ESCA Spectra Research Articles

Synthesis and characterization of polymeric, anionic thiosalicylato-Ag(I) complexes with antimicrobial activities

Thiosalicylic acid ligand (H 2TSA = o-HS(C 6H 4)COOH) forms two types of anionic light- and thermally stable Ag(I) complexes with remarkable antimicrobial activities for bacteria, yeast, and mold; one is a yellow, water-soluble complex 1 and the other an orange, water-insoluble complex 2, either of which can be converted to the other, and both of which do not crystallize. Both are complexes with composition of metal: TSA 2− ligand = 1:1. The complex 2 is probably polymeric, whereas the complex 1 is an oligomer with a formula of {Na[Ag(TSA 2−)·H 2O]} n(n = 12 − 14; MW = 3600 − 4200). Both complexes have been characterized with complete elemental analyses, TG/DTA, FT-IR, and ESCA spectra in the solid state, and complex 1 as well as with molecular weight measurement in aqueous solution, and with 109Ag and 2D NMR( 1H- 1H COSY, 1H- 13C COSY, and HMBC) measurements in aqueous solution.

Comments on: “Determination of numerical data from polychromatic ESCA spectra and their verification”

Comments on: “Determination of numerical data from polychromatic ESCA spectra and their verification”

Formation of Surface Structure in Vulcanizates and Surface Structure Changes in Air

Abstract The formation theory of surface structure during vulcanization was developed on the basis of an interfacial concept. The theory showed the chemical compositions of polar and nonpolar components on the vulcanizate surface to be determined as an excess interfacial free energy between rubber compounds and molds decreases. The surface free energies of molds reflected clearly the corresponding surface free energy of vulcanizates prepared from copolymers and polar polymers. Nonpolar polymers were not influenced by the surface free energies of molds. The surface free energies of vulcanizates decreased slightly with the concentration of network chains owing to the entropy of rubber segments. The surface free energies of molds affected the chemical compositions at the topmost surface region to the upper surface region on vulcanizates. NBR vulcanizates with high surface free energy increased the contact angle of water after standing in dry air. In the dry air environment, topmost surface layer nitrile groups were buried in the bulk of NBR vulcanizates and butadiene units subsequently overturn to the topmost, layer. In this case, the vulcanizate surface chemical composition was influenced only at the topmost surface region. ESCA spectra N1s peak intensities on NBR vulcanizates was consistent with these observation.

Effect of Surface Characteristics of Films and Fabrics Treated with Low-Temperature Plasmas under Atmospheric Pressure on Adhesive Property.

Six kinds of engineering plastic films (polypropylene, poly (ethylene terephthalate), polycarbonate, nylon 6, polyimide, and p-aramid) and five textile fabrics (polypropylene, polyester, nylon 6, wool, and m-aramid) were treated with atmospheric low-temperature plasmas in the presence of helium/argon and acetone/argon. Adhesion of the plasma-treated films and fabrics with adhesive tape by 180° peeling test was generally increased except for polyimide film. Surface characteristics of the films were investigated by means of SEM, ESCA, and critical surface tension. Surface tension and O1s intensity of the ESCA spectra increased by the plasma treatment.

Investigation on structure and morphology of the thermally treated glassy alloy (Fe,Cr)80(P,C,Si)20 by means of ESCA and SEM/EDXA

Metallic glass ribbons of the chemical composition (Fe,Cr)80(P,C,Si)20 have been thermally treated in the region between 530 and 980°C for 72 h. The SEM/EDXA investigations indicate that a phase transformation takes place between 575 and 980°C in a surface layer of 5 μm thickness. Thus, a Cr-rich phase occurs between 760 and 800°C which is converted into an open-pore system between 850 and 900°C. The oxidation process reaches its maximum at 760°C. The ESCA spectra of the material in the “as received” state and of the thermally treated samples indicate that different oxygen species are formed within the analysed surface layer of 10 nm. The oxygen of the original material is incorporated as hydroxyl groups in species such as FeO(OH) and CrO(OH). After thermal treating the hydroxyl content decreases and the oxide content increases. Species of Si exist in the surface layer as SiOx-like compounds (peak at BE=102.0 eV). A majority phase of transition metal phosphide species is coexisting with oxidised phosphate species.

