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Film Properties (film + property)
Selected AbstractsKinetics and Film Properties of Boron Nitride Derived from Trimethoxyborane/Ammonia by Chemical Vapor Deposition,CHEMICAL VAPOR DEPOSITION, Issue 6 2004H. Strakov Abstract The kinetics of the CVD of boron nitride from trimethoxyborane (TMOB) and ammonia (NH3) under atmospheric pressure was investigated by varying the following process parameters: temperature, residence time of the reactants, molar fraction of TMOB, and the NH3/TMOB ratio, ,. A kinetic power law equation was derived, that describes the experimental results with good accuracy. The reaction order with respect to TMOB is found to be 0.9 and ,,0.2 with respect to NH3. Between 800,°C and 950,°C, the deposition rate is controlled by the surface reaction kinetics with apparent activation energy of 115.1,kJ,mol,1. The deposited BN films were characterized by IR spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). The microstructure of the deposits depends on the nature of the substrates used. Turbostratic boron nitride (t-BN) was deposited on graphite, and hexagonal boron nitride (h-BN) on alumina substrates. X-ray photoelectron spectroscopy (XPS) analyses show nearly stoichiometric BN films for deposition temperatures in the range 850,950,°C for high amounts of ammonia (100,<,,,<,150) in the feed gas. [source] Growth of lead bromide polycrystalline filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2004M. Giles Abstract Lead bromide polycrystalline films were grown by the physical vapor deposition method (PVD). Glass 1,x1, in size, uncoated, and coated with Indium Tin Oxide (ITO), was used as substrate and rear contact. The starting material was evaporated at temperatures from 395°C to 530°C under high vacuum atmosphere (6 x 10 -3 Pa) and during 8 days. The substrate temperature was prefixed from 190°C to 220°C. Film thickness yielded values from 40 to 90 ,m. Optical microscopy and scanning electron microscopy (SEM) were performed on the films. Grain size resulted to be from 1.0 to 3.5 ,m. SEM and X-ray diffraction indicate that films grow with a preferred orientation with the (0 0 l) planes parallel to the substrate. The Texture Coefficient (TC) related to the plane (0 0 6) was 7.3. Resistivity values in the order of 1012 ,cm were obtained for the oriented samples, but a strong polarization indicates severe charge transport problems in the films. Film properties were correlated with the growth temperature and with previous results for films of other halides. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Low temperature growth of transparent conducting ZnO films by plasma assisted depositionPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2006A. Nishii Abstract Transparent conducting ZnO films are deposited by plasma assisted deposition technique on glass and plastic substrates at temperatures 60 , 300 °C using metallic Zn, metallic Ga and plasma-excited oxygen as source materials. Deposited films were characterized by X-ray diffraction (XRD), optical transmittance in the visible and infrared region, Raman scattering, and Hall measurements. Film properties are controlled by substrate temperature, oxygen source/zinc source supply ratio, and Ga doping. 350 nm-thick Ga-doped ZnO films deposited at 290 °C showed low resistivity (,2 × 10,4 , cm) and high transmittance in the visible region (,85%). (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effect of deposition temperature on the properties of thin polymer films deposited by plasma-enhanced CVD using cyclo-hexa-hydrocarbons as monomersELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 4 2010Kazunori Moriki Abstract Plasma CVD is a candidate technology for the fabrication of optical polymer waveguides. It can deposit a film on any surface geometry and any substrate material at a temperature under 200 °C in a vacuum process. It also provides good thickness controllability and uniformity of the deposition film. In the present study, the effects of the deposition temperature on film properties, specifically the refractive index, deposition rate, and molecular structure, are discussed. The refractive index decreases as the deposition temperature rises. The logarithm of the deposition rate increases with the reciprocal of the temperature and the gradient of the deposition rate depends on the relative abundance of double bonds in the monomer source. The gradient does not change when CF4 is used instead of Ar as the gas mixed into the plasma, although the deposition rate increases by a factor of about five. We speculate that the deposition rate increases due to the increase in the abundance precursors produced by the presence of CF4 in the plasma and due to an increased abundance of dangling bonds on the surface of the deposition film caused by F radicals. We further speculate that the precursors incorporated into the polymer are selected on the substrate by the density of adsorption sites and the adsorption energy. