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Sample records for surface water films

  1. Thin Water and Ice Films at Mineral Surfaces

    Science.gov (United States)

    Yeşilbaş, Merve; Boily, Jean-François

    2016-04-01

    Mineral-water and ice interactions play important roles in atmospheric cloud formation. They also affect soil biogeochemistry as well as outer-space processes. In this study, thin water and ice films formed on minerals of varied bulk and surface structure, shape, size and surface roughness were probed by Fourier Transform Infrared Spectroscopy (FTIR) and by Dynamic Vapor Adsorption (DVA). Measurements on several types of iron (oxyhydr)oxides, phyllosilicates, orthosilicates, tectosilicates as well as Arizona Test Dust (ATD) and Icelandic volcanic ash constrained our understanding of the molecular-level nature of mineral surface-water and ice interactions. DVA experiments showed that particle size is the key feature controlling water loadings at 25 ° C. Under this condition, nano-sized particles stabilized the equivalence of no more than ˜6 monolayers of water at the near saturation of water vapor while sub-micron sized particles stabilized several thousand layers. This result can be explained by the greater ability of larger sized particles at driving water condensation reactions. Cryogenic FTIR measurements at -10 and -50 ° C revealed that most minerals acquired the thin ice films with similar hydrogen bonding environments as those formed at room temperature.[1,2] These thin ice films have weaker hydrogen bond environments than hexagonal ice (νOH ≈ 3130 cm-1), a result seen by FTIR through predominant O-H stretching modes at νOH ≈ 3408-3425 cm-1. The water bending region (˜1630 cm-1) also reveals that most thin ice films are rather supercooled forms of water. Only the materials with greatest levels of heterogeneity, namely ATD and volcanic ash, stabilized solid forms of water reminiscent to hexagonal ice. This work thus constrains further our understanding of how interfacial ice is stabilized at mineral surfaces, and opens possibilities for future studies focused on atmospheric gas uptake on mineral- water and ice admixtures. [1] Song, X. and Boily, J

  2. Fabrication of ZnO submicrorod films with water repellency by surface etching and hydrophobic modification

    Energy Technology Data Exchange (ETDEWEB)

    Hou Xianming, E-mail: xmhou@tsu.edu.cn [Department of Chemistry and Environmental Science, Taishan University, Taian 271021 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang Lixia [Department of Chemistry and Environmental Science, Taishan University, Taian 271021 (China); Zhou Feng [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li Liqing [Department of Chemistry and Environmental Science, Taishan University, Taian 271021 (China)

    2011-09-01

    Superhydrophobic ZnO submicrorod films have been fabricated on zinc sheets through an H{sub 2}O{sub 2}-assisted surface etching process and subsequent surface modification with a monolayer of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FDS). The crystal structure, chemical compositions, morphologies, and wettability of the resultant ZnO films were analyzed by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle measurements. It is found that the surface of the as-prepared ZnO films on zinc substrate was hydrophobic with a water contact angle of 95 {+-} 2 deg., whereas after modification with FDS, the film exhibited superhydrophobicity and the water CA increased to 154 {+-} 2 deg. It is shown that both the higher surface roughness and the lower surface free energy play an important role in creating the superhydrophobic films.

  3. Nanoscale cellulose films with different crystallinities and mesostructures--their surface properties and interaction with water.

    Science.gov (United States)

    Aulin, Christian; Ahola, Susanna; Josefsson, Peter; Nishino, Takashi; Hirose, Yasuo; Osterberg, Monika; Wågberg, Lars

    2009-07-07

    A systematic study of the degree of molecular ordering and swelling of different nanocellulose model films has been conducted. Crystalline cellulose II surfaces were prepared by spin-coating of the precursor cellulose solutions onto oxidized silicon wafers before regeneration in water or by using the Langmuir-Schaefer (LS) technique. Amorphous cellulose films were also prepared by spin-coating of a precursor cellulose solution onto oxidized silicon wafers. Crystalline cellulose I surfaces were prepared by spin-coating wafers with aqueous suspensions of sulfate-stabilized cellulose I nanocrystals and low-charged microfibrillated cellulose (LC-MFC). In addition, a dispersion of high-charged MFC was used for the buildup of polyelectrolyte multilayers with polyetheyleneimine on silica with the aid of the layer-by-layer (LbL) technique. These preparation methods produced smooth thin films on the nanometer scale suitable for X-ray diffraction and swelling measurements. The surface morphology and thickness of the cellulose films were characterized in detail by atomic force microscopy (AFM) and ellipsometry measurements, respectively. To determine the surface energy of the cellulose surfaces, that is, their ability to engage in different interactions with different materials, they were characterized through contact angle measurements against water, glycerol, and methylene iodide. Small incidence angle X-ray diffraction revealed that the nanocrystal and MFC films exhibited a cellulose I crystal structure and that the films prepared from N-methylmorpholine-N-oxide (NMMO), LiCl/DMAc solutions, using the LS technique, possessed a cellulose II structure. The degree of crystalline ordering was highest in the nanocrystal films (approximately 87%), whereas the MFC, NMMO, and LS films exhibited a degree of crystallinity of about 60%. The N,N-dimethylacetamide (DMAc)/LiCl film possessed very low crystalline ordering (properties of the films, it was necessary to consider both the

  4. Thickness and structure of the water film deposited from vapour on calcite surfaces

    DEFF Research Database (Denmark)

    Bohr, Jakob; Wogelius, Roy A.; Morris, Peter M.

    2010-01-01

    Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from......Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from...

  5. Measurements of water film characteristics on airfol surfaces from wind-tunnel tests with simulated heavy rain

    Science.gov (United States)

    Hastings, E. C., Jr.; Manuel, G. S.

    1985-01-01

    This paper discusses some of the surface water characteristics obtained during recent simulated heavy rain experiments conducted at the Langley Research Center. Water film distributions and discrete film thickness measurements on several model wings are discussed. The water film distributions on the upper surfaces are shown in photographs from cameras mounted above the models, and film thickness data are presented which were obtained using resistance sensors mounted flush with the upper and lower wing model surfaces. The paper also discusses potential sources of performance decrements indicated by the data.

  6. Spreading of oil films on water in the surface tension regime

    Energy Technology Data Exchange (ETDEWEB)

    Camp, D.W.

    1985-01-01

    Surface tension forces will cause an oil to spread over water if the tension of the oil film (the summed surface and interfacial tensions for bulk oil films, or the equilibrium spreading tension for monomolecular films) is less than the surface tension of water. For oil films spreading in a 40 cm long channel, measurements are made of leading edge position and lateral profiles of film thickness, velocity, and tension as a function of time. Measurements of the tension profiles, important for evaluating proposed theories, is made possible by the development of a new technique based on the Wilhelmy method. The oils studied were silicones, fatty acids and alcohols, and mixtures of surfactants in otherwise nonspreading oils. The single-component oils show an acceleration zone connecting a slow-moving inner region with a fast-moving leading monolayer. The dependence of film tension on film thickness for spreading single-component oils often differs from that at equilibrium. The mixtures show a bulk oil film configuration which extends to the leading edge and have velocity profiles which increase smoothly. The theoretical framework, similarity transformation, and asymptotic solutions of Foda and Cox for single-component oils were shown to be valid. An analysis of spreading surfactant-oil mixtures is developed which allows them to be treated under this framework. An easily-used semi-empirical model is proposed which allows them to be treated under this framework. An easily-used semi-empirical model is proposed which allows accurate prediction of detailed spreading behavior for any spreading oil.

  7. Modeling the interaction Between Ethylene Diamine and Water Films on the Surface of a Carbon Nanotube

    Science.gov (United States)

    Jaffe, Richard L.; Walther, Jens H.; Zimmerli, Urs; Koumoutsakos, Petros

    2004-01-01

    It has been observed that a carbon nanotube (CNT) AFM tip coated with ethylene diamine (EDA) penetrates the liquid water-air interface more easily than an uncoated nanotube tip. The EDA coating remains intact through repeated cycles of dipping and removal. In order to understand the physical basis for this observation, we use ab initio quantum chemistry calculations to study the EDA-CNT-water interaction and to parameterize a force field describing this system. Molecular dynamics (MD) simulations are carried out for EDA-water mixtures and an EDA-coated carbon nanotube immmed in water. These simulations are similar to our earlier MD study that characterized the CNT-water interface. The attractive CNT-EDA and CNT-water interactions arise primarily from van der Waals forces, and the EDA-EDA, EDA-water and water-water interactions are mainly due to hydrogen bond formation. The binding energ of single EDA molecule to the nanotube is nearly three times larger than the corresponding value found for water (4.3 versus 1.5 kcal mol, respectively). The EDA molecules readily stick to and diffuse along the CNT surface. As a resulf mixing of the EDA and water films does not occur on the timescale of the MD simulations. The EDA film reduces the hydrophobicity of the nanotube surface and acts like a prototypical surfactant in stabilizing the suspension of carbon nanotubes in water. For this presentation, we use the MD simulations to determine how the presence of the carbon nanotube surface perturbs the properties of EDA-water mixtures.

  8. The influence of the surface composition of mixed monolayer films on the evaporation coefficient of water.

    Science.gov (United States)

    Miles, Rachael E H; Davies, James F; Reid, Jonathan P

    2016-07-20

    We explore the dependence of the evaporation coefficient of water from aqueous droplets on the composition of a surface film, considering in particular the influence of monolayer mixed component films on the evaporative mass flux. Measurements with binary component films formed from long chain alcohols, specifically tridecanol (C13H27OH) and pentadecanol (C15H31OH), and tetradecanol (C14H29OH) and hexadecanol (C16H33OH), show that the evaporation coefficient is dependent on the mole fractions of the two components forming the monolayer film. Immediately at the point of film formation and commensurate reduction in droplet evaporation rate, the evaporation coefficient is equal to a mole fraction weighted average of the evaporation coefficients through the equivalent single component films. As a droplet continues to diminish in surface area with continued loss of water, the more-soluble, shorter alkyl chain component preferentially partitions into the droplet bulk with the evaporation coefficient tending towards that through a single component film formed simply from the less-soluble, longer chain alcohol. We also show that the addition of a long chain alcohol to an aqueous-sucrose droplet can facilitate control over the degree of dehydration achieved during evaporation. After undergoing rapid gas-phase diffusion limited water evaporation, binary aqueous-sucrose droplets show a continued slow evaporative flux that is limited by slow diffusional mass transport within the particle bulk due to the rapidly increasing particle viscosity and strong concentration gradients that are established. The addition of a long chain alcohol to the droplet is shown to slow the initial rate of water loss, leading to a droplet composition that remains more homogeneous for a longer period of time. When the sucrose concentration has achieved a sufficiently high value, and the diffusion constant of water has decreased accordingly so that bulk phase diffusion arrest occurs in the monolayer

  9. Micropatterned Surfaces for Atmospheric Water Condensation via Controlled Radical Polymerization and Thin Film Dewetting.

    Science.gov (United States)

    Wong, Ian; Teo, Guo Hui; Neto, Chiara; Thickett, Stuart C

    2015-09-30

    Inspired by an example found in nature, the design of patterned surfaces with chemical and topographical contrast for the collection of water from the atmosphere has been of intense interest in recent years. Herein we report the synthesis of such materials via a combination of macromolecular design and polymer thin film dewetting to yield surfaces consisting of raised hydrophilic bumps on a hydrophobic background. RAFT polymerization was used to synthesize poly(2-hydroxypropyl methacrylate) (PHPMA) of targeted molecular weight and low dispersity; spin-coating of PHPMA onto polystyrene films produced stable polymer bilayers under appropriate conditions. Thermal annealing of these bilayers above the glass transition temperature of the PHPMA layer led to complete dewetting of the top layer and the formation of isolated PHPMA domains atop the PS film. Due to the vastly different rates of water nucleation on the two phases, preferential dropwise nucleation of water occurred on the PHPMA domains, as demonstrated by optical microscopy. The simplicity of the preparation method and ability to target polymers of specific molecular weight demonstrate the value of these materials with respect to large-scale water collection devices or other materials science applications where patterning is required.

  10. Pulsed erbium laser ablation of hard dental tissue: the effects of atomized water spray versus water surface film

    Science.gov (United States)

    Freiberg, Robert J.; Cozean, Colette D.

    2002-06-01

    It has been established that the ability of erbium lasers to ablate hard dental tissue is due primarily to the laser- initiated subsurface expansion of the interstitial water trapped within the enamel and that by maintaining a thin film of water on the surface of the tooth, the efficiency of the laser ablation is enhanced. It has recently been suggested that a more aggressive ablative mechanism, designated as a hydrokinetic effect, occurs when atomized water droplets, introduced between the erbium laser and the surface of the tooth, are accelerated in the laser's field and impact the tooth's surface. It is the objective of this study to determine if the proposed hydrokinetic effect exists and to establish its contribution to the dental hard tissue ablation process. Two commercially available dental laser systems were employed in the hard tissue ablation studies. One system employed a water irrigation system in which the water was applied directly to the tooth, forming a thin film of water on the tooth's surface. The other system employed pressurized air and water to create an atomized mist of water droplets between the laser hand piece and the tooth. The ablative properties of the two lasers were studied upon hard inorganic materials, which were void of any water content, as well as dental enamel, which contained interstitial water within its crystalline structure. In each case the erbium laser beam was moved across the surface of the target material at a constant velocity. When exposing material void of any water content, no ablation of the surfaces was observed with either laser system. In contrast, when the irrigated dental enamel was exposed to the laser radiation, a linear groove was formed in the enamel surface. The volume of ablated dental tissue associated with each irrigation method was measured and plotted as a function of the energy within the laser pulse. Both dental laser systems exhibited similar enamel ablation rates and comparable ablated surface

  11. Surface and bulk crystallization of amorphous solid water films: Confirmation of "top-down" crystallization

    Science.gov (United States)

    Yuan, Chunqing; Smith, R. Scott; Kay, Bruce D.

    2016-10-01

    The crystallization kinetics of nanoscale amorphous solid water (ASW) films are investigated using temperature-programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS). TPD measurements are used to probe surface crystallization and RAIRS measurements are used to probe bulk crystallization. Isothermal TPD results show that surface crystallization is independent of the film thickness (from 100 to 1000 ML). Conversely, the RAIRS measurements show that the bulk crystallization time increases linearly with increasing film thickness. These results suggest that nucleation and crystallization begin at the ASW/vacuum interface and then the crystallization growth front propagates linearly into the bulk. This mechanism was confirmed by selective placement of an isotopic layer (5% D2O in H2O) at various positions in an ASW (H2O) film. In this case, the closer the isotopic layer was to the vacuum interface, the earlier the isotopic layer crystallized. These experiments provide direct evidence to confirm that ASW crystallization in vacuum proceeds by a "top-down" crystallization mechanism.

  12. Surface and bulk crystallization of amorphous solid water films: Confirmation of “top-down” crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Chunqing; Smith, R. Scott; Kay, Bruce D.

    2016-10-01

    The crystallization kinetics of nanoscale amorphous solid water (ASW) films are investigated using temperature-programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS). TPD measurements are used to probe surface crystallization and RAIRS measurements are used to probe bulk crystallization. Isothermal TPD results show that surface crystallization is independent of the film thickness (from 100 to 1000 ML). Conversely, the RAIRS measurements show that the bulk crystallization time increases linearly with increasing film thickness. These results suggest that nucleation and crystallization begin at the ASW/vacuum interface and then the crystallization growth front propagates linearly into the bulk. This mechanism was confirmed by selective placement of an isotopic layer (5% D2O in H2O) at various positions in an ASW (H2O) film. In this case, the closer the isotopic layer was to the vacuum interface, the earlier the isotopic layer crystallized. These experiments provide direct evidence to confirm that ASW crystallization in vacuum proceeds by a “top-down” crystallization mechanism.

  13. Hidden force stiffening molecular clusters, surface skins, and ultrathin films of water

    CERN Document Server

    Sun, Chang Q

    2013-01-01

    A slight, molecular-undercoordination-induced contraction of the stiffer O-H real-bond and a significant, inter-electron-pair repulsion driven, elongation of the softer H:O non-bond, and the associated stiffness relaxation, of the segmented O-H:O bond, are recognized as the key to stiffening molecular clusters, surface skins, and ultrathin films of water. Agreement between calculations and measurements verified our expectations that the shortened-and-stiffened real-bond stiffens the stiffer phonons (>3000 cm-1), densifies bonding electrons, entraps binding energy, and elevates the melting point and hence the viscosity, surface tension, and elasticity, and that the lengthened-and-softened non-bond softens the softer phonons (<300 cm-1), expands the volume, and polarizes the electron pairs of the undercoordinated molecules in freestanding and encapsuled clusters, water surfaces, and ultrathin films that exhibit ice- or glue-like and hydrophobic nature at the ambient. This effect becomes more significant as N...

  14. Water effect on the surface morphology of TiO2 thin film modified by polyethylene glycol

    Science.gov (United States)

    Wang, Sheng-Hung; Wang, Kuo-Hua; Dai, Yong-Ming; Jehng, Jih-Mirn

    2013-01-01

    Water effect on the surface morphology of TiO2 thin film was investigated by using PEG-6000 as a template to form the porous structure. The porous TiO2 thin films were characterized by thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), n&k Analyzer, UV-vis spectrophotometer, field-emission scanning electron microscopy (FE-SEM), and atomic forced microscopy (AFM) as a function of water content in the preparation of TiO2 thin film. The various water contents result in the TiO2 thin films possessing different surface structures, grain sizes, and thicknesses. The grain sizes were varied with changing the water content, and the thickness increased with increasing water content due to the enhancement of the cross-linking speed. In addition, the cratered surface structure transformed into cracked surface structure upon the water content beyond stoichiometric quantity because the excess water causes the aggregation of polyethylene glycol (PEG-6000). The photocatalysis has been performed by the degradation of methyl blue with corresponding structural characteristics of the TiO2 thin film. The best photocatalytic activity has been obtained when the ratio of water to titanium precursor is equal to 2 referred as TiO2-W2.

  15. Nickel Alloy Primary Water Bulk Surface and SCC Corrosion Film Analytical Characterization and SCC Mechanistic Implications

    Energy Technology Data Exchange (ETDEWEB)

    Morton, D.; Lewis, N.; Hanson, M.; Rice, S.; Sanders, P.

    2007-04-18

    Alloy 600 corrosion coupon tests were performed: (1) to quantify the temperature dependency of general corrosion and (2) to characterize the composition and structure of bulk surface corrosion films for comparison with ongoing primary water SCC (PWSCC) crack tip corrosion film analyses. Results suggest that the thermal activation energy of Alloy 600 corrosion is consistent with the thermal activation energy of nickel alloy PWSCC. Analytical investigations of the structure and composition of Alloy 600 bulk surface corrosion oxides revealed a duplex (inner and outer) oxide layer structure. The outer layer is discontinuous and comprised of relatively large (1 to 3 {micro}m) nickel ferrite crystals and smaller ({approx}0.1 {micro}m) chromium containing nickel ferrite crystals. The inner layer consists of a relatively continuous chromite spinel (major phase) and chromia (Cr{sub 2}O{sub 3} minor phase) which formed through non-selective oxidation. Chromia and dealloyed Alloy 600 (highly Ni enriched metal) were only observed at 337 C (640 F) and only along the boundaries of deformation induced fine grains and subcells. Specimens having deformation free surfaces exhibited continuous uniform inner chromite spinel oxide layers. Specimens with machining induced surface deformation produced non-uniform inner layer oxides (chromite spinel, Cr{sub 2}O{sub 3} and unoxidized material). PWSCC crack tip oxides, in contrast, were fine grain (no duplex structure) and consisted of both chromium rich spinels and ''NiO'' structure oxides. Generally, nickel rich oxides were more abundant under more oxidized conditions (reduced coolant hydrogen) and spinel rich crack tip oxides were favored under more reducing conditions (increased coolant hydrogen). Bulk surface corrosion film thickness did not correlate with observed SCC growth rates. These results suggest that corrosion is not the rate controlling step of PWSCC but rather that PWSCC and corrosion have a common rate

  16. Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water

    Directory of Open Access Journals (Sweden)

    Ruifeng Zhang

    2017-07-01

    Full Text Available An iron-manganese co-oxide filter film (MeOx has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeOx was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeOx was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6–8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeOx included both biological (accounted for about 41.05% and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%. The investigation of the characterizations suggested that MeOx was formed by abiotic ways and the main elements on the surface of MeOx were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeOx as both ammonia molecules and ammonium ions and the active species of O2 were possibly •O and O2−.

  17. Interaction of indium oxide nanoparticle film surfaces with ozone, oxygen and water

    Energy Technology Data Exchange (ETDEWEB)

    Himmerlich, M.; Eisenhardt, A.; Berthold, T.; Krischok, S. [Institut fuer Physik and Institut fuer Mikro- und Nanotechnologien MacroNano, Technische Universitaet Ilmenau, PF 100565, 98684 Ilmenau (Germany); Wang, C.Y.; Cimalla, V.; Ambacher, O. [Fraunhofer-Institut fuer Angewandte Festkoerperphysik, Tullastrasse 72, 79108 Freiburg (Germany)

    2016-03-15

    The interaction of defect-rich nanocrystalline indium oxide films, which have previously shown to exhibit excellent ozone sensing properties, with O{sub 3}, O{sub 2}, and H{sub 2}O molecules is investigated using ultra-violet and X-ray photoelectron spectroscopy. The investigated samples are grown by metalorganic chemical vapor deposition at low temperatures resulting in high oxygen deficiency and high defect density. The ozone-induced surface oxidation and UV-induced photoreduction mechanisms of the ozone sensor active material are evaluated with respect to surface stoichiometry and electronic properties including adsorbate features, band bending and surface dipole formation. A strong interaction with ozone and water is found, whereas the interaction with O{sub 2} is relatively weak. In all cases the interaction results in the same negatively charged oxygen adsorbate species, which can either be removed by UV light or by annealing resulting in the capability of these films to be used in reversible adsorption induced oxidation and UV/thermal reduction cycles. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Thickness dependence of surface energy and contact angle of water droplets on ultrathin MoS2 films.

    Science.gov (United States)

    Guo, Yanhua; Wang, Zhengfei; Zhang, Lizhi; Shen, Xiaodong; Liu, Feng

    2016-06-01

    We have performed a systematic density functional study of surface energy of MoS2 films as a function of thickness from one to twelve layers with the consideration of van der Waals (vdW) interactions using the vdW-DF and DFT-D2 methods. Both vdW schemes show that the surface energy will increase with the increase of the number of atomic layers and converge to a constant value at about six layers. Based on the calculated surface energies, we further analyze the surface contact angle of water droplets on the MoS2 film surface using Young's equation as a function of thickness in comparison with experiments, from which the water-MoS2 interfacial energy is derived to be independent of MoS2 thickness. Our calculations indicate that the vdW interactions between the MoS2 layers play an important role in determining surface energy, and results in the thickness dependence of the contact angle of water droplets on the MoS2 film surface. Our results explain well the recent wetting experiment [Nano Lett., 2014, 14(8), 4314], and will be useful for future studies of physical and chemical properties of ultrathin MoS2 films.

  19. Dynamic wetting and de-wetting of thin films of water under the influence of MHz surface acoustic waves

    CERN Document Server

    Altshuler, Gennady

    2015-01-01

    We use both theory and experiment to study the response of partially wetting films of water and surfactant solutions to a propagating MHz vibration in the solid substrate in the form of a Rayleigh surface acoustic wave (SAW). The SAW invokes a drift of mass in the liquid film that, balanced by capillary stress, may support dynamic wetting and de-wetting along the path of the SAW. The motion of the film is governed by a non-dimensional parameter, $\\theta^3/{\\rm We}$, where $\\theta$ is the three phase contact angle and ${\\rm We}\\equiv \\rho U^2H/\\gamma$; $\\rho,~\\gamma$, $H$, and $U$ are the liquid density, liquid/vapour surface tension, film thickness, and the intensity of the SAW at the solid surface, respectively. We show partially wetting films of water and surfactant solutions atop a lithium niobate substrate, for which $\\theta^3/{\\rm We}>1$, undergo qualitatively different dynamics to fully wetting films of silicon oil, for which $\\theta^3/{\\rm We}\\ll1$, and further explore an intermediate parameter region ...

  20. Influence of the near-surface water film thickness on the characteristics and conditions of water-coal fuel particles inflammation

    Directory of Open Access Journals (Sweden)

    Syrodoy Samen

    2017-01-01

    Full Text Available The results of experimental studies of thermal pretreatment processes complex and inflammation of water coal fuel’s particles (WCF, which surface is covered with water film, have been presented there. The research has been carried out with using of three fuel types (cannel coal, coal B and filter cake: they have essentially different thermo physical characteristics. The results of our studies have been shown that the dynamics of the near-surface water film evaporation and fuel inflammation depends significantly on coal type. It has also been analyzed the influence of water layer thickness on the conditions of WCF particles inflammation. It has been established the time of water film evaporation is about 70% due to the whole induction period.

  1. Influence of water content in mixed solvent on surface morphology, wettability, and photoconductivity of ZnO thin films.

    Science.gov (United States)

    Zhao, Min; Shang, Fengjiao; Lv, Jianguo; Song, Ying; Wang, Feng; Zhou, Zhitao; He, Gang; Zhang, Miao; Song, Xueping; Sun, Zhaoqi; Wei, Yiyong; Chen, Xiaoshuang

    2014-01-01

    ZnO thin films have been synthesized by means of a simple hydrothermal method with different solvents. The effect of deionized water content in the mixed solvents on the surface morphology, crystal structure, and optical property has been investigated by scanning electron microscopy, X-ray diffraction, and UV-Vis spectrophotometer. A large number of compact and well-aligned hexagonal ZnO nanorods and the maximal texture coefficient have been observed in the thin film, which is grown in the mixed solvent with x = 40%. A lot of sparse, diagonal, and pointed nanorods can be seen in the ZnO thin film, which is grown in the 40-mL DI water solution. The optical band gap decreases firstly and then increases with the increase of x. Reversible wettability of ZnO thin films were studied by home-made water contact angle apparatus. Reversible transition between hydrophobicity and hydrophilicity may be attributed to the change of surface chemical composition, surface roughness and the proportion of nonpolar planes on the surface of ZnO thin films. Photocurrent response of ZnO thin films grown at different solvents were measured in air. The response duration of the thin film, which is grown in the solvent with x = 40%, exhibits a fast growth in the beginning but cannot approach the saturate current value within 100 s. The theoretical mechanism for the slower growth or decay duration of the photocurrent has been discussed in detail.

  2. Surface Morphology and Growth of Anodic Titania Nanotubes Films: Photoelectrochemical Water Splitting Studies

    Directory of Open Access Journals (Sweden)

    Chin Wei Lai

    2015-01-01

    become the most studied material as they exhibit promising functional properties. In the present study, anodic TiO2 films with different surface morphologies can be synthesized in an organic electrolyte of ethylene glycol (EG by controlling an optimum content of ammonium fluoride (NH4F using electrochemical anodization technique. Based on the results obtained, well-aligned and bundle-free TiO2 nanotube arrays with diameter of 100 nm and length of 8 µm were successfully synthesized in EG electrolyte containing ≈5 wt% of NH4F for 1 h at 60 V. However, formation of nanoporous structure and compact oxide layer would be favored if the content of NH4F was less than 5 wt%. In the photoelectrochemical (PEC water splitting studies, well-aligned TiO2 nanotubular structure exhibited higher photocurrent density of ≈1 mA/cm2 with photoconversion efficiency of ≈2% as compared to the nanoporous and compact oxide layer due to the higher active surface area for the photon absorption to generate more photo-induced electrons during photoexcitation stage.

  3. Hydrate film growth on the surface of a gas bubble suspended in water.

    Science.gov (United States)

    Peng, B Z; Dandekar, A; Sun, C Y; Luo, H; Ma, Q L; Pang, W X; Chen, G J

    2007-11-01

    The lateral film growth rate of CH4, C2H4, CO2, CH4 + C2H4, and CH4 + C3H8 hydrates in pure water were measured at four fixed temperatures of 273.4, 275.4, 277.4, and 279.4 K by means of suspending a single gas bubble in water. The results showed that the lateral growth rates of mixed-gas CH4 + C2H4 hydrate films were slower than that of pure gas (CH4 or C2H4) for the same driving force and that of mixed-gas CH4 + C3H8 hydrate film growth was the slowest. The dependence of the thickness of hydrate film on the driving force was investigated, and it was demonstrated that the thickness of hydrate film was inversely proportional to the driving force. It was found that the convective heat transfer control model reported in the literature could be used to formulate the lateral film growth rate v(f) with the driving force DeltaT perfectly for all systems after introduction of the assumption that the thickness of hydrate films is inversely proportional to the driving force DeltaT; i.e., v(f) = psiDeltaT(5/2) is correct and independent of the composition of gas and the type of hydrate. The thicknesses of different gas hydrate films were estimated, and it is demonstrated that the thicknesses of mixed-gas hydrate films were thicker than those of pure gases, which was qualitatively consistent with the experimental result.

  4. Very High Surface Area Mesoporous Thin Films of SrTiO3 Grown by Pulsed Laser Deposition and Application to Efficient Photoelectrochemical Water Splitting.

    Science.gov (United States)

    Sangle, Abhijeet L; Singh, Simrjit; Jian, Jie; Bajpe, Sneha R; Wang, Haiyan; Khare, Neeraj; MacManus-Driscoll, Judith L

    2016-12-14

    Very high surface area, self-assembled, highly crystalline mesoporous SrTiO3 (STO) thin films were developed for photoelectrochemical water splitting. Much improved performance of these mesoporous films compared to planar STO thin films and any other form of STO such as single crystal samples and nanostructures was demonstrated. The high performance resulted from very large surface area films and optimization of carrier concentration.

  5. Surface-induced solid-liquid phase transitions in ultra-thin water films at T > 0 ^oC

    Science.gov (United States)

    Chakraborty, Animesh; Gellman, Andrew; Baker, Layton; Broitman, Estebahn

    2008-03-01

    We report here the measurements of both the adsorption isotherms and the dissipation in ultra-thin films of water adsorbed on the surfaces of SiO2 . The measurements were made in a small high vacuum chamber in which we have mounted a QCM. The chamber was evacuated to ˜10-8 Torr and then filled with water vapor at pressures ranging from 10-3 -- 40 Torr (the vapor pressure of water at room temperature is ˜22 Torr). In addition the temperature of the apparatus can be varied in the range 10 -- 60^oC. This is sufficient to measure the adsorption isotherm and to probe the phase of adsorbed water films over the range of conditions. Recently published work studying the adsorption of water on the SiO2 layer formed on Si single crystals has suggested that the phase of the water at temperatures well above 0^oC is actually that of a solid, ice-like structure rather than liquid water [1]. That work is based on the comparison of the vibrational spectrum of thin water films with those of liquid water and ice. In our study we are using the QCM to investigate the possibility of formation of Ice-like structures on SiO2. [1] Asay, D. B. and Kim, S.H., Evolution of the Adsorbed Water Layer Structure on Silicon Oxide at Room Temperature. J. Phys. Chem. B. 2005, 109, 16760-16763

  6. Evaporation of water and uptake of HCl and HBr through hexanol films at the surface of supercooled sulfuric acid.

    Science.gov (United States)

    Glass, Samuel V; Park, Seong-Chan; Nathanson, Gilbert M

    2006-06-22

    Vacuum evaporation and molecular beam scattering experiments have been used to monitor the loss of water and dissolution of HCl and HBr in deuterated sulfuric acid at 213 K containing 0 to 100 mM hexanol. The addition of 1-hexanol to the acid creates a surface film of hexyl species. This film becomes more compact with decreasing acidity, ranging from approximately 62% to approximately 68% of maximum packing on 68 to 56 wt % D(2)SO(4), respectively. D(2)O evaporation from 68 wt % acid remains unaltered by the hexyl film, where it is most porous, but is impeded by approximately 20% from 56 and 60 wt % acid. H --> D exchange experiments further indicate that the hexyl film on 68 wt % acid enhances conversion of HCl and HBr into DCl and DBr, which is interpreted as an increase in HCl and HBr entry into the bulk acid. For this permeable hexyl film, the hydroxyl groups of surface hexanol molecules may assist uptake by providing extra sites for HCl and HBr hydrogen bonding and dissociation. In contrast, HCl --> DCl exchange in 60 wt % D(2)SO(4) at first rises with hexyl surface coverage but then drops back to the bare acid value as the hexyl species pack more tightly. HCl entry is actually diminished by the hexyl film on 56 wt % acid, where the film is most compact. These experiments reveal a transition from a porous hexanol film on 68 wt % sulfuric acid that enhances HCl and HBr uptake to one on 56 wt % acid that slightly impedes HCl and D(2)O transport.

  7. An experimental study on the characteristics of wind-driven surface water film flows by using a multi-transducer ultrasonic pulse-echo technique

    Science.gov (United States)

    Liu, Yang; Chen, Wen-Li; Bond, Leonard J.; Hu, Hui

    2017-01-01

    An experimental study was conducted to investigate the characteristics of surface water film flows driven by boundary layer winds over a test plate in order to elucidate the underlying physics pertinent to dynamic water runback processes over ice accreting surfaces of aircraft wings. A multi-transducer ultrasonic pulse-echo (MTUPE) technique was developed and applied to achieve non-intrusive measurements of water film thickness as a function of time and space to quantify the transient behaviors of wind-driven surface water film flows. The effects of key controlling parameters, including freestream velocity of the airflow and flow rate of the water film, on the dynamics of the surface water runback process were examined in great details based on the quantitative MTUPE measurements. While the thickness of the wind-driven surface water film was found to decrease rapidly with the increasing airflow velocity, various surface wave structures were also found to be generated at the air/water interface as the surface water runs back. The evolution of the surface wave structures, in the terms of wave shape, frequency and propagation velocity of the surface waves, and instability modes (i.e., well-organized 2-D waves vs. 3-D complex irregular waves), was found to change significantly as the airflow velocity increases. Such temporally synchronized and spatially resolved measurements are believed to be very helpful to elucidate the underlying physics for improved understanding of the dynamics of water runback process pertinent to aircraft icing phenomena.

  8. Multifunctional thin film surface

    Energy Technology Data Exchange (ETDEWEB)

    Brozik, Susan M.; Harper, Jason C.; Polsky, Ronen; Wheeler, David R.; Arango, Dulce C.; Dirk, Shawn M.

    2015-10-13

    A thin film with multiple binding functionality can be prepared on an electrode surface via consecutive electroreduction of two or more aryl-onium salts with different functional groups. This versatile and simple method for forming multifunctional surfaces provides an effective means for immobilization of diverse molecules at close proximities. The multifunctional thin film has applications in bioelectronics, molecular electronics, clinical diagnostics, and chemical and biological sensing.

  9. Harvesting water wave energy by asymmetric screening of electrostatic charges on a nanostructured hydrophobic thin-film surface.

    Science.gov (United States)

    Zhu, Guang; Su, Yuanjie; Bai, Peng; Chen, Jun; Jing, Qingshen; Yang, Weiqing; Wang, Zhong Lin

    2014-06-24

    Energy harvesting from ambient water motions is a desirable but underexplored solution to on-site energy demand for self-powered electronics. Here we report a liquid-solid electrification-enabled generator based on a fluorinated ethylene propylene thin film, below which an array of electrodes are fabricated. The surface of the thin film is charged first due to the water-solid contact electrification. Aligned nanowires created on the thin film make it hydrophobic and also increase the surface area. Then the asymmetric screening to the surface charges by the waving water during emerging and submerging processes causes the free electrons on the electrodes to flow through an external load, resulting in power generation. The generator produces sufficient output power for driving an array of small electronics during direct interaction with water bodies, including surface waves and falling drops. Polymer-nanowire-based surface modification increases the contact area at the liquid-solid interface, leading to enhanced surface charging density and thus electric output at an efficiency of 7.7%. Our planar-structured generator features an all-in-one design without separate and movable components for capturing and transmitting mechanical energy. It has extremely lightweight and small volume, making it a portable, flexible, and convenient power solution that can be applied on the ocean/river surface, at coastal/offshore areas, and even in rainy places. Considering the demonstrated scalability, it can also be possibly used in large-scale energy generation if layers of planar sheets are connected into a network.

  10. The configuration of water on rough natural surfaces: Implications for understanding air-water interfacial area, film thickness, and imaging resolution

    Science.gov (United States)

    Kibbey, Tohren C. G.

    2013-08-01

    Previous studies of air-water interfacial areas in unsaturated porous media have often distinguished between interfacial area corresponding to water held by capillary forces between grains and area corresponding to water associated with solid surfaces. The focus of this work was on developing a better understanding of the nature of interfacial area associated with solid surfaces following drainage of porous media. Stereoscopic scanning electron microscopy was used to determine surface elevation maps for eight different surfaces of varying roughness. An algorithm was developed to calculate the true configuration of an air-water interface in contact with the solid surface as a function of capillary pressure. The algorithm was used to calculate surface-associated water configurations for capillary pressures ranging from 10 to 100 cm water. The results of the work show that, following drainage, the configuration of surface-associated water is dominated by bridging of macroscopic surface roughness features over the range of capillary pressures studied, and nearly all of the surface-associated water is capillary held. As such, the thicknesses of surface-associated water were found to be orders-of-magnitude greater than might be expected at the same capillary pressures based on calculations of adsorbed film thickness. The fact that capillary forces in air-water interfaces dominate surface-associated water configuration means that interface shapes are largely unaffected by microscopic surface roughness, and interfaces are considerably smoother than the underlying solid. As such, calculations suggest that microscopic surface roughness likely has minimal impact on the accuracy of surface-associated air-water interfacial areas determined by limited-resolution imaging methods such as computed microtomography.

  11. Increase in the water contact angle of composite film surfaces caused by the assembly of hydrophilic nanocellulose fibrils and nanoclay platelets.

    Science.gov (United States)

    Wu, Chun-Nan; Saito, Tsuguyuki; Yang, Quanling; Fukuzumi, Hayaka; Isogai, Akira

    2014-08-13

    Controlling the assembly modes of different crystalline nanoparticles in composites is important for the expression of specific characteristics of the assembled structures. We report a unique procedure for increasing water contact angles (CAs) of composite film surfaces via the assembly of two different hydrophilic components, nanocellulose fibrils and nanoclay platelets. The nanocellulose fibrils and nanoclay platelets used have ionic groups on their surfaces in high densities (∼1 mmol g(-1)) and have no hydrophobic surface. The increase in the CA of the nanocellulose/nanoclay composite films was thus analyzed on the basis of the air area fractions of their nanostructured surfaces following Cassie's law. The air area fractions were geographically estimated from the atomic force microscopy height profiles of the composite film surfaces. The CAs of the composite film surfaces were found to be well described by Cassie's law. Interestingly, the composite films consisting of two hydrophilic nanoelements with different shapes exhibited CAs larger than those of the individual neat films.

  12. Surface aspects of sol-gel derived hematite films for the photoelectrochemical oxidation of water.

    Science.gov (United States)

    Herrmann-Geppert, Iris; Bogdanoff, Peter; Radnik, Jörg; Fengler, Steffen; Dittrich, Thomas; Fiechter, Sebastian

    2013-02-07

    α-Fe(2)O(3) (hematite) photoanodes for the oxygen evolution reaction (OER) were prepared by a cost-efficient sol-gel procedure. Due to low active photoelectrochemical properties observed, it is assumed that the sol-gel procedure leads to hematite films with defects and surface states on which generated charge carriers are recombined or immobilized in trap processes. Electrochemical activation was proven to diminish unfavourable surface groups to some extent. More efficiently, a plasma treatment improves significantly the photoelectrochemical properties of the OER. X-ray photoelectron spectroscopy (XPS) analysis reveals an oxygen enriched surface layer with new oxygen species which may be responsible for the improved electrochemical activity. Due to surface photovoltage an increased fraction of transferred charge carriers from these newly produced surface defects are identified.

  13. Surface Water & Surface Drainage

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

  14. Surface modifications of chalcopyrite CuInS2 thin films for photochatodes in photoelectrochemical water splitting under sunlight irradiation

    Science.gov (United States)

    Gunawan; Haris, A.; Widiyandari, H.; Septina, W.; Ikeda, S.

    2017-02-01

    Copper chalcopyrite semiconductors include a wide range of compounds that are of interest for photoelectrochemical water splitting which enables them to be used as photochatodes for H2 generation. Among them, CuInS2 is one of the most important materials due to its optimum band gap energy for sunlight absorption. In the present study, we investigated the application of CuInS2 fabricated by electrodeposition as photochatodes for water splitting. Thin film of CuInS2 chalcopyrite was formed on Mo-coated glass substrate by stacked electrodeposition of copper and indium followed by sulfurization under H2S flow. The films worked as a H2 liberation electrode under cathodic polarization from a solution containing Na2SO4 after loading Pt deposits on the film. Introduction of an n-type CdS layer by chemical bath deposition on the CuInS2 surface before the Pt loading resulted appreciable improvements of H2 liberation efficiency and a higher photocurrent onset potential. Moreover, the use of In2S3 layer as an alternative n-type layer to the CdS significantly improved the H2 liberation performance: the CuInS2 film modified with In2S3 and Pt deposits worked as an efficient photocathode for photoelectrochemical water splitting.

  15. Surface Film Adsorption and Lubricity of Soybean Oil In-Water Emulsion and Triblock Copolymer Aqueous Solution: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Reza Taheri

    2016-12-01

    Full Text Available This paper investigates the surface film adsorption and lubricity of two different types of potential environmentally friendly cold metal forming lubricants: soybean vegetable oil in water VO/W emulsions and triblock copolymer aqueous solutions. The lubricants have different visual appearance, surface film adsorption characteristic, lubricity and surface cleaning behaviour. The effects of concentration, temperature and emulsification ultrasonic energy (for VO/W emulsion are studied. The result shows that the soybean VO/W emulsions have stronger adsorption, superior lubricity and anti-wear property compared to the copolymer solutions. The effect of temperature is investigated at 30 °C and 65 °C which are below and above cloud point of the aqueous copolymer solutions. Both lubricants show improved friction and anti-wear property at 65 °C. However, tenacious residual film remained on the discs surface after surface cleaning indicates lower cleanability of the soybean VO/W emulsions compared to the copolymer solutions, postulating the need for extra post-processing cleaning operations after cold forming process with VO/W emulsion lubricant.

  16. Adsorption and reaction of trace gas-phase organic compounds on atmospheric water film surfaces: a critical review.

    Science.gov (United States)

    Donaldson, D J; Valsaraj, Kalliat T

    2010-02-01

    The air-water interface in atmospheric water films of aerosols and hydrometeors (fog, mist, ice, rain, and snow) presents an important surface for the adsorption and reaction of many organic trace gases and gaseous reactive oxidants (hydroxyl radical (OH(.)), ozone (O(3)), singlet oxygen (O(2)((1)Delta(g))), nitrate radicals (NO(3)(.)), and peroxy radicals (RO(2)(.)). Knowledge of the air-water interface partition constant of hydrophobic organic species is necessary for elucidating the significance of the interface in atmospheric fate and transport. Various methods of assessing both experimental and theoretical values of the thermodynamic partition constant and adsorption isotherm are described in this review. Further, the reactivity of trace gases with gas-phase oxidants (ozone and singlet oxygen) at the interface is summarized. Oxidation products are likely to be more water-soluble and precursors for secondary organic aerosols in hydrometeors. Estimation of characteristic times shows that heterogeneous photooxidation in water films can compete effectively with homogeneous gas-phase reactions for molecules in the atmosphere. This provides further support to the existing thesis that reactions of organic compounds at the air-water interface should be considered in gas-phase tropospheric chemistry.

  17. Standard Test Method for Hydrophobic Surface Films by the Water-Break Test

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers the detection of the presence of hydrophobic (nonwetting) films on surfaces and the presence of hydrophobic organic materials in processing ambients. When properly conducted, the test will enable detection of molecular layers of hydrophobic organic contaminants. On very rough or porous surfaces, the sensitivity of the test may be significantly decreased. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  18. Influence of Absorption of Thermal Radiation in the Surface Water Film on the Characteristics and Ignition Conditions

    Directory of Open Access Journals (Sweden)

    Syrodoy Samen V.

    2016-01-01

    Full Text Available The results of the mathematical modeling of homogeneous particle ignition process of coal-water fuel covered with water film have been presented in article. The set co-occurring physical (inert heating, evaporation of water film and thermochemical (thermal degradation, inflammation process have been considered. Heat inside the film has been considered as the model of radiation-conductive heat transfer. Delay times have been determined according to the results of numerical modeling of the ignition. It has been shown that the water film can have a significant impact on performance and the ignition conditions. It has been found that heating main fuel layer occurs in the process of evaporation of water film. For this reason, the next (after the evaporation of the water film thermal preparation (coal heating, thermal decomposition of the organic part of the fuel and inflammation occur faster.

  19. Effect of Surface Passivation on Photoelectrochemical Water Splitting Performance of WO3 Vertical Plate-Like Films

    Directory of Open Access Journals (Sweden)

    Yahui Yang

    2015-11-01

    Full Text Available WO3 vertical plate-like arrays provide a direct pathway for charge transport, and thus hold great potential as working electrodes for photoelectrochemical (PEC water splitting. However, surface recombination due to surface defects hinders the performance improvement. In this work, WO3 vertical plate-like arrays films with HfO2 passivation layer were fabricated via a simple dip-coating method. In the images of transmission electron microscope, a fluffy layer and some small sphere particles existed on the surface of WO3 plate. X-ray photoelectron spectroscopy (XPS showed a higher concentration of Hf element than the result of energy-dispersive X-ray spectroscopy (EDX, which means that HfO2 is rich on the surface of WO3 plates. A higher photocurrent under visible light irradiation was gained with surface passivation. Meanwhile, the results of intensity modulated photocurrent spectrum (IMPS and incident photon to current conversion efficiency (IPCE indicate that HfO2 passivation layer, acting as a barrier for the interfacial recombination, is responsible for the improved photoelectrochemical performance of WO3 vertical plate-like arrays film.

  20. A Simulation Study on Effect of SurfaceFilm-Forming{1mmMaterial on Water Evaporation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A greenhouse experiment was conducted to investigate the effect ofsurface film-forming material (SFFM), a mixture of1618-octadecanols by emulsification, on water evaporation.Air-dried soil with distilled water was incubated firstly for 7 days toreestablish soil biological activity and then for another 7 days aftertreated with SFFM at rates of 0, 1, 2, 4, 6 and 8 g m{-2,respectively. Everyday during the 7-day incubation after addition ofSFFM, water losses due to evaporation were measured by an electronicbalance. The rate of water evaporation with the addition of SFFM wasreduced significantly compared with the control treatment and theeffectiveness of SFFM on water evaporation reduced with time. Accordingto the equation expressions of the effect of SFFM on water evaporation,the half-life of effectiveness of SFFM on water evaporation wasintroduced and calculated to analyze quantitative relationship betweenthe effectiveness of SFFM on water evaporation and the addition rate ofSFFM. The calculated half-life increased with the addition rate of SFFMand the confidence of the calculated values of the half-life was high,suggesting that the half-life of effectiveness of SFFM on waterevaporation could be described quantitatively and may be helpful forameliorating application method of SFFM and screening surface-filmforming materials in order to improve nitrogen fertilizer useefficiency in flooded rice fields.

  1. Crystalline order of a water/glycine film coadsorbed on the (104) calcite surface.

    Science.gov (United States)

    Magdans, Uta; Torrelles, Xavier; Angermund, Klaus; Gies, Hermann; Rius, Jordi

    2007-04-24

    For biomineralization processes, the interaction of the surface of calcite crystals with organic molecules is of particular importance. Especially, biologically controlled biomineralization as in exoskeletons of mollusks and echinoderms, e.g., sea urchin with single-crystal-like spines and shells,1-3 requires molecular control of seed formation and growth process. So far, experiments showing the obvious influence of organic molecules on the morphology and habit of calcite crystals have demonstrated the molecular dimension of the interaction.4-7 Details of the kinetics of growth and dissolution of mineral surfaces influenced by additives are available,8,9 but other experimental data about the structure of the organic/inorganic interface on the atomic scale are rare. On the other hand, complicated organic macromolecules which are involved in biomineralization are numerous, with only a small fraction solved in structure and function so far.10-13 Therefore, model systems have to be designed to provide a basic understanding for the interaction process.14 Using grazing incidence X-ray diffraction combined with molecular modeling techniques, we show that glycine molecules order periodically on the calcite (104) face in competition with the solvent water when exposed to an aqueous solution of the most simple amino acid. In contrast to the general concept of the charge-matching fit of organic molecules on mineral surfaces,4,14 glycine is not attached to the calcite surface directly but substitutes for water molecules in the second hydration layer.

  2. Fabrication of polyamide thin-film nanocomposite membranes with enhanced surface charge for nitrate ion removal from water resources.

    Science.gov (United States)

    Ghaee, A; Zerafat, M M; Askari, P; Sabbaghi, S; Sadatnia, B

    2017-03-01

    Exclusion due to membrane surface charge is considered as one of the main separation mechanisms occurring in charged membranes, which can be varied through various approaches to affect membrane rejection performance. In this study, thin-film composite (TFC) polyamide (PA) membranes were fabricated via interfacial polymerization of m-phenylenediamine (m-PDA) and 2,4-diaminobenzene sulfonic acid with trimesoyl chloride (TMC) on a polysulfone sub-layer. The ability of the prepared membrane to remove nitrate ions from water resources has been investigated. In order to improve membrane permeability, zeolite-PA thin film nanocomposite (TFN) membranes were fabricated by incorporating natural zeolite nanoparticles obtained through ball milling of an Iranian natural zeolite powder in the interfacial polymerization process. The size, morphology and specific surface area of the as-obtained nanozeolite were characterized using particle size analysis, FE-SEM and BET. The functional groups, morphology and surface charge of the membrane were characterized using ATR-FTIR, SEM and zeta potential analyses. Also, field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) were used to determine the distribution of nanozeolite in TFN membranes. The influence of zeolite addition to surface roughness was accessed by atomic force microscopy. The performance of TFC and TFN membranes was evaluated in terms of pure water flux and nitrate rejection. The results showed that in case of sulfonated diamine, nitrate ions rejection was enhanced from 63% to 85% which could be attributed to surface charge enhancement. TFN permeability was almost doubled by the addition of nanozeolite.

  3. Salicylic acid electrooxidation. A surface film formation

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  4. Capacitor film surface assessment studies

    Science.gov (United States)

    Galperin, I.; White, W.

    1985-02-01

    In the present investigation of the optical surface of the three widely used, biaxially oriented capacitor films, polypropylene, polyvinylidene fluoride, and polyester, with attention to film surface defects and thickness variation, the defects and their rate of occurrence proved traceable in terms of polymer structure, chemical grouping, and fabrication processing. Film thickness variation was small, yet differed for each film type. Film breakdown voltages have been determined, and alternative causes for the voltage values obtained are proposed. A reciprocal relation is noted between the film breakdown voltage and the dielectric constant.

  5. RF-PACVD of water repellent and protective HMDSO coatings on bell metal surfaces: Correlation between discharge parameters and film properties

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, A.J. [Materials Science Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati 781035, Assam (India); Barve, S.A. [Laser and Plasma Technology Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Chutia, Joyanti, E-mail: joyanti_c@sify.com [Materials Science Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati 781035, Assam (India); Pal, A.R. [Materials Science Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Guwahati 781035, Assam (India); Kishore, R. [Material Science Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Jagannath [Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Pande, M. [High Pressure Physics Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Patil, D.S. [Laser and Plasma Technology Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India)

    2011-08-01

    Hexamethyldisiloxane (HMDSO) films have been deposited on bell metal using radiofrequency plasma assisted chemical vapor deposition (RF-PACVD) technique. The protective performances of the HMDSO films and their water repellency have been investigated as a function of DC self-bias voltage on the substrates during deposition. Plasma potential measurements during film deposition process are carried out by self-compensated emissive probe. Optical emission spectroscopy (OES) analyses of the plasma during deposition reveal no significant change in the plasma composition within the DC self-bias voltage range of -40 V to -160 V that is used. Raman and X-ray photoelectron spectroscopy (XPS) studies are carried out for film chemistry analysis and indicate that the impinging ion energy on the substrates influences the physio-chemical properties of the HMDSO films. At critical ion energy of 113 qV (corresponding to DC self-bias voltage of -100 V), the deposited HMDSO film exhibits least defective Si-O-Si chemical structure and highest inorganic character and this contributes to its best corrosion resistance behavior. The hardness and elastic modulus of the films are found to be bias dependent and are 1.27 GPa and 5.36 GPa for films deposited at -100 V. The critical load for delamination is also bias dependent and is 11 mN for this film. The water repellency of the HMDSO films is observed to be dependent on the variation in surface roughness. The results of the investigations suggest that HMDSO films deposited by RF-PACVD can be used as protective coatings on bell metal surfaces.

  6. Surface characteristics of PLA and PLGA films

    Energy Technology Data Exchange (ETDEWEB)

    Paragkumar N, Thanki [Laboratoire de Chimie-Physique Macromoleculaire (LCPM), UMR CNRS-INPL 7568, Groupe ENSIC, 1 rue Grandville, B.P. 20451, 54001 Nancy Cedex (France); Edith, Dellacherie [Laboratoire de Chimie-Physique Macromoleculaire (LCPM), UMR CNRS-INPL 7568, Groupe ENSIC, 1 rue Grandville, B.P. 20451, 54001 Nancy Cedex (France); Six, Jean-Luc [Laboratoire de Chimie-Physique Macromoleculaire (LCPM), UMR CNRS-INPL 7568, Groupe ENSIC, 1 rue Grandville, B.P. 20451, 54001 Nancy Cedex (France)]. E-mail: Jean-Luc.Six@ensic.inpl-nancy.fr

    2006-12-30

    Surface segregation and restructuring in polylactides (poly(D,L-lactide) and poly(L-lactide)) and poly(D,L-lactide-co-glycolide) (PLGA) films of various thicknesses were investigated using both attenuated total reflection FTIR (ATR-FTIR) and contact angle relaxation measurements. In case of poly(D,L-lactide) (DLPLA), it was observed that the surface segregation and the surface restructuring of methyl side groups are influenced by the polymer film thickness. This result has been confirmed by X-ray photoelectron spectroscopy (XPS). In the same way, PLGA thick films were also characterized by an extensive surface segregation of methyl side groups. Finally, surface restructuring was investigated by dynamic contact angle measurements and it was observed when film surface comes into contact with water. In parallel, we also found that poly(L-lactide) (PLLA) thin and clear films with thickness {approx}15 {mu}m undergo conformational changes on the surface upon solvent treatment with certain solvents. The solvent treated surface of PLLA becomes hazy and milky white and its hydrophobicity increases compared to untreated surface. FTIR spectroscopic analysis indicated that polymer chains at the surface undergo certain conformational changes upon solvent treatment. These changes are identified as the restricted motions of C-O-C segments and more intense and specific vibrations of methyl side groups. During solvent treatment, the change in water contact angle and FTIR spectrum of PLLA is well correlated.

  7. Crystallinity of the double layer of cadmium arachidate films at the water surface

    DEFF Research Database (Denmark)

    Leveiller, F.; Jacquemain, D.; Lahav, M.

    1991-01-01

    A crystalline counterionic layer at the interface between an electrolyte solution and a charged layer of insoluble amphiphilic molecules was observed with grazing incidence synchrotron x-ray diffraction. Uncompressed arachidic films spread over 10(-3) molar cadmium chloride solution (pH 8.8) spon....... The reflections from the Cd2+ layer were indexed according to a 2 X 3 supercell of the arachidate lattice with three Cd2+ ions per cadmium unit cell....

  8. Silk film biomaterials for ocular surface repair

    Science.gov (United States)

    Lawrence, Brian David

    Current biomaterial approaches for repairing the cornea's ocular surface upon injury are partially effective due to inherent material limitations. As a result there is a need to expand the biomaterial options available for use in the eye, which in turn will help to expand new clinical innovations and technology development. The studies illustrated here are a collection of work to further characterize silk film biomaterials for use on the ocular surface. Silk films were produced from regenerated fibroin protein solution derived from the Bombyx mori silkworm cocoon. Methods of silk film processing and production were developed to produce consistent biomaterials for in vitro and in vivo evaluation. A wide range of experiments was undertaken that spanned from in vitro silk film material characterization to in vivo evaluation. It was found that a variety of silk film properties could be controlled through a water-annealing process. Silk films were then generated that could be use in vitro to produce stratified corneal epithelial cell sheets comparable to tissue grown on the clinical standard substrate of amniotic membrane. This understanding was translated to produce a silk film design that enhanced corneal healing in vivo on a rabbit injury model. Further work produced silk films with varying surface topographies that were used as a simplified analog to the corneal basement membrane surface in vitro. These studies demonstrated that silk film surface topography is capable of directing corneal epithelial cell attachment, growth, and migration response. Most notably epithelial tissue development was controllably directed by the presence of the silk surface topography through increasing cell sheet migration efficiency at the individual cellular level. Taken together, the presented findings represent a comprehensive characterization of silk film biomaterials for use in ocular surface reconstruction, and indicate their utility as a potential material choice in the

  9. Thin Ice Films at Mineral Surfaces.

    Science.gov (United States)

    Yeşilbaş, Merve; Boily, Jean-François

    2016-07-21

    Ice films formed at mineral surfaces are of widespread occurrence in nature and are involved in numerous atmospheric and terrestrial processes. In this study, we studied thin ice films at surfaces of 19 synthetic and natural mineral samples of varied structure and composition. These thin films were formed by sublimation of thicker hexagonal ice overlayers mostly produced by freezing wet pastes of mineral particles at -10 and -50 °C. Vibration spectroscopy revealed that thin ice films contained smaller populations of strongly hydrogen-bonded water molecules than in hexagonal ice and liquid water. Thin ice films at the surfaces of the majority of minerals considered in this work [i.e., metal (oxy)(hydr)oxides, phyllosilicates, silicates, volcanic ash, Arizona Test Dust] produced intense O-H stretching bands at ∼3400 cm(-1), attenuated bands at ∼3200 cm(-1), and liquid-water-like bending band at ∼1640 cm(-1) irrespective of structure and composition. Illite, a nonexpandable phyllosilicate, is the only mineral that stabilized a form of ice that was strongly resilient to sublimation in temperatures as low as -50 °C. As mineral-bound thin ice films are the substrates upon which ice grows from water vapor or aqueous solutions, this study provides new constraints from which their natural occurrences can be understood.

