIQUAD program. Stability constants of the 1:1 and 2:1 metal:ligand chelates have been determined as well as the respective hydrolysis and polymerization constants at 25 deg in 0.10M and 1.00M KNO3. The influence of the length of the alkane chain of the ligands on the complexes formed is discussed. (author)

  20. Protection of NdFeB magnets by corrosion resistance phytic acid conversion film

    Nan, Haiyang; Zhu, Liqun; Liu, Huicong; Li, Weiping

    2015-11-01

    Phytic acid conversion film was prepared on NdFeB magnets by dipping the NdFeB into phytic acid solution. The morphology, composition, structure and corrosion resistance of the film were systematically investigated. The results showed that the phytic acid film was effective in improving the corrosion resistance of NdFeB magnets. XRD, TEM and FT-IR analyses revealed that the film was amorphous and had a strong peak of phosphate radical (PO43-). The formation mechanism of the film was also explored by XPS and the potential of zero charge (Epzc) measurement at the solution-metal interface.

  1. Investigation into neodymium complexes with methylmalonic acid by spectrography

    Complexes of neodymium with methylmalonic acid have been studied spectrographically. It has been shown that aquoion and three dimeric complexes of the composition approximately 1:1 coexist in the pH region 3.5-6.5 when the ratio between the components is equimolar. When there is an excess of the ligand, polymeric complexes of the composition 1:2 are found in the solution in addition to the complexes 1:1. The stability constants of the complexes have been determined and the data on their structure have been obtained

  2. Synthesis and characterization of acidic mesoporous borosilicate thin films.

    Xiu, Tongping; Liu, Qian; Wang, Jiacheng

    2009-02-01

    Work on the synthesis and characterization of acidic wormhole-like ordered mesoporous borosilicate thin films (MBSTFs) on silicon wafers is described in this paper. The MBSTFs coated by the dip-coating method were prepared through an evaporation-induced self-assembly (EISA) process using nonionic block copolymers as structure-directing agents. Fourier transform infrared (FT-IR) spectroscopy confirmed the formation of borosiloxane bonds (Si-O-B). High-resolution transmission electron microscopy (HRTEM) and N2 sorption evidenced a wormhole-like mesoporous structure in the MBSTFs obtained. Scanning electron microscopy (SEM) images of the cross sections and surfaces of the samples showed that MBSTFs on silicon wafers were continuous, homogeneous and did not crack. The acidic properties of the MBSTFs were characterized by FT-IR spectra of chemisorbed pyridine. The MBSTFs thus prepared may find their future applications in many fields including chemical sensors, catalysis, optical coating, molecule separation, etc. PMID:19441565

  3. Acrylic acid obtaining from methanol and acetic acid in the presence of complex oxide catalysts

    Небесний, Роман Володимирович; Піх, Зорян Григорович; Шпирка, Ірина Іванівна; Івасів, Володимир Васильович; Небесна, Юлія Віталіївна; Фуч, Уляна Василівна

    2015-01-01

    The purpose of this work is to research process of single-stage acrylic acid obtaining from methanol and acetic acid, namely: to develop effective catalysts for the process of methanol oxidation to formaldehyde with its further aldol condensation with acetic acid to acrylic acid, and to determine optimum conditions for the process. Complex oxide catalysts consisting of oxides of boron, phosphorus, tungsten and vanadium supported on the silica gel have been investigated. The effect of vanadium...

  4. Radiation grafting of acrylic acid onto polypropylene films

    A study has been made for the preparation of membranes by the direct radiation grafting of acrylic acid (AAc) onto polypropylene (PP) films. The appropriate reaction conditions were selected under which the graft polymerization was carried out successfully. The effect of different solvents such as benzene, methanol/water mixture, isopropanol/water mixture, dimethyl formamide and distilled water on the swelling and grafting process of AAc onto PP films was investigated. In this grafting system ammonium ferrous sulphate (Mohr's salt) and ferric chloride were used as inhibitors to minimize the homopolymerisation of AAc and the suitable concentration of the inhibitor was found to be 1.0 and 1.5 wt% for Mohr's salt and ferric chloride, respectively. Also, the effect of monomer concentration on the rate of grafting was investigated. The dependence of the grafting rate on monomer concentration was found to be 1.1 order. This grafting system proceeded by diffusion controlled process. Some selected properties of the grafted films such as swelling behaviour, gel determination, mechanical and electrical properties were also investigated. It was found that the grafted membranes possess good hydrophilic properties which may make them promising in some practical applications. (author)

  5. Laser-induced damage of sol-gel silica acid and basic thin films

    The sol-gel monolayer silica acid and basic thin films on K9 glass substrates were prepared with the dip method from acid and basic catalyzed silica sols, respectively. Both films have nearly similar optical thickness. The laser-induced damage thresholds(LIDT) of the two kinds of films were measured. Thermal absorption, porous ratio and surface morphologies of films were investigated by Stanford photo-thermal solutions, ellipsometer, atomic force microscope(AFM) and scanning electron micro-scope(SEM), respectively. Optical microscope was used to characterize the defects and impurities of films before laser irradiation and damage morphology after laser irradiation. The experimental results showed that compared with basic film, the silica acid film had larger absorption, smaller porous ratio, and smaller LIDT. Different damage morphologies of films were relative to their different absorption and microstructures. (authors)

  6. Photoconductivity study of acid on Zinc phthalocyanine pyridine thin films

    Singh, Sukhwinder; Saini, G. S. S.; Tripathi, S. K.

    2016-05-01

    The Metal Phthalocyanine (MPc) have attracted much interest because of chemical and high thermal stability. Molecules forming a crystal of MPc are held together by weak attractive Vander Waals forces. Organic semiconductors have π conjugate bonds which allow electrons to move via π-electron cloud overlaps. Conduction mechanisms for organic semiconductor are mainly through tunneling; hopping between localized states, mobility gaps, and phonon assisted hopping. The photo conductivity of thin films of these complexes changes when exposed to oxidizing and reducing gases. Arrhenius plot is used to find the thermal activation energy in the intrinsic region and impurity scattering region. Arrhenius plotsare used to find the thermal activation energy.

  7. Novel silk fibroin films prepared by formic acid/hydroxyapatite dissolution method

    Bombyx mori silk fibroin from the silkworm was firstly found to be soluble in formic acid/hydroxyapatite system. The rheological behavior of silk fibroin solution was significantly influenced by HAp contents in dissolved solution. At the same time, silk fibroin nanofibers were observed in dissolved solution with 103.6 ± 20.4 nm in diameter. Moreover, the structure behavior of SF films prepared by formic acid/hydroxyapatite dissolution method was examined. The secondary structure of silk fibroin films was attributed to silk II structure (β-sheet), indicating that the hydroxyapatite contents in dissolved solution were not significantly affected by the structure of silk fibroin. The X-ray diffraction results exhibited obviously hydroxyapatite crystalline nature existing in silk fibroin films; however, when the hydroxyapatite content was 5.0 wt.% in dissolved solution, some hydroxyapatite crystals were converted to calcium hydrogen phosphate dehydrate in silk fibroin dissolution process. This result was also confirmed by Fourier transform infrared analysis and DSC measurement. In addition, silk fibroin films prepared by this dissolution method had higher breaking strength and extension at break. Based on these analyses, an understanding of novel SF dissolution method may provide an additional tool for designing and synthesizing advanced materials with more complex structures, which should be helpful in different fields, including biomaterial applications. - Highlights: • SF fibers were firstly successfully dissolved in FA/HAp solution. • The rheological behavior of SF solution was significantly influenced by HAp contents. • SF nanofibrils were observed in FA/HAp solution with 103.6 ± 20.4 nm in diameter. • SF films prepared by FA/HAp dissolution method had higher mechanical properties

  8. Complex forming properties of natural organic acids. Pt. 2

    An ultrafiltration technique combined with ion-selective-electrode and atomic absorption methods have been employed to obtain information on the complex forming properties of fulvic acid with iron and calcium. A model for interpreting complexation of metal ions to fulvic acid at any pH, medium ionic strength and metal to fulvic acid ratio developed earlier has been used in an attempt to predict the nature of iron and calcium interaction to Armadale Horizon Bh fulvic acid. Binding of calcium to fulvic acid which is enhanced at pHs greater than 6.0 has reasonably been predicted by the model taking into consideration complications due to the polyelectrolyte nature and the heterogeneity of the fulvic acid. The lack of agreement observed between the model predicted binding behavior and the experimentally observed results for the fulvic acid-iron system has been attributed to the formation of metal-induced aggregation. Reduction of Fe(III) to Fe(II) by the fulvic acid as reported by other workers is corroborated. (orig.)

  9. NMR studies of the complexes of uramildiacetic acid

    Proton spectra of 1,3 dimethyluramildiacetic acid and its complexes with several lanthanide ions as well as titration curves of uramildiacetic and barbituric acids where 13C chemical shifts were followed as a function of pH, have enabled the establishment of the conformation in solution of the complexes of the uramildiacetate-type ligands and of the most probable mechanism of ionization of these compounds. It is definitely shown that uramildiacetic acid is tetradentate and that it coordinates to metal ions through the iminodiacetate group and one of the carboxyl groups in position 4,6 of the molecule. The pyrimidinic ring and one of the chelator rings are coplanar and the complexes have axial symmetry. (author)

  10. Phase Chemistry of the Complexes of RE Amino Acids

    2002-01-01

    Forty-three phase diagrams of ternary system concerning rare earth salts, α-amino acids and water, which were constructed by phase equilibrium methods, were expounded. The influences of the factors such as cations, anions, the structure of amino acids, temperature on the phase diagrams were discussed. Under the guidance of phase equilibrium results, over 150 new solid complexes were prepared. IR, reflecting, UV, FS, and Raman spectra for these complexes were investigated and the regularity of “tripartite effect”, “tetrad effect”, “Nephelanxetic effect”, “Oddo-Harkins” was observed. Thermal decomposition processes of the complexes were confirmed. Based on the comparison with the known crystal structures of rare earth-amino acid-complexes, an estimation method for predicting the crystal structure data of series complexes was founded. The constant volume combustion energies of the complexes were determined by RBC-1 type rotating bomb calorimeter. The standard enthalpies of combustion and standard enthalpies of formation were calculated for these complexes.

  11. The Effects of plasticizers and palmitic acid toward the properties of the carrageenan Film

    Heru Wibowo, Atmanto; Listiyawati, Oktaviana; Purnawan, Candra

    2016-02-01

    Varied plasticizers and palmitic acid additive have been added in the carrageenan film. The film was made by mixing of the carrageenan and plasticizers (glycerol, polyethylene glycol, polyvinyl alcohol) with composition of 92:3, 90:6, 87:9, 84:12, 81:15(%w/w) and in the presence of palmitic acid as additive with 1%, 2%, 3%, 4%, 5% of total weight. Casting method was used for the film molding and drying at 60oC with the oven for 12 hours. To investigate the effects of plasticizers and additive, some mechanical tests on film were performed. The test result concludes that plasticizers in the film decreased the tensile strength and increased the elongation break of the carrageenan film. The additive of palmitic acid decreased the tensile strength of the carrageenan film and also decreased the-the water absorbance of the film. The highest tensile strength of films made was with the formulation of carrageenan: PEG with composition of 92:3 (% w/w). The highest elongation break of the film was for carrageenan:PVA with the composition of 81: 15 (%w/w) and carrageenan:palmitic acid:PEG with the composition of 92: 3: 1 (%w/w). The lowest water absorption of the film was achieved for carrageenan:PVA:palmitic acid with the composition of 87: 3: 5 (%w/w).

  12. Analyzing Freud's Oedipus Complex from the Perspective of the Films of Hamlet%Analyzing Freud's Oedipus Complex from the Perspective of the Films of Hamlet

    吴静

    2012-01-01

    Freud's Oedipus complex has an important influence on the performance of Shakespeare's Hamlet. Analyzing Freud's Oedipus complex from a visual perspective, which helps understand Hamlet's suffering from oedipal conflicts more easily and visibly. This paper mainly focuses on two popular films. One is the most classical, the black-and-white film produced, directed and starred by Laurence Oliver in 1948. with Eileen Heritee as Gertude. The other is the PBS version of 2010, lasting nearly three hours, directed by Gregory Doran.

  13. Antimicrobial activity of nisin incorporated in pectin and polylactic acid composite films against Listeria monocytogenes

    Extruded composite films from 20% pectin and 80% polylactic acids (PLA) were developed and nisin was loaded into films by a diffusion post extrusion. Inhibitory activities of the films against Listeria monocytogenes were evaluated in brain heart infusion (BHI) broth, liquid egg white and orange juic...

  14. Formation constants of mixed ligand complexes of oxovanadium(IV) with salicylic acid/5-sulphosalicylic acid/8-hydroxyquinoline-5-sulphonic acid and hippuric acid

    Equilibrium studies are described on the interaction of oxovanadium(IV) with salicylic acid (SA)/5-sulphosalicylic acid (SSA)/8-hydroxyquinoline-5-sulphonic acid (HQSA) in presence of hippuric acid. The formation of 1:1:1 mixed ligand complexes and their hydroxo derivatives inferred from the pH-metric titration curves and formation constants of 1:1:1 ternary complexes have been evaluated at 30 +- 0.5deg (μ = 0.1 M KNO3). The order of stability of ternary complexes has been found to be the same as that of 1:1 binary complexes involving hydroxy acids. (author)

  15. Facile method to prepare silk fibroin/hyaluronic acid films for vascular endothelial growth factor release.

    Zhou, Juan; Zhang, Bin; Liu, Xunwei; Shi, Lijun; Zhu, Jun; Wei, Daixu; Zhong, Jian; Sun, Gang; He, Dannong

    2016-06-01

    A facile approach was proposed to prepare silk fibroin (SF) and hyaluronic acid (HA) composite films from aqueous solution without crosslinking or any post treatment. Only by controlling the HA content and film formation temperature during the film casting, the HA/SF films with different composition were prepared. The films were then characterized by structural characteristics, thermal stability, morphology, water stability, water absorption, mechanical properties. After immersing in water for 24h, all of the films showed good structural integrity. The degradation rate of the HA/SF films in protease XIV can be controlled by changing the film formation temperature and HA content. Decreasing the temperature and adding HA resulted in the rapid release of VEGF (vascular endothelial growth factor) from the HA/SF films. Overall, the 5% HA/SF films formed at 37°C with more rapid VEGF release exhibited great potential in drug delivery, especially when the rapid vascularization was needed. PMID:27083373

  16. Spectrographic investigation of neodymium complexing with hexamethylenediaminetetraacetic acid

    Complex formation between neodymium and hexamethylenediamine-tetraacetic acid (HMTA, H2L) in aqueous solution has been studied by high-resolution spectrography. Formation of NdHL, Hd(HL)23-, Nd(HL)36- complexes has been proved, their values of formation constants (lg Csub(form)) being equal to 5.63+-0.45, 4.20+-0.15, 2.63+-0.15, respectively

  17. Effects of swelling on the viscoelastic properties of polyester films made from glycerol and glutaric acid

    Viscoelastic properties have been determined for poly(glycerol-co-glutaric acid) films synthesized from Lewis acid-catalyzed polyesterifications. The polymers were prepared by synthesizing polymer gels that were subsequently cured at 125 degrees C to form polymer films. The polymers were evaluated ...

  18. A multivariant study of the absorption properties of poly(glutaric-acid-glycerol) films

    The solvent absorption into the matrix of poly(glutaric acid-glycerol) films made with or without either iminodiacetic acid, sugarcane bagasse, pectin, corn fiber gum or microcrystalline cellulose have been evaluated. The films were incubated in various solvent systems for 24h. The amounts of solve...

  19. Polypyrrole-polyvinyl sulphonate film based disposable nucleic acid biosensor

    Prabhakar, Nirmal [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Centre for Biomedical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Arora, Kavita [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Singh, Surinder P. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Pandey, Manoj K. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Singh, Harpal [Centre for Biomedical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Malhotra, Bansi D. [Biomolecular Electronics and Conducting Polymer Research Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India)]. E-mail: bansi.malhotra@gmail.com

    2007-04-18

    Double stranded calf thymus deoxyribonucleic acid entrapped polypyrrole-polyvinyl sulphonate (dsCT-DNA-PPy-PVS) films fabricated onto indium-tin-oxide (ITO) coated glass plates have been used to detect organophosphates such as chlorpyrifos and malathion. These disposable dsCT-DNA-PPy-PVS/ITO bioelectrodes have been characterized using cyclic voltammetry, Fourier-transform-infra-red (FTIR) spectroscopy and atomic force microscopy (AFM), respectively. These biosensing electrodes have a response time of 30 s, are stable for about 5 months when stored in desiccated conditions at 25 deg. C and can be used to amperometrically detect chlorpyrifos (0.0016-0.025 ppm) and malathion (0.17-5.0), respectively. The additive effect of these pesticides on the amperometric response of the disposable dsCT-DNA-PPy-PVS/ITO bioelectrodes has also been investigated.

  20. Impact of acid and oxidative modifications, single or dual, of sorghum starch on biodegradable films.

    Biduski, Bárbara; Silva, Francine Tavares da; Silva, Wyller Max da; Halal, Shanise Lisie de Mello El; Pinto, Vania Zanella; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-01-01

    The objective of this study was to evaluate the effects of acid and oxidation modifications on sorghum starch, as well as the effect of dual modification of starch on the physical, morphological, mechanical, and barrier properties of biodegradable films. The acid modification was performed with 3% lactic acid and the oxidation was performed with 1.5% active chlorine. For dual modification, the acid modification was performed first, followed by oxidation under the same conditions as above. Both films of the oxidized starches, single and dual, had increased stiffness, providing a higher tensile strength and lower elongation when compared to films based on native and single acid modified starches. However, the dual modification increased the water vapor permeability of the films without changing their solubility. The increase in sorghum starch concentration in the filmogenic solution increased the thickness, water vapor permeability, and elongation of the films. PMID:27507447

  1. Diffusion coefficients of metals and metal complexes in hydrogels used in diffusive gradients in thin films

    Diffusion coefficients of metal ions and metal-ligand complexes in hydrogels were measured at ionic strengths of 0.1-100 mmol L-1 using a diffusion cell. The three different types of hydrogel were all based on polyacrylamide and have been commonly used in the technique of diffusive gradients in thin films (DGT), where accurate diffusion coefficients are essential for the assessment of the concentrations of labile metal in solution. There was little difference in the diffusion coefficients of either Cu and Cd measured in gels with thicknesses of 0.4, 0.8 and 1.6 mm, showing that any diffusion boundary layer in solution was negligibly small. The diffusion coefficients of Pb, Ni, Cu and Cd in simple inorganic solutions was independent of ionic strength (1-100 mmol L-1), except at very low ionic strengths (0.1 mmol L-1) where the value of D was 50% lower. This observation is consistent with the gel having a positive charge that creates a Donnan partitioning of cations at the gel surface. Diffusion coefficient of Pb complexes decreased with increasing size of the ligand, in the order of diglycolic acid (DGA), nitrilotriacetic acid (NTA), fulvic acid and humic acid. In freshwaters the contribution of fulvic acid species to measured DGT mass should be considered. No significant difference was found between the rate of diffusion of Cu and Cd through the mostly commonly used gel and the filter membrane at the face of the DGT device. Diffusion coefficients obtained using a gel with small pore size (restricted gel) plus filter membrane were higher than those obtained using the restricted gel alone. It may be necessary to modify the standard DGT equation for restricted gel deployments, to take into account the difference in diffusion between the gel and the filter membrane

  2. Effects of gas atmospheres on poly(lactic acid) film in acrylic acid plasma treatment

    Plasma polymerized acrylic acid (AA) coatings were deposited on poly(lactic acid) (PLA) films in various gas atmospheres during the pre-treatment of PLA and the deposition of AA, respectively. Therefore, this work was twofold: the argon pretreated PLA films followed by a deposition in argon were investigated against the mixture of argon and oxygen pretreated ones under the same deposition conditions; the plasma deposition of AA operating in different atmospheres (argon, oxygen and nitrogen) was employed to modify the pretreated PLA in oxygen. Chemical and physical changes on the plasma-treated surfaces were examined using contact angle, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and attenuated total reflection infrared (ATR-FTIR) analysis. The results showed that the discharge gas can have a significant influence on the chemical composition of the PLA surfaces: oxygen plasmas introduced oxygen-containing groups in company with surface etching in pretreatment and deposition, while argon discharges was able to achieve much better hydrophilic behavior and high retention ratio of poly(acrylic acid) (PAA) coating before and after washing in water.

  3. Effects of gas atmospheres on poly(lactic acid) film in acrylic acid plasma treatment

    Zhao, Yun, E-mail: yun.zhaotju@yahoo.com [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Fina, Alberto [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino – sede di Alessandria, V. T. Michel 5, 15121 Alessandria (Italy); Venturello, Alberto; Geobaldo, Francesco [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy)

    2013-10-15

    Plasma polymerized acrylic acid (AA) coatings were deposited on poly(lactic acid) (PLA) films in various gas atmospheres during the pre-treatment of PLA and the deposition of AA, respectively. Therefore, this work was twofold: the argon pretreated PLA films followed by a deposition in argon were investigated against the mixture of argon and oxygen pretreated ones under the same deposition conditions; the plasma deposition of AA operating in different atmospheres (argon, oxygen and nitrogen) was employed to modify the pretreated PLA in oxygen. Chemical and physical changes on the plasma-treated surfaces were examined using contact angle, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and attenuated total reflection infrared (ATR-FTIR) analysis. The results showed that the discharge gas can have a significant influence on the chemical composition of the PLA surfaces: oxygen plasmas introduced oxygen-containing groups in company with surface etching in pretreatment and deposition, while argon discharges was able to achieve much better hydrophilic behavior and high retention ratio of poly(acrylic acid) (PAA) coating before and after washing in water.