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(4): 27,35, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10171 [source] Relationship between Condition of Deposition and Properties of W-Ti-N Thin Films Prepared by Reactive Magnetron Sputtering,ADVANCED ENGINEERING MATERIALS, Issue 3 2006V. Kuchuk A correlation between the film properties of nitrides, oxides etc., and their structure, is of fundamental importance , not only for thin solid films physics but also for practical applications. The structure of the films depends on deposition methods and their parameters. The relationship between properties (chemical and phase compositions, surface morphology, and electrical resistivity) and nitrogen partial pressure of reactive magnetron sputtered W-Ti-N thin films has been discussed here in detail. [source] Electric Field-Directed Convective Assembly of Ellipsoidal Colloidal Particles to Create Optically and Mechanically Anisotropic Thin FilmsADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Manish Mittal Abstract A method of simultaneous field- and flow-directed assembly of anisotropic titania (TiO2) nanoparticle films from a colloidal suspension is presented. Titania particles are oriented by an alternating (ac) electric field as they simultaneously advect towards a drying front due to evaporation of the solvent. At high field frequencies (,,>,,25,kHz) and field strengths (E,>,300,V cm,1), the particles orient with their major axis along the field direction. As the front recedes, a uniform film with thicknesses of 1,10,µm is deposited on the substrate. The films exhibit a large birefringence (,n,,,0.15) and high packing fraction (,,=,0.75,±,0.08), due to the orientation of the particles. When the frequency is lowered, the particle orientation undergoes a parallel,random,perpendicular transition with respect to the field direction. The orientation dependence on field frequency and strength is explained by the polarizability of ellipsoidal particles using an interfacial polarization model. Particle orientation in the films also leads to anisotropic mechanical properties, which are manifested in their cracking patterns. In all, it is demonstrated that the field-directed assembly of anisotropic particles provides a powerful means for tailoring nanoparticle film properties in situ during the deposition process. [source] Multiple Functionalities of Polyelectrolyte Multilayer Films: New Biomedical ApplicationsADVANCED MATERIALS, Issue 4 2010Thomas Boudou Abstract The design of advanced functional materials with nanometer- and micrometer-scale control over their properties is of considerable interest for both fundamental and applied studies because of the many potential applications for these materials in the fields of biomedical materials, tissue engineering, and regenerative medicine. The layer-by-layer deposition technique introduced in the early 1990s by Decher, Moehwald, and Lvov is a versatile technique, which has attracted an increasing number of researchers in recent years due to its wide range of advantages for biomedical applications: ease of preparation under "mild" conditions compatible with physiological media, capability of incorporating bioactive molecules, extra-cellular matrix components and biopolymers in the films, tunable mechanical properties, and spatio-temporal control over film organization. The last few years have seen a significant increase in reports exploring the possibilities offered by diffusing molecules into films to control their internal structures or design "reservoirs," as well as control their mechanical properties. Such properties, associated with the chemical properties of films, are particularly important for designing biomedical devices that contain bioactive molecules. In this review, we highlight recent work on designing and controlling film properties at the nanometer and micrometer scales with a view to developing new biomaterial coatings, tissue engineered constructs that could mimic in vivo cellular microenvironments, and stem cell "niches." [source] Silicon carbonitride thin-film coatings fabricated by remote hydrogen,nitrogen microwave plasma chemical vapor deposition from a single-source precursor: Growth process, structure, and properties of the coatings,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007A. M. Wrobel Abstract Silicon carbonitride (Si:C:N) films were produced by remote hydrogen,nitrogen microwave plasma chemical vapor deposition (RP-CVD) from a 1,1,3,3-tetramethyldisilazane precursor with a nitrogen content {[N2]/([H2] + [N2])} of 0.88 in the plasma-generating mixture and a substrate temperature in the range of 30,400°C. The effects of the substrate temperature on the rate and yield of the RP-CVD process and chemical structure (examined by Fourier transform infrared spectroscopy) of the resulting films were investigated. The Si:C:N film properties were characterized in terms of the density, hardness, elastic modulus, and friction coefficient. With the IR structural data, reasonable structure,property relationships were determined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 122,129, 2007 [source] Contribution of the Starch, Protein, and Lipid Fractions to the Physical, Thermal, and Structural Properties of Amaranth (Amaranthus caudatus) Flour FilmsJOURNAL OF FOOD SCIENCE, Issue 5 2007D. Tapia-Blácido ABSTRACT:, Amaranth protein,lipid (PL) and protein (P) films were elaborated and compared with amaranth flour films in order to determine the contribution of