  10. Surface wrinkling on polydopamine film

    Science.gov (United States)

    Meng, Jieyun; Xie, Jixun; Han, Xue; Lu, Conghua

    2016-05-01

    In this paper, we report a non-lithographic strategy to realize surface patterns on polydopamine films. It is based on surface wrinkling, which is induced on polydopamine (PDA) films that are grown on uniaxially pre-strained polydimethylsiloxane (PDMS) substrates through self-polymerization of dopamine, followed by the pre-strain release. We investigate the influences of the experimental conditions including polymerization time, prestrain and the dopamine solution concentration on the wrinkling patterns. Furthermore, we take advantage of the reducibility of PDA to fabricate silver nanoparticle-deposited PDA films with surface-wrinkled patterns, which may have potential applications in the related fields.

  11. Impact of water quality on removal of carbamazepine in natural waters by N-doped TiO{sub 2} photo-catalytic thin film surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Avisar, Dror, E-mail: drorvi@post.tau.ac.il [The Hydro-Chemistry Laboratory, Faculty of Geography and the Environment, Tel Aviv University, Tel Aviv 69978 (Israel); Horovitz, Inna [The Hydro-Chemistry Laboratory, Faculty of Geography and the Environment, Tel Aviv University, Tel Aviv 69978 (Israel); School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Lozzi, Luca; Ruggieri, Fabrizio [Department of Physical and Chemical Sciences, University of L’Aquila, Via Vetoio, I-67010 Coppito, L’Aquila (Italy); Baker, Mark; Abel, Marie-Laure [The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Mamane, Hadas [School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

    2013-01-15

    Highlights: ► N-doped TiO{sub 2} thin films have been deposited by sol–gel dip-coating. ► CBZ removal improved with increasing medium pH in the range of 5–9. ► DOC at a concentration of 5 mg/L resulted in an ∼20% reduction in CBZ removal. ► Alkalinity values of 100 mg/L as CaCO{sub 3} resulted in a 40% decrease in CBZ removal. ► Complete suppression of the photocatalytic process in wastewater effluent. -- Abstract: Photocatalytic experiments on the pharmaceutical pollutant carbamazepine (CBZ) were conducted using sol–gel nitrogen-doped TiO{sub 2}-coated glass slides under a solar simulator. CBZ was stable to photodegradation under direct solar irradiation. No CBZ sorption to the catalyst surface was observed, as further confirmed by surface characterization using X-ray photoelectron spectroscopic analysis of N-doped TiO{sub 2} surfaces. When exposing the catalyst surface to natural organic matter (NOM), an excess amount of carbon was detected relative to controls, which is consistent with NOM remaining on the catalyst surface. The catalyst surface charge was negative at pH values from 4 to 10 and decreased with increasing pH, correlated with enhanced CBZ removal with increasing medium pH in the range of 5–9. A dissolved organic carbon concentration of 5 mg/L resulted in ∼20% reduction in CBZ removal, probably due to competitive inhibition of the photocatalytic degradation of CBZ. At alkalinity values corresponding to CaCO{sub 3} addition at 100 mg/L, an over 40% decrease in CBZ removal was observed. A 35% reduction in CBZ occurred in the presence of surface water compared to complete suppression of the photocatalytic process in wastewater effluent.

  12. Superhydrophobic Cu2S@Cu2O film on copper surface fabricated by a facile chemical bath deposition method and its application in oil-water separation

    Science.gov (United States)

    Pi, Pihui; Hou, Kun; Zhou, Cailong; Li, Guidong; Wen, Xiufang; Xu, Shouping; Cheng, Jiang; Wang, Shuangfeng

    2017-02-01

    Cu2S and Cu2O composite (Cu2S@Cu2O) film with micro/nano binary structure was created on copper surface using the mixing solution of sodium thiosulphate and copper sulfate by a facile chemical bath deposition method. After modification with low-cost polydimethylsioxane (PDMS), the superhydrophobic Cu2S@Cu2O film was obtained. The as-prepared film shows outstanding water repellency with a water contact angle larger than 150° and long-term storage stability. The geometric morphology and chemical composition of the film were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), respectively. Moreover, the same method was used to fabricate superhydrophobic/superoleophilic copper mesh, and it could realize separation of various oily sewages with separation efficiency above 94%. This strategy has potential to fabricate the practical superhydrophobic Cu2S@Cu2O film on copper surface on a large scale due to its simplicity and low cost.

  13. Film boiling on vertical surfaces.

    Science.gov (United States)

    Suryanarayana, N. V.; Merte, H., Jr.

    1972-01-01

    Film boiling of a saturated liquid on a vertical surface is analyzed to determine the local heat-transfer rates as a function of height and heater-surface superheat. Experiments show that the laminar-flow model is inadequate. A turbulent-vapor-flow model is used, and the influence of the interfacial oscillations is incorporated on a semiempirical basis. Measurements of local film boiling were obtained with a transient technique using saturated liquid nitrogen.

  14. Water clustering on nanostructured iron oxide films

    DEFF Research Database (Denmark)

    Merte, Lindsay Richard; Bechstein, Ralf; Peng, G.;

    2014-01-01

    , but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moire-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer...... islands form on the bare film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous...

  15. In situ Raman spectroscopic analysis of surface oxide films on Ni-base alloy/low alloy steel dissimilar metal weld interfaces in high-temperature water

    Science.gov (United States)

    Kim, Jongjin; Choi, Kyung Joon; Bahn, Chi Bum; Kim, Ji Hyun

    2014-06-01

    In situ Raman spectroscopy has been applied to analyze the surface oxide films formed on dissimilar metal weld (DMW) interfaces of nickel-base alloy/low alloy steel under hydrogenated high-temperature water condition. For the analysis of the oxide films under high temperature/pressure aqueous conditions, an in situ Raman spectroscopy system was developed by constructing a hydrothermal cell where the entire optics including the excitation laser and the Raman light collection system were located at the nearest position to the specimen by means of immersion optics. In situ Raman spectra of the DMW interfaces were collected in hydrogenated water condition at different temperatures up to 300 °C. The measured in situ Raman spectra showed peaks of Cr2O3, NiCr2O4 and Fe3O4 at the DMW interface. It is considered that differences in the oxide chemistry originated from the chemical element distribution inside of the DMW interface region.

  16. Surface tension profiles in vertical soap films

    CERN Document Server

    Adami, N

    2013-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed introducing deformable elastic objets in the films. The shape adopted by those objects set in the film can be related to the surface tension value at a given vertical position by numerical solving of adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position in the soap film can be reproduced by simple modeling taking into account film thickness measurements.

  17. Investigation of the influence of liquid water films on O3 and PAN deposition on plant leaf surfaces treated with organic / inorganic compounds

    Science.gov (United States)

    Sun, Shang; Moravek, Alexander; von der Heyden, Lisa; Held, Andreas; Kesselmeier, Jürgen; Sörgel, Matthias

    2016-04-01

    Liquid water films on environmental surfaces play an important role in various fields of interest (Burkhardt and Eiden, 1994). For example, the deposition of water soluble trace gases could be increased by surface moisture. Chameides and Stelson (1992) found out that the dissolution of trace gases in airborne particulate matter increases with rising water/solid ratio of the particles. Further, Flechard et al. (1999) concluded that deliquescent salt particles represent a potential sink for trace gases, depending on their chemical property. The formation of surface water films and its influence on the gas deposition was proposed by many previous studies (Fuentes and Gillespie, 1992, Burkhardt and Eiden, 1994, van Hove et al., 1989, Burkhardt et al., 1999, Flechard et al., 1999). In this study we investigate the influence of leaf surface water films on the deposition of O3 and PAN under controlled laboratory conditions. A twin cuvette system described in Sun et al. (2015) was used to control the environmental parameters such as light, temperature, trace gas mixing ratio and humidity. Furthermore, the leaf surface was treated with various organic and inorganic solutions to investigate the influence of deposited compounds on the electrical surface conductance of the leaves and the surface deposition of O3 and PAN at various relative humidities. The result shows that RHcrit, where the electrical surface conductance (G) increases exponentially, was 40 % during the light period and 50 % during the dark period. Furthermore, we observed that the formation of the leaf surface liquid film was depended on the deposited compounds on the leaf cuticles. For the O3 deposition on plants (Quercus ilex) a clear enhancement at rising environmental air humidity under light and dark condition was found. The increase during light conditions can be related partly to increasing stomatal conductance with higher RH. From the non-stomatal deposition measured in dark experiments, we could

  18. Water Clustering on Nanostructured Iron Oxide Films

    Energy Technology Data Exchange (ETDEWEB)

    Merte, L. R.; Bechstein, Ralf; Peng, Guowen; Rieboldt, Felix; Farberow, Carrie A.; Zeuthen, Helene; Knudsen, Jan; Laegsgaard, E.; Wendt, Stefen; Mavrikakis, Manos; Besenbacher, Fleming

    2014-06-30

    The adhesion of water to solid surfaces is characterized by the tendency to balance competing molecule–molecule and molecule–surface interactions. Hydroxyl groups form strong hydrogen bonds to water molecules and are known to substantially influence the wetting behaviour of oxide surfaces, but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moire´-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer islands form on the are film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous water are found to coexist at adjacent hydroxylated and hydroxyl-free domains of the moire´ structure.

  19. Water clustering on nanostructured iron oxide films.

    Science.gov (United States)

    Merte, Lindsay R; Bechstein, Ralf; Peng, Guowen; Rieboldt, Felix; Farberow, Carrie A; Zeuthen, Helene; Knudsen, Jan; Lægsgaard, Erik; Wendt, Stefan; Mavrikakis, Manos; Besenbacher, Flemming

    2014-06-30

    The adhesion of water to solid surfaces is characterized by the tendency to balance competing molecule-molecule and molecule-surface interactions. Hydroxyl groups form strong hydrogen bonds to water molecules and are known to substantially influence the wetting behaviour of oxide surfaces, but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moiré-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer islands form on the bare film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous water are found to coexist at adjacent hydroxylated and hydroxyl-free domains of the moiré structure.

  20. Surface modification of PE film by DBD plasma in air

    Energy Technology Data Exchange (ETDEWEB)

    Ren, C.-S. [State Key Laboratory of Material Modification by Electron, Ion and Laser Beams, Dalian University of Technology, Dalian 116023 (China)], E-mail: rchsh@dlut.edu.cn; Wang, K.; Nie, Q.-Y.; Wang, D.-Z.; Guo, S.-H. [State Key Laboratory of Material Modification by Electron, Ion and Laser Beams, Dalian University of Technology, Dalian 116023 (China)

    2008-12-30

    In this paper, surface modification of polyethylene (PE) films is studied by dielectric barrier discharge plasma treatment in air. The treated samples were examined by water contact angle measurement, calculation of surface free energy, Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The water contact angle changes from the original value of 93.2{sup o} to the minimum value of 53.3{sup o} and surface free energy increases from 27.3 to 51.89 J/m{sup 2} after treatment time of 50 s. Both ATR and XPS show some oxidized species are introduced into the sample surface by the plasma treatment and that the change tendencies of the water contact angle and surface free energy with the treatment time are the same as that of the oxygen concentration on the treated sample surface. Cu films were deposited on the treated and untreated PE surfaces. The peel adhesive strength between the Cu film and the treated sample is 1.5 MPa, whereas the value is only 0.8 MPa between the Cu film and the untreated PE. SEM pictures show that the Cu film deposited on the plasma treated PE surface is smooth and the crystal grain is smaller, contrarily the Cu film on the untreated PE surface is rough and the crystal grain is larger.

  1. In situ Raman spectroscopic analysis of surface oxide films on Ni-base alloy/low alloy steel dissimilar metal weld interfaces in high-temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongjin; Choi, Kyung Joon [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Bahn, Chi Bum [School of Mechanical Engineering, Pusan National University 2, 63-gil, Geumjeong-Gu, Pusan 609-735 (Korea, Republic of); Kim, Ji Hyun, E-mail: kimjh@unist.ac.kr [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

    2014-06-01

    In situ Raman spectroscopy has been applied to analyze the surface oxide films formed on dissimilar metal weld (DMW) interfaces of nickel-base alloy/low alloy steel under hydrogenated high-temperature water condition. For the analysis of the oxide films under high temperature/pressure aqueous conditions, an in situ Raman spectroscopy system was developed by constructing a hydrothermal cell where the entire optics including the excitation laser and the Raman light collection system were located at the nearest position to the specimen by means of immersion optics. In situ Raman spectra of the DMW interfaces were collected in hydrogenated water condition at different temperatures up to 300 °C. The measured in situ Raman spectra showed peaks of Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} at the DMW interface. It is considered that differences in the oxide chemistry originated from the chemical element distribution inside of the DMW interface region.

  2. Intrinsic instability of thin liquid films on nanostructured surfaces

    Science.gov (United States)

    Rokoni, Arif; Hu, Han; Sun, Liyong; Sun, Ying

    2016-11-01

    The instability of a thin liquid film on nanostructures is not well understood but is important in liquid-vapor two-phase heat transfer (e.g., thin film evaporation and boiling), lubrication, and nanomanufacturing. In thin film evaporation, the comparison between the non-evaporating film thickness and the critical film breakup thickness determines the stability of the film: the film becomes unstable when the critical film breakup thickness is larger than the non-evaporating film thickness. In this study, a closed-form model is developed to predict the critical breakup thickness of a thin liquid film on 2D periodic nanostructures based on minimization of system free energy in the limit of a liquid monolayer. Molecular dynamics simulations are performed for water thin films on square nanostructures of varying depth and wettability and the simulations agree with the model predictions. The results show that the critical film breakup thickness increases with the nanostructure depth and the surface wettability. The model developed here enables the prediction of the minimum film thickness for stable thin film evaporation on a given nanostructure.

  3. Petroleum-collecting and dispersing complexes based on oleic acid and nitrogenous compounds as surface-active agents for removing thin petroleum films from water surface.

    Science.gov (United States)

    Asadov, Ziyafaddin H; Tantawy, Ahmed H; Zarbaliyeva, Ilhama A; Rahimov, Ravan A

    2012-01-01

    Petroleum-collecting and dispersing complexes were synthesized on the basis of oleic acid and nitrogen-containing compounds. Surface-active properties (interfacial tension) of the obtained complexes were investigated by stalagmometric method. Petroleum-collecting and dispersing properties of the oleic acid complexes in diluted (5% wt. water or alcoholic solution) and undiluted form have been studied in waters of varying salinity (distilled, fresh and sea waters). Some of physico-chemical indices of the prepared compounds such as solubility, acid and amine numbers as well as electrical conductivity have been determined. The ability of oleic acid complex with ethylenediamine as petro-collecting and dispersing agent towards different types of petroleum has been studied. The influence of thickness and "age" of the petroleum slick on collecting and dispersing capacity of this complex has been clarified. Surface properties studied included critical micelle concentration (CMC), maximum surface excess (Γ(max)), and minimum surface area (A(min)). Free energies of micellization (ΔG°(mic)) and adsorption (ΔG°(ads)) were calculated.

  4. Water-evaporation reduction by duplex films: application to the human tear film.

    Science.gov (United States)

    Cerretani, Colin F; Ho, Nghia H; Radke, C J

    2013-09-01

    Water-evaporation reduction by duplex-oil films is especially important to understand the physiology of the human tear film. Secreted lipids, called meibum, form a duplex film that coats the aqueous tear film and purportedly reduces tear evaporation. Lipid-layer deficiency is correlated with the occurrence of dry-eye disease; however, in-vitro experiments fail to show water-evaporation reduction by tear-lipid duplex films. We review the available literature on water-evaporation reduction by duplex-oil films and outline the theoretical underpinnings of spreading and evaporation kinetics that govern behavior of these systems. A dissolution-diffusion model unifies the data reported in the literature and identifies dewetting of duplex films into lenses as a key challenge to obtaining significant evaporation reduction. We develop an improved apparatus for measuring evaporation reduction by duplex-oil films including simultaneous assessment of film coverage, stability, and temperature, all under controlled external mass transfer. New data reported in this study fit into the larger body of work conducted on water-evaporation reduction by duplex-oil films. Duplex-oil films of oxidized mineral oil/mucin (MOx/BSM), human meibum (HM), and bovine meibum (BM) reduce water evaporation by a dissolution-diffusion mechanism, as confirmed by agreement between measurement and theory. The water permeability of oxidized-mineral-oil duplex films agrees with those reported in the literature, after correction for the presence of mucin. We find that duplex-oil films of bovine and human meibum at physiologic temperature reduce water evaporation only 6-8% for a 100-nm film thickness pertinent to the human tear film. Comparison to in-vivo human tear-evaporation measurements is inconclusive because evaporation from a clean-water surface is not measured and because the mass-transfer resistance is not characterized.

  5. Surface acoustic wave propagation in graphene film

    Energy Technology Data Exchange (ETDEWEB)

    Roshchupkin, Dmitry, E-mail: rochtch@iptm.ru; Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Irzhak, Dmitry [Institute of Microelectronics Technology and High-Purity Materials Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Ortega, Luc [Laboratoire de Physique des Solides, Univ. Paris-Sud, CNRS, UMR 8502, 91405 Orsay Cedex (France); Zizak, Ivo; Erko, Alexei [Institute for Nanometre Optics and Technology, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Strasse 15, 12489 Berlin (Germany); Tynyshtykbayev, Kurbangali; Insepov, Zinetula [Nazarbayev University Research and Innovation System, 53 Kabanbay Batyr St., Astana 010000 (Kazakhstan)

    2015-09-14

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  6. Surface acoustic wave propagation in graphene film

    Science.gov (United States)

    Roshchupkin, Dmitry; Ortega, Luc; Zizak, Ivo; Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Erko, Alexei; Tynyshtykbayev, Kurbangali; Irzhak, Dmitry; Insepov, Zinetula

    2015-09-01

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  7. Wetting and absorption of water drops on Nafion films.

    Science.gov (United States)

    Goswami, Sharonmoyee; Klaus, Shannon; Benziger, Jay

    2008-08-19

    Water drops on Nafion films caused the surface to switch from being hydrophobic to being hydrophilic. Contact angle hysteresis of >70 degrees between advancing and receding values were obtained by the Wilhelmy plate technique. Sessile drop measurements were consistent with the advancing contact angle; the sessile drop contact angle was 108 degrees . Water drop adhesion, as measured by the detachment angle on an inclined plane, showed much stronger water adhesion on Nafion than Teflon. Sessile water and methanol drops caused dry Nafion films to deflect. The flexure went through a maximum with time. Flexure increased with contact area of the drop, but was insensitive to the film thickness. Methanol drops spread more on Nafion and caused larger film flexure than water. The results suggest that the Nafion surface was initially hydrophobic but water and methanol drops caused hydrophilic sulfonic acid domains to be drawn to the Nafion surface. Local swelling of the film beneath the water drop caused the film to buckle. The maximum flexure is suggested to result from motion of a water swelling front through the Nafion film.

  8. Biocompatibility and Surface Studies of Microwave CVD Diamond Films

    Science.gov (United States)

    Davis, Brian; Garguilo, J. M.; Koeck, F. A. M.; Nemanich, R. J.; Price, K. J.

    2002-03-01

    The structure and surface properties of a variety of diamond and diamond like carbon films were studied at the nano-scale, in an attempt to assess the biocompatibility of these surfaces. The process of microwave chemical vapor deposition was used to deposit undoped diamond, nitrogen doped diamond, diamond with a titanium monolayer, and diamond-like carbon samples. The contact angles of de-ionized water droplets on the surface of the samples were measured to analyze the surface energy of each film. The rms roughness values of the diamond films measured by atomic force microscopy were also used in determining surface characteristics. Surface treatments of hydrogen passivation, and oxidization were applied to the surface of each film. Hydrogen passivation of the undoped diamond, and nitrogen doped diamond surfaces increases the contact angle on average 30 degrees. Oxidation of the surface decreases the contact angle on average 20 degrees. The surface treatments did not significantly change the contact angle of the diamond like carbon films. Protein adsorption is the first event to take place at a tissue/material interface of an implant into the body, and fibrinogen is the major surface protein, which initiates coagulation and inflammation in the body. The adsorption of fibrinogen was used as an indicator of the biocompatibility of these diamond materials. Fibrinogen was applied to the diamond, and diamond like carbon films. A correlation between contact angle/surface energy, roughness, and the fibrinogen adsorption of these diamond surfaces is reported. There was no significant change in the contact angles following the application of fibrinogen to the surface of the films. This could indicate the biocompatibility of the diamond films. This work supported by the NSF REU program at NCSU and a Physical Sciences Student Research grant from MSU.

  9. Surface tension profiles in vertical soap films

    Science.gov (United States)

    Adami, N.; Caps, H.

    2015-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed by introducing deformable elastic objets in the films. The shape adopted by those objects once set in the film is related to the surface tension value at a given vertical position by numerically solving the adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position is predicted by simple modeling that takes into account the mechanical equilibrium of the films coupled to previous thickness measurements.

  10. Surface-water surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Saldi, K.A.; Dirkes, R.L.; Blanton, M.L.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995).

  11. Surface films and corrosion of copper

    Energy Technology Data Exchange (ETDEWEB)

    Hilden, J.; Laitinen, T.; Maekelae, K.; Saario, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

    1999-03-01

    In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of the copper is not expected to be the limiting factor in the waste repository environment when estimating the life-time of the canister construction. However, different forms of localised corrosion, i.e. pitting, stress corrosion cracking, or environmentally assisted creep fracture may cause premature failure of the copper shield. Of the probable constituents in the groundwater, nitrites, chlorides, sulphides and carbonates have been suggested to promote localised corrosion of copper. The main assumption made in planning this research program is that the surface films forming on copper in the repository environment largely determine the susceptibility of copper to the different forms of localised corrosion. The availability of reactants, which also may become corrosion rate limiting, is investigated in several other research programs. This research program consists of a set of successive projects targeted at characterising the properties of surface films on copper in repository environment containing different detrimental anions. A further aim was to assess the significance of the anion-induced changes in the stability of the oxide films with regard to localised corrosion of copper. This report summarises the results from a series of investigations on properties of surface films forming on copper in water of pH = 8.9 at temperature of 80 deg C and pressure of 2 MPa. The main results gained so far in this research program are as follows: The surface films forming on copper in the thermodynamic stability region of monovalent copper at 80 deg C consist of a bulk part (about 1 mm thick) which is a good ionic and electronic conductor, and an outer, interfacial layer (0.001 - 0.005 mm thick) which shows p-type semiconductor

  12. Surface Water in Hawaii

    Science.gov (United States)

    Oki, Delwyn S.

    2003-01-01

    Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

  13. Complete wetting of Pt(111) by nanoscale liquid water films

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuntao; Dibble, Collin J.; Petrik, Nikolay G.; Smith, R. Scott; Kay, Bruce D.; Kimmel, Gregory A.

    2016-02-04

    The melting and wetting of nanoscale crystalline ice films on Pt(111) that are transiently heated above the melting point using nanosecond laser pulses are studied with infrared refection absorption spectroscopy (IRAS) and Kr temperature programmed desorption (TPD). The as-grown crystalline ice films consist of isolated nanoscale ice crystallites embedded in a hydrophobic water monolayer. Upon heating above the melting point, these ice crystallites rapidly melt to form nanoscale droplets of liquid water. Rapid cooling of the system to cryogenic temperatures after each laser pulse quenches the water films and allows them to be interrogated with IRAS, Kr TPD and other ultrahigh vacuum surface science techniques. With each successive heat pulse, these liquid drops spread across the surface until it is entirely covered with multilayer water films after several pulses. These results, which show that nanoscale water films completely wet Pt(111), are in contrast to molecular dynamics simulations predicting partial wetting of nanoscale water drops on a hydrophobic water monolayer. The results provide valuable new insights into the wetting characteristics of nanoscale water films on a clean, well-characterized single crystal surface.

  14. Langmuir films of petroleum at the air-water interface.

    Science.gov (United States)

    Vieira, Vinícius C C; Severino, Divinomar; Oliveira, Osvaldo N; Pavinatto, Felippe J; Zaniquelli, Maria E D; Ramos, Ana Paula; Baptista, Maurício S

    2009-11-03

    Understanding the behavior of petroleum films at the air/water interface is crucial for dealing with oil slicks and reducing the damages to the environment, which has normally been attempted with studies of Langmuir films made of fractions of petroleum. However, the properties of films from whole petroleum samples may differ considerably from those of individual fractions. Using surface pressure and surface potential measurements and Brewster angle and fluorescence microscopy, we show that petroleum forms a nonhomogeneous Langmuir film at the air-water interface. The surface pressure isotherms for petroleum Langmuir films exhibit gas (G), liquid-expanded (LE), and liquid-condensed phases, with almost no hysteresis in the compression-decompression cycles. Domains formed upon compression from the G to the LE phase were accompanied by an increase in fluorescence intensity with excitation at 400-440 nm owing to an increase in the surface density of the chromophores in the petroleum film. The surface pressure and the fluorescence microscopy data pointed to self-assembling domains into a pseudophase in thermodynamic equilibrium with other less emitting petroleum components. This hypothesis was supported by Brewster angle microscopy images, whereby the appearance of water domains even at high surface pressures confirms the tendency of petroleum to stabilize emulsion systems. The results presented here suggest that, for understanding the interaction with water, it may be more appropriate to use the whole petroleum samples rather than its fractions.

  15. surface modification of polyethylene films using atmospheric ...

    African Journals Online (AJOL)

    Dr A.B.Ahmed

    measured an increase of ozone with increasing oxygen admixture. Neither of ... Detailed modeling of both the chemistry inside the plasma and plasma effluent as well as the ... Film Treated by Air Dielectric Barrier Discharge. Plasma. Surface ...

  16. Ellipsometry of functional organic surfaces and films

    CERN Document Server

    Hinrichs, Karsten

    2013-01-01

    Ellipsometry is the method of choice to determin the properties of surfaces and thin films. It provides comprehensive and sensitive characterization in a contactless and non-invasive measurements. This book gives a state-of-the-art survey of ellipsometric investigations of organic films and surfaces, from laboratory to synchrotron applications, with a special focus on in-situ use in processing environments and at solid-liquid interfaces.

  17. Surface structure of oriented PET films

    CERN Document Server

    Kirov, K

    2001-01-01

    crystallinity and the level of molecular orientation of the polymer are highest at the film surface and gradually decrease away from it. The same trend for an increase in structural order nearer the film surface was observed in a series of PET films drawn uniaxially in laboratory conditions. The observed strong dependence of stratification in the oriented films on drawing ratio, lead to the conclusion, that the structural gradients arise as a result of viscous flow. The molecular mechanism of stratification is discussed and leads to the idea of enhanced chain mobility at the PET film surface. The idea is in line with recent studies showing a depression of the glass transition temperature of free polymer surfaces. In addition, the results on structure formation in PET films during drawing, give support to the existing view that polymer crystallisation is assisted by a spinodal-decomposition nucleation process. Polymer films are widely used as substrates in nano-composite materials and therefore have to possess...

  18. Effect of film slicks on near-surface wind

    Science.gov (United States)

    Charnotskii, Mikhail; Ermakov, Stanislav; Ostrovsky, Lev; Shomina, Olga

    2016-09-01

    The transient effects of horizontal variation of sea-surface wave roughness due to surfactant films on near-surface turbulent wind are studied theoretically and experimentally. Here we suggest two practical schemes for calculating variations of wind velocity profiles near the water surface, the average short-wave roughness of which is varying in space and time when a film slick is present. The schemes are based on a generalized two-layer model of turbulent air flow over a rough surface and on the solution of the continuous model involving the equation for turbulent kinetic energy of the air flow. Wave tank studies of wind flow over wind waves in the presence of film slicks are described and compared with theory.

  19. Strain-Induced Water Dissociation on Supported Ultrathin Oxide Films

    CERN Document Server

    Song, Zhenjun; Xu, Hu

    2015-01-01

    Controlling the dissociation of single water molecule on an insulating surface plays a crucial role in many catalytic reactions. In this Letter, we have identified the enhanced chemical reactivity of ultrathin MgO(100) films deposited on Mo(100) substrate that causes water dissociation. We reveal that the ability to split water on insulating surface closely depends on the lattice mismatch between ultrathin films and the underlying substrate, and substrate-induced in-plane tensile strain dramatically results in water dissociation on MgO(100). Three dissociative adsorption configurations of water with lower energy are predicted, and the structural transition going from molecular form to dissociative form is almost barrierless. Our results provide an effective avenue to achieve water dissociation at the single-molecule level and shed light on how to tune the chemical reactions of insulating surfaces by choosing the suitable substrates.

  20. Water on graphene surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gordillo, M C [Departamento de Sistemas Fisicos, Quimicos y Naturales, Facultad de Ciencias Experimentales, Universidad Pablo de Olavide, Carretera de Utrera, km 1, E-41013 Sevilla (Spain); Marti, J, E-mail: cgorbar@upo.e, E-mail: jordi.marti@upc.ed [Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, B4-B5 Campus Nord, E-08034 Barcelona, Catalonia (Spain)

    2010-07-21

    In this paper, we summarize the main results obtained in our group about the behavior of water confined inside or close to different graphene surfaces by means of molecular dynamics simulations. These include the inside and outside of carbon nanotubes, and the confinement inside a slit pore or a single graphene sheet. We paid special attention to some thermodynamical (binding energies), structural (hydrogen-bond distributions) and dynamic (infrared spectra) properties, and their comparison to their bulk counterparts.

  1. Hydrophobicity of electron beam modified surface of hydroxyapatite films

    Energy Technology Data Exchange (ETDEWEB)

    Gregor, M., E-mail: gregor@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Plecenik, T. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Tofail, S.A.M. [Materials & Surface Science Institute, University of Limerick, Limerick (Ireland); Zahoran, M.; Truchly, M. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia); Vargova, M. [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, 84215 Bratislava (Slovakia); Laffir, F. [Materials & Surface Science Institute, University of Limerick, Limerick (Ireland); Plesch, G. [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, 84215 Bratislava (Slovakia); Kus, P.; Plecenik, A. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava (Slovakia)

    2015-05-15

    Highlights: • Surface potential of hydroxyapatite films were modified by focused electron beam. • Micron-sized domains of modified surface potential were created. • Wettability and surface free energy of the irradiated areas was studied. • Possible mechanisms of increased surface hydrophobicity are discussed. - Abstract: Arrays of micron-sized domains of modified surface potential were created on hydroxyapatite films by mid-energy (20 keV) electron beam irradiation available in a laboratory scanning electron microscope. The dosage of electron beam was varied between 10{sup −3} and 10{sup 3} μC/cm{sup 2} to inject charge into the film surface. Contrary to the conventional electrowetting theory, the dosage of injected charge used in creating such microdomains caused a gradual increase of the water contact angle from 57° to 93° due to the elimination of the polar component of the surface free energy. Surface contamination by carbonaceous species can be held only partially responsible for such behavior at lower dosage of electron beam. A transfer of free surface charge to water and an electron beam induced disruption of polar orientation of OH ions have been attributed to be influencial factors in the overall dewetting behavior.

  2. Solid surfaces, interfaces and thin films

    CERN Document Server

    Lüth, Hans

    2015-01-01

    This book emphasises both experimental and theoretical aspects of surface, interface and thin-film physics. As in previous editions the preparation of surfaces and thin films, their atomic and morphological structure, their vibronic and electronic properties as well as fundamentals of adsorption are treated. Because of their importance in modern information technology and nanostructure research, particular emphasis is paid to electronic surface and interface states, semiconductor space charge layers and heterostructures. A special chapter of the book is devoted to collective phenomena at interfaces and in thin films such as superconductivity and magnetism. The latter topic includes the meanwhile important issues giant magnetoresistance and spin-transfer torque mechanism, both effects being of high interest in information technology. In this new edition, for the first time, the effect of spin-orbit coupling on surface states is treated. In this context the class of the recently detected topological insulators,...

  3. Solid Surfaces, Interfaces and Thin Films

    CERN Document Server

    Lüth, Hans

    2010-01-01

    This book emphasises both experimental and theoretical aspects of surface, interface and thin film physics. As in previous editions the preparation of surfaces and thin films, their atomic and morphological, their vibronic and electronic properties as well as fundamentals of adsorption are treated. Because of their importance in modern information technology and nanostructure physics particular emphasis is paid to electronic surface and interface states, semiconductor space charge layers and heterostructures as well as to superconductor/semiconductor interfaces and magnetic thin films. The latter topic was significantly extended in this new edition by more details about the giant magnetoresistance and a section about the spin-transfer torque mechanism including one new problem as exercise. Two new panels about Kerr-effect and spin-polarized scanning tunnelling microscopy were added, too. Furthermore, the meanwhile important group III-nitride surfaces and high-k oxide/semiconductor interfaces are shortly discu...

  4. Physisorbed Films on Planar and Nonplanar Surfaces.

    Science.gov (United States)

    Cheng, E.

    1990-01-01

    In the case of multilayer liquid films on planar surfaces, we found that the widely used Frenkel-Halsey -Hill theory is the leading term of a many-body expansion of the more general Dzyaloshinskii-Lifshitz-Pitaevskii theory in the nonretardation limit. While the FHH theory is a good approximation in the thin film region, retardation has been shown to be important at thickness d >=q 100 A. A universal behavior of the retardation has also been found. Submonolayer He film on weak-binding substrate surfaces have been found to have unexpected and exciting new features. The weak binding of the substrate potential supports only low density monolayer He films so that the monolayer He solid can be eliminated. Meanwhile, the z -wise delocalization of He atoms reduces the He-He interaction and the lateral binding. It is possible that the 2D liquid film will be eliminated as well and a quasi-2D bose gas is expected. A further possibility is that no He monolayer film at all will be present on a weak-binding substrate. The possibility of using the fractal geometry to describe (global) surface roughness has been investigated. A power-law relation between the coverage and thickness is found on a fractally rough surface, with its exponent determined by the surface fractal dimension. A new and interesting phenomenon has been found: the adsorbed film "defractalizes" the substrate surface; this is observable by small angle x-ray and neutron scattering measurements. Adsorption inside a cylindrical pore and near an oblique corner have also been discussed.

  5. Polymer surfaces, interfaces and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, M. [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany)

    1996-11-01

    Neutron reflectometry can be used in various ways to investigate surfaces, interfaces and thin films of polymers. Its potential comes mostly from the possibilities offered by selective deuteration, where a particular component can be made visible with respect to its activity at the interface. In addition the depth resolution is much better than with most other direct techniques, and details of the profiles may be resolved. Several examples will be discussed including the segment diffusion at the interface between two polymer films, the determination of the narrow interfaces between incompatible polymer blends and the development of order in thin diblock copolymer films. (author) 10 figs., 2 tabs., 38 refs.

  6. Dynamic behavior of the water droplet impact on a textured hydrophobic/superhydrophobic surface: the effect of the remaining liquid film arising on the pillars' tops on the contact time.

    Science.gov (United States)

    Li, Xiying; Ma, Xuehu; Lan, Zhong

    2010-04-06

    We have fabricated a series of textured silicon surfaces decorated by square arrays of pillars whose radius and pitch can be adjusted independently. These surfaces possessed a hydrophobic/superhydrophobic property after silanization. The dynamic behavior of water droplets impacting these structured surfaces was examined using a high-speed camera. Experimental results validated that the remaining liquid film on the pillars' tops gave rise to a wet surface instead of a dry surface as the water droplet began to recede away from the textured surfaces. Also, experimental results demonstrated that the difference in the contact time was subjected to the solid fraction referred to as the ratio of the actual area contacting with the liquid to its projected area on the textured surface. Because the mechanism by which the residual liquid film emerges on the pillars' tops can essentially be ascribed to the pinch-off of the liquid threads, we further addressed the changes in the contact time in terms of the characteristic time of pinch-off of an imaginary liquid cylinder whose radius is related to the solid fraction and the maximum contact area. The match of the theoretical analysis and the experimental results substantiates the assumption aforementioned.

  7. Film cooling enhancement with surface restructure

    Science.gov (United States)

    Chen, Shuping

    Discrete-hole film cooling is used extensively in turbine components. In past decades, many research works concerning this technique have been published. Recently, efforts have been directed at seeking technologies that would increase film cooling effectiveness. Particularly, surface reshaping through protective coatings, such as a thermal barrier coating (TBC), is very attractive to turbine designers because extra machining work is not needed for its application. In the present work, film cooling enhancement with surface restructure is experimentally studied using an infrared (IR) imaging technique. The first surface structure studied is the surface with flow-aligned blockers. The studied configurations include single-hole and three-hole-row structures. The single-hole case is used for studying the effects of blocker design parameters, which include blocker height (0.2D, 0.4D, and 0.6D), distance between two neighboring blockers (0.8D, D, and 1.2D), blocker length (2", 4", and 6"), and blowing ratio M (0.43 and 0.93). The design with the best performance is chosen for the three-hole-row cases. The second surface shape studied, is the so-called upstream ramp, which is placed in front of a row of film cooling holes. Investigated geometrical parameters include upstream ramp angles (8.5°, 15°, and 24°) and blowing ratio M (0.29, 0.43, 0.57, 0.93, and 1.36). Detailed local film cooling effectiveness and heat transfer coefficient are measured using an IR imaging technique. The third film cooling concept is the so-called trenched film cooling holes, i.e., film cooling holes sitting in a transverse groove. The film cooling structure for this experimental test consists of a three-hole row embedded in a trench 0.5D in depth and 2D in width, where D is the diameter of the holes. Five blowing ratios (0.29, 0.43, 0.57, 0.93, and 1.36) are tested. Based on the tested results, the three film cooling schemes are also compared. To implement the experimental work, a test system

  8. Thin film surface reconstruction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Imperatori, P. [CNR, Monterotondo Stazione, Rome (Italy). Istituto di Chimica dei materiali

    1996-09-01

    The study of the atomic structure of surfaces and interfaces is a fundamental step in the knowledge and the development of new materials. Among the several surface-sensitive techniques employed to characterise the atomic arrangements, grazing incidence x-ray diffraction (GIXD) is one of the most powerful. With a simple data treatment, based on the kinematical theory, and using the classical methods of x-ray bulk structure determination, it gives the atomic positions of atoms at a surface or an interface and the atomic displacements of subsurface layers for a complete determination of the structure. In this paper the main features of the technique will be briefly reviewed and selected of application to semiconductor and metal surfaces will be discussed.

  9. Surface Chemistry Interactions of Cationorm with Films by Human Meibum and Tear Film Compounds

    Directory of Open Access Journals (Sweden)

    Georgi As. Georgiev

    2017-07-01

    Full Text Available Cationorm® (CN cationic nanoemulsion was demonstrated to enhance tear film (TF stability in vivo possibly via effects on tear film lipid layer (TFLL. Therefore the interactions of CN with human meibum (MGS and TFLL in vitro and in vivo deserve special study. MGS and CN were spread at the air/water interface of a Langmuir surface balance to ensure a range of MGS/CN oil phase ratios: 20/1, 10/1, 5/1, 3/1, 2/1 and 1/1. The films capability to reorganize during dynamic area changes was evaluated via the surface pressure-area compression isotherms and step/relaxation dilatational rheology studies. Films structure was monitored with Brewster angle microscopy. CN/TFLL interactions at the ocular surface were monitored with non-contact specular microscopy. The in vitro studies of MGS/CN layers showed that (i CN inclusion (at fixed MGS content increased film elasticity and thickness and that (ii CN can compensate for moderate meibum deficiency in MGS/CN films. In vivo CN mixed with TFLL in a manner similar to CN/MGS interactions in vitro, and resulted in enhanced thickness of TFLL. In vitro and in vivo data complement each other and facilitated the study of the composition-structure-function relationship that determines the impact of cationic nanoemulsions on TF.

  10. Surface morphology of thin films polyoxadiazoles

    OpenAIRE

    J. Weszka; M.M. Szindler; M. Chwastek-Ogierman; BRUMA M.; P. Jarka; Tomiczek, B.

    2011-01-01

    urpose: The purpose of this paper was to analyse the surface morphology of thin films polyoxadiazoles. Design/methodology/approach: SSix different polymers which belong to the group of polyoxadiazoles were dissolved in the solvent NMP. Each of these polymer was deposited on a glass substrate and a spin coating method was applied with a spin speed of 1000, 2000 and 3000 rev/min. Changes in surface topography and roughness were observed. An atomic force microscope AFM Park System has been used....

  11. Ion Diffusion Within Water Films in Unsaturated Porous Media.

    Science.gov (United States)

    Tokunaga, Tetsu K; Finsterle, Stefan; Kim, Yongman; Wan, Jiamin; Lanzirotti, Antonio; Newville, Matthew

    2017-04-05

    Diffusion is important in controlling local solute transport and reactions in unsaturated soils and geologic formations. Although it is commonly assumed that thinning of water films controls solute diffusion at low water contents, transport under these conditions is not well understood. We conducted experiments in quartz sands at low volumetric water contents (θ) to quantify ion diffusion within adsorbed films. At the lowest water contents, we employed fixed relative humidities to control water films at nm thicknesses. Diffusion profiles for Rb(+) and Br(-) in unsaturated sand packs were measured with a synchrotron X-ray microprobe, and inverse modeling was used to determine effective diffusion coefficients, De, as low as ∼9 × 10(-15) m(2) s(-1) at θ = 1.0 × 10(-4) m(3) m(-3), where the film thickness = 0.9 nm. Given that the diffusion coefficients (Do) of Rb(+) and Br(-) in bulk water (30 °C) are both ∼2.4 × 10(-9) m(2) s(-1), we found the impedance factor f = De/(θDo) is equal to 0.03 ± 0.02 at this very low saturation, in agreement with the predicted influence of interface tortuosity (τa) for diffusion along grain surfaces. Thus, reduced cross-sectional area (θ) and tortuosity largely accounted for the more than 5 orders of magnitude decrease in De relative to Do as desaturation progressed down to nanoscale films.

  12. Current-induced surface roughness reduction in conducting thin films

    Science.gov (United States)

    Du, Lin; Maroudas, Dimitrios

    2017-03-01

    Thin film surface roughness is responsible for various materials reliability problems in microelectronics and nanofabrication technologies, which requires the development of surface roughness reduction strategies. Toward this end, we report modeling results that establish the electrical surface treatment of conducting thin films as a physical processing strategy for surface roughness reduction. We develop a continuum model of surface morphological evolution that accounts for the residual stress in the film, surface diffusional anisotropy and film texture, film's wetting of the layer that is deposited on, and surface electromigration. Supported by linear stability theory, self-consistent dynamical simulations based on the model demonstrate that the action over several hours of a sufficiently strong and properly directed electric field on a conducting thin film can reduce its surface roughness and lead to a smooth planar film surface. The modeling predictions are in agreement with experimental measurements on copper thin films deposited on silicon nitride layers.

  13. Piezoelectric Film Waveguides for Surface Acoustic Waves

    Directory of Open Access Journals (Sweden)

    M.F. Zhovnir

    2016-11-01

    Full Text Available The paper presents results of mathematical modeling of piezoelectric film waveguide structures for surface acoustic waves (SAW. Piezoelectric ZnO film is supposed to be placed on a fused quartz substrate. The analytical ratios and numerical results allow to determine the design parameters of the waveguide structures to provide a single-mode SAW propagation mode. The results of amplitude and phase experimental studies of the SAW in the waveguide structures that were carried out on the laser optical sensing set up confirm the theoretical calculations.

  14. Surface functionalization by fine ultraviolet-patterning of nanometer-thick liquid lubricant films

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Renguo [Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Zhang, Hedong, E-mail: zhang@is.nagoya-u.ac.jp [Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Komada, Suguru [Department of Micro-Nano System Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Mitsuya, Yasunaga [Nagoya Industrial Science Research Institute, Noa Yotsuya Building 2F, 1-13, Yotsuya-Douri, Chikusa-ku, Nagoya 464-0819 (Japan); Fukuzawa, Kenji; Itoh, Shintaro [Department of Micro-Nano System Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2014-11-30

    Highlights: • We present fine UV-patterning of nm-thick liquid films for surface functionalization. • The patterned films exhibit both a morphological pattern and a functional pattern of different surface properties. • The finest pattern linewidth was 0.5 μm. • Fine patterning is crucial for improving surface and tribological properties. - Abstract: For micro/nanoscale devices, surface functionalization is essential to achieve function and performance superior to those that originate from the inherent bulk material properties. As a method of surface functionalization, we dip-coated nanometer-thick liquid lubricant films onto solid surfaces and then patterned the lubricant films with ultraviolet (UV) irradiation through a photomask. Surface topography, adhesion, and friction measurements demonstrated that the patterned films feature a concave–convex thickness distribution with thicker lubricant in the irradiated regions and a functional distribution with lower adhesion and friction in the irradiated convex regions. The pattern linewidth ranged from 100 to as fine as 0.5 μm. The surface functionalization effect of UV-patterning was investigated by measuring the water contact angles, surface energies, friction forces, and depletion of the patterned, as-dipped, and full UV-irradiated lubricant films. The full UV-irradiated lubricant film was hydrophobic with a water contact angle of 102.1°, and had lower surface energy, friction, and depletion than the as-dipped film, which was hydrophilic with a water contact angle of 80.7°. This demonstrates that UV irradiation substantially improves the surface and tribological properties of the nanometer-thick liquid lubricant films. The UV-patterned lubricant films exhibited superior surface and tribological properties than the as-dipped film. The water contact angle increased and the surface energy, friction, and depletion decreased as the pattern linewidth decreased. In particular, the 0.5-μm patterned lubricant

  15. Surface roughness and chemical properties of porous inorganic films

    Energy Technology Data Exchange (ETDEWEB)

    Eggen, Carrie L.; McAfee, Paul M. [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287 (United States); Jin, Yi [China Electric Power Research Institute, Beijing 100192 (China); Lin, Y.S., E-mail: jerry.lin@asu.edu [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287 (United States)

    2015-09-30

    Porous inorganic films of different materials and pore architecture: mesoporous γ-alumina, mesoporous yttria stabilized zirconia (YSZ), macroporous YSZ and macroporous/microporous zeolite silicalite, were synthesized by the sol–gel spin-coating or dip-coating methods on silicon wafers of different surface roughness. Their surface chemical properties, pore and phase structure, and surface roughness were studied by various surface characterization methods. The pore sizes of these films are determined by their primary particle size. All the films studied are hydrophilic due to the presence of hydroxyl groups on the external crystallite surface, and their hydrophilicity increases in the order: macroporous YSZ < mesoporous YSZ < silicalite < γ-alumina. The γ-alumina films have highly smooth surfaces, while mesoporous YSZ, macroporous YSZ and silicalite films have similar surface roughness much rougher than γ-alumina films. The surface roughness of these coated films does not depend on the coating method, surface roughness of the substrate, surface chemistry or pore structure of the films. It is more controlled by the shape and size of the primary particles and aggregates in the sol or suspension from which the films are obtained. - Highlights: • Porous films of various pore structures are prepared by sol–gel methods. • γ-Alumina films have much smoother surface than thin films of other materials. • Film surface roughness is controlled by the shape and size of particles in the sols.

  16. Modeling surface imperfections in thin films and nanostructured surfaces

    DEFF Research Database (Denmark)

    Hansen, Poul-Erik; Madsen, J. S.; Jensen, S. A.

    2017-01-01

    Accurate scatterometry and ellipsometry characterization of non-perfect thin films and nanostructured surfaces are challenging. Imperfections like surface roughness make the associated modelling and inverse problem solution difficult due to the lack of knowledge about the imperfection on the surf......Accurate scatterometry and ellipsometry characterization of non-perfect thin films and nanostructured surfaces are challenging. Imperfections like surface roughness make the associated modelling and inverse problem solution difficult due to the lack of knowledge about the imperfection...... classes of imperfections are examined. The imperfections are introduced as periodic structures with a super cell periods ten times larger than the simple grating period. Two classes of imperfections concern the grating and one class concern the substrate. It is shown that imperfections of a few nanometers...

  17. Photoemission surface characterization of (0 0 1) In{sub 2}O{sub 3} thin film through the interactions with oxygen, water and carbon monoxide: Comparison with (1 1 1) orientation

    Energy Technology Data Exchange (ETDEWEB)

    Brinzari, V., E-mail: vbrinzari@mail.ru [State University of Moldova, str. Mateevich 60A, MD-2009 Chisinau, Republic of Moldova (Moldova, Republic of); Cho, B.K. [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Kamei, M. [National Institute for Material Science, Namiki, Tsukuba, Ibaraki (Japan); Korotcenkov, G., E-mail: ghkoro@yahoo.com [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

    2015-01-01

    Highlights: • SRPES of In{sub 2}O{sub 3}(0 0 1) thin film under heating activated gas exposures of O{sub 2}, H{sub 2}O, CO. • Changes in surface band bending and composition vs. these treatments. • Models of (0 0 1) surface terminations, compositions and zone diagrams. • Changes in VB spectra radically differ from the same ones for (1 1 1) film. • Adsorbed water species do not donate electrons into conduction band. - Abstract: Synchrotron radiation ultraviolet photoemission experiments at photon energies of 150 and 49 eV have been performed on (0 0 1) In{sub 2}O{sub 3} epitaxial layer with thickness of 120 nm grown by electron beam evaporation method. Valence band (VB) photoemission spectra have been monitored under separate oxygen, water and carbon monoxide exposures (100 L) at different sample temperatures within the range utilized for chemoresistive gas sensors operation (20–450 °C). Large changes in photoemission response within the whole VB were observed for all gases. Surface potential changes were identified as a shift of the valence band edge relative to the Fermi energy. It was found that the initial state of the In{sub 2}O{sub 3} surface after standard preparation procedure corresponded to highly reduced surface, close to “metallic” surface. Treatments in oxygen resulted in oxidation of the surface and regular upward band bending have been changing up to 0.27 eV. These two extreme states of the In{sub 2}O{sub 3} surface corresponded to the surface zone diagrams with accumulation layer and flat bands, respectively. Surface potential changes under water and carbon monoxide treatment have been irregular vs. temperature and small enough (<0.05 eV). However, the magnitudes of photoemission deviations under these treatments were large and comparable with intensity of an initial photoemission itself before the treatment (ΔI{sub ph} ∼ 10–40%). The obtained results have been compared with the ones previously received for (1 1 1) surface and

  18. Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

    OpenAIRE

    Rackel Reis; Dumée, Ludovic F.; Tardy, Blaise L.; Raymond Dagastine; John D. Orbell; Jürg A. Schutz; Duke, Mikel C.

    2016-01-01

    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membra...

  19. Sustaining dry surfaces under water

    DEFF Research Database (Denmark)

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.

    2015-01-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional...... mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have...... not been investigated, and are critically important to maintain surfaces dry under water.In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical...

  20. Sustaining dry surfaces under water

    Science.gov (United States)

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-08-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys - thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments.

  1. Surface plasmons in porous gold films

    Science.gov (United States)

    Rudenko, S. P.; Stetsenko, M. O.; Krishchenko, I. M.; Maksimenko, L. S.; Kaganovich, E. B.; Serdega, B. K.

    2016-04-01

    The surface plasmon resonance effects in porous gold (por-Au) films—nanocomposite porous films containing an ensemble of disordered gold nanoparticles—have been investigated by modulation-polarization spectroscopy. Por-Au films have been obtained by pulsed laser deposition (using a direct particle flow from an erosion torch formed by a YAG:Nd3+ laser in argon). The spectral and angular dependences of the polarization difference ρ(λ, θ) of internal-reflection coefficients of s- and p-polarized radiation in the Kretschmann geometry and the spectral dependences of isotropic reflection angles at ρ(θ) = 0 are measured. Two types of surface plasmon resonance are found: one occurs on isolated nanoparticles (dipole and multipole modes), and the other is due to the dipole-dipole interaction of neighboring nanoparticles. The frequency of electron plasma oscillations for the nanoparticle ensemble and the frequencies and decay parameters of resonances are determined. Dispersion relations for the radiative and nonradiative modes are presented. The negative sign of the dispersion branch of nonradiative modes of dipole-dipole interaction is explained by the spatial dispersion of permittivity. The relationships between the formation conditions of the films, their structure, and established resonance parameters (determining the resonant-optical properties of films) are discussed.

  2. Superhydrophobic films on glass surface derived from trimethylsilanized silica gel nanoparticles.

    Science.gov (United States)

    Goswami, Debmita; Medda, Samar Kumar; De, Goutam

    2011-09-01

    The paper deals with the fabrication of sol-gel-derived superhydrophobic films on glass based on the macroscopic silica network with surface modification. The fabricated transparent films were composed of a hybrid -Si(CH(3))(3)-functionalized SiO(2) nanospheres exhibiting the desired micro/nanostructure, water repellency, and antireflection (AR) property. The wavelength selective AR property can be tuned by controlling the physical thickness of the films. Small-angle X-ray scattering (SAXS) studies revealed the existence of SiO(2) nanoparticles of average size ∼9.4 nm in the sols. TEM studies showed presence of interconnected SiO(2) NPs of ∼10 nm in size. The films were formed with uniformly packed SiO(2) aggregates as observed by FESEM of film surface. FTIR of the films confirmed presence of glasslike Si-O-Si bonding and methyl functionalization. The hydrophobicity of the surface was depended on the thickness of the deposited films. A critical film thickness (>115 nm) was necessary to obtain the air push effect for superhydrophobicity. Trimethylsilyl functionalization of SiO(2) and the surface roughness (rms ≈30 nm as observed by AFM) of the films were also contributed toward the high water contact angle (WCA). The coated glass surface showed WCA value of the droplet as high as 168 ± 3° with 6 μL of water. These superhydrophobic films were found to be stable up to about 230-240 °C as confirmed by TG/DTA studies, and WCA measurements of the films with respect to the heat-treatment temperatures. These high water repellant films can be deposited on relatively large glass surfaces to remove water droplets immediately without any mechanical assistance.

  3. Surface properties of latex film and solvent-borne film resulted from fluorinated acrylate copolymers prepared by emulsion polymerization

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available The fluorinated acrylate copolymer, poly (BMA-co-DFHMA, was prepared by emulsion polymerization using a preemulsified monomer addition process. The FTIR and 1H –NMR were used to characterize the copolymer structure. The contact angle of water on the solvent-borne film increased dramatically and reached an equilibrium value (103° when the PDFHMA content in the copolymer was only 0.97 mol%. However, the contact of water on the latex film increased slowly, and reached the equilibrium value of 99° until the fluorinated component content was as highly as 9 mol%. A similar result was observed for the oil contact angle on the two types of films. XPS results showed that when the F/C ratio on film surfaces reached equilibrium, the required content of fluorinated component in the copolymer for the solvent-borne film was much lower than that for the latex film.

  4. Artificial Ground Water Recharge with Surface Water

    Science.gov (United States)

    Heviánková, Silvie; Marschalko, Marian; Chromíková, Jitka; Kyncl, Miroslav; Korabík, Michal

    2016-10-01

    With regard to the adverse manifestations of the recent climatic conditions, Europe as well as the world have been facing the problem of dry periods that reduce the possibility of drawing drinking water from the underground sources. The paper aims to describe artificial ground water recharge (infiltration) that may be used to restock underground sources with surface water from natural streams. Among many conditions, it aims to specify the boundary and operational conditions of the individual aspects of the artificial ground water recharge technology. The principle of artificial infiltration lies in the design of a technical system, by means of which it is possible to conduct surplus water from one place (in this case a natural stream) into another place (an infiltration basin in this case). This way, the water begins to infiltrate into the underground resources of drinking water, while the mixed water composition corresponds to the water parameters required for drinking water.

  5. The glass-liquid transition of water on hydrophobic surfaces.

    Science.gov (United States)

    Souda, Ryutaro

    2008-09-28

    Interactions of thin water films with surfaces of graphite and vitrified room-temperature ionic liquid [1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)])] were investigated using time-of-flight secondary ion mass spectrometry as a function of temperature and annealing time to elucidate the glass-liquid transition of water at the molecular level. Surface diffusion of water occurs at temperatures higher than 120 K, thereby forming three-dimensional clusters (a two-dimensional layer) on the [bmim][PF(6)] (graphite) surface. The hydrophobic effect of the surface decreases with increasing coverage of water; the bulklike properties evolve up to 40 ML, as evidenced by the occurrence of film dewetting at around the conventional glass transition temperature (140 K). Results also showed that aging is necessary for the water monolayer (a 40 ML water film) to dewet the graphite ([bmim][PF(6)]) surface. The occurrence of aging is explainable by the successive evolution of two distinct liquids during the glass-liquid transition: low density liquid is followed by supercooled liquid water. The water monolayer on graphite is characterized by the preferred orientation of unpaired OH groups toward the surface; this structure is arrested during the aging time despite the occurrence of surface diffusion. However, the water monolayer formed on the [bmim][PF(6)] surface agglomerates immediately after the commencement of surface diffusion. The structure of low density liquid tends to be arrested by the attractive interaction with the neighbors.

  6. Grafting of PEG400 onto the surface of LLDPE/SMA film

    Institute of Scientific and Technical Information of China (English)

    CHEN Gufeng; ZHANG Yi; ZHU Yafei; XU Jiarui

    2007-01-01

    Linear low-density polyethylene (LLDPE)was melt and blended with styrene-maleic anhydride copolymer (SMA).The blending films were then immersed in poly(ethylene glycol)400 (PEG400) at room temperature.The surface composition of the blend films was determined by Fourier transform infra-red spectroscopy coupled with a variable incidence angle attenuated total reflection accessory (ATR-FTIR).Results show that PEG400 can be grafted onto the surface of the films via esterification with SMA.The immersion of PEG promotes the enrichment of SMA onto the surface of the films.The water contact angle data show that grafting of PEG400 onto PE can greatly improve the hydrophilicity of the PE surface.These experiments show that surface functionalization of polyethylene films by blending SMA and then surface grafting of PEG is feasible,which suggest an effective and simple route for PE surface modification via blending and grafting.

  7. Simultaneous measurements of top surface and its underlying film surfaces in multilayer film structure.

    Science.gov (United States)

    Ghim, Young-Sik; Rhee, Hyug-Gyo; Davies, Angela

    2017-09-19

    With the growth of 3D packaging technology and the development of flexible, transparent electrodes, the use of multilayer thin-films is steadily increasing throughout high-tech industries including semiconductor, flat panel display, and solar photovoltaic industries. Also, this in turn leads to an increase in industrial demands for inspection of internal analysis. However, there still remain many technical limitations to overcome for measurement of the internal structure of the specimen without damage. In this paper, we propose an innovative optical inspection technique for simultaneous measurements of the surface and film thickness corresponding to each layer of multilayer film structures by computing the phase and reflectance over a wide range of wavelengths. For verification of our proposed method, the sample specimen of multilayer films was fabricated via photolithography process, and the surface profile and film thickness of each layer were measured by two different techniques of a stylus profilometer and an ellipsometer, respectively. Comparison results shows that our proposed technique enables simultaneous measurements of the top surface and its underlying film surfaces with high precision, which could not be measured by conventional non-destructive methods.