  4. Complexation of the uranyl ion with aquatic humic acid

    The complexation of the uranyl(VI) ion with aquatic humic acid from Gorleben groundwater (Gohy-573) is studied in 0.1 M NaClO4 at pH 4 under argon atmosphere. The concentration range investigated is from 1 x 10-7 to 1 x 10-5 mol/l for the uranyl ion and from 1 x 10-6 to 1.12 x 10-5 mol/l for the humic acid. Three different experimental methods are applied to separate the uncomplexed uranyl ion from the uranyl humate complex, using differences of the two species in size by ultrafiltration at the pore size of about 1 nm, in charge by anion exchange separation and in spectroscopic properties by time resolved laser fluorescence spectroscopy (TRLFS). No reduction of U(VI) to U(IV) is observed in the course of the humate complexation process. The experimental results confirm that the prevailing complexation reaction is charge neutralization of the UO2+2 ion with two proton exchanging sites of humic acid. At pH 4 in 0.1 M NaClO4, where the hydrolysis of the uranyl ion appears negligible, the fraction of proton exchanging sites of the humic acid that can be occupied by the uranyl ion (called the loading capacity (LC) of the uranyl ion) is determined to be 0.185±0.003. The complexation constant evaluated by taking the loading capacity into account is found to be logβ = 6.16±0.13, which is a grand average of all values determined by the three experimental procedures under consideration. This value is valid for the humate complexation of the non-hydrolyzed uranyl ion, being independent of pH and ionic strength. (orig.)

  5. Protactinium(V) complexation by oxalic and diethylenetriaminepentaacetic acids

    The present work is devoted to complexation of Pa(V) with oxalic acid and DTPA. Structural data on the limiting complex have been collected by combining X-ray absorption Spectroscopy, Capillary Electrophoresis (CE-ICP-MS) and DFT calculations. Thermodynamic data have been deduced from solvent extraction experiments. XAS data registered on samples of Pa(V) in oxalic acid have revealed the presence of one single Pa-O oxo bond and 3 oxalate in a bidentate mode in the complex of maximum order. The structure optimization, performed through DFT calculations indicate that 2 oxalate lie in the equatorial plane of the Pa=O bond, whereas one oxygen of the third oxalate goes in the prolongation of the oxo bond. Stability constants of the three successive complexes were determined by solvent extraction in the TTA/toluene/H2O/Pa(V)/NaClO4/HClO4/H2C2O4 system at different temperatures and 3M ionic strength. The stability of the complexes was proved to increase with their order. CE-ICP-MS measurements on Pa/DTPA samples have indicated the formation of a neutral (1:1)limiting complex. This complex can therefore be written as Pa(DTPA). The optimized structure determined by DFT calculations allowed one to conclude that all eight donor atoms (5 O and 3 N) of the DTPA ligand are involved in the coordination of protactinium. The formation constant of this complex has been determined for different values of ionic strength and temperature. The complexation reaction of Pa(V) with DTPA was proved to be entropy controlled. (author)

  6. Synthesis and properties of ZnS-EuS films grown from volatile complex compounds

    Bessergenev, V.G.; Ivanova, E.N.; Kovalevskaya, Y.A. [Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation). Inst. of Inorganic Chemistry

    1997-10-01

    Deposition and characterization of films of ZnS, EuS and ZnS:Eu are described. The films have been prepared by chemical vapor deposition using new volatile complex compounds, dithiocarbamates of Zn and Eu, as precursors. Characterization includes X-ray diffraction, chemical analysis of the film composition, Raman spectroscopy, ellipsometry, and spectrophotometry. The spatial chemical homogeneity of the films has been determined using a recently developed method of differential dissolution and found to be uniform. Doping of ZnS by Eu with dopant concentration up to 0.3 at.% has been achieved. Effects of Eu doping on structural and optical properties of the films are presented.

  7. Synthesis ZnS:Sm thin films from volatile complex compounds

    Ivanova, Elena N.; Kovalevskaya, Yu. A.; Bessreguenev, Valentin G.

    2002-11-01

    Deposition and characterization of ZnS, Sm2S3 and ZnS:Sm films are described. The films have been prepared by chemical vapor deposition using new volatile complex compounds, dithiocarbamates of Zn and Sm, as precursors. Characterization includes X-ray diffraction, chemical analysis of the film composition, ellipsometry and spectrophotometry. It has been shown that at relatively low temperatures (about 380 °C) monophase crystalline Sm2S3 films can be fabricated. Doping of ZnS by Sm with dopant concentration up to 2 at. % has been achieved. Effects of Sm doping on structural and optical properties of the film are presented.

  8. Introduction of phosphoric acid group to polypropylene film by radiation grafting and its blood compatibility

    2,3-epoxypropyl methacrylate (EPMA) was grafted to polypropylene (PP) film by using a radiation grafting technique. The phosphoric acid group was introduced to the EPMA-grafted PP films with different grafting yields. The blood compatibility of the phosphoric acid group-introduced PP films was evaluated by the determination of platelet adsorption and thrombus formation. The EPMA grafting extent was found to be dependent on the absorbed dose, reaction time and temperature. The grafting and phosphonation reactions were confirmed by Fourier transform infrared spectroscopy in the attenuated total reflectance mode and electron spectroscopy for chemical analysis. The amount of thrombus and adherent platelet on modified PP film was evaluated by an in vitro method and scanning electron microscope, respectively. The phosphoric acid group-introduced PP film was found to have good blood compatibility, which increased with the content of the introduced phosphoric acid group

  9. Effect of complexing agent on the photoelectrochemical properties of bath deposited CdS thin films

    In the present paper photoelectrochemical (PEC) performance of bath deposited CdS thin films based on complexing agents i.e. ammonia and triethanolamine (TEA) has been discussed. Effect of annealing has also been analyzed. The as-deposited and annealed (at 523 K for 1 h in air) films were characterized by X-ray diffraction (XRD), ultraviolet-visible (UV-vis) absorption spectroscopy, SEM, electrochemical impedance spectroscopy (EIS), and PEC properties. XRD studies revealed that the films were nanocrystalline in nature with mixed hexagonal and cubic phases. TEA complex resulted in better crystallinity. Further improvement in the crystallinity of the films was observed after air annealing. The marigold flower-like structure, in addition to flakes morphology, was observed with TEA complex, whereas for ammonia complex only flakes morphology was observed. The UV-vis absorption studies revealed that the optical absorption edge for the films with ammonia and TEA complex was around 475 nm and 500 nm, respectively. Annealing of the films resulted in red shift in the UV-vis absorption. The PEC cell performance of CdS films was found to be strongly affected by crystallinity and morphology of the films resulted due to complexing agent and annealing. The air annealed film deposited using TEA complex showed maximum short circuit current density (Jsc) and open circuit voltage (Voc) i.e. 99 μA/cm2 and 376 mV respectively, under 10 mW/cm2 of illumination. The films deposited using TEA complex showed good stability under PEC cell conditions.

  10. A study on antithrombogenic polymeric dialytic membrane. Irradiation grafting acrylic acid and styrene into polyethylene films

    A new type of antithrombogenic polymeric dialytic membrane with a hydrophilic-hydrophobic microphase structure was prepared by grafting acrylic acid and styrene into polyethylene films, using peroxidation pre-irradiation technique. Various ratios of monomers influencing on properties of the grafted films were examined. Experimental results showed that the grafted films have superior mechanic strength, and their antithrombogenicity and permeability were 30 and 10 times higher than that of the ungrafted films respectively on condition of the volume ratio 1:1 (styrene vs acrylic acid)

  11. The complexation behavior of neptunium and plutonium with nitrilotriacetic acid

    The first stability constant of NpO2+ with nitrilotriacetic acid (NTA) was determined at four ionic strengths (I = 0.5, 1.0, 2.0, 3.0 M) by using spectrophotometry. Nonlinear least-squares data fitting identified the complex as NpO2NTA2-. The specific ion interaction (SIT) theory approximation method was used to determine the stability constants at infinite dilution. In this paper first results on Pu4+ and PuO22+ complexation with NTA are reported. The stability constant for the Pu(NTA)+ complex at I = 0.1 M is given. From results for PuO22+ complexation with NTA (I = 1 M) at pH 2-NTA-. At pH > 3, NTA partially reduced PuO22+ to PuO2+

  12. Scandium and zirconium ion complexing with salicylic acid

    A study has been made of the extraction of complexes containing scandium and zirconium compounds and salicylic acid by using benzene, nitrobenzene, chloroform and isoamyl alcohol. It is shown that in the metal concentration range 10-5-10-3 mole/l scandium forms mononuclear complexes composed of Sc(HSal)3 (pH2 (pH>4), zirconium - polynuclear complexes Zrsub(x)(OH)sub(y)(HSal)sub(n), where the x:n ratio varies from 0.5 to 1.5. Stability constants have been calculated for the salicylate scandium complexes in aqueous solution, equal to β1=(3+-1)x102; β2=(5.0+-0.6)x104; β3=(5.3+-0.3)x106

  13. Pharmacology of bile acid receptors: Evolution of bile acids from simple detergents to complex signaling molecules.

    Copple, Bryan L; Li, Tiangang

    2016-02-01

    For many years, bile acids were thought to only function as detergents which solubilize fats and facilitate the uptake of fat-soluble vitamins in the intestine. Many early observations; however, demonstrated that bile acids regulate more complex processes, such as bile acids synthesis and immune cell function through activation of signal transduction pathways. These studies were the first to suggest that receptors may exist for bile acids. Ultimately, seminal studies by many investigators led to the discovery of several bile acid-activated receptors including the farnesoid X receptor, the vitamin D receptor, the pregnane X receptor, TGR5, α5 β1 integrin, and sphingosine-1-phosphate receptor 2. Several of these receptors are expressed outside of the gastrointestinal system, indicating that bile acids may have diverse functions throughout the body. Characterization of the functions of these receptors over the last two decades has identified many important roles for these receptors in regulation of bile acid synthesis, transport, and detoxification; regulation of glucose utilization; regulation of fatty acid synthesis and oxidation; regulation of immune cell function; regulation of energy expenditure; and regulation of neural processes such as gastric motility. Through these many functions, bile acids regulate many aspects of digestion ranging from uptake of essential vitamins to proper utilization of nutrients. Accordingly, within a short time period, bile acids moved beyond simple detergents and into the realm of complex signaling molecules. Because of the important processes that bile acids regulate through activation of receptors, drugs that target these receptors are under development for the treatment of several diseases, including cholestatic liver disease and metabolic syndrome. In this review, we will describe the various bile acid receptors, the signal transduction pathways activated by these receptors, and briefly discuss the physiological processes that

  14. Controllably local gene delivery mediated by polyelectrolyte multilayer films assembled from gene-loaded nanopolymersomes and hyaluronic acid

    Teng W

    2014-10-01

    a complex form. In vitro cell experiments demonstrate that PEM films can enhance the adhesion and proliferation of MSCs and efficiently transfect MSCs in situ in vitro for at least 4 days. Our results suggest that a (pNPs/HAn system can mediate efficient transfection in stem cells in a spatially and temporally controllable pattern, highlighting its huge potential in local gene therapy. Keywords: localized gene delivery, layer-by-layer self-assembly, gene-loaded nanopolymersomes, hyaluronic acid, polyelectrolyte multilayer films, mesenchymal stem cells

  15. Corrosion Inhibition of Mild Steel in Hydrochloric Acid Solution by Amino Acid Complexes

    K. Kiruthikajothi; G. Chandramohan

    2015-01-01

    Using the amino acids methionine and serine reduced Schiff base and their copper(II) complexes were synthesized. The inhibition effect of these copper (II) complexes on the corrosion of mild steel in 1 M HCl solution was investigated. The corrosion inhibition action is studied through weight loss method. Among the tested complexes [CuCl(SMet)PPh3.H2O] exhibited better corrosion inhibition at 3 mmol concentration. The adsorption of the complexes on the metal surface obeys Langmuir’s adsorption...

  16. Photoelectrochemical properties of WO3 nanoparticulate thin films prepared by carboxylic acid-assisted electrodeposition

    Optimisation of particle sizes of WO3 films is important for photoelectrochemical applications. However, most of the developed size-controlled synthesis techniques involve complicated instruments or vacuum systems. The present work presents an alternative method using carboxylic acid-assisted electrodeposition where WO3 thin films were deposited from peroxotungstic acid (PTA) solution containing different carboxylic acids (formic, oxalic, citric). The effects of carboxylic acids on the electrodeposition and the resultant morphological, mineralogical, optical, and photoelectrochemical properties of the WO3 films were investigated. The analysis showed that the films consisted of equiaxed nanoparticulate monoclinic WO3. The deposition thicknesses and the average grain (individual particle and agglomerate) sizes of the films were dependent on the amount of hydronium ions and the molecular weight and associated sizes of the conjugate bases released upon the dissociation of carboxylic acids in the PTA solutions, which result in hydrogen bond formation and molecular dispersion. The photocurrent densities of the films deposited with carboxylic acids were greater than that of the film deposited from pure PTA. These differences were attributed to improvements in (1) grain size, which controls photogenerated electron-hole transport, and (2) effective grain boundary area, which controls the numbers of active reaction sites and electron-hole recombination sites. - Highlights: • Carboxylic acid-assisted electrodeposition of WO3 films from peroxotungstic acid. • The types of carboxylic acids control the deposition rates and microstructure. • WO3 grain sizes and effective grain boundary areas determine the photocurrents. • Maximal photocurrent measured in the smallest-aggregate films (∼ 83 nm)

  17. Nucleic Acid-Peptide Complex Phase Controlled by DNA Hybridization

    Vieregg, Jeffrey; Lueckheide, Michael; Leon, Lorraine; Marciel, Amanda; Tirrell, Matthew

    When polyanions and polycations are mixed, counterion release drives formation of polymer-rich complexes that can either be solid (precipitates) or liquid (coacervates) depending on the properties of the polyelectrolytes. These complexes are important in many fields, from encapsulation of industrial polymers to membrane-free segregation of biomolecules such as nucleic acids and proteins. Condensation of long double-stranded DNA has been studied for several decades, but comparatively little attention has been paid to the polyelectrolyte behavior of oligonucleotides. We report here studies of DNA oligonucleotides (10 - 88 nt) complexed with polylysine (10 - 100 aa). Unexpectedly, we find that the phase of the resulting complexes is controlled by the hybridization state of the nucleic acid, with double-stranded DNA forming precipitates and single-stranded DNA forming coacervates. Stability increases with polyelectrolyte length and decreases with solution salt concentration, with complexes of the longer double-stranded polymers undergoing precipitate/coacervate/soluble transitions as ionic strength is increased. Mixing coacervates formed by complementary single-stranded oligonucleotides results in precipitate formation, raising the possibility of stimulus-responsive material design.

  18. Thermochemical properties of rare earth complexes with salicylic acid

    Fourteen rare earth complexes with salicylic acid RE(HSal)3.nH2O (HSal = C7H5O3; RE = La-Sm, n = 2; RE = Eu-Lu, n = 1) were synthesized and characterized by elemental analysis, and their thermal decomposition mechanism were studied with TG-DTG technology. The constant-volume combustion energies of complexes, ΔcU, were determined by a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, ΔcHm0, and standard molar enthalpies of formation, ΔfHmo, were calculated

  19. Processing and Characterization of Cellulose Nanocrystals/Polylactic Acid Nanocomposite Films

    Erin M. Sullivan

    2015-12-01

    Full Text Available The focus of this study is to examine the effect of cellulose nanocrystals (CNC on the properties of polylactic acid (PLA films. The films are fabricated via melt compounding and melt fiber spinning followed by compression molding. Film fracture morphology, thermal properties, crystallization behavior, thermo-mechanical behavior, and mechanical behavior were determined as a function of CNC content using scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, dynamic mechanical analysis, and tensile testing. Film crystallinity increases with increasing CNC content indicating CNC act as nucleating agents, promoting crystallization. Furthermore, the addition of CNC increased the film storage modulus and slightly broadened the glass transition region.

  20. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H3PO4/P2O5/Et3PO4 followed by acid–base reaction with Ca(OAc)2 to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for 1H, and 31P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO4 or CaCl2 were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min

  1. Metallic Langmuir and Langmuir-Blodgett films based on TTF derivatives and fatty acid

    Recent progress in the metallic conducting Langmuir-Blodgett (LB) films built from TTF derivative and fatty acids is reported. A simple LB method of transferring the mixed Langmuir (L) film of BEDO-TTF (BO) and stearic acid (SA) onto substrates provided metallic conducting LB films. A homogeneous L film formation on the water surface observed by Brewster angle microscope (BAM) is an essential factor for the well-ordered LB films. In the L film, the carboxylate group of fatty acid forms anion layer bringing about a spontaneous formation of mixed valence state (MVS) of BO layer. Similar spontaneous formation was also found in the molecular combination of nonoxygen-substituted donor of EDT-TTF and octadecanesulfonic acid (OS). This type of reaction would be useful for obtaining conducting LB films. For the LB films of BEDO-TTF and stearic acid, we found a negative transverse magnetoresistance at low temperature that was interpreted in the weak localization of a two-dimensional (2D) electronic system based on the well-defined conducting layer

  2. Ionic products of metal complexes with dithiocarbonic acid derivatives

    Ionic products of the complexes of certain sulfide-forming metal ions (In, Cd, Te, etc.) with alkyl derivates of dithiocarbonic acid have been defined. The possibility to use ionic products of alkyl xanthates for predicting the practicability of employing alkyl xanthates as analytic reagents in titrimetric methods of analysis, in extractional methods of separation and determination of elements, increase in the determination selectivity, is shown. 11 refs., 1 fig., 1 tab

  3. Technology of complex cleaning of mine acidic waters

    It is shown, that problem of complex use of mine waters includes two tasks: its cleaning and use of these waters in capacity of hydro-mineral raw. The floatation-extraction technology of mine acidic waters reprocessing is developed. The possibility of extraction processing of foam products of floatation with purpose of selective isolation of valuable components (Co, Ni, Sc, numerous of rare elements) is considered, optimum modes of metal extraction are defined. (author)

  4. Degradation and miscibility of poly(DL-lactic acid)/poly(glycolic acid) composite films: Effect of poly(DL-lactic-co-glycolic acid)

    Zhigang Ma; Na Zhao; Chengdong Xiong

    2012-08-01

    The in vitro degradation behaviour of poly(glycolic acid) (PGA) and its composite films containing poly(DL-lactic acid) (PDLLA) and poly(DL-lactic-co-glycolic acid) (PDLGA) were investigated via mass loss, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). All the films were prepared by solution casting, using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the solvent. Since the degradation rate of PDLLA is lower than that of PGA, those of the PDLLA/PGA composite films decreased. As a compatibilizer, PDLGA improved the compatibility and hydrolytic stability of PDLLA/PGA composite films. Changes in the composite films indicate that this kind of PGA-based composite biomaterial may be applicable to device design for clinical application in the future.

  5. Effect of inclusion complex on nitrous acid reaction with flavonoids

    Khalafi, Lida; Rafiee, Mohammad; Sedaghat, Sajjad

    2011-10-01

    The kinetic of the nitrous acid reactions with quercetin and catechin has been studied using spectrophotometric method in aqueous solution. The results show that these antioxidants participate in oxidation reactions with nitrous acid which is derived from protonation of nitrite ion in mild acidic conditions. Corresponding o-quinones as relatively stable products were detected by spectrophotometric techniques. pH dependence of the reactions has been examined and the rate constants of reactions were obtained by non-linear fitting of kinetic profiles. The effect of β-cyclodextrin on the oxidation pathway was another object of this study. It is shown that β-cyclodextrin has an inhibitory effect on the oxidation reaction. The rate constants of oxidation reactions for complexed forms and their stability constants were obtained based on changes in the reaction rates as a function of β-cyclodextrin concentration.

  6. Estimating the acidity of transition metal hydride and dihydrogen complexes by adding ligand acidity constants.

    Morris, Robert H

    2014-02-01

    A simple equation (pKa(THF) = ∑AL + Ccharge + Cnd + Cd6) can be used to obtain an estimate of the pKa of diamagnetic transition metal hydride and dihydrogen complexes in tetrahydrofuran, and, by use of conversion equations, in other solvents. It involves adding acidity constants AL for each of the ligands in the 5-, 6-, 7-, or 8-coordinate conjugate base complex of the hydride or dihydrogen complex along with a correction for the charge (Ccharge = -15, 0 or 30 for x = +1, 0 or -1 charge, respectively) and the periodic row of the transition metal (Cnd = 0 for 3d or 4d metal, 2 for 5d metal) as well as a correction for d(6) octahedral acids (Cd6 = 6 for d(6) metal ion in the acid, 0 for others) that are not dihydrogen complexes. Constants AL are provided for 13 commonly occurring ligand types; of these, nine neutral ligands are correlated with Lever's electrochemical ligand parameters EL. This method gives good estimates of the over 170 literature pKa values that range from less than zero to 50 with a standard deviation of 3 pKa units for complexes of the metals chromium to nickel, molybdenum, ruthenium to palladium, and tungsten to platinum in the periodic table. This approach allows a quick assessment of the acidity of hydride complexes found in nature (e.g., hydrogenases) and in industry (e.g., catalysis and hydrogen energy applications). The pKa values calculated for acids that have bulky or large bite angle chelating ligands deviate the most from this correlation. The method also provides an estimate of the base strength of the deprotonated form of the complex. PMID:24410025

  7. Quantification of Acidic Compounds in Complex Biomass-Derived Streams

    Karp, Eric M.; Nimlos, Claire T.; Deutch, Steve; Salvachua, Davinia; Cywar, Robin M.; Beckham, Gregg T.