the interactions between the biopolymer (starch and protein) and the lipids to the film properties. The films were made by the casting method, using the same glycerol concentration (0.9 g glycerol/100 g solution). A separation of the lipid fraction in the PL films and a polymorphic transformation of the corresponding fatty acids were observed by differential scanning calorimetry (DSC) and verified by an analysis of the microstructure by scanning electron microscopy (SEM). The flour films showed no separation of the lipid fraction, evidence that the lipids were strongly associated with the proteins and homogenously distributed throughout the starch network, contributing to the good mechanical properties when compared to the PL films and to the excellent barrier properties when compared to both the PL and P films. The protein-protein interactions also contributed to the mechanical properties of the flour films. The presence of proteins and lipids in the flour films had an important effect on film solubility, and also on the color and opacity of the films. This study showed that the flour film properties depended on the interactions formed by their polymers (starches and proteins) and by the lipid, on the distribution of these interactions within the film matrix and on the concentrations of each component in the film. [source] Functional Properties of Antimicrobial Lysozyme-Chitosan Composite FilmsJOURNAL OF FOOD SCIENCE, Issue 8 2004S.-I. Park ABSTRACT: Lysozyme-chitosan composite films were developed for enhancing the antimicrobial properties of chitosan films. A 10% lysozyme solution was incorporated into 2% chitosan film-forming solution (FFS) at a ratio of 0%, 20%, 60%, and 100% (w lysozyme/w chitosan). Films were prepared by solvent evaporation. Lysozyme release from the film matrix, the antimicrobial activity of films against Escherichia coli and Streptococcus faecalis, and basic film properties were investigated. The lysozyme release proportionally increased with increasing initial concentration of lysozyme in the film matrix, and the amount of released lysozyme was in natural log relationship with time. The films with 60% lysozyme incorporation enhanced the inhibition efficacy of chitosan films against both S. faecalis and E. coli, where 3.8 log cycles reduction in S. faecalis and 2.7 log cycles reduction in E. coli were achieved. Water vapor permeability of the chitosan films was not affected by lysozyme incorporation, whereas the tensile strength and percent elongation values decreased with increased lysozyme concentration. Scanning electron microscopy images revealed that lysozyme was homogeneously distributed throughout the film matrix. This study demonstrated that enhanced antimicrobial activity of lysozyme-chitosan composite films can be achieved by incorporating lysozyme into chitosan, thus broadening their applications in ensuring food quality and safety. [source] Photopolymerization of ternary thiol,ene/acrylate systems: Film and network propertiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2007Huanyu Wei Abstract Photocurable, ternary-component mixtures of a 1:1 molar multifunctional thiol,ene (trithiol and triallyl ether) blend and a 16-functional acrylate based monomer have been photopolymerized, and the final film properties of the ternary crosslinked networks have been measured. The photopolymerization kinetics, morphology, and mechanical and physical properties of the films have been investigated with real-time infrared, atomic force microscopy, and dynamic mechanical analysis. The photopolymerization process is a combination of acrylate homopolymerization and copolymerizations of thiol with allyl ether and acrylate functionalities. The tan , peaks of the photopolymerized ternary systems are relatively narrow and tunable over a large temperature range. The morphology is characterized by a distinct phase-separated nanostructure. The photocured thiol,ene/acrylate ternary systems can be made to exhibit good mechanical properties with enhanced energy absorption at room temperature by the appropriate selection of each component concentration. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 822,829, 2007. [source] Water-Based Coatings Based on Mixtures of Acrylic Dispersions and Alkyd EmulsionsMACROMOLECULAR SYMPOSIA, Issue 1 2009Patrick J. J. Kivit Abstract In this work acrylic dispersions were mixed with alkyd emulsions to obtain coatings that lower the amount of volatile organic compounds (VOC) in surface coatings. The advantage of this approach is that the fast drying of the acrylic is combined with the good film properties of the alkyd. Films produced with an alkyd and a soft acrylic (AA1) did not exhibit good film properties. Whereas, films produced with a hard acrylic (SA1 and AA2) and a soft alkyd gave films with good appearance, appropriate drying times, superior pendulum hardness and promising values of gloss. VOC was calculated below 25,g/L. The novel mixtures may be applied as high gloss enamels for architectural coatings. [source] Effect of pre-treatment with carbon monoxide and film properties on the quality of vacuum packaging of beef chopsPACKAGING TECHNOLOGY AND SCIENCE, Issue 7 2008Estrella Aspé Abstract Beef chops (longissimus dorsi) were pre-treated