  8. Uptake of Water Onto Organic Films Containing Oxidized Functional Groups

    Science.gov (United States)

    Demou, E.; Donaldson, D. J.

    There is increasing evidence that atmospheric particles may contain significant mass fractions of organic compounds. Such particles may be predominantly organic (as in SOA condensates) or may have mixed aqueous-organic character. In either case, the particle surface exposed to the atmosphere, if it has organic character, is subject to oxidation by OH, O3 and NO3 gas phase molecules. Surface oxidation is expected to alter the hydrophobic nature of an organic surface layer, and thus perhaps facilitate the particle's ability to act as a cloud condensation nucleus. We have used a quartz crystal microbalance (QCM) to measure the mass uptake of water by organic films as a func- tion of the ambient relative humidity. Results for the room-temperature condensation of water onto films composed of aliphatic hydrocarbons, mono- and di-alcohols and mono- and di-acids will be presented.

  9. The structure and surface energy of Ni{sub 80}Fe{sub 20} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yuan-Tsung, E-mail: ytchen@yuntech.edu.tw; Chen, Chin-Wu; Wu, Te-Ho

    2015-10-01

    Highlights: • X-ray diffraction patterns indicated NiFe thin films exhibited a face-centred cubic (FCC) structural. • NiFe films were more crystalline after postannealing treatment than they were after RT treatment. • NiFe films formed a contact angle of <90°, which indicated that the NiFe films were hydrophilic. • The surface energy was associated with the crystallinity of the thin films. • NiFe thin films exhibit low surface-energy characteristics that can produce a self-cleaning effect. - Abstract: In this study, NiFe thin films were deposited on a glass substrate at room temperature (RT) or postannealed at 150 and 250 °C for 1 h; the Ni{sub 80}Fe{sub 20} films were 300–1500 Å thick. The structure, surface energy, and average contact angle properties of the NiFe thin films were investigated. X-ray diffraction (XRD) results demonstrated that the NiFe thin films exhibited a face-centred cubic (FCC) structural state. The XRD results also revealed that the NiFe films were more crystalline after post-annealing treatment than they were after RT treatment alone, suggesting that the NiFe crystalline structure exhibited FCC (1 1 1) texturing. The NiFe films formed a contact angle of <90° with the test liquids water and diiodomethane, which indicated that the NiFe films were hydrophilic. The surface energy of the NiFe thin films decreased when post-annealing treatment was used and their thickness was increased from 60.4 to 47.9 mJ/mm{sup 2}, suggesting that the surface energy was associated with the crystallinity of the thin films. Therefore, these NiFe thin films exhibit low surface-energy characteristics that can produce a self-cleaning effect.

  10. Fabrication of a super-hydrophobic nanofibrous zinc oxide film surface by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Ding Bin [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Fiber and Polymer Science, University of California, Davis, CA 95616 (United States)], E-mail: bding@ucdavis.edu; Ogawa, Tasuku [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Kim, Jinho [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); SNT Ltd, Kawasaki 212-0054 (Japan); Fujimoto, Kouji [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Shiratori, Seimei [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); SNT Ltd, Kawasaki 212-0054 (Japan)], E-mail: shiratori@appi.keio.ac.jp

    2008-03-03

    We report a new approach for fabricating a super-hydrophobic nanofibrous zinc oxide (ZnO) film surface. The pure poly(vinyl alcohol) (PVA) and composite PVA/ZnO nanofibrous films can be obtained by electrospinning the PVA and PVA/zinc acetate solutions, respectively. After the calcination of composite fibrous films, the inorganic fibrous ZnO films with a reduced fiber diameter were fabricated. The wettability of three kinds of fibrous film surfaces were modified with a simple coating of fluoroalkylsilane (FAS) in hexane. The resultant samples were characterized by field emission scanning electron microscopy (FE-SEM), water contact angle (WCA), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). It was found that the pure PVA fibrous films maintained the super-hydrophilic surface property even after the FAS modification. Additionally, the WCA of composite fibrous films was increased from 105 to 132 deg. with the coating of FAS. Furthermore, the surface property of inorganic ZnO fibrous films was converted from super-hydrophilic (WCA of 0 deg.) to super-hydrophobic (WCA of 165{sup o}) after the surface modification with FAS. Observed from XPS data, the hydrophobicity of FAS coated various film surfaces were found to be strongly affected by the ratio of fluoro:oxygen on the film surfaces.

  11. Water droplet behavior on superhydrophobic SiO2 nanocomposite films during icing/deicing cycles

    NARCIS (Netherlands)

    Lazauskas, A.; Guobiene, A.; Prosycevas, I.; Baltrusaitis, V.; Grigaliunas, V.; Narmontas, P.; Baltrusaitis, Jonas

    2013-01-01

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, wat

  12. Water droplet behavior on superhydrophobic SiO2 nanocomposite films during icing/deicing cycles

    NARCIS (Netherlands)

    Lazauskas, A.; Guobiene, A.; Prosycevas, I.; Baltrusaitis, V.; Grigaliunas, V.; Narmontas, P.; Baltrusaitis, J.

    2013-01-01

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, wat

  13. Water droplet behavior on superhydrophobic SiO2 nanocomposite films during icing/deicing cycles

    NARCIS (Netherlands)

    Lazauskas, A.; Guobiene, A.; Prosycevas, I.; Baltrusaitis, V.; Grigaliunas, V.; Narmontas, P.; Baltrusaitis, Jonas

    2013-01-01

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment,

  14. Adsorptive properties of natural water surfactant films. Dead Vistula catchment water studies

    Directory of Open Access Journals (Sweden)

    Stanisław J. Pogorzelski

    2003-09-01

    Full Text Available The paper contains the results of natural film experiments carried out on inland waters in the Dead Vistula (Martwa Wisła catchment area during 1999-2002 using the integrated Langmuir trough-Wilhelmy plate system, which "cuts out" an undisturbed film-covered area without any physicochemical sample processing. The static film parameters result from the generalized scaling procedures applied to the surface pressure-area isotherms. They appear to correspond well to observations of the film composition Alim, MW, Eisoth, film solubility and the miscibility of its components (via R, ΔSc and y factors, and surface concentration Πeq, Γeq. A novel approach is presented for the adsorption dynamics on the basis of the mixed kinetic-diffusion model and analyses of the dynamic surface pressure plots, which leads to the determination of the effective relative diffusion coefficient Deff / D and activation energy barrier i>Ea / RT. There is reason to believe that certain classes of film-forming components or "end-members" may dominate the static and dynamic surface properties. Some of these substances can be used as source-specific surface-active biomarkers to trace temporal and spatial changes due to environmental factors or the production of biological matter. The concept was tested for the Dead Vistula river and its tributaries. The results demonstrate that natural films are a complex mixture of biopolymeric molecules covering a wide range of solubilities, surface activities and molecular masses with an apparentstructural film architecture. Such studies could lead to the development of film structure parameters - indicators of ecosystem quality and the state of the environment.

  15. Nematic films at chemically structured surfaces

    Science.gov (United States)

    Silvestre, N. M.; Telo da Gama, M. M.; Tasinkevych, M.

    2017-02-01

    We investigate theoretically the morphology of a thin nematic film adsorbed at flat substrate patterned by stripes with alternating aligning properties, normal and tangential respectively. We construct a simple ‘exactly-solvable’ effective interfacial model where the liquid crystal distortions are accounted for via an effective interface potential. We find that chemically patterned substrates can strongly deform the nematic-air interface. The amplitude of this substrate-induced undulations increases with decreasing average film thickness and with increasing surface pattern pitch. We find a regime where the interfacial deformation may be described in terms of a material-independent universal scaling function. Surprisingly, the predictions of the effective interfacial model agree semi-quantitatively with the results of the numerical solution of a full model based on the Landau-de Gennes theory coupled to a square-gradient phase field free energy functional for a two phase system.

  16. Surface structure of coherently strained ceria ultrathin films

    Science.gov (United States)

    Shi, Yezhou; Stone, Kevin H.; Guan, Zixuan; Monti, Matteo; Cao, Chuntian; El Gabaly, Farid; Chueh, William C.; Toney, Michael F.

    2016-11-01

    Cerium oxide, or ceria, is an important material for solid oxide fuel cells and water splitting devices. Although the ceria surface is active in catalytic and electrochemical reactions, how its catalytic properties are affected by the surface structure under operating conditions is far from understood. We investigate the structure of the coherently strained Ce O2 ultrathin films on yttria-stabilized zirconia (001) single crystals by specular synchrotron x-ray diffraction (XRD) under oxidizing conditions as a first step to study the surface structure in situ. An excellent agreement between the experiment data and the model is achieved by using a "stacks and islands" model that has a two-component roughness. One component is due to the tiny clusters of nanometer scale in lateral dimensions on each terrace, while the other component is due to slightly different Ce O2 thickness that span over hundreds of nanometers on neighboring terraces. We attribute the nonuniform thickness to step depairing during the thin film deposition that is supported by the surface morphology results on the microscopic level. Importantly, our model also shows that the polarity of the ceria surface is removed by a half monolayer surface coverage of oxygen. The successful resolution of the ceria surface structure using in situ specular synchrotron XRD paves the way to study the structural evolution of ceria as a fuel cell electrode under catalytically relevant temperatures and gas pressures.

  17. Aqueous phase deposition of dense tin oxide films with nano-structured surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Yoshitake, E-mail: masuda-y@aist.go.jp; Ohji, Tatsuki; Kato, Kazumi

    2014-06-01

    Dense tin oxide films were successfully fabricated in an aqueous solution. The pH of the solutions was controlled to pH 1.3 by addition of HCl. Precise control of solution condition and crystal growth allowed us to obtain dense tin oxide films. Concave–convex surface of fluorine-doped tin oxide (FTO) substrates was entirely-covered with the continuous films. The films were about 65 nm in thickness and had nano-structured surfaces. Morphology of the films was strikingly different from our previous reported nano-sheet assembled structures. The films were not removed from the substrates by strong water flow or air blow to show strong adhesion strength. The aqueous solution process can be applied to surface coating of various materials such as nano/micro-structured surfaces, particles, fibers, polymers, metals or biomaterials. - Graphical abstract: Dense tin oxide films of 65 nm were successfully fabricated in an aqueous solution. They had nano-structured surfaces. Concave-convex substrates were entirely-covered with the continuous films. - Highlights: • Dense tin oxide films of 65 nm were successfully fabricated in an aqueous solution. • They had nano-structured surfaces. • Concave–convex substrates were entirely-covered with the continuous films.

  18. Surface characterization of Laponite-Poly(ethylene oxide) nanocomposite films

    Science.gov (United States)

    Stefanescu, Eduard A.; Negulescu, Ioan I.; Daly, William H.; Donose, Bogdan C.; Nguyen, Anh V.

    2008-03-01

    The aim of the present work is to understand how ionic strength of precursor polymer-clay gels influences the final structure of multilayered nanocomposite films fabricated from such gels. We have prepared three aqueous precursor gels containing 3wt% LRD, 2wt% PEO and 95wt% water, in which the salt concentrations were kept at 0X, 1X and 3X with X = 5.57 * 10^- 5 g NaCl/mL. The Laponite (LRD) - PEO multilayered films (LRD60%-PEO40%) were fabricated by manually spreading and drying each gel on a glass slide. Prior to the AFM measurements the polymer-clay composite films where freeze-dried by immersion in liquid nitrogen until they were totally degassed. Frozen samples where then fractured and left for additional drying for 24 hours in a desiccator. The imaging procedure employed here was tapping-mode AFM. Distinct features were identified on the layered transversal surface of the films, and were attributed to the different salt concentrations in the samples. Addition of salt increases the adhesion and compactness properties of the nanoparticles, as a more uniform side surface can be observed after freeze-fracturing the materials.

  19. Static and dynamic properties of surfactant films on natural waters

    Directory of Open Access Journals (Sweden)

    Stanis³aw J. Pogorzelski

    2001-06-01

    Full Text Available The paper contains the results of natural surface film surface pressure - area experiments carried out in inland waters and shallow offshore regions of the Baltic and Mediterranean Seas during 1990-99 under calm water conditions using the Langmuir trough - Wilhelmy filter paper plate system, which "cuts out" an undisturbed film-covered sea area without any initial physico-chemical sample processing. The limiting specific area Alim (268–3157 Å2/molecule-1 and mean molecular mass (0.65-9.7 kDa of microlayer surfactants were determined from the 2D virial equation of state applied to the isotherms. Film structure signatures were derived from – A isotherm hysteresis and application of the 2D polymer scaling theory. The stress-relaxation measurements revealed a two-step relaxation process at the interface with characteristic times 1 (1.1–2.8 and 2 (5.6-25.6 seconds suggesting the presence of diffusion-controlled and structural organization relaxation phenomena. The results demonstrate that natural films are a complex mixture of biomolecules covering a wide range of solubilities, surface activity and molecular mass with an apparent structural organization exhibiting a spatial and temporal variability.

  20. Thermal instability of DLC film surface morphology - an AFM study

    Science.gov (United States)

    Maheswaran, R.; Thiruvadigal, D. John; Gopalakrishnan, C.

    2012-06-01

    The surface morphology of the DLC film during thermal annealing at particular temperature above the graphitization temperature shows blistering and buckling and also delaminates from the substrate. The DLC film shows poor thermal stability at higher temperature.

  1. Edible arabinoxylan-based films. 1. Effects of lipid type on water vapor permeability, film structure, and other physical characteristics.

    Science.gov (United States)

    Péroval, Claudine; Debeaufort, Frédéric; Despré, Denis; Voilley, Andrée

    2002-07-01

    Arabinoxylans (AX) are natural fibers extracted from maize bran, an industrial byproduct. To promote this polymer as a food ingredient, development of edible coatings and films had been proposed. Indeed, composite arabinoxylan-based films were prepared by emulsifying a fat: palmitic acid, oleic acid, triolein, or a hydrogenated palm oil (OK35). Lipid effects on water vapor permeability (WVP), surface hydrophobicity (contact angles), lipid particle size, and mechanical properties were investigated. Results showed that OK35-AX emulsion films had the lowest WVP. Emulsified films presented a bimodal particle size distribution; however, the smallest particle mean diameter (0.54 microm) was observed in OK35-AX emulsion films. Contact angles of water comparable to those observed for LDPE films (>90 degrees ) are measured on the OK35-AX film surface. Finally, only triolein-AX emulsion films had elongation higher than films without lipid. These results suggest that OK35 enhances functional properties of AX-based films and should be retained for further research.

  2. Surface studies of magnetic thin films

    CERN Document Server

    Zeybek, O

    2000-01-01

    Despite the resonances of the various multiplet components the dichroism signal retains a uniform spectral shape. The well-resolved multiplet structures have been obtained in 5p photoemission of Tb using circularly polarised light. This multiplet structure is caused by the interaction between the core level photohole and those partially filled subshell, i.e. as result of the unpaired 4f and 5p electrons. In 4f levels of Tb(0001) films, the well-resolved surface component of the Tb sup 8 S sub 7 sub / sub 2 has been observed a separation of magnetic circular dichroism in the angular dependence effect for the surface layer and for the bulk. Depending on the preparation procedure, new iron superstructures on W(110) substrate have been observed. The photographs of the LEED images provide information about the ordered arrangement of atoms on the surface and the distances between the spots. These LEED patterns are also an evidence of crystal structure of iron films. The sharpness of the spots gives insight on how w...

  3. CZTSSe thin film solar cells: Surface treatments

    Science.gov (United States)

    Joglekar, Chinmay Sunil

    Chalcopyrite semiconducting materials, specifically CZTS, are a promising alternative to traditional silicon solar cell technology. Because of the high absorption coefficient; films of the order of 1 micrometer thickness are sufficient for the fabrication of solar cells. Liquid based synthesis methods are advantageous because they are easily scalable using the roll to roll manufacturing techniques. Various treatments are explored in this study to enhance the performance of the selenized CZTS film based solar cells. Thiourea can be used as a sulfur source and can be used to tune band gap of CZTSSe. Bromine etching can be used to manipulate the thickness of sintered CZTSSe film. The etching treatment creates recombination centers which lead to poor device performance. Various after treatments were used to improve the performance of the devices. It was observed that the performance of the solar cell devices could not be improved by any of the after treatment steps. Other surface treatment processes are explored including KCN etching and gaseous H2S treatments. Hybrid solar cells which included use of CIGS nanoparticles at the interface between CZTSSe and CdS are also explored.

  4. Surface morphology of ultrathin graphene oxide films obtained by the SAW atomization

    Science.gov (United States)

    Balachova, Olga V.; Balashov, Sergey M.; Costa, Carlos A. R.; Pavani Filho, A.

    2015-08-01

    Lately, graphene oxide (GO) thin films have attracted much attention: they can be used as humidity-sensitive coatings in the surface acoustic wave (SAW) sensors; being functionalized, they can be used in optoelectronic or biodevices, etc. In this research we study surface morphology of small-area thin GO films obtained on Si and quartz substrates by deposition of very small amounts of H2O-GO aerosols produced by the SAW atomizer. An important feature of this method is the ability to work with submicrovolumes of liquids during deposition that provides relatively good control over the film thickness and quality, in particular, minimization of the coffee ring effect. The obtained films were examined using AFM and electron microscopy. Image analysis showed that the films consist of GO sheets of different geometry and sizes and may form discrete or continuous coatings at the surface of the substrates with the minimum thickness of 1.0-1.8 nm which corresponds to one or two monolayers of GO. The thickness and quality of the deposited films depend on the parameters of the SAW atomization (number of atomized droplets, a volume of the initial droplet, etc.) and on sample surface preparation (activation in oxygen plasma). We discuss the structure of the obtained films, uniformity and the surface coverage as a function of parameters of the film deposition process and sample preparation. Qualitative analysis of adhesion of GO films is made by rinsing the samples in DI water and subsequent evaluation of morphology of the remained films.

  5. Total Phosphorus in Surface Water

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess phosphorus in surface water can result in eutrophication. TOTALP is reported in kilograms/hectare/year. More information about these resources, including the...

  6. Total Nitrogen in Surface Water

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALN is reported in kilograms/hectare/year. More information about these resources, including the...

  7. Free Surface Water Tunnel (FSWT)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Free Surface Water Tunnel consists of the intake plenum, the test section and the exit plenum. The intake plenum starts with a perforated pipe that...

  8. Surface modification of silicon-containing fluorocarbon films prepared by plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Jin, Yoonyoung; Desta, Yohannes; Goettert, Jost; Lee, G. S.; Ajmera, P. K.

    2005-07-01

    Surface modification of silicon-containing fluorocarbon (SiCF) films achieved by wet chemical treatments and through x-ray irradiation is examined. The SiCF films were prepared by plasma-enhanced chemical vapor deposition, using gas precursors of tetrafluoromethane and disilane. As-deposited SiCF film composition was analyzed by x-ray photoelectron spectroscopy. Surface modification of SiCF films utilizing n-lithiodiaminoethane wet chemical treatment is discussed. Sessile water-drop contact angle changed from 95°+/-2° before treatment to 32°+/-2° after treatment, indicating a change in the film surface characteristics from hydrophobic to hydrophilic. For x-ray irradiation on the SiCF film with a dose of 27.4 kJ/cm3, the contact angle of the sessile water drop changed from 95°+/-2° before radiation to 39°+/-3° after x-ray exposure. The effect of x-ray exposure on chemical bond structure of SiCF films is studied using Fourier transform infrared measurements. Electroless Cu deposition was performed to test the applicability of the surface modified films. The x-ray irradiation method offers a unique advantage in making possible surface modification in a localized area of high-aspect-ratio microstructures. Fabrication of a Ti-membrane x-ray mask is introduced here for selective surface modification using x-ray irradiation.

  9. A Vertical Draining Film with an Insoluble Surfactant and Nonlinear Surface Properties

    Science.gov (United States)

    Naire, Shailesh; Braun, Richard; Snow, Steve

    2000-11-01

    The drainage of a thin Newtonian film with an insoluble surfactant is studied theoretically in 1+1 dimensions. Lubrication theory is applied to the thin film, which is suspended vertically from a frame and drains into a bath. Three nonlinear partial differential equations (PDEs) govern the evolution of the film shape, surface velocity and surfactant concentration. The surface viscosity and the surface tension of the films are nonlinear functions of the surface concentration; the functions are of the form defined by Lopez and Hirsa for hemicyanine in water. At high concentrations the effects from surface viscosity and the Marangoni effect become more pronounced. Slow and fast draining limits can still be reached and a Marangoni-driven wave that is very localized may be observed. In some instances, the film surface may even be swept clean over some part of its length. When the surface is swept clean, we expect that a vertical film cannot be made for any useful length of time. This is in agreement with expected behavior when films are made with insoluble surfactants; the surface concentration must be high in order for the film to last. This work has been partially supported by the NSF and Dow Corning.

  10. Influence of additive element on surface oxide film of A356 alloy

    Institute of Scientific and Technical Information of China (English)

    OUYANG Zhi-ying; LIANG Hong-yu; MAO Xie-min; HONG Mei

    2006-01-01

    The influences of RE-modification and Sr-modification on the hydrogen content and surface oxide film of A356 aluminum alloy melt were investigated. The hydrogen content of the melt was measured by reduce pressure test. The phases in the surface oxide film were analyzed by X-ray diffractometry (XRD), and the morphology of the surface oxide film was observed by scanning electronic microscopy (SEM). The results show that RE-modification reduces the hydrogen content of A356 aluminum alloy greatly.Contrarily, Sr-modification increases the hydrogen content remarkably. After being treated with RE, a large number of LaAl11O18 consisting of Al2O3 and La2O3, are generated in the surface oxide film of A356 alloy. The surface oxide film of Sr-modification is almost composed of Al2SrO4. According to the results of SEM, the surface oxide film of Sr-modification is very easy to crack,destroy the continuity and compactness of surface oxide film, accelerate the vapor diffusing into the melt, consequently, increase the hydrogen content of A356 alloy melt significantly. But RE-modification makes the surface oxide film compact, and restrains the aluminum exposed to water, so reduces the hydrogen content of A356 alloy melt.

  11. Infrared spectroscopy of thin organic films on metal surfaces

    Science.gov (United States)

    Boerio, F. J.; Boerio, J. P.; Bozian, R. C.

    1988-01-01

    The principles of external reflection infrared spectroscopy for obtaining spectra of thin films on surfaces by reflecting infrared radiation from the surface at large, almost grazing angles, were reviewed and new applications were described. Infrared spectra of monomolecular films formed by myristic acid adsorbed from dilute solutions in nitrobenzene onto aluminum and chromium were obtained. Adsorption onto both substrates involved dissociation of the acid groups to form carboxylate species but undissociated monomer was retained in the films formed on aluminum. Myristic acid was adsorbed onto aluminum with a vertical conformation in which the twofold symmetry axes of the carboxylate groups were nearly perpendicular to the surface of the substrate. The twofold axes of the carboxylate groups were more inclined with respect to the normal to the surface for the chromium substrates. Terephthalic acid and terephthalic acid-d 4 were adsorbed onto aluminum from dilute solutions in ethanol with a vertical conformation in which one acid group was dissociated to form a salt with a metal ion in the substrate while the other acid group may have formed hydrogen bonds with neighboring molecules. When thin films of ethylene/vinyl acetate copolymers were applied to the aluminized back sides of silicon solar cells which were then immersed in boiling water for a few minutes, the hydrated oxide pseudoboehmite rapidly formed at the interface. A primer containing γ-methacryoxypropyltrimethoxysilane (γ-MPS) inhibited the formation of pseudoboehmite from the rough aluminized back sides of crystalline silicon cells but not from the smooth aluminized back sides of amorphous cells.

  12. Surface and tribological behaviors of the bioinspired polydopamine thin films under dry and wet conditions.

    Science.gov (United States)

    Zhang, Wei; Yang, Fut K; Han, Yougun; Gaikwad, Ravi; Leonenko, Zoya; Zhao, Boxin

    2013-02-11

    Dopamine is a "sticky" biomolecule containing the typical functional groups of mussel adhesive proteins. It can self-polymerize into a nanoscale thin film on various surfaces. We investigated the surface, adhesion, friction, and cracking properties of polydopamine (PDA) thin films for their effective transfer to functional devices and biocompatible coatings. A series of surface characterizations and mechanical tests were performed to reveal the static and dynamic properties of PDA films coated on glass, polydimethylsiloxane (PDMS), and epoxy. We found that PDA films are highly hydrated under wet conditions because of their porous membrane-like nanostructures and hydrophilic functional groups. Upon dehydration, the films form cracks when they are coated on soft substrates due to internal stresses and the large mismatch in elastic modulus. The adhesive pull-off force or the effective work of adhesion increased with the contact time, suggesting dynamic interactions at the interface. A significant decrease in friction forces in water was observed on all three material surfaces coated with PDA; thus, the film might serve as a water-based lubrication coating. We attributed the different behavior of PDA films in air and in water to its hydration effects. These research findings provide insight into the stability, mechanical, and adhesive properties of the PDA films, which are critical for their applications.

  13. Drainage, rupture, and lifetime of deionized water films: effect of dissolved gases?

    Science.gov (United States)

    Nguyen, Phong T; Nguyen, Anh V

    2010-03-02

    Gas bubbles coalesce in deionized (DI) water because the water (foam) films between the bubbles are not stable. The so-called hydrophobic attraction has been suggested as the cause of the film instability and the bubble coalescence. In this work, microinterferometry experiments show that foam films of ultrapure DI water can last up to 10 s and the contact time between the two gas bubble surfaces at close proximity (approximately 1 microm separation distance) significantly influences the film drainage, rupture, and lifetime. Specifically, when the two bubbles were first brought into contact, the films instantly ruptured at 0.5 microm thickness. However, the film drainage rate and rupture thickness sharply decreased and the film lifetime steeply increased with increasing contact time up to 10 min, but then they leveled off. The constant thickness of film rupture was around 35 nm. Possible contamination was vigorously investigated and ruled out. It is argued that migration of gases inherently dissolved in water might cause the transient behavior of the water films at the short contact time. The film drainage rate and instability at the long contact time were analyzed employing Eriksson et al.'s phenomenological theory of long-range hydrophobic attraction (Eriksson, J. C.; Ljunggren, S.; Claesson, P. M., J. Chem. Soc., Faraday Trans. 2 1989, 85, 163-176) and the hypothesis of water molecular structure modified by dissolved gases, and the extended Stefan-Reynolds theory by incorporating the mobility of the air-DI-water interfaces.

  14. Imprint Control of BaTiO3 Thin Films via Chemically Induced Surface Polarization Pinning.

    Science.gov (United States)

    Lee, Hyungwoo; Kim, Tae Heon; Patzner, Jacob J; Lu, Haidong; Lee, Jung-Woo; Zhou, Hua; Chang, Wansoo; Mahanthappa, Mahesh K; Tsymbal, Evgeny Y; Gruverman, Alexei; Eom, Chang-Beom

    2016-04-13

    Surface-adsorbed polar molecules can significantly alter the ferroelectric properties of oxide thin films. Thus, fundamental understanding and controlling the effect of surface adsorbates are crucial for the implementation of ferroelectric thin film devices, such as ferroelectric tunnel junctions. Herein, we report an imprint control of BaTiO3 (BTO) thin films by chemically induced surface polarization pinning in the top few atomic layers of the water-exposed BTO films. Our studies based on synchrotron X-ray scattering and coherent Bragg rod analysis demonstrate that the chemically induced surface polarization is not switchable but reduces the polarization imprint and improves the bistability of ferroelectric phase in BTO tunnel junctions. We conclude that the chemical treatment of ferroelectric thin films with polar molecules may serve as a simple yet powerful strategy to enhance functional properties of ferroelectric tunnel junctions for their practical applications.

  15. Surface modification of polytetrafluoroethylene film using single liquid electrode atmosphericpressure glow discharge

    Institute of Scientific and Technical Information of China (English)

    Zhou Lan; Lü Guo-Hua; Chen Wei; Pang Hua; Zhang Gu-Ling; Yang Si-Ze

    2011-01-01

    Polytetrafluoroethylene films are treated by room temperature helium atmospheric pressure plasma plumes, which are generated with a home-made single liquid electrode plasma device. After plasma treatment, the water contact angle of polytetrafluoroethylene film drops from 114° to 46° and the surface free energy increases from 22.0 mJ/m2 to 59.1 mJ/m2. The optical emission spectrum indicates that there are reactive species such as O2+, O and He in the plasma plume. After plasma treatment, a highly crosslinking structure is formed on the film surface and the oxygen element is incorporated into the film surface in the forms of -C-O-C-, -C=O, and -O-C=O groups. Over a period of 10 days, the contact angle of the treated film is recovered by only about 10°, which indicates that the plasma surface modification is stable with time.

  16. Surface molecular aggregation structure and surface physicochemical properties of poly(fluoroalkyl acrylate) thin films

    Science.gov (United States)

    Honda, K.; Yamaguchi, H.; Kobayashi, M.; Morita, M.; Takahara, A.

    2008-03-01

    Effect of side chain length on the molecular aggregation states and surface properties of poly(fluoroalkyl acrylate)s [PFA-Cy, where y is fluoromethylene number in Rf group] thin films were systematically investigated. Spin-coated PFA-Cy thin films were characterized by static and dynamic contact angle measurements, X-ray photoelectron spectroscopy (XPS), and grazing- incidence X-ray diffraction (GIXD). The receding contact angles showed small values for PFA-Cy with short side chain (y=8. GIXD revealed that fluoroalkyl side chain of PFA-Cy with y>=8 was crystallized and formed ordered structures at the surface region as well as bulk one. These results suggest that water repellent mechanism of PFA-Cy can be attributed to the presence of highly ordered fluoroalkyl side chains at the outermost surfaces. The results of XPS in the dry and hydrated states and contact angle measurement in water support the mechanism of lowering contact angle for water by exposure of carbonyl group to the water interface through reorientation of short fluoroalkyl chains. The surface nanotextured PFA-C8 through imprinting of anodic aluminum oxide mold showed extremely high hydrophobicity as well as high oleophobicity.

  17. Surface molecular aggregation structure and surface physicochemical properties of poly(fluoroalkyl acrylate) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Honda, K; Yamaguchi, H; Takahara, A [Graduate School of Engineering, Kyushu University, Motooka, Nishi-ku, Fukuoka, 819-0395 (Japan); Kobayashi, M [Institute for Materials Chemistry and Engineering, Kyushu University, Motooka, Nishi-ku, Fukuoka, 819-0395 (Japan); Morita, M [Fundamental Research Department, Chemical Division, Daikin Industries, Ltd., 1-1 Nishi Hitotsuya, Settsu-shi, Osaka 566-8585 (Japan)], E-mail: takahara@cstf.kyushu-u.ac.jp

    2008-03-15

    Effect of side chain length on the molecular aggregation states and surface properties of poly(fluoroalkyl acrylate)s [PFA-C{sub y}, where y is fluoromethylene number in R{sub f} group] thin films were systematically investigated. Spin-coated PFA-C{sub y} thin films were characterized by static and dynamic contact angle measurements, X-ray photoelectron spectroscopy (XPS), and grazing- incidence X-ray diffraction (GIXD). The receding contact angles showed small values for PFA-C{sub y} with short side chain (y{<=}6) and increased above y{>=}8. GIXD revealed that fluoroalkyl side chain of PFA-C{sub y} with y{>=}8 was crystallized and formed ordered structures at the surface region as well as bulk one. These results suggest that water repellent mechanism of PFA-C{sub y} can be attributed to the presence of highly ordered fluoroalkyl side chains at the outermost surfaces. The results of XPS in the dry and hydrated states and contact angle measurement in water support the mechanism of lowering contact angle for water by exposure of carbonyl group to the water interface through reorientation of short fluoroalkyl chains. The surface nanotextured PFA-C{sub 8} through imprinting of anodic aluminum oxide mold showed extremely high hydrophobicity as well as high oleophobicity.

  18. Facile Fabrication of Gradient Surface Based on (meth)acrylate Copolymer Films

    Science.gov (United States)

    Zhang, Y.; Yang, H.; Wen, X.-F.; Cheng, J.; Xiong, J.

    2016-08-01

    This paper describes a simple and economic approach for fabrication of surface wettability gradient on poly(butyl acrylate - methyl methacrylate) [P (BA-MMA)] and poly(butyl acrylate - methyl methacrylate - 2-hydroxyethyl methacrylate) [P (BA-MMA-HEMA)] films. The (meth)acrylate copolymer [including P (BA-MMA) and P (BA-MMA-HEMA)] films are hydrolyzed in an aqueous solution of NaOH and the transformation of surface chemical composition is achieved by hydrolysis in NaOH solution. The gradient wetting properties are generated based on different functional groups on the P (BA-MMA) and P (BA-MMA-HEMA) films. The effects of both the surface chemical and surface topography on wetting of the (meth)acrylate copolymer film are discussed. Surface chemical composition along the materials length is determined by XPS, and surface topography properties of the obtained gradient surfaces are analyzed by FESEM and AFM. Water contact angle system (WCAs) results show that the P (BA-MMA-HEMA) films provide a larger slope of the gradient wetting than P (BA-MMA). Moreover, this work demonstrates that the gradient concentration of chemical composition on the poly(meth) acrylate films is owing to the hydrolysis processes of ester group, and the hydrolysis reactions that have negligible influence on the surface morphology of the poly(meth) acrylate films coated on the glass slide. The gradient wettability surfaces may find broad applications in the field of polymer coating due to the compatibility of (meth) acrylate polymer.

  19. Dielectric Characterization of Confined Water in Chiral Cellulose Nanocrystal Films.

    Science.gov (United States)

    Natarajan, Bharath; Emiroglu, Caglar; Obrzut, Jan; Fox, Douglas M; Pazmino, Beatriz; Douglas, Jack F; Gilman, Jeffrey W

    2017-04-26

    A known deterrent to the large-scale development and use of cellulose nanocrystals (CNCs) in composite materials is their affinity for moisture, which has a profound effect on dispersion, wetting, interfacial adhesion, matrix crystallization, water uptake, and hydrothermal stability. To quantify and control the hydration and confinement of absorbed water in CNCs, we studied sulfated-CNCs neutralized with sodium cations and CNCs functionalized with less hydrophilic methyl(triphenyl)phosphonium cations. Films were cast from water suspensions at 20 °C under controlled humidity and drying rate, yielding CNC materials with distinguishably different dielectric properties and cholesteric structures. By controlling the evaporation rate, we obtained self-assembled chiral CNC films with extended uniformity, having helical modulation length (nominal pitch) tunable from 1300 to 600 nm. SEM imaging and UV-vis-NIR total reflectance spectra revealed tighter and more uniform CNC packing in films cast at slow evaporation rates or having lower surface energy when modified with phosphonium. The dielectric constant was measured by a noncontact microwave cavity perturbation method and fitted to a classical mixing model employing randomly oriented ellipsoidal water inclusions. The dielectric constant of absorbed water was found to be significantly smaller than that for free liquid indicating a limited mobility due to binding with the CNC "matrix". In the case of hydrophilic Na-modified CNCs, a decreasing pitch led to greater anisotropy in the shape of moisture inclusions (ellipsoidal to platelet-like) and greater confinement. In contrast, the structure of hydrophobic phosphonium-modified CNC films was found to have reduced pitch, yet the shape of confined water remained predominantly spherical. These results provide a useful perspective on the current state of understanding of CNC-water interactions as well as on CNC self-assembly mechanisms. More broadly, we believe that our results

  20. Influence of organic films on the evaporation and condensation of water in aerosol.

    Science.gov (United States)

    Davies, James F; Miles, Rachael E H; Haddrell, Allen E; Reid, Jonathan P

    2013-05-28

    Uncertainties in quantifying the kinetics of evaporation and condensation of water from atmospheric aerosol are a significant contributor to the uncertainty in predicting cloud droplet number and the indirect effect of aerosols on climate. The influence of aerosol particle surface composition, particularly the impact of surface active organic films, on the condensation and evaporation coefficients remains ambiguous. Here, we report measurements of the influence of organic films on the evaporation and condensation of water from aerosol particles. Significant reductions in the evaporation coefficient are shown to result when condensed films are formed by monolayers of long-chain alcohols [C(n)H(2n+1)OH], with the value decreasing from 2.4 × 10(-3) to 1.7 × 10(-5) as n increases from 12 to 17. Temperature-dependent measurements confirm that a condensed film of long-range order must be formed to suppress the evaporation coefficient below 0.05. The condensation of water on a droplet coated in a condensed film is shown to be fast, with strong coherence of the long-chain alcohol molecules leading to islanding as the water droplet grows, opening up broad areas of uncoated surface on which water can condense rapidly. We conclude that multicomponent composition of organic films on the surface of atmospheric aerosol particles is likely to preclude the formation of condensed films and that the kinetics of water condensation during the activation of aerosol to form cloud droplets is likely to remain rapid.

  1. Modeling surface imperfections in thin films and nanostructured surfaces

    Science.gov (United States)

    Hansen, P.-E.; Madsen, J. S.; Jensen, S. A.; Madsen, M. H.; Karamehmedovic, M.

    2017-06-01

    Accurate scatterometry and ellipsometry characterization of non-perfect thin films and nanostructured surfaces are challenging. Imperfections like surface roughness make the associated modelling and inverse problem solution difficult due to the lack of knowledge about the imperfection on the surface. Combining measurement data from several instruments increases the knowledge of non-perfect surfaces. In this paper we investigate how to incorporate this knowledge of surface imperfection into inverse methods used in scatterometry and ellipsometry using the Rigorous Coupled Wave Analysis. Three classes of imperfections are examined. The imperfections are introduced as periodic structures with a super cell periods ten times larger than the simple grating period. Two classes of imperfections concern the grating and one class concern the substrate. It is shown that imperfections of a few nanometers can severely change the reflective response on silicon gratings. Inverse scatterometry analyses of gratings with imperfection using simulated data with white noise have been performed. The results show that scatterometry is a robust technology that is able to characterize grating imperfections provided that the imperfection class is known.

  2. Equilibrium Water Contents of Cellulose Films Determined via Solvent Exchange and Quartz Crystal Microbalance with Dissipation Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kittle, Joshua D; Du, Xiaosong; Jiang, Feng; Qian, Chen; Heinze, Thomas; Roman, Maren; Esker, Alan R

    2011-08-08

    Model cellulose surfaces have attracted increasing attention for studying interactions with cell wall matrix polymers and as substrates for enzymatic degradation studies. Quartz crystal microbalance with dissipation monitoring (QCM-D) solvent exchange studies showed that the water content of regenerated cellulose (RC) films was proportional to the film thickness (d) and was consistent with about five water molecules per anhydroglucose unit. Sulfated nanocrystalline cellulose (SNC) and desulfated nanocrystalline cellulose (DNC) films had comparable water contents and contained about five times more water than RC films. A cellulase mixture served as a probe for studies of substrate accessibility and degradation. Cellulase adsorption onto RC films was independent of d, whereas degradation times increased with d. However, adsorption onto SNC and DNC films increased with d, whereas cellulase degradation times for DNC films were independent of studied d. Enhanced access to guest molecules for SNC and DNC films revealed they are more porous than RC films.

  3. Equilibrium water contents of cellulose films determined via solvent exchange and quartz crystal microbalance with dissipation monitoring.

    Science.gov (United States)

    Kittle, Joshua D; Du, Xiaosong; Jiang, Feng; Qian, Chen; Heinze, Thomas; Roman, Maren; Esker, Alan R

    2011-08-08

    Model cellulose surfaces have attracted increasing attention for studying interactions with cell wall matrix polymers and as substrates for enzymatic degradation studies. Quartz crystal microbalance with dissipation monitoring (QCM-D) solvent exchange studies showed that the water content of regenerated cellulose (RC) films was proportional to the film thickness (d) and was consistent with about five water molecules per anhydroglucose unit. Sulfated nanocrystalline cellulose (SNC) and desulfated nanocrystalline cellulose (DNC) films had comparable water contents and contained about five times more water than RC films. A cellulase mixture served as a probe for studies of substrate accessibility and degradation. Cellulase adsorption onto RC films was independent of d, whereas degradation times increased with d. However, adsorption onto SNC and DNC films increased with d, whereas cellulase degradation times for DNC films were independent of studied d. Enhanced access to guest molecules for SNC and DNC films revealed they are more porous than RC films.

  4. Soap opera : polymer-surfactant interactions on thin film surfaces /

    Energy Technology Data Exchange (ETDEWEB)

    Ozer, B. H. (Byram H.); Johal, M. S. (Malkiat S.); Wang, H. L. (Hsing-Lin); Robinson, J. M. (Jeanne M.)

    2001-01-01

    Surfactants are macromolecules with unique properties. They commonly contain a polar head group with a nonpolar hydrocarbon chain. These properties allow surfactants to solubilize greases and other nonpolar molecules. One particular way that this is accomplished is through the formation of micelles. Micelles are formed at the critical micelle concentration (cmc), which varies depending upon the nature of the surfactant and also the media in which the surfactant resides. These micelles can take a variety of shapes, but are generally characterized by surrounding the grease with the nonpolar hydrocarbon chains, exposing only the polarized head groups to the media, usually water. This property of easy solubilization has made surfactants a very attractive industrial agent, They are used most conventionally as industrial cleaning agents and detergents. However, they also have lesser-known applications in conjunction with polymers and other macromolecular mixtures, often creating a system with novel properties, such as increased solubilization and smoother mixture consistency. A recently developed field has investigated the self-assembly of polymers and polyelectrolytes onto thin film surfaces. There are many reasons for studying this process, such as for second harmonic generation purposes and bioassays. In this study, the interaction between the anionic polyelectrolyte poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and two surfactants of opposite charge, Sodium Dodecyl Sulfate (SDS) and Dodecyl Trimethyl Ammonium Bromide (DTAB), in their assembly onto thin film surfaces was investigated. The kinetics of adsorbance onto the thin films was examined, followed by construction of 10-bilayer films using an alternating layer of the cationic polyelectrolyte poly(ethylenimine) (PEI) to provide the electrostatic means for the PAZO/surfactant combination to assemble onto the thin film. The kinetics of adsorption is being

  5. Enhanced convective and film boiling heat transfer by surface gas injection

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M.R.; Greene, G.A. (Brookhaven National Lab., Upton, NY (United States)); Irvine, T.F., Jr. (State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering)

    1992-04-01

    Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured (0 to 8.5 cm/s), the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.

  6. Enhanced convective and film boiling heat transfer by surface gas injection

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M.R.; Greene, G.A. [Brookhaven National Lab., Upton, NY (United States); Irvine, T.F., Jr. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering

    1992-04-01

    Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus_minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured [0 to 8.5 cm/s], the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.

  7. Analysis of method of polarization surveying of water surface oil pollution

    Science.gov (United States)

    Zhukov, B. S.

    1979-01-01

    A method of polarization surveying of oil films on the water surface is analyzed. Model calculations of contrasted oil and water obtained with different orientations of the analyzer are discussed. The model depends on the spectral range, water transparency and oil film, and the selection of observational direction.

  8. Groundwater–Surface Water Exchange

    DEFF Research Database (Denmark)

    Karan, Sachin

    The exchange of groundwater-surface water has been invetigated in the western part of Denmark. Holtum AA provides the framework for all the performed investigations. Several methods are used, primarily eld based measurements ombined with numerical models to achieve insight to the governing...... processes of interaction between groundwater and surface water. By using heat as a tracer it has been possible to use temperature directly as calibrationtargets in a groundwater and heat transport model. Thus, it is possible to use heat investigate the change in groundwater discharge in dynamic conditions...... by using simple temperature devices along a stream to delineate the areas of interest in regard to GW{SW exchange. Thus, at several locations in a stream a temperature data logger was placed in the water column and right at the streambed-water interface. By looking at the correlation of streambed...

  9. Groundwater–Surface Water Exchange

    DEFF Research Database (Denmark)

    Karan, Sachin

    The exchange of groundwater-surface water has been invetigated in the western part of Denmark. Holtum AA provides the framework for all the performed investigations. Several methods are used, primarily eld based measurements ombined with numerical models to achieve insight to the governing...... processes of interaction between groundwater and surface water. By using heat as a tracer it has been possible to use temperature directly as calibrationtargets in a groundwater and heat transport model. Thus, it is possible to use heat investigate the change in groundwater discharge in dynamic conditions...... by using simple temperature devices along a stream to delineate the areas of interest in regard to GW{SW exchange. Thus, at several locations in a stream a temperature data logger was placed in the water column and right at the streambed-water interface. By looking at the correlation of streambed...

  10. Monitoring tablet surface roughness during the film coating process

    DEFF Research Database (Denmark)

    Seitavuopio, Paulus; Heinämäki, Jyrki; Rantanen, Jukka

    2006-01-01

    the process of film coating tablets were studied by noncontact laser profilometry and scanning electron microscopy (SEM). An EDX analysis was used to monitor the magnesium stearate and titanium dioxide of the tablets. The tablet cores were film coated with aqueous hydroxypropyl methylcellulose, and the film...... coating was performed using an instrumented pilot-scale side-vented drum coater. The SEM images of the film-coated tablets showed that within the first 30 minutes, the surface of the tablet cores was completely covered with a thin film. The magnesium signal that was monitored by SEM-EDX disappeared after...... ~15 to 30 minutes, indicating that the tablet surface was homogeneously covered with film coating. The surface roughness started to increase from the beginning of the coating process, and the increase in the roughness broke off after 30 minutes of spraying. The results clearly showed that the surface...

  11. Bioinspired molecular adhesive for water-resistant oxygen indicator films.

    Science.gov (United States)

    Vu, Chau Hai Thai; Won, Keehoon

    2013-01-01

    Mussels can attach themselves to nearly all types of hard surfaces in wet environments. Such attractive adhesive ability of mussels is believed to rely on the amino acid composition of proteins found near the plaque-substrate interface. Dopamine (DA) is identified as a simplified mimic of mussel proteins, which are rich in 3,4-dihydroxy-L-phenylalanine and lysine, because it contains both catechol and amine functional groups. In this work, we have first applied this bioinspired adhesive to tackle a dye leaching problem of colorimetric oxygen indicator films, which are widely used to ensure the absence of oxygen inside the package of oxygen-sensitive materials. Simple immersion of packaging films into a DA solution resulted in poly(DA) deposition, decreasing the water contact angle of the films from 105° to 65°. The poly(DA) coating could reduce the thionine leakage of the UV-activated oxygen indicator film. The effects of poly(DA) coating were found to be dependent on the DA solution pH, the coating time, and the DA concentration. The film resistant to dye leaching lost its dye color by 5 min UVB irradiation and regained the color in the presence of oxygen, demonstrating that it functioned successfully as UV-activated oxygen indicators.

  12. Simple and cost-effective fabrication of highly flexible, transparent superhydrophobic films with hierarchical surface design.

    Science.gov (United States)

    Kim, Tae-Hyun; Ha, Sung-Hun; Jang, Nam-Su; Kim, Jeonghyo; Kim, Ji Hoon; Park, Jong-Kweon; Lee, Deug-Woo; Lee, Jaebeom; Kim, Soo-Hyung; Kim, Jong-Man

    2015-03-11

    Optical transparency and mechanical flexibility are both of great importance for significantly expanding the applicability of superhydrophobic surfaces. Such features make it possible for functional surfaces to be applied to various glass-based products with different curvatures. In this work, we report on the simple and potentially cost-effective fabrication of highly flexible and transparent superhydrophobic films based on hierarchical surface design. The hierarchical surface morphology was easily fabricated by the simple transfer of a porous alumina membrane to the top surface of UV-imprinted polymeric micropillar arrays and subsequent chemical treatments. Through optimization of the hierarchical surface design, the resultant superhydrophobic films showed superior surface wetting properties (with a static contact angle of >170° and contact angle hysteresis of 82% at 550 nm wavelength). The superhydrophobic films were also experimentally found to be robust without significant degradation in the superhydrophobicity, even under repetitive bending and pressing for up to 2000 cycles. Finally, the practical usability of the proposed superhydorphobic films was clearly demonstrated by examining the antiwetting performance in real time while pouring water on the film and submerging the film in water.

  13. Surface Stability of Epitaxial Elastic Films by the Casimir Force

    Science.gov (United States)

    Zhao, Ya-Pu; Li, Wen J.

    2002-08-01

    We investigate the morphological stability of epitaxial thin elastic films on a substrate by the Casimir force between the film surface and a flat plate. Critical undulation wavelengths are derived for two different limit conditions. Consideration of the Casimir force in both limit cases decreases the critical wavelength of the surface perturbation.

  14. Surface Stability of Epitaxial Elastic Films by the Casimir Force

    Institute of Scientific and Technical Information of China (English)

    赵亚溥; 李文荣

    2002-01-01

    We investigate the morphological stability of epitaxial thin elastic films on a substrate by the Casimir force between the film surface and a flat plate. Critical undulation wavelengths are derived for two different limit conditions. Consideration of the Casimir force in both limit cases decreases the critical vavelength of the surface perturbation.

  15. Model Research on the Effect of Surface Film on Ammonia Volatilization from Rice Field

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Shun-yao; YIN Bin; ZHU Zhao-liang

    2002-01-01

    Pan and field experiments were conducted to investigate the effect of surface film on ammonia volatilization from water and paddy soil. The results showed that the addition of the surface film on floodwater reduced the rate of ammonia volatilization, however, the reduction of the latter varied greatly with its rates of addition. Jayaweera-Mikkelsen ammonia volatilization model with the introduction of a parameter Kf, a relative measure of the resistance of the surface film on ammonia volatilization, was used to elucidate the effectiveness of the surface film on lowering ammonia volatilization. The Kf value was calculated from the results obtained in the pan experiment with different rates of surface film addition. With the modified model and the optimized Kf value, the effects of the surface film in reducing ammonia volatilization under different environmental conditions were simulated and analyzed. However, it was found that the simulation was not satisfactory in the field experiment and the parameter Kf should be further tuned so as to improve the simulation and to optimize the addition rate of the surface film in field conditions.

  16. RUPTURING OF POLYMER FILMS WITH RUBBING-INDUCED SURFACE DEFECTS

    Institute of Scientific and Technical Information of China (English)

    B.Du; F.C.Xie; Y.J.Wang; O.K.C.Tsui

    2003-01-01

    It has been a long-standing question whether dewetting of polymer film from non-wettable substrate surfaces wherein the bicontinuous morphology never forms in the dewetting film is due to spinodal instability or heterogeneous nucleation. In this experiment, we use a simple method to make the distinction through introduction of topographical defects of the films by rubbing the sample surface with a rayon cloth. Spinodal dewetting is identified for those films that dewet by a characteristic wavevector, q*, independent of the density of rubbing-induced defects. Heterogeneous nucleation, on the other hand, is identified for those with q* increasing with increasing density of defects. Our result shows that PS films on oxide coated silicon with thickness less than ≈ 13 nm are dominated by spinodal dewetting, but the thicker films are dominated by nucleation dewetting. We also confirm that spinodal dewetting does not necessarily lead to a bicontinuous morphology in the dewetting film, contrary to the classic theory of Cahn.

  17. How to repel hot water from a superhydrophobic surface?

    KAUST Repository

    Yu, Zhejun

    2014-01-01

    Superhydrophobic surfaces, with water contact angles greater than 150° and slide angles less than 10°, have attracted a great deal of attention due to their self-cleaning ability and excellent water-repellency. It is commonly accepted that a superhydrophobic surface loses its superhydrophobicity in contact with water hotter than 50 °C. Such a phenomenon was recently demonstrated by Liu et al. [J. Mater. Chem., 2009, 19, 5602], using both natural lotus leaf and artificial leaf-like surfaces. However, our work has shown that superhydrophobic surfaces maintained their superhydrophobicity, even in water at 80 °C, provided that the leaf temperature is greater than that of the water droplet. In this paper, we report on the wettability of water droplets on superhydrophobic thin films, as a function of both their temperatures. The results have shown that both the water contact and slide angles on the surfaces will remain unchanged when the temperature of the water droplet is greater than that of the surface. The water contact angle, or the slide angle, will decrease or increase, however, with droplet temperatures increasingly greater than that of the surfaces. We propose that, in such cases, the loss of superhydrophobicity of the surfaces is caused by evaporation of the hot water molecules and their condensation on the cooler surface. © 2014 the Partner Organisations.

  18. Surface Morphology of Annealed Lead Phthalocyanine Thin Films

    Directory of Open Access Journals (Sweden)

    P.Kalugasalam,

    2010-06-01

    Full Text Available The thin films of Lead Phthalocyanine (PbPc on glass substrates were prepared by Vacuum deposition. The thickness of the films was 450 nm. The sample annealed in high vacuum at 373 K temperature. The sample has been analysed by X-ray diffraction, scanning electron microscopy and atomic force microscopy in order to get structural and surface morphology of the PbPc thin film. The formation of XRD patterns of PbPc shows a triclinic grains (T seen along with monoclinic (M forms of PbPc. The sample is annealed at 373 K temperatures; the film shows peaks that assigned to the triclinic phase. SEM and AFM are the best tools to investigate the surface smoothness and to find the grain size of the particles. The grain size is calculated for all films of different thicknesses. The annealed AFM micrograph shows that the surface of the films consists of large holes. The annealed AFM image indicates a smooth surface. It is very clear that the grain size decreases with increase in the annealing temperature. The roughness also decreases with the increase in film annealing temperature. Annealed film leads to the oxidation of the hthalocyanine with oxygen absorbed or diffused. Therefore, the heat is responsible for the increase in film thickness. Since the films expand, it is believed that the porosity is increased.

  19. Spinodal surface instability of soft elastic thin films

    Science.gov (United States)

    Huang, Shi Qing; Feng, Xi Qiao

    2008-06-01

    When the thicknesses of thin films reduce to microns or even nanometers, surface energy and surface interaction often play a significant role in their deformation behavior and surface morphology. The spinodal surface instability induced by the van der Waals force in a soft elastic thin film perfectly bonded to a rigid substrate is investigated theoretically using the bifurcation theory of elastic structures. The analytical solution is derived for the critical condition of spinodal surface morphology instability by accounting for the competition of the van der Waals interaction energy, elastic strain energy and surface energy. Detailed examinations on the effect of surface energy, thickness and elastic properties of the film show that the characteristic wavelength of the deformation bifurcation mode depends on the film thickness via an exponential relation, with the power index in the range from 0.749 to 1.0. The theoretical solution has a good agreement with relevant experiment results.

  20. Spinodal surface instability of soft elastic thin films

    Institute of Scientific and Technical Information of China (English)

    Shi Qing Huang; Xi Qiao Feng

    2008-01-01

    When the thicknesses of thin films reduce to microns or even nanometers, surface energy and surface interaction often play a significant role in their deformation behavior and surface morphology. The spinodal surface instability induced by the van der Waals force in a soft elastic thin film perfectly bonded to a rigid substrate is investigated theoretically using the bifurcation theory of elastic structures. The analytical solution is derived for the critical condition of spinodal surface morphology instability by accounting for the competition of the van der Waals interaction energy, elastic strain energy and surface energy. Detailed examinations on the effect of surface energy, thickness and elastic propeties of the film show that the characteristic wavelength of the deformation bifurcation mode depends on the film thickness via an exponential relation, with the power index in the range from 0.749 to 1.0. The theoretical solution has a good agreement with relevant experiment results.

  1. Development of Water-triggered Chitosan Film Containing Glucamylase for Sustained Release of Resveratrol.

    Science.gov (United States)

    Zhang, Dongliang; Cao, Yanfei; Ma, Chengye; Chen, Shanfeng; Li, Hongjun

    2017-02-15

    There was a paradox to incorporate enzyme into edible chitosan film that chitosan was dissolved in acid solution and enzyme activity was maintained in mild condition. This study presents a suitable method for maintaining the pH of the chitosan solution at 4-6 to prepare a sustained-release film containing β-cyclodextrin, resveratrol-β-cyclodextrin inclusion (RCI), glucamylase and acetic acid. A considerable amount of resveratrol was released by the glucamylase-incorporated film within 15 days, and the maximum amount released was 46% of the total resveratrol content. The highest resveratrol release ratio (released resveratrol/total resveratrol) was obtained in the film with 6 mL of RCI. Scratches and spores were generated on the surface of the glucamylase-added film immersed in water (GAFW) for 7 days because of β-cyclodextrin hydrolysis during film drying and water immersion. RCI and β-cyclodextrin were extruded from the film surface and formed teardrops, which were erased by water on the GAFW surface but appeared on the glucamylase-added film without water immersion (GAF). The bubbles generated by the reaction of acetic acid and residual sodium bicarbonate were observed in both glucamylase-free films immersed in water (GFFW) for 7 days and without water immersion (GFF). The FT-IR spectra illustrated that covalent bond was not generated during water immersion and β-cyclodextrin hydrolysis. The crystal structure of chitosan was destroyed by water immersion and β-cyclodextrin hydrolysis, resulting in the lowest chitosan crystallization peak at 22°. The increasing of water holding capacity determined by EDS presented the following order: GAF, GFFW, GFF and GAFW.

  2. Mobile surface water filtration system

    Directory of Open Access Journals (Sweden)

    Aashish Vatsyayan

    2012-09-01

    Full Text Available To design a mobile system for surface water filtrationMethodology: the filtration of surface impurities begins with their retraction to concentrated thickness using non ionising surfactants, then isolation using surface tension property and sedimentation of impurities in process chamber using electrocoagulation. Result:following studies done to determine the rate of spreading of crude oil on water a method for retraction of spread crude oil to concentrated volumes is developed involving addition of non -ionising surfactants in contrast to use of dispersants. Electrocoagulation process involves multiple processes taking place to lead to depositionof impurities such as oil, grease, metals. Studies of experiments conducted reveals parameters necessary for design of electrocoagulation process chamber though a holistic approach towards system designing is still required. Propeller theory is used in determining the required design of propeller and the desired thrust, the overall structure will finally contribute in deciding the choice of propeller.