    2016-09-07

    Biomass-derived streams that contain acidic compounds from the degradation of lignin and polysaccharides (e.g. black liquor, pyrolysis oil, pyrolytic lignin, etc.) are chemically complex solutions prone to instability and degradation during analysis, making quantification of compounds within them challenging. Here we present a robust analytical method to quantify acidic compounds in complex biomass-derived mixtures using ion exchange, sample reconstitution in pyridine and derivatization with BSTFA. The procedure is based on an earlier method originally reported for kraft black liquors and, in this work, is applied to identify and quantify a large slate of acidic compounds in corn stover derived alkaline pretreatment liquor (APL) as a function of pretreatment severity. Analysis of the samples is conducted with GCxGC-TOFMS to achieve good resolution of the components within the complex mixture. The results reveal the dominant low molecular weight components and their concentrations as a function of pretreatment severity. Application of this method is also demonstrated in the context of lignin conversion technologies by applying it to track the microbial conversion of an APL substrate. Here too excellent results are achieved, and the appearance and disappearance of compounds is observed in agreement with the known metabolic pathways of two bacteria, indicating the sample integrity was maintained throughout analysis. Finally, it is shown that this method applies more generally to lignin-rich materials by demonstrating its usefulness in analysis of pyrolysis oil and pyrolytic lignin.

  8. Chloroform extraction of ethyl xanthate complexes from sulphuric acid media

    The chloroform extraction of 30 elements (Fe, Co, Ni, Zn, Cd, Ge, Sn, V, As, Sb, Bi, Cu, Ag, Au, Mn, Re, Ga, In, Tl, Se, Te, Cr, Mo, U, Pt, Pd, Rh, Ir, Ru and Ce) from 0.1 to 8 M sulphuric acid in the presence of potassium ethyl xanthate has been studied. Pd(II), Bi, As(III), Sb(III), Se(IV) and Te(IV) are completely extracted and Au(III) is largely extracted over the range of acid concentration investigated. Fe(II), Tl(I), Rh(III) and Cr(VI) are only slightly extracted and Se(VI), Te(VI), Ru(III), Cr(III), Mn(II), Zn, Ce(IV), Ir(IV) and Ge(IV) are not extracted at all. Depending on the acid concentration, the remaining elements are all partly extracted. Results are compared with those obtained in an earlier study of the extraction of xanthate complexes from hydrochloric acid media. The processes involved in the formation of some xanthate complexes and potential analytical separations are discussed. (author)

  9. complex formation of americium (III) with humic acid

    The presence of humic substances in natural waters will modify the migration behavior of actinides in the geosphere due to the strong reaction properties of these ligands with actinides. Therefore, the possible reactions of humic acid with actinides have been studied widely in recent years. The complex formation of Am(III) with humic acid is studied with solvent extraction technique. The experiments are performed in the pH range from 4.0 to 8.0 in 0.1 mol/kg NaClO4 solution at ambient temperature. Experimental results show that the complex formation constants of Am(III) with humic acid are varied with the variation of pH value in solution. 1:2 complex is obtained in the experiments and the complex formation constants determined at each pH are: lgβ1 = 6.56 +- 0.05, lgβ2 = 10.77 +- 0.31 at pH 4.0. lgβ1 = 7.94 +- 0.11, lgβ2 = 11.80 +- 0.21 at pH = 5.0. lgβ1 = 10.74 +- 0.28, lgβ2 = 12.88 +- 0.49 at pH = 6.0. lgβ1 = 12.85 +- 0.30, lgβ2 = 14.80 +- 0.62 at pH = 7.0. lgβ1 = 14.88 +- 0.48, lgβ2 = 15.65 +- 0.69 at pH = 8.0, respectively. The dependence of the complex formation constant on pH is: lgβ1 = 2.16 (+-0.98)pH-2.34(+-0.93),lgβ2 1.28(+-1.04)pH+5.52(+-1.21), respectively

  10. Synthesis of thin film containing 4-amino-1,2,4-triazole iron(II) complexes

    Onggo, Djulia, E-mail: djulia@Chem.itb.ac.id [Inorganic and Physical Chemistry Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132 (Indonesia)

    2014-03-24

    The Iron(II) complex with 4-amino-1,2,4 triazole (NH{sub 2}-trz) ligand has potential applications as smart material since the compounds show a distinct color change from lilac at low temperature to colorless at high temperature. The lilac color of the complex represent the diamagnetic low spin state while the colorless correspond to the paramagnetic high spin state of iron(II). The transition between the two states could be tuned by changing the anionic group. Generally, the complex was synthesized directly from aqueous solution of iron(II) salt with considerable amounts of NH{sub 2}-trz solution produced solid powder compound. For application as an electronic molecular device, the complex should be obtained as a thin film. The transparent [Fe(NH{sub 2}trz){sub 3}]-Nafion film has been successfully obtained, however, no anion variation can be produced since the nafion is an anionic resin. In this work, the [Fe(NH{sub 2}trz){sub 3}]-complexes with several anions have been synthesized inside nata de coco membrane that commonly used as a medium for deposition metal nano-particles. After drying the membrane containing the complex became a thin film. At room temperature, the film containing iron(II) complexes of sulphate and nitrate salts show lilac color, similar to that of the original complexes in the powder form. On heating, the color of the complex film changed to colorless and this color change was observed reversibly. In contrast, the films containing perchlorate and tetrafluoroborate iron(II) complexes are colorless at room temperature and changed to lilac on cooling. The significant color changing of the iron(II)complexes in the nata de coco film can be used for demonstration thermo chromic effect of smart materials with relatively small amount of the compounds.

  11. Synthesis of thin film containing 4-amino-1,2,4-triazole iron(II) complexes

    The Iron(II) complex with 4-amino-1,2,4 triazole (NH2-trz) ligand has potential applications as smart material since the compounds show a distinct color change from lilac at low temperature to colorless at high temperature. The lilac color of the complex represent the diamagnetic low spin state while the colorless correspond to the paramagnetic high spin state of iron(II). The transition between the two states could be tuned by changing the anionic group. Generally, the complex was synthesized directly from aqueous solution of iron(II) salt with considerable amounts of NH2-trz solution produced solid powder compound. For application as an electronic molecular device, the complex should be obtained as a thin film. The transparent [Fe(NH2trz)3]-Nafion film has been successfully obtained, however, no anion variation can be produced since the nafion is an anionic resin. In this work, the [Fe(NH2trz)3]-complexes with several anions have been synthesized inside nata de coco membrane that commonly used as a medium for deposition metal nano-particles. After drying the membrane containing the complex became a thin film. At room temperature, the film containing iron(II) complexes of sulphate and nitrate salts show lilac color, similar to that of the original complexes in the powder form. On heating, the color of the complex film changed to colorless and this color change was observed reversibly. In contrast, the films containing perchlorate and tetrafluoroborate iron(II) complexes are colorless at room temperature and changed to lilac on cooling. The significant color changing of the iron(II)complexes in the nata de coco film can be used for demonstration thermo chromic effect of smart materials with relatively small amount of the compounds

  12. Tuning the properties of polyhydroxybutyrate films using acetic acid via solvent casting

    Anbukarasu, Preetam; Sauvageau, Dominic; Elias, Anastasia

    2015-12-01

    Biodegradable polyhydroxybutyrate (PHB) films were fabricated using acetic acid as an alternative to common solvents such as chloroform. The PHB films were prepared using a solvent casting process at temperatures ranging from 80 °C to 160 °C. The crystallinity, mechanical properties and surface morphology of the films cast at different temperatures were characterized and compared to PHB films cast using chloroform as a solvent. Results revealed that the properties of the PHB film varied considerably with solvent casting temperature. In general, samples processed with acetic acid at low temperatures had comparable mechanical properties to PHB cast using chloroform. This acetic acid based method is environmentally friendly, cost efficient and allows more flexible processing conditions and broader ranges of polymer properties than traditional methods.

  13. Ascorbic acid-containing whey protein film coatings for control of oxidation.

    Min, Seacheol; Krochta, John M

    2007-04-18

    A formulation for the whey protein isolate film or coating incorporating ascorbic acid (AA-WPI film or coating) was developed. Tensile and oxygen-barrier properties of the AA-WPI film were measured. Antioxidant effects of the AA-WPI coating on roasted peanuts were studied by comparing the values of peroxide (PO), thiobarbituric acid reactive substance (TBARS), and free-radical-scavenging activity, determined with noncoated peanuts and peanuts coated with WPI with and without ascorbic acid during storage at 21% relative humidity (RH) and 23, 35, and 50 degrees C. The incorporation of AA reduced elongation of WPI films. The oxygen-barrier property of the WPI film was significantly improved by incorporation of AA. The AA-WPI coating retarded lipid oxidation in peanuts significantly at 23, 35, and 50 degrees C. The AA-WPI coated peanuts were more red than noncoated peanuts at all storage temperatures. PMID:17367158

  14. Complex surfaces plated by thin-film deposition in one operation

    Buckley, D. H.; Przybyszewski, J. S.; Spalvins, T.

    1967-01-01

    Ion plating deposits thin film on complex surface in one operation. The ionized materials follow electric lines of force to all points on the objects, uniformly plating the surface from all sides simultaneously.

  15. Modification of hydrophobic polypeptide-based film by blending with hydrophilic poly(acrylic acid)

    Guoquan Zhu; Fagang Wang; Qiaochun Gao; Yuying Liu

    2013-01-01

    In this study, a series of poly(γ-benzyl L-glutamate)/poly(acrylic acid) (PBLG/PAA) polymer blend films were prepared by casting the polymer blend solution in dimethylsulfoxide (DMSO). The structure and morphology of the polymer blend film were investigated by Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). Thermal, mechanical, and chemical properties of PBLG/PAA polymer blend films were studied by Differential Scanning Calorimetry (DSC), Thermogra...

  16. Enhanced high temperature thermoelectric response of sulphuric acid treated conducting polymer thin films

    Kumar, Sarath

    2015-11-24

    We report the high temperature thermoelectric properties of solution processed pristine and sulphuric acid treated poly(3, 4-ethylenedioxythiophene):poly(4-styrenesulfonate) (or PEDOT:PSS) films. The acid treatment is shown to simultaneously enhance the electrical conductivity and Seebeck coefficient of the metal-like films, resulting in a five-fold increase in thermoelectric power factor (0.052 W/m. K ) at 460 K, compared to the pristine film. By using atomic force micrographs, Raman and impedance spectra and using a series heterogeneous model for electrical conductivity, we demonstrate that acid treatment results in the removal of PSS from the films, leading to the quenching of accumulated charge-induced energy barriers that prevent hopping conduction. The continuous removal of PSS with duration of acid treatment also alters the local band structure of PEDOT:PSS, resulting in simultaneous enhancement in Seebeck coefficient.

  17. Poly(lactic acid) and Osage Orange Wood Fiber Composites for Agricultural Mulch Films

    Osage orange wood(OO)was combined with poly(lactic acid)(PLA)to form a polymer composite intended for use as an agricultural mulch film. The PLA-OO mechanical properties were comparable to existing mulch film products and had the advantage of being completely biodegradable through a single growing ...

  18. Multilayer Film Fabrication and Photoelectric Conversion Property of Two Pyrrolidinofullerene Carboxylic Acid Derivatives

    2000-01-01

    Two multilayer films of pyrrolidinofullerene carboxylic acid derivatives, which exhibit photoelectric conversion property, are reported here. The first monolayers were fabricated on hydrophilic indium-tin-oxide (ITO), quartz, and mica by esterification reaction. The multilayers were characterized by contact angle and UV spectrum. The photoelectric conversion properties of both multilayer films were studied.

  19. Preparation of poly(lactic acid) and pectin composite films intended for application in antimicrobial packaging

    Composite films of pectin and poly(lactic acid) (PLA) were compounded by extrusion. A model antimicrobial polypeptide, nisin, was loaded into the film by diffusion. The incorporation of pectin into PLA resulted in a heterogeneous biphasic structure as revealed by scanning electronic microscopy, co...

  20. Chemical modification of chitosan film via surface grafting of citric acid molecular to promote the biomineralization

    Liu, Yang; Shen, Xin; Zhou, Huan; Wang, Yingjun; Deng, Linhong

    2016-05-01

    We develop a novel chitosan-citric acid film (abbreviated as CS-CA) suitable for biomedical applications in this study. In this CS-CA film, the citric acid, which is a harmless organic acid has been extensively investigated as a modifying agent on carbohydrate polymers, was cross-linked by 1-Ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) onto the surface of chitosan (CS) film. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirms the graft copolymerization of the modified chitosan film (CS-CA). Surface wettability, moisturizing performance, the capacity of mineralization in vitro and biocompatibility of the films were characterized. After modification, this CS-CA film has good hydrophilicity. It is very evident that the citric acid grafting treatment significantly promotes the biomineralization of the chitosan based substrates. Cell experiments show that the MC3T3-E1 osteoblasts can adhere and proliferate well on the surface of CS-CA film. This CS-CA film, which can be prepared in large quantities and at low cost, should have potential application in bone tissue engineering.

  1. Biodegradable films containing {alpha}-tocopherol/{beta}-cyclodextrin complex; Filmes biodegradaveis contendo {alpha}-tocoferol complexado em {beta}-ciclodextrina

    Motta, Caroline; Martelli, Silvia M.; Soldi, Valdir, E-mail: vsoldi@qmc.ufsc.br [Lab. de Materiais Polimericos (POLIMAT), Dept. de Quimica, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil); Barreto, Pedro L.M. [Lab. de Reologia (REOLAB), Dept. de Ciencia e Tecnologia de Alimentos, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil)

    2011-07-01

    The growing environmental concern about pollution and the need to reduce dependence of plastic industry in relation to non-renewable resources has increased the interest of both researchers and industry in the use of biopolymers. In this work {beta}-cyclodextrin/{alpha}-tocopherol complexes were prepared and characterized. In order to obtain polymeric active biofilms, the {beta}-cyclodextrin/{alpha}-tocopherol complex was incorporated into a polymeric matrix of carboxymethylcellulose. The {beta}-cyclodextrin/{alpha}-tocopherol complex was characterized through of X-ray diffraction and thermogravimetric analysis. The physicochemical properties of the films incorporated with the complex were evaluated through mechanical and colorimetric analysis and moisture sorption isotherm. (author)

  2. Preparation and acetone sensitive characteristics of nano-LaFeO3 semiconductor thin films by polymerization complex method

    Perovskite structure nano-LaFeO3 thin films were prepared by polymerization complex method using La(NO3)3.6H2O, FeCl3.6H2O as raw materials, citric acid (CA) as chelating agent and ethylene glycol (EG) as cross-linking agent. Nano-LaFeO3 thin films were fabricated on Al2O3 substrates by dip-coating, drying, pre-heating and sintering. The precursor and thin films were characterized by IR, AFM, XRD and SEM. The results revealed that the homogeneous LaFeO3 thin films with the grain size of about 37 nm and the thickness of approximately 2 μm were successfully synthesized at the sintering temperature of 650 deg. C. The nano-LaFeO3 semiconductor thin films have higher sensitive to acetone gas with lower concentration, which exposed to 80 ppm acetone gas show that sensitivity are 204, and response time are within 15 s at the testing temperature of 400 deg. C

  3. Electrophoretic deposition of composite halloysite nanotube–hydroxyapatite–hyaluronic acid films

    Highlights: ► Composite halloysite nanotubes–hydroxyapatite–hyaluronic acid films were prepared. ► Electrophoretic deposition method was used for deposition. ► Natural hyaluronic acid was used as a dispersing, charging and film forming agent. ► Film composition and deposition yield can be varied. ► The films can be used for biomedical implants with controlled release of drugs. -- Abstract: Electrophoretic deposition method has been developed for the deposition of biocomposite films containing halloysite nanotubes (HNTs), hydroxyapatite (HA) and hyaluronic acid. The method is based on the use of natural hyaluronate biopolymer as a dispersing and charging agent for HNT and HA and film forming agent for the fabrication of the composite films. The deposition kinetics was studied by the quartz crystal microbalance method. The composite films were studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis and electron microscopy. The composite films are promising materials for the fabrication of biomedical implants with advanced functional properties

  4. Electrophoretic deposition of composite halloysite nanotube–hydroxyapatite–hyaluronic acid films

    Deen, I. [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Zhitomirsky, I., E-mail: zhitom@mcmaster.ca [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada)

    2014-02-15

    Highlights: ► Composite halloysite nanotubes–hydroxyapatite–hyaluronic acid films were prepared. ► Electrophoretic deposition method was used for deposition. ► Natural hyaluronic acid was used as a dispersing, charging and film forming agent. ► Film composition and deposition yield can be varied. ► The films can be used for biomedical implants with controlled release of drugs. -- Abstract: Electrophoretic deposition method has been developed for the deposition of biocomposite films containing halloysite nanotubes (HNTs), hydroxyapatite (HA) and hyaluronic acid. The method is based on the use of natural hyaluronate biopolymer as a dispersing and charging agent for HNT and HA and film forming agent for the fabrication of the composite films. The deposition kinetics was studied by the quartz crystal microbalance method. The composite films were studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis and electron microscopy. The composite films are promising materials for the fabrication of biomedical implants with advanced functional properties.

  5. An iron(II) diketonate–diamine complex as precursor for thin film fabrication by atomic layer deposition

    Bratvold, Jon E., E-mail: j.e.bratvold@kjemi.uio.no [Centre for Materials Science and Nanotechnology (SMN)/Department of Chemistry, University of Oslo, PO Box 1033, Blindern, N-0315 Oslo (Norway); Carraro, Giorgio [Department of Chemistry, University of Padova and INSTM, via F. Marzolo 1, I-35131 Padova (Italy); Barreca, Davide [CNR-IENI and INSTM, Department of Chemistry, University of Padova, via F. Marzolo 1, I-35131 Padova (Italy); Nilsen, Ola [Centre for Materials Science and Nanotechnology (SMN)/Department of Chemistry, University of Oslo, PO Box 1033, Blindern, N-0315 Oslo (Norway)

    2015-08-30

    Highlights: • First report of Fe(hfa){sub 2}TMEDA as precursor in ALD and MLD. • Hybrid organic–inorganic films with oxalic acid as co-reactant between 125 and 350 °C. • Surface saturation evidenced by quartz crystal microbalance (QCM) analysis. • XPS confirms complete preservation of Fe(II) from precursor to film. • Deposition of α-Fe{sub 2}O{sub 3} when using ozone as co-reactant. - Abstract: A new divalent Fe precursor has been explored for deposition of iron-containing thin films by atomic layer deposition and molecular layer deposition (ALD/MLD). The Fe(II) β-diketonate-diamine complex, Fe(hfa){sub 2}TMEDA, (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate, TMEDA = N,N,N′,N′-tetramethylethylenediamine) can be handled in air, and sublimation at 60 °C ensures a satisfactory vaporization rate. The reactivity of the precursor does not allow for direct reaction with water as co-reactant. Nevertheless, it reacts with carboxylic acids, resulting in organic–inorganic hybrid materials, and with ozone, yielding α-Fe{sub 2}O{sub 3}. The divalent oxidation state of iron was maintained during deposition when oxalic acid was used as co-reactant, demonstrating the first preservation of Fe(II) from precursor to film during an MLD process. A self-saturating growth mode was proven by in situ quartz crystal microbalance (QCM) measurements, and the films were further characterized by grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS)

  6. An iron(II) diketonate–diamine complex as precursor for thin film fabrication by atomic layer deposition

    Highlights: • First report of Fe(hfa)2TMEDA as precursor in ALD and MLD. • Hybrid organic–inorganic films with oxalic acid as co-reactant between 125 and 350 °C. • Surface saturation evidenced by quartz crystal microbalance (QCM) analysis. • XPS confirms complete preservation of Fe(II) from precursor to film. • Deposition of α-Fe2O3 when using ozone as co-reactant. - Abstract: A new divalent Fe precursor has been explored for deposition of iron-containing thin films by atomic layer deposition and molecular layer deposition (ALD/MLD). The Fe(II) β-diketonate-diamine complex, Fe(hfa)2TMEDA, (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate, TMEDA = N,N,N′,N′-tetramethylethylenediamine) can be handled in air, and sublimation at 60 °C ensures a satisfactory vaporization rate. The reactivity of the precursor does not allow for direct reaction with water as co-reactant. Nevertheless, it reacts with carboxylic acids, resulting in organic–inorganic hybrid materials, and with ozone, yielding α-Fe2O3. The divalent oxidation state of iron was maintained during deposition when oxalic acid was used as co-reactant, demonstrating the first preservation of Fe(II) from precursor to film during an MLD process. A self-saturating growth mode was proven by in situ quartz crystal microbalance (QCM) measurements, and the films were further characterized by grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS)

  7. Self-assembled monolayer and multilayer formation using redox-active Ru complex with phosphonic acids on silicon oxide surface

    The formation of self-assembled monolayer and multilayer using redox-active Ru complex molecules with phosphonic acids on SiO2 surface has been examined using X-ray photoelectron spectroscopy (XPS), ellipsometry, and time of flight secondary mass-ion spectroscopy (TOF-SIMS). We found that an introduction of a Zr adlayer leads to higher surface molecular density of Ru complex SAMs on the SiO2 surface, compared to that of obtained from the direct adsorption of Ru complex monolayer on the SiO2 surface. We further tried to fabricate a multilayer film using this molecule with Zr(IV) ion acting as a chemical glue by a successive immersion process. The XPS data revealed that the molecular densities of the multilayers were also higher for the immobilization with Zr adlayer between Ru complex and SiO2 surface than those without the Zr adlayer, suggesting that Zr adlayer is effective in forming highly packed molecular layer of phosphonic acids on SiO2 surface. We found the film growth reached a saturation point after 6 layers on the SiO2 surface. The film growth saturation can be explained by a molecular domain boundary effect encountered due to the large tilt angle of the molecular layer.