Studies on the photoreaction of polysilanes by fluorescence spectroscopy

The fluorescence spectra of poly(methylcyclohexylsilane) (PCHMS) or poly-(methylphenethylsilane-co-methylcyclohexylsilane) (Copolymer) in solutions before and after u.v. irradiation in air were studied. The experimental results showed that the positions of the fluorescence peaks shifted to a shorter wavelength and the fluorescence intensities decreased gradually with an increase of u.v. exposure time. The dependences of u.v. spectra, GPC, ESCA spectra and i.r. spectra of PCHMS or Copolymer solutions upon u.v. exposure in air indicated that these phenomena are in accordance with the processes of photodegradation and photo-oxidation, which led to decreasing molecular weights and the formation of siloxane structure in silicon-silicon main chains.

Preparation and cuprous ion conducting properties of the glasses in the system CuICu 2WO 4CuPO 3

in the process of preparation of Cu + ion conducting glasses, a problem is posed by the spontaneous disproportionation Cu + to Cu 0 and Cu 2+ during melting. Since the stability of Cu + ions during melting relates to the acidity of the melt, we have tried the glass formation in the system CuICu 2WO 4CuPO 3, whose melt was expected to have high acidity. The ESCA spectrum indicated that copper ions in the glasses existed only as Cu + ions, and the CuICu 2WO 4CuPO 3 glasses obtained show high ion conductivity in the range of 10 −2 ∼ 10 −4 S cm −1 at room temperature.

Electronic structure of thiometalates [MS 4] n− (M=Mo, W, Re). XANES spectra and SCF-Xα-SW calculations

Sulfur K-edge XANES spectra of PPh 4 + salts of the title species are reported. Assignments for the characteristic positions in the spectra are given and discussed. The energies of the pre-edge peaks and the main absorption edges are used to determine the ‘crystal-field’ splitting energies Δ, i.e. the energy difference between the 2e and 4t 2 levels (1.4 eV for [ReS 4] −, 1.1 eV for [WS 4] 2− and [MoS 4] 2−) and the energies of some frontier orbitals (HOMO-LUMO region). These data are compared with results from Xα calculations, electronic absorption and ESCA spectra.

Surface Charactreistics of Polyphenylene Sulfide(PPS) Film Treated by Discharge Plasmas.

Polyphenylene sulfide film was treated with low-temperature oxygen, nitrogen, and argon plasmas; argon sputter etching, and low-temperature helium/argon plasma under atmospheric pressure, and then the surface characteristics were investigated by means of critical surface tension and ESCA measurement. Critical surface tension and the O 1S intensities in ESCA spectra were increased considerably after discharge treatments. By helium/argon atmospheric low-temperature plasma treatment, the N 1S and O 1S intensities increased remarkably. From wave form separation of C 1S and S 2p spectra, it was found that oxygens incorporated in the polymer are present in the forms of -C-O-, -COO-, -S(=0)-, and -S(=0) 2−

Photostabilization of photocrosslinked unsaturated polyesters

The photo-oxidative stability of photocrosslinked unsaturated polyesters endcapped with glycidyl acrylate has been investigated by measuring UV, IR and ESCA spectra of thin films and tensile properties of photocrosslinked glass fiber laminates of the polyesters without and with added stabilizers. When the resulting films and laminates are aged by irradiation in a UV-CON irradiator for various lengths of time, surface oxidation occurs to a certain level. The addition of 0·15–0·30% hindered amine stabilizer based on 2,2,6,6-tetramethylpiperidine, TINUVIN-770, TINUVIN-292 and TINUVIN-144 to the resins before crosslinking decreases the rate of surface oxidation and prevents the decrease in tensile strength that occurs due to aging without the addition of the stabilizers. TINUVIN-770 with NH groups is found to provide higher levels of stabilization in the UV crosslinked unsaturated polyester system than the other two stabilizers with NCH 3 groups, especially during the early stages of irradiation.

Synthetic conducting materials XII. TCNQ and polyiodide charge transfer salts with hexaazacyclotetradecine nickel complex donor

A hexa-aza-macrocyclic nickel(II) complex, Ni(HAPP), of large conjugated pi-system is readily obtained from template condesation of 2,9-diamino-1,10-phenanthroline with 2,9-dichloro-1,10-phenanthroline in the presence of the nickel(II) ion. Both of the charge transfer salts of Ni(HAPP) with TCNQ and polyiodide have been prepared and characterized by elemental analysis, infrared, electronic, and mass spectroscopy. The polyiodide existed in I5− form characterized by Raman spectroscopy. There are two steps decomposition of the I5− ion to eliminate I2, I5−—I3−—I−, when analyzed by thermal gravimetry. The differential thermal analytical results evidented that very weak interaction between Ni(HAPP) and I5− occured. the variable temperature magnetic susceptibility and electron paramagnetic resonance spectroscopy were employed to investigate the behavior of the unpaired electrons in the solid state crystal. An interesting detail of the magnetic susceptibility will be presented and discussed. The EPR spectra of these compoinds show a novel type of conjugated system, related to some extent to porphin and phthalocyanin. The ESCA spectra and electric conductivity have been measured and will be discussed.