  3. Water drop impact onto oil covered solid surfaces

    Science.gov (United States)

    Chen, Ningli; Chen, Huanchen; Amirfazli, Alidad

    2016-11-01

    Droplet impact onto an oily surface can be encountered routinely in industrial applications; e.g., in spray cooling. It is not clear from literature what impact an oil film may have on the impact process. In this work, water drop impact onto both hydrophobic (glass) and hydrophilic (OTS) substrates which were covered by oil films (silicone) of different thickness (5um-50um) and viscosity (5cst-100cst) were performed. The effects of drop impact velocity, film thickness, and viscosity of the oil film and wettability of the substrate were studied. Our results show that when the film viscosity and impact velocity is low, the water drop deformed into the usual disk shape after impact, and rebounded from the surface. Such rebound phenomena disappears, when the viscosity of oil becomes very large. With the increase of the impact velocity, crown and splashing appears in the spreading phase. The crown and splashing behavior appears more easily with the increase of film thickness and decrease of its viscosity. It was also found that the substrate wettability can only affect the impact process in cases which drop has a large Webber number (We = 594), and the film's viscosity and thickness are small. This work was support by National Natural Science Foundation of China and the Project Number is 51506084.

  4. Formation of mixed and patterned self-assembled films of alkylphosphonates on commercially pure titanium surfaces

    Science.gov (United States)

    Rudzka, Katarzyna; Sanchez Treviño, Alda Y.; Rodríguez-Valverde, Miguel A.; Cabrerizo-Vílchez, Miguel A.

    2016-12-01

    Titanium is extensively employed in biomedical devices, in particular as implant. The self-assembly of alkylphosphonates on titanium surfaces enable the specific adsorption of biomolecules to adapt the implant response against external stimuli. In this work, chemically-tailored cpTi surfaces were prepared by self-assembly of alkylphosphonate molecules. By bringing together attributes of two grafting molecules, aqueous mixtures of two alkylphosphonates were used to obtain mixed self-assembled films. Single self-assembled films were also altered by laser abrasion to produce chemically patterned cpTi surfaces. Both mixed and patterned self-assembled films were confirmed by AFM, ESEM and X-ray photoelectron spectroscopy. Water contact angle measurements also revealed the composition of the self-assembly films. Chemical functionalization with two grafting phosphonate molecules and laser surface engineering may be combined to guide the bone-like formation on cpTi, and the future biological response in the host.

  5. Undulatory delamination of thin polymer films on gold surfaces.

    Science.gov (United States)

    Chah, Soonwoo; Noolandi, Jaan; Zare, Richard N

    2005-10-20

    Using two-dimensional surface plasmon resonance measurements, we have observed the formation of traveling waves in the delamination of thin films of polydimethylsilane (PDMS) exposed to methanol. Films were spin-coated on a gold surface and the methanol was added to the top surface. The stress-induced instability caused by the swelling of the PDMS thin film when its edge is pinned to the gold surface leads to wrinkle formation and propagation at the interface. The periodic pattern is thought to be the result of an Asaro-Tiller-Grinfeld (ATG) instability.

  6. Nonlinear optical microscopy for imaging thin films and surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smilowitz, L.B.; McBranch, D.W.; Robinson, J.M.

    1995-03-01

    We have used the inherent surface sensitivity of second harmonic generation to develop an instrument for nonlinear optical microscopy of surfaces and interfaces. We have demonstrated the use of several nonlinear optical responses for imaging thin films. The second harmonic response of a thin film of C{sub 60} has been used to image patterned films. Two photon absorption light induced fluorescence has been used to image patterned thin films of Rhodamine 6G. Applications of nonlinear optical microscopy include the imaging of charge injection and photoinduced charge transfer between layers in semiconductor heterojunction devices as well as across membranes in biological systems.

  7. Inactivation of E. Coli in Water Using Photocatalytic, Nanostructured Films Synthesized by Aerosol Routes

    Directory of Open Access Journals (Sweden)

    Pratim Biswas

    2013-03-01

    Full Text Available TiO2 nanostructured films were synthesized by an aerosol chemical vapor deposition (ACVD method with different controlled morphologies: columnar, granular, and branched structures for the photocatalytic inactivation of Escherichia coli (E. coli in water. Effects of film morphology and external applied voltage on inactivation rate were investigated. As-prepared films were characterized using scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffractometry (XRD, and UV-VIS. Photocatalytic and photoelectrochemical inactivation of E. coli using as-prepared TiO2 films were performed under irradiation of UVA light (note: UVA has a low efficiency to inactivate E. coli. Inactivation rate constants for each case were obtained from their respective inactivation curve through a 2 h incubation period. Photocatalytic inactivation rate constants of E. coli are 0.02/min (using columnar films, and 0.08/min (using branched films. The inactivation rate constant for the columnar film was enhanced by 330% by applied voltage on the film while that for the branched film was increased only by 30%. Photocatalytic microbial inactivation rate of the columnar and the branched films were also compared taking into account their different surface areas. Since the majority of the UV radiation that reaches the Earth’s surface is UVA, this study provides an opportunity to use sunlight to efficiently decontaminate drinking water.

  8. Control on wetting properties of spin-deposited silica films by surface silylation method

    Energy Technology Data Exchange (ETDEWEB)

    Rao, A. Venkateswara, E-mail: avrao2012@gmail.com [Air Glass Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, Maharashtra (India); Latthe, Sanjay S.; Dhere, Sunetra L.; Pawar, Swapnali S. [Air Glass Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, Maharashtra (India); Imai, Hiroaki [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Ganesan, V. [CSR, Indore Centre, University Campus, Khandwa Road, Indore 452 017, Madhyapradesh (India); Gupta, Satish C.; Wagh, Pratap B. [Applied Physics Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai 400 085 (India)

    2010-01-15

    Control on the wettability of solid materials by liquid is a classical and key issue in surface engineering. Optically transparent water-repellent silica films have been spin-deposited on glass substrates at room temperature ({approx}27 deg. C). The wetting behavior of silica films was controlled by surface silylation method using dimethylchlorosilane (DMCS) as a silylating reagent. A coating sol was prepared by keeping the molar ratio of methyltrimethoxysilane (MTMS) precursor, methanol (MeOH) solvent, water (H{sub 2}O) constant at 1:8.8:2.64 respectively, with 4 M NH{sub 4}OH as a catalyst throughout the experiments and the amount of DMCS in hexane was varied from 0 to 12 vol.%. It was found that with an increase in vol.% of DMCS, the water contact angle values of the films increased from 78 deg. to 136 deg. At 12 vol.% of DMCS, the film shows static water contact angle as high as 136 deg. and water sliding angle as low as 18 deg. The hydrophobic silica films retained their water repellency up to a temperature 295 deg. C and above this temperature the films show superhydrophilic behavior. These results are compared with our earlier research work done on silylation of silica surface using hexamethyldisilazane (HMDZ) and trimethylchlorosilane (TMCS). The hydrophobic silica films were characterized by taking into consideration the Fourier transform infrared (FT-IR) spectroscopy, thermo gravimetric-differential thermal (TG-DT) analyses, scanning electron microscopy (SEM), atomic force microscopy (AFM), % of optical transmission, thermal and chemical aging tests, humidity tests, static and dynamic water contact angle measurements.

  9. Control on wetting properties of spin-deposited silica films by surface silylation method

    Science.gov (United States)

    Rao, A. Venkateswara; Latthe, Sanjay S.; Dhere, Sunetra L.; Pawar, Swapnali S.; Imai, Hiroaki; Ganesan, V.; Gupta, Satish C.; Wagh, Pratap B.

    2010-01-01

    Control on the wettability of solid materials by liquid is a classical and key issue in surface engineering. Optically transparent water-repellent silica films have been spin-deposited on glass substrates at room temperature (˜27 °C). The wetting behavior of silica films was controlled by surface silylation method using dimethylchlorosilane (DMCS) as a silylating reagent. A coating sol was prepared by keeping the molar ratio of methyltrimethoxysilane (MTMS) precursor, methanol (MeOH) solvent, water (H 2O) constant at 1:8.8:2.64 respectively, with 4 M NH 4OH as a catalyst throughout the experiments and the amount of DMCS in hexane was varied from 0 to 12 vol.%. It was found that with an increase in vol.% of DMCS, the water contact angle values of the films increased from 78° to 136°. At 12 vol.% of DMCS, the film shows static water contact angle as high as 136° and water sliding angle as low as 18°. The hydrophobic silica films retained their water repellency up to a temperature 295 °C and above this temperature the films show superhydrophilic behavior. These results are compared with our earlier research work done on silylation of silica surface using hexamethyldisilazane (HMDZ) and trimethylchlorosilane (TMCS). The hydrophobic silica films were characterized by taking into consideration the Fourier transform infrared (FT-IR) spectroscopy, thermo gravimetric-differential thermal (TG-DT) analyses, scanning electron microscopy (SEM), atomic force microscopy (AFM), % of optical transmission, thermal and chemical aging tests, humidity tests, static and dynamic water contact angle measurements.

  10. Nanopatterned articles produced using surface-reconstructed block copolymer films

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Thomas P.; Park, Soojin; Wang, Jia-Yu; Kim, Bokyung

    2016-06-07

    Nanopatterned surfaces are prepared by a method that includes forming a block copolymer film on a substrate, annealing and surface reconstructing the block copolymer film to create an array of cylindrical voids, depositing a metal on the surface-reconstructed block copolymer film, and heating the metal-coated block copolymer film to redistribute at least some of the metal into the cylindrical voids. When very thin metal layers and low heating temperatures are used, metal nanodots can be formed. When thicker metal layers and higher heating temperatures are used, the resulting metal structure includes nanoring-shaped voids. The nanopatterned surfaces can be transferred to the underlying substrates via etching, or used to prepare nanodot- or nanoring-decorated substrate surfaces.

  11. Experimental Study on Plasma Surface Treatment of Capacitors Film

    Science.gov (United States)

    Ling, Dai; Ting, Yin; Fuchang, Lin; Fei, Yan

    Plasma surface treatment is an optional way to change the electrical performance of the film capacitors used widely in pulse power application. This paper presents the experimental study of glow discharge plasma treatment to polyphenylene sulfide (PPS) film. By using infrared spectra and scanning electron microscope (SEM), the chemical component and microstructure of material surface has detected to be changed with different treatment strength and various discharge gas. After treatment, the film surface tends to be rougher and some sorts of polar radicals or groups found to be introduced. But there is no obvious change of the electrical strength of the film. At last, theoretical analysis has been carried out with polypropylene film experimental treatment results in author's former work.

  12. Superhydrophilic TiO2 thin film by nanometer scale surface roughness and dangling bonds

    Science.gov (United States)

    Bharti, Bandna; Kumar, Santosh; Kumar, Rajesh

    2016-02-01

    A remarkable enhancement in the hydrophilic nature of titanium dioxide (TiO2) films is obtained by surface modification in DC-glow discharge plasma. Thin transparent TiO2 films were coated on glass substrate by sol-gel dip coating method, and exposed in DC-glow discharge plasma. The plasma exposed TiO2 film exhibited a significant change in its wetting property contact angle, which is a representative of wetting property, has reduced to considerable limits 3.02° and 1.85° from its initial value 54.40° and 48.82° for deionized water and ethylene glycol, respectively. It is elucidated that the hydrophilic property of plasma exposed TiO2 films dependent mainly upon nanometer scale surface roughness. Variation, from 4.6 nm to 19.8 nm, in the film surface roughness with exposure time was observed by atomic force microscopy (AFM). Analysis of variation in the values of contact angle and surface roughness with increasing plasma exposure time reveal that the surface roughness is the main factor which makes the modified TiO2 film superhydrophilic. However, a contribution of change in the surface states, to the hydrophilic property, is also observed for small values of the plasma exposure time. Based upon nanometer scale surface roughness and dangling bonds, a variation in the surface energy of TiO2 film from 49.38 to 88.92 mJ/m2 is also observed. X-ray photoelectron spectroscopy (XPS) results show change in the surface states of titanium and oxygen. The observed antifogging properties are the direct results of the development of the superhydrophilic wetting characteristics to TiO2 films.

  13. The role of surface elasticity in liquid film formation

    Science.gov (United States)

    Champougny, Lorene; Scheid, Benoit; Restagno, Frederic; Rio, Emmanuelle; Laboratoire de Physique des Solides Team; TIPS-Fluid Physics Unit Team

    2014-11-01

    The formation of thin liquid films, either free standing (soap films) or deposited on a solid substrate (coated films), is of utmost importance for many applications, ranging from the control of foam stability to surface functionalization. In this work, the behavior of thin liquid films during their generation from a surfactant solution is investigated through comparison between a hydrodynamic model including surface elasticity and experiments. ``Twin'' models are proposed to describe the coating of films onto a solid plate (Landau-Levich-Derjaguin configuration) as well as soap film pulling (Frankel configuration) in a single framework. Experimental data are successfully fitted using the models, surface elasticity being the only adjustable parameter. For a given surfactant solution, the analyses of soap and coated films both yield the same value for the effective surface elasticity, showing that it is an intrinsic parameter of a surfactant solution. Conversely, we demonstrate that Frankel- or Landau-Levich-like experiments can be used in practice as surface rheometers to determine the numerical value of the (effective) surface elasticity of a solution, especially for values lower than those measurable by classical devices. L.C. was supported by ANR F2F. B.S. thanks the F.R.S.-FNRS for funding as well as the IAP-MicroMAST project.

  14. Weak nonlinear surface-charging effects in electrolytic films.

    Science.gov (United States)

    Dean, D S; Horgan, R R

    2003-11-01

    A simple model of soap films with nonionic surfactants stabilized by added electrolyte is studied. The model exhibits charge regularization due to the incorporation of a physical mechanism responsible for the formation of a surface charge. We use a Gaussian field theory in the film but the full nonlinear surface terms which are then treated at a one-loop level by calculating the mean-field Poisson-Boltzmann solution and then the fluctuations about this solution. We carefully analyze the renormalization of the theory and apply it to a triple-layer model for a thin film with Stern layer of thickness h. For this model we give expressions for the surface charge sigma(L) and the disjoining pressure P(d)(L) and show their dependence on the parameters. The influence of image charges naturally arises in the formalism, and we show that predictions depend strongly on h because of their effects. In particular, we show that the surface charge vanishes as the film thickness L-->0. The fluctuation terms in this class of theories contribute a Casimir-like attraction across the film. Although this attraction is well known to be negligible compared with the mean-field component for model electrolytic films with no surface-charge regulation, in the model studied here these fluctuations also affect the surface-charge regulation leading to a fluctuation component in the disjoining pressure which has the same behavior as the mean-field component even for large film thickness.

  15. New insight into surface properties of LB film of an amphiphilic terpolymer

    Institute of Scientific and Technical Information of China (English)

    Xiu Li Yue; Fang Ma; Zhi Fei Dai; Meng Liu; Lei Xing; Hai Yan Fan; Zhan Wen Xing; Shao Qin Liu

    2011-01-01

    Amphiphilic terpolymer (TPR) exhibits good film-forming behavior on pure water observed by means of n-A isotherms. To gain insight into physical properties of TPR, the films have been deposited on silicon substrates at different surface pressure by Langmuir-Blodgett (LB) technique. It was found that the increase in peak intensities of stretching mode was due to orderly packing of the films. The contact angles increased with increasing surface pressure, indicating an increase in hydrophobicity due to dense packing of chains of TPR. The cyclic voltammetric measurements indicated that TPR showed good current shielding effect for electron-transfer. In a word, LB films of TPR can produce a variety of structures with varied topography, enabling us to control not only the functionality of the surface, but also the interfacial transport characteristics.

  16. A novel collagen film with micro-rough surface structure for corneal epithelial repair fabricated by freeze drying technique

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 (China); Ren, Li, E-mail: psliren@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 (China); Wang, Yingjun, E-mail: imwangyj@163.com [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 (China)

    2014-05-01

    Highlights: • Collagen film with micro-rough surface is fabricated by freeze drying technique. • The film has suitable water uptake capability and toughness performance. • The film has good optical performance. • Human corneal epithelial cells studies confirmed the biocompatibility of the film. - Abstract: Corneal epithelial defect is a common disease and keratoplasty is a common treatment method. A collagen film with micro-rough surface was fabricated through a simple freeze drying technique in this study. Compared with the air-dried collagen film (AD-Col), this freeze-dried collagen film (FD-Col) has a more suitable water uptake capability (about 85.5%) and toughness performance. Both of the two films have good optical properties and the luminousness of them is higher than 80%. Besides, the adhesion and proliferation rate of human corneal epithelial cells on the micro-rough surface of FD-Col film is higher than that on the smooth surface of AD-Col film. The results indicate that this FD-Col film may have potential applications for corneal epithelial repair.

  17. Environmental stability of solution processed Al-doped ZnO naoparticulate thin films using surface modification technique

    Science.gov (United States)

    Vunnam, Swathi; Ankireddy, Krishnamraju; Kellar, Jon; Cross, William

    2014-12-01

    The environmental stability of solution processed Al-doped ZnO (AZO) thin films was enhanced by functionalizing the film surface with a thin self-assembled molecular layer. Functionalization of AZO films was performed using two types of molecules having identical 12-carbon alkyl chain termination but different functional groups: dodecanethiol (DDT) and dodecanoic acid (DDA). Surface modified AZO films were examined using electrical resistivity measurements, contact angle measurements and quantitative nanomechanical property mapping atomic force microscopy. The hydrophobic layer inhibits the penetration of oxygen and water into the AZO's grain boundaries thus significantly increasing the environmental stability over unmodified AZO. Surface modified AZO films using DDT exhibited lower electrical resistivity compared to DDA functionalized AZO films. Our study demonstrates a new approach for improving the physical properties of oxide based nanoparticulate films for device applications.

  18. Use of New Water Soluble Surface Film—Forming Material to Reduce Ammonia Loss from Water Solution

    Institute of Scientific and Technical Information of China (English)

    YINBIN; SHENRENFANG; 等

    1996-01-01

    A new water soluble surface film-forming material was developed and its effect on reducing ammonia volatilization from an alkaline solution was investigated in laboratory,Results showed that the new film formed by the material was not only more effective in reducing ammonia loss than any other films tested but also much cheaper.The optimum amount of addition of the new film-forming material was about 10times the theoretical amount to form a monomolecular film.Under the experimental conditions,the new film could effectively depress the ammonia volatilization for at least 6 days.The cumulative ammonia loss rates for different films were fitted to a simple logistic equation ,and some important parameters such as the cumulative loss,and the maximum and average volatilization rates were calculated.The effect of different films could be,therefore,compared quantitatively,indicating the new film was most effective in depressing ammonia volatilization.

  19. Spin-Casting Polymer Brush Films for Stimuli-Responsive and Anti-Fouling Surfaces.

    Science.gov (United States)

    Xu, Binbin; Feng, Chun; Hu, Jianhua; Shi, Ping; Gu, Guangxin; Wang, Lei; Huang, Xiaoyu

    2016-03-01

    Surfaces modified with amphiphilic polymers can dynamically alter their physicochemical properties in response to changes of their environmental conditions; meanwhile, amphiphilic polymer coatings with molecular hydrophilic and hydrophobic patches, which can mitigate biofouling effectively, are being actively explored as advanced coatings for antifouling materials. Herein, a series of well-defined amphiphilic asymmetric polymer brushes containing hetero side chains, hydrophobic polystyrene (PS) and hydrophilic poly(ethylene glycol) (PEG), was employed to prepare uniform thin films by spin-casting. The properties of these films were investigated by water contact angle, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and quartz crystal microbalance (QCM). AFM showed smooth surfaces for all films with the roughness less than 2 nm. The changes in water contact angle and C/O ratio (XPS) evidenced the enrichment of PEG or PS chains at film surface after exposed to selective solvents, indicative of stimuli- responsiveness. The adsorption of proteins on PEG functionalized surface was quantified by QCM and the results verified that amphiphilic polymer brush films bearing PEG chains could lower or eliminate protein-material interactions and resist to protein adsorption. Cell adhesion experiments were performed by using HaCaT cells and it was found that polymer brush films possess good antifouling ability.

  20. Honeycomb-patterned films of polystyrene/poly(ethylene glycol): Preparation, surface aggregation and protein adsorption

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Highly ordered honeycomb-patterned polystyrene (PS)/poly(ethylene glycol) (PEG) films were prepared by a water-assisted method using an improved setup, which facilitated the formation of films with higher regularity, better reproducibility, and larger area of honeycomb structures. Surface aggregation of hydrophilic PEG and adsorption of bovine serum albumin (BSA) on the honeycomb-patterned films were investigated. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to observe the surface morphologies of the films before and after being rinsed with water. As confirmed by the FESEM images and the AFM phase images, PEG was enriched in the pores and could be gradually removed by water. The adsorption of fluorescence-labeled BSA on the films was studied in visual form using laser scanning confocal microscopy. Results clearly demonstrated that the protein-resistant PEG was selectively enriched in the pores. This water-assisted method may be a latent tool to prepare honeycomb-patterned biofunctional surfaces.

  1. Light irradiation tuning of surface wettability, optical, and electric properties of graphene oxide thin films

    Science.gov (United States)

    Furio, A.; Landi, G.; Altavilla, C.; Sofia, D.; Iannace, S.; Sorrentino, A.; Neitzert, H. C.

    2017-02-01

    In this work the preparation of flexible polymeric films with controlled electrical conductivity, light transmission and surface wettability is reported. A drop casted graphene oxide thin film is photo-reduced at different levels by UV light or laser irradiation. Optical microscopy, IR spectroscopy, electrical characterization, Raman spectroscopy and static water contact angle measurements are used in order to characterize the effects of the various reduction methods. Correlations between the optical, electrical and structural properties are reported and compared to previous literature results. These correlations provide a useful tool for independently tuning the properties of these films for specific applications.

  2. Scale-up of water-based spider silk film casting using a film applicator.

    Science.gov (United States)

    Agostini, Elisa; Winter, Gerhard; Engert, Julia

    2017-08-24

    Spider silk proteins for applications in drug delivery have attracted an increased interest during the past years. Some possible future medical applications for this biocompatible and biodegradable material are scaffolds for tissue engineering, implantable drug delivery systems and coatings for implants. Recently, we reported on the preparation of water-based spider silk films for drug delivery applications. In the current study, we describe the development of a manufacturing technique for casting larger spider silk films from aqueous solution employing a film applicator. Films were characterized in terms of morphology, water solubility, protein secondary structure, thermal stability, and mechanical properties. Different post-treatments were evaluated (phosphate ions, ethanol, steam sterilization and water vapor) to increase the content of β-sheets thereby achieving water insolubility of the films. Finally, the mechanical properties of the spider silk films were improved by incorporating 2-pyrrolidone as plasticizer. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Study of Hydrogen flame annealed Au thin-film surface morphology, integrity and film quality on various substrate surfaces

    Science.gov (United States)

    Schell, Michael; Senevirathne, Indrajith

    2013-03-01

    Au thin-films have many applications in both industry and proof of concept investigations in device engineering. Typical Au depositions on substrate give rise to Stanski-Krastanov (SK) like growth while Frank-van der Merwe (FM) mode like growth is desired in many molecular self assembly and other engineering applications. Au films are magnetron sputter deposited at 100mtorr at low deposition rates (~ 1ML/min) on cleaved/fresh mica, glass microscopy slides and Si surfaces. Samples are hydrogen flame annealed to facilitate surface diffusion with minimal film contamination. Resulting Au surfaces were investigated and compared against purchased Au(111) on mica (standard) surface. Regular and custom built hydrophilic and hydrophobic AFM (Atomic Force Microcopy) probes were used in contact, and non contact AFM with topography and phase imaging to access the contamination and surface defects. Surface integrity, roughness, corrugation and morphology on Au surfaces were estimated. LHU Nanotechnology Program, PASSHE FPDC (LOU # 2010-LHU-03).

  4. Ethanol-assisted graphene oxide-based thin film formation at pentane-water interface.

    Science.gov (United States)

    Chen, Fuming; Liu, Shaobin; Shen, Jianmin; Wei, Li; Liu, Andong; Chan-Park, Mary B; Chen, Yuan

    2011-08-02

    Graphene oxide (GO) can be viewed as an amphiphilic soft material, which form thin films at organic solvent-water interfaces. However, organic solvent evaporation provides little driving force, which results in slow GO transfer in aqueous phase, thus dawdling GO film formation processes for various potential applications. We present an ethanol-assisted self-assembly method for the quick formation of GO or GO-based composite thin films with tunable composition, transmittance, and surface resistivity at pentane-water interface. The thickness of pure GO and reduced GO (rGO) films ranging from ~1 nm to more than 10 nm can be controlled by the concentration of GO in bulk solution. The transmittance of rGO films can be tuned from 72% to 97% at 550 nm while the surface resistivity changes from 8.3 to 464.6 kΩ sq(-1). Ethanol is essential for achieving quick formation of GO thin films. When ethanol is injected into GO aqueous dispersion, it serves as a nonsolvent, compromising the stability of GO and providing driving force to allow GO sheets aggregate at the water-pentane interface. On the other hand, neither the evaporation of pentane nor the mixing between ethanol and water provides sufficient driving forces to allow noteworthy amount of GO sheets to migrate from the bulk aqueous phase to the interface. This method can also be extended to prepare GO-based composites thin films with tunable composition, such as GO/single walled carbon nanotube (SWCNT) composite thin films investigated in this work. Reduced GO/SWCNT composite films show much lower surface resistivity compared to pure rGO thin films. This ethanol-assisted self-assembly method opens opportunities to design and fabricate new functional GO-based hybrid materials for various potential applications.

  5. Water repellent porous silica films by sol-gel dip coating method.

    Science.gov (United States)

    Rao, A Venkateswara; Gurav, Annaso B; Latthe, Sanjay S; Vhatkar, Rajiv S; Imai, Hiroaki; Kappenstein, Charles; Wagh, P B; Gupta, Satish C

    2010-12-01

    The wetting of solid surfaces by water droplets is ubiquitous in our daily lives as well as in industrial processes. In the present research work, water repellent porous silica films are prepared on glass substrate at room temperature by sol-gel process. The coating sol was prepared by keeping the molar ratio of methyltriethoxysilane (MTES), methanol (MeOH), water (H(2)O) constant at 1:12.90:4.74, respectively, with 2M NH(4)OH throughout the experiments and the molar ratio (M) of MTES/Ph-TMS was varied from 0 to 0.22. A simple dip coating technique is adopted to coat silica films on the glass substrates. The static water contact angle as high as 164° and water sliding angle as low as 4° was obtained for silica film prepared from M=0.22. The surface morphological studies of the prepared silica film showed the porous structure with pore sizes typically ranging from 200nm to 1.3μm. The superhydrophobic silica films prepared from M=0.22 retained their superhydrophobicity up to a temperature of 285°C and above this temperature the films became superhydrophilic. The porous and water repellent silica films are prepared by proper alteration of the Ph-TMS in the coating solution. The prepared silica films were characterized by surface profilometer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform Infrared (FT-IR) spectroscopy, humidity tests, chemical aging tests, static and dynamic water contact angle measurements.

  6. Study on the effect of subcooling on vapor film collapse on high temperature particle surface

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Yutaka; Tochio, Daisuke; Yanagida, Hiroshi [Department of Mechanical Systems Engineering, Yamagata Univ., Yonezawa, Yamagata (Japan)

    2000-11-01

    Thermal detonation model is proposed to describe vapor explosion. According to this model, vapor film on pre-mixed high temperature droplet surface is needed to be collapsed for the trigger of the vapor explosion. It is pointed out that the vapor film collapse behavior is significantly affected by the subcooling of low temperature liquid. However, the effect of subcooling on micro-mechanism of vapor film collapse behavior is not experimentally well identified. The objective of the present research is to experimentally investigate the effect of subcooling on micro-mechanism of film boiling collapse behavior. As the results, it is experimentally clarified that the vapor film collapse behavior in low subcooling condition is qualitatively different from the vapor film collapse behavior in high subcooling condition. In case of vapor film collapse by pressure pulse, homogeneous vapor generation occurred all over the surface of steel particle in low subcooling condition. On the other hand, heterogeneous vapor generation was observed for higher subcooling condition. In case of vapor film collapse spontaneously, fluctuation of the gas-liquid interface after quenching propagated from bottom to top of the steel particle heterogeneously in low subcooling condition. On the other hand, simultaneous vapor generation occurred for higher subcooling condition. And the time transient of pressure, particle surface temperature, water temperature and visual information were simultaneously measured in the vapor film collapse experiment by external pressure pulse. Film thickness was estimated by visual data processing technique with the pictures taken by the high-speed video camera. Temperature and heat flux at the vapor-liquid interface were estimated by solving the heat condition equation with the measured pressure, liquid temperature and vapor film thickness as boundary conditions. Movement of the vapor-liquid interface were estimated with the PIV technique with the visual observation

  7. Poly(acrylic acid surface grafted polypropylene films: Near surface and bulk mechanical response

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available Radical photo-grafting polymerization constitutes a promising technique for introducing functional groups onto surfaces of polypropylene films. According to their final use, surface grafting should be done without affecting overall mechanical properties. In this work the tensile drawing, fracture and biaxial impact response of biaxially oriented polypropylene commercial films grafted with poly(acrylic acid (PAA were investigated in terms of film orientation and surface modification. The variations of surface roughness, elastic modulus, hardness and resistance to permanent deformation induced by the chemical treatment were assessed by depth sensing indentation. As a consequence of chemical modification the optical, transport and wettability properties of the films were successfully varied. The introduced chains generated a PAA-grafted layer, which is stiffer and harder than the neat polypropylene surface. Regardless of the surface changes, it was proven that this kind of grafting procedure does not detriment bulk mechanical properties of the PP film.

  8. Tribological thin films on steel rolling element bearing surfaces

    Science.gov (United States)

    Evans, Ryan David

    Tribological thin films are of interest to designers and end-users of friction management and load transmission components such as steel rolling element bearings. This study sought to reveal new information about the properties and formation of such films, spanning the scope of their technical evolution from natural oxide films, to antiwear films from lubricant additives, and finally engineered nanocomposite metal carbide/amorphous hydrocarbon (MC/a-C:H) films. Transmission electron microscopy (TEM) was performed on the near-surface material (depth gear oil additives. Site-specific thinning of cross-section cone surface sections for TEM analyses was conducted using the focused ion beam milling technique. Two types of oxide surface films were characterized for the cones tested in mineral oil only, each one corresponding to a different lubrication severity. Continuous and adherent antiwear films were found on the cone surfaces tested with lubricant additives, and their composition depended on the lubrication conditions. A sharp interface separated the antiwear film and base steel. Various TEM analytical techniques were used to study the segregation of elements throughout the film volume. The properties of nanocomposite tantalum carbide/amorphous hydrocarbon (TaC/a-C:H) thin films depend sensitively on reactive magnetron sputtering deposition process conditions. TaC/a-C:H film growth was studied as a function of three deposition parameters in designed experiments: acetylene flow rate, applied d.c. bias voltage, and substrate carousel rotation rate. Empirical models were developed for the following film characteristics to identify process-property trend relationships: Ta/C atomic ratio, hydrogen content, film thickness. TaC crystallite size, Raman spectrum, compressive stress, hardness, and elastic modules. TEM measurements revealed the film base structure consisted of equiaxed cubic B1-TaC crystallites (< 5 nm) suspended in an a-C:H matrix. At the nanometer-scale, the

  9. Water molecules orientation in surface layer

    Science.gov (United States)

    Klingo, V. V.

    2000-08-01

    The water molecules orientation has been investigated theoretically in the water surface layer. The surface molecule orientation is determined by the direction of a molecule dipole moment in relation to outward normal to the water surface. Entropy expressions of the superficial molecules in statistical meaning and from thermodynamical approach to a liquid surface tension have been found. The molecules share directed opposite to the outward normal that is hydrogen protons inside is equal 51.6%. 48.4% water molecules are directed along to surface outward normal that is by oxygen inside. A potential jump at the water surface layer amounts about 0.2 volts.

  10. Surface modification by plasma polymerization: film deposition, tailoring of surface properties and biocompatibility

    OpenAIRE

    Os, van, J.

    2000-01-01

    The work described in this thesis concerns the surface modification of materials by thin film deposition in a plasma reactor. In particular, thin polymeric films bearing amine functionalities were synthesized by plasma polymerization of amino group containing monomers. In addition to the synthesis, attention was directed towards the characterization of these films, and the tailoring of their surface properties on a molecular level. Finally, the amino groups introduced by plasma polymerization...

  11. Surface Morphology of Undoped and Doped ZnSe Films

    Science.gov (United States)

    George, T.; Hayes, M.; Chen, H.; Chattopadhyay, K.; Thomas E.; Morgan, S.; Burger, A.

    1998-01-01

    Rare-earth doped ions in polar II-VI semiconductors have recently played an important role in the optical properties of materials and devices. In this study, undoped ZnSe and erbium doped ZnSe films were grown by radio frequency (RF) magnetron sputtering method. Atomic Force Microscopy (AFM) was used together with optical microscopy and UV-Vis spectroscopy to characterize the films. Doped samples were found to have higher surface roughness and quite different surface morphology compared to that of undoped samples. The grown films generally show a relatively smooth and uniform surface indicating that they are of overall good quality. The impact of plasma etching on ZnSe:Er film examined under AFM is also discussed.

  12. Nonlocal effect in surface plasmon polariton of ultrathin metal films

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Hong-jie; Yu, Yabin, E-mail: apybyu@hnu.edu.cn; Wu, Reng-lai; Yu, Yan-qin; Wang, Ya-xin

    2015-09-01

    Using the nonlocal conductivity based on quantum response theory, we study the optical properties of p-polarized wave in quartz–metal–film–air structures, especially the influence of nonlocal effect on the surface plasmon polaritons (SPPs) resonance. In absorption spectrum, the resonant peak of SPP is found, and the dependence of the resonant peak on film thickness shows that nonlocal effect in the SPP resonance is enhanced significantly with the decrease of film-thickness, especially in the less than 20 nm metal film. We calculate the surface charge density as a function of frequency, and find that the frequencies at the charge and absorption peaks are the same. This clearly confirms that the absorption peak stems from SPP resonance excitation, and SPPs absorb the energy of the electromagnetic wave via charge oscillations. In the case of SPP resonance, the charge and electric field on the down-surface of thin film are always greater than that on the up-surface; however, the situation is just opposite in the case of no SPP resonance. This implies that the SPP resonance occurs near the down-surface of the film. Moreover, due to the nonlocal response of electric current to the electric field, the energy flow and electric current show anomalous oscillations, and with the increase of film thickness the anomalous oscillations exhibit obvious attenuation.

  13. Water Vapor Permeation of Metal Oxide/Polymer Coated Plastic Films

    Science.gov (United States)

    Numata, Yukihiro; Oya, Toshiyuki; Kuwahara, Mitsuru; Ito, Katsuya

    Barrier performance to water vapor permeation of ceramic coated layers deposited on flexible polymer films is of great interest to food packaging, medical device packaging and flat panel display industries. In this study, a new type film in which a ceramic layer is deposited on a polymer coated film was proposed for lower water vapor permeation. It is important how to control interfacial properties between each layer and film for good barrier performance. Several kinds of polymer coated materials were prepared for changing surface free energy of the films before and after depositing the ceramic layer. The ceramic layer, which is composed of mixed material of SiO2 and Al2O3, was adopted under the same conditions. The following results were obtained; 1) Water vapor permeation is not related to the surface energy of polymer coated films, 2) After depositing the ceramic layer, however, a strong correlation is observed between the water vapor permeation and surface free energy. 3) The phenomenon is considered that the polarity of the polymer layers plays a key role in changing the structure of ceramic coated layers.

  14. Surface morphology of thin lysozyme films produced by matrix-assisted pulsed laser evaporation (MAPLE)

    DEFF Research Database (Denmark)

    Purice, Andreea; Schou, Jørgen; Pryds, Nini;

    2007-01-01

    Thin films of the protein, lysozyme, have been deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. Frozen targets of 0.3-1.0 wt.% lysozyme dissolved in ultrapure water were irradiated by laser light at 355 mn with a fluence of 2 J/cm(2). The surface quality of the thin ly...

  15. Modelling global fresh surface water temperature

    NARCIS (Netherlands)

    Beek, L.P.H. van; Eikelboom, T.; Vliet, M.T.H. van; Bierkens, M.F.P.

    2011-01-01

    Temperature directly determines a range of water physical properties including vapour pressure, surface tension, density and viscosity, and the solubility of oxygen and other gases. Indirectly water temperature acts as a strong control on fresh water biogeochemistry, influencing sediment

  16. Modelling global fresh surface water temperature

    NARCIS (Netherlands)

    Beek, L.P.H. van; Eikelboom, T.; Vliet, M.T.H. van; Bierkens, M.F.P.

    2011-01-01

    Temperature directly determines a range of water physical properties including vapour pressure, surface tension, density and viscosity, and the solubility of oxygen and other gases. Indirectly water temperature acts as a strong control on fresh water biogeochemistry, influencing sediment concentrati

  17. Superhydrophilic surface treatment for thin film NiTi vascular applications

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Youngjae, E-mail: yjchun@ucla.edu [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 32-135, Engineering IV, Los Angeles, CA 90095 (United States); Levi, Daniel S., E-mail: dlevi@ucla.edu [Pediatric Cardiology, Mattel Children' s Hospital, UCLA, B2-427, 10833 Le Conte Avenue, Los Angeles, CA 90095-1743 (United States); Mohanchandra, K.P., E-mail: kpmohan@seas.ucla.edu [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 32-135, Engineering IV, Los Angeles, CA 90095 (United States); Carman, Gregory P., E-mail: carman@seas.ucla.edu [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 38-137M, Engineering IV, Los Angeles, CA 90095 (United States)

    2009-10-15

    A variety of surface treatment methods were evaluated to modify the hydrophilic nature of thin film nitinol (NiTi). It has been suggested that increasing hydrophilicity reduces the prevalence of platelet adhesion and thrombosis in the vascular system. In this study, thin film NiTi was treated with three pretreatments cleaning, buffered oxide etchant (BOE), and BOE/nitric acid (HNO{sub 3}), followed by one surface treatment. The three surface treatment studied were UV irradiation, thermal treatment, or hydrogen peroxide. Two surface treatments, i.e., thermal at 600 deg. C for 30 min and 30% hydrogen peroxide treatment for 15 h, produced superhydrophilic surfaces, i.e., wetting angle = 0 deg. However, the superhydrophilic surface produced by the thermal treatment also embrittled the thin film due to the relative thickness of the oxide grown. Long term studies in air showed that all surface treatments trend toward hydrophobic natures. However, storage of the surface treated thin film NiTi in Deionized (DI) water preserved even the superhydrophilic surfaces indefinitely.

  18. Rocky Mountain Arsenal surface water management plan : water year 2003

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Surface Water Management Plan (SWMP) for Water Year 2003 (WY 2003) (October I, 2002 to September 30, 2003) is an assessment of the nonpotable water demands at...

  19. Rocky Mountain Arsenal surface water management plan : water year 2005

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Surface Water Management Plan for Water Year (WY) 2005 (October 1, 2004 to September 30, 2005) is an assessment of the nonpotable water demands at the Rocky...

  20. Rocky Mountain Arsenal surface water management plan : water year 2006

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Surface Water Management Plan for Water Year (WY) 2006 (October 1, 2005 to September 30, 2006) is an assessment of the nonpotable water demands at the Rocky...

  1. Surface roughness evolution of nanocomposite thin films

    NARCIS (Netherlands)

    Turkin, A; Pei, Y.T.; Shaha, K.P.; Chen, C.Q.; Vainchtein, David; Hosson, J.Th.M. De

    2009-01-01

    An analysis of dynamic roughening and smoothening mechanisms of thin films grown with pulsed-dc magnetron sputtering is presented. The roughness evolution has been described by a linear stochastic equation, which contains the second- and fourth-order gradient terms. Dynamic smoothening of the growin

  2. pH-controllable water permeation through a nanostructured copper mesh film.

    Science.gov (United States)

    Cheng, Zhongjun; Du, Ming; Fu, Kewei; Zhang, Naiqing; Sun, Kening

    2012-11-01

    Water permeation is an important issue in both fundamental research and industrial applications. In this work, we report a novel strategy to realize the controllable water permeation on the mixed thiol (containing both alkyl and carboxylic acid groups) modified nanostructured copper mesh films. For acidic and neutral water, the film is superhydrophobic, and the water cannot permeate the film because of the large negative capillary effect resulting from the nanostructures. For basic water, the film shows superhydrophilic property, and thus the water can permeate the film easily. The permeation process of water can be controlled just by simply altering the water pH. A detailed investigation indicates that nanostructures on the substrate and the appropriate size of the microscale mesh pores can enhance not only the static wettability but also the dynamic properties. The excellent controllability of water permeation is ascribed to the combined effect of the chemical variation of the carboxylic acid group and the microstructures on the substrate. This work may provide interesting insight into the new applications that are relevant to the surface wettability, such as filtration, microfluidic device, and some separation systems.

  3. Surface water discharges from onshore stripper wells.

    Energy Technology Data Exchange (ETDEWEB)

    Veil, J. A.

    1998-01-16

    Under current US Environmental Protection Agency (EPA) rules, small onshore oil producers are allowed to discharge produced water to surface waters with approval from state agencies; but small onshore gas producers, however, are prohibited from discharging produced water to surface waters. The purpose of this report is to identify those states that allow surface water discharges from small onshore oil operations and to summarize the types of permitting controls they use. It is intended that the findings of this report will serve as a rationale to encourage the EPA to revise its rules and to remove the prohibition on surface water discharges from small gas operations.

  4. Surface structures from low energy electron diffraction: Atoms, small molecules and an ordered ice film on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Materer, N.F.

    1995-09-01

    We investigated the surface bonding of various adsorbates (0, S, C{sub 2}H{sub 3} and NO) along with the resulting relaxation of the Pt(111) surface using low energy electron diffiraction (LEED). LEED experiments have been performed on these ordered overlayers along with theoretical structural analysis using automated tensor LEED (ATLEED). The resulting surface structures of these ordered overlayers exhibit similar adsorbate-induced relaxations. In all cases the adsorbate occupies the fcc hollow site and induces an approximately 0.1 A buckling of the metal surface. The three metal atoms directly bonded to the adsorbate are ``pulled`` out of the surface and the metal atom that is not bound to the adsorbate is `pushed`` inward. In order to understand the reliability of such details, we have carried out a comprehensive study of various non-structural parameters used in a LEED computation. We also studied the adsorption of water on the Pt(lll) surface. We ordered an ultra thin ice film on this surface. The film`s surface is found to be the (0001) face of hexagonal ice. This surface is apparently terminated by a full-bilayer, in which the uppermost water molecules have large vibrational amplitudes even at temperatures as low as 90 K. We examined two other metal surfaces besides Pt(111): Ni(111) and Fe(lll). On Ni(111), we have studied the surface under a high coverage of NO. On both Ni(111) and Pt(111) NO molecules occupy the hollow sites and the N-0 bond distances are practically identical. The challenging sample preparation of an Fe(111) surface has been investigated and a successful procedure has been obtained. The small interlayer spacing found on Fe(111) required special treatment in the LEED calculations. A new ATLEED program has been developed to handle this surface.

  5. SURFACE MODIFICATION OF TITANIUM FILMS WITH SODIUM ION IMPLANTATION: SURFACE PROPERTIES AND PROTEIN ADSORPTION

    Institute of Scientific and Technical Information of China (English)

    K. Y. Cai

    2007-01-01

    Sodium implanted titanium films with different ion doses were characterized to correlate their ion implantation parameters. Native titanium films and ion implanted titanium films were characterized with combined techniques of X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and light microscopy (LM). The surface presented increased sodium concentration on treated titanium films with ion dose increasing, except for the group with the highest ion dose of 4× 1017 ions/cm2. XPS depth profiling displayed that sodium entered titanium film around 25-50 nm depth depending on its implantation ion dose. AFM characterization showed that sodium ion implantation treatment changed the surface morphology from a relatively smooth titanium film to rough surfaces corresponding to different implantation doses.After sodium implantation, implanted titanium films presented big particles with island structure morphology. The surface morphology and particle growth displayed the corresponding trend.Fibrinogen adsorption on these titanium films was performed to correlate with the surface properties of treated titanium films. The results show that protein adsorption on ion-implanted samples with dose of 2 × 1017 and 4 × 1017 are statistically higher (p < 0. 01) than samples treated with dose of 5×1016 and 1 ×1017, as well as the control samples.

  6. A scattering model for surface-textured thin films

    NARCIS (Netherlands)

    Jäger, K.; Zeman, M.

    2009-01-01

    We present a mathematical model that relates the surface morphology of randomly surface-textured thin films with the intensity distribution of scattered light. The model is based on the first order Born approximation [see e.g., M. Born and E. Wolf, Principles of Optics, 7th ed. (Cambridge University

  7. Factors affecting surface and release properties of thin PDMS films

    DEFF Research Database (Denmark)

    Vudayagiri, Sindhu; Junker, Michael Daniel; Skov, Anne Ladegaard

    2013-01-01

    of perfluoroether allylamide (PFE) lowered the surface energy which could ease the release. This is further investigated together with an evaluation of the resulting change in actuator performance. The relationship between the adhesive energy, surface energy, Young’s modulus and peel force of the films is analyzed....

  8. A scattering model for surface-textured thin films

    NARCIS (Netherlands)

    Jäger, K.; Zeman, M.

    2009-01-01

    We present a mathematical model that relates the surface morphology of randomly surface-textured thin films with the intensity distribution of scattered light. The model is based on the first order Born approximation [see e.g., M. Born and E. Wolf, Principles of Optics, 7th ed. (Cambridge University

  9. Influence of Annealing Temperature on CZTS Thin Film Surface Properties

    Science.gov (United States)

    Feng, Wenmei; Han, Junfeng; Ge, Jun; Peng, Xianglin; Liu, Yunong; Jian, Yu; Yuan, Lin; Xiong, Xiaolu; Cha, Limei; Liao, Cheng

    2017-01-01

    In this work, copper zinc tin sulfide (CZTS) films were deposited by direct current sputtering and the samples were annealed in different oven-set temperatures and atmosphere (Ar and H2S). The surface evolution was investigated carefully by using scanning electron microscopy (SEM), Raman spectroscopy and x-ray photoelectron spectroscopy. The surface of the as-sputtered precursor contained little Cu and large amounts of Zn and Sn. The metallic precursor was continuous and compact without pinholes or cracks. With the increase of the temperature from room temperature to 250°C, Cu atoms diffused to the film surface to form Cu1- x S and covered other compounds. Some small platelets were smaller than 500 nm spreading randomly in the holes of the film surfaces. When the temperature reached 350°C, Zn and Sn atoms began to diffuse to the surface and react with S or Cu1- x S. At 400°C, SEM showed the melting of large particles and small particles with a size from 100 nm to 200 nm in the background of the film surface. Excess Zn segregated towards the surface regions and formed ZnS phase on the surface. In addition, the signal of sodium in the CZTS surface was observed above 400°C. At 600°C, a large amount of regular structures with clear edges and corners were observed in the film surface in SEM images. A clear recrystallized process on the surface was assumed from those observations.

  10. On near-free-surface dynamics of thin polymer films

    Science.gov (United States)

    Qi, Dongping

    In the present studies of four projects we developed several novel techniques to investigate near-free-surface dynamics of thin polymer films. In the first project, we studied the dynamical properties of the first 2-3 nm region of glassy isotactic poly (methyl methacrylate) (i-PMMA) films by means of the nano surface hole relaxation technique. We found that for the measured surface relaxation times there is a strong substrate property dependence, which can propagate into i-PMMA films for a distance of more than 100nm. An unexpected molecular weight (Mw) dependence of the near surface relaxation time is found for thick i-PMMA films, which, together with the finding that the free surface could be assigned a local surface glass transition temperature of ˜40K below bulk T g, indicates a viscous liquid regime while the rest of the underneath bulk part is in the glassy state. In the second project, the nano gold sphere embedding technique was used to study the nearfree-surface dynamics of polystyrene (PS) films within wide temperature and time windows. Three sections of measurements are conducted in this project. In the first section, we studied the Mw dependence of the near-free-surface dynamics of PS films and found that at temperatures above bulk Tg there exists a Mw dependence which can be explained using the Rouse dynamics for melt polymers. However, at a temperature of 16K below bulk T g no w M dependence is discernible, which is in contrast to that for i-PMMA films where even at a temperature of ˜36K below bulk Tg a Mw dependence of the near free surface dynamics is still observed. In the second section of this work, we studied the nano gold sphere embedding behavior within a wide temperature and time window, and for the first time the depth dependence of the near-free-surface dynamics with the nanometer scale resolution was observed. By an embedding-model-free data analysis the results show that when the measurement temperature is above a temperature of ˜378K

  11. TiO2 and Fe2O3 films for photoelectrochemical water splitting.

    Science.gov (United States)

    Krysa, Josef; Zlamal, Martin; Kment, Stepan; Brunclikova, Michaela; Hubicka, Zdenek

    2015-01-09

    Titanium oxide (TiO2) and iron oxide (α-Fe2O3) hematite films have potential applications as photoanodes in electrochemical water splitting. In the present work TiO2 and α-Fe2O3 thin films were prepared by two methods, e.g., sol-gel and High Power Impulse Magnetron Sputtering (HiPIMS) and judged on the basis of physical properties such as crystalline structure and surface topography and functional properties such as simulated photoelectrochemical (PEC) water splitting conditions. It was revealed that the HiPIMS method already provides crystalline structures of anatase TiO2 and hematite Fe2O3 during the deposition, whereas to finalize the sol-gel route the as-deposited films must always be annealed to obtain the crystalline phase. Regarding the PEC activity, both TiO2 films show similar photocurrent density, but only when illuminated by UV light. A different situation was observed for hematite films where plasmatic films showed a tenfold enhancement of the stable photocurrent density over the sol-gel hematite films for both UV and visible irradiation. The superior properties of plasmatic film could be explained by ability to address some of the hematite drawbacks by deposition of very thin films (25 nm) consisting of small densely packed particles and by doping with Sn.

  12. TiO2 and Fe2O3 Films for Photoelectrochemical Water Splitting

    Directory of Open Access Journals (Sweden)

    Josef Krysa

    2015-01-01

    Full Text Available Titanium oxide (TiO2 and iron oxide (α-Fe2O3 hematite films have potential applications as photoanodes in electrochemical water splitting. In the present work TiO2 and α-Fe2O3 thin films were prepared by two methods, e.g., sol-gel and High Power Impulse Magnetron Sputtering (HiPIMS and judged on the basis of physical properties such as crystalline structure and surface topography and functional properties such as simulated photoelectrochemical (PEC water splitting conditions. It was revealed that the HiPIMS method already provides crystalline structures of anatase TiO2 and hematite Fe2O3 during the deposition, whereas to finalize the sol-gel route the as-deposited films must always be annealed to obtain the crystalline phase. Regarding the PEC activity, both TiO2 films show similar photocurrent density, but only when illuminated by UV light. A different situation was observed for hematite films where plasmatic films showed a tenfold enhancement of the stable photocurrent density over the sol-gel hematite films for both UV and visible irradiation. The superior properties of plasmatic films could be explained by ability to address some of the hematite drawbacks by the deposition of very thin films (25 nm consisting of small densely packed particles and by doping with Sn.

  13. Inexpensive laser-induced surface modification in bismuth thin films

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, A. Reyes [Facultad de Ciencias, Universidad Autónoma del Estado de México, Carretera Toluca, Ixtlahuaca Kilómetro 15.5, C.P. 50200 Edo. de México (Mexico); Hautefeuille, M., E-mail: mathieu_h@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Circuito Exterior S/N, Coyoacán, Ciudad Universitaria, C.P. 04510 D.F. Mexico (Mexico); García, A. Esparza [Fotofísica y Películas Delgadas, Departamento de Tecnociencias, CCADET-UNAM, Circuito exterior s/n C.P. 04510 Cd. Universitaria, D.F. Mexico (Mexico); Mejia, O. Olea [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, Km 14.5, Unidad El Rosedal, 50200 San Cayetano, Estado de México (Mexico); López, M.A. Camacho [Facultad de Química, Universidad Autónoma del Estado de México, Tollocan s/n, esq. Paseo Colón, Toluca, Estado de México 50110 (Mexico)

    2015-05-01

    Highlights: • Laser-induced microbumps were formed on bismuth films using a simple, low-cost, laser setup. • The patterns, similar to those typically obtained with high-power lasers, were characterized. • Control of laser ablation conditions is critical in the fabrication of surface microbumps. - Abstract: In this work, we present results on texturing a 500 nm thick bismuth film, deposited by sputtering onto a glass slide using a low-cost homemade, near-infrared pulsed laser platform. A 785 nm laser diode of a CD–DVD pickup head was precisely focused on the sample mounted on a motorized two-axis translation stage to generate localized surface microbumps on the bismuth films. This simple method successfully transferred desired micropatterns on the films in a computer-numerical control fashion. Irradiated zones were characterized by atomic force microscopy and scanning electron microscopy. It was observed that final results are strongly dependent on irradiation parameters.

  14. Thermally tailored gradient topography surface on elastomeric thin films.

    Science.gov (United States)

    Roy, Sudeshna; Bhandaru, Nandini; Das, Ritopa; Harikrishnan, G; Mukherjee, Rabibrata

    2014-05-14

    We report a simple method for creating a nanopatterned surface with continuous variation in feature height on an elastomeric thin film. The technique is based on imprinting the surface of a film of thermo-curable elastomer (Sylgard 184), which has continuous variation in cross-linking density introduced by means of differential heating. This results in variation of viscoelasticity across the length of the surface and the film exhibits differential partial relaxation after imprinting with a flexible stamp and subjecting it to an externally applied stress for a transient duration. An intrinsic perfect negative replica of the stamp pattern is initially created over the entire film surface as long as the external force remains active. After the external force is withdrawn, there is partial relaxation of the applied stresses, which is manifested as reduction in amplitude of the imprinted features. Due to the spatial viscoelasticity gradient, the extent of stress relaxation induced feature height reduction varies across the length of the film (L), resulting in a surface with a gradient topography with progressively varying feature heights (hF). The steepness of the gradient can be controlled by varying the temperature gradient as well as the duration of precuring of the film prior to imprinting. The method has also been utilized for fabricating wettability gradient surfaces using a high aspect ratio biomimetic stamp. The use of a flexible stamp allows the technique to be extended for creating a gradient topography on nonplanar surfaces as well. We also show that the gradient surfaces with regular structures can be used in combinatorial studies related to pattern directed dewetting.

  15. Dynamic behavior of surface film on LiCoO{sub 2} thin film electrode

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Masaki [Material Engineering Div. 3, Toyota Motor Corporation, 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Department of Applied Chemistry, Graduate School of Urban Environmental Science, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397 (Japan); Dokko, Kaoru; Kanamura, Kiyoshi [Department of Applied Chemistry, Graduate School of Urban Environmental Science, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397 (Japan)

    2008-02-15

    Electrochemical oxidation behavior of non-aqueous electrolytes on LiCoO{sub 2} thin film electrodes were investigated by in situ polarization modulation Fourier transform infrared (PM-FTIR) spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy (XPS). LiCoO{sub 2} thin film electrode on gold substrate was prepared by rf-sputtering method. In situ PM-FTIR spectra were obtained at various electrode potentials during cyclic voltammetry measurement between 3.5 V vs. Li/Li{sup +} and 4.2 V vs. Li/Li{sup +}. During anodic polarization, oxidation of non-aqueous electrolyte was observed, and oxidized products remained on the electrode at the potential higher than 3.75 V vs. Li/Li{sup +} as a surface film. During cathodic polarization, the stripping of the surface film was observed at the potential lower than 3.9 V vs. Li/Li{sup +}. Depth profile of XPS also showed that more organic surface film remained on charged LiCoO{sub 2} than that on discharged one. AFM images of charged and discharged electrodes showed that some decomposed products deposited on charged electrode and disappeared from the surface of discharged one. These results indicate that the surface film on LiCoO{sub 2} is not so stable. (author)

  16. Dynamic behavior of surface film on LiCoO 2 thin film electrode

    Science.gov (United States)

    Matsui, Masaki; Dokko, Kaoru; Kanamura, Kiyoshi

    Electrochemical oxidation behavior of non-aqueous electrolytes on LiCoO 2 thin film electrodes were investigated by in situ polarization modulation Fourier transform infrared (PM-FTIR) spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy (XPS). LiCoO 2 thin film electrode on gold substrate was prepared by rf-sputtering method. In situ PM-FTIR spectra were obtained at various electrode potentials during cyclic voltammetry measurement between 3.5 V vs. Li/Li + and 4.2 V vs. Li/Li +. During anodic polarization, oxidation of non-aqueous electrolyte was observed, and oxidized products remained on the electrode at the potential higher than 3.75 V vs. Li/Li + as a surface film. During cathodic polarization, the stripping of the surface film was observed at the potential lower than 3.9 V vs. Li/Li +. Depth profile of XPS also showed that more organic surface film remained on charged LiCoO 2 than that on discharged one. AFM images of charged and discharged electrodes showed that some decomposed products deposited on charged electrode and disappeared from the surface of discharged one. These results indicate that the surface film on LiCoO 2 is not so stable.

  17. Morphologies and Superhydrophobicity of Hybrid Film Surfaces Based on Silica and Fluoropolymer

    Institute of Scientific and Technical Information of China (English)

    Ailan QU; Xiufang WEN; Pihui PI; Jiang CHENG; Zhuoru YANG

    2008-01-01

    Fluoropolymer and different kinds of silica particles were used for controlling surface chemistry and morphology,respectively. A superhydrophobic surface originated from strawberry-like or quincunx-shaped composite silica particles was obtained. The dual size particles are obtained by utilizing the graft of different modified silica particles with epoxy functional group and amine functional group. This makes the surface of film form a composite interface to have irregular binary structure which plays an essential role in trapping air between the substrate surface and the liquid droplets to be necessary for high contact angle and low contact anglehysteresis. The maximum contact angle for water on the hybrid film is about 174±2° and the contact angle hysteresis is less than 2°. The surface morphologies, roughness and the wettability on the surface of films containing different structural silica particles were compared. It was shown that the hierarchical irregularly structure with a low roughness factor and high air-trapped ratio is indispensable for superhydrophobic surface.Although this structural surfaces based on composite silica particles play a vital role in governing the surface wettability, it is necessary to combine with a low surface energy to make the surface superhydrophobic.