  8. Sol-gel silica films embedding NIR- emitting Yb-quinolinolate complexes

    Sol-gel silica thin films embedding an ytterbium quinolinolato complex (YbClQ4) have been obtained using different alkoxides. Homogeneous, crack- and defect-free thin films of optical quality have been successfully deposited on glass substrate by dip-coating. The silica thin films have been characterized by time-resolved photoluminescence. The luminescence properties of the YbClQ4 are preserved in silica films prepared through an optimized sol-gel approach. The excited state lifetime of the lanthanide is comparable to those observed in bulk and longer than the corresponding ones in solution

  9. Characterization and Tribological Behavior of Octadecene, Dodecene and Undecenoic Acid Films on Si Substrate

    Jinfang ZHOU; Shengrong YANG

    2005-01-01

    The films of octadecene, dodecene, and undecenoic acid were prepared on H-terminated Si surface in the presence of ultraviolet irradiation. The resulted films were characterized with water-contact angle measurement and infrared spectroscopy. The friction-reducing behavior of the prepared films was examined on a static-dynamic friction coefficient measurement apparatus and on an atomic force microscope. It was found that all the reacted films on the Si substrate showed good friction-reducing ability; especially, the film of the octadecene exhibited the best frictionreducing ability. This was attributed to the transfer of the reacted films onto the counter face with formation of a transfer film on the counterpart surface, which led to the transformation of the sliding between the reacted films and the hard ceramic to that between the reacted films and its transfer film on the counterpart surface. The macroscopic and microscopic friction behaviors of the prepared films were dependent on their molecular chain lengths. Thus the octadecene reacted film with the highest degree of ordering arrangement showed the best friction-reducing and antiwear abilities in sliding against Si3 N4.

  10. Preparation and Properties of Moisture-absorbing Film Impregnated with Polyacrylic Acid Partial Sodium Salt Material

    Lee, Youn Suk; Park, Insik [Yonsei University, Wonju (Korea, Republic of); Choi, Hong Yeol [CJ Cheiljedang, Seoul (Korea, Republic of)

    2014-08-15

    Moisture is a major factor causing the deteriorative physical change, microbial growth, and chemical reaction of the products. In this study, the moisture absorbing composite films have been prepared with moisture absorbing material of polyacrylic acid partial sodium salt (PAPSS) impregnated on LLDPE polymer for the functional packaging applications. The results showed that PAPSS impregnated film illustrated uniformly dispersed PAPSS particles in the LLDPE polymer matrix. The transparency of the PAPSS impregnated film decreased slightly at higher PAPSS concentrations. An increase in the PAPSS content for moisture-absorbing films showed a similar decrease in tensile strength, percent elongation at break, and tear strength. Their values of films impregnated with PAPSS of 0.5, 1, and 2% showed no significant difference. Meanwhile, 4% PAPSS films significantly decreased the values of mechanical properties compared to the films impregnated with different PAPSS levels. Values of the oxygen permeability and water vapor permeability for PAPSS impregnated films decreased significantly with greater PAPSS. The results indicate that 4% PAPSS impregnated in LLDPE films had high affinity of moisture absorbencies compared to the other films. The mathematical equation that best described the moisture sorption isotherm of each film sample was the GAB equation at 25 .deg. C. The crystallization and melting temperatures of PAPSS films were influenced by the addition of PAPSS material, but showed good thermal stability.

  11. Complexes of carborane acids linked by strong hydrogen bonds: acidity scales.

    Grabowski, Sławomir J

    2016-06-28

    Carborane acids, currently known as the strongest acis, are analyzed and compared with other species classified as superacids as well as with selected mineral acids and carbocations. Calculations (B3LYP/6-311++G(d,p) level) on these moieties as well as on their conjugate bases were performed to evaluate corresponding proton affinities. In addition, the complexes of these species with the CHB11F11(-) anion and the complexes of the conjugate bases with the trimethylammonium cation were analyzed. The scales, based on spectroscopic results, DFT energies and on the topological QTAIM (Quantum Theory of Atoms in Molecules) parameters, are introduced and discussed to order the acidity of the species analyzed here. The properties of the bond critical points corresponding to the intermolecular contacts are discussed. The majority of the results show that HCHB11F11 carborane acid is the strongest in agreement with the previous experimental studies of Reed and coworkers. Very often the abovementioned acidity scales show that carborane acids are able to protonate hydrocarbons. PMID:27253195

  12. Enhancement of the wet properties of transparent chitosan-acetic-acid-salt films using microfibrillated cellulose.

    Nordqvist, David; Idermark, Johan; Hedenqvist, Mikael S; Gällstedt, Mikael; Ankerfors, Mikael; Lindström, Tom

    2007-08-01

    This report presents a new route to enhance the wet properties of chitosan-acetic-acid-salt films using microfibrillated cellulose (MFC). The enhancement makes it easier to form chitosan-acetic-acid-salt films into various shapes at room temperature in the wet state. Chitosan with MFC was compared with the well-known buffer treatment. It was observed that films containing 5 wt % MFC were visually identical to the buffered/unbuffered films without MFC. Field-emission scanning electron microscopy indicated that MFC formed a network with uniformly distributed fibrils and fibril bundles in the chitosan matrix. The addition of MFC reduced the risk of creases and deformation in the wet state because of a greater wet stiffness. The wet films containing MFC were also extensible. Although the stiffness, strength and extensibility were highest for the buffered films, the wet strength of the MFC-containing unbuffered films was sufficient for wet forming operations. The effects of MFC on the mechanical properties of the dry chitosan films were small or absent. It was concluded that the addition of MFC is an acceptable alternative to buffering for shaping chitosan films/products in the wet state. The advantages are that the "extra" processing step associated with buffering is unnecessary and that the film matrix remains more water-soluble. PMID:17645308

  13. Radiation-induced grafting of acrylic acid onto polypropylene film and its biodegradability

    Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Chaudhari, C. V.; Dubey, K. A.; Varshney, L.

    2016-06-01

    Polypropylene based commodity polyolefins are widely used in packaging, manufacturing, electrical, pharmaceutical and other applications. The aim of the present work is to study the effect of grafting of acrylic acid on the biodegradability of acrylic acid grafted polypropylene. The effect of different conditions showed that grafting percentage increased with increase in monomer concentration, radiation dose and inhibitor concentration but decreased with increase in radiation dose rate. The maximum grafting of 159.4% could be achieved at optimum conditions. The structure of grafted polypropylene films at different degree of grafting was characterized by EDS, FTIR, TGA, DSC, SEM and XRD. EDS studies showed that the increase in acrylic acid grafting percentage increased the hydrophilicity of the grafted films. FTIR studies indicated the presence of acrylic acid on the surface of polypropylene film. TGA studies revealed that thermal stability decreased with increase in grafting percentage. DSC studies showed that melting temperature and crystallinity of the grafted polypropylene films lower than polypropylene film. SEM studies indicated that increase in acrylic acid grafting percentage increased the wrinkles in the grafted films. The maximum biodegradability could be achieved to 6.85% for 90.5% grafting. This suggested that microorganisms present in the compost could biodegrade acrylic acid grafted polypropylene.

  14. Enhanced surface coverage and conductivity of Cu complex ink-coated films by laser sintering

    We here show that highly conductive copper films are obtainable from Cu complex ink by laser sintering. The synthesized Cu formate ink was spin-coated onto polyimide substrate and the coated films were scanned by an ultraviolet laser beam at 355 nm. During the sintering process, N2 gas was blown into the irradiated area to prevent oxidation. Unlike the typical thermal process, laser sintering resulted in tightly packed, dense structures. This made it possible to produce highly conducting thin films with uniform thickness. A minimum resistivity of 1.92 × 10−5 Ω cm was obtained. - Highlights: • Highly conductive Cu films are obtainable by sintering Cu complex ink with laser. • Laser-sintered films exhibit very uniform and dense microstructure. • A minimum resistivity of 1.92 × 10−5 Ω cm is achieved

  15. Complex formation of americium (III) with humic acid

    The presence of humic substances in natural waters will modify the migration behavior of actinides in the geosphere due to the strong reaction properties of these ligands with actinides. Therefore, the possible reactions of humic acid with actinides have been studied widely in recent years. The complex formation of Am (III) with humic acid is studied with solvent extraction technique in this paper. The experiments are performed in the pH range from 4.0 to 8.0 in 0.1 M NaClO4 solution at ambient temperature. Experimental results show that the complex formation constants of Am (III) with humic acid are varied with the variation of pH value in solution. 1:2 complex is obtained in the experiments and the complex formation constants determined at each pH are: lgβ1=6.56±0.05, lgβ2=10.77±0.31 at pH=4.0; lgβ1=7.94±0.11, lgβ2=11.80±0.21 at pH=5.0; lgβ1=10.74±0.28, lgβ2=12.88±0.49 at pH=6.0; lgβ1=12.85±0.30, lgβ2=14.80±0.62 at pH=7.0; lgβ1=14.88±0.48, lgβ2=15.65±0.69 at pH=8.0, respectively. The dependence of the complex of the complex formation constant on pH is: lgβ1=2.16(±0.98)pH-2.34(±1.03), lgβ2=1.28(±1.04)pH+5.52(±1.21), respectively. (author)

  16. From ligand to complexes: inhibition of HIV-1 Integrase by beta-diketo acid metal complexes

    Sechi, Mario; BACCHI, Alessia; Carcelli, Mauro; Fisicaro, Emilia; Rogolino, Dominga; Gates, Paul; Derudas, Marco; Al-Mawsawi, Laith Q.; Neamati, Nouri

    2006-01-01

    Recently, a class of compounds bearing a β-diketo acid moiety have emerged as the most promising lead in anti-HIV-1 IN drug discovery. It is believed that the β-diketo acid pharmacophoric motif could be involved in a functional sequestration of one or both divalent metal ions, which are critical cofactors at the enzyme catalytic site. This would subsequently block the transition state of the IN-DNA complex. In this scenario, it is of paramount importance to acquire information ...

  17. Spectrophotometric study of lanthanoid complexes with antipyrine and salicylic acid

    The extraction-spectrophotometric method has been used to study lanthanoid ion complexing (Pr, Nd, Ho and Er) with antipyrine (Ant) and salicylic acid (Sal). The component relationship in different-ligand compounds Ln:Aut:Sal=2:3:6 and solvate number equal to 5 are determined; molar extinction coefficients of binary and different-ligand compounds are calculated. Oscillator strengths of absorption bands corresponding to supersensitive transitions of neodymium, holmium, erbium and some most intensive praseodymium bands are calculated. The study of IR spectra of investigated compounds allows to conclude on formation of coordination bonds of the central atom with the antipyrine molecule through the oxygen of the carbonyl group as well as on carboxyl group hydrogen substitution for metal and formation of coordination bond with OH group in salicylic acid molecules

  18. Chemical vapour deposition of amorphous Ru(P) thin films from Ru trialkylphosphite hydride complexes.

    McCarty, W Jeffrey; Yang, Xiaoping; DePue Anderson, Lauren J; Jones, Richard A

    2012-11-21

    The ruthenium phosphite hydride complexes H(2)Ru(P(OR)(3))(4) (R = Me (1), Et (2), (i)Pr (3)) were used as CVD precursors for the deposition of films of amorphous ruthenium-phosphorus alloys. The as-deposited films were X-ray amorphous and XPS analysis revealed that they were predominantly comprised of Ru and P in zero oxidation states. XPS analysis also showed the presence of small amounts of oxidized ruthenium and phosphorus. The composition of the films was found to depend on ligand chemistry as well as the deposition conditions. The use of H(2) as the carrier gas had the effect of increasing the relative concentrations of P and O for all films. Annealing films to 700 °C under vacuum produced films of polycrystalline hcp Ru while a flowing stream of H(2) resulted in polycrystalline hcp RuP. PMID:23018487

  19. Antibacterial poly(lactic acid) (PLA) films grafting electrospun PLA/Ally isothioscyanate (AITC) fibers for food packaging

    Poly(lactic acid) (PLA) fibers of submicron sizes encapsulating allyl isothiocyanate (AITC) (PfA) were made and electrospun onto the surfaces of PLA films (PfA-g-film). SEM examination confirmed that the fibers were grafted to the PLA film after the (PfA-g-film) underwent air blowing and water washi...

  20. Electrochemical behaviour of niobium and niobium passive films in nitric acid solutions

    Electrochemical behaviour of bare niobium and phosphoric acid anodized niobium electrodes is investigated in nitric acid solutions. Electrochemical impedance spectroscopy and polarisation techniques have been used to investigate the open-circuit growth of the passive film. The stability of the anodic oxide film has been studied as a function of the formation voltage, formation current density and concentration of the ambient electrolyte. The results show that the Nb-Nb2O5-1M HNO3 does not behave as a perfect dielectric. The flat band potential and donor concentration of the semiconducting anodic oxide film have been calculated from the Mott-Schottky plots. (author)

  1. Highly ordered thin films prepared with octabutoxy copper phthalocyanine complexes

    Langmuir-Blodgett (LB) films of copper (II) 1,4,8,11,15,18,22,25-octabutoxyphthalocyanine, nCuPc(OBu)8, (non-peripheral substitution) and copper (II) 2,3,9,10,16,17,23,24-octabutoxyphthalocyanine, pCuPc(OBu)8, (peripheral substitution), were fabricated and characterized by optical spectroscopy and scanning probe microscopy. The LB films were transferred onto hydrophilic substrates by vertical dipping. Although they posses relatively short polar substituents both compounds form smooth, uniform, dense, and highly stable LB monolayers composed of linear arrays of cofacial oligomers. The long range discotic assemblies of LB and spun cast films of pCuPc(OBu)8 and nCuPc(OBu)8 posses physical and chemical properties favorable for molecular electronic device application

  2. Highly ordered thin films prepared with octabutoxy copper phthalocyanine complexes.

    Stevenson, Kelly; Miyashita, Naoko; Smieja, Joanne; Mazur, Ursula

    2003-01-01

    Langmuir-Blodgett (LB) films of copper (II) 1,4,8,11,15,18,22,25-octabutoxyphthalocyanine, nCuPc(OBu)(8), (non-peripheral substitution) and copper (II) 2,3,9,10,16,17,23,24-octabutoxyphthalocyanine, pCuPc(OBu)(8), (peripheral substitution), were fabricated and characterized by optical spectroscopy and scanning probe microscopy. The LB films were transferred onto hydrophilic substrates by vertical dipping. Although they posses relatively short polar substituents both compounds form smooth, uniform, dense, and highly stable LB monolayers composed of linear arrays of cofacial oligomers. The long range discotic assemblies of LB and spun cast films of pCuPc(OBu)(8) and nCuPc(OBu)(8) posses physical and chemical properties favorable for molecular electronic device application. PMID:12801680

  3. Highly ordered thin films prepared with octabutoxy copper phthalocyanine complexes

    Stevenson, Kelly; Miyashita, Naoko; Smieja, Joanne; Mazur, Ursula

    2003-10-15

    Langmuir-Blodgett (LB) films of copper (II) 1,4,8,11,15,18,22,25-octabutoxyphthalocyanine, nCuPc(OBu){sub 8}, (non-peripheral substitution) and copper (II) 2,3,9,10,16,17,23,24-octabutoxyphthalocyanine, pCuPc(OBu){sub 8}, (peripheral substitution), were fabricated and characterized by optical spectroscopy and scanning probe microscopy. The LB films were transferred onto hydrophilic substrates by vertical dipping. Although they posses relatively short polar substituents both compounds form smooth, uniform, dense, and highly stable LB monolayers composed of linear arrays of cofacial oligomers. The long range discotic assemblies of LB and spun cast films of pCuPc(OBu){sub 8} and nCuPc(OBu){sub 8} posses physical and chemical properties favorable for molecular electronic device application.

  4. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    Kim, Han-Sem; Song, Minsoo, E-mail: minsoosong00@gmail.com; Lee, Eun-Jung; Shin, Ueon Sang, E-mail: usshin12@dankook.ac.kr

    2015-06-01

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H{sub 3}PO{sub 4}/P{sub 2}O{sub 5}/Et{sub 3}PO{sub 4} followed by acid–base reaction with Ca(OAc){sub 2} to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for {sup 1}H, and {sup 31}P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO{sub 4} or CaCl{sub 2} were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min.

  5. Structure and function analysis of protein–nucleic acid complexes

    Kuznetsova, S. A.; Oretskaya, T. S.

    2016-05-01

    The review summarizes published data on the results and achievements in the field of structure and function analysis of protein–nucleic acid complexes by means of main physical and biochemical methods, including X-ray diffraction, nuclear magnetic resonance spectroscopy, electron and atomic force microscopy, small-angle X-ray and neutron scattering, footprinting and cross-linking. Special attention is given to combined approaches. The advantages and limitations of each method are considered, and the prospects of their application for wide-scale structural studies in vivo are discussed. The bibliography includes 145 references.

  6. Incorporation of europium III complex into nanoparticles and films obtained by the Sol-Gel methodology

    Faley Jean de Sousa

    2010-03-01

    Full Text Available The sol-gel process is very effective for the preparation of new materials with potential applications in optics, sensors, catalyst supports, coatings, and specialty inorganic polymers that can be used as hosts for the accommodation of organic molecules. The low temperature employed in the process is the main advantage of this methodology. In this work, the europium (III complex with 1,10-phenantroline was prepared, and this luminescent complex was incorporated into silica nanoparticles and films by the sol-gel process. The nanoparticles were obtained by the modified Stöber methodology. The films were obtained by the dip-coating technique, at different deposition rates and numbers of layers. The nanoparticles and films were characterized by photoluminescence, thermal analysis, and Raman and infrared spectroscopies. Characterization revealed that the europium (III complex was not affected upon incorporation into the nanoparticles and films, opening a new field for the application of these materials.

  7. A complex magnetic structure of ultrathin Fe films on Rh (001) surfaces

    Takada, Masaki [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Lana Gastelois, Pedro [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Servico de Nanotecnologia, Centro de Desenvolvimento da Tecnologia Nuclear, 31270-901 BeloHorizonte, MG (Brazil); Przybylski, Marek, E-mail: mprzybyl@mpi-halle.de [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Krakow (Poland); Kirschner, Juergen [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Naturwissenschaftliche Fakultaet II, Martin-Luther-Universitaet Halle-Wittenberg, 06120 Halle (Germany)

    2013-03-15

    We conducted a structural and magnetic analysis of ultrathin Fe films on Rh (001) surfaces by using low electron energy diffraction (LEED), magneto-optical Kerr effects (MOKE) and spin-polarized scanning tunneling microscopy (SP-STM). The films in the investigated thickness range up to 6 monolayers (ML) are pseudomorphic to the Rh (001) substrate. While Fe films thinner than 3 ML grow layer-by-layer at room temperature (RT), Fe films thicker than 4 ML form islands. 1 ML Fe films do not show any hysteresis loops even at low temperature. Polar hysteresis loops for the 2 ML and 3 ML thick films appear at low temperatures. When 1 ML thick Fe films were studied by Cr- and Fe-coated W tips, a (2 Multiplication-Sign 3) and stripe structures were observed, respectively. The structures originate from a complex magnetic structure of 1 ML Fe. Based on the SP-STM results we propose a spin configuration model of a 1 ML Fe film. - Highlights: Black-Right-Pointing-Pointer We studied structural and magnetic properties of Fe films grown on an Rh (001). Black-Right-Pointing-Pointer MOKE measurements revealed that Fe films thicker than 2 ML are ferromagnetic at 5 K. Black-Right-Pointing-Pointer Fe films with thickness of 2 ML and 3 ML exhibit out-of-plane magnetization, those thicker than 4 ML show in-plane magnetization. Black-Right-Pointing-Pointer 1 ML Fe films have a complex magnetic configuration with zero net magnetization. Black-Right-Pointing-Pointer A spin configuration model of 1 ML Fe is proposed based on an SP-STM observation.

  8. Modification of hydrophobic polypeptide-based film by blending with hydrophilic poly(acrylic acid

    Guoquan Zhu

    2013-01-01

    Full Text Available In this study, a series of poly(γ-benzyl L-glutamate/poly(acrylic acid (PBLG/PAA polymer blend films were prepared by casting the polymer blend solution in dimethylsulfoxide (DMSO. The structure and morphology of the polymer blend film were investigated by Fourier Transform Infrared Spectroscopy (FT-IR and Scanning Electron Microscopy (SEM. Thermal, mechanical, and chemical properties of PBLG/PAA polymer blend films were studied by Differential Scanning Calorimetry (DSC, Thermogravimetric (TG Analysis, Tensile Tests, and measurements of Surface Contact Angles. The results revealed that the introduction of PAA could exert great effects on the structure and properties of the polypeptide films.