with 5% carbon monoxide (CO) , 95% N2 for 24,h, vacuum packed in thermo-contractile bags and stored at 0 ± 2°C. Shelf life, as determined by the viable aerobic bacterial load, was 11 weeks. Vacuum-packed chops with heat-contractile film produced a smaller drip loss, had a more intense red colour and higher colour stability under storage than chops with non-heat-contractile film. Chops pre-treated with CO were redder during all the storage period than controls without CO. The pre-treatment did not affect pH, water-holding capacity, drip loss or rancidity of the meat stored in vacuum. Copyright © 2008 John Wiley & Sons, Ltd. [source] Ionized physical vapor deposited Al2O3 films: Does subplantation favor formation of ,-Al2O3?PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 7 2010K. Sarakinos Abstract The broad energy distributions of the condensing particles typically encountered in ion assisted vapor deposition techniques are often a drawback when attempting to understand the effect of the energetic bombardment on the film properties. In the current study, a monoenergetic Al+ beam generated by a filtered cathodic arc discharge is employed for the deposition of alumina (Al2O3) films at well defined Al+ ion energies between 4 eV and 200 eV at a substrate temperature of 720 °C. Structural analysis shows that Al+ energies of 40 eV or larger favor the formation of the thermodynamically stable ,-Al2O3 phase at the expense of other metastable Al2O3 polymorphs. The well defined ion energies are used as input for Monte-Carlo based simulations of the ion,surface interactions. The results of these simulations reveal that the increase of the Al+ ion energy leads to an increase in the fraction of ions subplanted into the growing film. These findings underline the previously not considered role of subsurface processes on the phase formation of ionized physical vapor deposited Al2O3 films. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effects of water vapor introduction during Cu(In1,xGax)Se2 deposition on thin film properties and solar cell performancePHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2006S. Ishizuka Abstract The effects of water vapor introduction during the growth of Cu(In1,xGax)Se2, specifically CuInSe2 (CISe), Cu(In,Ga)Se2 (CIGSe), and CuGaSe2 (CGSe) thin films were studied. We have developed thus far a novel technique to improve CIGSe (x , 0.5) cell performance by means of water vapor introduction during CIGSe deposition. In this study, we have examined the effectiveness of water vapor introduction for other x -compositions (CISe and CGSe). Variations in the electrical properties observed in CIGSe (x , 0.5), that is, increasing hole density and conductivity with water vapor introduction, were also observed in CISe and CGSe. Water vapor introduction affected solar cell performance as well; open circuit voltages, short circuit current densities, and efficiencies were improved. The improvements in cell performance are thought to be related to annihilation of donor defects arising from Se-vacancies by incorporation of oxygen from the water vapor. In addition to this, the sodium content in the CIGSe layers was found to depend on the partial pressure of water vapor during deposition. This result suggests that the improvement mechanism is also related with the so-called ,Na-effects'. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Gas Phase Modification of Superhard Carbon Coatings Deposited by Pulsed DC-Arc-ProcessPLASMA PROCESSES AND POLYMERS, Issue S1 2009Werner Grimm Abstract The pulsed vacuum arc discharge (pulsed arc) is the most efficient PVD technology for deposition of hard amorphous carbon coatings on tools and machinery parts. Due to the pulsed arc discharge a stable evaporation process and the efficient deposition of hydrogen-free a-C type coatings is possible. This paper shows that the pulsed arc enables the deposition of ta-C and modified a-C coatings with interesting coating properties in a wide pressure range of argon, acetylene and ammonia gas atmosphere. Coatings with different gas flow rates of these gases were deposited on steel substrates. The coating properties were characterized by using different analytical methods for determination of structure, hardness, friction and wear behaviour. The changes of film properties in dependence of the kind and the rate of gas flow are compared and discussed. [source] Atmospheric Pressure Barrier Discharge Deposition of Silica-Like Films on Polymeric SubstratesPLASMA PROCESSES AND POLYMERS, Issue S1 2007Sergei Starostine Abstract Silica-like coatings were deposited on polymer foils in APG discharge in a roll-to-roll configuration. The dependence of film structure and chemical composition on the conditions during deposition process was studied by means of SEM, ATR-FTIR, and XPS analysis. The influence of oxidant concentration on the deposited film properties is analyzed and discussed. It was observed that pulsing of the APG discharge suppresses dust formation in atmospheric plasma and, therefore, provides uniform coatings. [source] Comparison of properties of acrylic,polyurethane hybrid emulsions prepared by batch and semibatch processes with monomer emulsion feedPOLYMER INTERNATIONAL, Issue 5 2003ebenik Abstract Aqueous