  18. Magnetic Surfaces, Thin Films, and Multilayers

    Science.gov (United States)

    1992-01-01

    PERPENDICULAR MAGNETIC ANISOTROPY AND MAGNETO-OPTICS * PERPENDICULAR MAGNETIC ANISOTROPY OF Pd/Co AND RELATED MULTILAYERS 441 S...THE PERPENDICULAR MAGNETIC ANISOTROPY AND STRUCTURE OF SPUTTERED Ag/Co, Pd/Co, AND AgPd/Co MULTILAYERED FILMS 473 Akira Yamaguchi, We-Hyo Soe, Ryoichi...the magnetic phase transi- tion and magnetic anisotropy, has attracted considerable interest. Theoretical predictions on perpendicular magnetic anisotropy

  19. Remote Sensing: Environmental Effects of Surface Films.

    Science.gov (United States)

    1992-12-15

    constitution of natural film-forming material. " Protein: heptone from soybeans, C/N approx. 6 " Carbohydrates: alginic acid, MW-240,00 (polymannuronic...acid) " Lipid: triolein, MW=885.4 Mlix peptone (25% as carbon), alginic acid (50% as carbon), and triolein (25% as carbon). It should be restated that...and the rheology Initial experiments were performed in the laboratory and )f the air-sea interface. It will be shown in ensuing sections on the

  20. Water-Soluble Multi-Walled Nanotube and its Film Characteristics

    Institute of Scientific and Technical Information of China (English)

    FENG Wei(郭镇); ZHOU Feng(红); WANG Xiao-Gong(叶瑜黄); WAN Mei-Xiang(星景志); FUJII Akihiko(圣锦); YOSHINO Katsumi(江冰林)

    2003-01-01

    Covalent modification of multi-walled-nanotube (MWNT) surface-enhanced solubility in water yields a thin transparent shining dark-coloured film of soluble MWNT (s-MWNT) with a conductivity of 1.25S/cm. Fourier transform infrared spectroscopy, scanning electron microscopy, transmission-electron microscopy, and UV-vis absorption spectroscopy were used for thefilm characterization. The result shows that enhanced interactions between s-MWNT and water and between s-MWNTs play an important role in increasing the solubility of the nanotubes in water and in the formation of uniform thin films.

  1. Study on sodium water glass-based anti-reflective film and its application in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Q.Z. [Key Laboratory of Renewable Energy, Guangdong Key Laboratory of New and Renewable Energy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shi, J.F., E-mail: shijf@ms.giec.ac.cn [Key Laboratory of Renewable Energy, Guangdong Key Laboratory of New and Renewable Energy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510000 (China); Wang, L.L.; Li, Y.J.; Zhong, L.W. [Key Laboratory of Renewable Energy, Guangdong Key Laboratory of New and Renewable Energy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510000 (China); Xu, G., E-mail: xugang@ms.giec.ac.cn [Key Laboratory of Renewable Energy, Guangdong Key Laboratory of New and Renewable Energy Research and Development, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510000 (China)

    2016-07-01

    In this paper, anti-reflective (AR) films are prepared from sodium water glass with a simple dip-coating method. The effects of SiO{sub 2}/Na{sub 2}O molar ratio, concentration of water glass, and withdrawal speed on the anti-reflection performance of the AR films are systematically studied. The optimized AR film is further applied in dye-sensitized solar cells (DSCs). The optical properties and surface morphology of AR films are analyzed by ultraviolet-visible spectrophotometer, scanning electron microscope, and atomic force microscope. Transmittance of the glass coated with sodium water glass-based AR film is increased by 3.2% when the SiO{sub 2}/Na{sub 2}O molar ratio, concentration, and withdrawal speed equal to 3.8, 5 wt%, and 80 mm/min, respectively. Under this condition, the thickness of the AR film is 127 nm and the AR film has obvious porous structure. In addition, the power conversion efficiency of DSC coated by AR film is increased from 7.92% to 8.24%, compared with the DSC without AR film. - Highlights: • Anti-reflective films are prepared from sodium water glass. • Transmittance of anti-reflective film is increased by 3.2%. • Efficiency of dye-sensitized cell is improved by anti-reflective film.

  2. RUPTURING OF POLYMER FILMS WITH RUBBING—INDUCED SURFACE DEFECTS

    Institute of Scientific and Technical Information of China (English)

    B.Du; F.C.Xie; Y.J.Wang; O.K.C.Tsui; O.K.C.Tsui

    2003-01-01

    It has been a long-standing question whether dewetting of polymer film from non-wettable substrate surfaces wherein the bicontinuous morphology never forms in the dewetting film is due to spinodal instability or heterogeneous nucleation.In this experiment,we use a simple method to make the distinction through introduction of topographical defects of the films by rubbing the sample surface with a rayon cloth.Spinodal dewetting is identified for those films that dewet by a characteristic wavevector,q,independent of the density of rubbing-induced defects.Heterogeneous nucleation,on the other hand,is identified for those with q increasing with increasing density of defects.Our result shows that PS films on oxide coated silicon with thickness less than≈13nm are dominated by spinodal dewetting,but the thicker films are dominated by nucleation dewetting.We also confirm that spinodal dewetting does not necessarily lead to a bicontinuous morphology in the dewetting film,contrary to the classic theory of Cahn.

  3. Surface acoustic wave devices including Langmuir-Blodgett films (Review)

    Science.gov (United States)

    Plesskii, V. P.

    1991-06-01

    Recent theoretical and experimental research related to the use of Langmuir-Blodgett (LB) films in surface acoustic wave (SAW) devices is reviewed. The sensitivity of the different cuts of quartz and lithium niobate to inertial loading is investigated, and it is shown that some cuts in lithium niobate are twice as sensitive to mass loading than the commonly used YZ-cut. The large variety of organic compounds suitable for the production of LB films makes it possible to create SAW sensors reacting selectively to certain substances. The existing SAW sensors based on LB films are characterized by high sensitivity and fast response.

  4. Sliding behavior of water drops on sol-gel derived hydrophobic silica films

    Energy Technology Data Exchange (ETDEWEB)

    Latthe, Sanjay S.; Dhere, Sunetra L. [Air Glass Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, Maharashtra (India); Kappenstein, Charles [University of Poitiers, Laboratory of Catalysis in Organic Chemistry, LA CCO, UMR CNRS 6503, Poitiers-86000 (France); Imai, Hiroaki [Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Ganesan, V. [CSR, Indore Centre, University Campus, Khandwa Road, Indore- 452 017, Madhyapradesh (India); Rao, A. Venkateswara, E-mail: avrao2012@gmail.com [Air Glass Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, Maharashtra (India); Wagh, Pratap B.; Gupta, Satish C. [Applied Physics Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai 400 085 (India)

    2010-03-01

    Control on the wettability of solid state materials is a classical and key issue in surface engineering. Optically transparent methyltriethoxysilane (MTES)-based silica films with water sliding angle as low as 9{sup o} were successfully prepared by two-step sol-gel co-precursor method. The emphasis is given to the effect of trimethylethoxysilane (TMES) as a co-precursor on water sliding behavior of silica films. The coating sol was prepared with molar ratio of methyltriethoxysilane (MTES), methanol (MeOH), acidic water (0.01 M, oxalic acid) and basic water (12 M, NH{sub 4}OH) kept constant at 1:12.73:3.58:3.58 respectively, and the molar ratio of TMES/MTES (M) was varied from 0 to 0.22. The static water contact angle as high as 120{sup o} and the water sliding angle as low as 9{sup o} was obtained by keeping the molar ratio (M) of TMES/MTES at 0.22. When the modified films were cured at temperature higher than 280 deg. C, the films became superhydrophilic. Further, the humidity study was carried out at a relative humidity of 90% at 30 deg. C over 60 days. We characterized the water repellent silica films by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), % of optical transmission, humidity tests and static and dynamic water contact angle (CA) measurements.

  5. Fabrication and Surface Properties of Composite Films of SAM/Pt/ZnO/SiO 2

    KAUST Repository

    Yao, Ke Xin

    2008-12-16

    Through synthetic architecture and functionalization with self-assembled monolayers (SAMs), complex nanocomposite films of SAM/Pt/ZnO/SiO2 have been facilely prepared in this work. The nanostructured films are highly uniform and porous, showing a wide range of tunable wettabilities from superhydrophilicity to superhydrophobicity (water contact angles: 0° to 170°). Our approach offers synthetic flexibility in controlling film architecture, surface topography, coating texture, crystallite size, and chemical composition of modifiers (e.g., SAMs derived from alkanethiols). For example, wettability properties of the nanocomposite films can be finely tuned with both inorganic phase (i.e., ZnO/SiO2 and Pt/ZnO/SiO2) and organic phase (i.e., SAMs on Pt/ZnO/SiO2). Due to the presence of catalytic components Pt/ZnO within the nanocomposites, surface reactions of the organic modifiers can further take place at room temperature and elevated temperatures, which provides a means for SAM formation and elimination. Because the Pt/ZnO forms an excellent pair of metal-semiconductors for photocatalysis, the anchored SAMs can also be modified or depleted by UV irradiation (i.e., the films possess self-cleaning ability). Potential applications of these nanocomposite films have been addressed. Our durability tests also confirm that the films are thermally stable and structurally robust in modification- regeneration cycles. © 2008 American Chemical Society.

  6. Environmental stability of solution processed Al-doped ZnO naoparticulate thin films using surface modification technique

    Energy Technology Data Exchange (ETDEWEB)

    Vunnam, Swathi, E-mail: swathivunnam@gmail.com [Program of Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States); Ankireddy, Krishnamraju; Kellar, Jon [Program of Materials Engineering and Science, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States); Cross, William, E-mail: William.Cross@sdsmt.edu [Program of Materials Engineering and Science, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States)

    2014-12-15

    Graphical abstract: - Highlights: • AZO nanoparticulate films were deposited using ultrasonic spray deposition. • Functionalization of solution processed AZO thin films was carried out. • Contact angles and QNM AFM results confirmed the existence of molecular layers. • Environmental stability of AZO films greatly increased with surface modification. - Abstract: The environmental stability of solution processed Al-doped ZnO (AZO) thin films was enhanced by functionalizing the film surface with a thin self-assembled molecular layer. Functionalization of AZO films was performed using two types of molecules having identical 12-carbon alkyl chain termination but different functional groups: dodecanethiol (DDT) and dodecanoic acid (DDA). Surface modified AZO films were examined using electrical resistivity measurements, contact angle measurements and quantitative nanomechanical property mapping atomic force microscopy. The hydrophobic layer inhibits the penetration of oxygen and water into the AZO's grain boundaries thus significantly increasing the environmental stability over unmodified AZO. Surface modified AZO films using DDT exhibited lower electrical resistivity compared to DDA functionalized AZO films. Our study demonstrates a new approach for improving the physical properties of oxide based nanoparticulate films for device applications.

  7. Water surface capturing by image processing

    Science.gov (United States)

    An alternative means of measuring the water surface interface during laboratory experiments is processing a series of sequentially captured images. Image processing can provide a continuous, non-intrusive record of the water surface profile whose accuracy is not dependent on water depth. More trad...

  8. Cross-Linking Poly(lactic acid) Film Surface by Neutral Hyperthermal Hydrogen Molecule Bombardment.

    Science.gov (United States)

    Du, Wangli; Shao, Hong; He, Zhoukun; Tang, Changyu; Liu, Yu; Shen, Tao; Zhu, Yan; Lau, Woon-ming; Hui, David

    2015-12-16

    Constructing a dense cross-linking layer on a polymer film surface is a good way to improve the water resistance of poly(lactic acid) (PLA). However, conventional plasma treatments have failed to achieve the aim as a result of the unavoidable surface damage arising from the charged species caused by the uncontrolled high energy coming from colliding ions and electrons. In this work, we report a modified plasma method called hyperthermal hydrogen-induced cross-linking (HHIC) technology to construct a dense cross-linking layer on PLA film surfaces. This method produces energy-controlled neutral hyperthermal hydrogen, which selectively cleaves C-H bonds by molecule collision from the PLA film without breaking other bonds (e.g., C-C bonds in the polymer backbone), and results in subsequent cross-linking of the carbon radicals generated from the organic molecules. The formation of a dense cross-linking layer can serve as a barrier layer to significantly improve both the hydrophobicity and water vapor barrier property of the PLA film. Because of the advantage of selective cleavage of C-H bonds by HHIC treatment, the original physical properties (e.g., mechanical strength and light transmittance) of the PLA films are well-preserved.

  9. Demonstration of a plasma mirror based on a laminar flow water film

    Energy Technology Data Exchange (ETDEWEB)

    Panasenko, Dmitriy; Shu, Anthony; Gonsalves, Anthony; Nakamura, Kei; Matlis, Nicholas; Toth, Csaba; Leemans, Wim

    2011-07-22

    A plasma mirror based on a laminar water film with low flow speed 0.5-2 cm/s has been developed and characterized, for use as an ultrahigh intensity optical reflector. The use of flowing water as atarget surface automatically results in each laser pulse seeing a new interaction surface and avoids the need for mechanical scanning of the target surface. In addition, the breakdown of water does notproduce contaminating debris that can be deleterious to vacuum chamber conditions and optics, such as is the case when using conventional solid targets. The mirror exhibits 70percent reflectivity, whilemaintaining high-quality of the reflected spot.

  10. Unidirectional propagation of magnetostatic surface spin waves at a magnetic film surface

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Kin L.; Bao, Mingqiang, E-mail: mingqiangbao@gmail.com, E-mail: caross@mit.edu; Lin, Yen-Ting; Wang, Kang L. [Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, California 90095 (United States); Bi, Lei [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Wen, Qiye; Zhang, Huaiwu [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Chatelon, Jean Pierre [Univerisité de Saint-Etienne, Université de Lyon, LT2C, 25 rue du Docteur Rémy Annino, 42000 Saint-Etienne (France); Ross, C. A., E-mail: mingqiangbao@gmail.com, E-mail: caross@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-12-08

    An analytical expression for the amplitudes of magnetostatic surface spin waves (MSSWs) propagating in opposite directions at a magnetic film surface is presented. This shows that for a given magnetic field H, it is forbidden for an independent MSSW to propagate along the direction of −H{sup →}×n{sup →}, where n{sup →} is the surface normal. This unidirectional propagation property is confirmed by experiments with both permalloy and yttrium iron garnet films of different film thicknesses, and has implications in the design of spin-wave devices such as isolators and spin-wave diodes.

  11. In situ speciation of dissolved inorganic antimony in surface waters and sediment porewaters: development of a thiol-based diffusive gradients in thin films technique for Sb(III).

    Science.gov (United States)

    Bennett, William W; Arsic, Maja; Welsh, David T; Teasdale, Peter R

    2016-08-10

    Antimony is a priority environmental contaminant typically present as either the trivalent (Sb(III)) or the pentavalent (Sb(V)) oxidation state in aquatic systems. Both the toxicity and mobility of antimony are affected by its speciation, and thus the accurate measurement of antimony speciation is essential for investigating the behaviour of this contaminant in aquatic systems. Here we present a diffusive gradients in thin films (DGT) technique, which utilises a binding layer containing a thiol-based adsorbent (3-mercaptopropyl functionalised silica gel), for the selective measurement of Sb(III) in surface waters and sediment porewaters. We also evaluated the Metsorb DGT technique, which has been previously reported to accurately measure Sb(V), for its ability to accumulate Sb(III) and thus allow the measurement of total inorganic antimony. Both the mercapto-silica and Metsorb DGT techniques showed a high affinity for Sb(III), with uptake efficiencies >97%. Elution efficiencies of 86.9 ± 2.6% and 88.1 ± 1.2% were obtained for mercapto-silica and Metsorb, respectively, with 1 mol L(-1) H2O2 in 1 mol L(-1) NaOH. The accumulation of Sb(III) by these DGT techniques was linear with time (R(2) > 0.99) and unaffected by pH (4.07-8.05), ionic strength (0.001-1.0 mol L(-1) NaCl), bicarbonate (1-15 mmol L(-1)), and an artificial seawater matrix (pH 8.34; salinity 34.8). Finally, the mercapto-silica DGT technique was applied to measure porewater concentrations of Sb(III) and As(III) in a contaminated freshwater sediment at high resolution.

  12. Weak non-linear surface charging effects in electrolytic films

    OpenAIRE

    Dean, D. S.; Horgan, R. R.

    2002-01-01

    A simple model of soap films with nonionic surfactants stabilized by added electrolyte is studied. The model exhibits charge regularization due to the incorporation of a physical mechanism responsible for the formation of a surface charge. We use a Gaussian field theory in the film but the full non-linear surface terms which are then treated at a one-loop level by calculating the mean-field Poisson-Boltzmann solution and then the fluctuations about this solution. We carefully analyze the reno...

  13. Metal-Organic Framework Thin Films as Platforms for Atomic Layer Deposition of Cobalt Ions To Enable Electrocatalytic Water Oxidation.

    Science.gov (United States)

    Kung, Chung-Wei; Mondloch, Joseph E; Wang, Timothy C; Bury, Wojciech; Hoffeditz, William; Klahr, Benjamin M; Klet, Rachel C; Pellin, Michael J; Farha, Omar K; Hupp, Joseph T

    2015-12-30

    Thin films of the metal-organic framework (MOF) NU-1000 were grown on conducting glass substrates. The films uniformly cover the conducting glass substrates and are composed of free-standing sub-micrometer rods. Subsequently, atomic layer deposition (ALD) was utilized to deposit Co(2+) ions throughout the entire MOF film via self-limiting surface-mediated reaction chemistry. The Co ions bind at aqua and hydroxo sites lining the channels of NU-1000, resulting in three-dimensional arrays of separated Co ions in the MOF thin film. The Co-modified MOF thin films demonstrate promising electrocatalytic activity for water oxidation.

  14. Photochemical Charge Separation in Nanocrystal Photocatalyst Films: Insights from Surface Photovoltage Spectroscopy.

    Science.gov (United States)

    Zhao, Jing; Osterloh, Frank E

    2014-03-01

    Photochemical charge generation, separation, and transport at nanocrystal interfaces are central to photoelectrochemical water splitting, a pathway to hydrogen from solar energy. Here, we use surface photovoltage spectroscopy to probe these processes in nanocrystal films of HCa2Nb3O10, a proven photocatalyst. Charge injection from the nanoparticles into the gold support can be observed, as well as oxidation and reduction of methanol and oxygen adsorbates on the nanosheet films. The measured photovoltage depends on the illumination intensity and substrate material, and it varies with illumination time and with film thickness. The proposed model predicts that the photovoltage is limited by the built-in potential of the nanosheet-metal junction, that is, the difference of Fermi energies in the two materials. The ability to measure and understand these light-induced charge separation processes in easy-to-fabricate films will promote the development of nanocrystal applications in photoelectrochemical cells, photovoltaics, and photocatalysts.

  15. Surface modification by plasma polymerization: film deposition, tailoring of surface properties and biocompatibility

    NARCIS (Netherlands)

    Os, van Menno Thomas

    2000-01-01

    The work described in this thesis concerns the surface modification of materials by thin film deposition in a plasma reactor. In particular, thin polymeric films bearing amine functionalities were synthesized by plasma polymerization of amino group containing monomers. In addition to the synthesis,

  16. Surface characterization and AFM imaging of mixed fibrinogen-surfactant films.

    Science.gov (United States)

    Hassan, Natalia; Maldonado-Valderrama, Julia; Gunning, A Patrick; Morris, Victor J; Ruso, Juan M

    2011-05-19

    This study describes the adsorption behavior of mixed protein/surfactant systems at the air-water interface: specifically fibrinogen and the fluorinated and hydrogenated surfactants (C(8)FONa, C(8)HONa, and C(12)HONa). Surface tension techniques and atomic force microscopy (AFM) have been combined to investigate the adsorption behavior of these mixed systems. Interfacial rheology showed that fibrinogen has a low dilatational modulus at the air-water interface when compared to other proteins, suggesting the formation of a weak surface network. Fluorinated and hydrogenated surfactants severely decreased the dilatational modulus of the adsorbed fibrinogen film at the air-water interface. These measurements suggest the progressive displacement of fibrinogen from the air-water interface by both types of surfactants. However, in the case of fibrinogen/fluorinated surfactant systems, surface tension and dilatational rheology measurements suggest the formation of complexes with improved surface activity. AFM imaging of fibrinogen in the presence and absence of surfactants provided new information on the structure of mixed surface films, and revealed new features of the interaction of fibrinogen with hydrogenated and fluorinated surfactants. These studies suggest complexes formed between fibrinogen and fluorinated surfactants which are more surface active than fibrinogen, while the absence of interaction between fibrinogen and hydrogenated surfactants (C(8)HONa and C(12)HONa) results in compaction of the surface layer.

  17. Quantum Transport and Surface Scattering in Magnetic Metallic Film

    Institute of Scientific and Technical Information of China (English)

    HU Yin; DONG Zheng-Chao

    2008-01-01

    Taking into account the quantum size effect and the spin dependence of the electronic band structure,and including the spin dependence of the scattering from bulk impurities and two different sets of surface roughness,we present a theory on the electronic transport in magnetic film,in which the average autocorrelation function (ACF) for surface roughness is described by a Gaussion model.Our result shows that the conductivity is a sensitive function of surface roughness and exchange energy.It is also found that in the thin film limit and in the lower-order approximation of the surface scattering,the total conductivity is given by a sum of conductivities of all the subbands and the two spin channels,for each subband and each spin channel the scattering rates due to the impurities and two surfaces are additive.

  18. Particle Size Controls on Water Adsorption and Condensation Regimes at Mineral Surfaces

    OpenAIRE

    Merve Yeşilbaş; Jean-François Boily

    2016-01-01

    Atmospheric water vapour interacting with hydrophilic mineral surfaces can produce water films of various thicknesses and structures. In this work we show that mineral particle size controls water loadings achieved by water vapour deposition on 21 contrasting mineral samples exposed to atmospheres of up to ~16 Torr water (70% relative humidity at 25 °C). Submicrometer-sized particles hosted up to ~5 monolayers of water, while micrometer-sized particles up to several thousand monolayers. All f...

  19. Surface Properties of Squalene/Meibum Films and NMR Confirmation of Squalene in Tears

    Directory of Open Access Journals (Sweden)

    Slavyana Ivanova

    2015-09-01

    Full Text Available Squalene (SQ possesses a wide range of pharmacological activities (antioxidant, drug carrier, detoxifier, hydrating, emollient that can be of benefit to the ocular surface. It can come in contact with human meibum (hMGS; the most abundant component of the tear film lipid layer as an endogenous tear lipid or from exogenous sources as eyelid sebum or pharmaceuticals. The aims of this study were to determine (i if SQ is in tear lipids and (ii its influence on the surface properties of hMGS films. Heteronuclear single quantum correlation NMR confirmed 7 mol % SQ in Schirmer’s strips extracts. The properties of SQ/hMGS pseudo-binary films at the air/water interface were studied with Langmuir surface balance, stress-relaxation dilatational rheology and Brewster angle microscopy. SQ does not possess surfactant properties. When mixed with hMGS squalene (i localized over the layers’ thinner regions and (ii did not affect the film pressure at high compression. Therefore, tear SQ is unlikely to instigate dry eye, and SQ can be used as a safe and “inert” ingredient in formulations to protect against dry eye. The layering of SQ over the thinner film regions in addition to its pharmacological properties could contribute to the protection of the ocular surface.

  20. Surface energy characteristics of zeolite embedded PVDF nanofiber films with electrospinning process

    Science.gov (United States)

    Kang, Dong Hee; Kang, Hyun Wook

    2016-11-01

    Electrospinning is a nano-scale fiber production method with various polymer materials. This technique allows simple fiber diameters control by changing the physical conditions such as applied voltage and polymer solution viscosity during the fabrication process. The electrospun polymer fibers form a thin porous film with high surface area to volume ratio. Due to these unique characteristics, it is widely used for many application fields such as photocatalyst, electric sensor, and antibacterial scaffold for tissue engineering. Filtration is one of the main applications of electrospun polymer fibers for specific application of filtering out dust particles and dehumidification. Most polymers which are commonly used in electrospinning are hard to perform the filtering and dehumidification simultaneously because of their low hygroscopic property. To overcome this obstacle, the desiccant polymers are developed such as polyacrylic acid and polysulfobetaine methacrylate. However, the desiccant polymers are generally expensive and need special solvent for electrospinning. An alternating way to solve these problems is mixing desiccant material like zeolite in polymer solution during an electrospinning process. In this study, the free surface energy characteristics of electrospun polyvinylidene fluoride (PVDF) film with various zeolite concentrations are investigated to control the hygroscopic property of general polymers. Fundamental physical property of wettability with PVDF shows hydrophobicity. The electrospun PVDF film with small weight ratio with higher than 0.1% of zeolite powder shows diminished contact angles that certifying the wettability of PVDF can be controlled using desiccant material in electrospinning process. To quantify the surface energy of electrospun PVDF films, sessile water droplets are introduced on the electrospun PVDF film surface and the contact angles are measured. The contact angles of PVDF film are 140° for without zeolite and 80° for with 5

  1. Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

    Science.gov (United States)

    Reis, Rackel; Dumée, Ludovic F.; Tardy, Blaise L.; Dagastine, Raymond; Orbell, John D.; Schutz, Jürg A.; Duke, Mikel C.

    2016-07-01

    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties.

  2. Microstructure and Magnetic Domains of Iron Films on Liquid Surfaces

    Institute of Scientific and Technical Information of China (English)

    XIE Jian-Ping; XIA A-Gen; ZHANG Chu-Hang; YANG Bo; FANG Zheng-Nong; YE Gao-Xiang

    2009-01-01

    Iron (Fe) films with a thickness ranging from 1.0 nm to 80.0 nm are deposited on silicone oil surfaces by a vapor phase deposition method. The films with a thickness of d < 2.0 nm do not exhibit planar morphology but ramified aggregates instead. Magnetic force microscopy studies for the Fe films (10.0nm≤d≤80.0nm) show that the domain wall structure is widespread and irregularly shaped and the oscillation phase shift Δθ, which records as the magnetic force image, changes from 0.29°to 0.81°. Correspondingly, the magnetic force gradient varies from 1.4×10~(-3) to 4.0×10~(-3)N/m, respectively. In our measurement, the characteristic domain walls, such as Bloch walls, Neel walls and cross-tie walls, are not observed in the film system clearly.

  3. Photoelectrochemical water splitting on nanoporous GaN thin films for energy conversion under visible light

    Science.gov (United States)

    Cao, Dezhong; Xiao, Hongdi; Fang, Jiacheng; Liu, Jianqiang; Gao, Qingxue; Liu, Xiangdong; Ma, Jin

    2017-01-01

    Nanoporous (NP) GaN thin films, which were fabricated by an electrochemical etching method at different voltages, were used as photoelectrodes during photoelectrochemical (PEC) water splitting in 1 M oxalic acid solution. Upon illumination at a power density of 100 mW cm‑2 (AM 1.5), water splitting is observed in NP GaN thin films, presumably resulting from the valence band edge which is more positive than the redox potential of the oxidizing species. In comparison with NP GaN film fabricated at 8 V, NP GaN obtained at 18 V shows nearly twofold enhancement in photocurrent with the maximum photo-to-hydrogen conversion efficiency of 1.05% at ~0 V (versus Ag/AgCl). This enhancement could be explained with (i) the increase of surface area and surface states, and (ii) the decrease of resistances and carrier concentration in the NP GaN thin films. High stability of the NP GaN thin films during the PEC water splitting further confirms that the NP GaN thin film could be applied to the design of efficient solar cells and solar fuel devices.

  4. Surface chemistry and spectroscopy of UG8 asphaltene Langmuir film, part 1.

    Science.gov (United States)

    Orbulescu, Jhony; Mullins, Oliver C; Leblanc, Roger M

    2010-10-05

    This research focuses on a systematic investigation of UG8 asphaltene Langmuir films at the air-water interface using toluene as the spreading solvent. From the surface pressure-area isotherms, it was concluded that small-sized aggregates are spread on the water surface and the compression of the film leads to formation of large aggregates. Our methods provide a stringent test and confirmation for the formation of corresponding asphaltene nanoaggregates that have recently been proposed for bulk solutions. These results were confirmed by compression-decompression isotherms, Brewster angle microscopy, and p-polarized infrared reflection-absorption spectroscopy. The transfer of a single layer using both the Langmuir-Schaefer and Langmuir-Blodgett deposition techniques shows different aggregate shapes depending on the technique used as imaged using atomic force microscopy. The films reveal the existence of nanoaggregates spread on the water surface that coexist with large aggregates formed during compression. For the nanoaggregate, the thickness of the Langmuir-Schaefer and Langmuir-Blodgett films determined by AFM is consistent with small aggregation numbers of nanoaggregates determined by Langmuir film compression. In addition to these findings, the spreading solvent, toluene, was found to be trapped within the aggregates as confirmed by in situ UV-vis spectroscopy at the air-water interface. This result was possible only after waiting a time period of 1 h to allow the complete evaporation of the spreading solvent. This is the only study that reveals the presence of the in situ toluene within the UG8 aggregates directly at the air-water interface.

  5. Safe Drinking Water Information System (SDWIS) Surface Water Intakes

    Data.gov (United States)

    U.S. Environmental Protection Agency — This is a point feature dataset showing the locations of surface water intakes. These intake locations are part of the safe drinking water information system...

  6. Gas Absorption by Wavy Falling Liquid Film Formed on Inner Surface of Vertical Tubes

    Institute of Scientific and Technical Information of China (English)

    Akio Miyara; Tomoki Yamamoto; Toru Iemura; Takashi Shimada

    2003-01-01

    An experimental study on gas absorption into falling liquid film formed on inner surface of vertical tubes has been carried out in order to clarify fundamental characteristics of the gas absorption and enhancement by surface waves. The water supplied into the test tubes is periodically disturbed by fluctuating a silicon tube before the test section with a speaker and the wavy films absorb the oxygen filled in the tubes. Imposing the periodic disturbance enhances the gas absorption and the enhancement has a maximum at around 20~30 Hz, where the gas absorption is 20~30% higher. Mass transfer coefficients obtained with five tubes agree well with those obtained with single tube. Two-dimensional numerical simulations have also been conducted for gas absorption by wavy film and the enhancement mechanism of the gas absorption is discussed.

  7. Surface and interface properties of industrially relevant polymers Thin polymer films

    CERN Document Server

    Maccarini, M

    2002-01-01

    This thesis is concerned with the study of some important properties of thin polymer films focusing on two main aspects: the morphologies induced on spin coated polymer films, and swelling and absorption phenomena. Chapter 2 provides an introduction on the theoretical aspects relevant in the field of Polymer Physics: the mixing properties of polymers and solvent, the glass transition temperature, diffusion, surface effects and surface tension, and spin coating. Chapter 3 focuses on the experimental techniques used in this work: Ellipsometry, Quartz Crystal Microbalance, Optical Microscopy and Differential Scanning Calorimetry. Moreover, a description of the material studied is provided. In Chapter 4 a first characterisation of the system investigated is carried out: water absorption and glass transition temperature are measured for bulk material in different moist condition. The refracting indices and the densities of the polymer films are experimentally determined. In Chapter 5 we describe a systematic inves...

  8. Water-insoluble Silk Films with Silk I Structure

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Q.; Hu, X; Wang, X; Kluge, J; Lu, S; Cebe, P; Kaplan, D

    2010-01-01

    Water-insoluble regenerated silk materials are normally produced by increasing the {beta}-sheet content (silk II). In the present study water-insoluble silk films were prepared by controlling the very slow drying of Bombyx mori silk solutions, resulting in the formation of stable films with a predominant silk I instead of silk II structure. Wide angle X-ray scattering indicated that the silk films stabilized by slow drying were mainly composed of silk I rather than silk II, while water- and methanol-annealed silk films had a higher silk II content. The silk films prepared by slow drying had a globule-like structure at the core surrounded by nano-filaments. The core region was composed of silk I and silk II, surrounded by hydrophilic nano-filaments containing random turns and {alpha}-helix secondary structures. The insoluble silk films prepared by slow drying had unique thermal, mechanical and degradative properties. Differential scanning calorimetry results revealed that silk I crystals had stable thermal properties up to 250 C, without crystallization above the T{sub g}, but degraded at lower temperatures than silk II structure. Compared with water- and methanol-annealed films the films prepared by slow drying had better mechanical ductility and were more rapidly enzymatically degraded, reflecting the differences in secondary structure achieved via differences in post processing of the cast silk films. Importantly, the silk I structure, a key intermediate secondary structure for the formation of mechanically robust natural silk fibers, was successfully generated by the present approach of very slow drying, mimicking the natural process. The results also point to a new mode of generating new types of silk biomaterials with enhanced mechanical properties and increased degradation rates, while maintaining water insolubility, along with a low {beta}-sheet content.

  9. A comparison of surface properties of metallic thin film photocathodes

    CERN Document Server

    Mistry, Sonal; Valizadeh, Reza; Jones, L.B; Middleman, Keith; Hannah, Adrian; Militsyn, B.L; Noakes, Tim

    2017-01-01

    In this work the preparation of metal photocathodes by physical vapour deposition magnetron sputtering has been employed to deposit metallic thin films onto Cu, Mo and Si substrates. The use of metallic cathodes offers several advantages: (i) metal photocathodes present a fast response time and a relative insensitivity to the vacuum environment (ii) metallic thin films when prepared and transferred in vacuum can offer smoother and cleaner emitting surfaces. The photocathodes developed here will ultimately be used in S-band Normal Conducting RF (NCRF) guns such as that used in VELA (Versatile Electron Linear Accelerator) and the proposed CLARA (Compact Linear Accelerator for Research and Applications) Free Electron Laser test facility. The samples grown on Si substrates were used to investigate the morphology and thickness of the film. The samples grown onto Cu and Mo substrates were analysed and tested as photocathodes in a surface characterisation chamber, where X-Ray Photoelectron spectroscopy (XPS) was em...

  10. Surface conductivity measurements in nanometric to micrometric foam films.

    Science.gov (United States)

    Bonhomme, Oriane; Mounier, Anne; Simon, Gilles; Biance, Anne-Laure

    2015-05-20

    Foam films (a liquid lamella in air covered by surfactants) are tools of choice for nanofluidic characterization as they are intrinsically nanometric. Their size is indeed fixed by a balance between external pressure and particular molecular interactions in the vicinity of interfaces. To probe the exact nature of these interfaces, different characterizations can be performed. Among them, conductivity in confined systems is a direct probe of the electrostatic environment in the vicinity of the surface. Therefore, we designed a dedicated experiment to measure this conductivity in a cylindrical bubble coupled to interferometry for film thickness characterization. We then show that this conductivity depends on the surfactant nature. These conductivity measurements have been performed in an extremely confined system, the so called Newton black foam films. Unexpectedly in this case, a conductivity close to surface conductivity is recovered.

  11. Anti-Aliased Rendering of Water Surface

    Institute of Scientific and Technical Information of China (English)

    Xue-Ying Qin; Eihachiro Nakamae; Wei Hua; Yasuo Nagai; Qun-Sheng Peng

    2004-01-01

    Water surface is one of the most important components of landscape scenes. When rendering spacious far from the viewpoint. This is because water surface consists of stochastic water waves which are usually modeled by periodic bump mapping. The incident rays on the water surface are actually scattered by the bumped waves,pattern, we estimate this solid angle of reflected rays and trace these rays. An image-based accelerating method is adopted so that the contribution of each reflected ray can be quickly obtained without elaborate intersection calculation. We also demonstrate anti-aliased shadows of sunlight and skylight on the water surface. Both the rendered images and animations show excellent effects on the water surface of a reservoir.

  12. Structural properties and surface wettability of Cu-containing diamond-like carbon films prepared by a hybrid linear ion beam deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Peng; Sun, Lili; Li, Xiaowei [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Xu, Sheng [Gao Hong Coating Technology Co., Ltd, Huzhou 313000 (China); Ke, Peiling [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang, Aiying, E-mail: aywang@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-06-01

    Cu-containing diamond-like carbon (Cu-DLC) films were deposited on Si/glass substrate by a hybrid ion beam deposition system. The Cu concentration (0.1–39.7 at.%) in the film was controlled by varying the sputtering current. The microstructure and composition of Cu-DLC films were investigated systematically. The surface topography, roughness and surface wettability of the films were also studied. Results indicated that with increasing the Cu concentration, the water contact angle of the films changed from 66.8° for pure carbon film to more than 104.4° for Cu-DLC films with Cu concentration larger than 24.4 at.%. In the hydrophilic region, the polar surface energy decreased from 30.54 mJ/m{sup 2} for pure carbon film to 2.48 mJ/m{sup 2} for the film with Cu 7.0 at.%. - Highlights: • Cu-containing diamond-like carbon (DLC) films were deposited by a hybrid ion beam system. • Cu-containing DLC films exhibited a wide range of water contact angle. • The water contact angles vary with the surface energies and surface roughness.

  13. Surface properties and exponential stress relaxations of mammalian meibum films.

    Science.gov (United States)

    Eftimov, Petar; Yokoi, Norihiko; Tonchev, Vesselin; Nencheva, Yana; Georgiev, Georgi As

    2017-03-01

    The surface properties of meibomian secretion (MGS), the major constituent of the tear film (TF) lipid layer, are of key importance for TF stability. The interfacial properties of canine, cMGS, and feline, fMGS, meibum films were studied using a Langmuir surface balance. These species were selected because they have blinking frequency and TF stability similar to those of humans. The sample's performance during dynamic area changes was evaluated by surface pressure (π)-area (A) isocycles and the layer structure was monitored with Brewster angle microscopy. The films' dilatational rheology was probed via the stress-relaxation technique. The animal MGS showed similar behavior both between each other and with human MGS (studied previously). They form reversible, non-collapsible, multilayer thick films. The relaxations of canine, feline, and human MGS films were well described by double exponential decay reflecting the presence of two processes: (1) fast elastic process, with characteristic time τ  100 s-emphasizing the meibum layers viscoelasticity. The temperature decrease from 35 to 25 °C resulted in decreased thickness and lateral expansion of all MGS layers accompanied with increase of the π/A hysteresis and of the elastic process contribution to π relaxation transients. Thus, MGS films of mammals with similar blinking frequency and TF stability have similar surface properties and stress relaxations unaltered by the interspecies MGS compositional variations. Such knowledge may impact the selection of animal mimics of human MGS and on a better understanding of lipid classes' impact on meibum functionality.

  14. The detection of pesticides in water using ZnCdSe quantum dot films

    Science.gov (United States)

    Bakar, N. A.; Salleh, M. M.; Umar, A. A.; Yahaya, M.

    2011-06-01

    This paper reports an attempt to develop a sensor system for detecting pesticides based on the effect of an analyte on the photoluminescence (PL) intensity of ZnCdSe quantum dot (QD) films. The ZnCdSe QDs were synthesized using a wet-chemical process. The sensor system comprises an excitation light source made of a laser diode, a dual arm fibre optic probe, a spectrometer and a sensor chamber. The QD films were deposited by dropping QD solution onto the probe surface and drying them at ambient temperature. The pesticides used in this study were Dipel, Siven 85% WP and Water-Dispersible Granules WG insecticides. The detection of pesticides was done by comparing the photoluminescence (PL) spectra of the films dipped in the deionized water and in pesticide solutions by varying the concentration of the pesticide solutions from 2.5 to 2500 μg l-1. It was observed that the PL intensity of the films was quenched by the presence of the pesticide molecules. The quenching degree increased with the concentration of the pesticide solutions. There is a linear relationship between the pesticide solution concentrations and the QD film sensor sensitivities. The sensitivity of the sensor system depended on the type of pesticides successively from the highest to lowest sensitivity in the order Siven 85% WP, Dipel and Water-Dispersible Granules WG. The QD films could be used as fluorescence sensors to detect water that is contaminated by pesticides.

  15. Designing icephobic surfaces by passively sustaining liquid film at ice-substrate interface

    Science.gov (United States)

    Zhao, Tom; Jones, Paul; Patankar, Neelesh

    2016-11-01

    Ice formation poses a significant barrier to transportation, energy generation and transport, gas extraction, etc. We propose to design icephobic surfaces that reduce ice formation and lower ice adhesion by sustaining a film of liquid water at the interface between bulk ice and the substrate. The liquid layer is in phase equilibrium with the surrounding bulk ice, and thus exists without constant energy input. Using molecular dynamic simulations, we show this liquid film can be maintained indefinitely by exploiting the phenomena of interfacial premelting and the freezing point depression of ice confined in surface texture due to the Gibbs Thomson effect. We demonstrate the reduction of both the work and strength of ice adhesion as a function of surface wettability and geometric parameters of the surface texture.

  16. Ellipsometry of clean surfaces, submonolayer and monolayer films

    NARCIS (Netherlands)

    Habraken, F.H.P.M.; Gijzeman, O.L.J.; Bootsma, G.A.

    1980-01-01

    The geometric and electronic structure of the surface region of a crystal is often different from the bulk structure and therefore the optical properties differ in principle also. Theories for the optical properties of (sub)monolayer films are compared, with special attention to anisotropic layers.

  17. Surface morphology of PS-PDMS diblock copolymer films

    DEFF Research Database (Denmark)

    Andersen, T.H.; Tougaard, S.; Larsen, N.B.

    2001-01-01

    Spin coated thin films (∼400 Å) of poly(styrene)–poly(dimethylsiloxane) (PS–PDMS) diblock copolymers have been investigated using X-ray Photoelectron Spectroscopy and Atomic Force Microscopy. Surface segregation of the poly(dimethylsiloxane) blocks was studied for five diblock copolymers which...

  18. Rewetting and Flow Film Boiling Along Hot Surface

    Institute of Scientific and Technical Information of China (English)

    王补宣Thermal Engineering Department; Tsinghua University; Beijing 100084; PRC; 彭晓峰

    1994-01-01

    The recent investigations on the rewettmg and film boiling of liquid flowing along a hot/heated surface are briefly reviewed and discussed.Some advanced theoretical analyses are conducted and new conclusions achieved.These investigations describe the fundamental characteristics of liquid flow boiling and further the complicated rewetting phenomena,and have resulted in considerable insight intothe mechanism.

  19. Hydrogen mediated transport of Sn to Ru film surface

    NARCIS (Netherlands)

    Faradzhev, N.; Sidorkin, V.

    2009-01-01

    The authors report on the interaction of atomic hydrogen with Sn and thin Ru film at room temperature. The study is done using a combination of photoelectron and low energy ion scattering spectroscopies as well as scanning electron microscopy. The adsorption of hydrogen on a Sn surface leads to the

  20. Hydrogen mediated transport of Sn to Ru film surface

    NARCIS (Netherlands)

    Faradzhev, N.; Sidorkin, V.

    2009-01-01

    The authors report on the interaction of atomic hydrogen with Sn and thin Ru film at room temperature. The study is done using a combination of photoelectron and low energy ion scattering spectroscopies as well as scanning electron microscopy. The adsorption of hydrogen on a Sn surface leads to the

  1. Experiments on the Flow of a Thin Liquid Film Over a Horizontal Stationary and Rotating Disk Surface

    Science.gov (United States)

    Ozar, B.; Cetegen, B. M.; Faghri, A.

    2003-01-01

    Experiments on characterization of thin liquid films flowing over stationary and rotating disk surfaces are described. The thin liquid film was created by introducing deionized water from a flow collar at the center of an aluminum disk with a known initial film thickness and uniform radial velocity. Radial film thickness distribution was measured using a non-intrusive laser light interface reflection technique that enabled the measurement of the instantaneous film thickness over a finite segment of the disk. Experiments were performed for a range of flow rates between 3.01pm and 15.01pm, corresponding to Reynolds numbers based on the liquid inlet gap height and velocity between 238 and 1,188. The angular speed of the disk was varied from 0 rpm to 300 rpm. When the disk was stationary, a circular hydraulic jump was present in the liquid film. The liquid-film thickness in the subcritical region (down-stream of the hydraulic jump) was an order of magnitude greater than that in the supercritical region (upstream of the hydraulic jump) which was of the order of 0.3 mm. As the Reynolds number increased, the hydraulic jump migrated toward the edge of the disk. In the case of rotation, the liquid-film thickness exhibited a maximum on the disk surface. The liquid-film inertia and friction influenced the inner region where the film thickness progressively increased. The outer region where the film thickness decreased was primarily affected by the centrifugal forces. A flow visualization study of the thin film was also performed to determine the characteristics of the waves on the free surface. At high rotational speeds, spiral waves were observed on the liquid film. It was also determined that the angle of the waves which form on the liquid surface was a function of the ratio of local radial to tangential velocity.

  2. Visualization of Surface Acoustic Waves in Thin Liquid Films

    OpenAIRE

    Rambach, R. W.; Taiber, J.; Scheck, C. M. L.; Meyer, C.; Reboud, J.; Cooper, Jonathan M.; Franke, T.

    2016-01-01

    We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with anWe demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfl...

  3. Epitaxial ferroelectric BiFeO{sub 3} thin films for unassisted photocatalytic water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Wei [Institute of Materials Research and Engineering (IMRE), A-STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore 119260 (Singapore); Yao, Kui; Lim, Yee-Fun; Suwardi, Ady [Institute of Materials Research and Engineering (IMRE), A-STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Liang, Yung C. [Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore 119260 (Singapore)

    2013-08-05

    Considering energy band alignment and polarization effect, ferroelectric BiFeO{sub 3} thin films are proposed as the photoanode in a monolithic cell to achieve unassisted photocatalytic water splitting. Significant anodic photocurrent was observed in our epitaxial ferroelectric BiFeO{sub 3} films prepared from sputter deposition. Both negative polarization charges and thinner films were found to promote the anodic photocatalytic reaction. Ultraviolet photoelectron spectroscopy proved that the conduction and valence band edges of BiFeO{sub 3} straddle the water redox levels. Theoretical analyses show that the large switchable polarization can modify the surface properties to promote the hydrogen and oxygen evolutions on the surfaces with positive and negative polarization charges, respectively.

  4. Epitaxial ferroelectric BiFeO3 thin films for unassisted photocatalytic water splitting

    Science.gov (United States)

    Ji, Wei; Yao, Kui; Lim, Yee-Fun; Liang, Yung C.; Suwardi, Ady

    2013-08-01

    Considering energy band alignment and polarization effect, ferroelectric BiFeO3 thin films are proposed as the photoanode in a monolithic cell to achieve unassisted photocatalytic water splitting. Significant anodic photocurrent was observed in our epitaxial ferroelectric BiFeO3 films prepared from sputter deposition. Both negative polarization charges and thinner films were found to promote the anodic photocatalytic reaction. Ultraviolet photoelectron spectroscopy proved that the conduction and valence band edges of BiFeO3 straddle the water redox levels. Theoretical analyses show that the large switchable polarization can modify the surface properties to promote the hydrogen and oxygen evolutions on the surfaces with positive and negative polarization charges, respectively.

  5. Experimental Study of Water Droplet Vaporization on Nanostructured Surfaces

    Science.gov (United States)

    Padilla, Jorge, Jr.

    This dissertation summarizes results of an experimental exploration of heat transfer during vaporization of a water droplet deposited on a nanostructured surface at a temperature approaching and exceeding the Leidenfrost point for the surface and at lower surface temperatures 10-40 degrees C above the saturated temperature of the water droplet at approximately 101 kPa. The results of these experiments were compared to those performed on bare smooth copper and aluminum surfaces in this and other studies. The nanostructured surfaces were composed of a vast array of zinc oxide (ZnO) nanocrystals grown by hydrothermal synthesis on a smooth copper substrate having an average surface roughness of approximately 0.06 micrometer. Various nanostructured surface array geometries were produced on the copper substrate by performing the hydrothermal synthesis for 4, 10 and 24 hours. The individual nanostructures were randomly-oriented and, depending on hydrothermal synthesis time, had a mean diameter of about 500-700 nm, a mean length of 1.7-3.3 micrometers,and porosities of approximately 0.04-0.58. Surface wetting was characterized by macroscopic measurements of contact angle based on the droplet profile and calculations based on measurements of liquid film spread area. Scanning electron microscope imaging was used to document the nanoscale features of the surface before and after the experiments. The nanostructured surfaces grown by hydrothermal synthesis for 4 and 24 hours exhibited contact angles of approximately 10, whereas the surfaces grown for 10 hours were superhydrophilic, exhibiting contact angles typically less than 3 degrees. In single droplet deposition experiments at 101 kPa, a high-speed video camera was used to document the droplet-surface interaction. Distilled and degassed water droplets ranging in size from 2.5-4.0 mm were deposited onto the surface from heights ranging from approximately 0.2-8.1 cm, such that Weber numbers spanned a range of approximately 0

  6. Water droplet behavior on superhydrophobic SiO{sub 2} nanocomposite films during icing/deicing cycles

    Energy Technology Data Exchange (ETDEWEB)

    Lazauskas, A., E-mail: Algirdas.LAZAUSKAS@stud.ktu.lt [Institute of Materials Science, Kaunas University of Technology, Savanorių 271, 3009 Kaunas (Lithuania); Guobienė, A., E-mail: Asta.GUOBIENE@ktu.lt [Institute of Materials Science, Kaunas University of Technology, Savanorių 271, 3009 Kaunas (Lithuania); Prosyčevas, I., E-mail: IGORPROS@mail.ru [Institute of Materials Science, Kaunas University of Technology, Savanorių 271, 3009 Kaunas (Lithuania); Baltrušaitis, V., E-mail: fei@fei.lt [Institute of Materials Science, Kaunas University of Technology, Savanorių 271, 3009 Kaunas (Lithuania); Grigaliūnas, V., E-mail: Viktoras.GRIGALIUNAS@ktu.lt [Institute of Materials Science, Kaunas University of Technology, Savanorių 271, 3009 Kaunas (Lithuania); Narmontas, P., E-mail: Pranas.NARMONTAS@ktu.lt [Institute of Materials Science, Kaunas University of Technology, Savanorių 271, 3009 Kaunas (Lithuania); Baltrusaitis, J., E-mail: j.baltrusaitis@utwente.nl [PhotoCatalytic Synthesis Group, University of Twente, Meander 229, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2013-08-15

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO{sub 2} nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO{sub 2} nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, water droplets on SiO{sub 2} nanocomposite film surface are subjected to a series of icing and deicing cycles in a humid (∼ 70% relative humidity) atmosphere and the resulting morphological changes are monitored and characterized using atomic force microscopy (AFM) and contact angle measurements. Our data show that the formation of the frozen or thawed water droplet, with no further shape change, on superhydrophobic SiO{sub 2} nanocomposite film, is obtained faster within each cycle as the number of the icing/deicing cycles increases. After 10 icing and deicing cycles, the superhydrophobic SiO{sub 2} nanocomposite film had a water contact angle value of 146 ± 2° which is effectively non-superhydrophobic. AFM analysis showed that the superhydrophobic SiO{sub 2} nanocomposite film surface area under the water droplet undergoes gradual mechanical damage during the repetitive icing/deicing cycles. We propose a possible mechanism of the morphological changes to the film surface that take place during the consecutive icing/deicing experiments. - Highlights: • Superhydrophobic film is subjected to repetitive icing/deicing treatments. • Water droplet shape transition is recorded and characterized thereafter. • Atomic force microscopy and contact angle measurements are performed. • The surface undergoes gradual mechanical damage during repetitive icing/deicing. • Mechanism for the observed surface morphological changes is suggested.

  7. Lipases efficiently stearate and cutinases acetylate the surface of arabinoxylan films

    OpenAIRE

    Stepan, A. M.; Anasontzis, G. E.; Matamá, Maria Teresa; Paulo, Artur Cavaco; Olsson, L; Gatenholm, P.

    2013-01-01

    This is the first report on successful enzyme catalyzed surface esterification of hemicellulose films. Enzyme catalyzed surface acetylation with vinyl acetate and stearation with vinyl stearate were studied on rye arabinoxylan (AX) films. Different surface analytical techniques (FT-IR, TOF-SIMS, ESCA, CA) show that lipases from Mucor javanicus, Rhizopus oryzae and Candida rugosa successfully surface stearate AX films and that a cutinase from Fusarium solani pisi surface acetylates these films...

  8. Preliminary indications from atomic force microscopy of the presence of rapidly-formed nanoscale films on aquifer material surfaces

    Science.gov (United States)

    Gaebel, Claudia; Lead, Jamie R.; Renshaw, Joanna C.; Tellam, John H.

    2009-08-01

    The objective of this study was to determine if there is a nanoscale surface film on aquifer-like materials exposed to deep groundwaters, as has previously been found on surfaces exposed to surface and soil waters. Such surface films will modify surface properties that are so important in determining the mobility of many groundwater pollutants. Muscovite mica was used because a) it is a good analogue for the main sorbing phases of many clastic aquifers and b) its cleavage planes are atomically flat allowing high resolution imaging. Freshly-cleaved muscovite plates were exposed to groundwater from a sandstone aquifer for 30 min, and surface properties (morphology, coverage, roughness and tip-substrate force interactions) were measured using atomic force microscopy (AFM). A patchy surface film of several nanometres in depth, incorporating larger separate particles, was found on the mica surface. This film was associated with significantly increased roughness values and AFM probe-sample interaction forces compared with pure water and inorganic (synthetic groundwater) solution controls. Although the results reported are preliminary in nature, if confirmed, such films are likely to affect sorption reactions, surface-facilitated redox interactions, non-aqueous phase liquid wetting angles, and colloid-pathogen-rock attachment, and will thus be of importance in understanding natural attenuation and migration of dissolved, non-aqueous and particulate phases in groundwaters.

  9. SURFACE WATER QUALITY IN THE RIVER PRUT

    Directory of Open Access Journals (Sweden)

    MIHAELA DUMITRAN

    2011-03-01

    Full Text Available Water is an increasingly important and why it is important to surfacewater quality, which is given by the analysis of physical - chemical, biological andobserving the investigation of water, biota, environments investigation. Analysis ofthe Prut river in terms of biological and physical elements - chemical. Evaluationof ecological and chemical status of water was done according to order of approvalof the standard classification nr.161/2006 surface water to determine the ecologicalstatus of water bodies

  10. Surface Structure of Thin Films of Multifunctional Ionizable Copolymers

    Science.gov (United States)

    Wickramasinghe, Anuradhi; Perahia, Dvora

    Phase segregation results in a rich variety of structures in co-polymers where interfacial forces often dominate the structure of thin films. Introduction of ionizable segments often drives the formation of compounded structures with multiple blocks residing at the interfaces. Here we probe thin films, 40-50nm, of an A-B-C-B-A co-polymer where C is a randomly sulfonated polystyrene with sulfonation fractions of 0, 26 and 52 mole %, B is poly (ethylene-r-propylene), and A is poly (t-butyl styrene) as the sulfonation level and temperature are varied using Neutron Reflectivity AFM, and surface tension measurements. As cast films form layers with both hydrophobic blocks dominating the solid and air interfaces and the ionizable block segregating to the center. Following annealing at 1700C, above Tg of styrene sulfonate, the films coarsen, with surface aggregation dominating the structure, though interfacial regions remain dominated by the hydrophobic segments. We show that in contrast to non-ionic co-polymers, formation of micelles dominated the structure of these ionic structured films. Supported in part by DOE Grant No. DE-SC007908.

  11. Surface Modification of Polyethylene (PE) Films Using Dielectric Barrier Discharge Plasma at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    WANG Kun; LI Jian; REN Chunsheng; WANG Dezhen; WANG Younian

    2008-01-01

    Modification of the surface properties of polyethylene (PE) films is studied using air dielectric barrier discharge at atmospheric pressure. The treated samples are examined by water contact angle measurements, Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). With the increase in treating time, the water contact angle changes from 93.2° before treatment to a minimum of 53.3° after a treatment for 50 s. Both ATR and XPS results show some oxidized" species are introduced into the sample surface by the plasma treatment and the tendency of the water contact angle with the treating time is the same as that of oxygen concentration on the treated sample surface. SEM result shows the surface roughness of PE samples increases with the treatment time increasing.

  12. Surfactant controlled switching of water-in-oil wetting behaviour of porous silica films grown at oil-water interfaces

    Indian Academy of Sciences (India)

    Manish M Kulkarni; Rajdip Bandyopadhyaya; Ashutosh Sharma

    2008-11-01

    Selective permeation of oil and water across a porous medium, as in oil recovery operations, depends on the preferential wetting properties of the porous medium. We show a profound influence of surfactants in wetting of porous media and thus demonstrate a new route for the control of water-in-oil wetting of porous substrates by changing the concentration of surfactants in an aqueous sub-phase below the substrate. This strategy is employed to engineer partial reversible wetting transitions on a porous silica film. The film itself is grown and stabilized on a flat, macroscopic interface between an oil phase and an aqueous sub-phase. On increasing the surfactant (CTAB) concentration in the sub-phase, contact angle of a water drop (placed on the oil side of the film) changes from 140° to 16° in 25 min by diffusion of the surfactant across the porous film. On further replacement of the sub-phase with pure water, diffusion of the surfactant from the water drop back to the sub-phase was slower, increasing the contact angle in the process from 16° to 90° in 2 h. Wettability control by a cationic surfactant (CTAB) was found to be much faster (6 deg/min) than that offered by an anionic surfactant, SDS (0.05 deg/min). Switching of the surface wettability due to the surfactant diffusion may have implications in oil-water separation, chemical bed reactors and microfluidic devices.

  13. Thickness effects of water overlayer on its explosive evaporation at heated metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Dou Yusheng E-mail: ysd@chem.psu.edu; Zhigilei, Leonid V.; Postawa, Zbigniew; Winograd, Nicholas; Garrison, Barbara J

    2001-06-01

    Molecular dynamics (MD) simulations have been employed to investigate the effect of the thickness of a water overlayer on the character of its ejection from a heated Au surface. The simulations are performed for five systems differing in the thickness of the water overlayer which was adsorbed on a metal substrate heated to 1000 K. For each system, an explosive evaporation occurs in the part of the water film adjacent to the metal surface and the upper part of the film is pushed off by the generated force. The average maximum temperature of the water film decreases as the film thickness increases. In contrast, the temperature achieved by the fast cooling due to the explosive evaporation shows an inverse trend. The significance of these model calculations to matrix-assisted laser desorption and ionization (MALDI) mass spectrometry is discussed.