  9. Dynamics of the layer-by-layer assembly of a poly(acrylic acid)-lanthanide complex colloid and poly(diallyldimethyl ammonium).

    Xu, Jiali; Wang, Zhiliang; Wen, Lingang; Zhou, Xianju; Xu, Jian; Yang, Shuguang

    2016-01-21

    Poly(acrylic acid) (PAA) and lanthanide (Ln) ions, such as Ce(3+), Eu(3+), and Tb(3+), were prepared as dispersed complex colloidal particles through three different protocols with rigorous control of the pH value and mixing ratio. The negatively charged PAA-Ln complex particles were layer-by-layer (LbL) assembled with positively charged poly(diallyldimethyl ammonium) (PDDA) to prepare a thin film. The film thickness growth is much quicker than PDDA/PAA film. Due to the incorporation of Ln(3+) ions, the film exhibits fluorescence. During LbL assembly, PDDA-PAA association based on electrostatic force and PAA-Ce association based on coordination are in competition, which leads to the LbL assembly of PDDA and PAA-Ln complex colloidal particles being a complicated dynamic process. PMID:26549538

  10. Effect of acid and alkaline solubilization on the properties of surimi based film

    Thummanoon Prodpran

    2005-05-01

    Full Text Available The effect of acid and alkaline solubilizing processes on the properties of the protein based film from threadfin bream surimi was investigated. Surimi films prepared from both processes had the similar light transmission, tensile strength (TS and elongation at break (EAB (P<0.05. However, film with alkaline process had slightly lower water vapor permeability (WVP, compared to that prepared by acid solubilizing process. The protein concentration in the film-forming solution directly affected the properties of the film. Increase in protein concentration resulted in an increase in TS, EAB as well as WVP. The film prepared by acid solubilizing process had an increase in yellowish color as evidenced by the continuous increase in b* and E* values during the storage at r oom temperature. The acid and alkali solubilizing processes caused the degradation of muscle protein in surimi, especially with increasing exposure time. Therefore, solubilizing process had the influence on the properties of the protein film from threadfin bream surimi.

  11. A study on the performance of hyaluronic acid immobilized chitosan film

    Wang Yingjun; Guo Li; Ren Li; Yin Shiheng [Biomaterial Research Institute, College of Material Science and Engineering, South China University of Technology, Guangzhou, 510640 (China); Ge Jian; Gao Qianying [State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060 (China); Luxbacher, Thomas; Luo Shijing, E-mail: imwangyj@scut.edu.c, E-mail: psliren@scut.edu.c [Anton Paar GmbH, Anton-Paar-Strasse 20, A-8054 Graz (Austria)

    2009-06-15

    In order to improve hydrophilicity and biocompatibility of chitosan, hyaluronic acid was immobilized onto the surface of chitosan film. The structure of films was characterized by Fourier transformed infrared spectroscopy with attenuated total reflectance (ATR-FTIR), x-ray photoelectron spectroscopy (XPS) and zeta potential. Results confirmed that hyaluronic acid was successfully immobilized on chitosan film. Transparency, water absorption percentage and contact angle of films were characterized. Results showed that there was no significant variation in transparency (p < 0.05) before and after immobilization, the maximum was up to 99% which was enough for corneal regeneration in clinical applications. After the immobilization, the time-dependent contact angle declined sharply (from 91.8 deg. to 67.7 deg. at 100 s). The hydrophilicity was significantly improved. The methylthiazol tetrazolium (MTT) (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay was used to assess cell viability and proliferation. Results showed that human cornea epithelial cells (HCEC) grew better on hyaluronic acid immobilized chitosan films than on chitosan films. The hyaluronic acid immobilized chitosan film could be a promising candidate material for corneal regeneration.

  12. A study on the performance of hyaluronic acid immobilized chitosan film

    In order to improve hydrophilicity and biocompatibility of chitosan, hyaluronic acid was immobilized onto the surface of chitosan film. The structure of films was characterized by Fourier transformed infrared spectroscopy with attenuated total reflectance (ATR-FTIR), x-ray photoelectron spectroscopy (XPS) and zeta potential. Results confirmed that hyaluronic acid was successfully immobilized on chitosan film. Transparency, water absorption percentage and contact angle of films were characterized. Results showed that there was no significant variation in transparency (p < 0.05) before and after immobilization, the maximum was up to 99% which was enough for corneal regeneration in clinical applications. After the immobilization, the time-dependent contact angle declined sharply (from 91.8 deg. to 67.7 deg. at 100 s). The hydrophilicity was significantly improved. The methylthiazol tetrazolium (MTT) (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay was used to assess cell viability and proliferation. Results showed that human cornea epithelial cells (HCEC) grew better on hyaluronic acid immobilized chitosan films than on chitosan films. The hyaluronic acid immobilized chitosan film could be a promising candidate material for corneal regeneration.

  13. Complexation behavior of Np(IV) and humic acid

    Complexation behavior between humic acid (HA), which is one of the natural organic matter in groundwater, and tetravalent neptunium (Np(IV)) was investigated by batch type complexation experiments and solvent extraction by TTA xylene, focused on the effect of concentration and molecular weight of HA. In addition, proton dissociation behavior from HA was evaluated by acid-base titration and its results was used for the calculation of stability constant of Np(IV) and HA complex. The results of titration of HA was analysed based on NICA-Donnan model and parameters used for evaluation of proton dissociation behavior were calculated. The charge density of HA in pH 8, which is necessary for calculation of stability constant, was evaluated as -4.35 meq/g. The complexation experiments were carried out under the conditions as follows; 1x10-5 mol/l of initial Np concentration, from 5 to 500 mg/l of HA concentration, pH 8, in the 0.1 mol/l NaClO4, and 0.05 mol/l Na2S2O4 as reductant to keep Np as tetravalent. As a result, in the presence of 5 mg/l of HA, total concentration of Np was increased at least one order of magnitude higher than in the case without HA. All added Np existed as soluble species in the presence of more than 50 mg/l of HA. Np in the solution was fractionated by solvent extraction using TTA-xylene as follows; 1) extractable Np into the organic phase, 2) non-extractable Np remained in the inorganic phase, and 3) precipitated Np. These were considered as 1) free Np(VI) or weakly binded Np(IV) and 3) strongly binded Np(IV), while 2) Np(IV)-fulvic acid complex could be suggested. Consequently, stability constant, log βα=26.31, was obtained. In addition, compared with Am(III) or Np(V), accessible site in the HA for Np(IV) seems to be quite limited. (author)

  14. Characterization of titanium thin films anodically grown in phosphoric acid; Caracterisation des films d'oxyde de titane obtenus anodiquement dans l'acide phosphorique

    Khadiri, M.E.; Benyaich [Faculte des Sciences Semlalia, Lab. d' Electrochimie et Chimie Analytique, Marakech (Morocco); Oueriagli, A.; Outzourhit, A.; Ameziane, E.L. [Faculte des Sciences Semlalia, Lab. de Physique du Solide et des Couches Minces, Marakech (Morocco)

    2004-08-01

    Ti-Cu(2%) alloy was anodized in a 5 M phosphoric acid solution under various voltages ranging from 10 to 35 V. The composition, the structural and optical properties of the as-grown oxide films were studied. It was found that the color of the anodized substrates varied from yellow to blue depending on the anodizing voltage. The films formed on the alloy are amorphous and the oxidation state of Ti on their surface is mainly +4. On the other hand it was found that the thickness of the films increases linearly with anodization voltage at rate of 1.94 nm/V, while the refractive index at the wavelength corresponding to the reflectance minimum was practically constant. These films were also found to have excellent protective properties for the examined alloy. (authors)

  15. Crosslinked collagen-gelatin-hyaluronic acid biomimetic film for cornea tissue engineering applications

    Liu, Yang; Ren, Li, E-mail: psliren@scut.edu.cn; Wang, Yingjun, E-mail: imwangyj@163.com

    2013-01-01

    Cornea disease may lead to blindness and keratoplasty is considered as an effective treatment method. However, there is a severe shortage of donor corneas worldwide. This paper presents the crosslinked collagen (Col)-gelatin (Gel)-hyaluronic acid (HA) films developed by making use of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as the crosslinker. The test results on the physical and biological properties indicate that the CGH631 film (the mass ratio of Col:Gel:HA = 6:3:1) has appropriate optical performance, hydrophilicity and mechanical properties. The diffusion properties of the CGH631 film to NaCl and tryptophan are also satisfactory and the measured data are 2.43 Multiplication-Sign 10{sup -6} cm{sup 2}/s and 7.97 Multiplication-Sign 10{sup -7} cm{sup 2}/s, respectively. In addition, cell viability studies demonstrate that the CGH631 film has good biocompatibility, on which human corneal epithelial cells attached and proliferated well. This biocompatible film may have potential use in cornea tissue engineering. - Highlights: Black-Right-Pointing-Pointer Crosslinked collagen-gelatin-hyaluronic acid films were fabricated in this study. Black-Right-Pointing-Pointer The film had appropriate physical properties. Black-Right-Pointing-Pointer Diffusion coefficient of the film was comparable with the human cornea. Black-Right-Pointing-Pointer HCEC viability studies confirmed the biocompatibility of the film.

  16. Crosslinked collagen–gelatin–hyaluronic acid biomimetic film for cornea tissue engineering applications

    Cornea disease may lead to blindness and keratoplasty is considered as an effective treatment method. However, there is a severe shortage of donor corneas worldwide. This paper presents the crosslinked collagen (Col)–gelatin (Gel)–hyaluronic acid (HA) films developed by making use of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as the crosslinker. The test results on the physical and biological properties indicate that the CGH631 film (the mass ratio of Col:Gel:HA = 6:3:1) has appropriate optical performance, hydrophilicity and mechanical properties. The diffusion properties of the CGH631 film to NaCl and tryptophan are also satisfactory and the measured data are 2.43 × 10−6 cm2/s and 7.97 × 10−7 cm2/s, respectively. In addition, cell viability studies demonstrate that the CGH631 film has good biocompatibility, on which human corneal epithelial cells attached and proliferated well. This biocompatible film may have potential use in cornea tissue engineering. - Highlights: ► Crosslinked collagen–gelatin–hyaluronic acid films were fabricated in this study. ► The film had appropriate physical properties. ► Diffusion coefficient of the film was comparable with the human cornea. ► HCEC viability studies confirmed the biocompatibility of the film.

  17. Thermally driven stability of octadecylphosphonic acid thin films grown on SS316L.

    Lim, Min Soo; Smiley, Katelyn J; Gawalt, Ellen S

    2010-01-01

    Stainless steel 316L is widely used as a biomedical implant material; however, there is concern about the corrosion of metallic implants in the physiological environment. The corrosion process can cause mechanical failure due to resulting cracks and cavities in the implant. Alkyl phosphonic acid forms a thin film by self-assembly on the stainless steel surface and this report conclusively shows that thermal treatment of the octadecylphosphonic acid (ODPA) film greatly enhances the stability of the ODPA molecules on the substrate surface. AFM images taken from the modified substrates revealed that thermally treated films remain intact after methanol, THF, and water flushes, whereas untreated films suffer substantial loss. Water contact angles also show that the hydrophobicity of thermally treated films does not diminish after being incubated in a dynamic flow of water for a 3-hour period, whereas the untreated film becomes increasingly hydrophilic due to loss of ODPA. IR spectra taken of both treated and untreated films after water and THF flushes show that the remaining film retains its initial crystallinity. A model is suggested to explain the stability of ODPA film enhanced by thermal treatment. An ODPA molecule is physisorbed to the surface weakly by hydrogen bonding. Heating drives away water molecules leading to the formation of strong monodentate or mixed mono/bi-dentate bonds of ODPA molecule to the surface. PMID:20648546

  18. Aggregation properties of tetrachloroperylene-tetracarboxylic acid in binary Langmuir and Langmuir–Blodgett films

    The Langmuir and Langmuir–Blodgett films formed of tetra-n-butyl-1,6,7,12-tetrachloroperylene-3,4,9,10-tetracarboxylate and its binary mixtures with 4-octyl-4′-cyanobiphenyl and arachidic acid have been studied. The Langmuir films were characterized by surface pressure versus mean molecular area isotherms and the films morphology observations were made by means of a Brewster angle microscope. The miscibility of the compounds was determined. Subsequently, the Langmuir films were transferred onto hydrophilic quartz substrates forming the monolayer Langmuir–Blodgett films. The electronic absorption and fluorescence spectra reveal aggregation of the chromophores in ground state driven by π–π molecular orbitals interactions. Perylene-like dye aggregation depends upon the dye concentration in the dye/liquid crystal mixed films and is concentration-independent in dye/arachidic acid one. -- Highlights: • A new perylene derivative with four chlorine atoms in the core was synthetized. • Langmuir films of pure dye and its binary mixtures were studied thermodynamically. • The miscibility of the components in the films changes the π–π stacking of the dye. • We describe the dye aggregation in the pure and mixed films deposited onto quartz

  19. Aggregation properties of tetrachloroperylene-tetracarboxylic acid in binary Langmuir and Langmuir–Blodgett films

    Modlińska, Anna; Piosik, Emilia [Faculty of Technical Physics, Poznan University of Technology, Poznan (Poland); Paluszkiewicz, Joanna [Institute of Polymers and Dyes Technology, Lodz University of Technology, Lodz (Poland); Martyński, Tomasz, E-mail: tomasz.martynski@put.poznan.pl [Faculty of Technical Physics, Poznan University of Technology, Poznan (Poland)

    2014-04-15

    The Langmuir and Langmuir–Blodgett films formed of tetra-n-butyl-1,6,7,12-tetrachloroperylene-3,4,9,10-tetracarboxylate and its binary mixtures with 4-octyl-4′-cyanobiphenyl and arachidic acid have been studied. The Langmuir films were characterized by surface pressure versus mean molecular area isotherms and the films morphology observations were made by means of a Brewster angle microscope. The miscibility of the compounds was determined. Subsequently, the Langmuir films were transferred onto hydrophilic quartz substrates forming the monolayer Langmuir–Blodgett films. The electronic absorption and fluorescence spectra reveal aggregation of the chromophores in ground state driven by π–π molecular orbitals interactions. Perylene-like dye aggregation depends upon the dye concentration in the dye/liquid crystal mixed films and is concentration-independent in dye/arachidic acid one. -- Highlights: • A new perylene derivative with four chlorine atoms in the core was synthetized. • Langmuir films of pure dye and its binary mixtures were studied thermodynamically. • The miscibility of the components in the films changes the π–π stacking of the dye. • We describe the dye aggregation in the pure and mixed films deposited onto quartz.

  20. Influencing of resorption and side-effects of salicylic acid by complexing with β-cyclodextrin

    After oral administration of 14C-labelled salicylic acid and its β-cyclodextrin complex to rats, the radioactivity level of the blood reached its maximum during the first 2 h. The blood level obtained with the complex is somewhat but not significantly lower than with free acid. Since the resorption of cyclodextrin is a considerably slower process, it is very likely that the resorption of salicylic acid takes place in the form of free acid after dissociation of the complex. The urinary excretion cumulative curves showed that the free salicylic acid was completely excreted, while about 10% of the salicylic acid administered in the form of complex is lost. The cyclodextrin complex formation increased the pK values of all hydroxybenzoic acids. Direct observations revealed that complex formation decreased the stomach-irritating effect of salicylic acid. The ratio of radioactivity was nearly the same in the organs of animals treated by both free salicylic and cyclodextrin complex. (author)

  1. Effects of preirradiation graft polymerization of acrylic acid onto polyethylene film

    With the aid of preirradiation method of grafting onto low-density polyethylene film, a systematic investigation was made of grafting of aqueous acrylic acid under conditions such as monomer concentrations, irradiation dose, dose rate, reaction time, the effect of concentrations of Mohr's salt and sulphuric acid on the graft reaction. (author)

  2. Investigation of molecular interactions in the complex formation of tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid

    2008-01-01

    The molecular interactions in the complex formation of two tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid are investigated. The complex formation with a 1:1 stoichiometry between tartaric acid derivatives and D2EHPA can be obtained through UV-Vis titration, NMR chemical shifts and molecular dynamic simulations. Furthermore, the differences of the two complexes on the binding constants and strength of hydrogen bonds can also be determined. Such research will ideally provide insight into ways of regulating the complex forming properties of tartaric acid derivatives for composing or syn- thesizing new chiral resolving agents.

  3. Investigation of molecular interactions in the complex formation of tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid

    TAN Bin; ZHAI Zheng; LUO GuangSheng; WANG JiaDing

    2008-01-01

    The molecular interactions in the complex formation of two tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid are investigated. The complex formation with a 1:1 stoichiometry between tartaric acid derivatives and D2EHPA can be obtained through UV-Vis titration, NMR chemical shifts and molecular dynamic simulations. Furthermore, the differences of the two complexes on the binding constants and strength of hydrogen bonds can also be determined. Such research will ideally provide insight into ways of regulating the complex forming properties of tartaric acid derivatives for composing or syn-thesizing new chiral resolving agents.

  4. α-Lactalbumin:Oleic Acid Complex Spontaneously Delivers Oleic Acid to Artificial and Erythrocyte Membranes.

    Wen, Hanzhen; Strømland, Øyvind; Halskau, Øyvind

    2015-09-25

    Human α-lactalbumin made lethal to tumor cells (HAMLET) is a tumoricidal complex consisting of human α-lactalbumin and multiple oleic acids (OAs). OA has been shown to play a key role in the activity of HAMLET and its related complexes, generally known as protein-fatty acid (PFA) complexes. In contrast to what is known about the fate of the protein component of such complexes, information about what happens to OA during their action is still lacking. We monitored the membrane, OA and protein components of bovine α-lactalbumin complexed with OA (BLAOA; a HAMLET-like substance) and how they associate with each other. Using ultracentrifugation, we found that the OA and lipid components follow each other closely. We then firmly identify a transfer of OA from BLAOA to both artificial and erythrocyte membranes, indicating that natural cells respond similarly to BLAOA treatment as artificial membranes. Uncomplexed OA is unable to similarly affect membranes at the conditions tested, even at elevated concentrations. Thus, BLAOA can spontaneously transfer OA to a lipid membrane. After the interaction with the membrane, the protein is likely to have lost most or all of its OA. We suggest a mechanism for passive import of mainly uncomplexed protein into cells, using existing models for OA's effect on membranes. Our results are consistent with a membrane destabilization mediated predominantly by OA insertion being a significant contribution to PFA cytotoxicity. PMID:26297199

  5. Properties of CdS films prepared from thiourea complexes of cadmium salts

    One studied the effect of chemical nature of cadmium salt thiourea complex on the optical, electrical and structural properties of cadmium sulfide films. It was shown that the effect of chemical nature of thiourea complexes was associated with changing of the material chemical history. One may conclude that the composition and point symmetry of coordination compounds dictate, defect character and space symmetry of a new solid phase. Simulating the internal coordination sphere of the complex one may govern the properties of cadmium sulfide semiconducting films

  6. Dual Fatty Acid Elongase Complex Interactions in Arabidopsis.

    Morineau, Céline; Gissot, Lionel; Bellec, Yannick; Hematy, Kian; Tellier, Frédérique; Renne, Charlotte; Haslam, Richard; Beaudoin, Frédéric; Napier, Johnathan; Faure, Jean-Denis

    2016-01-01

    Very long chain fatty acids (VLCFAs) are involved in plant development and particularly in several cellular processes such as membrane trafficking, cell division and cell differentiation. However, the precise role of VLCFAs in these different cellular processes is still poorly understood in plants. In order to identify new factors associated with the biosynthesis or function of VLCFAs, a yeast multicopy suppressor screen was carried out in a yeast mutant strain defective for fatty acid elongation. Loss of function of the elongase 3 hydroxyacyl-CoA dehydratase PHS1 in yeast and PASTICCINO2 in plants prevents growth and induces cytokinesis defects. PROTEIN TYROSIN PHOSPHATASE-LIKE (PTPLA) previously characterized as an inactive dehydratase was able to restore yeast phs1 growth and VLCFAs elongation but not the plant pas2-1 defects. PTPLA interacted with elongase subunits in the Endoplasmic Reticulum (ER) and its absence induced the accumulation of 3-hydroxyacyl-CoA as expected from a dehydratase involved in fatty acid (FA) elongation. However, loss of PTPLA function increased VLCFA levels, an effect that was dependent on the presence of PAS2 indicating that PTPLA activity repressed FA elongation. The two dehydratases have specific expression profiles in the root with PAS2, mostly restricted to the endodermis, while PTPLA was confined in the vascular tissue and pericycle cells. Comparative ectopic expression of PTPLA and PAS2 in their respective domains confirmed the existence of two independent elongase complexes based on PAS2 or PTPLA dehydratase that are functionally interacting. PMID:27583779

  7. Evaluation of biocompatibility and toxicity of biodegradable poly (DL-lactic acid) films.

    Li, Rui-Yun; Liu, Zhi-Gang; Liu, Huan-Qiu; Chen, Lei; Liu, Jian-Feng; Pan, Yue-Hai

    2015-01-01

    Regeneration and functional recovery of nerves after peripheral nerve injury is the key to peripheral nerve repair. One of the putative therapeutic strategies is to use anti-adhesion polymer films, made of polymeric biomaterials. Recently, a novel biodegradable poly (DL-lactic acid) (PDLLA) film has been prepared using a method of phase transformation with biodegradable polylactic acid polymer as the substrate. This novel, anti-adhesion film has a porous structure, which provides better mechanical properties, better flexibility, more complete diffusion through the polymer of tissue biologic factors like growth factors, and more controllable degradation compared to traditional non-porous films. Little is known, however, about the in vitro and in vivo biocompatibility and cytotoxicity of this type of PDLLA film. Therefore, our aim was to evaluate the biocompatibility and cytotoxicity of this novel PDLLA film using various experimental methods, including a skin irritation test, MTT analysis, and the mouse bone marrow cell micronucleus test, as well as hematology or clinical chemistry measurements in rats after receiving sciatic nerve transection and anastomosis with wrapping of the anastomosis with DLLA films. We demonstrated that exposure to PDLLA film extracts did not generate apparent erythema or edema in rabbit skin and had no effect on the proliferation of Vero cells. Additionally, treatment with PDLLA film extracts did not alter the incidence of micronucleated polychromatic erythrocytes as compared with saline Treated group. Furthermore, implantation of PDLLA film did not alter liver or renal function as measured by serum levels of ALT, AST, TP, A/G, Cr, and BUN, and pathologic examinations showed that implantation of PDLLA film did not cause pathologic changes to the rat liver, kidney, pancreas, or spleen. Taken together, these results suggest that PDLLA films have excellent biocompatibility and no obvious toxicity in vivo, and may be used to prevent nerve

  8. Fabrication of superhydrophobic surface of hierarchical ZnO thin films by using stearic acid

    Wang, Yanfen; Li, Benxia; Xu, Chuyang

    2012-01-01

    Flower-like hierarchical ZnO microspheres were successfully synthesized by a simple, template-free, and low-temperature aqueous solution route. The morphology and microstructure of the ZnO microspheres were examined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The bionic films with hydrophobicity were fabricated by the hierarchical ZnO microspheres modified by stearic acid. It was found that the hydrophobicity of the thin films was very sensitive to the added amount of stearic acid. The thin films modified with 8% stearic acid took on strong superhydrophobicity with a water contact angle (CA) almost to be 178° and weak adhersion. The remarkable superhydrophobicity could be attributed to the synergistic effect of micro/nano hierarchical structure of ZnO and low surface energy of stearic acid.