acrylic,polyurethane hybrid emulsions were prepared by batch and semibatch polymerization of acrylic monomer mixtures (butyl acrylate, methyl methacrylate and acrylic acid) in the presence of polyurethane dispersion. The acrylic component was introduced in the monomer emulsion feed. The weight ratio between acrylic and polyurethane components was varied to obtain different emulsion properties, microphase structure and mechanical film properties. Scanning electron microscopy, average particle size and molecular weight measurements were performed to characterize the latex systems. Mechanical properties were examined by measuring Koenig hardnesses of dried films. The average particle size increased with the acrylic/polyurethane ratio. Particles of larger than average size and, to some extent, higher than average molecular weights by batch process were formed. Koenig hardnesses decreased with increasing acrylic/polyurethane ratio. Properties of emulsions synthesized by semibatch processes were compared with the results reported for a different polyurethane dispersion. Copyright © 2003 Society of Chemical Industry [source] Properties of uniaxially stretched polypropylene filmsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2008Farhad Sadeghi Abstract Polypropylene (PP) films have been prepared through two different cast extrusion processes: one using a machine direction orientation (MDO) unit and the other stretching the films at the die under high cooling conditions (lab unit). Films for two PP resins different in molecular structure have been prepared using both processing techniques. The effect of the resin structure and the processing conditions on the film properties has been examined. It was found that the MDO unit generated a highly oriented fibrillar crystalline structure with a distribution of elongated thick fibrils while extrusion under high cooling conditions generated an oriented row nucleated lamellar structure. The films showed distinctive tensile responses in stretching, with a strong solid-elastic response for the oriented MDO films and a steady strain hardening after yielding for the sample obtained from lab unit cast extrusion. It was found that the strength in the transverse direction (TD) was particularly very low for the oriented MDO films made of the bimodal PP. The oxygen permeability was reduced with increasing draw ratio (DR) for the MDO films. The haze property for the MDO samples reduced to a plateau for DR up to 5 while clarity improved continuously with DR. Des films de polypropylène ont été préparés dans deux procédés d'extrusion différents: l'un utilise une unité MDO (orientation dans la direction de la machine) et l'autre l'étirement des films à la filière dans des conditions de refroidissement intense (unité de laboratoire). Des films de polypropylène (PP) venant de deux résines de structure moléculaire différente ont été préparés à l'aide de ces deux techniques de mise en forme. L'effet de la structure de la résine et des conditions de mise en ,uvre sur les propriétés des films a été examiné. On a trouvé que l'unité MDO donne une structure cristalline fibrillaire hautement orientée avec une distribution de fibrilles épaisses allongées, tandis que l'extrusion sous refroidissement intense donne une structure lamellaire nucléée orientée en rangée. Les films montrent des réponses en contraintes à l'étirement distinctes, avec une forte réponse élastique solide pour les films MDO orientés et un écrouissage stable après déformation irréversible pour l'échantillon obtenu par extrusion avec l'unité de laboratoire. On a trouvé que la tenacité dans la direction transverse était particulièrement faible pour les films MDO orientés faits de PP bimodal. La perméabilité à l'oxygène a été réduite avec l'augmentation du rapport d'étirage pour les films MDO. La propriété de perte de transparence légère pour les échantillons MDO montre un plateau pour un rapport d'étirage allant jusqu'à 5 tandis que la clarté s'améliore continuellement avec le rapport d'étirage. [source] Characterization of microcrystalline Si films deposited at low temperatures with high rates by atmospheric-pressure plasma CVDPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010K. Ouchi Abstract Low-temperature and high-rate depositions of hydrogenated microcrystalline silicon (,c -Si:H) films are investigated using stable plasma excited at atmospheric pressure (AP) by supplying 150-MHz very high-frequency (VHF) power. VHF power density, H2/SiH4 ratio and plasma gap are varied as parameters under a fixed substrate temperature (Tsub) of 220 ,C. Increasing VHF power density and H2/SiH4 ratio is primarily important for the sufficient decomposition of source gas molecules, improving both deposition rate and film property. In addition, the plasma gap is found to be another crucial parameter in the deposition process using AP-VHF plasma. Numerical analyses on the temperature distribution around the plasma region have revealed that the steady-state surface temperature of the glass substrate becomes approximately 100 ,C higher than the back surface temperature (Tsub), which is caused by the moderate surface heating effect of the AP-VHF plasma. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||||||||||||||||||||