  14. Marangoni spreading due to a localized alcohol supply on a thin water film

    CERN Document Server

    Hernández-Sánchez, José Federico; Snoeijer, J H

    2013-01-01

    Bringing the interfaces of two miscible fluids into contact naturally generates strong gradients in surface tension. Here we investigate such a Marangoni-driven flow by continuously supplying isopropyl alcohol (IPA) on a film of water, using micron-sized droplets of IPA-water mixtures. These droplets create a localized depression in surface tension that leads to the opening of a circular and thin region in the water film. At the edge of the thin region, there is a rim growing and collecting the water of the film. We find that the spreading radius scales as $r \\sim t^{1/2}$. This result can be explained from a balance between Marangoni and viscous stresses, assuming that the gradients in surface tension are smoothened out over the entire size of the circular opening. We derive a scaling law that accurately predicts the influence of the IPA flux as well as the thickness of the thin film at the interior of the spreading front.

  15. Water-Induced Blister Formation in a Thin Film Polymer

    NARCIS (Netherlands)

    Berkelaar, R.P.; Bampoulis, Pantelis; Dietrich, E.; Jansen, H.P.; Zhang, Xuehua; Kooij, Ernst S.; Lohse, Detlef; Zandvliet, Henricus J.W.

    2015-01-01

    A failure mechanism of thin film polymers immersed in water is presented: the formation of blisters. The growth of blisters is counterintuitive as the substrates were noncorroding and the polymer does not swell in water. We identify osmosis as the driving force behind the blister formation. The

  16. Water induced blister formation in a thin film polymer

    NARCIS (Netherlands)

    Berkelaar, R.P.; Bampoulis, Pantelis; Dietrich, E.; Jansen, H.P.; Zhang, Xuehua; Kooij, Ernst S.; Lohse, Detlef; Zandvliet, Henricus J.W.

    2015-01-01

    A failure mechanism of thin film polymers immersed in water is presented: the formation of blisters. The growth of blisters is counterintuitive as the substrates were noncorroding and the polymer does not swell in water. We identify osmosis as the driving force behind the blister formation. The

  17. Water-Induced Blister Formation in a Thin Film Polymer

    NARCIS (Netherlands)

    Berkelaar, R.P.; Bampoulis, P.; Dietrich, E.; Jansen, H.P.; Zhang, X.; Kooij, E.S.; Lohse, D.; Zandvliet, Harold J.W.

    2015-01-01

    A failure mechanism of thin film polymers immersed in water is presented: the formation of blisters. The growth of blisters is counterintuitive as the substrates were noncorroding and the polymer does not swell in water. We identify osmosis as the driving force behind the blister formation. The dyna

  18. Water induced blister formation in a thin film polymer

    NARCIS (Netherlands)

    Berkelaar, R.P.; Bampoulis, P.; Dietrich, E.; Jansen, H.P.; Zhang, Xuehua; Kooij, E.S.; Lohse, D.; Zandvliet, H.J.W.

    2015-01-01

    A failure mechanism of thin film polymers immersed in water is presented: the formation of blisters. The growth of blisters is counterintuitive as the substrates were noncorroding and the polymer does not swell in water. We identify osmosis as the driving force behind the blister formation. The dyna

  19. Surface plasmon resonance in nanocrystalline gold-copper alloy films.

    Science.gov (United States)

    Hussain, S; Datta, Subhadeep; Roy, R K; Pal, A K

    2007-12-01

    Nanocrystalline Au(x)Cu(1-x) films were synthesized by depositing Cu/Au/Cu multilayer in nanocrystalline thin film form with requisite thickness of individual layers onto fused silica substrates by high pressure sputtering technique. The absorbance spectra showed only one surface plasmon peak for all the compositions with the exception that the peak position did not indicate gradual shift as gold concentration was increased. Peak position for the two compositions corresponding to the two superlattice structures, AuCu3 and AuCu, deviated significantly from linear variation. The experimental results have been discussed in light of the existing Mie theory and the Core-shell model.

  20. Sugar-fiber Imprinting to Generate Microgrooves on Polymeric Film Surfaces for Contact Guidance of Cells

    Institute of Scientific and Technical Information of China (English)

    屈泽华; 丁建东

    2012-01-01

    Anisotropic surface topography is known to induce the contact guidance of cells, and facile and biocompatible approaches of the physical modification of the pertinent matrix surfaces are thus meaningful for biomaterials. Herein, we put forward a sugar-fiber imprinting technique to generate microgrooves on hydrophobic polymers demonstrated by the poly(lactic-eo-glycolic acid) (PLGA) films. Microgrooves were conveniently generated after removing sugar fibers simply by water. The resulting locally anisotropic microgrooves were confirmed to elongate the cells cultured on the surface.

  1. Surface of Alumina Films after Prolonged Breakdowns in Galvanostatic Anodization

    Directory of Open Access Journals (Sweden)

    Christian Girginov

    2011-01-01

    Full Text Available Breakdown phenomena are investigated at continuous isothermal (20∘C and galvanostatic (0.2–5 mA cm−2 anodizing of aluminum in ammonium salicylate in dimethylformamide (1 M AS/DMF electrolyte. From the kinetic (-curves, the breakdown voltage ( values are estimated, as well as the frequency and amplitude of oscillations of formation voltage ( at different current densities. The surface of the aluminum specimens was studied using atomic force microscopy (AFM. Data on topography and surface roughness parameters of the electrode after electric breakdowns are obtained as a function of anodization time. The electrode surface of anodic films, formed with different current densities until the same charge density has passed (2.5 C cm−2, was assessed. Results are discussed on the basis of perceptions of avalanche mechanism of the breakdown phenomena, due to the injection of electrons and their multiplication in the volume of the film.

  2. Forming lipid bilayer membrane arrays on micropatterned polyelectrolyte film surfaces.

    Science.gov (United States)

    Zhang, Ying; Wang, Lei; Wang, Xuejing; Qi, Guodong; Han, Xiaojun

    2013-07-01

    A novel method of forming lipid bilayer membrane arrays on micropatterned polyelectrolyte film surfaces is introduced. Polyelectrolyte films were fabricated by the layer-by-layer technique on a silicon oxide surface modified with a 3-aminopropyltriethoxysilane (APTES) monolayer. The surface pK(a) value of the APTES monolayer was determined by cyclic voltammetry to be approximately 5.61, on the basis of which a pH value of 2.0 was chosen for layer-by-layer assembly. Micropatterned polyelectrolyte films were obtained by deep-UV (254 nm) photolysis though a mask. Absorbed fluorescent latex beads were used to visualize the patterned surfaces. Lipid bilayer arrays were fabricated on the micropatterned surfaces by immersing the patterned substrates into a solution containing egg phosphatidylcholine vesicles. Fluorescence recovery after photobleaching studies yielded a lateral diffusion coefficient for probe molecules of 1.31±0.17 μm(2) s(-1) in the bilayer region, and migration of the lipid NBD PE in bilayer lipid membrane arrays was observed in an electric field.

  3. Efficient photoelectrochemical water splitting over anodized p-type NiO porous films.

    Science.gov (United States)

    Hu, Chenyan; Chu, Kenneth; Zhao, Yihua; Teoh, Wey Yang

    2014-11-12

    NiO photocathodes were fabricated by alkaline etching-anodizing nickel foil in an organic-based electrolyte. The resulting films have a highly macroporous surface structure due to rapid dissolution of the oxide layer as it is formed during the anodization process. We are able to control the films' surface structures by varying the anodization duration and voltage. With an onset potential of +0.53 V versus the reversible hydrogen electrode (RHE), the photocurrent efficiency of the NiO electrodes showed dependencies on their surface roughness factor, which determines the extent of semiconductor-electrolyte interface and the associated quality of the NiO surface sites. A maximum incident photon-to-current conversion efficiency (IPCE(max)) of 22% was obtained from NiO film with a roughness factor of 8.4. Adding an Al2O3 blocking layer minimizes surface charge recombination on the NiO and hence increased the IPCE(max) to 28%. The NiO/Al2O3 films were extremely stable during photoelectrochemical water splitting tests lasting up to 20 h, continuously producing hydrogen and oxygen in the stoichiometric 2:1 ratio. The NiO/Al2O3 and NiO films fabricated using the alkaline anodization process produced 12 and 6 times as much hydrogen, respectively, as those fabricated using commercial NiO nanoparticles.

  4. 21 CFR 177.1400 - Hydroxyethyl cellulose film, water-insoluble.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxyethyl cellulose film, water-insoluble. 177... cellulose film, water-insoluble. Water-insoluble hydroxyethyl cellulose film may be safely used for... cellulose film consists of a base sheet manufactured by the ethoxylation of cellulose under...

  5. Manufacturing and characterisation of water repellent surfaces

    DEFF Research Database (Denmark)

    De Grave, Arnaud; Botija, Pablo; Hansen, Hans Nørgaard

    2006-01-01

    design criteria for such surfaces. The problem of adapting this behaviour to artificially roughened surfaces is addressed by providing design criteria for superhydrophobic, water-repellent and self-cleaning surfaces according to the concrete performance desired for them. Different kind of manufacturing...

  6. Deposition of Ultrathin Nano-Hydroxyapatite Films on Laser Micro-Textured Titanium Surfaces to Prepare a Multiscale Surface Topography for Improved Surface Wettability/Energy

    Directory of Open Access Journals (Sweden)

    Maria Surmeneva

    2016-10-01

    Full Text Available The primary aim of this study was to analyse the correlation between topographical features and chemical composition with the changes in wettability and the surface free energy of microstructured titanium (Ti surfaces. Periodic microscale structures on the surface of Ti substrates were fabricated via direct laser interference patterning (DLIP. Radio-frequency magnetron sputter deposition of ultrathin nanostructured hydroxyapatite (HA films was used to form an additional nanoscale grain morphology on the microscale-structured Ti surfaces to generate multiscale surface structures. The surface characteristics were evaluated using atomic force microscopy and contact angle and surface free energy measurements. The structure and phase composition of the HA films were investigated using X-ray diffraction. The HA-coated periodic microscale structured Ti substrates exhibited a significantly lower water contact angle and a larger surface free energy compared with the uncoated Ti substrates. Control over the wettability and surface free energy was achieved using Ti substrates structured via the DLIP technique followed by the deposition of a nanostructured HA coating, which resulted in the changes in surface chemistry and the formation of multiscale surface topography on the nano- and microscale.

  7. Preparation of enhanced hydrophobic poly(L-lactide-co-ε-caprolactone) films surface and its blood compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Il; Lim, Jin Ik; Jung, Youngmee; Mun, Cho Hay [Division of Life and Health Science, Biomaterials Research Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Kim, Ji Heung, E-mail: kimjh@skku.edu [Department of Chemical Engineering, Polymer Technology Institute, Sungkyunkwan University, Suwon, Kyunggi (Korea, Republic of); Kim, Soo Hyun, E-mail: soohkim@kist.re.kr [Division of Life and Health Science, Biomaterials Research Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul (Korea, Republic of)

    2013-07-01

    Hydrophobicity-enhanced poly(L-lactide-co-ε-caprolactone) (PLCL) (50:50) films were cast by using the solvent–nonsolvent casting method. PLCL (50:50) was synthesized by the well-known random copolymerization process and confirmed by {sup 1}H NMR analysis. The molecular weight of the synthesized PLCL was measured by gel permeation chromatography (GPC). Number-average (Mn), weight-average (Mw) molecular weights and polydispersity (Mw/Mn) were 7 × 10{sup 4}, 1.2 × 10{sup 5}, and 1.7, respectively. PLCL films were cast in vacuum condition with various nonsolvents and nonsolvent ratios. Tetrahydrofuran (THF) was used as the solvent and three different alcohols were used as the nonsolvent: methanol, ethanol, and isopropyl alcohol (IPA). Surface hydrophobicity was confirmed by water contact angle. The water contact angle was increased from 81° ± 2° to 107° ± 2°. Water contact angle was influenced by surface porosity and topography. The prepared film surfaces were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The change of crystalline property was characterized by X-ray diffraction (XRD). Platelet adhesion tests on the modified PLCL film surfaces were evaluated by platelet-rich plasma (PRP). The modified film surface exhibited enhanced hydrophobicity and reduced platelet adhesion ratio depending on the surface topography. One of the candidate products proposed as a potential blood compatible material showed a markedly reduced platelet adhesion property.

  8. Preparation of enhanced hydrophobic poly(L-lactide-co-ɛ-caprolactone) films surface and its blood compatibility

    Science.gov (United States)

    Kim, Seung Il; Lim, Jin Ik; Jung, Youngmee; Mun, Cho Hay; Kim, Ji Heung; Kim, Soo Hyun

    2013-07-01

    Hydrophobicity-enhanced poly(L-lactide-co-ɛ-caprolactone) (PLCL) (50:50) films were cast by using the solvent-nonsolvent casting method. PLCL (50:50) was synthesized by the well-known random copolymerization process and confirmed by 1H NMR analysis. The molecular weight of the synthesized PLCL was measured by gel permeation chromatography (GPC). Number-average (Mn), weight-average (Mw) molecular weights and polydispersity (Mw/Mn) were 7 × 104, 1.2 × 105, and 1.7, respectively. PLCL films were cast in vacuum condition with various nonsolvents and nonsolvent ratios. Tetrahydrofuran (THF) was used as the solvent and three different alcohols were used as the nonsolvent: methanol, ethanol, and isopropyl alcohol (IPA). Surface hydrophobicity was confirmed by water contact angle. The water contact angle was increased from 81° ± 2° to 107° ± 2°. Water contact angle was influenced by surface porosity and topography. The prepared film surfaces were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The change of crystalline property was characterized by X-ray diffraction (XRD). Platelet adhesion tests on the modified PLCL film surfaces were evaluated by platelet-rich plasma (PRP). The modified film surface exhibited enhanced hydrophobicity and reduced platelet adhesion ratio depending on the surface topography. One of the candidate products proposed as a potential blood compatible material showed a markedly reduced platelet adhesion property.

  9. Surface Water Quality Monitoring Sites

    Data.gov (United States)

    Minnesota Department of Natural Resources — The MN Department of Agriculture (MDA) is charged with periodically collecting and analyzing water samples from selected locations throughout the state to determine...

  10. Surface Grafting of Phenolic Resole onto LDPE Films

    Institute of Scientific and Technical Information of China (English)

    Jue CHENG; Yi ZHENG; Wan Tai YANG

    2006-01-01

    Low density polyethylene film surface-grafted phenolic resole was prepared by a sequential processes. Firstly, acrylic acid was grafted to the surface of low density polyethylene by photo-grafting. Secondly, the carboxylic groups in poly(acrylic acid) chains were transferred to sulfonic groups by the reaction of carboxylic groups with sulfanilic acid. Finally, a thin layer of phenolic resole was cured onto the surface of low density polyethylene. The grafting process was characterized by FTIR-ATR and gravimetric analysis. A possible model was proposed to interpret the experimental results.

  11. Surface scattering mechanisms of tantalum nitride thin film resistor.

    Science.gov (United States)

    Chen, Huey-Ru; Chen, Ying-Chung; Chang, Ting-Chang; Chang, Kuan-Chang; Tsai, Tsung-Ming; Chu, Tian-Jian; Shih, Chih-Cheng; Chuang, Nai-Chuan; Wang, Kao-Yuan

    2014-01-01

    In this letter, we utilize an electrical analysis method to develop a TaN thin film resistor with a stricter spec and near-zero temperature coefficient of resistance (TCR) for car-used electronic applications. Simultaneously, we also propose a physical mechanism mode to explain the origin of near-zero TCR for the TaN thin film resistor (TFR). Through current fitting, the carrier conduction mechanism of the TaN TFR changes from hopping to surface scattering and finally to ohmic conduction for different TaN TFRs with different TaN microstructures. Experimental data of current-voltage measurement under successive increasing temperature confirm the conduction mechanism transition. A model of TaN grain boundary isolation ability is eventually proposed to influence the carrier transport in the TaN thin film resistor, which causes different current conduction mechanisms.

  12. Improvement in physical and biological properties of chitosan/soy protein films by surface grafted heparin.

    Science.gov (United States)

    Wang, Xiaomei; Hu, Ling; Li, Chen; Gan, Li; He, Meng; He, Xiaohua; Tian, Weiqun; Li, Mingming; Xu, Li; Li, Yinping; Chen, Yun

    2016-02-01

    A series of chitosan/soy protein isolate (SPI) composite films (CS-n, n=0, 10 and 30, corresponding to SPI content in the composites) were prepared. Heparin was grafted onto the surface of CS-n to fabricate a series of heparinized films (HCS-n). CS-n and HCS-n were characterized by ATR-Fourier transform infrared spectroscopy and water contact angle. The surface heparin density was measured by toluidine blue assay. The results showed that heparin has been successfully grafted onto the surface of CS-n. Heparin evenly distributed on the surface of the films and the heparin content increased with the increase of SPI content, and the hydrophilicity of the films was enhanced due to the grafted heparin. The cytocompatibility and hemocompatibility of CS-n and HCS-n were evaluated by cell culture (MTT assay, live/dead assay, cell morphology and cell density observation), platelet adhesion test, plasma recalcification time (PRT) measurement, hemolysis assay and thrombus formation test. HCS-n showed higher cell adhesion rate and improved cytocompatibility compared to the corresponding CS-n. HCS-n also exhibited lower platelet adhesion, longer PRT, higher blood anticoagulant indexes (BCI) and lower hemolysis rate than the corresponding CS-n. The improved cytocompatibility and hemocompatibility of HCS-n would shed light on the potential applications of chitosan/soy protein-based biomaterials that may come into contact with blood.

  13. Electrochemically polymerized conjugated polymer films: Stability improvement and surface functionalization

    Science.gov (United States)

    Wei, Bin

    Conjugated polymers have been widely used in various applications including organic solar cells, electrochromic devices, chemical sensors, and biomedical devices. Poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives have received considerable interest because of their low oxidation potential, relatively high chemical stability, and high conductivity. Electrochemical deposition is a convenient method for precisely fabricating conjugated polymer thin films. Here, we report the stability improvement and surface functionalization of electrochemically polymerized PEDOT films. The long-term performance of PEDOT coatings is limited by their relatively poor stability on various inorganic substrates. Two different methods were used to improve the stability of PEDOT coatings, one involved using carboxylic acid functionalized EDOT (EDOT-acid) as adhesion promoter. EDOT-acid molecules were chemically bonded onto activated metal oxide substrates via chemisorption. PEDOT was then polymerized onto the EDOT-acid modified substrates, forming covalently bonded coatings. An aggressive ultrasonication test confirmed the significantly improved adhesion of the PEDOT films on electrodes with EDOT-acid treatment over those without treatment. The other method was to use an octa-ProDOT-functionalized POSS derivative (POSSProDOT) as cross-linker. PEDOT copolymer films were electrochemically deposited with various concentrations of POSS-ProDOT. The optical, morphological and electrochemical properties of the copolymer films could be systematically tuned with the incorporation of POSS-ProDOT. Significantly enhanced electrochemical and mechanical stability of the copolymers were observed at intermediate levels of POSS-ProDOT content (3.1 wt%) via chronic stimulation tests. Surface functionalization of conducting polymer films provides a potential means for systematically tailoring their chemical and physical properties. We have synthesized, polymerized and characterized a dialkene

  14. Three-dimensional radiochromic film dosimetry for volumetric modulated arc therapy using a spiral water phantom.

    Science.gov (United States)

    Tanooka, Masao; Doi, Hiroshi; Miura, Hideharu; Inoue, Hiroyuki; Niwa, Yasue; Takada, Yasuhiro; Fujiwara, Masayuki; Sakai, Toshiyuki; Sakamoto, Kiyoshi; Kamikonya, Norihiko; Hirota, Shozo

    2013-11-01

    We validated 3D radiochromic film dosimetry for volumetric modulated arc therapy (VMAT) using a newly developed spiral water phantom. The phantom consists of a main body and an insert box, each of which has an acrylic wall thickness of 3 mm and is filled with water. The insert box includes a spiral film box used for dose-distribution measurement, and a film holder for positioning a radiochromic film. The film holder has two parallel walls whose facing inner surfaces are equipped with spiral grooves in a mirrored configuration. The film is inserted into the spiral grooves by its side edges and runs along them to be positioned on a spiral plane. Dose calculation was performed by applying clinical VMAT plans to the spiral water phantom using a commercial Monte Carlo-based treatment-planning system, Monaco, whereas dose was measured by delivering the VMAT beams to the phantom. The calculated dose distributions were resampled on the spiral plane, and the dose distributions recorded on the film were scanned. Comparisons between the calculated and measured dose distributions yielded an average gamma-index pass rate of 87.0% (range, 91.2-84.6%) in nine prostate VMAT plans under 3 mm/3% criteria with a dose-calculation grid size of 2 mm. The pass rates were increased beyond 90% (average, 91.1%; range, 90.1-92.0%) when the dose-calculation grid size was decreased to 1 mm. We have confirmed that 3D radiochromic film dosimetry using the spiral water phantom is a simple and cost-effective approach to VMAT dose verification.

  15. Control of hydrophobic surface and wetting states in ultra-flat ZnO films by GLAD method

    Science.gov (United States)

    Chi, Po-Wei; Su, Chih-Wei; Wei, Da-Hua

    2017-05-01

    Ultra-flat Zinc oxide (ZnO) films with natural hydrophobicity were sputtered onto glass substrates by glancing angle deposition (GLAD) method without addition of active oxygen at room temperature under different glancing angles relating to the sample holder. The sample holder was positioned at glancing angles of 0° and 30°, and the sputtering power was fixed at 75 W with low argon (Ar) pressure of 1 × 10-2 Torr during deposition process. According to analysis of surface composition and structure, the naturally hydrophobic wetting state can be attributed to the different grain structure and hydrocarbon adsorbates on the top of the film surface. On the other hand, the interfacial water molecules near the surface of ultra-flat ZnO films are confirmed belong to the hydrophobic hydrogen structure by Fourier transform infrared/attenuated total reflection. In addition, the water contact angle was significantly improved by a simple factor of glancing angle. The water contact angle value of ultra-flat ZnO films increased from 90° to 98° while the sample holder is with glancing angle of 30°. Moreover, our present ultra-flat ZnO films also exhibited excellent transparency over 80%, and the surface wetting switched from hydrophobic to hydrophilic states after exposing in ultraviolet (UV) surroundings. Then, the ZnO films could be freely and stably reversed back to hydrophobicity after stored in dark surroundings. This present study not only demonstrates that the natural wettability of ultra-flat ZnO films is strongly associated with surface composition and structure, but also provides an easy way to modulate and improve the surface wettability. This also extends the potential applications of ultra-flat ZnO thin films and aids a profound understanding for device design and material development.

  16. Polydopamine Films from the Forgotten Air/Water Interface.

    Science.gov (United States)

    Ponzio, Florian; Payamyar, Payam; Schneider, Anne; Winterhalter, Mathias; Bour, Jérôme; Addiego, Frédéric; Krafft, Marie-Pierre; Hemmerle, Joseph; Ball, Vincent

    2014-10-02

    The formation of polydopamine under mild oxidation conditions from dopamine solutions with mechanical agitation leads to the formation of films that can functionalize all kinds of materials. In the absence of stirring of the solution, we report the formation of polydopamine films at the air/water interface (PDA A/W) and suggest that it arises from an homogeneous nucleation process. These films grow two times faster than in solution and can be deposited on hydrophilic or hydrophobic substrates by the Langmuir-Schaeffer technique. Thanks to this new method, porous and hydrophobic materials like polytetrafluoroethylene (PTFE) membranes can be completely covered with a 35 nm thick PDA A/W film after only 3h of reaction. Finally the oxidation of a monomer followed by a polymerization in water is not exclusive to polydopamine since we also transferred polyaniline functional films from the air/water interface to solid substrates. These findings suggest that self-assembly from a solution containing hydrophilic monomers undergoing a chemical transformation (here oxidation and oligomerization) could be a general method to produce films at the liquid/air interface.

  17. Protein film photoelectrochemistry of the water oxidation enzyme photosystem II.

    Science.gov (United States)

    Kato, Masaru; Zhang, Jenny Z; Paul, Nicholas; Reisner, Erwin

    2014-09-21

    Photosynthesis is responsible for the sunlight-powered conversion of carbon dioxide and water into chemical energy in the form of carbohydrates and the release of O2 as a by-product. Although many proteins are involved in photosynthesis, the fascinating machinery of Photosystem II (PSII) is at the heart of this process. This tutorial review describes an emerging technique named protein film photoelectrochemistry (PF-PEC), which allows for the light-dependent activity of PSII adsorbed onto an electrode surface to be studied. The technique is straightforward to use, does not require highly specialised and/or expensive equipment, is highly selective for the active fractions of the adsorbed enzyme, and requires a small amount of enzyme sample. The use of PF-PEC to study PSII can yield insights into its activity, stability, quantum yields, redox behaviour, and interfacial electron transfer pathways. It can also be used in PSII inhibition studies and chemical screening, which may prove useful in the development of biosensors. PSII PF-PEC cells also serve as proof-of-principle solar water oxidation systems; here, a comparison is made against PSII-inspired synthetic photocatalysts and materials for artificial photosynthesis.

  18. Surface plasmon enhanced photoluminescence in amorphous silicon carbide films by adjusting Ag island film sizes

    Institute of Scientific and Technical Information of China (English)

    Yu Wei; Wang Xin-Zhan; Dai Wan-Lei; Lu Wan-Bing; Liu Yu-Mei; Fu Guang-Sheng

    2013-01-01

    Ag island films with different sizes are deposited on hydrogenated amorphous silicon carbide (α-SiC∶H) films,and the influences of Ag island films on the optical properties of the α-SiC∶H films are investigated.Atomic force microscope images show that Ag nanoislands are formed after Ag coating,and the size of the Ag islands increases with increasing Ag deposition time.The extinction spectra indicate that two resonance absorption peaks which correspond to out-of-plane and in-plane surface plasmon modes of the Ag island films are obtained,and the resonance peak shifts toward longer wavelength with increasing Ag island size.The photoluminescence (PL) enhancement or quenching depends on the size of Ag islands,and PL enhancement by 1.6 times on the main PL band is obtained when the sputtering time is 10 min.Analyses show that the influence of surface plasmons on the PL of α-SiC:H is determined by the competition between the scattering and absorption of Ag islands,and PL enhancement is obtained when scattering is the main interaction between the Ag islands and incident light.

  19. Cell adhesion and growth on ultrananocrystalline diamond and diamond-like carbon films after different surface modifications

    Energy Technology Data Exchange (ETDEWEB)

    Miksovsky, J. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Voss, A. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Kozarova, R. [Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia (Bulgaria); Kocourek, T.; Pisarik, P. [Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Ceccone, G. [Unit Nanobiosciences, European Commission Joint Research Centre, Ispra (Italy); Kulisch, W. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Jelinek, M. [Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Apostolova, M.D. [Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia (Bulgaria); Reithmaier, J.P. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Popov, C., E-mail: popov@ina.uni-kassel.de [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany)

    2014-04-01

    Graphical abstract: - Highlights: • UNCD and DLC films were modified by UV/O{sub 3} treatments, O{sub 2} or NH{sub 3}-containing plasmas. • Surface composition, wettability and surface energy change upon modifications. • Higher efficiency of UNCD modifications was observed. • Cell attachment and growth were influenced by the surface termination and roughness. - Abstract: Diamond and diamond-like carbon (DLC) films possess a set of excellent physical and chemical properties which together with a high biocompatibility make them attractive candidates for a number of medical and biotechnological applications. In the current work thin ultrananocrystalline diamond (UNCD) and DLC films were comparatively investigated with respect to cell attachment and proliferation after different surface modifications. The UNCD films were prepared by microwave plasma enhanced chemical vapor deposition, the DLC films by pulsed laser deposition (PLD). The films were comprehensively characterized with respect to their basic properties, e.g. crystallinity, morphology, chemical bonding nature, etc. Afterwards the UNCD and DLC films were modified applying O{sub 2} or NH{sub 3}/N{sub 2} plasmas and UV/O{sub 3} treatments to alter their surface termination. The surface composition of as-grown and modified samples was studied by X-ray photoelectron spectroscopy (XPS). Furthermore the films were characterized by contact angle measurements with water, formamide, 1-decanol and diiodomethane; from the results obtained the surface energy with its dispersive and polar components was calculated. The adhesion and proliferation of MG63 osteosarcoma cells on the different UNCD and DLC samples were assessed by measurement of the cell attachment efficiency and MTT assays. The determined cell densities were compared and correlated with the surface properties of as-deposited and modified UNCD and DLC films.

  20. Picosecond laser induced periodic surface structure on copper thin films

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, Thi Trang Dai; Petit, Agnès; Semmar, Nadjib, E-mail: nadjib.semmar@univ-orleans.fr

    2014-05-01

    LIPSS (Laser Induced Periodic Surface Structure) formation on copper thin films induced by a picosecond laser beam (Nd:YAG laser at 266 nm, 42 ps and 10 Hz) was studied experimentally. Copper thin films were deposited on glass and silicon substrates by magnetron sputtering. The surface modifications of irradiated zones were analyzed by scanning electron microscopy. Two distinct types of LIPSS were identified with respect to the laser fluence (F), number of laser shots (N) and substrate material. Namely, with a number of laser shots (1000 < N < 10,000) and a fluence of (200 mJ/cm{sup 2} < F < 500 mJ/cm{sup 2}), Low Spatial Frequency LIPSS (LSFL with a spatial period of Λ ∼ 260 nm and an orientation perpendicular to polarization) and High Spatial Frequency LIPSS (HSFL with a spatial period of Λ ∼ 130 nm and an orientation parallel to the polarization) were observed. The regime of regular spikes formation was determined for N ≥ 1000. Moreover, the 2D-map of the relationship among LIPSS formation, laser fluence and number of laser shots on copper thin film with two different substrates was established. A physics interpretation of regular spikes and LIPSS formation on copper thin film induced by ps laser with overlapping multi-shots is proposed based on experimental data and the theory of Plateau-Rayleigh instability.

  1. Picosecond laser induced periodic surface structure on copper thin films

    Science.gov (United States)

    Huynh, Thi Trang Dai; Petit, Agnès; Semmar, Nadjib

    2014-05-01

    LIPSS (Laser Induced Periodic Surface Structure) formation on copper thin films induced by a picosecond laser beam (Nd:YAG laser at 266 nm, 42 ps and 10 Hz) was studied experimentally. Copper thin films were deposited on glass and silicon substrates by magnetron sputtering. The surface modifications of irradiated zones were analyzed by scanning electron microscopy. Two distinct types of LIPSS were identified with respect to the laser fluence (F), number of laser shots (N) and substrate material. Namely, with a number of laser shots (1000 LIPSS (LSFL with a spatial period of Λ ∼ 260 nm and an orientation perpendicular to polarization) and High Spatial Frequency LIPSS (HSFL with a spatial period of Λ ∼ 130 nm and an orientation parallel to the polarization) were observed. The regime of regular spikes formation was determined for N ≥ 1000. Moreover, the 2D-map of the relationship among LIPSS formation, laser fluence and number of laser shots on copper thin film with two different substrates was established. A physics interpretation of regular spikes and LIPSS formation on copper thin film induced by ps laser with overlapping multi-shots is proposed based on experimental data and the theory of Plateau-Rayleigh instability.

  2. Biomimetic hairy surfaces as superhydrophobic highly transmissive films for optical applications (Conference Presentation)

    Science.gov (United States)

    Vuellers, Felix; Gomard, Guillaume; Preinfalk, Jan B.; Klampaftis, Efthymios; Worgull, Matthias; Richards, Bryce S.; Hölscher, Hendrik; Kavalenka, Maryna N.

    2017-02-01

    Combining high optical transmission, water-repellency and self-cleaning is of great interest for optoelectronic devices operating in outdoor conditions, such as photovoltaics where shading can significantly reduce the power output. The surface of water plant Pistia stratiotes combines these functionalities through a dense layer of transparent microhairs. It renders the surface superhydrophobic without affecting absorption of sunlight necessary for photosynthesis. Inspired by this surface, we fabricated a superhydrophobic flexible thin nanofur film made from optical grade polycarbonate using a scalable combination of hot embossing and hot pulling techniques. During fabrication, heated sandblasted steel plates locally elongate softened polymer, thus covering its surface in microcavities surrounded by high aspect ratio micro- and nanohairs. The superhydrophobic nanofur exhibits contact angles of (166+/-6°), low sliding angles (film stands above 85% over the visible range, with 97% of the transmitted light scattered forward. Reflection drops below 4% when coated on a polymeric substrate, which can enhance light extraction in organic light emitting diodes (OLEDs). We report an increase of more than 10% in luminous efficacy for a nanofur coated OLED compared to a bare device. Finally, the nanofur film can be used for enhancing the incoupling of light to solar cells, while additionally providing self-cleaning properties. Optical coupling of the nanofur to a multi-crystalline silicon solar cell results in a 5.8% gain in photocurrent compared to a bare device under normal incidence.

  3. Enhanced mechanical properties of low-surface energy thin films by simultaneous plasma polymerization of fluorine and epoxy containing polymers

    Energy Technology Data Exchange (ETDEWEB)

    Karaman, Mustafa, E-mail: karamanm@selcuk.edu.tr [Department of Chemical Engineering, Selçuk University, Konya, 42075 (Turkey); Advanced Technology Research & Application Center, Selçuk University, Konya, 42075 (Turkey); Uçar, Tuba [Department of Chemical Engineering, Selçuk University, Konya, 42075 (Turkey)

    2016-01-30

    Graphical abstract: - Highlights: • Thin films of poly(hexafluorobutyl acrylate-glycidyl methacrylate) can be deposited by PECVD. • The coated surfaces are hydrophobic due to the long fluorinated side chains. • The hydrophobicity of the coating is observed to be stable under harsh conditions. • Film durability is attributed to the mechanical strength of the films due to their epoxide functionality. - Abstract: Thin films of poly(2,2,3,4,4,4 hexafluorobutyl acrylate-glycidyl methacrylate) (P(HFBA-GMA) were deposited on different surfaces using an inductively coupled RF plasma reactor. Fluorinated polymer was used to impart hydrophobicity, whereas epoxy polymer was used for improved durability. The deposition at a low plasma power and temperature was suitable for the functionalization of fragile surfaces such as textile fabrics. The coated rough textile surfaces were found to be superhydrophobic with water contact angles greater than 150° due to the high retention of long fluorinated side chains. The hydrophobicity of the surfaces was observed to be stable after many exposures to ultrasonification tests, which is attributed to the mechanical durability of the films due to their epoxide functionality. FTIR and XPS analyses of the deposited films confirmed that the epoxide functionality of the polymers increased with increasing glycidyl methacrylate fraction in the reactor inlet. The modulus and hardness values of the films also increase with increasing epoxide functionality.

  4. Fabrication of transparent and conductive carbon nanotube/polyvinyl butyral films by a facile solution surface dip coating method

    Science.gov (United States)

    Li, Yuanqing; Yu, Ting; Pui, Tzesian; Chen, Peng; Zheng, Lianxi; Liao, Kin

    2011-06-01

    We present a simple solution surface dip coating method for fabricating transparent and conductive carbon nanotube/polyvinyl butyral (CNT/PVB) composite films. This fabrication process is simple to scale production and requires only ethanol and water as solvents, which is green and environment friendly.We present a simple solution surface dip coating method for fabricating transparent and conductive carbon nanotube/polyvinyl butyral (CNT/PVB) composite films. This fabrication process is simple to scale production and requires only ethanol and water as solvents, which is green and environment friendly. Electronic supplementary information (ESI) available: Experimental section. See DOI: 10.1039/c1nr10302d

  5. Surface Water Treatment Workshop Manual.

    Science.gov (United States)

    Ontario Ministry of the Environment, Toronto.

    This manual was developed for use at workshops designed to increase the knowledge of experienced water treatment plant operators. Each of the fourteen lessons in this document has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that topic. Areas covered in this manual include: basic water…

  6. Evidence for water structuring forces between surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, Christopher B [ORNL; Rau, Dr. Donald [National Institutes of Health

    2011-01-01

    Structured water on apposing surfaces can generate significant energies due to reorganization and displacement as the surfaces encounter each other. Force measurements on a multitude of biological structures using the osmotic stress technique have elucidated commonalities that point toward an underlying hydration force. In this review, the forces of two contrasting systems are considered in detail: highly charged DNA and nonpolar, uncharged hydroxypropyl cellulose. Conditions for both net repulsion and attraction, along with the measured exclusion of chemically different solutes from these macromolecular surfaces, are explored and demonstrate features consistent with a hydration force origin. Specifically, the observed interaction forces can be reduced to the effects of perturbing structured surface water.

  7. Photocatalytic property of titanium dioxide thin films deposited by radio frequency magnetron sputtering in argon and water vapour plasma

    Energy Technology Data Exchange (ETDEWEB)

    Sirghi, L., E-mail: lsirghi@uaic.ro [Department of Physics, Alexandru Ioan Cuza University, Blvd. Carol I, 11, Iasi, 700506 (Romania); Hatanaka, Y. [Research Institute of Electronics, Shizuoka University, 3-5-1, Johoku Naka-ku Hamamatsu, 432-8011 (Japan); Sakaguchi, K. [Faculty of Engineering, Aichi University of Technology, 50-2 Manori, Nishihazama, Gamagori, 443-0047 Aichi (Japan)

    2015-10-15

    Highlights: • TiOx thin films were deposited by radio frequency magnetron sputtering in Ar and Ar/H{sub 2}O plasma. • The deposited films contain OH groups in their bulk structure irrespective of the water content of the working gas. • The structure and photocatalytic activity of the deposited films were studied. - Abstract: The present work is investigating the photocatalytic activity of TiO{sub 2} thin films deposited by radiofrequency magnetron sputtering of a pure TiO{sub 2} target in Ar and Ar/H{sub 2}O (pressure ratio 40/3) plasmas. Optical absorption, structure, surface morphology and chemical structure of the deposited films were comparatively studied. The films were amorphous and included a large amount of hydroxyl groups (about 5% of oxygen atoms were bounded to hydrogen) irrespective of the intentional content of water in the deposition chamber. Incorporation of hydroxyl groups in the film deposited in pure Ar plasma is explained as contamination of the working gas with water molecules desorbed by plasma from the deposition chamber walls. However, intentional input of water vapour into the discharge chamber decreased the deposition speed and roughness of the deposited films. The good photocatalytic activity of the deposited films could be attributed hydroxyl groups in their structures.

  8. Dynamics of freely suspended lyotropic films. I. An inelastic light scattering study of thermal surface fluctuations

    Science.gov (United States)

    Young, Charles Y.; Clark, Noel A.

    1981-04-01

    We have studied the spectrum and intensity of light scattered by thermal surface displacement fluctuations on freely suspended lyotropic films. Films consisted of a liquid core and surface soap layers and were drawn from solution containing water, glycerol, NaCl, and the ionic surfactant hexadecyltrimethyl ammonium bromide (HTAB). Two modes were observed: a propagating undulation mode in which the film surfaces move together and a damped peristaltic mode having oppositely moving surface soap layers. Dispersion relations for these modes, obtained from the dependence of the scattered light intensity correlation function on film thickness h and wave vector k, confirm the macroscopic hydrodynamic description of film motion. In particular, the overdamped peristaltic mode is shown to involve Poiseuille flow of the fluid core with the flow velocity zero within 2 Å of the surfactant-solution interface, indicating no significant slip or rigid interfacial water layer. No evidence of dispersion in the effective viscosity of the fluid core h(k,w) over the range 0surface waves in fluids. The dynamic surface tension term s(k,w) for k˜106 cm-1 and w˜6×10 sec-1 was found to be the same as the static value within experimental error. Analysis of the total scattered intensity and of the peristaltic mode dynamics allows the determination of R(h), that part of the film pressure due to electrostatic repulsive and van der Waals attractive forces. The measured R(h) are well represented by the sum of a repulsive screened electrostatic interaction and an attractive van der Waals term. The screened electrostatic interaction is consistent with the concentration of NaCl used and the attractive part of R could be fitted equally well by the simple nonretarded van der Waals form for a uniform dielectric slab, or the Ninham

  9. Vaporization Studies from Slag Surfaces Using a Thin Film Technique

    Science.gov (United States)

    Seetharaman, Seshadri; Shyrokykh, Tetiana; Schröder, Christina; Scheller, Piotr R.

    2013-08-01

    The investigations of vanadium vaporization from CaO-SiO2-FeO-V2O5 thin film slags were conducted using the single hot thermocouple technique (SHTT) with air as the oxidizing atmosphere. The slag samples were analyzed after the experiments by SEM/EDX. The vanadium content was found to decrease as a function of time. The loss of vanadium from the slag film after 30 minutes of oxidation was approximately 18 pct and after 50 minutes, it was nearly 56 pct. The possible mechanism of vanadium loss would be the surface oxidation of vanadium oxide in the slag, VO x to V5+, followed by surface evaporation of V2O5, which has a high vapor pressure at the experimental temperature.

  10. Thin-film limit formalism applied to surface defect absorption.

    Science.gov (United States)

    Holovský, Jakub; Ballif, Christophe

    2014-12-15

    The thin-film limit is derived by a nonconventional approach and equations for transmittance, reflectance and absorptance are presented in highly versatile and accurate form. In the thin-film limit the optical properties do not depend on the absorption coefficient, thickness and refractive index individually, but only on their product. We show that this formalism is applicable to the problem of ultrathin defective layer e.g. on a top of a layer of amorphous silicon. We develop a new method of direct evaluation of the surface defective layer and the bulk defects. Applying this method to amorphous silicon on glass, we show that the surface defective layer differs from bulk amorphous silicon in terms of light soaking.

  11. Neutron reflectometry of soft films supported on electrified surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Quirk, A.I. [Univ. of Saskatchewan, Dept. of Chemistry, Saskatoon, Saskatchewan (Canada); Vezvaie, M. [Canadian Neutron Beam Centre, Chalk River, Ontario (Canada); Burgess, I.J., E-mail: ian.burgess@usask.ca [Univ. of Saskatchewan, Dept. of Chemistry, Saskatoon, Saskatchewan (Canada)

    2014-07-01

    The specular reflection of neutrons is a non-destructive, nuclear-based technique, sensitive to low atomic number elements, has a high penetration depth, and can distinguish between isotopes of the same element. This makes neutron reflectometry (NR) especially effective for the study of biological membranes, soft films and buried interfaces. Furthermore, commonly used NR substrates such as silicon and quartz single-crystals can be modified with thin metallic layers to form conductive supports allowing for the precise control of the electrical state of the interface. The coupling of NR with in-situ electrochemical control provides a powerful tool to study the composition of soft and/or buried interfaces under conditions that mimic, for example, transmembrane potentials or corrosion potentials. Here we report our recent efforts to perform in situ electrochemical NR studies and the previous experimental framework from which they were developed. The talk will address technical and infrastructure challenges but emphasize scientific highlights from our work with biomimetic phospholipid membranes. 'Isotopic variation has been applied to quantify the electroporation and distribution of water as a function of surface charge density in lipid bilayers. These studies have more recently been extended to study the location of redox-active ubiquinone (coenzyme Q{sub 10}) in biomimetic lipid bilayers as a function of potential and temperature. To probe the location of ubiquinone, a phospholipid bilayer was prepared on a gold coated solid substrate using a combination of Langmuir-Blodgett and vesicle fusion techniques. The combination of these two methods allowed for the composition of the inner and outer membrane leaflets to be varied. Preliminary results show sensitivity to the location of a small biologically relevant molecule. (author)

  12. Spatial resolution in thin film deposition on silicon surfaces by combining silylation and UV/ozonolysis

    Science.gov (United States)

    Guo, Lei; Zaera, Francisco

    2014-12-01

    A simple procedure has been developed for the processing of silicon wafers in order to facilitate the spatially resolved growth of thin solid films on their surfaces. Specifically, a combination of silylation and UV/ozonolysis was tested as a way to control the concentration of the surface hydroxo groups required for subsequent atomic layer deposition (ALD) of metals or oxides. Water contact angle measurements were used to evaluate the hydrophilicity/hydrophobicity of the surface, a proxy for OH surface coverage, and to optimize the UV/ozonolysis treatment. Silylation with hexamethyldisilazane, trichloro(octadecyl)silane, or trimethylchlorosilane was found to be an efficient way to block the hydroxo sites and to passivate the underlying surface, and UV/O3 treatments were shown to effectively remove the silylation layer and to regain the surface reactivity. Both O3 and 185 nm UV radiation were determined necessary for the removal of the silylation layer, and additional 254 nm radiation was found to enhance the process. Attenuated total reflection-infrared absorption spectroscopy was employed to assess the success of the silylation and UV/O3 removal steps, and atomic force microscopy data provided evidence for the retention of the original smoothness of the surface. Selective growth of HfO2 films via TDMAHf + H2O ALD was seen only on the UV/O3 treated surfaces; total inhibition of the deposition was observed on the untreated silylated surfaces (as determined by x-ray photoelectron spectroscopy and ellipsometry). Residual film growth was still detected on the latter if the ALD was carried out at high temperatures (250 °C), because the silylation layer deteriorates under such harsh conditions and forms surface defects that act as nucleation sites for the growth of oxide grains (as identified by electron microscopy and scanning electron microscopy). We believe that the silylation-UV/O3 procedure advanced here could be easily implemented for the patterning of surfaces

  13. Surface Chemistry of Nano-Structured Mixed Metal Oxide Films

    Science.gov (United States)

    2012-12-11

    Low Temperature Synthesis and Characterization of Nanocrystalline Titanium Carbide with Tunable Porous Architectures, Chemistry of Materials, (01...of the C–H bond to form carboxyl, both of which decompose via a COd 2 intermediate to evolve CO2 and H2. High surface area, porous titanium carbide films...characterization of nanocrystalline titanium carbide with tunable porous architectures” Chem. Mater. 22, 319-329 (2010). http://dx.doi.org/10.1021/cm902184m 3

  14. Robust surface states in epitaxial Bi(111) thin films

    Science.gov (United States)

    Zhu, Kai; Jin, Xiaofeng

    Bulk Bi a prototype semimetal with trivial electronic band topology. Unanticipatedly, we show the Altshuler-Aronov-Spivak and Aharonov-Bohm effects in epitaxial Bi(111) thin films. Meanwhile, we clearly identify the interaction of the top and bottom surface states via quantum tunneling by the electrical conductance and weak anti-localization measurements. These results have significantly enriched our understanding about the electronic structure of Bi, which might be helpful for clearing up some of its longstanding subtle issues.

  15. Surface structures of poly(methyl methacrylate) films influenced by chain entanglement in the corresponding film-formation solution.

    Science.gov (United States)

    Xu, Jianquan; Liu, Yingjun; He, Jinsheng; Zhang, Rongping; Zuo, Biao; Wang, Xinping

    2014-11-28

    The effects of the properties of casting solution on the surface structure of poly(methyl methacrylate) (PMMA) films were systematically investigated. It was observed that the hydrophobicity of PMMA films increased with increasing viscosity of the corresponding polymer solution regardless of the film-formation techniques that were utilized. The ratio of the C-H symmetric stretching vibrations of methylene groups (hydrophobic components, with a peak at 2910 cm(-1)) to those of the ester methyl groups (relative hydrophilic components, with a peak at 2955 cm(-1)) from sum frequency generation (SFG) vibrational spectra, A2910/A2955, was used as a parameter to evaluate the structure on the film surface, which was related to the surface wettability of the films. The results showed that A2910/A2955 of cast PMMA films increased linearly with ηsp(0.3) (ηsp, the specific viscosity of the casting solution), whereas that of the corresponding spin-coated films showed a linear relationship defined as ηsp(0.3)E(0.26), where E is the average number of entanglement points per molecule (E = Mw/Me). These results indicate that a relative equilibrium conformation on the PMMA film surface, adopted from the perspective of thermodynamics, was easily achieved during film formation, when the conformation of the polymer chains in the corresponding casting solution was close to that in the bulk. For the spin-coated films, the chain entanglement structure in the casting solution was a more important factor for the resulting film to reach a relative equilibrium state, since this structure was in favor of maintaining the pristine conformation in casting solution under centrifugal force during spin-coating. This work may help to enhance the fundamental understanding of the formation of the film surface structure from polymer solution to the resulting solid film, which will affect not only the corresponding surface properties, but also the dynamics of the resulting thin films.

  16. Total Phosphorus in Surface Water (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess phosphorus in surface water can result in eutrophication. TOTALPFuture is reported in kilograms/hectare/year. More information about these resources,...

  17. Surface processing using water cluster ion beams

    Science.gov (United States)

    Takaoka, Gikan H.; Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku

    2013-07-01

    Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO2, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate (PC) were irradiated by water cluster ion beams. The sputtered depth increased with increasing acceleration voltage, and the sputtering rate was much larger than that obtained using Ar monomer ion irradiation. The sputtering yield for PMMA was approximately 200 molecules per ion, at an acceleration voltage of 9 kV. X-ray photoelectron spectroscopy (XPS) measurements showed that high-rate sputtering for the PMMA surface can be ascribed to the surface erosion by the water cluster ion irradiation. Furthermore, the micropatterning was demonstrated on the PMMA substrate. Thus, the surface irradiation by water cluster ion beams exhibited a chemical reaction based on OH radicals, as well as excited hydrogen atoms, which resulted in a high sputtering rate and low irradiation damage of the substrate surfaces.

  18. Surface processing using water cluster ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Takaoka, Gikan H., E-mail: gtakaoka@kuee.kyoto-u.ac.jp [Photonics and Electronics Science and Engineering Center, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku [Photonics and Electronics Science and Engineering Center, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2013-07-15

    Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO{sub 2}, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate (PC) were irradiated by water cluster ion beams. The sputtered depth increased with increasing acceleration voltage, and the sputtering rate was much larger than that obtained using Ar monomer ion irradiation. The sputtering yield for PMMA was approximately 200 molecules per ion, at an acceleration voltage of 9 kV. X-ray photoelectron spectroscopy (XPS) measurements showed that high-rate sputtering for the PMMA surface can be ascribed to the surface erosion by the water cluster ion irradiation. Furthermore, the micropatterning was demonstrated on the PMMA substrate. Thus, the surface irradiation by water cluster ion beams exhibited a chemical reaction based on OH radicals, as well as excited hydrogen atoms, which resulted in a high sputtering rate and low irradiation damage of the substrate surfaces.

  19. Exit Creek Water Surface Survey, June 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of survey data from a longitudinal profile of water surface surveyed June 23-24, 2013 at Exit Creek, a stream draining Exit Glacier in Kenai...

  20. US Forest Service Surface Drinking Water Importance

    Data.gov (United States)

    US Forest Service, Department of Agriculture — A map service on the www depicting watershed indexes to help identify areas of interest for protecting surface drinking water quality. The dataset depicted in this...

  1. Total Nitrogen in Surface Water (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALNFuture is reported in kilograms/hectare/year. More information about these resources, including...

  2. Surface Waters Information Management System (SWIMS)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Surface Waters Information Management System (SWIMS) has been designed to meet multi-agency hydrologic database needs for Kansas. The SWIMS project was supported...

  3. Interplay between surface and surface resonance states on height selective stability of fcc Dy(111) film at nanoscale.

    Science.gov (United States)

    Liu, Xiaojie; Wang, Cai-Zhuang; Hupalo, Myron; Ho, Kai-Ming; Thiel, Patricia A; Tringides, Michael C

    2016-11-16

    Using first-principles calculations we show that face-centered cubic Dy(111) ultrathin films exhibit height selective stability. The origin of such height selection can be attributed to the interplay between the localized surface states and surface resonance states due to electron confinement effects. Such effect could be utilized to manipulate the film thickness at the atomic level to achieve desirable film properties or to control the growth of nanostructures on the thin film for various applications.

  4. Surface Acoustic Wave (SAW Resonators for Monitoring Conditioning Film Formation

    Directory of Open Access Journals (Sweden)

    Siegfried Hohmann

    2015-05-01

    Full Text Available We propose surface acoustic wave (SAW resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM sensor measurements, which confirmed the suitability of the SAW resonators for this application.

  5. Surface Acoustic Wave (SAW) Resonators for Monitoring Conditioning Film Formation.

    Science.gov (United States)

    Hohmann, Siegfried; Kögel, Svea; Brunner, Yvonne; Schmieg, Barbara; Ewald, Christina; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Länge, Kerstin

    2015-05-21

    We propose surface acoustic wave (SAW) resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA) and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM) sensor measurements, which confirmed the suitability of the SAW resonators for this application.

  6. Optical and water repellant properties of Ag/SnO2 bilayer thin films

    Directory of Open Access Journals (Sweden)

    Ravipati Praveena

    2016-02-01

    Full Text Available The optical and water repellant properties of single layer and bilayer films of Ag and SnO2 deposited on glass substrates by thermal evaporation have been reported. Ag/SnO2 bilayers were deposited in two sequences wherein the deposition of SnO2 layer was followed by Ag deposition and vice versa. X-ray diffraction studies show that the Ag films crystallize in the FCC structure and SnO2 is amorphous, while atomic force microscopy images indicate the formation of large clusters of the order of 12 nm. The single layer Ag films exhibit localized surface plasmon resonance (LSPR that shifts from visible region to the infrared with increase in thickness from 5 to 12 nm. It is observed that, only the Ag films of thickness ≤ 8 nm exhibits LSPR peak whereas the critical thickness is 5 nm for Ag/SnO2 films. A blue shift is observed in the LSPR peak position when the SnO2 layer caps the Ag film. Whereas, the LSPR of Ag is suppressed significantly when the SnO2 layer is introduced between the glass and the Ag film and also when Ag and SnO2 were co-evaporated. Water repellant properties indicate that the pure Ag film has an average contact angle of 104o which decreases to 100o when SnO2 caps the Ag layer and 97o when Ag is deposited on top of the SnO2 buffer layer. Co-evaporated Ag-SnO2 films show a contact angle of 93o.

  7. Atomic layer deposition of TiO2 on surface modified nanoporous low-k films.

    Science.gov (United States)

    Levrau, Elisabeth; Devloo-Casier, Kilian; Dendooven, Jolien; Ludwig, Karl F; Verdonck, Patrick; Meersschaut, Johan; Baklanov, Mikhail R; Detavernier, Christophe

    2013-10-01

    This paper explores the effects of different plasma treatments on low dielectric constant (low-k) materials and the consequences for the growth behavior of atomic layer deposition (ALD) on these modified substrates. An O2 and a He/H2 plasma treatment were performed on SiCOH low-k films to modify their chemical surface groups. Transmission FTIR and water contact angle (WCA) analysis showed that the O2 plasma changed the hydrophobic surface completely into a hydrophilic surface, while the He/H2 plasma changed it only partially. In a next step, in situ X-ray fluorescence (XRF), ellipsometric porosimetry (EP), and Rutherford backscattering spectroscopy (RBS) were used to characterize ALD growth of TiO2 on these substrates. The initial growth of TiO2 was found to be inhibited in the original low-k film containing only Si-CH3 surface groups, while immediate growth was observed in the hydrophilic O2 plasma treated film. The latter film was uniformly filled with TiO2 after 8 ALD cycles, while pore filling was delayed to 17 ALD cycles in the hydrophobic film. For the He/H2 plasma treated film, containing both Si-OH and Si-CH3 groups, the in situ XRF data showed that TiO2 could no longer be deposited in the He/H2 plasma treated film after 8 ALD cycles, while EP measurements revealed a remaining porosity. This can be explained by the faster deposition of TiO2 in the hydrophilic top part of the film than in the hydrophobic bulk which leaves the bulk porous, as confirmed by RBS depth profiling. The outcome of this research is not only of interest for the development of advanced interconnects in ULSI technology, but also demonstrates that ALD combined with RBS analysis is a handy approach to analyze the modifications induced by a plasma treatment on a nanoporous thin film.

  8. FILM-30: A Heat Transfer Properties Code for Water Coolant

    Energy Technology Data Exchange (ETDEWEB)

    MARSHALL, THERON D.

    2001-02-01

    A FORTRAN computer code has been written to calculate the heat transfer properties at the wetted perimeter of a coolant channel when provided the bulk water conditions. This computer code is titled FILM-30 and the code calculates its heat transfer properties by using the following correlations: (1) Sieder-Tate: forced convection, (2) Bergles-Rohsenow: onset to nucleate boiling, (3) Bergles-Rohsenow: partially developed nucleate boiling, (4) Araki: fully developed nucleate boiling, (5) Tong-75: critical heat flux (CHF), and (6) Marshall-98: transition boiling. FILM-30 produces output files that provide the heat flux and heat transfer coefficient at the wetted perimeter as a function of temperature. To validate FILM-30, the calculated heat transfer properties were used in finite element analyses to predict internal temperatures for a water-cooled copper mockup under one-sided heating from a rastered electron beam. These predicted temperatures were compared with the measured temperatures from the author's 1994 and 1998 heat transfer experiments. There was excellent agreement between the predicted and experimentally measured temperatures, which confirmed the accuracy of FILM-30 within the experimental range of the tests. FILM-30 can accurately predict the CHF and transition boiling regimes, which is an important advantage over current heat transfer codes. Consequently, FILM-30 is ideal for predicting heat transfer properties for applications that feature high heat fluxes produced by one-sided heating.

  9. The Dynamic Surface Tension of Water.

    Science.gov (United States)

    Hauner, Ines M; Deblais, Antoine; Beattie, James K; Kellay, Hamid; Bonn, Daniel

    2017-03-23

    The surface tension of water is an important parameter for many biological or industrial processes, and roughly a factor of 3 higher than that of nonpolar liquids such as oils, which is usually attributed to hydrogen bonding and dipolar interactions. Here we show by studying the formation of water drops that the surface tension of a freshly created water surface is even higher (∼90 mN m(-1)) than under equilibrium conditions (∼72 mN m(-1)) with a relaxation process occurring on a long time scale (∼1 ms). Dynamic adsorption effects of protons or hydroxides may be at the origin of this dynamic surface tension. However, changing the pH does not significantly change the dynamic surface tension. It also seems unlikely that hydrogen bonding or dipole orientation effects play any role at the relatively long time scale probed in the experiments.