  9. Cataluminescence sensor for gaseous acetic acid using a thin film of In2O3

    We report on a cataluminescence sensor for the determination of gaseous acetic acid. It is based on a 60-nm thick sol-gel film of In2O3 on a ceramic support. SEM, XPS and surface profiling were applied for its characterization. It is found that aluminum ions of the ceramic substrate penetrate into the film and produce a synergetic catalytic effect. The sensor displays high sensitivity and specificity for acetic acid, a low detection limit, a wide linear range and a fast response. No (or only very low) interference was observed by formic acid, ammonia, acrolein, benzene, formaldehyde, ethanol, and acetaldehyde. The sensor was successfully applied to the determination of acetic acid in spiked air samples. We also discuss a conceivable mechanism (based on the reaction products) for the cataluminescence resulting from the oxidation reaction on the surface of the sensor film. (author)

  10. Chitosan-gum arabic polyelectrolyte complex films: physicochemical, mechanical and mucoadhesive properties.

    Sakloetsakun, Duangkamon; Preechagoon, Detpon; Bernkop-Schnürch, Andreas; Pongjanyakul, Thaned

    2016-08-01

    By blending chitosan (CS) and gum arabic (GA), a powerful biomaterial complex might be obtained due to the unique properties of CS and the low viscosity and good emulsifying properties of GA. The objectives of this study were to prepare and examine the properties of dispersions and films of CS and GA as a function of the mixing weight ratio, pH value and molecular weight of CS. The dispersions were characterized by turbidity, zeta potential and cytotoxicity and then the dispersions were cast into films. Physicochemical properties of the film were performed. CS-GA dispersions exhibited higher turbidity and a lower zeta potential with an increase in the GA ratio. Continuous films of the CS-GA could be formed at all ratios. CS and GA could molecularly interact via electrostatic forces and intermolecular hydrogen bonding. The CS-GA (1:0.5) films exhibited relatively low water uptake, erosion, water vapor permeability and puncture strength compared to the CS films. Furthermore, the CS-GA films demonstrated good mucoadhesive properties, allowing for adhesion to the mucosal membrane. Based on these results, it could be advantageous to use CS-GA films as film formers for the formulation of coatings and drug delivery systems. PMID:25886079

  11. Synthesis of cadmium sulphide in pure and mixed Langmuir-Blodgett films of -octadecylsuccinic acid

    G Hemakanthi; Balachandran Unni Nair; Aruna Dhathathreyan

    2000-04-01

    Cadmium sulphide (CdS) nanoparticles were grown by the reaction of sodium sulphide (Na2S) with Langmuir-Blodgett (LB) films of cadmium salts of -octadecylsuccinic acid (ODSU) and with LB films of ODSU in mixtures of octadecylamine and octadecyl alcohol. The results indicate that heterogeneous nucleation and aggregation in the pure ODSU LB films due to processes like Ostwald ripening are destabilized by the presence of the long-chain amine and alcohol in mixed systems. CdS nanoparticles in the LB films were monitored by UV-visible absorption spectra, which allow an estimation of the size of the particles. The morphology, size and nature of the nanocrystallites formed depend on whether the sulphidation was done on the pure film or in the mixed films. It is seen that particles of size around 1.6 nm were formed in ODSU/octadecylalcohol and ODSU/octadecylamine mixed LB films while in pure ODSU films the size was about 2.7 nm. These films showed typical needle-shaped structures, as observed by the optical microscopic technique. Mean size and morphology were confirmed by transmission and scanning electron microscopy, while selective area electron diffraction patterns showed six-fold symmetry and indicated that the CdS crystals grow epitaxially with respect to the monolayer. Further, the crystallisation enhanced in the mixed LB films showed a characteristic zinc oxide (Wurtzite) structure compared with the pure ODSU matrix.

  12. Biodegradation of poly(hydroxy butanoic acid) copolymer mulch films in soil

    Kukade, Pranav

    Agricultural mulch films that are used to cover soil of crop rows contribute to earlier maturation of crops and higher yield. Incineration and landfill disposals are the most common means of disposal of the incumbent polyethylene (PE) mulch films; however, these are not environment friendly options. Biodegradable mulch films that can be rototilled into the soil after crop harvest are a promising alternative to offset problems such as landfill disposal, film retrieval and disposal costs. In this study, an in-house laboratory scale test method was developed in which the rate of disintegration, as a result of biodegradation of films based on polyhydroxybutanoic acid (PHB) copolymers was investigated in a soil environment using the residual weight loss method. The influence of soil composition, moisture levels in the soil, and industry-standard anti-microbial additive in the film composition on the rate of disintegration of PHB copolymer films was investigated. The soil composition has significant effect on the disintegration kinetics of PHB copolymer films, since the increasing compost levels in the soil lowered the rate of disintegration of the film. Also, with the increase in moisture level up to a threshold limit, the microbial activity and, hence, the rate of disintegration increased. Lastly, the developed lab-scale test protocol was found to be sensitive to even small concentrations of industry-standard antimicrobial additive in the film composition.

  13. Comparative study of electroless nickel film on different organic acids modified cuprammonium fabric (CF)

    Zhao, Hang; Lu, Yinxiang

    2016-01-01

    Nickel films were grown on citric acid (CA), malic acid (MA) and oxalic acid (OA) modified cuprammonium fabric (CF) substrates via electroless nickel deposition. The nickel films were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Their individual deposition rate and electromagnetic interference (EMI) shielding effectiveness (SE) were also investigated to compare the properties of electroless nickel films. SEM images illustrated that the nickel film on MA modified CF substrate was smooth and uniform, and the density of nickel nuclei was much higher. Compared with that of CA modified CF, the coverage of nickel nuclei on OA and MA modified CF substrate was very limited and the nickel particles size was too big. XRD analysis showed that the nickel films deposited on the different modified CF substrates had a structure with Ni (1 1 1) preferred orientation. All the nickel coatings via different acid modification were firmly adhered to the CF substrates, as demonstrated by an ultrasonic washing test. The result of tensile test indicated that the electroless nickel plating on CF has ability to strengthen the CF substrate while causes limited effect on tensile elongation. Moreover, the nickel film deposited on MA modified CF substrate showed more predominant in EMI SE than that deposited on CA or OA modified CF.

  14. Ultrafine nanoporous palladium-aluminum film fabricated by citric acid-assisted hot-water-treatment of aluminum-palladium alloy film

    Hot-water-treatment has been adapted to fabricate ultrafine nanoporous palladium-aluminum film from aluminum-palladium alloy film. Using citric acid as a chelating agent, a precipitation of boehmite (aluminum oxide hydroxide, AlOOH) on the nanoporous palladium-aluminum film was suppressed. According to cross-sectional scanning transmission electron microscopy observations, the ligament/pore sizes of the prepared nanoporous film were considerably small (on the order of 10 nm). Since this fabrication method only requires aluminum alloy film and hot-water with chelating agent, the ultrafine nanoporous film can be prepared simply and environmentally friendly

  15. Ultrafine nanoporous palladium-aluminum film fabricated by citric acid-assisted hot-water-treatment of aluminum-palladium alloy film

    Takashi Harumoto; Yohei Tamura; Takashi Ishiguro

    2015-01-01

    Hot-water-treatment has been adapted to fabricate ultrafine nanoporous palladium-aluminum film from aluminum-palladium alloy film. Using citric acid as a chelating agent, a precipitation of boehmite (aluminum oxide hydroxide, AlOOH) on the nanoporous palladium-aluminum film was suppressed. According to cross-sectional scanning transmission electron microscopy observations, the ligament/pore sizes of the prepared nanoporous film were considerably small (on the order of 10 nm). Since this fabri...

  16. Syntheses,characteristics,and fluorescence properties of complexes of europium with benzoic acid and its derivatives

    ZHOU Zhongcheng; SHU Wangen; RUAN Jianming; HUANG Boyun; LIU Younian

    2004-01-01

    The binary complexes of europium with benzoic acid and its derivatives (phthalic acid, m-phthalic acid,o-aminobenzoic acid, salicylic acid, and sulfosalicylic acid) were synthesized and their compositions were identified by elemental analyses. UV and IR of the complexes have been investigated. The UV spectra indicated that the complexes' ultraviolet absorption were mainly the ligands' absorption. The IR spectra showed that the IR spectra of complexes are different from those of free ligands. The fluorescence properties of them were investigated by using luminescence spectroscopy, the results showed that only three complexes appear as better luminescence, they were Eu-benzoic acid,Eu-m-phthalic acid and Eu-phthalic acid, while the others exhibited the ligands' wideband emission.

  17. The application of layered double hydroxide clay (LDH)-poly(lactide-co-glycolic acid) (PLGA) film composites for the controlled release of antibiotics

    Chakraborti, Michelle; Jackson, John K.; Plackett, David;

    2012-01-01

    complexes in poly(lactic-co-glycolic acid) films resulted in a reduced burst phase of release and a slow continuous release for many weeks with effective antimicrobial amounts of VAN and SF released at later time points. Layered double hydroxide clays may be useful for controlled release applications at...... quantitation of the unbound fraction by UV/Vis absorbance or HPLC analysis. Drug release from layered double hydroxide clay/drug complexes dispersed in polymeric films was measured by incubation in phosphate-buffered saline (pH 7.4) at 37 °C using absorbance or HPLC analysis. Antimicrobial activity of drug...... sites requiring long-term antibiotic exposure as they maintain the drug in a non-degraded state and release effective amounts of drug over long time periods. LDH clay/drug complexes are amenable to homogenous dispersion in polymeric films where implant coating may be optimal or required....

  18. The structure study of boron carbonitride films obtained by use of trimethylamine borane complex

    Kosinova, M L; Fainer, N I; Maximovski, E A; Kuznetsov, F A

    2001-01-01

    Diffraction of synchrotron radiation (SR) was used to investigate crystalline structure and phase composition of thin films (1500-5000 A) of boron carbonitride. These films were synthesized by plasma-enhanced chemical vapor deposition using nontraditional volatile single source precursor trimethylamine borane complex (CH sub 3) sub 3 N centre dot BH sub 3 and its mixture with ammonia. The effect of the gas ratio and substrate temperature on chemical and phase composition as well as the structure of the films were investigated. The XRD peculiarities of texture films and ways of increasing sensibility of measurements were considered. A possibility of the information density rise of the thin film XRD was shown due to application of different methods for recording diffraction patterns.

  19. The response of quartz crystals coated with thin fatty acid film to organic gases

    We tried to apply a quartz crystal as a sensor by using the resonant frequency and the resistance properties of quartz crystals. Four kinds of fatty acids that have the same head groups were coated on the surfaces of the quartz crystals, and the shift of the resonant frequency and the resistance were observed based on the lengths of the tail groups. Myristic acid (C14), palmitic acid (C16), stearic acid (C18), and arachidic acid (C20) were deposited on the surfaces of quartz crystals by using the Langmuir-Blodgett (LB) method. As a result, the resonant frequency change was more sensitive to high molecular-weight fatty acids than to low molecular-weight ones. We also observed the effect of temperature on stearic acid LB films, and the response properties of quartz crystals coated with stearic-acid LB films to organic gases were investigated. As a result, the sensitivity of quartz crystals to organic gases was higher for higher molecular-weight gas, and we found that quartz crystals coated with stearic-acid LB film were more sensitive to organic gas than bare quartz crystals at room temperature

  20. Complex Nonlinear Deformation of Nanometer Intergranular Glassy Films in βSi3N4

    Chen, Jun; Ouyang, Lizhi; Rulis, Paul; Misra, Anil; Ching, W. Y.

    2005-01-01

    The mechanical properties of a model of Y-doped intergranular glassy film in silicon nitride ceramics are studied by large-scale ab initio modeling. By linking directly to its electronic structure, it is shown that this microstructure has a complex nonlinear deformation under stress and Y doping significantly enhances the mechanical properties. The calculation of the electrostatic potential across the film supports the space charge model in ceramic microstructures.

  1. Complex nonlinear deformation of nanometer intergranular glassy films in beta-Si3N4.

    Chen, Jun; Ouyang, Lizhi; Rulis, Paul; Misra, Anil; Ching, W Y

    2005-12-16

    The mechanical properties of a model of Y-doped intergranular glassy film in silicon nitride ceramics are studied by large-scale ab initio modeling. By linking directly to its electronic structure, it is shown that this microstructure has a complex nonlinear deformation under stress and Y doping significantly enhances the mechanical properties. The calculation of the electrostatic potential across the film supports the space charge model in ceramic microstructures. PMID:16384476

  2. Graphene oxide supported mononuclear aquaruthenium complex ultrathin films with enhanced photoelectric conversion and electrocatalytic water oxidation

    Graphical abstract: A electrostatic film composed of GO nanosheets and a Ru(II) complex on ITO exhibited quasi-reversible redox behaviors with rapid heterogeneous electron transfer dynamics, and remarkably improved electrocatalytic water oxidation and photoelectric conversion properties as compared with the electrodes with polyanionic being the support for the Ru(II) complex. Display Omitted -- Abstract: A new Ru(II) complex of [Ru(tpy)(Htip)(H2O)]2+ {tpy = 2,2′,2″-terpyridine, Htip = 2-(thiophen-2-yl)-1H-imidazo[4,5-f][1,10]-phenanthroline} is synthesized and characterized. A layer-by-layer deposition of equal amounts of graphene oxide (GO) and the Ru(II) complex on hydrophilic substrates through electrostatic attraction of these two components was evidenced by X-ray photoelectron and UV–visible absorption spectroscopy. Permeability of the film to the redox probe [Fe(CN)6]3−/4− was studied by cyclic voltammetry and electrochemical impedance spectroscopy. The films showed stable electrochemical and photoelectrochemical properties with photocurrent densities of 6.6 μA/cm2 being found for a monolayer film and 9.7 μA/cm2 for a 4-layer film, which is much improved as compared to GO monolayer alone and the film by using a polyanion instead of the GO. The enhanced electrocatalytic water oxidation properties of this hybrid film have also been demonstrated. Preliminary results of electrocatalytic water oxidation by this hybrid film is also reported

  3. Glass Difractive Optical Elements (DOEs with complex modulation DLC thin film coated

    Marina Sparvoli

    2008-09-01

    Full Text Available We developed a complex (amplitude and phase modulation Diffractive Optical Element (DOE with four phase levels, which is based in a glass substrate coated with DLC (Diamond Like Carbon thin film as the amplitude modulator. The DLC film was deposited by magnetron reactive sputtering with a graphite target and methane gas in an optical glass surface. The glass and DLC film roughness were measured using non destructive methods, such as a high step meter, Atomic Force Microscopy and Diffuse Reflectance. Other properties, such as refractive index of both materials were measured. The DOEs were tested using 632.8 nm HeNe laser.

  4. Relaxation Kinetic Study of Eudragit® NM30D Film Based on Complex Modulus Formalism

    Penumetcha, Sai Sumana; Byrn, Stephen R.; Morris, Kenneth R.

    2015-01-01

    This study is aimed at resolving and characterizing the primary (α) and secondary relaxations (β) in Eudragit® NM30D film based on apparent activation energies derived from complex modulus formalism using dielectric analysis (DEA). The glass transition (Tg) of the film was determined using differential scanning calorimetry (DSC). The α relaxation corresponding to Tg and the β relaxations occurring below Tg were probed using DEA. The occurrence of α and β relaxations in Eudragit® NM30D film wa...

  5. CVD of pure copper films from novel iso-ureate complexes.

    Willcocks, Alexander M; Pugh, Thomas; Hamilton, Jeff A; Johnson, Andrew L; Richards, Stephen P; Kingsley, Andrew J

    2013-04-21

    We report the synthesis and characterisation of a new family of copper(i) metal precursors based around alkoxy-N,N'-di-alkyl-ureate ligands, and their subsequent application in the production of pure copper thin films. The molecular structure of the complexes bis-copper(i)(methoxy-N,N'-di-isopropylureate) (1) and bis-copper(i)(methoxy-N,N'-di-cyclohexylureate)(5) are described, as determined by single crystal X-ray diffraction analysis. Thermogravimetric analysis of the complexes highlighted complex 1 as a possible copper CVD precursor. Low pressure chemical vapour deposition (LP-CVD) was employed using precursor 1, to synthesise thin films of metallic copper on ruthenium substrates under an atmosphere of hydrogen (H2). Analysis of the thin films deposited at substrate temperatures of 225 °C, 250 °C and 300 °C, respectively, by SEM and AFM reveal the films to be continuous and pin hole free, and show the presence of temperature dependent growth features on the surface of the thin films. Energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD) and X-ray photoelectron spectroscopy (XPS) all show the films to be high purity metallic copper. PMID:23425976

  6. Effects of humic acid-metal complexes on hepatic carnitine palmitoyltransferase, carnitine acetyltransferase and catalase activities

    Fungjou Lu; Youngshin Chen (National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Biochemistry); Tienshang Huang (National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Medicine)

    1994-03-01

    A significant increase in activities of hepatic carnitine palmitoyltransferase and carnitine acetyltransferase was observed in male Balb/c mice intraperitoneally injected for 40 d with 0.125 mg/0.1 ml/d humic acid-metal complexes. Among these complexes, the humic acid-As complex was relatively effective, whereas humic acid-25 metal complex was more effective, and humic acid-26 metal complex was most effective. However, humic acid or metal mixtures, or metal such as As alone, was not effective. Humic acid-metal complexes also significantly decreased hepatic catalase activity. A marked decrease of 60-kDa polypeptide in liver cytoplasm was also observed on SDS-polyacrylamide gel electrophoresis after the mice had been injected with the complexes. Morphological analysis of a histopathological biopsy of such treated mice revealed several changes in hepatocytes, including focal necrosis and cell infiltration, mild fatty changes, reactive nuclei, and hypertrophy. Humic acid-metal complexes affect activities of metabolic enzymes of fatty acids, and this results in accumulation of hydrogen peroxide and increase of the lipid peroxidation. The products of lipid peroxidation may be responsible for liver damage and possible carcinogenesis. Previous studies in this laboratory had shown that humic acid-metal complex altered the coagulation system and that humic acid, per se, caused vasculopathy. Therefore, humic acid-metal complexes may be main causal factors of not only so-called blackfoot disease, but also the liver cancer prevailing on the southwestern coast of Taiwan.