Silicon oxide film preparation by RF plasma-enhanced MOCVD using hexamethyldisiloxane

Silicon oxide films were prepared in an RF capacitive plasma using hexamethyldisiloxane. The films deposited on c-Si, quartz plate, glass and polycarbonate at room temperature were studied by means of IR absorption, ESCA and optical transmission spectra. The processing plasmas were also monitored spectroscopically.

Modification of Cotton Fiber by Low Temperature Plasma.

Cotton fiber was modified by low temperature plasma of air, oxygen and argon. The modification speed with 13.56MHz-waves was faster than it was with 20KHz- waves. The modification speeds, in descending order, were as follows: oxygen>air>argon plasma.When the cotton fiber was modified by low temperature plasma treatment, flexual rigidity decreased and ductility increased. Water absorption increased, as did crease resistance, drying rate and degree of crystallinity. On the other hand, equilibrium moisture regain, K/S value of reactive dye and direct dye decreased. The soil release property developed through air and oxygen plasma treatment. From the ESCA spectra, it was found that the fiber surface quality was reformed from C-H bond C-O bond by argon plasma treatment. With weight loss 18.69% by air plasma treatment, tear strength retention of treated cotton broad was 73.8% in warp and 77.0% in fill.

Fluoroalkylation of Polyester Surface Part I. Fluoroalkylation of Polyester Surface with Block Copolymers Containing Fluoroalkyl Groups.

Polyester surface was modified with block copolymers containing fluoroalkyl groups. The surface of the modified polyester was characterized using contact angle measurements of a two-liquid-phase system and ESCA spectroscopy. The fluoroalkyl groups on the polyester surface influenced both dispersive and polar components of surface free energy, and both of them decreased with increasing treating temperature. The surface cover ratios based on the contact angles were linearly correlated to the relative peak intensities of F 1s peak in ESCA spectra and surface free energies as well. The effect of fluoroalkylation on soil release properties of fabrics was also investigated by the washing experiments using squalane, triolein and oleic acid as oily soils. Regardless of the kind of oily soil and washing liquor, the removal first decreased, and then increased with increasing fluorine content

Analysis of the Functional Groups Formed on the Corona-Treated Cellulose Fibre Sheet Surface by Means of Chemical Modification in Gas Phase-ESCA Technique.

The surfaces of corona-treated cellulose fibre sheets were characterized by a chemical modification in gas phase-ESCA technique. Whatman #1 filter paper, handsheets from softwood bleached sulfate pulp (N•BKP), handsheets from hardwood bleached sulfate pulp (L•BKP) and handsheets from thermomechanical pulp (TMP) were prepared as cellulose fibre sheet samples. The following results were obtained. (1) Corona-treated cellulose fibre sheets were chemically modified (derivatized) in gas phase by pentafluorophenylhydrazine (PFPH) or trifluoroethanol (TFE), and ESCA spectra of the derivatized sheets were examined. The results show that carbonyl and carboxyl groups were formed on the surface of the cellulose fibre sheets. (2) The quantity of the introduced carbonyl and carboxyl groups, which were obtained by derivatization in gas phase, was larger than those obtained by derivatization in liquid phase. Furthermore, the quantities of the functional groups formed on the surface of the sheets by derivatization in gas phase after washing with some organic solvents and those by washing with organic solvents after derivatization were found to be less than those derivatizing only in gas phase. These results suggest that carbonyl and carboxyl groups were introduced onto the framework or main chain in the surface layer of the sheets. At that time, depolymerization occurs in the framework and the resulting fragmental low molecular compounds have carbonyl and carboxyl groups. (3) The total concentration of the carbonyl and carboxyl groups in the ethanol extracts from the corona-treated sheet were determined by oxime formation and hydroxamic acid-Fe chelate complex formation method, respectively. The increase of 0.98% in the carboxyl group for Whatman #1 filter paper and that of 0.58% for TMP handsheet were found, compared with those of untreated sheets. The increase of 0.02% in the carboxyl group for the Whatman #1 filter paper and that of 0.04% for the TMP handsheet were also found. These results indicate that the low molecular compounds were formed by corona discharge and the compounds possess carbonyl or carboxyl groups.

Quantification in surface analysis

The quantitative separation of the overlapped ESCA spectra of some mixtures of powders of chromium and lead compounds was performed by the Kalman filter algorithm. Noise baselines below peak were drawn by using cubic spline polynomials as smooth interpolators. Typical errors in the estimated concentrations of the components were less than 8%.