  10. Water desorption from nanostructured graphite surfaces.

    Science.gov (United States)

    Clemens, Anna; Hellberg, Lars; Grönbeck, Henrik; Chakarov, Dinko

    2013-12-21

    Water interaction with nanostructured graphite surfaces is strongly dependent on the surface morphology. In this work, temperature programmed desorption (TPD) in combination with quadrupole mass spectrometry (QMS) has been used to study water ice desorption from a nanostructured graphite surface. This model surface was fabricated by hole-mask colloidal lithography (HCL) along with oxygen plasma etching and consists of a rough carbon surface covered by well defined structures of highly oriented pyrolytic graphite (HOPG). The results are compared with those from pristine HOPG and a rough (oxygen plasma etched) carbon surface without graphite nanostructures. The samples were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The TPD experiments were conducted for H2O coverages obtained after exposures between 0.2 and 55 langmuir (L) and reveal a complex desorption behaviour. The spectra from the nanostructured surface show additional, coverage dependent desorption peaks. They are assigned to water bound in two-dimensional (2D) and three-dimensional (3D) hydrogen-bonded networks, defect-bound water, and to water intercalated into the graphite structures. The intercalation is more pronounced for the nanostructured graphite surface in comparison to HOPG surfaces because of a higher concentration of intersheet openings. From the TPD spectra, the desorption energies for water bound in 2D and 3D (multilayer) networks were determined to be 0.32 ± 0.06 and 0.41 ± 0.03 eV per molecule, respectively. An upper limit for the desorption energy for defect-bound water was estimated to be 1 eV per molecule.

  11. Elastic Properties of Natural Sea Surface Films Incorporated with Solid Dust Particles: Model Baltic Sea Studies

    Directory of Open Access Journals (Sweden)

    Adriana Z. Mazurek

    2012-01-01

    Full Text Available Floating dust-originated solid particles at air-water interfaces will interact with one another and disturb the smoothness of such a composite surface affecting its dilational elasticity. To quantify the effect, surface pressure (Π versus film area (A isotherm, and stress-relaxation (Π-time measurements were performed for monoparticulate layers of the model hydrophobic material (of μm-diameter and differentiated hydrophobicity corresponding to the water contact angles (CA ranging from 60 to 140° deposited at surfaces of surfactant-containing original seawater and were studied with a Langmuir trough system. The composite surface dilational modulus predicted from the theoretical approach, in which natural dust load signatures (particle number flux, daily deposition rate, and diameter spectra originated from in situ field studies performed along Baltic Sea near-shore line stations, agreed well with the direct experimentally derived data. The presence of seawater surfactants affected wettability of the solid material which was evaluated with different CA techniques applicable to powdered samples. Surface energetics of the particle-subphase interactions was expressed in terms of the particle removal energy, contact cross-sectional areas, collapse energies, and so forth. The hydrophobic particles incorporation at a sea surface film structure increased the elasticity modulus by a factor K (1.29–1.58. The particle-covered seawater revealed a viscoelastic behavior with the characteristic relaxation times ranging from 2.6 to 68.5 sec.

  12. Polyfluorinated chemicals in European surface waters, ground- and drinking waters

    NARCIS (Netherlands)

    Eschauzier, C.; de Voogt, P.; Brauch, H.-J.; Lange, F.T.; Knepper, T.P.; Lange, F.T.

    2012-01-01

    Polyfluorinated chemicals (PFCs), especially short chain fluorinated alkyl sulfonates and carboxylates, are ubiquitously found in the environment. This chapter aims at giving an overview of PFC concentrations found in European surface, ground- and drinking waters and their behavior during convention

  13. Polyfluorinated chemicals in European surface waters, ground- and drinking waters

    NARCIS (Netherlands)

    Eschauzier, C.; de Voogt, P.; Brauch, H.-J.; Lange, F.T.; Knepper, T.P.; Lange, F.T.

    2012-01-01

    Polyfluorinated chemicals (PFCs), especially short chain fluorinated alkyl sulfonates and carboxylates, are ubiquitously found in the environment. This chapter aims at giving an overview of PFC concentrations found in European surface, ground- and drinking waters and their behavior during

  14. Pectin-blended anionic polysaccharide films for cationic contaminant sorption from water.

    Science.gov (United States)

    Li, Mei; Buschle-Diller, Gisela

    2017-08-01

    Substantial amounts of industrial, agricultural, medical and domestic water worldwide are polluted by different types of contaminants. Removing these contaminants from effluent by adsorbent materials made from abundant, inexpensive polysaccharides is a feasible and promising approach to deal with this problem. In the present study, pectin blended with four other types of anionic polysaccharides, including alginate, carrageenan, xylan and xanthan, were crosslinked with zinc acetate and formed into thin films. In addition, a negatively charged polyelectrolyte, poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA) was coated on the film surface with the goal of increasing the capture of cationic contaminants. The average film thickness was measured by a digital micrometer. Surface morphologies and element analysis were obtained by energy dispersive spectroscopy connected with scanning electron microscopy. The swelling ratio and the mechanical properties of the films were investigated in relationship to their composition and PSSMA coating. The sorption of model cationic pollutants clearly improved for coated films and showed to be predominantly based on the interaction of positively and negatively charged groups between film/coating and contaminants. Published by Elsevier B.V.

  15. Surface chemical studies of chemical vapour deposited diamond thin films

    CERN Document Server

    Proffitt, S

    2001-01-01

    could not easily be correlated to the bulk film properties. It is suggested that electron emission arises from the graphite component of graphite- diamond grain boundaries that are present in the nanocrystalline films. species. The adsorbed O and Cl species are more strongly bound to the K layer than they are to the diamond substrate, so thermal desorption of K from the K/CI/diamond or K/O/diamond surface results also in the simultaneous loss ofO and Cl. The phosphorus precursor trisdimethylaminophosphine (TDMAP) has a negligible reactive sticking probability on the clean diamond surface. This can be increased by thermal cracking of the gas phase precursor by a heated filament, resulting in non-activated adsorption to produce an adlayer containing a mixture of surface-bound ligands and phosphorus containing species. The ligands were readily lost upon heating, leaving P, some of which was lost from the surface at higher temperatures. Pre-hydrogenation of the diamond surface inhibited the uptake of cracked TDMA...

  16. Surface hydrophobic modification of cellulose membranes by plasma-assisted deposition of hydrocarbon films

    Directory of Open Access Journals (Sweden)

    Mudtorlep Nisoa

    2010-03-01

    Full Text Available Surface modification by plasma polymerization is an efficient method to change the surface properties of a membrane. Desirable functionality such as hydrophobicity or hydrophilicity can be obtained, depending on plasma chemistry of gas precursors and discharge conditions. In this work, RF magnetron plasma is produced using acetylene and nitrogen as precursor gases. Variations of RF power, particle flux, deposited time and pressure of the precursor gases have been made to observe coating effects on the cellulose membranes. When appropriated conditions are used, a thin brownish film of hydrocarbon was formed on the membrane, and the water contact angle increased from 35 to 130 degrees.

  17. Thin films of solid electrolytes and studies of their surface

    Science.gov (United States)

    Pan, Xiaoren; Gu, Zhi X.

    1991-11-01

    Much research work has been done on the materials of solid electrolytes and their applications. Solid electrolytes or fast ionic conductors are generally used in solid state batteries and solid state ionic devices. In the utilization of solid electrolytes, thin film forms have practical advantages. They will make the devices and batteries miniaturization which is particularly important for certain applications such as microelectronic devices, space programs, and integrated circuits of self-contained power. So preparation of thin films of solid electrolytes and studies of their surfaces are significant. There has been interest in the properties of amorphous ionic conductors, as glasses have acknowledged advantages over crystalline electrolytes, including physical isotropy, the absence of grain boundaries, and continuously-variable composition. Furthermore, many glasses based on silver halides have conductivities as high as 10 Scm-1 at room temperature. So we have chosen the quaternary system AgI-Ag2O-P2O5-B2O3 as the basic materials, prepared thin films, studied their properties, and constructed thin film electrolytic batteries.

  18. Reduction of the water wettability of cellulose film through controlled heterogeneous modification.

    Science.gov (United States)

    Li, Wei; Wu, Yuehan; Liang, Weiwei; Li, Bin; Liu, Shilin

    2014-04-23

    A facile method had been applied to introduce hydrophobic properties to cellulose materials by incorporation of polyurethane acrylate (PUA) prepolymers into the porous structured cellulose matrix through dip-coating; then, PUA prepolymers were cured around interconnected cellulose fibers under UV light, encapsulating a cellulose matrix with a hydrophobic polymer shell. The characterization of the composite films confirmed the success of the heterogeneous modification, and the chemical structure of the cellulose matrix was preserved. The composite films integrated the merits of cellulose and PUA resin, but the highly hydrophilic behavior of cellulose has been reduced. Contact angle measurements with water demonstrated that the composite films had obvious hydrophobic properties and an obvious reduction in the water uptake and the permeability toward water vapor gas at different relative humidity was also observed. The transmittance of the composite films at 550 nm was about 85%. The thermal and mechanical properties of the composite films were improved when compared with that of PUA resin. The obtained composite based on cellulose and UV curing technology was a good choice for the development of biomass materials with modified surface properties.

  19. Surface Treatment of Polypropylene Films Using Homogeneous DBD Plasma at Atmospheric Pressure in Air%Surface Treatment of Polypropylene Films Using Homogeneous DBD Plasma at Atmospheric Pressure in Air

    Institute of Scientific and Technical Information of China (English)

    FANG Zhi; CAI Ling-ling; LEI Xiao; QIU Yu-chang; Kuffel Edmund

    2011-01-01

    The homogeneous dielectric barrier discharge (DBD) in atmospheric air is most favorable for polymer sur- face modification due to the low cost of operation and the ability of ambient on-line continuous uniform processing. In this paper, polypropylene (PP) films are treated using a homogeneous DBD plasma in atmospheric air. The surface properties of PP films are studied using contact angle and surface energy measurement, scanning electron microscopy (SEM) and Fourier trailsformed infrared spectroscopy (FTIR), and the aging effect after treatment when the treated materials are exposed to open air is also studied, with the modification mechanism being discussed. It is demonstrated that non thermal plasmas generated by homogeneous DBD in atmospheric air is an effective way to enhance the surface properties of PP films. After the pIasma treatment, the surface of PP film is etched, and oxygen-containing polar groups are introduced into the surface. These two processes can induce a remarkable decrease in water contact angle and a remarkable increase in surface energy, and the surface properties of PP films are improved accordingly.

  20. Friction Behaviors of the Hot Filament Chemical Vapor Deposition Diamond Film under Ambient Air and Water Lubricating Conditions

    Institute of Scientific and Technical Information of China (English)

    SHEN Bin; SUN Fanghong

    2009-01-01

    The friction behavior of the hot filament chemical vapor deposition(HFCVD) diamond film plays a critical role on its applications in mechanical fields and largely depends on the environment. Studies on the tribological properties of HFCVD diamond films coated on Co-cemented tungsten carbide (WC-Co) substrates are rarely reported in available literatures, especially in the water lubricating conditions. In this paper, conventional microcrystalline diamond(MCD) and fine-grained diamond(FGD) films are deposited on WC-Co substrates and their friction properties are evaluated on a reciprocating ball-on-plate tribometer, where they are brought to slide against ball-bearing steel and copper balls in dry and water lubricating conditions. Scanning electron microscopy(SEM), atomic force microscopy(AFM), surface profilometer and Raman spectroscopy are adopted to characterize as-deposited diamond films;SEM and energy dispersive X-ray(EDX) are used to investigate the worn region on the surfaces of both counterface balls and diamond films. The research results show that the friction coefficient of HFCVD diamond films always starts with a high initial value, and then gradually transits to a relative stable state. For a given counterface and a sliding condition, the FGD film presents lower stable friction coefficients by 0.02-0.03 than MCD film. The transferred materials adhered on sliding interface are supposed to have predominate effect on the friction behaviors of HFCVD diamond films. Furthermore, the effect of water lubricating on reducing friction coefficient is significant. For a given counterpart, the stable friction coefficients of MCD or FGD films reduce by about 0.07-0.08 while sliding in the water lubricating condition, relative to in dry sliding condition. This study is beneficial for widespread applications of HFCVD diamond coated mechanical components and adopting water lubricating system, replacing of oil lubricating, in a variety of mechanical processing fields to

  1. Deformation in Thin Glassy Polymer Films from Surface towards Interior

    Science.gov (United States)

    Chowdhury, Mithun; de Silva, Johann P.; Cross, Graham L. W.

    Polymer thin glassy films occupy an important place in last two decades of condensed matter research, concerning its surprising surface mobility and spatially dependent structural relaxation. However, ranges of cleverly designed indirect measurements on confined polymer glassy films already probed its mechanical properties; it is still a challenging task to directly probe such small confined volume through conventional mechanical testing. We have designed confined layer compression testing with a precisely designed and aligned flat probe during nanoindentation, which was further accompanied with atomic force microscopy. Due to natural confinement from the surrounding material, we show that a state of `uniaxial strain' is created beneath the probe under small axial strains. By this methodology we are able to directly probe uniaxial flows under both anelastic and plastic conditions while doing controlled creep studies at different positions in the film starting from surface towards interior. Depending on the extent of deformation, we found ranges of effects, such as densification, anelastic yield, and plastic yield. Enhanced creep rate upon deformation supports the idea of `deformation induced mobility'. Work performed at Trinity College Dublin.

  2. Femtosecond laser surface structuring of molybdenum thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kotsedi, L., E-mail: Kotsedi@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Mthunzi, P. [Council for Scientific and Industrial Research (CSIR), Biophotonics Lab: National Laser Centre Pretoria, 0001 (South Africa); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Eaton, S.M. [Physics Department, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Itala (Italy); Sechoghela, P.; Mongwaketsi, N. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Ramponi, R. [Institute for Photonics and Nanotechnologies (IFN)–CNR, Piazza Leanardo Da Vinci, 32, 20133 Milano (Italy); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa)

    2015-10-30

    Highlights: • Color change of the molybdenum thin film from shinny to violet–yellowish color after laser irradiation at various laser powers. • Formation of the molybdenum dioxide coating after laser exposure, as confirmed by the X-ray diffraction spectrometry. • Selective solar absorbing nature of the laser exposed films. • Study of the binding energies is presented in this contribution using the XPS spectrometry. - Abstract: This contribution reports on the femtosecond surface structuring of molybdenum thin coatings deposited by electron beam evaporation onto Corning glass substrates. The 1-D type periodic grating lines created by such an ablation showed that the widths of the shallow grooves followed a logarithmic dependence with the laser energy incident on the molybdenum film. The electronic valence “x” of the created oxide surface layer MoO{sub x} was found to be incident laser power dependent via Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy and X-ray diffraction investigations. Such a photo-induced MoO{sub x}–Mo nanocomposite exhibited effective selective solar absorption in the UV–vis–IR spectral range.

  3. Fabrication of endothelial progenitor cell capture surface via DNA aptamer modifying dopamine/polyethyleneimine copolymer film

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin; Deng, Jinchuan; Yuan, Shuheng; Wang, Juan; Luo, Rifang; Chen, Si [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Jin, E-mail: jinxxwang@263.net [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); Huang, Nan [Key Lab. of Advanced Technology for Materials of Education Ministry, Southwest Jiaotong University, Chengdu 610031 (China); School of Material Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2016-11-15

    Highlights: • The dopamine/PEI film with controlled amine density was successfully prepared. • The DNA aptamer was assembled onto the film via electrostatic incorporation. • The A@DPfilmscanspecificallyandeffectivelycaptureEPCs. • The A@DP film can support the survival of ECs, control the hyperplasia of SMCs. • The dynamic/co-culture models are useful for studying cells competitive adhesion. - Abstract: Endothelial progenitor cells (EPCs) are mainly located in bone marrow and circulate, and play a crucial role in repairmen of injury endothelium. One of the most promising strategies of stents designs were considered to make in-situ endothelialization in vivo via EPC-capture biomolecules on a vascular graft to capture EPCs directly from circulatory blood. In this work, an EPC specific aptamer with a 34 bases single strand DNA sequence was conjugated onto the stent surface via dopamine/polyethyleneimine copolymer film as a platform and linker. The assembled density of DNA aptamer could be regulated by controlling dopamine percentage in this copolymer film. X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) and fluorescence test confirmed the successful immobilization of DNA aptamer. To confirm its biofunctionality and cytocompatibility, the capturing cells ability of the aptamer modified surface and the effects on the growth behavior of human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs) were investigated. The aptamer functionalized sample revealed a good EPC-capture ability, and had a cellular friendly feature for both EPC and EC growth, while not stimulated the hyperplasia of SMCs. And, the co-culture experiment of three types of cells confirmed the specificity capturing of EPCs to aptamer modified surface, rather than ECs and SMCs. These data suggested that this aptamer functionalized surface may have a large potentiality for the application of vascular grafts with targeted endothelialization.

  4. Anomalous water drop bouncing on a nanotextured surface by the Leidenfrost levitation

    Science.gov (United States)

    Lee, Doo Jin; Song, Young Seok

    2016-05-01

    We report an anomalous liquid drop bouncing phenomenon that is generated by the Leidenfrost levitation due to a vapor layer reducing energy dissipation during the collision. The Leidenfrost levitation of water drops on both a hydrophobic surface and nanotextured Cassie surface is investigated. When the water drop is positioned onto the hydrophobic surface, a superhydrophobic feature is observed by the levitation effect due to the vapor film, which results in a slow evaporation of the drop due to the low thermal conductivity of the vapor layer that inhibits heat transfer between the heated surface and the water drop. In contrast, for the nanotextured surface, the water drop can bounce off after impact on the surface when it overcomes gravitational and adhesion forces. The spontaneous water drop bouncing on the nanotextured surface is powered by the combination effect of the Leidenfrost levitation and the non-wetting Cassie state.

  5. Molecular assembly and organic film growth on complex intermetallic surfaces

    Science.gov (United States)

    Al-Mahboob, Abdullah; Sharma, Hem Raj; Sadowski, Jerzy T.; Ledieu, Julian; Fournée, Vincent; McGrath, Ronan

    We extensively studied the role of molecular symmetry and symmetry/structures of wide ranges of substrate-surfaces from non-periodic to periodic to quasi-crystalline in nucleation, growth and phase transition in films made of organic molecular materials. Recently, most interest in quasicrystals is due to the generalization of aperiodic ordering to several classes of systems. Compared to periodic materials, these provide a closer approximation to an isotropic first Brillouin zone, which is of great importance to the design of new functional materials. Here, we present results obtained from our ongoing study of interface mediated molecular assembly extended on complex intermetallic surfaces with specific examples of C60 and Zn-phthalocyanine on quasicrystalline and approximant surfaces. We employed in-situ real-time low-energy electron microscopy (LEEM) for investigation of the processes in assembly and film growth and post-growth STM study and DFT calculations to understand structural details and growth mechanism. Research were carried out in part at the Center for Functional Nanomaterials, Brookhaven National Lab, USA; partly at Institut Jean Lamour, Université de Lorraine, France; and partly at the Surface Science Research Centre, University of Liverpool, UK.

  6. Stable water layers on solid surfaces.

    Science.gov (United States)

    Hong, Ying-Jhan; Tai, Lin-Ai; Chen, Hung-Jen; Chang, Pin; Yang, Chung-Shi; Yew, Tri-Rung

    2016-02-17

    Liquid layers adhered to solid surfaces and that are in equilibrium with the vapor phase are common in printing, coating, and washing processes as well as in alveoli in lungs and in stomata in leaves. For such a liquid layer in equilibrium with the vapor it faces, it has been generally believed that, aside from liquid lumps, only a very thin layer of the liquid, i.e., with a thickness of only a few nanometers, is held onto the surface of the solid, and that this adhesion is due to van der Waals forces. A similar layer of water can remain on the surface of a wall of a microchannel after evaporation of bulk water creates a void in the channel, but the thickness of such a water layer has not yet been well characterized. Herein we showed such a water layer adhered to a microchannel wall to be 100 to 170 nm thick and stable against surface tension. The water layer thickness was measured using electron energy loss spectroscopy (EELS), and the water layer structure was characterized by using a quantitative nanoparticle counting technique. This thickness was found for channel gap heights ranging from 1 to 5 μm. Once formed, the water layers in the microchannel, when sealed, were stable for at least one week without any special care. Our results indicate that the water layer forms naturally and is closely associated only with the surface to which it adheres. Our study of naturally formed, stable water layers may shed light on topics from gas exchange in alveoli in biology to the post-wet-process control in the semiconductor industry. We anticipate our report to be a starting point for more detailed research and understanding of the microfluidics, mechanisms and applications of gas-liquid-solid systems.

  7. Highly Hydrophilic Thin-Film Composite Forward Osmosis Membranes Functionalized with Surface-Tailored Nanoparticles

    KAUST Repository

    Tiraferri, Alberto

    2012-09-26

    Thin-film composite polyamide membranes are state-of-the-art materials for membrane-based water purification and desalination processes, which require both high rejection of contaminants and high water permeabilities. However, these membranes are prone to fouling when processing natural waters and wastewaters, because of the inherent surface physicochemical properties of polyamides. The present work demonstrates the fabrication of forward osmosis polyamide membranes with optimized surface properties via facile and scalable functionalization with fine-tuned nanoparticles. Silica nanoparticles are coated with superhydrophilic ligands possessing functional groups that impart stability to the nanoparticles and bind irreversibly to the native carboxyl moieties on the membrane selective layer. The tightly tethered layer of nanoparticles tailors the surface chemistry of the novel composite membrane without altering the morphology or water/solute permeabilities of the membrane selective layer. Surface characterization and interfacial energy analysis confirm that highly hydrophilic and wettable membrane surfaces are successfully attained. Lower intermolecular adhesion forces are measured between the new membrane materials and model organic foulants, indicating the presence of a bound hydration layer at the polyamide membrane surface that creates a barrier for foulant adhesion. © 2012 American Chemical Society.

  8. Effect of Surface Modification on Microbiol Polyhydroxyalkanoate Films on Biocompatibility

    Institute of Scientific and Technical Information of China (English)

    杨霰霜; 赵锴; 陈金春; 夏彩虹; 陈国强

    2001-01-01

    The purpose of this study was to investigate in vitro biocompatibility of a new type of polymer, polyhydroxybutyrate-co-hexanoate (PHBHHx). The hydrophilicity and biocompatibility were studied with two kinds of enzymes, amylase BAN480L and lipase Novozym388. The degree of hydrophilicity was observed using contact angle measurements. In vitro biocompatibility evaluations were carried out by direct incubation of mouse fibroblast cell line L929 on the polyhydroxyalkanoate (PHA) films. The samples treated with BAN480L showed that the PHA biocompatibility increased while the hydrophilicity decreased. Relative to untreated samples, the number of cells on the Novozym388 modified PHBHHx significant decrease as the hydrophilicity also decreased. The results indicated that other surface characteristics besides hydrophilicity influence the biocompatibility of PHBHHx films.

  9. Visualization of Surface Acoustic Waves in Thin Liquid Films

    Science.gov (United States)

    Rambach, R. W.; Taiber, J.; Scheck, C. M. L.; Meyer, C.; Reboud, J.; Cooper, J. M.; Franke, T.

    2016-02-01

    We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect.

  10. Investigation of water films on fuel rods in boiling water reactors using neutron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lanthen, Jonas

    2006-09-15

    In a boiling water reactor, thin films of liquid water around the fuel rods play a very important role in cooling the fuel, and evaporation of the film can lead to fuel damage. If the thickness of the water film could be measured accurately the reactor operation could be both safer and more economical. In this thesis, the possibility to use neutron tomography, to study thin water films on fuel rods in an experimental nuclear fuel set-up, has been investigated. The main tool for this has been a computer simulation software. The simulations have shown that very thin water films, down to around 20 pm, can be seen on fuel rods in an experimental set-up using neutron tomography. The spatial resolution needed to obtain this result is around 300 pm. A suitable detector system for this kind of experiment would be plastic fiber scintillators combined with a CCD camera. As a neutron source it would be possible to use a D-D neutron generator, which generates neutrons with energies of 2.5 MeV. Using a neutron generator with a high enough neutron yield and a detector with high enough detection efficiency, a neutron tomography to measure thin water films should take no longer than 25 - 30 minutes.

  11. Surface modification of polyurethane films by plasma and ultraviolet light to improve haemocompatibility for artificial heart valves.

    Science.gov (United States)

    Alves, P; Cardoso, R; Correia, T R; Antunes, B P; Correia, I J; Ferreira, P

    2014-01-01

    Prosthetic cardiac valves implantation is a common procedure used to treat heart valve diseases. Although there are different prostheses already available in the market (either mechanical or bioprosthetic), their use presents several problems, specifically concerning thrombogenicity and structural failure. Recently, some progresses have been achieved in developing heart valves based on synthetic materials with special emphasis in polymers. Among them, polyurethanes are one of the most commonly used for the production of these devices. Herein, Elastollan(®)1180A50, a thermoplastic polyurethane (TPU), was used to formulate films whose surfaces were modified by grafting 2-hydroxyethylmethacrylate (HEMA) either by ultra-violet (UV) or by plasma treatment. All films were analyzed before and after grafting. X-ray photoelectron spectroscopy (XPS) measurements were used to evaluate TPU surfaces functionalization. HEMA grafting was confirmed by the increase of the hydroxyl (OH) groups' concentration at the surface of the films. Atomic force microscopy (AFM) analysis was done to evaluate the surface topography of the biomaterials. Results showed that the roughness of the surface decreased when HEMA was grafted, especially for plasma treated samples. After grafting the films' hydrophilicity was improved, as well as the polar component of the surface energy, by 15-30%. Hydrophobic recovery studies using milli Q water or PBS were also performed to characterize the stability of the modified surface, showing that the films maintained their surface properties along time. Furthermore, blood-contact tests were performed to evaluate haemolytic and thrombogenic potential. The results obtained for HEMA grafted surfaces, using plasma treatment, confirmed biomaterials biocompatibility and low thrombogenicity. Finally, the cytotoxicity and antibacterial activity of the materials was assessed through in vitro assays for both modified films. The obtained results showed enhanced

  12. Mechanical properties and solubility in water of corn starch-collagen composite films: Effect of starch type and concentrations.

    Science.gov (United States)

    Wang, Kun; Wang, Wenhang; Ye, Ran; Liu, Anjun; Xiao, Jingdong; Liu, Yaowei; Zhao, Yana

    2017-02-01

    This study investigated the possibility of enhancing the properties of collagen with three different maize starches: waxy maize starch, normal starch, and high amylose starch. Scanning electron microscopy images revealed that starch-collagen films had a rougher surface compared to pure collagen films which became smoother upon heating. Amylose starch and normal starch increased the tensile strength of unheated collagen films in both dry and wet states, while all starches increased tensile strength of collagen film by heating. Depending upon the amylose content and starch concentrations, film solubility in water decreased with the addition of starch. DSC thermograms demonstrated that addition of all starches improved the thermal stability of the collagen film. Moreover, X-ray diffraction results indicated that except for high amylose starch, the crystallinity of both starch and collagen was significantly decreased when subject to heating. FTIR spectra indicated that intermolecular interactions between starch and collagen were enhanced upon heating.

  13. Radiolysis of water with aluminum oxide surfaces

    Science.gov (United States)

    Reiff, Sarah C.; LaVerne, Jay A.

    2017-02-01

    Aluminum oxide, Al2O3, nanoparticles with water were irradiated with γ-rays and 5 MeV He ions followed by the determination of the production of molecular hydrogen, H2, and characterization of changes in the particle surface. Surface analysis techniques included: diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), nitrogen absorption with the Brunauer - Emmett - Teller (BET) methodology for surface area determination, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Production of H2 by γ-ray radiolysis was determined for samples with adsorbed water and for Al2O3 - water slurries. For Al2O3 samples with adsorbed water, the radiation chemical yield of H2 was measured as 80±20 molecules/100 eV (1 molecule/100 eV=1.04×10-7 mol/J). The yield of H2 was observed to decrease as the amount of water present in the Al2O3 - water slurries increased. Surface studies indicated that the α-phase Al2O3 samples changed phase following irradiation by He ions, and that the oxyhydroxide layer, present on the pristine sample, is removed by γ-ray and He ion irradiation.

  14. Water vapor interactions with polycrystalline titanium surfaces

    Science.gov (United States)

    Azoulay, A.; Shamir, N.; Volterra, V.; Mintz, M. H.

    1999-02-01

    The initial interactions of water vapor with polycrystalline titanium surfaces were studied at room temperature. Measurements of water vapor surface accumulation were performed in a combined surface analysis system incorporating direct recoils spectrometry (DRS), Auger electron spectroscopy and X-ray photoelectron spectroscopy. The kinetics of accommodation of the water dissociation fragments (H, O and OH) displayed a complex behavior depending not only on the exposure dose but also on the exposure pressure. For a given exposure dose the efficiency of chemisorption increased with increasing exposure pressure. DRS measurements indicated the occurrence of clustered hydroxyl moieties with tilted O-H bonds formed even at very low surface coverage. A model which assumes two parallel routes of chemisorption, by direct collisions (Langmuir type) and by a precursor state is proposed to account for the observed behavior. The oxidation efficiency of water seemed to be much lower than that of oxygen. No Ti 4+ states were detected even at high water exposure values. It is likely that hydroxyl species play an important role in the reduced oxidation efficiency of water.

  15. On the mechanics of thin films and growing surfaces

    KAUST Repository

    Holland, M. A.

    2013-05-24

    Many living structures are coated by thin films, which have distinct mechanical properties from the bulk. In particular, these thin layers may grow faster or slower than the inner core. Differential growth creates a balanced interplay between tension and compression and plays a critical role in enhancing structural rigidity. Typical examples with a compressive outer surface and a tensile inner core are the petioles of celery, caladium, or rhubarb. While plant physiologists have studied the impact of tissue tension on plant rigidity for more than a century, the fundamental theory of growing surfaces remains poorly understood. Here, we establish a theoretical and computational framework for continua with growing surfaces and demonstrate its application to classical phenomena in plant growth. To allow the surface to grow independently of the bulk, we equip it with its own potential energy and its own surface stress. We derive the governing equations for growing surfaces of zero thickness and obtain their spatial discretization using the finite-element method. To illustrate the features of our new surface growth model we simulate the effects of growth-induced longitudinal tissue tension in a stalk of rhubarb. Our results demonstrate that different growth rates create a mechanical environment of axial tissue tension and residual stress, which can be released by peeling off the outer layer. Our novel framework for continua with growing surfaces has immediate biomedical applications beyond these classical model problems in botany: it can be easily extended to model and predict surface growth in asthma, gastritis, obstructive sleep apnoea, brain development, and tumor invasion. Beyond biology and medicine, surface growth models are valuable tools for material scientists when designing functionalized surfaces with distinct user-defined properties. © The Author(s) 2013.

  16. Efficacy of AquatainTM, a monomolecular surface film, against the malaria vectors Anopheles stephensi and An. gambiae s.s. in the laboratory

    NARCIS (Netherlands)

    Bukhari, S.T.; Knols, B.G.J.

    2009-01-01

    Monomolecular films are used for mosquito control because of their asphyxiating effect on larvae and pupae. Compared with other films, Aquatain mosquito formulation (AMFTM) has an improved spreading ability and flexibility on a water surface. In the laboratory, AMFTM showed larvicidal, pupicidal, an

  17. A Water Rich Mars Surface Mission Scenario

    Science.gov (United States)

    Hoffman, Stephen; Andrews, Alida; Joosten, Kent; Watts, Kevin

    2017-01-01

    The surface of Mars once had abundant water flowing on its surface, but now there is a general perception that this surface is completely dry. Several lines of research have shown that there are sources of potentially large quantities of water at many locations on the surface, including regions considered as candidates for future human missions. Traditionally, system designs for these human missions are constrained to tightly recycle water and oxygen, and current resource utilization strategies involve ascent vehicle oxidizer production only. But the assumption of relatively abundant extant water may change this. Several scenarios were constructed to evaluate water requirements for human Mars expeditions to assess the impact to system design if locally produced water is available. Specifically, we have assessed water resources needed for 1) ascent vehicle oxidizer and fuel production, 2) open-loop water and oxygen life support requirements along with more robust usage scenarios, and 3) crew radiation protection augmentation. In this assessment, production techniques and the associated chemistry to transform Martian water and atmosphere into these useful commodities are identified, but production mass and power requirements are left to future analyses. The figure below illustrates the type of water need assessment performed and that will be discussed. There have been several sources of feedstock material discussed in recent literature that could be used to produce these quantities of water. This paper will focus on Mars surface features that resemble glacier-like forms on Earth. Several lines of evidence indicate that some of these features are in fact buried ice, likely remnants from an earlier ice age on Mars. This paper examines techniques and hardware systems used in the polar regions of Earth to access this buried ice and withdraw water from it. These techniques and systems will be described to illustrate options available. A technique known as a Rodriguez Well

  18. Understanding nanorheology and surface forces of confined thin films

    Science.gov (United States)

    Huang, Jun; Yan, Bin; Faghihnejad, Ali; Xu, Haolan; Zeng, Hongbo

    2014-02-01

    Understanding the nanorheology and associated intermolecular/surface forces of fluids in confined geometries or porous media is of both fundamental and practical importance, providing significant insights into various applications such as lubrication and micro/nanoelectromechanical systems. In this work, we briefly reviewed the fundamentals of nanoreheolgy, advances in experimental techniques and theoretical simulation methods, as well as important progress in the nanorheology of confined thin films. The advent of advanced experimental techniques such as surface forces apparatus (SFA), X-ray surface forces apparatus (XSFA) and atomic force microscope (AFM) and computational methods such as molecular dynamics simulations provides powerful tools to study a wide range of rheological phenomena at molecular level and nano scale. One of the most challenging issues unresolved is to elucidate the relationship between the rheological properties and structural evolution of the confined fluid films and particles suspensions. Some of the emerging research areas in the nanorheology field include, but are not limited to, the development of more advanced characterization techniques, design of multifunctional rheological fluids, bio-related nanorheology, and polymer brushes.

  19. Electrolysis of water on (oxidized) metal surfaces

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Logadottir, Ashildur; Nørskov, Jens Kehlet

    2005-01-01

    directly from the electronic structure calculations. We consider electrodes of Pt(111) and Au(111) in detail and then discuss trends for a series of different metals. We show that the difficult step in the water splitting process is the formation of superoxy-type (OOH) species on the surface...... by the splitting of a water molecule on top an adsorbed oxygen atom. One conclusion is that this is only possible on metal surfaces that are (partly) oxidized. We show that the binding energies of the different intermediates are linearly correlated for a number of metals. In a simple analysis, where the linear...... relations are assumed to be obeyed exactly, this leads to a universal relationship between the catalytic rate and the oxygen binding energy. Finally, we conclude that for systems obeying these relations, there is a limit to how good a water splitting catalyst an oxidized metal surface can become. (c) 2005...

  20. Biodegradable polyester films from renewable aleuritic acid: surface modifications induced by melt-polycondensation in air

    Science.gov (United States)

    Jesús Benítez, José; Alejandro Heredia-Guerrero, José; Inmaculada de Vargas-Parody, María; Cruz-Carrillo, Miguel Antonio; Morales-Flórez, Victor; de la Rosa-Fox, Nicolás; Heredia, Antonio

    2016-05-01

    Good water barrier properties and biocompatibility of long-chain biopolyesters like cutin and suberin have inspired the design of synthetic mimetic materials. Most of these biopolymers are made from esterified mid-chain functionalized ω-long chain hydroxyacids. Aleuritic (9,10,16-trihydroxypalmitic) acid is such a polyhydroxylated fatty acid and is also the major constituent of natural lac resin, a relatively abundant and renewable resource. Insoluble and thermostable films have been prepared from aleuritic acid by melt-condensation polymerization in air without catalysts, an easy and attractive procedure for large scale production. Intended to be used as a protective coating, the barrier's performance is expected to be conditioned by physical and chemical modifications induced by oxygen on the air-exposed side. Hence, the chemical composition, texture, mechanical behavior, hydrophobicity, chemical resistance and biodegradation of the film surface have been studied by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM), nanoindentation and water contact angle (WCA). It has been demonstrated that the occurrence of side oxidation reactions conditions the surface physical and chemical properties of these polyhydroxyester films. Additionally, the addition of palmitic acid to reduce the presence of hydrophilic free hydroxyl groups was found to have a strong influence on these parameters.

  1. Ozone Resistance, Water Permeability, and Concrete Adhesion of Metallic Films Sprayed on a Concrete Structure for Advanced Water Purification

    Directory of Open Access Journals (Sweden)

    Jin-Ho Park

    2017-03-01

    Full Text Available We evaluated the applicability of metal spray coating as a waterproofing/corrosion protection method for a concrete structure used for water purification. We carried out an ozone resistance test on four metal sprays and evaluated the water permeability and bond strength of the metals with superior ozone resistance, depending on the surface treatment method. In the ozone resistance test, four metal sprays and an existing ozone-proof paint were considered. In the experiment on the water permeability and bond strength depending on the surface treatment method, the methods of no treatment, surface polishing, and two types of pore sealing agents were considered. The results showed that the sprayed titanium had the best ozone resistance. Applying a pore sealing agent provided the best adhesion performance, of about 3.2 MPa. Applying a pore sealing agent also provided the best waterproofing performance. Scanning electron microscope analysis showed that applying a pore sealing agent resulted in an excellent waterproofing performance because a coating film formed on top of the metal spray coating. Thus, when using a metal spray as waterproofing/corrosion protection for a water treatment concrete structure, applying a pore sealing agent on top of a film formed by spraying titanium was concluded to be the most appropriate method.

  2. Inverse Gas Chromatography with Film Cell Unit: An Attractive Alternative Method to Characterize Surface Properties of Thin Films.

    Science.gov (United States)

    Klein, Géraldine L; Pierre, Guillaume; Bellon-Fontaine, Marie-Noëlle; Graber, Marianne

    2015-09-01

    Inverse gas chromatography (IGC) is widely used for the characterization of surfaces. The present work describes a novel IGC tool, the recently developed film cell module, which measures monolithic thin solid film surface properties, whereas only samples in powder or fiber state or polymer-coated supports can be studied by classic IGC. The surface energy of four different solid supports was measured using both classic IGC with columns packed with samples in the powder state, and IGC with the new film cell module or the sessile drop technique, using samples in the film state. The total surface energy and its dispersive and specific components were measured for glass, polyethylene, polyamide and polytetrafluoroethylene. Similar results were obtained for the four materials using the three different techniques. The main conclusion is that the new film cell module for IGC is an attractive alternative to the sessile drop technique as it gives very accurate and reproducible results for surface energy components, with significant savings in time and the possible control of sample humidity and temperature. This film cell module for IGC extends the application field of IGC to any thin solid film and can be used to study the effect of any surface treatment on surface energy.

  3. Surface Treatment of Polyethylene Terephthalate Film Using Atmospheric Pressure Glow Discharge in Air

    Institute of Scientific and Technical Information of China (English)

    方志; 邱毓昌; 王辉

    2004-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted.The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the surface oxygen content of PET surface increases to 39%, and the water contact angle decreases to 19°, respectively.

  4. Spontaneous cracking of amorphous solid water films and the dependence on microporous structure

    Science.gov (United States)

    Bu, Caixia; Dukes, Catherine A.; Baragiola, Raúl A.

    2016-11-01

    Vapor-deposited, porous, amorphous, water-ice films, also called amorphous solid water (ASW), crack spontaneously during growth when the film thickness exceeds a critical value (Lc). We measured the Lc during growth of ASW films as a function of growth temperature (Tg = 10 K, 30 K, and 50 K) and deposition angle (θ = 0°, 45°, and 55°) using a quartz crystal microbalance, an optical interferometer, and an infrared spectrometer. The critical thickness, 1-5 μm under our experimental conditions, increases with Tg and θ, an indication of film porosity. We suggest that ASW films undergo tensile stress due to the mismatch between substrate adhesion and contracting forces derived from the incompletely coordinated molecules on the surfaces of the pores. We provide a model to explain the observed dependences of Lc on the Tg and θ in the context of Griffith theory and estimate the tensile strength of low-temperature ASW to be ˜25-40 MPa. Our model can be applied more generally to describe fracture of other solids with microporous structures, such as metallic or ceramic materials with voids.

  5. The interaction of CsCl with films of solid water

    CERN Document Server

    Borodin, A; Krischok, S; Kempter, V

    2003-01-01

    The interaction of CsCl molecules with films of solid water (three layers thick, typically), deposited on a tungsten crystal at 130 K, was studied. Metastable impact electron spectroscopy (MIES) and UPS(HeI) were applied to study the emission from Cl3p and Cs5p and the highest occupied states 1b sub 1 , 3a sub 1 and 1b sub 2 of molecular water. Below a critical stoichiometry of about CsCl centre dot nH sub 2 O with n=6 the UPS spectra are quite similar to those from chlorides solvated in liquid water in as much as the relative positions and intensities of the water and salt features are concerned; very little emission from the ionization of Cl3p and Cs5p is observed with MIES. We conclude that the CsCl molecules become solvated in the water film. As long as n>6, the water spectrum remains characteristic for condensed water; at n6, water molecules not involved directly into the hydration of the salt molecules desorb around 140 K. Around 160 K all water has disappeared from the surface. Above this temperature o...

  6. Surface Modification of Water Purification Membranes.

    Science.gov (United States)

    Miller, Daniel J; Dreyer, Daniel R; Bielawski, Christopher W; Paul, Donald R; Freeman, Benny D

    2017-04-18

    Polymeric membranes are an energy-efficient means of purifying water, but they suffer from fouling during filtration. Modification of the membrane surface is one route to mitigating membrane fouling, as it helps to maintain high levels of water productivity. Here, a series of common techniques for modification of the membrane surface are reviewed, including surface coating, grafting, and various treatment techniques such as chemical treatment, UV irradiation, and plasma treatment. Historical background on membrane development and surface modification is also provided. Finally, polydopamine, an emerging material that can be easily deposited onto a wide variety of substrates, is discussed within the context of membrane modification. A brief summary of the chemistry of polydopamine, particularly as it may pertain to membrane development, is also described. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Surface Water Protection by Productive Buffers

    DEFF Research Database (Denmark)

    Christen, Benjamin

    Vegetated riparian buffer zones are a widely recommended best management practice in agriculture for protecting surface and coastal waters from diffuse nutrient pollution. On the background of the EU funded research project NitroEurope (NEU; www.NitroEurope.eu), this study concentrates...... on the mitigation of nitrogen pollution in surface and groundwater, using riparian buffer zones for biomass production. The objectives are to map suitable areas for buffer implementation across the six NEU study landscapes, model tentative N-loss mitigation, calculate biomass production potential and economic...... designed for local conditions could be a way of protecting water quality attractive to many stakeholders....

  8. Microscale investigation of thin film surface ageing of bitumen.

    Science.gov (United States)

    Das, P K; Kringos, N; Birgisson, B; Wallqvist, V

    2014-05-01

    This paper investigates the mechanism of bitumen surface ageing, which was validated utilizing the atomic force microscopy and the differential scanning calorimetry. To validate the surface ageing, three different types of bitumen with different natural wax content were conditioned in four different modes: both ultraviolet and air, only ultraviolet, only air and without any exposure, for 15 and 30 days. From the atomic force microscopy investigation after 15 and 30 days of conditioning period, it was found that regardless the bitumen type, the percentage of microstructure on the surface reduced with the degree of exposure and time. Comparing all the four different exposures, it was observed that ultraviolet radiation caused more surface ageing than the oxidation. It was also found that the combined effect was not simply a summation or multiplication of the individual effects. The differential scanning calorimetry investigation showed that the amount of crystalline fractions in bitumen remain constant even after the systematic conditioning. Interestingly, during the cooling cycle, crystallization of wax molecules started earlier for the exposed specimens than the without exposed one. The analysis of the obtained results indicated that the ageing created a thin film upon the exposed surface, which acts as a barrier and creates difficulty for the wax induced microstructures to float up at the surface. From the differential scanning calorimetry analysis, it can be concluded that the ageing product induced impurities in the bitumen matrix, which acts as a promoter in the crystallization process.

  9. Surface reactions of molecular and atomic oxygen with carbon phosphide films.

    Science.gov (United States)

    Gorham, Justin; Torres, Jessica; Wolfe, Glenn; d'Agostino, Alfred; Fairbrother, D Howard

    2005-11-01

    The surface reactions of atomic and molecular oxygen with carbon phosphide films have been studied using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Carbon phosphide films were produced by ion implantation of trimethylphosphine into polyethylene. Atmospheric oxidation of carbon phosphide films was dominated by phosphorus oxidation and generated a carbon-containing phosphate surface film. This oxidized surface layer acted as an effective diffusion barrier, limiting the depth of phosphorus oxidation within the carbon phosphide film to phosphorus atoms as well as the degree of phosphorus oxidation. For more prolonged AO exposures, a highly oxidized phosphate surface layer formed that appeared to be inert toward further AO-mediated erosion. By utilizing phosphorus-containing hydrocarbon thin films, the phosphorus oxides produced during exposure to AO were found to desorb at temperatures >500 K under vacuum conditions. Results from this study suggest that carbon phosphide films can be used as AO-resistant surface coatings on polymers.

  10. A constitutive-relationship model for film flow on rough fracture surfaces

    Science.gov (United States)

    Liu, H. H.

    Film flow on fracture surfaces may be an important mechanism for fast flow in unsaturated fractured rocks. Incorporating this mechanism into a numerical model requires knowledge of constitutive relationships for film flow. Based on fractal concepts and a conceptual argument of Tokunaga et al. that water films could be treated as analogues to water in unsaturated porous media, a simple constitutive-relationship model has been developed. The validity of the model is supported by excellent agreements between calculation results and experimental observations for two different fracture surfaces. L'écoulement en film sur les surfaces de fracture peut être un mécanisme important pour l'écoulement rapide dans les roches fracturées non saturées. L'incorporation de ce mécanisme dans un modèle numérique nécessite la connaissance des relations fondamentales pour l'écoulement en film. Basé sur des concepts fractals et sur un argument conceptuel de Tokunaga et al. selon lequel des films d'eau peuvent être considérés comme des analogues de l'eau en milieu poreux non saturé, un modèle simple des relations fondamentales a été développé. La validité de ce modèle est confirmée grâce à une excellente concordance entre les résultats du calcul et les observations expérimentales pour deux surfaces différentes de fractures. El flujo pelicular en la superficie de las fracturas puede ser un mecanismo importante para el flujo rápido en rocas fracturadas no saturadas. Incorporarlo en un modelo numérico requiere conocer las relaciones constitutivas del flujo pelicular. Se ha desarrollado un modelo de una relación constitutiva sencilla partiendo de conceptos fractales y de un argumento conceptual de Tokunaga et al., según el cual las películas de agua pueden ser tratadas como análogos del agua en medios porosos no saturados. La validez del modelo es corroborada por los excelentes ajustes entre los resultados numéricos y las observaciones experimentales en dos

  11. Surface-Water Conditions in Georgia, Water Year 2005

    Science.gov (United States)

    Painter, Jaime A.; Landers, Mark N.

    2007-01-01

    INTRODUCTION The U.S. Geological Survey (USGS) Georgia Water Science Center-in cooperation with Federal, State, and local agencies-collected surface-water streamflow, water-quality, and ecological data during the 2005 Water Year (October 1, 2004-September 30, 2005). These data were compiled into layers of an interactive ArcReaderTM published map document (pmf). ArcReaderTM is a product of Environmental Systems Research Institute, Inc (ESRI?). Datasets represented on the interactive map are * continuous daily mean streamflow * continuous daily mean water levels * continuous daily total precipitation * continuous daily water quality (water temperature, specific conductance dissolved oxygen, pH, and turbidity) * noncontinuous peak streamflow * miscellaneous streamflow measurements * lake or reservoir elevation * periodic surface-water quality * periodic ecological data * historical continuous daily mean streamflow discontinued prior to the 2005 water year The map interface provides the ability to identify a station in spatial reference to the political boundaries of the State of Georgia and other features-such as major streams, major roads, and other collection stations. Each station is hyperlinked to a station summary showing seasonal and annual stream characteristics for the current year and for the period of record. For continuous discharge stations, the station summary includes a one page graphical summary page containing five graphs, a station map, and a photograph of the station. The graphs provide a quick overview of the current and period-of-record hydrologic conditions of the station by providing a daily mean discharge graph for the water year, monthly statistics graph for the water year and period of record, an annual mean streamflow graph for the period of record, an annual minimum 7-day average streamflow graph for the period of record, and an annual peak streamflow graph for the period of record. Additionally, data can be accessed through the layer's link

  12. Ultra Water Repellent Polypropylene Surfaces with Tunable Water Adhesion.

    Science.gov (United States)

    Zhu, Tang; Cai, Chao; Guo, Jing; Wang, Rong; Zhao, Ning; Xu, Jian

    2017-03-22

    Polypropylene (PP), including isotactic PP (i-PP) and atactic PP (a-PP) with distinct tacticity, is one of the most widely used general plastics. Herein, ultra water repellent PP coatings with tunable adhesion to water were prepared via a simple casting method. The pure i-PP coating shows a hierarchical morphology with micro/nanobinary structures, exhibiting a water contact angle (CA) larger than 150° and a sliding angle less than 5° (for 5 μL water droplet). In contrast, the pure a-PP coating has a less rough morphology with a water contact angle of about 130°, and the water droplets stick on the coating at any tilted angles. For the composite i-PP/a-PP coatings, however, ultra water repellency with CA > 150° but water adhesion tailorable from slippery to sticky can be realized, depending on the contents of a-PP and i-PP. The different wetting behaviors are due to the various microstructures of the composite coatings resulting from the distinct crystallization ability of a-PP and i-PP. Furthermore, the existence of a-PP in the composite coatings enhances the mechanical properties compared to the i-PP coating. The proposed method is feasible to modify various substrates and potential applications in no-loss liquid transportation, slippery surfaces, and patterned superhydrophobic surfaces are demonstrated.

  13. Temperature programmed desorption and infrared spectroscopic studies of thin water films on MgO(1 0 0)

    Science.gov (United States)

    Hawkins, S.; Kumi, G.; Malyk, S.; Reisler, H.; Wittig, C.

    2005-03-01

    Thin water (D 2O) films on MgO(1 0 0) surfaces have been studied. Water was deposited at 115 K and monolayer and multilayer films were prepared by annealing above 150 K, where the transition from amorphous solid to cubic ice is known to take place, and then re-cooling. Temperature programmed desorption traces and transmission Fourier transform infrared spectra were recorded. For the monolayer, results are consistent with an essentially flat, hydrogen-bonded water network without a significant amount of dangling OD. Ice growing on the monolayer appears to be a blend of amorphous and crystalline solid at 115 K, becoming more crystalline when annealed.

  14. Aging of the nanosized photochromic WO3 films and the role of adsorbed water in the photochromism

    Science.gov (United States)

    Gavrilyuk, A. I.

    2016-02-01

    Here it has been reported on aging of the nanosized WO3 film, which is revealed is continuous reduction of the photochromic sensitivity over time. Water molecules physically adsorbed on the film surface from ambient air form donor-acceptor and hydrogen bonds, changing gradually the adsorption state to chemisorption which prevents an access of organic molecules that serve as hydrogen donors by the photochromism. The mechanism of the process has been investigated and discussed. The role of water in the photochromism has been highlighted. The difference in the efficiency for being of a hydrogen donor in the photochromic process between water and organic molecules is discussed.

  15. Influence of Cu–Ti thin film surface properties on antimicrobial activity and viability of living cells

    Energy Technology Data Exchange (ETDEWEB)

    Wojcieszak, Damian, E-mail: damian.wojcieszak@pwr.edu.pl [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Kaczmarek, Danuta [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Antosiak, Aleksandra [Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Rudolfa Weigla 12, 53-114 Wrocław (Poland); Mazur, Michal [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Rybak, Zbigniew; Rusak, Agnieszka; Osekowska, Malgorzata [Department for Experimental Surgery and Biomaterials Research, Wroclaw Medical University, Poniatowskiego 2, 50-326 Wroclaw (Poland); Poniedzialek, Agata [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Gamian, Andrzej; Szponar, Bogumila [Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Rudolfa Weigla 12, 53-114 Wrocław (Poland)

    2015-11-01

    The paper describes properties of thin-film coatings based on copper and titanium. Thin films were prepared by co-sputtering of Cu and Ti targets in argon plasma. Deposited coatings consist of 90 at.% of Cu and 10 at.% of Ti. Characterization of the film was made on the basis of investigations of microstructure and physicochemical properties of the surface. Methods such as scanning electron microscopy, x-ray microanalysis, x-ray diffraction, x-ray photoelectron spectroscopy, atomic force microscopy, optical profilometry and wettability measurements were used to assess the properties of deposited thin films. An impact of Cu–Ti coating on the growth of selected bacteria and viability of the living cells (line L929, NCTC clone 929) was described in relation to the structure, surface state and wettability of the film. It was found that as-deposited films were amorphous. However, in such surroundings the nanocrystalline grains of 10–15 nm and 25–35 nm size were present. High surface active area with a roughness of 8.9 nm, had an effect on receiving relatively high water contact angle value (74.1°). Such wettability may promote cell adhesion and result in an increase of the probability of copper ion transfer from the film surface into the cell. Thin films revealed bactericidal and fungicidal effects even in short term-contact. High activity of prepared films was directly related to high amount (ca. 51 %) of copper ions at 1+ state as x-ray photoelectron spectroscopy results have shown. - Graphical abstract: Bactericidal and fungicidal effects of time contact with surface of Cu–Ti thin films. - Highlights: • Antimicrobial activity and cytotoxic effect (viability of L929 cell line) of metallic Cu–Ti films • Thin films were prepared by co-sputtering of Cu and Ti. • As-deposited Cu–Ti films were amorphous and homogenous. • Bactericidal and fungicidal effects even in short term-contact were observed.

  16. Experimental investigation of nucleate boiling and thin-film evaporation on enhanced silicon surfaces

    Science.gov (United States)

    Malla, Shailesh

    The present work consists of two major studies. The first study investigates the effects of surface energy or wettability on nucleate pool boiling and the second study investigates the thin-film evaporative cooling for near junction thermal management. For the first study, effects of surface energy or wettability on critical heat flux (CHF) and boiling heat transfer (BHT) of smooth heated surfaces was studied in saturated pool boiling of water at 1 atm. For this purpose hydrophilic and hydrophobic surfaces were created on one side of 1cm x 1cm double-side polished silicon substrates. A resistive heating layer was applied on the opposite side of each substrate. The surface energies of the created surfaces were characterized by measuring the static contact angles of water sessile drops. To provide a wide range of surface energies, surfaces were made of Teflon (hydrophobic), bare silicon (hydrophilic) and aluminum oxide (most hydrophilic). The measured contact angles on these surfaces were ˜108, ˜57 and ˜13 degrees respectively. The results of pool boiling tests on these surfaces clearly illustrate the connection between surface energy and CHF. CHF was shown to linearly decrease with contact angle increase, from ˜125 W/cm2 on aluminum oxide (most hydrophilic) to nearly one tenth of this value on Teflon (hydrophobic). The most hydrophilic surface also produced increasingly better BHT than plain silicon and Teflon as heat flux increased. However, below ˜5 W/cm2 the hydrophobic surface demonstrated better heat transfer due to earlier onset of nucleate boiling, reducing surface superheats by up to ˜5 degrees relative to the other two surfaces. Above ˜5 W/cm2 the BHT of the hydrophobic surface rapidly deteriorated as superheat increased towards the value at CHF. To further understand the effect of surface energy on pool boiling performance, the growth and departure of bubbles from single nucleating sites on each surface were analyzed from high-speed video recordings

  17. Facile Growth of Porous Hematite Films for Photoelectrochemical Water Splitting

    Directory of Open Access Journals (Sweden)

    Shaohua Shen

    2013-01-01

    Full Text Available We introduced a simple fabrication method of porous hematite films with tunable thickness in an aqueous solution containing FeCl3 as the single precursor. We demonstrated that the optimized thickness was necessary for high performance photoelectrochemical water splitting, by balancing photon absorption and charge carrier transport. The highest photocurrent of ca. 0.15 mA cm−2 at 1.0 V versus Ag/AgCl was achieved on the 300 nm thick porous hematite film as photoanode, with IPCE at 370 nm and 0.65 V versus Ag/AgCl to be 9.0%. This simple method allows the facile fabrication of hematite films with porous nanostructure for enabling high photon harvesting efficiency and maximized interfacial charge transfer. These porous hematite films fabricated by this simple solution-based method could be easily modified by metal doping for further enhanced photoelectrochemical activity for water splitting.

  18. A new method for patterning azopolymer thin film surfaces

    Science.gov (United States)

    Sorkhabi, Sh. Golghasemi; Barille, R.; Ahmadi-Kandjani, S.; Zielinska, S.; Ortyl, E.

    2017-04-01

    We present a simple bottom-up approach via an incoherent unpolarized illumination and the choice of a solvent-droplet-induced-dewetting method to photoinduce nano doughnuts on the surface of azopolymer thin films. We demonstrate that doughnut-shaped nanostructures can be formed and tailored with a wide range of typical sizes, thus providing a rich field of applications using surface photo-patterning. Furthermore, due to the presence of highly photoactive azobenzene derivative in the material, illumination of these nanostructures by a polarized laser light shows the possibility of a further growth and reshaping opening the way for fundamental studies of size-dependent scaling laws of optical properties and possible fabrication of nano-reactor or nano-trap patterns.

  19. Ions Bombardment in Thin Films and Surface Processing

    Institute of Scientific and Technical Information of China (English)

    许沭华; 任兆杏

    2003-01-01

    Ions bombardment is very important in thin films and surface processing. The ionenergy and ion flux are two important parameters in ion bombardment. The ion current densitymainly dependent on the plasma density gives the number of energetic ions bombarding thesubstrate. The self-bias voltage in plasma sheath accelerates plasma ions towards the substrate.RF discharge can increase plasma density and RF bias can also provide the insulator substrate witha plasma sheath. In order to choose and control ion energy, ion density, the angle of incidence,and ion species, ion beam sources are used. New types of electrodeless ion sources (RF, MW,ECR-MW) have been introduced in detail. In the last, the effects of ion bombardment on thinfilms and surface processing are presented.