  7. Highly Sensitive Bisphenol-A Electrochemical Aptasensor Based on Poly(Pyrrole-Nitrilotriacetic Acid)-Aptamer Film.

    Kazane, Imen; Gorgy, Karine; Gondran, Chantal; Spinelli, Nicolas; Zazoua, Ali; Defrancq, E; Cosnier, Serge

    2016-07-19

    An electrochemical highly sensitive aptasensor was developed based on electropolymerized poly(pyrrole-nitrilotriacetic) acid film and a new aptamer functionalized by a pentahistidine peptide for the quantification of bisphenol A. A surface coverage of antibisphenol A aptamer of 1.84 × 10(-10) mol cm(-2) was estimated from the electrochemical signal of the [Ru(III)(NH3)6](3+) complex bound by electrostatic interactions onto the aptamer-modified electrode. The binding of bisphenol A onto the polymer film was successfully characterized by electrochemical methods as square wave voltammetry and electrochemical impedance spectroscopy measurements. The designed label-free impedimetric aptasensor displayed a wide linear range from 10(-11) to 10(-6) mol L(-1) with a sensitivity of 372 Ω per unit of log of concentration and an excellent specificity toward interfering agents such as 4,4'-dihydroxybiphenyl and bisphenol P. PMID:27332710

  8. Fabrication of TiO2 nanoparticles/surfactant polymer complex film on glassy carbon electrode and its application to sensing trace dopamine

    A novel method for the fabrication of a TiO2/Nafion nano-film on glassy carbon electrode (NTGCE) is described. In the presence of dispersant, TiO2 nanoparticles were dispersed into water to give a homogeneous and stable suspension. After the solvent evaporation, a porous and uniform TiO2 nano-film was obtained on the GCE surface. Further coated with Nafion, the complex film possesses remarkable stability in aqueous solution. This nano-film was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The prepared electrode showed excellent electrocatalytic behavior of dopamine and high concentration of ascorbic acid does not interfere with the dopamine detection. Based on this, an electrochemical method is developed for the determination of dopamine with simplicity and high sensitivity

  9. Complex formation of Eu(III) with polyacrylic acid

    For the quantitative description of the interaction of metal ions with humic substances, it is necessary to clarify the effects of both polyelectrolyte and heterogeneous nature of humic substances. To estimate the polyelectrolyte effect separately, polyacrylic acid (MW = 90 000) has been selected as a representative of well-defined, homogeneous polymeric weak acids, and its interaction with Eu(III) has been investigated by a solvent extraction method using 152Eu (∝ 10-8 M) with TTA and TBP in xylene. By defining the apparent complex formation constant as βα = [ML]/([M][R]), where [M] = [Eu3+], [ML] is the concentration of Eu(III) associated with polyacrylic acid and [R] = CRα (CR is a total concentration of proton exchanging sites and α is a degree of dissociation determined by potentiometric titration), the apparent constants have been obtained at several pcH and ionic strength (0.1 M and 1.0 M NaClO4). The constants increased with pcH and decreased with an increase of ionic strength, that is, the values of log βα varied from 6.0 (at pcH = 4.7) to 7.6 (pcH = 5.5) at 0.1 M NaClO4 and from 4.8 (pcH = 4.4) to 6.5 (pcH = 5.4) at 1.0 M. The plots of log βα versus log α revealed almost linear relationship both at 0.1 and 1.0 M NaClO4. (orig.)

  10. Application of Lemongrass Oil-Containing Polylactic Acid Films to the Packaging of Pork Sausages

    2016-01-01

    Polylactic acid (PLA) is a biodegradable and renewable polymer, which represents a valuable alternative to plastic packaging films, often associated with environmental problems. In this study, we tested the suitability of PLA as a biodegradable packaging film and assessed the antimicrobial activity of lemongrass oil (LO), incorporated into the PLA film in different concentrations. To obtain the optimal physical properties for PLA films, tensile strength, elongation at break, and water vapor permeability were measured under different preparation conditions. In addition, the antimicrobial activity of the LO contained in the PLA film against Listeria monocytogenes was investigated by disc diffusion and viable cell count. Among all concentrations tested, 2% LO was the most suitable in terms of antimicrobial activity and physical properties of the PLA film. Based on these results, we used the PLA film containing 2% LO to pack pork sausages; after 12 d of storage at 4℃, the population of inoculated L. monocytogenes in the sausage samples wrapped with the PLA film containing 2% LO was reduced by 1.47 Log CFU/g compared with the control samples. Our data indicate that PLA films containing 2% LO represent a valuable means for antimicrobial sausage packaging. PMID:27433114

  11. Platinum thin film anodes for solid acid fuel cells

    Louie, Mary W.; Haile, Sossina M.

    2011-01-01

    Hydrogen electro-oxidation kinetics at the Pt | CsH_2PO_4 interface have been evaluated. Thin films of nanocrystalline platinum 7.5–375 nm thick and 1–19 mm in diameter were sputtered atop polycrystalline discs of the proton-conducting electrolyte, CsH_2PO_4, by shadow-masking. The resulting Pt | CsH_2PO_4 | Pt symmetric cells were studied under uniform H_2-H_2O-Ar atmospheres at temperatures of 225–250 °C using AC impedance spectroscopy. For thick platinum films (>50 nm), electro-oxidation o...

  12. Electrical properties of biodegradable poly(ε-caprolactone): lithium thiocyanate complexed polymer electrolyte films

    Graphical abstract: - Highlights: • The minimum Tm and χc values are observed in 15 wt% LiSCN complexed film. • The conductivity of PCL:LiSCN complexed films follows Johnscher's power law. • Conductivity and dielectric constant follows the same trend. • The charge carriers responsible for both conduction and relaxation are the same. - Abstract: Lithium ion conducting polymer electrolyte films based on biodegradable poly(ε-caprolactone) (PCL) complexed with lithium thiocyanate (LiSCN) salt were prepared by solution cast technique. Thermal and electrical properties of the polymer electrolyte films were studied using differential scanning calorimetry (DSC) and ac impedance spectroscopy. In order to investigate the ion conduction mechanism and relaxation behavior of complex polymer electrolyte films, the conductivity, dielectric constant, loss tangent and electric modulus were analyzed as a function of frequency and temperature. The variation of conductivity with frequency obeyed the Johnscher's power law. The dielectric constant exhibited a higher value at a lower frequency and increased with rising temperature due to the polar nature of host polymer. The activation energies for both dc conductivity and relaxation had the same value (∼0.87 eV), implying that the charge carriers responsible for both conduction and relaxation were the same

  13. Electrochromic iridium oxide films: Compatibility with propionic acid, potassium hydroxide, and lithium perchlorate in propylene carbonate

    Wen, Rui-Tao; Niklasson, Gunnar A.; Granqvist, Claes G.

    2013-01-01

    Porous thin films of It oxide were prepared by reactive dc magnetron sputtering onto unheated substrates. The crystallite size was similar to 5 nm, and a small amount of unoxidized Ir was present. The electrochromic performance was studied by optical transmittance measurements and cyclic voltammetry applied to films in aqueous and non-aqueous electrolytes, specifically being 1 M propionic acid, 1 M potassium hydroxide (KOH), and 1 M lithium perchlorate in propylene carbonate (Li-PC). Cyclic v...

  14. Synthesis and spectroscopic characterization of fluorescent solid rare earth complexes with hydroxamic acids

    2002-01-01

    The complexes RE2(DHYA)3 .nH2O in the title bar were synthesized through some reactions oftrivalent rareearth ions. In the process of synthesis, dihydroxamic acids were taken as ligands while the alcohol was taken as a solvent.The ligands included adipylhydroxamic acid (ADHA), p-phthalichydroxamic acid (PPHA), oxalohydroxamic acid (OXHA), butadihydroxamic acid (BDHA), o-phthalichydroxamic acid (OPHA), benzoylhydroxamic acid (BHA), etc.Measured at 25 ℃, the molar conductances in various modes are 13.00-21.05 S. cm2. mol-1, which shows that rare-earth complexes are nonelectrolytes and the hydroxamino groups of the complexes have taken part in bonding. Infrared spectra, ultraviolet spectra, nuclear magnetic resonance (1HNMR) spectra, and fluorescence spectra were used to investigate the complexes. Experiments have proved that the complexes of Eu3+ and Tb3+ with aromatic hydroxamic acids have good fluorescent characteristics.

  15. Photophysical characterization of layer-by-layer self-assembled films of deoxyribonucleic acid

    D Dey; S A Islam; S A Hussain; D Bhattacharjee

    2008-08-01

    This communication reports the photophysical characterization of self-assembled layer-by-layer (LbL) films of DNA (deoxyribonucleic acid) fabricated at different temperatures by electrostatic interaction with a polycation, poly(allylamine hydrochloride). It was observed that there was a successful incorporation of DNA molecules in DNA–PAH LbL films at room temperature as well as after melting temperature. An abrupt increase in intensity was observed in the absorption spectra of the films fabricated at high temperature which is an indication of the immobilization of unzipped DNA after melting of DNA. The films were observed to remain unaffected even after 250 h of film fabrication. The total electrostatic interaction time between DNA and PAH is about 15 min, that is, no PAH binding site is free.

  16. Microwave complex conductivity of the YBCO thin films as a function of static external magnetic field

    Krupka, J.; Judek, J.; Jastrzebski, C.; Ciuk, T.; Wosik, J.; Zdrojek, M.

    2014-03-01

    A sapphire rod resonator operating at microwave frequencies was used to determine the electric properties of 600 nm thick YBCO films in the superconducting state. The rigorous electromagnetic modelling was applied to transform the measured Q-factor and the resonant frequency to the complex conductivity of high accuracy, which was previously shown to describe the intrinsic properties of superconductor thin films in more precise manner than the complex impedance. Static external magnetic field induces typical transition to normal state due to introduction of magnetic vortices into the sample. Observed magnetic hysteresis has the origin in the strong temperature dependent pinning. Additional energy absorption at about 1.5 T was observed.

  17. Transition Metal–α-Amino Acid Complexes with Antibiotic Activity against Mycobacterium spp.

    Karpin, George W.; Merola, Joseph S.; Joseph O. Falkinham

    2013-01-01

    Synthetic iridium-, rhodium-, and ruthenium-amino acid complexes with hydrophobic l-amino acids have antibiotic activity against Mycobacterium spp., including Mycobacterium bovis BCG and the rapidly growing species Mycobacterium abscessus and Mycobacterium chelonae. Concentrations of transition metal-amino acid complexes demonstrating hemolysis or cytotoxicity were 10- to 25-fold higher than were the MICs.

  18. Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

    Hernandez-Espejel, A. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, CICATA-Unidad Altamira-Tamaulipas, km 14.5, Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira, Tamps (Mexico); Cabrera-Sierra, R. [Instituto Politecnico Nacional, Departamento de Ingenieria Quimica Industrial, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Rodriguez-Meneses, C. [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico); Arce-Estrada, E.M., E-mail: earce@ipn.m [Instituto Politecnico Nacional, Departamento de Ingenieria Metalurgica, IPN-ESIQIE, UPALM Ed. 7, Zacatenco 07738, Mexico, D.F. (Mexico)

    2010-07-15

    Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

  19. Investigations of corrosion films formed on API-X52 pipeline steel in acid sour media

    Corrosion films formed by voltammetry using different switching potentials and by immersion on API-X52 pipeline steel in simulated acid sour media (NACE ID182) have been characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Linear Polarization and Electrochemical Impedance Spectroscopy (EIS) techniques. XRD and EDS analysis showed that the films are mainly composed of sulphide compounds (mackinawite, troilite, marcasite and pyrite) as well as iron oxides, as steel damage increases. Across SEM micrographs the corrosion films formed by potentiodynamic and immersion tests are very similar, covering most of the steel. Polarization and EIS results corroborate poor behavior against corrosion.

  20. Comparative evaluation on fatty acid and Matricaria recutita essential oil incorporated into casein-based film.

    Aliheidari, Nahal; Fazaeli, Mahboubeh; Ahmadi, Reza; Ghasemlou, Mehran; Emam-Djomeh, Zahra

    2013-05-01

    Sodium caseinate composite films containing lipids-oleic acid (OA), stearic acid (SA), or Matricaria recutita essential oil (MEO) - were prepared through emulsification and their physical, thermal, mechanical, and barrier properties were evaluated and compared. Furthermore, their antimicrobial effectiveness against Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli was studied. Emulsified films were softer, less rigid, and more stretchable than pure films. The films' water vapor barrier properties were found to decrease upon the addition of lipid content; this effect was greatly reduced when MEO was added. The presence of OA/SA and MEO decreased tensile strength and elastic modulus but increased the elongation at break. Thermal analysis of all emulsified films showed two endothermic peaks; these results confirmed those obtained by SEM studies, where a partial separation of the two phases occurred. The films' antimicrobial activities were increased by incorporating lipids, particularly those containing MEO, which were more effective against the studied bacteria. This work showed that when taking all the studied variables into account, films formulated with MEO were found most suitable for various food applications. PMID:23415659

  1. Physicochemical Properties of Edible Chitosan/Hydroxypropyl Methylcellulose/Lysozyme Films Incorporated with Acidic Electrolyzed Water

    Ewa Brychcy

    2015-01-01

    Full Text Available The treatment with acidic electrolyzed water (AEW is a promising disinfection method due to its effectiveness in reducing microbial population. The aim of the study was to evaluate physicochemical properties of chitosan/HPMC films incorporated with lysozyme and acidic electrolyzed water. In the composite films, decreasing film solubility and increasing concentration of sodium chloride solution and prolongation of electrolysis time were observed. Electrolysis process with sodium chloride induces spongy network of film structure. The use of AEW has not changed chemical composition of films which was proved by 1H NMR, MALDI-TOF, and FT-IR spectroscopy. The research confirmed that electrolysis significantly improved thermomechanical properties of the examined films. The contact angle values of the films were quite similar and ranged between 56° and 73°. The increase of salt concentration used in the electrolysis process had an impact on increasing flexibility of samples. Application of electrolyzed water in commonly used food processing systems is possible. Fusion of AEW and biopolymers may provide better integration with coated food product and multidirectional protecting effect.

  2. The anodizing behavior of aluminum in malonic acid solution and morphology of the anodic films

    Ren, Jianjun; Zuo, Yu

    2012-11-01

    The anodizing behavior of aluminum in malonic acid solution and morphology of the anodic films were studied. The voltage-time response for galvanostatic anodization of aluminum in malonic acid solution exhibits a conventional three-stage feature but the formation voltage is much higher. With the increase of electrolyte concentration, the electrolyte viscosity increases simultaneously and the high viscosity decreases the film growth rate. With the concentration increase of the malonic acid electrolyte, the critical current density that initiates local "burning" on the sample surface decreases. For malonic acid anodization, the field-assisted dissolution on the oxide surface is relatively weak and the nucleation of pores is more difficult, which results in greater barrier layer thickness and larger cell dimension. The embryo of the porous structure of anodic film has been created within the linear region of the first transient stage, and the definite porous structure has been established before the end of the first transient stage. The self-ordering behavior of the porous film is influenced by the electrolyte concentration, film thickness and the applied current density. Great current density not only improves the cell arrangement order but also brings about larger cell dimension.

  3. Kinetics and mechanism of reduction of iron (III) kojic acid complex by ascorbic acid

    Kinetics of reduction of iron (III) kojic acid complex by ascorbic acid has been carried out using photodiode array spectrophotometer over the ranges: 4.0<=pH<=5.5 and 5.0<=T<=25.0 degree C at ionic strength 0.2 M under pseudo-first order conditions by stopped-flow technique. Rate of the reaction was found to be pH dependent. The redox reaction followed the saturation kinetics. The rate law is deduced as follows: Rate = (k/sub 3/k/sub eq(H/sup +/)(HAsc/sup -/)(Fe(KA)/sub 3/) / (HKA) + K/sub eq/(H/sup +/)(HAsc/sup -/) The activation parameters of this reaction were determined. A mechanism consistent with this rate law has been proposed. (author)

  4. Influence of the use of acids and films in post-harvest lychee conservation

    Danielle Fabíola Pereira da Silva

    2012-12-01

    Full Text Available Lychee (Litchi chinensis Sonn. has a high commercial value; however, it has a short shelf-life because of its rapid pericarp browning. The objective of this study was to evaluate the shelf-life of 'Bengal' lychee fruits stored after treatment with hydrochloric acid and citric acid, associated with cassava starch and plastic packaging. Uniformly red pericarp fruits were submitted to treatments: 1-(immersion in citric acid 100 mM for 5 minutes + cassava starch 30 g L-1 for 5 minutes, 2-(immersion in hydrochloric acid 1 M for 2 minutes + starch cassava 30 g L-1 for 5 minutes, 3-(immersion in citric acid 100 mM for 5 minutes + polyvinyl chloride film (PVC, 14 µm thick and 4-(immersion in hydrochloric acid 1 M for 2 minutes + PVC film. During 20 days, the fruits were evaluated for mass loss, pericarp color, pH, soluble solids and titratable acidity, vitamin C of the pulp and pericarp and activities of polyphenol oxidase and peroxidase of the pericarp. The treatment with hydrochloric acid associated with PVC was the most effective in maintaining the red color of the pericarp for a period of 20 days and best preservation of the fruit. The cassava starch associated with citric acid, and hydrochloric acid did not reduce the mass loss and did not prevent the browning of lychee fruit pericarp.

  5. Ultra-Thin Films of Poly(acrylic acid)/Silver Nanocomposite Coatings for Antimicrobial Applications

    Alaa Fahmy; Eisa, Wael H.; Mohamed Yosef; Ali Hassan

    2016-01-01

    In this work not only colloids of poly(acrylic acid) (PAA) embedded with silver nanoparticles (Ag-NPs) but thin films (10 nm) also were deposited using electrospray deposition technique (ESD). A mixture of sodium borohydride (NaBH4) and ascorbic acid (AA) were utilized to reduce the silver ions to generate Ag-NPs in the PAA matrix. Moreover, sodium tricitrate was used to stabilize the prepared colloids. The obtained colloids and films were characterized using UV-visible, transmission electron...

  6. Refractive index modulation in polymer film doped with diazo Meldrum's acid

    Zanutta, Alessio; Villa, Filippo; Bertarelli, Chiara; Bianco, Andrea

    2016-08-01

    Diazo Meldrum's acid undergoes a photoreaction induced by UV light and it is used as photosensitizer in photoresists. Upon photoreaction, a change in refractive index occurs, which makes this system interesting for volume holography. We report on the sublimation effect at room temperature and the effect of photoirradiation on the refractive index in thin films of CAB (Cellulose acetate butyrate) doped with different amount of diazo Meldrum's acid. A net modulation of the refractive index of 0.01 is achieved with 40% of doping ratio together with a reduction of the film thickness.

  7. Complex Formation of Selected Radionuclides with Ligands Commonly Found in Ground Water: Low Molecular Organic Acids

    Jensen, Bror Skytte; Jensen, H.

    1985-01-01

    A general approach to the analysis of potentiometric data on complex formation between cations and polybasic amphoteric acids is described. The method is used for the characterisation of complex formation between Cs+, Sr2+, Co2+, La 3+, and Eu3+ with a α-hydroxy acids, tartaric acid and citric acid......, and with the α-amino acids, aspartic acid and L-cysteine. The cations have been chosen as typical components of reactor waste, and the acids because they are often found as products of microbial activity in pits or wherever organic material decays...

  8. Electrical Transport in Nanoscale Complex Oxide Thin Films: Strontium titanate and RNiO3

    Son, Junwoo

    Complex oxide thin films have attracted significant attention due to a wealth of physical phenomena, such as ferroelectricity and Mott transitions arising from strong interactions in d-bands. Moreover, the physical phenomena observed in these materials exhibit sensitivities, which are not found in conventional semiconductors and give rise to abrupt changes in their physical properties. The richness of electronic phases and unique functionalities of complex oxides are attractive for applications in next-generation electronic devices. To realize new electronic devices with complex oxides, it is essential to understand the mechanisms of the electrical transport and to control the transport properties of complex oxide thin films. In this dissertation, electrical transport phenomena and their electrical control are experimentally studied in two different complex oxide thin film systems, exhibiting resistive switching and Mott metal-insulator transitions. The first part will briefly discuss resistive switching in ultrathin SrTiO3 tunnel junctions in metal-insulator-metal (MIM) geometry. The current-voltage characteristics provide hints of the origin of the resistive switching phenomena in SrTiO3 tunnel barriers, which are also relevant for resistive switching in thicker films. The second part focuses on the control of metal-insulator transitions in RNiO3, where R = trivalent rare earth ion, using different strategies: band-width control and band-filling control. The electrical transport in low-dimensional, strongly correlated LaNiO3 is explored in terms of band-width control by strain and dimensionality. A new concept of band-filling control in nanoscale NdNiO3 thin films by modulation doping is discussed, and the experimental charge injection from high-quality La-doped SrTiO3 into NdNiO3 thin films is experimentally studied. The potential and limitations of a Modulation-doped Mott Field Effect Transistor (MM-FET) for future "Mott" electronic devices is discussed.

  9. Zn/Al complex-SWCNT ink for transparent and conducting homogeneous films by scalable bar coating method

    Kukobat, Radovan; Hayashi, Takuya; Matsuda, Takafumi; Sunaga, Motoo; Sakai, Toshio; Futamura, Ryusuke; Kaneko, Katsumi

    2016-04-01

    It is shown that the viscosity of SWCNT inks is essential to produce highly homogeneous SWCNT films on the PET substrate with bar coating method. The Zn/Al complex-aided SWCNT ink has a viscosity threshold of 1.30 mPa s for the preparation of homogeneous films. The local flows of the film are suppressed above this viscosity, allowing homogeneous film formation. The Zn/Al complex dispersant can be easily removed from SWCNTs coated on PET by 1 M HNO3, giving a pure SWCNT film with the sheet resistance of 150 ohm/sq and transmittance of 90% at 550 nm immediately after HNO3 treatment.