Thin layers of gallium-arsenide: A molecular orbital study

The quasirelativistic INDO/1 method has been used to generate molecular orbitals for some {GaAs}n clusters up to 160 atoms. On the basis of these one-electron energy levels the density of states (DOS) and density of hole functions have been calculated. Various projections of DOS functions are discussed. The calculations are compared with those generated by periodic crystal orbitals of the EHT quality and with experimental ESCA spectra on thin layers of GaAs.

Determination of numerical data from polychromatic ESCA spectra and their verification

The main disadvantages of commonly used pragmatic procedures for the extraction of numerical data from polychromatic ESCA spectra are discussed. It is shown that physically defined models allow a proper description of polychromatic core-level spectra, when new parameters of the excitation function (Al Kα and Mg Kα) and a new background construction are used. The new background construction consists of a modified Tougaard background, with an additional parameter N, which account for no-loss regions, and a linear background. The appropriate line shapes are voigtians (atomic spectra), Doniach—Sunjić shapes convoluted with a gaussian shape (metallic samples) and experimentally determined singlet shapes, or Kuchiev-type shapes for the case of vibrationally non-resolved spectra of free and solid molecules. The data obtained may be verified by comparison with physically well-defined lorentzian and gaussian widths, spin-orbit splitting, etc., determined separately or taken from the literature. A statistical analysis of the residual spectra (here discussed for the first time) allows for the falsification of statistically unrealiable data.

Photoinitiated surface grafting of synthetic fibers, IV. Applications of textile dyes onto surface‐photografted synthetic fibers

AbstractHigh‐strength polyethylene (HSPE), polypropylene (PP), poly(ethylene terephthalate) (PET), and poly(vinyl alcohol) (PVA) textile yarns have been surface‐photografted with various functional monomers, such as acrylic acid (AA), acrylamide (AM), glycidyl acrylate (GA) and 4‐vinyl pyridine (VP), by means of the continuous presoaking process developed. The dyeing of these surface‐modified yarns with various textile dyes has been investigated. In general, considerable improvements of dyeability have been observed. The dye adsorption of the surface‐photografted fibers is influenced by many factors, such as type of fiber, amount and properties of the functional monomer grafted on the surface of the fibers, type of textile dye, etc. The fibers surface‐grafted with a monomer containing basic groups, such as acrylamide and 4‐vinyl pyridine, are efficiently dyed with an acid dye. Conversely, a fiber surface‐grafted with acidic functional monomer is easily dyed to deep shades with basic dyes. The dye adsorption increases monotonically with increasing grafting measured in ESCA spectra as relative intensities of relevant lines. The ungrafted HSPE, PP and PET fibers can be dyed to some extent with certain dyes. In the present work, the dye adsorption increased by 3.4 times for HSPE fiber grafted with GA and dyed with the metal complex dye IO, by 7.9 times for PP fiber grafted with AA and dyed with the basic dye MB, by 6.1 times for PET with AM and with the direct dye SL, and by about 15.3 times for PVA with VP and with the acid dye TE.

Preparation of a plasma polymer containing phosphine complexed nickel by concurrent nickel evaporation

AbstractThis article describes one of the first examples of concurrent metal evaporation and substituted hydrocarbon plasma polymerization as a general method for preparing thin films containing a metal coordinated to a plasma polymer. In this report, the evaporation of Ni into a triallylphosphine (TAP) glow discharge is described Deposition of a plasma polymer with concurrent reaction of Ni atoms with phosphine groups forms nickel containing triallylphosphine plasma polymer, NiTAPPP. The chemical nature of the product is derived on the basis of infrared spectra taken of the film as formed and after reaction with air, CO, and NO. The extent of the reaction is deduced from gravimetric data obtained during reaction with CO and with NO; each case was followed by evacuation of the gas. The CO gravimetric data also suggest that uncoordinated Ni is predominantly formed at high (Ni evaporation rate)/(plasma polymer deposition rate) ratios; coordinated Ni predominates at low values of this parameter. The ESCA spectra are also obtained for this plasma polymer (NiTAPPP) as well as for that described in the previous paper, in which TAP is plasma polymerized (yielding TAPPP) and subsequently reacted with Ni(CO)4 (TAPPP + Ni(CO)4). In both cases, it was found that Ni is oxidized on contact with air. After such air exposure, ESCA spectra reveal the presence of residual NiP moieties on the surface of TAPPP + Ni(CO)4, but not of NiTAPPP. This is attributed to the greater reactivity of the coordinatively unsaturated Ni sites postulated for NiTAPPP.