  10. Porous poly(DL-lactic acid) matrix film with antimicrobial activities for wound dressing application.

    Chitrattha, Sasiprapa; Phaechamud, Thawatchai

    2016-01-01

    Poly(lactic acid) (PLA) is polymeric biomaterial that has been used for wound dressing due to its biodegradability and biocompatibility. However, PLA has some limitations including poor toughness, low degradation rate and high hydrophobicity. The aim of this study is to develop an antibiotic drug-loaded PLA porous film as wound dressing with antibacterial activity. PLA porous film was fabricated by temperature change technique using solvent casting method. Polyethylene glycol (PEG) 400 was added for improving the pore interconnectivity of film. Gentamicin sulfate (GS) or metronidazole (MZ) was incorporated into PLA porous films. PLA containing PEG 400 exhibited the more amorphous form than plain PLA film and contained 55.31 ± 2.85% porosity and 20 μm of the pore size which significantly improved the water vapor transmission rate, oxygen transmission rate, degradation rate and percentage of drug release, respectively. Drug-loaded porous films efficiently inhibited the bacteria growth. GS-loaded film inhibited Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, whereas MZ-loaded film inhibited Bacteroides fragilis and the sustainable antibacterial activity was attained for 7 days. PMID:26478412

  11. Preparation, characterization and evaluation of drug-delivery systems: Pectin and mefenamic acid films

    Moreira, R.B. [Universidade Federal de Mato Grosso, Rodovia MT-100, Km 3,5, Barra do Garças, MT CEP 78600-000 (Brazil); Teixeira, J.A. [Universidade Federal de Mato Grosso, Cuiabá, MT CEP 78060-900 (Brazil); Furuyama-Lima, A.M. [Universidade Estadual Paulista, IBILCE, São José do Rio Preto, SP CEP 15054-000 (Brazil); Souza, N.C. de [Universidade Federal de Mato Grosso, Rodovia MT-100, Km 3,5, Barra do Garças, MT CEP 78600-000 (Brazil); Siqueira, A.B., E-mail: buzutti@cpd.ufmt.br [Universidade Federal de Mato Grosso, Rodovia MT-100, Km 3,5, Barra do Garças, MT CEP 78600-000 (Brazil)

    2014-08-20

    Highlights: • The films were prepared and characterized by FTIR, TG–DSC/FTIR and AFM microscopy. • The results provided information on the composition, dehydration, thermal stability, thermal decomposition. • DSC results of CaHCl shows two overlapping endothermic peaks. • The AFM image shows great similarity for A5 and A6 films. • A5 and A6 films functioned well as a topical delivery system. - Abstract: Mefenamic acid (H-Mef) is a nonsteroidal anti-inflammatory drug (NSAID). Various adhesive dosage forms of NSAIDs have been developed, which include adhesive tablets, gels, ointments, patches and more recently, polymeric films. The objective of this study was the development of H-Mef adhesive films to be used as a drug-delivery system with different ratios of pectin and calcium chloride dihydrate by the casting technique. The materials were characterized by TG–DSC coupled FTIR, AFM (atomic force microscopy) and spectroscopic techniques. The results provided information about the dehydration, film roughness, surface morphology, thermal decomposition, as well as identification of gaseous products evolved during thermal decomposition. The characterizations indicated the A5 and A6 films functioned well, with 99% H-Mef released within 15 min at pH 5, suggesting these degradable films could be used as a topical delivery system.

  12. Preparation, characterization and evaluation of drug-delivery systems: Pectin and mefenamic acid films

    Highlights: • The films were prepared and characterized by FTIR, TG–DSC/FTIR and AFM microscopy. • The results provided information on the composition, dehydration, thermal stability, thermal decomposition. • DSC results of CaHCl shows two overlapping endothermic peaks. • The AFM image shows great similarity for A5 and A6 films. • A5 and A6 films functioned well as a topical delivery system. - Abstract: Mefenamic acid (H-Mef) is a nonsteroidal anti-inflammatory drug (NSAID). Various adhesive dosage forms of NSAIDs have been developed, which include adhesive tablets, gels, ointments, patches and more recently, polymeric films. The objective of this study was the development of H-Mef adhesive films to be used as a drug-delivery system with different ratios of pectin and calcium chloride dihydrate by the casting technique. The materials were characterized by TG–DSC coupled FTIR, AFM (atomic force microscopy) and spectroscopic techniques. The results provided information about the dehydration, film roughness, surface morphology, thermal decomposition, as well as identification of gaseous products evolved during thermal decomposition. The characterizations indicated the A5 and A6 films functioned well, with 99% H-Mef released within 15 min at pH 5, suggesting these degradable films could be used as a topical delivery system

  13. UV assisted photoelectrocatalytic oxidation of phthalic acid using spray deposited Al doped zinc oxide thin films

    Mahadik, M.A.; Shinde, S.S.; Hunge, Y.M.; Mohite, V.S.; Kumbhar, S.S.; Moholkar, A.V.; Rajpure, K.Y.; Bhosale, C.H., E-mail: chbhosale@gmail.com

    2014-10-25

    Highlights: • Nanostructured undoped and AZO thin films prepared by chemical spray pyrolysis. • Effect of Al doping on the structural, morphological and photoluminance properties. • Photocatalytic degradation of phthalic acid under UV light illumination. • Reaction kinetics and mineralization of phthalic acid. - Abstract: Undoped and Al doped ZnO (AZO) thin films are successfully prepared by spray pyrolysis technique at optimised substrate temperature of 400 °C onto amorphous and F:SnO{sub 2} coated glass substrates. Effect of Al doping on structural, morphological and optical properties of ZnO thin films is studied. Deposited films are polycrystalline with a hexagonal (wurtzite) crystal structure having (0 0 2) preferred orientation. The PEC characterization shows that, short circuit current (I{sub sc}) and open circuit voltage (V{sub oc}) are (I{sub sc} = 0.38 mA and V{sub oc} = 421 mV) relatively higher at the 3 at.% Al doping. SEM images show deposited thin films are compact and uniform with seed like grains. All films exhibit average transmittance of about 82% in the visible region and a sharp absorption onset at 375 nm corresponding to 3.3 eV. The photocatalytic activities of the large surface area (64 cm{sup 2}) Al-doped ZnO photocatalyst samples were evaluated by photoelectrocatalytic degradation of phthalic acid under UV light irradiation. The results show that the 3 at.% AZO thin film photocatalyst exhibited degradation of phthalic acid up to about 45% within 3 h with significant reduction in COD and TOC values.

  14. Complexation of metal ions with humic acid: metal ion charge neutralization model

    The humic acid complexation reaction presented in this work is based on the concept of metal ion charge neutralization upon complexation to humic acid functional groups. Experimental results from the complexation of UO22+, Am3+, and Cm3+ with humic acids of different origin are presented to demonstrate and validate the proposed model. By introducing the operational humic acid concentration and the loading capacity, the complexation constants are derived, which are independent of the metal ion concentration, pH, and origin of humic acid. The loading capacity is an operational term needed for the intercomparison of stability constants and is the mole fraction of the maximum available complexing sites of humic acid under a given set of experimental conditions. The metal ion charge neutralization model adequately describes the thermodynamic equilibrium reaction of metal ions with humic acid and allows a direct application of the resulting stability constants for geochemical modeling of actinide migration at an environmentally relevant pH. (orig.)

  15. Polyurethane films modified by antithrombin-heparin complex to enhance endothelialization: An original impedimetric analysis

    In this paper, polyurethane (PU) was deposited as a thin layer onto the surface of ITO (indium tin oxide) and was then modified with an antithrombin-heparin complex (ATH). The resulting films were characterized by ATR spectroscopy, contact angle measurements and electrochemical impedance spectroscopy (EIS). Physicochemical characterization confirmed the surface modifications. The obtained films were used as substrates for endothelial cell attachment and growth. These processes were characterized using electrochemical impedance spectroscopy (EIS). We observed that the addition of a small amount of heparin and AT additives onto the polymer surface resulted in a considerable change in the surface characteristics, and we found that PU films that were modified by the ATH complex were able to greatly enhance adhesion and proliferation of endothelial cells (ECs).

  16. Microscale and nanoscale hierarchical structured mesh films with superhydrophobic and superoleophilic properties induced by long-chain fatty acids

    Wang, Shutao; Song, Yanlin; Jiang, Lei

    2007-01-01

    Inspired by the lotus effect, we fabricate new microscale and nanoscale hierarchical structured copper mesh films by a simple electrochemical deposition. After modification of the long-chain fatty acid monolayer, these films show superhydrophobic and superoleophilic properties, which could be used for the effective separation of oil and water. The length of the fatty acid chain strongly influences the surface wettability of as-prepared films. It is confirmed that the cooperative effect of the hierarchical structure of the copper film and the nature of the long-chain fatty acid contribute to this unique surface wettability.

  17. Microscale and nanoscale hierarchical structured mesh films with superhydrophobic and superoleophilic properties induced by long-chain fatty acids

    Wang Shutao [Center for Molecular Science, Institute of Chemistry, Beijing 100080 (China); Song Yanlin [Center for Molecular Science, Institute of Chemistry, Beijing 100080 (China); Jiang Lei [Center for Molecular Science, Institute of Chemistry, Beijing 100080 (China)

    2007-01-10

    Inspired by the lotus effect, we fabricate new microscale and nanoscale hierarchical structured copper mesh films by a simple electrochemical deposition. After modification of the long-chain fatty acid monolayer, these films show superhydrophobic and superoleophilic properties, which could be used for the effective separation of oil and water. The length of the fatty acid chain strongly influences the surface wettability of as-prepared films. It is confirmed that the cooperative effect of the hierarchical structure of the copper film and the nature of the long-chain fatty acid contribute to this unique surface wettability.

  18. Microscale and nanoscale hierarchical structured mesh films with superhydrophobic and superoleophilic properties induced by long-chain fatty acids

    Inspired by the lotus effect, we fabricate new microscale and nanoscale hierarchical structured copper mesh films by a simple electrochemical deposition. After modification of the long-chain fatty acid monolayer, these films show superhydrophobic and superoleophilic properties, which could be used for the effective separation of oil and water. The length of the fatty acid chain strongly influences the surface wettability of as-prepared films. It is confirmed that the cooperative effect of the hierarchical structure of the copper film and the nature of the long-chain fatty acid contribute to this unique surface wettability

  19. Complex formation of Eu(III) with humic acid and polyacrylic acid

    With the intention of estimating the effect of the heterogeneous composition in the humic acid separately from its polyelectrolyte effect, comparative study on the interaction of Eu(III) with humic acid and polyacrylic acid has been carried out by the solvent extraction method with 10-3 M TTA and 10-3 M TBP in xylene at various total concentrations of Eu(III) (10-8 M to 10-5 M), pcH (5.0 to 5.5) and ionic strengths (0.02 to 1.0 M NaClO4). The interaction has been discussed in terms of the apparent complex formation constants, βα = [ML]/([M][R]), where [M] and [ML] are the concentrations of free and bound Eu3+ ion and [R] is the concentration of dissociated proton exchanging site. For both humate and polyacrylate, log βα increased with pcH or the degree of ionization and decreased with ionic strength. The Eu3+ ion concentration had no appreciable influence on the complex formation of Eu(III)-polyacrylate, and the values of log βα were obtained to be 7.57 ± 0.05 (I = 0.1, pcH = 5.53), 7.13 ± 0.04 (I = 0.1, pcH = 5.20), 6.68 ± 0.04 (I = 1.0, pcH = 5.54) and 5.61 ± 0.09 (I = 1.0, pcH = 4.73). On the other hand, log βα of humate remarkably decreased with the Eu3+ ion concentration; from 9.32 ([Eu3+] = 10-11.9 M) to 7.20 ([Eu3+] = 10-7.5 M) at pcH = 5.53 in 0.02 M NaClO4, from 8.63 ([Eu3+] = 10-12.5 M) to 6.35 ([Eu3+] = 10-7.2 M) at pcH = 5.53 in 0.1 M and from 7.59 ([Eu3+] = 10-10.7 M) to 5.20 ([Eu3+] = 10-7.0 M) at pcH = 5.52 in 1.0 M. The observed dependence of log βα of humate on the concentration of metal ion strongly suggests the heterogeneity of the complexing sites (the coexistence of weak and strong binding sites) in the humic acid. (orig.)

  20. Enhanced charge transport in highly conducting PEDOT-PSS films after acid treatment

    Shiva, V. Akshaya; Bhatia, Ravi; Menon, Reghu

    The high electrical conductivity, good stability, high strength, flexibility and good transparency of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS), make it useful for many applications including polymeric anodes for organic photovoltaics, light-emitting diodes, flexible electrodes, supercapacitors, electrochromic devices, field-effect transistors and antistatic-coatings. However, the electrical conductivity of PEDOT-PSS has to be increased significantly for replacement of indium tin oxide (ITO) as the transparent electrode in optoelectronic devices. The as prepared (pristine) PEDOT-PSS film prepared from the PEDOT-PSS aqueous solution usually has conductivity below 1Scm-1, remarkably lower than ITO. Significant conductivity enhancement has been observed on transparent and conductive PEDOT-PSS films after a treatment with inorganic acids. Our study investigates the charge transport in pristine and H2SO4, HNO3, HCl treated PEDOT-PSS films. We have treated the films with various concentrations of acids to probe the effect of the acid treatment on the conduction mechanism. The study includes the measurement of dc and electric field dependent conductivity of films in the temperature range of 4.2K-300K. We have also performed magneto-resistance measurements in the range of 0-5T. An enhancement by a factor of~103 has been observed in the room temperature conductivity. The detailed magneto-transport studies explain the various mechanisms for the conductivity enhancement observed.

  1. Preparation and Characterization of Films Extruded of Polyethylene/Chitosan Modified with Poly(lactic acid

    Jesús Manuel Quiroz-Castillo

    2014-12-01

    Full Text Available The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid, promoted by the compatibilizer.

  2. Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

    Puthirath, Anand B.; Methattel Raman, Shijeesh; Varma, Sreekanth J.; Jayalekshmi, S.

    2016-04-01

    Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

  3. Effects of deposition time in chemically deposited ZnS films in acidic solution

    Haddad, H.; Chelouche, A., E-mail: azeddinechelouche@gmail.com; Talantikite, D.; Merzouk, H.; Boudjouan, F.; Djouadi, D.

    2015-08-31

    We report an experimental study on the synthesis and characterization of zinc sulfide (ZnS) single layer thin films deposited on glass substrates by chemical bath deposition technique in acidic solution. The effect of deposition time on the microstructure, surface morphology, optical absorption, transmittance, and photoluminescence (PL) was investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV-Vis–NIR spectrophotometry and photoluminescence (PL) spectroscopy. The results showed that the samples exhibit wurtzite structure and their crystal quality is improved by increasing deposition time. The latter, was found to affect the morphology of the thin films as showed by SEM micrographs. The optical measurements revealed a high transparency in the visible range and a dependence of absorption edge and band gap on deposition time. The room temperature PL spectra indicated that all ZnS grown thin films emit a UV and blue light, while the band intensities are found to be dependent on deposition times. - Highlights: • Single layer ZnS thin films were deposited by CBD in acidic solution at 95 °C. • The effect of deposition time was investigated. • Coexistence of ZnS and ZnO hexagonal structures for time deposition below 2 h • Thicker ZnS films were achieved after monolayer deposition for 5 h. • The highest UV-blue emission observed in thin film deposited at 5 h.

  4. Stretchability of Silver Films on Thin Acid-Etched Rough Polydimethylsiloxane Substrates Fabricated by Electrospray Deposition

    Mehdi, S. M.; Cho, K. H.; Kang, C. N.; Choi, K. H.

    2015-07-01

    This paper investigates the fabrication of Ag films through the electrospray deposition (ESD) technique on sub-millimeter-thick acid-etched rough polydimethylsiloxane (PDMS) substrates having both low and high modulus of elasticity. The main focus of the study is on the stretchable behavior of ESD-deposited Ag nanoparticles-based thin films on these substrates when subjected to axial strains. Experimental results suggest that the as-fabricated films on thin acid-etched rough low modulus PDMS has an average stretchability of 5.6% with an average increase in the resistance that is 23 times that of the initial resistance at electrical failure (complete rupture of the films). Comparatively, the stretchability of Ag films on the high modulus PDMS was found to be 3 times higher with 4.65 times increase in the resistance at electrical failure. Also, a high positive value of the piezoresistive coefficient for these films suggests that the resistivity changes during stretching, and thus deviation from the simplified models is inevitable. Based on these results, new models are presented that quantify the changes in resistance with strain.

  5. Synthesis and characterization of rough electrochromic phosphotungstic acid films obtained by spray-gel process

    Rough electrochromic phosphotungstic acid (PWA) films were fabricated by spraying a gel of phosphotungstate anions with a molar ratio of P:W = 1:12 onto glass substrates precoated with transparent and electrically conducting SnO2:F at 300 oC. The analysis by X-ray photoelectron spectroscopy (XPS) determined that the P:W molar ratio in the films was approximately 1:14. Infrared spectroscopy (IR) and X-ray diffraction (XRD) showed that the film is a polycrystalline phosphotungstic acid. SEM micrographs showed that the films present a rough morphology based on fiber-shape bridges. Optoelectrochemical measurements demonstrated pronounced electrochromism in the PWA films upon H+ intercalation/deintercalation with a high diffuse reflectance (Rd) and transmittance (Td). We found for as-deposited films that Rd/total reflectance (Rt) and Td/total transmittance (Tt) at 550 nm was around 0.83 and 0.68, respectively. This ratio decreases at bleached state to 0.74 and 0.41 for Rd/Rt and Td/Tt, respectively. (authors)

  6. Effects of deposition time in chemically deposited ZnS films in acidic solution

    We report an experimental study on the synthesis and characterization of zinc sulfide (ZnS) single layer thin films deposited on glass substrates by chemical bath deposition technique in acidic solution. The effect of deposition time on the microstructure, surface morphology, optical absorption, transmittance, and photoluminescence (PL) was investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV-Vis–NIR spectrophotometry and photoluminescence (PL) spectroscopy. The results showed that the samples exhibit wurtzite structure and their crystal quality is improved by increasing deposition time. The latter, was found to affect the morphology of the thin films as showed by SEM micrographs. The optical measurements revealed a high transparency in the visible range and a dependence of absorption edge and band gap on deposition time. The room temperature PL spectra indicated that all ZnS grown thin films emit a UV and blue light, while the band intensities are found to be dependent on deposition times. - Highlights: • Single layer ZnS thin films were deposited by CBD in acidic solution at 95 °C. • The effect of deposition time was investigated. • Coexistence of ZnS and ZnO hexagonal structures for time deposition below 2 h • Thicker ZnS films were achieved after monolayer deposition for 5 h. • The highest UV-blue emission observed in thin film deposited at 5 h

  7. Quantum chemical prediction of paramagnetic NMR spectra of lanthanide complexes with salicylic acid in water solution

    17O and 13C paramagnetic NMR (PNMR) shifts have been calculated for Gd complexes with salicylic acid in water solution. These complexes served us as model compounds for simulation of more complicated lanthanide complexes with humic acids. The obtained data demonstrate that paramagnetic NMR spectra are very sensitive to the bonding details of the ligand. Our calculations suggest that formation of Gd(III) complex with salicylic acid in water solution via carboxyl group with uni-dentate coordination is preferable. New experimental studies with the enriched 17O and 13C nuclei of carboxylate groups of the salicylic and humic acids are extremely desirable

  8. Optical Absorption, Stability and Structure of NpO2+ Complexes with Dicarboxylic Acids

    Complexation of NpO2+ with oxalic acid (OX),2,2'-oxydiacetic acid (ODA), 2,2'-iminodiacetic acid (IDA) and 2,2'-thiodiacetic acid (TDA), has been studied using spectrophotometry in1 M NaClO4. Both the position and the intensity of the absorption band of NpO2+ at 980 nm are affected by the formation of NpO2+/dicarboxylate complexes, providing useful information on the complexation strength, the coordination mode and the structure of the complexes

  9. Complex modulation of androgen responsive gene expression by methoxyacetic acid

    Stanley Kerri A

    2011-03-01

    Full Text Available Abstract Background Optimal androgen signaling is critical for testicular development and spermatogenesis. Methoxyacetic acid (MAA, the primary active metabolite of the industrial chemical ethylene glycol monomethyl ether, disrupts spermatogenesis and causes testicular atrophy. Transcriptional trans-activation studies have indicated that MAA can enhance androgen receptor activity, however, whether MAA actually impacts the expression of androgen-responsive genes in vivo, and which genes might be affected is not known. Methods A mouse TM3 Leydig cell line that stably expresses androgen receptor (TM3-AR was prepared and analyzed by transcriptional profiling to identify target gene interactions between MAA and testosterone on a global scale. Results MAA is shown to have widespread effects on androgen-responsive genes, affecting processes ranging from apoptosis to ion transport, cell adhesion, phosphorylation and transcription, with MAA able to enhance, as well as antagonize, androgenic responses. Moreover, testosterone is shown to exert both positive and negative effects on MAA gene responses. Motif analysis indicated that binding sites for FOX, HOX, LEF/TCF, STAT5 and MEF2 family transcription factors are among the most highly enriched in genes regulated by testosterone and MAA. Notably, 65 FOXO targets were repressed by testosterone or showed repression enhanced by MAA with testosterone; these include 16 genes associated with developmental processes, six of which are Hox genes. Conclusions These findings highlight the complex interactions between testosterone and MAA, and provide insight into the effects of MAA exposure on androgen-dependent processes in a Leydig cell model.

  10. Influence of humic acid size on actinide complexation

    The complexation of Am(III) and Eu(III) with humic acid of different molecular sizes was measured and the data for the ≥300kD and ≥10kD sized HA at pcH 4.0 and 6.0 was analyzed by the Charge Neutralization Model (CNM) and the Polyelectrolyte Model (PM). For the PM, solvent extraction was used to obtain the stability constants of 241Am at tracer concentration. For the CNM, ultrafiltration was used to determine the loading capacity and the stability constants for Eu(III) at macro concentrations. There was a difference of 1-2 orders of magnitude in the stability constants from the two models. The 5D0-7F0 excitation spectra of Eu(III) as a function of loading of HA was found to have a shift in wavenumbers of the peak maximum, indicating that the coordination environment of Eu(III) varied with pH, presumably due to variation in the number of functional groups of the humate bound to the metal ion