  20. Global modelling of Cryptosporidium in surface water

    Science.gov (United States)

    Vermeulen, Lucie; Hofstra, Nynke

    2016-04-01

    Introduction Waterborne pathogens that cause diarrhoea, such as Cryptosporidium, pose a health risk all over the world. In many regions quantitative information on pathogens in surface water is unavailable. Our main objective is to model Cryptosporidium concentrations in surface waters worldwide. We present the GloWPa-Crypto model and use the model in a scenario analysis. A first exploration of global Cryptosporidium emissions to surface waters has been published by Hofstra et al. (2013). Further work has focused on modelling emissions of Cryptosporidium and Rotavirus to surface waters from human sources (Vermeulen et al 2015, Kiulia et al 2015). A global waterborne pathogen model can provide valuable insights by (1) providing quantitative information on pathogen levels in data-sparse regions, (2) identifying pathogen hotspots, (3) enabling future projections under global change scenarios and (4) supporting decision making. Material and Methods GloWPa-Crypto runs on a monthly time step and represents conditions for approximately the year 2010. The spatial resolution is a 0.5 x 0.5 degree latitude x longitude grid for the world. We use livestock maps (http://livestock.geo-wiki.org/) combined with literature estimates to calculate spatially explicit livestock Cryptosporidium emissions. For human Cryptosporidium emissions, we use UN population estimates, the WHO/UNICEF JMP sanitation country data and literature estimates of wastewater treatment. We combine our emissions model with a river routing model and data from the VIC hydrological model (http://vic.readthedocs.org/en/master/) to calculate concentrations in surface water. Cryptosporidium survival during transport depends on UV radiation and water temperature. We explore pathogen emissions and concentrations in 2050 with the new Shared Socio-economic Pathways (SSPs) 1 and 3. These scenarios describe plausible future trends in demographics, economic development and the degree of global integration. Results and

  1. Determining Contact Angle and Surface Energy of Co60Fe20B20 Thin Films by Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    S. K. Wang

    2011-01-01

    Full Text Available This study examined the deposition of CoFeB thin films on a glass substrate at room temperature (RT, as well as the effects of conducting postannealing at heat annealing TA=150°C for 1 h. The thickness (tf of the CoFeB thin films ranged from 100 Å to 500 Å. The microstructure, average contact angle, and surface energy properties were also investigated. X-ray diffraction (XRD revealed that CoFeB films are nanocrystalline at RT and that post-annealing treatment increases in conjunction with the crystallinity. The surface energy of the CoFeB thin films is related to adhesive strength. The CoFeB films form a contact angle of larger than 90∘ with water as a test liquid. This finding demonstrates that the CoFeB film is hydrophobic. As tf increases from 100 Å to 500 Å, the surface energy at RT decreases from 40 mJ/mm2 to 32 mJ/mm2. During post-annealing treatment, the surface energy increases from 32 mJ/mm2 to 35 mJ/mm2, as tf increases from 100 Å to 300 Å; then it decreases to 31 mJ/mm2, as tf increases from 300 Å to 500 Å. The surface energy of the as-deposited CoFeB thin films exceeds that during post-annealing treatment at thicknesses of 100 Å and 200 Å, suggesting that as-deposited CoFeB thin film increases the adhesion.

  2. Superhydrophobic surfaces of the water bug Notonecta glauca: a model for friction reduction and air retention

    Directory of Open Access Journals (Sweden)

    Petra Ditsche-Kuru

    2011-03-01

    Full Text Available Superhydrophobic surfaces of plants and animals are of great interest for biomimetic applications. Whereas the self-cleaning properties of superhydrophobic surfaces have been extensively investigated, their ability to retain an air film while submerged under water has not, in the past, received much attention. Nevertheless, air retaining surfaces are of great economic and ecological interest because an air film can reduce friction of solid bodies sliding through the water. This opens perspectives for biomimetic applications such as low friction fluid transport or friction reduction on ship hulls. For such applications the durability of the air film is most important. While the air film on most superhydrophobic surfaces usually lasts no longer than a few days, a few semi-aquatic plants and insects are able to hold an air film over a longer time period. Currently, we found high air film persistence under hydrostatic conditions for the elytra of the backswimmer Notonecta glauca which we therefore have chosen for further investigations. In this study, we compare the micro- and nanostructure of selected body parts (sternites, upper side of elytra, underside of elytra in reference to their air retaining properties. Our investigations demonstrate outstanding air film persistence of the upper side of the elytra of Notonecta glauca under hydrostatic and hydrodynamic conditions. This hierarchically structured surface was able to hold a complete air film under hydrostatic conditions for longer than 130 days while on other body parts with simple structures the air film showed gaps (underside of elytra or even vanished completely after a few days (sternites. Moreover, the upper side of the elytra was able to keep an air film up to flow velocities of 5 m/s. Obviously the complex surface structure with tiny dense microtrichia and two types of larger specially shaped setae is relevant for this outstanding ability. Besides high air film persistence, the

  3. Reversible conversion of water-droplet mobility from rollable to pinned on a superhydrophobic functionalized carbon nanotube film.

    Science.gov (United States)

    Yang, Jin; Zhang, Zhaozhu; Men, Xuehu; Xu, Xianghui; Zhu, Xiaotao

    2010-06-01

    Poly(acrylic acid)-block-polystyrene (PAA-b-PS) functionalized multiwall carbon nanotubes (MWNTs) were prepared by nitroxide-mediated "living" free-radical polymerization. The product functionalized MWNTs (MWNT-PAA-b-PS) contained 20% by weight PAA-b-PS based on the infrared spectroscopy analysis and thermal gravimetric analysis. Such MWNT-PAA-b-PS nanoparticles can be used in spray coating method to fabricate superhydrophobic MWNT films, and water-droplet mobility on the superhydrophobic film can be reversibly converted from rollable to pinned through adjusting the appearance of PAA chains on the topmost surface of the film. Switching mechanism has been discussed in detail. We also directly observed the air-solid-liquid interface from the above of a water droplet by a microscope to confirm the superhydrophobic states, and proved that the transition between the wettability states appeared on the same surface with reversible conversion of water-droplet mobility.

  4. Theory for source-responsive and free-surface film modeling of unsaturated flow

    Science.gov (United States)

    Nimmo, J.R.

    2010-01-01

    A new model explicitly incorporates the possibility of rapid response, across significant distance, to substantial water input. It is useful for unsaturated flow processes that are not inherently diffusive, or that do not progress through a series of equilibrium states. The term source-responsive is used to mean that flow responds sensitively to changing conditions at the source of water input (e.g., rainfall, irrigation, or ponded infiltration). The domain of preferential flow can be conceptualized as laminar flow in free-surface films along the walls of pores. These films may be considered to have uniform thickness, as suggested by field evidence that preferential flow moves at an approximately uniform rate when generated by a continuous and ample water supply. An effective facial area per unit volume quantitatively characterizes the medium with respect to source-responsive flow. A flow-intensity factor dependent on conditions within the medium represents the amount of source-responsive flow at a given time and position. Laminar flow theory provides relations for the velocity and thickness of flowing source-responsive films. Combination with the Darcy-Buckingham law and the continuity equation leads to expressions for both fluxes and dynamic water contents. Where preferential flow is sometimes or always significant, the interactive combination of source-responsive and diffuse flow has the potential to improve prediction of unsaturated-zone fluxes in response to hydraulic inputs and the evolving distribution of soil moisture. Examples for which this approach is efficient and physically plausible include (i) rainstorm-generated rapid fluctuations of a deep water table and (ii) space- and time-dependent soil water content response to infiltration in a macroporous soil. ?? Soil Science Society of America.

  5. Ti-doped hematite thin films for efficient water splitting

    Science.gov (United States)

    Atabaev, Timur Sh.; Ajmal, Muhammad; Hong, Nguyen Hoa; Kim, Hyung-Kook; Hwang, Yoon-Hwae

    2015-03-01

    Uniform Ti-doped hematite thin films were deposited on transparent fluorine-doped tin oxide FTO coated glasses using a pulsed laser deposition method. An influence of dopant concentration on the photoelectrochemical characteristics was examined under water splitting. Photocurrent measurements indicated that 3 mol% of Ti atoms was optimal dopant concentration in hematite films produced by this method. The maximum photocurrent density of un-doped and 3 mol% Ti-doped Fe2O3 photoelectrodes was 0.67 and 1.64 mA/cm2 at 1.23 V versus RHE, respectively. The incorporation of Ti atoms into hematite photoelectrodes was found to drastically enhance the water splitting performance.

  6. Lithium content in potable water, surface water, ground water, and mineral water on the territory of Republic of Macedonia

    OpenAIRE

    Vesna Kostik; Biljana Bauer; Zoran Kavrakovski

    2014-01-01

    The aim of this study was to determine lithium concentration in potable water, surface water, ground, and mineral water on the territory of the Republic of Macedonia. Water samples were collected from water bodies such as multiple public water supply systems located in 13 cities, wells boreholes located in 12 areas, lakes and rivers located in three different areas. Determination of lithium concentration in potable water, surface water was performed by the technique of inductively coupl...

  7. Thermodynamic properties of water solvating biomolecular surfaces

    Science.gov (United States)

    Heyden, Matthias

    Changes in the potential energy and entropy of water molecules hydrating biomolecular interfaces play a significant role for biomolecular solubility and association. Free energy perturbation and thermodynamic integration methods allow calculations of free energy differences between two states from simulations. However, these methods are computationally demanding and do not provide insights into individual thermodynamic contributions, i.e. changes in the solvent energy or entropy. Here, we employ methods to spatially resolve distributions of hydration water thermodynamic properties in the vicinity of biomolecular surfaces. This allows direct insights into thermodynamic signatures of the hydration of hydrophobic and hydrophilic solvent accessible sites of proteins and small molecules and comparisons to ideal model surfaces. We correlate dynamic properties of hydration water molecules, i.e. translational and rotational mobility, to their thermodynamics. The latter can be used as a guide to extract thermodynamic information from experimental measurements of site-resolved water dynamics. Further, we study energy-entropy compensations of water at different hydration sites of biomolecular surfaces. This work is supported by the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft.

  8. Impinging Water Droplets on Inclined Glass Surfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Armijo, Kenneth Miguel; Lance, Blake; Ho, Clifford K.

    2017-09-01

    Multiphase computational models and tests of falling water droplets on inclined glass surfaces were developed to investigate the physics of impingement and potential of these droplets to self-clean glass surfaces for photovoltaic modules and heliostats. A multiphase volume-of-fluid model was developed in ANSYS Fluent to simulate the impinging droplets. The simulations considered different droplet sizes (1 mm and 3 mm), tilt angles (0deg, 10deg, and 45deg), droplet velocities (1 m/s and 3 m/s), and wetting characteristics (wetting=47deg contact angle and non-wetting = 93deg contact angle). Results showed that the spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) decreased with increasing inclination angle due to the reduced normal force on the surface. The hydrophilic surface yielded greater spread factors than the hydrophobic surface in all cases. With regard to impact forces, the greater surface tilt angles yielded lower normal forces, but higher shear forces. Experiments showed that the experimentally observed spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) was significantly larger than the simulated spread factor. Observed spread factors were on the order of 5 - 6 for droplet velocities of %7E3 m/s, whereas the simulated spread factors were on the order of 2. Droplets were observed to be mobile following impact only for the cases with 45deg tilt angle, which matched the simulations. An interesting phenomenon that was observed was that shortly after being released from the nozzle, the water droplet oscillated (like a trampoline) due to the "snapback" caused by the surface tension of the water droplet being released from the nozzle. This oscillation impacted the velocity immediately after the release. Future work should evaluate the impact of parameters such as tilt angle and surface wettability on the impact of particle/soiling uptake and removal to investigate ways that

  9. Surface-Controlled Orientational Transitions in Elastically Strained Films of Liquid Crystal That Are Triggered by Vapors of Toluene.

    Science.gov (United States)

    Bedolla Pantoja, Marco A; Abbott, Nicholas L

    2016-05-25

    We report the fabrication of chemically patterned microwells that enable the rapid and facile preparation (by spin coating and patterned dewetting) of thin films of liquid crystals (LCs) that have precise thicknesses (0.7-30 μm), are supported on chemically defined substrates, and have free upper surfaces. We use these microwells to prepare elastically strained nematic LC films supported on silica glass, gold, or polystyrene substrates and thereby characterize the response of the strained LC films to vapors of toluene. We report that low concentrations of toluene vapor (LC to lower the anchoring energy of the LC on these substrates, thus allowing the elastic energy of the strained LC film to drive the LC films through an orientational transition. The central role of the toluene-induced change in surface anchoring energy is supported by additional experiments in which the response of the nematic LC to changes in film thickness and substrate identity are quantified. A simple thermodynamic model captures these trends and yielded estimates of anchoring energies (8-22 μJ/m(2)). Significantly, the orientational transitions observed in these strained LC thin films occur at concentrations of toluene vapor that are almost 1 order of magnitude below those which lead to bulk phase transitions, and they are not triggered by exposure to water vapor. Overall, these results hint at principles for the design of responsive LC-based materials that can be triggered by concentrations of aromatic, volatile organic compounds that are relevant to human health.

  10. Top and bottom surfaces limit carrier lifetime in lead iodide perovskite films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ye; Yang, Mengjin; Moore, David T.; Yan, Yong; Miller, Elisa M.; Zhu, Kai; Beard, Matthew C.

    2017-01-23

    Carrier recombination at defects is detrimental to the performance of solar energy conversion systems, including solar cells and photoelectrochemical devices. Point defects are localized within the bulk crystal while extended defects occur at surfaces and grain boundaries. If not properly managed, surfaces can be a large source of carrier recombination. Separating surface carrier dynamics from bulk and/or grain-boundary recombination in thin films is challenging. Here, we employ transient reflection spectroscopy to measure the surface carrier dynamics in methylammonium lead iodide perovskite polycrystalline films. We find that surface recombination limits the total carrier lifetime in perovskite polycrystalline thin films, meaning that recombination inside grains and/or at grain boundaries is less important than top and bottom surface recombination. The surface recombination velocity in polycrystalline films is nearly an order of magnitude smaller than that in single crystals, possibly due to unintended surface passivation of the films during synthesis.

  11. Room-Temperature Growth of Al Films on Si(111)-7×7 Surface

    Institute of Scientific and Technical Information of China (English)

    LIU Hong; ZHANG Yan-Feng; WANG De-Yong; JIA Jin-Feng; XUE Qi-Kun

    2004-01-01

    @@ Reflection high energy electron diffraction and scanning tunnelling microscopy (STM) are used to investigate the structure and morphology of Al films deposited on Si(111)-7 × 7 surface at room temperature. The films are polycrystalline, made up of (100) and (111) oriented islands, which primarily result from the interface elastic effect and free surface energies of the Al (100) and (111) surfaces.

  12. Surface Modification of Polyimide Film by Dielectric Barrier Discharge at Atmospheric Pressure

    Science.gov (United States)

    Peng, Shi; Li, Lingjun; Li, Wei; Wang, Chaoliang; Guo, Ying; Shi, Jianjun; Zhang, Jing

    2016-04-01

    In this paper, polyimide (PI) films are modified using an atmospheric pressure plasma generated by a dielectric barrier discharge (DBD) in argon. Surface performance of PI film and its dependence on exposure time from 0 s to 300 s are investigated by dynamic water contact angle (WCA), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy in attenuated total multiple reflection mode (FTIR-ATR). The study demonstrates that dynamic WCA exhibits a minimum with 40 s plasma treatment, and evenly distributed nano-dots and shadow concaves appeared for 40 s and 12 s Ar plasma treatment individually. A short period of plasma modification can contribute to the scission of the imide ring and the introduction of C-O and C=O (-COOH) by detailed analysis of FTIR-ATR.

  13. Atomization off thin water films generated by high-frequency substrate wave vibrations.

    Science.gov (United States)

    Collins, David J; Manor, Ofer; Winkler, Andreas; Schmidt, Hagen; Friend, James R; Yeo, Leslie Y

    2012-11-01

    Generating aerosol droplets via the atomization of thin aqueous films with high frequency surface acoustic waves (SAWs) offers several advantages over existing nebulization methods, particularly for pulmonary drug delivery, offering droplet sizes in the 1-5-μm range ideal for effective pulmonary therapy. Nevertheless, the physics underlying SAW atomization is not well understood, especially in the context of thin liquid film formation and spreading and how this affects the aerosol production. Here, we demonstrate that the film geometry, governed primarily by the applied power and frequency of the SAW, indeed plays a crucial role in the atomization process and, in particular, the size of the atomized droplets. In contrast to the continuous spreading of low surface energy liquids atop similar platforms, high surface energy liquids such as water, in the present case, are found to undergo transient spreading due to the SAW to form a quasisteady film whose height is determined by self-selection of the energy minimum state associated with the acoustic resonance in the film and whose length arises from a competition between acoustic streaming and capillary effects. This is elucidated from a fundamental model for the thin film spreading behavior under SAW excitation, from which we show good agreement between the experimentally measured and theoretically predicted droplet dimension, both of which consistently indicate a linear relationship between the droplet diameter and the mechanical power coupled into the liquid by the SAW (the latter captured by an acoustic Weber number to the two thirds power, and the reciprocal of the SAW frequency).

  14. Analysis of polymer surfaces and thin-film coatings with Raman and surface enhanced Raman scattering

    CERN Document Server

    McAnally, G D

    2001-01-01

    This thesis investigates the potential of surface-enhanced Raman scattering (SERS) for the analysis and characterisation of polymer surfaces. The Raman and SERS spectra from a PET film are presented. The SERS spectra from the related polyester PBT and from the monomer DMT are identical to PET, showing that only the aromatic signals are enhanced. Evidence from other compounds is presented to show that loss of the carbonyl stretch (1725 cm sup - sup 1) from the spectra is due to a chemical interaction between the silver and surface carbonyl groups. The interaction of other polymer functional groups with silver is discussed. A comparison of Raman and SERS spectra collected from three faces of a single crystal shows the SERS spectra are depolarised. AFM images of the silver films used to obtain SERS are presented. They consist of regular islands of silver, fused together to form a complete film. The stability and reproducibility and of these surfaces is assessed. Band assignments for the SERS spectrum of PET are ...

  15. Using surface plasmon resonances to test the durability of silver copper films

    Science.gov (United States)

    Bussjager, Rebecca J.; MacLeod, H. Angus

    1996-09-01

    Silver has high reflectivity in the visible and infrared but cannot be used fully because of its distressing lack of durability. A technique that uses the surface plasmon resonance phenomenon offers a sensitive method for studying the corrosion of silver and assessing improvements. It has been used in the investigation of the effects of flashing a thin layer, approximately 1 nm thick, of copper over silver in an attempt at cathodic protection. Tests include exposing silver and silver-copper films to air, 94% relative humidity, water, and hydrogen sulfide.

  16. Water at surfaces with tunable surface chemistries and the chiral imprint of water around DNA

    Science.gov (United States)

    Petersen, Poul

    Aqueous interfaces are ubiquitous in atmospheric chemistry and biological systems but are notoriously hard to probe experimentally. Surface-specific vibrational spectroscopy offers an avenue to directly probe the vibrational modes of the water OH stretching band but this method is challenging to implement to buried surfaces. Here we present results from sum-frequency generation (SFG) spectroscopy probing the buried interface between a functionalized surface and aqueous solutions. Studying such buried surfaces offers the advantage of being able to systematically tune the surface chemistry using self-assembled monolayers, i.e. the hydrophobic and hydrophilic character, and examine the effect on the interfacial water. In addition to water at these controlled surfaces, we have initiated studying water at biological surfaces. This includes the solvation structure around DNA. X-ray experiments at cryogenic temperatures have found crystallographic water in the minor grove of DNA giving rise to the notion of a spine of hydration surrounding DNA. Such structured water should exhibit a chiral structure adapted from DNA. We investigate if such a chiral water structure exist around DNA at room temperature using chiral SFG. This work was supported by the National Science Foundation under a NSF CAREER Grant (CHE-1151079).

  17. Surface modification of copolymerized films from three-armed biodegradable macromers - An analytical platform for modified tissue engineering scaffolds.

    Science.gov (United States)

    Müller, Benno M; Loth, Rudi; Hoffmeister, Peter-Georg; Zühl, Friederike; Kalbitzer, Liv; Hacker, Michael C; Schulz-Siegmund, Michaela

    2017-03-15

    The concept of macromers allows for a broad adjustment of biomaterial properties by macromer chemistry or copolymerization. Copolymerization strategies can also be used to introduce reactive sites for subsequent surface modification. Control over surface features enables adjustment of cellular reactions with regard to site and object of implantation. We designed macromer-derived polymer films which function as non-implantable analytical substrates for the investigation of surface properties of equally composed scaffolds for bone tissue engineering. To this end, a toolbox of nine different biodegradable, three-armed macromers was thermally cross-copolymerized with poly(ethylene glycol)-methacrylate (PEG-MA) to films. Subsequent activation of PEG-hydroxyl groups with succinic anhydride and N-hydroxysuccinimid allowed for covalent surface modification. We quantified the capacity to immobilize analytes of low (amino-functionalized fluorescent dye, Fcad, and RGD-peptides) and high (alkaline phosphatase, ALP) molecular weight. Fcad grafting level was controlled by macromer chemistry, content and molecular weight of PEG-MA, but also the solvent used for film synthesis. Fcad molar amount per surface area was twentyfive times higher on high-swelling compared to low-swelling films, but differences became smaller when large ALP (appr. 2:1) were employed. Similarly, small differences were observed on RGD peptide functionalized films that were investigated by cell adhesion studies. Presentation of PEG-derivatives on surfaces was visualized by atomic force microscopy (AFM) which unraveled composition-dependent domain formation influencing fluorescent dye immobilization. Surface wetting characteristics were investigated via static water contact angle. We conclude that macromer ethoxylation and lactic acid content determined film swelling, PEG domain formation and eventually efficiency of surface decoration.

  18. The jet impact force of laser-induced bubble under the water-film with different thickness

    Science.gov (United States)

    Li, Beibei; Wang, Bingyang; Liu, Xiumei; He, Jie; Lu, Jian

    2015-05-01

    The effect of water-film on the laser-induced bubble was investigated by a piezoelectric ceramic transducer (PZT) sensor. Both of the collapse time and liquid-jet impact force of the bubble under the water-film were obtained, and the experiments were also completed in different laser energy. The collapse time increase with the thickness of the waterfilm, but the liquid-jet impact force decrease. We consider that the collapse time was affected by both of the rigid boundary and surface, and the increasing of the collapse time is the reason the decreasing of the liquid-jet impact force. The velocity of bubble wall is lower with the longer collapse time for the uniform bubbles energy, so the liquid-jet impact force is lower. For the other reasons, more laser energy would be absorbed by the thicker water-film, but the water was also splashed for the thinner water-film. So, for the thinner water-film, the bubble energy is higher, the liquidjet impact force is higher, but the maximal radius is smaller because of the splash process. In the other hand, both of the collapse time and the liquid-jet impact force are increase with the laser energy. These researches are useful for the laser processing under water.

  19. A Water Rich Mars Surface Mission Scenario

    Science.gov (United States)

    Hoffman, Stephen J.; Andrews, Alida; Joosten, B. Kent; Watts, Kevin

    2017-01-01

    In an on-going effort to make human Mars missions more affordable and sustainable, NASA continues to investigate the innovative leveraging of technological advances in conjunction with the use of accessible Martian resources directly applicable to these missions. One of the resources with the broadest utility for human missions is water. Many past studies of human Mars missions assumed a complete lack of water derivable from local sources. However, recent advances in our understanding of the Martian environment provides growing evidence that Mars may be more "water rich" than previously suspected. This is based on data indicating that substantial quantities of water are mixed with surface regolith, bound in minerals located at or near the surface, and buried in large glacier-like forms. This paper describes an assessment of what could be done in a "water rich" human Mars mission scenario. A description of what is meant by "water rich" in this context is provided, including a quantification of the water that would be used by crews in this scenario. The different types of potential feedstock that could be used to generate these quantities of water are described, drawing on the most recently available assessments of data being returned from Mars. This paper specifically focuses on sources that appear to be buried quantities of water ice. (An assessment of other potential feedstock materials is documented in another paper.) Technologies and processes currently used in terrestrial Polar Regions are reviewed. One process with a long history of use on Earth and with potential application on Mars - the Rodriguez Well - is described and results of an analysis simulating the performance of such a well on Mars are presented. These results indicate that a Rodriguez Well capable of producing the quantities of water identified for a "water rich" human mission are within the capabilities assumed to be available on the Martian surface, as envisioned in other comparable Evolvable

  20. Low-Flow Film Boiling Heat Transfer on Vertical Surfaces

    DEFF Research Database (Denmark)

    Munthe Andersen, J. G.; Dix, G. E.; Leonard, J. E.

    1976-01-01

    The phenomenon of film boiling heat transfer for high wall temperatures has been investigated. Based on the assumption of laminar flow for the film, the continuity, momentum, and energy equations for the vapor film are solved and a Bromley-type analytical expression for the heat transfer...... length, an average film boiling heat transfer coefficient is obtained....

  1. Spreading of oil on water in the surface-tension regime

    Energy Technology Data Exchange (ETDEWEB)

    Camp, D.W.; Berg, J.C.

    1987-11-01

    Data which describe the unidirectional spreading of several pure oils and oil-surfactant mixtures on water in the surface-tension regime are reported. Leading-edge position and profiles of velocity, thickness and film tension are given as functions of time. The data are consistent with the numerical similarity solution of Foda and Cox (1980), although the measured dependence of the film tension on the film thickness often differs from the equilibrium relationship. The configuration of the oil film near the spreading origin may be either a coherent multimolecular layer or a multitude of thinning, outward-moving lenses surrounded by monolayer. The pure oils show an acceleration zone connecting the slow-moving inner region to a fast-moving outer region, while the oil-surfactant mixtures show a much more gradual increase in film velocity.

  2. Atmospheric Pressure non-thermal plasmas for surface treatment of polymer films

    Science.gov (United States)

    Huang, Hsiao-Feng; Wen, Chun-Hsiang; Wei, Hsiao-Kuan; Kou, Chwung-Shan

    2006-10-01

    Interest has grown over the past few years in applying atmospheric pressure non-thermal plasmas to surface treatment. In this work, we used an asymmetric glow dielectric-barrier discharge (GDBD), at atmospheric pressure in nitrogen, to improve the surface hydrophilicity of three kinds of polymer films, biaxially oriented polypropylene (BOPP), polyimide (PI), and triacetyl cellulose (TAC). This set-up consists of two asymmetric electrodes covered by dielectrics. And to prevent the filamentary discharge occur, the frequency, gas flow rate and uniformity of gas flow distribution should be carefully controlled. The discharge performance is monitored through an oscilloscope, which is connected to a high voltage probe and a current monitor. The physical and chemical properties of polymer surfaces before and after GDBD treatment were analyzed via water contact angle (CA) measurements, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques.

  3. Modification of the hydrophilic/hydrophobic characteristic of zein film surfaces by contact with oxygen plasma treated PDMS and oleic acid content.

    Science.gov (United States)

    Gezer, P Gizem; Brodsky, Serena; Hsiao, Austin; Liu, G Logan; Kokini, Jozef L

    2015-11-01

    Zein has been widely studied as a biopolymer due to its unique film-forming abilities. Surface properties are of high importance for certain applications which include microfluidics and tissue engineering, as they drastically affect the end result. It is important to develop techniques to modify zein surface properties without compromising bulk material properties. In this study, we developed a facile technique to change the water affinity of zein film surfaces, compatible with patterning techniques via soft lithography. This is achieved by a simple solvent casting technique onto a polydimethylsilohexane (PDMS) substrate that was exposed to oxygen plasma. Water contact angle measurements (WCA) were used to assess the hydrophillicity of zein surfaces and they reached as low as 20°. Atomic force microscopy, optical absorbance and light microscopy were used to study the characteristics of the film and its surface topography. Hydrophilic zein surfaces had higher roughness values compared to hydrophobic ones. Surface roughness, introduced by sandpaper and gratings does not have the same effect as surface chemistry. The amphiphilic nature of plasticizer oleic acid also contributed to the change in the water contact angle of the films. In conclusion, we demonstrated that zein film's surface properties can be controlled by its ability to self-assemble depending on the substrate that it is being cast on.

  4. Streamers sliding on a water surface

    Science.gov (United States)

    Akishev, Yuri Semenov; Karalnik, Vladimir; Medvedev, Mikhail; Petryakov, Alexander; Trushkin, Nikolay; Shafikov, Airat

    2017-06-01

    The features of an electrical interaction between surface streamers (thin current filaments) sliding on a liquid and liquid itself are still unknown in many details. This paper presents the experimental results on properties of the surface streamers sliding on water with different conductivity (distilled and tap water). The streamers were initiated with a sharpened thin metallic needle placed above the liquid and stressed with a periodical or pulsed high voltage. Two electrode systems were used and tested. The first of them provides in advance the existence of the longitudinal electric field above the water. The second one imitates the electrode geometry of a pin-to-plane dielectric barrier discharge in which the barrier is a thick layer of liquid. The electrical and optical characteristics of streamers were complemented with data on the spectroscopic measurements. It was revealed that surface streamers on water have no spatial memory. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  5. Surface analysis of the selective excimer laser patterning of a thin PEDOT:PSS film on flexible polymer films

    Science.gov (United States)

    Schaubroeck, David; De Smet, Jelle; Willems, Wouter; Cools, Pieter; De Geyter, Nathalie; Morent, Rino; De Smet, Herbert; Van Steenbeerge, Geert

    2016-07-01

    Fast patterning of highly conductive polymers like PEDOT:PSS (poly (3,4-ethylene dioxythiophene): polystyrene sulfonate) with lasers can contribute to the development of industrial production of liquid crystal displays on polymer foils. In this article, the selective UV laser patterning of a PEDOT:PSS film on flexible polymer films is investigated. Based on their optical properties, three polymer films are investigated: polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and cellulose triacetate (TAC). Ablation parameters for a 110 nm PEDOT:PSS film on these polymer films are optimized. A detailed study of the crater depth, topography and surface composition are provided using optical profilometry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The electrical insulation of the lines is measured and correlated to the crater analyses for different laser settings. Finally, potential ablation parameters for each of the polymer films are derived.

  6. Uncertainty in surface water flood risk modelling

    Science.gov (United States)

    Butler, J. B.; Martin, D. N.; Roberts, E.; Domuah, R.

    2009-04-01

    Two thirds of the flooding that occurred in the UK during summer 2007 was as a result of surface water (otherwise known as ‘pluvial') rather than river or coastal flooding. In response, the Environment Agency and Interim Pitt Reviews have highlighted the need for surface water risk mapping and warning tools to identify, and prepare for, flooding induced by heavy rainfall events. This need is compounded by the likely increase in rainfall intensities due to climate change. The Association of British Insurers has called for the Environment Agency to commission nationwide flood risk maps showing the relative risk of flooding from all sources. At the wider European scale, the recently-published EC Directive on the assessment and management of flood risks will require Member States to evaluate, map and model flood risk from a variety of sources. As such, there is now a clear and immediate requirement for the development of techniques for assessing and managing surface water flood risk across large areas. This paper describes an approach for integrating rainfall, drainage network and high-resolution topographic data using Flowroute™, a high-resolution flood mapping and modelling platform, to produce deterministic surface water flood risk maps. Information is provided from UK case studies to enable assessment and validation of modelled results using historical flood information and insurance claims data. Flowroute was co-developed with flood scientists at Cambridge University specifically to simulate river dynamics and floodplain inundation in complex, congested urban areas in a highly computationally efficient manner. It utilises high-resolution topographic information to route flows around individual buildings so as to enable the prediction of flood depths, extents, durations and velocities. As such, the model forms an ideal platform for the development of surface water flood risk modelling and mapping capabilities. The 2-dimensional component of Flowroute employs

  7. RF Magnetron Sputtering Aluminum Oxide Film for Surface Passivation on Crystalline Silicon Wafers

    Directory of Open Access Journals (Sweden)

    Siming Chen

    2013-01-01

    Full Text Available Aluminum oxide films were deposited on crystalline silicon substrates by reactive RF magnetron sputtering. The influences of the deposition parameters on the surface passivation, surface damage, optical properties, and composition of the films have been investigated. It is found that proper sputtering power and uniform magnetic field reduced the surface damage from the high-energy ion bombardment to the silicon wafers during the process and consequently decreased the interface trap density, resulting in the good surface passivation; relatively high refractive index of aluminum oxide film is benefic to improve the surface passivation. The negative-charged aluminum oxide film was then successfully prepared. The surface passivation performance was further improved after postannealing by formation of an SiOx interfacial layer. It is demonstrated that the reactive sputtering is an effective technique of fabricating aluminum oxide surface passivation film for low-cost high-efficiency crystalline silicon solar cells.

  8. THE SURFACE EFFECT ON THE TENSILE STRENGTH OF MICROMACHINED POLYSILICON FILMS FOR MEMS

    Institute of Scientific and Technical Information of China (English)

    Ding Jianning; Yang Jichang; Wen Shizhu

    2005-01-01

    In order to accomplish reliable mechanical design of MEMS, the influences of surface roughness and octadecyltrichlorosilane (OTS) self-assembled monolayers (SAMs) on the mechanical properties of micromachined polysilicon films for MEMS are investigated. Surface effect on the fracture properties of micromachined polysilicon films is evaluated with a new microtensile testing method using a magnet-coil force actuator. Statistical analysis of the surface roughness effects on the tensile strength predicated the surface roughness characterization of polysilicon films being tested and the direct relation of the mechanical properties with the surface roughness features. The fracture strength decreases with the increase of the surface roughness. The octadecyltrichlorosilane self-assembled monolayers coating leads to an increase of the average fracture strength up to 32.46%. Surface roughness and the hydrophobic properties of specimen when coated with OTS films are the two main factors influencing the tensile strength of micromachined polysilicon films for MEMS.

  9. UV-Surface Treatment of Fungal Resistant Polyether Polyurethane Film-Induced Growth of Entomopathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Gabriela Albara Lando

    2017-07-01

    Full Text Available Synthetic polymers are the cause of some major environmental impacts due to their low degradation rates. Polyurethanes (PU are widely used synthetic polymers, and their growing use in industry has produced an increase in plastic waste. A commercial polyether-based thermoplastic PU with hydrolytic stability and fungus resistance was only attacked by an entomopathogenic fungus, Metarhiziumanisopliae, when the films were pre-treated with Ultraviolet (UV irradiation in the presence of reactive atmospheres. Water contact angle, Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR, scanning electron microscopy (SEM, and profilometer measurements were mainly used for analysis. Permanent hydrophilic PU films were produced by the UV-assisted treatments. Pristine polyether PU films incubated for 10, 30, and 60 days did not show any indication of fungal growth. On the contrary, when using oxygen in the UV pre-treatment a layer of fungi spores covered the sample, indicating a great adherence of the microorganisms to the polymer. However, if acrylic acid vapors were used during the UV pre-treatment, a visible attack by the entomopathogenic fungi was observed. SEM and FTIR-ATR data showed clear evidence of fungal development: growth and ramifications of hyphae on the polymer surface with the increase in UV pre-treatment time and fungus incubation time. The results indicated that the simple UV surface activation process has proven to be a promising alternative for polyether PU waste management.

  10. Design of algal film photobioreactors: material surface energy effects on algal film productivity, colonization and lipid content.

    Science.gov (United States)

    Genin, Scott N; Stewart Aitchison, J; Grant Allen, D

    2014-03-01

    A parallel plate air lift reactor was used to examine the growth kinetics of mixed culture algal biofilms grown on various materials (acrylic, glass, polycarbonate, polystyrene and cellulose acetate). The growth kinetics of the algal biofilms were non-linear overall and their overall productivities ranged from 1.10-2.08g/m(2)day, with those grown on cellulose acetate having the highest productivity. Overall algal biofilm productivity was largely explained by differences in the colonization time which in turn was strongly correlated to the polar surface energy of the material, but weakly correlated to water-material contact angle. When colonization time was taken into account, the productivity for all materials except acrylic was not significantly different at approximately 2g/m(2)/day. Lipid content of the algal biofilms ranged from 6% to 8% (w/w) and was not correlated to water-material contact angle or polar surface energy. The results have potential application for selecting appropriate materials for algal film photobioreactors.

  11. Modeling of Microwave Reflection from the Surface of Water Basins with Spills of Water-Cut Oil

    Science.gov (United States)

    Krotikov, V. D.; Pelushenko, S. A.; Rakut', I. V.; Savelyev, V. Yu.

    2015-06-01

    We consider specific features of reflection of microwaves from the surface of a water basin for the two-layer model of oil spills, which are determined by a water-cut-oil film. Within the spill model, the dielectric properties of water were allowed for in accordance with the Debye theory, and the dielectric properties of the water-cut oil, in accordance with the theory developed for binary systems. The data about variations in the values of reflection coefficients depending on the frequency, viewing angle, thickness of the oil film, and moisture content in the film are obtained. The dependences of reflection coefficients on the film thickness are determined for various values of volume content of the water fraction in oil. Complex values of the dielectric permittivity of oil-water emulsions with preset volume moisture content are found. Describing the obtained dependences of the complex dielectric permittivity of the emulsion on the volume moisture content requires application of asymmetrical formulas for the mixture of polar and nonpolar fluids.

  12. Carbon dioxide and water adsorption on highly epitaxial Delafossite CuFeO2 thin film

    Science.gov (United States)

    Rojas, S.; Joshi, T.; Borisov, P.; Sarabia, M.; Lederman, D.; Cabrera, A. L.

    2015-03-01

    Thermal programmed desorption (TPD) of CO2 and H2O from a 200 nm thick CuFeO2 Delafossite surface was performed in a standard UHV chamber, The CuFeO2 thin film grown using Pulsed Laser Deposition (PLD) over an Al2O3 (0001) substrate with controlled O2 atmosphere resulted with highly epitaxial crystal structure. The adsorption/desorption of CO2 and H2O process was also monitored with X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Our results revealed that carbon dioxide interacts with CuFeO2 forming Fe carbonates compounds on its surface. Hydroxides were also formed on the surface due to water presence. Using TPD data, Arrhenius plots for CO2 and water desorption were done and activation energy for desorption was obtained. Funds FONDECyT 1130372; Thanks to P. Ferrari.

  13. Fabrication of endothelial progenitor cell capture surface via DNA aptamer modifying dopamine/polyethyleneimine copolymer film

    Science.gov (United States)

    Li, Xin; Deng, Jinchuan; Yuan, Shuheng; Wang, Juan; Luo, Rifang; Chen, Si; Wang, Jin; Huang, Nan

    2016-11-01

    Endothelial progenitor cells (EPCs) are mainly located in bone marrow and circulate, and play a crucial role in repairmen of injury endothelium. One of the most promising strategies of stents designs were considered to make in-situ endothelialization in vivo via EPC-capture biomolecules on a vascular graft to capture EPCs directly from circulatory blood. In this work, an EPC specific aptamer with a 34 bases single strand DNA sequence was conjugated onto the stent surface via dopamine/polyethyleneimine copolymer film as a platform and linker. The assembled density of DNA aptamer could be regulated by controlling dopamine percentage in this copolymer film. X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) and fluorescence test confirmed the successful immobilization of DNA aptamer. To confirm its biofunctionality and cytocompatibility, the capturing cells ability of the aptamer modified surface and the effects on the growth behavior of human umbilical vein endothelial cells (HUVECs), smooth muscle cells (SMCs) were investigated. The aptamer functionalized sample revealed a good EPC-capture ability, and had a cellular friendly feature for both EPC and EC growth, while not stimulated the hyperplasia of SMCs. And, the co-culture experiment of three types of cells confirmed the specificity capturing of EPCs to aptamer modified surface, rather than ECs and SMCs. These data suggested that this aptamer functionalized surface may have a large potentiality for the application of vascular grafts with targeted endothelialization.

  14. Surface and Electrical Properties of NiCr Thin Films Prepared by DC Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jicheng; TIAN Li; YAN Jianwu

    2008-01-01

    Several batches of NiCr alloy thin films with different thickness were prepared in a multi-targets magnetron sputtering apparatus by changing sputtering time while keeping sputtering target power of Ni and Cr fixed. Then the as-deposited films were characterized by energy-dispersive X-Ray spectrometer (EDX),Atomic Force Microscope (AFM) and four-point probe (FPP) to measure surface grain size, roughness and sheet resistance. The film thickness was measured by Alpha-Step IQ Profilers. The thickness dependence of surface roughness, lateral grain size and resistivity was also studied. The experimental results show that the grain size increases with film thickness and the surface roughness reaches the order of nanometer at all film thickness. The as-deposited film resistivity decreases with film thickness.

  15. Source Water Assessment for the Las Vegas Valley Surface Waters

    Science.gov (United States)

    Albuquerque, S. P.; Piechota, T. C.

    2003-12-01

    The 1996 amendment to the Safe Drinking Water Act of 1974 created the Source Water Assessment Program (SWAP) with an objective to evaluate potential sources of contamination to drinking water intakes. The development of a Source Water Assessment Plan for Las Vegas Valley surface water runoff into Lake Mead is important since it will guide future work on source water protection of the main source of water. The first step was the identification of the watershed boundary and source water protection area. Two protection zones were delineated. Zone A extends 500 ft around water bodies, and Zone B extends 3000 ft from the boundaries of Zone A. These Zones extend upstream to the limits of dry weather flows in the storm channels within the Las Vegas Valley. After the protection areas were identified, the potential sources of contamination in the protection area were inventoried. Field work was conducted to identify possible sources of contamination. A GIS coverage obtained from local data sources was used to identify the septic tank locations. Finally, the National Pollutant Discharge Elimination System (NPDES) Permits were obtained from the State of Nevada, and included in the inventory. After the inventory was completed, a level of risk was assigned to each potential contaminating activity (PCA). The contaminants of concern were grouped into five categories: volatile organic compounds (VOCs), synthetic organic compounds (SOCs), inorganic compounds (IOCs), microbiological, and radionuclides. The vulnerability of the water intake to each of the PCAs was assigned based on these five categories, and also on three other factors: the physical barrier effectiveness, the risk potential, and the time of travel. The vulnerability analysis shows that the PCAs with the highest vulnerability rating include septic systems, golf courses/parks, storm channels, gas stations, auto repair shops, construction, and the wastewater treatment plant discharges. Based on the current water quality

  16. Reduced glass transition temperatures in thin polymer films: surface effect or artifact?

    Science.gov (United States)

    Bäumchen, O; McGraw, J D; Forrest, J A; Dalnoki-Veress, K

    2012-08-03

    We have examined the direct effect of manipulating the number of free surfaces on the measured glass transition temperature T(g) of thin polystyrene films. Thin films in the range 35 nm thickness and refractive index of freestanding films. By noting the change in slope in each of these quantities, a T(g) value can be assigned in quantitative agreement with previously reported results. For thin freestanding films this value is reduced from that of the bulk. The exact same films are then transferred to a Si substrate and the T(g) of the resulting supported film was determined. The T(g) values of the now supported films are the same as the bulk value and the same as previous reports of similar supported films. These experiments unambiguously show that free interfaces are the dominant cause of the T(g) reductions for the film thicknesses studied.

  17. Experimental Study on the Surface Modification of Ultra Thin DLC Films

    Institute of Scientific and Technical Information of China (English)

    ZHU Shou-xing; ZHU Shi-gen

    2005-01-01

    School of Mechanical Engineering, Donghua University, Shanghai 200051Surface modification of Diamond-like carbon (DLC) films was carried out in order to estimate the reliability of the ultra thin DLC films. The wear resistance, conductivity and mechatronic reliability of the films were studied by contact atomic force microscope (AFM), electric force microscope (EFM) and conductive AFM. The failure mechanism of pits formed and the reason for conductivity changed of DLC films were examined.

  18. Surface relaxations as a tool to distinguish the dynamic interfacial properties of films formed by normal and diseased meibomian lipids.

    Science.gov (United States)

    Georgiev, Georgi As; Yokoi, Norihiko; Ivanova, Slavyana; Tonchev, Vesselin; Nencheva, Yana; Krastev, Rumen

    2014-08-14

    The surface properties of human meibomian lipids (MGS), the major constituent of the tear film (TF) lipid layer, are of key importance for TF stability. The dynamic interfacial properties of films by MGS from normal eyes (nMGS) and eyes with meibomian gland dysfunction (dMGS) were studied using a Langmuir surface balance. The behavior of the samples during dynamic area changes was evaluated by surface pressure-area isotherms and isocycles. The surface dilatational rheology of the films was examined in the frequency range 10(-5) to 1 Hz by the stress-relaxation method. A significant difference was found, with dMGS showing slow viscosity-dominated relaxation at 10(-4) to 10(-3) Hz, whereas nMGS remained predominantly elastic over the whole range. A Cole-Cole plot revealed two characteristic processes contributing to the relaxation, fast (on the scale of characteristic time τ 100 s), the latter prevailing in dMGS films. Brewster angle microscopy revealed better spreading of nMGS at the air-water interface, whereas dMGS layers were non-uniform and patchy. The distinctions in the interfacial properties of the films in vitro correlated with the accelerated degradation of meibum layer pattern at the air-tear interface and with the decreased stability of TF in vivo. These results, and also recent findings on the modest capability of meibum to suppress the evaporation of the aqueous subphase, suggest the need for a re-evaluation of the role of MGS. The probable key function of meibomian lipids might be to form viscoelastic films capable of opposing dilation of the air-tear interface. The impact of temperature on the meibum surface properties is discussed in terms of its possible effect on the normal structure of the film.

  19. Surface chemistry and spectroscopy of UG8 asphaltene Langmuir film, part 2.

    Science.gov (United States)

    Orbulescu, Jhony; Mullins, Oliver C; Leblanc, Roger M

    2010-10-05

    While there has been much focus on asphaltenes in toluene, there has been much less focus on asphaltenes in other solvents. It is important to quantify characteristics of asphaltenes in solvents besides toluene in order to better assess their molecular architecture as well as their fundamental aggregation characteristics. The present work focuses on the investigation of UG8 asphaltene Langmuir films at the air-water interface using chloroform as spreading solvent. The results are compared to the results recently obtained using toluene as spreading solvent. Surface pressure-area isotherms and UV-vis spectroscopy indicate that asphaltenes form smaller nanoaggregates in chloroform than in toluene in similar concentration ranges. Still these nanoaggreates share common features with those in toluene. From the surface pressure-area and compression-decompression isotherms, Brewster angle microscopy, and p-polarized infrared reflection-absorption spectroscopy, it was concluded that small size aggregates are spread on the water surface and the compression of the film leads to formation of large aggregates. The films (Langmuir-Schaefer and Langmuir-Blodgett) studied by atomic force microscopy reveal the existence of nanoaggregates spread on the water surface that coexist with large aggregates formed during compression. In addition to these findings, the spreading solvent, chloroform, allows the determination of asphaltene absorption bands using in situ UV-vis spectroscopy at the air-water interface after 15 min waiting time period. The absorbance data carried out after waiting a time period of 1 h shows similar features with the ones carried out after only 15 min; therefore, there is no need to wait 1 h as in the case when toluene is used as spreading solvent. A comparison of the data obtained from chloroform and toluene shows that smaller aggregate sizes are obtained from chloroform as suggested from the surface pressure-area isotherm, in situ UV-vis spectroscopy, and

  20. Surface Hydrophilicity and Antifungal Properties of TiO2 Films Coated on a Co-Cr Substrate.

    Science.gov (United States)

    Huang, Lijuan; Jing, Shuanglin; Zhuo, Ou; Meng, Xiangfeng; Wang, Xizhang

    2017-01-01

    The purpose of this study was to deposit a thin layer of TiO2 on a Co-Cr substrate, serving as a deactivation film protecting the metallic fitting surface. The crystalline structure and surface morphology of the film were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A scratch tester was used to examine the adhesion strength between the TiO2 film and the Co-Cr substrate. The water contact angles and antifungal efficacy against C. albicans of the TiO2-deposited Co-Cr samples were investigated and further compared with those of uncoated Co-Cr substrates. The results indicated that a pure anatase microstructure and dense and smooth surface texture as well as strong binding to the underlying metallic surface were obtained. The originally hydrophobic Co-Cr alloy surface turned hydrophilic after TiO2 film coating. Most importantly, the TiO2-coated surface showed a superior antifungal capability under UV-irradiation compared to those without TiO2 coating. This work contains meaningful results for the development of a new metallic framework coating with improved hydrophilicity and antifungal properties.

  1. Surface Hydrophilicity and Antifungal Properties of TiO2 Films Coated on a Co-Cr Substrate

    Directory of Open Access Journals (Sweden)

    Lijuan Huang

    2017-01-01

    Full Text Available The purpose of this study was to deposit a thin layer of TiO2 on a Co-Cr substrate, serving as a deactivation film protecting the metallic fitting surface. The crystalline structure and surface morphology of the film were characterized by X-ray diffraction (XRD and scanning electron microscopy (SEM. A scratch tester was used to examine the adhesion strength between the TiO2 film and the Co-Cr substrate. The water contact angles and antifungal efficacy against C. albicans of the TiO2-deposited Co-Cr samples were investigated and further compared with those of uncoated Co-Cr substrates. The results indicated that a pure anatase microstructure and dense and smooth surface texture as well as strong binding to the underlying metallic surface were obtained. The originally hydrophobic Co-Cr alloy surface turned hydrophilic after TiO2 film coating. Most importantly, the TiO2-coated surface showed a superior antifungal capability under UV-irradiation compared to those without TiO2 coating. This work contains meaningful results for the development of a new metallic framework coating with improved hydrophilicity and antifungal properties.

  2. Controlled reflectance surfaces with film-coupled colloidal nanoantennas

    Science.gov (United States)

    Moreau, Antoine; Ciraci, Cristian; Mock, Jack J.; Hill, Ryan T.; Wang, Qiang; Wiley, Benjamin J.; Chilkoti, Ashutosh; Smith, David R.

    2013-01-01

    Efficient and tunable absorption is essential for a variety of applications, such as the design of controlled emissivity surfaces for thermophotovoltaic devices1; tailoring of the infrared spectrum for controlled thermal dissipation2; and detector elements for imaging3. Metamaterials based on metallic elements are particularly efficient as absorbing media, because both the electrical and the magnetic properties of a metamaterial can be tuned by structured design4. To date, metamaterial absorbers in the infrared or visible range have been fabricated using lithographically patterned metallic structures2,5–9, making them inherently difficult to produce over large areas and hence reducing their applicability. We demonstrate here an extraordinarily simple method to create a metamaterial absorber by randomly adsorbing chemically synthesized silver nanocubes onto a nanoscale thick polymer spacer layer on a gold film –making no effort to control the spatial arrangement of the cubes on the film– and show that the film-coupled nanocubes provide a reflectance spectrum that can be tailored by varying the geometry. Each nanocube is the optical analog of the well-known grounded patch antenna, with a nearly identical local field structure that is modified by the plasmonic response of the metal dielectric function, and with an anomalously large absorption efficiency that can be partly attributed to an interferometric effect10. The absorptivity of large surface areas can be controlled using this method, at scales out of reach of lithographic approaches like e-beam lithography otherwise required to manipulate matter at the nanometer scale. PMID:23222613

  3. Microarray of neuroblastoma cells on the selectively functionalized nanocrystalline diamond thin film surface

    Science.gov (United States)

    Park, Young-Sang; Son, Hyeong-Guk; Kim, Dae-Hoon; Oh, Hong-Gi; Lee, Da-Som; Kim, Min-Hye; Lim, Ki-Moo; Song, Kwang-Soup

    2016-01-01

    Nanocrystalline diamond (NCD) film surfaces were modified with fluorine or oxygen by plasma treatment in an O2 or C3F8 gas environment in order to induce wettability. The oxygenated-NCD (O-NCD) film surface was hydrophilic and the fluorinated-NCD (F-NCD) surface was hydrophobic. The efficiency of early cell adhesion, which is dependent on the wettability of the cell culture plate and necessary for the growth and proliferation of cells, was 89.62 ± 3.92% on the O-NCD film and 7.78 ± 0.77% on the F-NCD film surface after 3 h of cell culture. The wettability of the NCD film surface was artificially modified using a metal mask and plasma treatment to fabricate a micro-pattern. Four types of micro-patterns were fabricated (line, circle, mesh, and word) on the NCD film surface. We precisely arrayed the neuroblastoma cells on the micro-patterned NCD film surfaces by controlling the surface wettability and cell seeding density. The neuroblastoma cells adhered and proliferated along the O-NCD film surface.

  4. Organic thin films and surfaces directions for the nineties

    CERN Document Server

    Ulman, Abraham

    1995-01-01

    Physics of Thin Films has been one of the longest running continuing series in thin film science consisting of 20 volumes since 1963. The series contains some of the highest quality studies of the properties ofvarious thin films materials and systems.In order to be able to reflect the development of todays science and to cover all modern aspects of thin films, the series, beginning with Volume 20, will move beyond the basic physics of thin films. It will address the most important aspects of both inorganic and organic thin films, in both their theoretical as well as technological aspects. Ther

  5. Lipases efficiently stearate and cutinases acetylate the surface of arabinoxylan films.

    Science.gov (United States)

    Stepan, A M; Anasontzis, G E; Matama, T; Cavaco-Paulo, A; Olsson, L; Gatenholm, P

    2013-08-10

    This is the first report on successful enzyme catalyzed surface esterification of hemicellulose films. Enzyme catalyzed surface acetylation with vinyl acetate and stearation with vinyl stearate were studied on rye arabinoxylan (AX) films. Different surface analytical techniques (FT-IR, TOF-SIMS, ESCA, CA) show that lipases from Mucor javanicus, Rhizopus oryzae and Candida rugosa successfully surface stearate AX films and that a cutinase from Fusarium solani pisi surface acetylates these films. The specificities of cutinase and lipases were also compared, and higher activity was observed for lipases utilizing long alkyl chain substrates while higher activity was observed for cutinase utilizing shorter alkyl chain substrates. The contact angle analysis showed films with increased initial hydrophobicity on the surfaces. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang, E-mail: liuyang@cczu.edu.cn [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China); Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Shen, Xin; Zhou, Huan [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China); Wang, Yingjun [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Deng, Linhong, E-mail: dlh@cczu.edu.cn [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou 213164 (China)

    2016-05-01

    Graphical abstract: - Highlights: • Chitosan film was modified by surface grafting of citric acid. • The modified film has good hydrophilicity and moisture-retaining capacity. • The citric acid grafting treatment significantly promote the biomineralization. • MC3T3-E1 osteoblasts research confirms the biocompatibility of the film. - Abstract: 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.

  7. Surface morphology and photoluminescence properties of ZnO thin films obtained by PLD

    Institute of Scientific and Technical Information of China (English)

    FAN Xi-mei; LIAN Jian-she; GUO Zuo-xing; JIANG Qing

    2005-01-01

    ZnO thin films on Si(111) substrate were deposited by laser ablation of Zn target in oxygen reactive atmosphere, Nd-YAG laser with wavelength of 1 064 nm was used as laser source. XRD and FESEM microscopy were applied to characterize the structure and surface morphology of the deposited ZnO films. The optical properties of the ZnO thin films were characterized by photoluminescence. The UV and deep level (yellow-green) light were observed from the films. The UV light is the intrinsic property and deep level light is attributed to the existence of antisite defects (OZn). The intensity of UV and deep level light depends strongly on the surface morphology and is explained by the surface roughness of ZnO film. A strongly UV emission can be obtained from ZnO film with surface roughness in nanometer range.

  8. Effect of demulsifiers on interfacial films and stability of water-in-oil emulsions stabilized by asphaltenes

    Energy Technology Data Exchange (ETDEWEB)

    Baydak, E.N.; Yarranton, H.W.; Ortiz, D. [Calgary Univ., AB (Canada). Dept. of Chemical and Petroleum Engineering; Moran, K. [Syncrude Research Centre, Edmonton, AB (Canada)

    2008-07-01

    In water-in-toluene/heptane emulsions stabilized by asphaltenes, there is a correlation between emulsion stability and the compressibility of interfacial asphaltene films. In order to determine if this correlation for emulsion stability is more generally applicable, a study was conducted in which the effect of commercial demulsifiers on the film properties and emulsion stability was measured. A naphthenic acid (NA) and a branched dodecylbenzene sulfonic acid (DDBS) were examined. Surface pressure isotherms were measured in a drop shape analyzer for droplets of asphaltenes, toluene, and heptane surrounded by a solution of water and surfactant. The experimental variables included heptane, asphaltene and surfactant concentration along with aging time. The compressibilities of the interfacial films were determined from the slope of the surface pressure isotherms. Water-in-oil emulsions were prepared from the same solutions. Emulsion stability was evaluated in terms of the free water evolved after a treatment of centrifugation and heating. Initial results suggest that the demulsifiers increase the compressibility of the interfacial films. In most cases, the addition of the demulsifier increased emulsion stability. The timing of the addition of the demulsifier or the phase to which it was added did not appear to have an influence on the results. It was concluded that the reduction in interfacial tension from the added surfactant may inhibit coalescence more than the weakening of the interfacial film promotes coalescence. 1 ref.

  9. PREFACE: International Conference on Solid Films and Surfaces (ICSFS 2014)

    Science.gov (United States)

    Achete, C. A.; Almeida, C. M.; Cremona, M.; Rocca, M.; Stavale, F.

    2015-03-01

    Foreword The 17th ICSFS took place at the wonderful city of Rio de Janeiro, Brazil from the 8th to the 11th of September, 2014. The conference focused on recent advances in controlling and characterizing the physical and chemical properties of films and surfaces, with a particular emphasis on materials for electronic, photonic and spintronic applications. In addition, themes of bio-functionalized structures and devices were strongly discussed in the ICSFS, covering interdisciplinary nano and nano-bio science and technology. The conference has promoted, in various sub-fields of materials surfaces and thin films, an excellent forum for exchange of ideas, presentation of technical achievements and discussion of future directions in the field. In this volume of the IOP Conference Series: Materials Science and Engineering we are glad to present 11 peer-reviewed ICSFS contributing papers. The cross-disciplinary nature of conference topics is clearly reflected in these Proceedings' contents. The themes discussed ranged from those close to more traditional condensed matter physics, such as semiconductor surfaces to physical chemistry related issues. The Proceedings were organized in accordance with contributions presented at the Conference. We were glad with the presence of over 160 participants, including 24 invited and plenary talks and over 50 oral contributions. We strongly believe that these Proceedings will be useful for a wide audience of those interested in basic and applied surfaces and thin solid interfaces. Acknowledgment We would like to acknowledge the hard work, professional skills and efficiency of the team which oversaw the general organization, particularly of Dicom (Social Communication Division) from the National Institute of Metrology, Quality and Technology, Inmetro (Brazil). We also would like to thank all the invited speakers and session chairs for making the meeting such a great success. The Conference was supported and sponsored by Academia

  10. How Water Advances on Superhydrophobic Surfaces

    Science.gov (United States)

    Schellenberger, Frank; Encinas, Noemí; Vollmer, Doris; Butt, Hans-Jürgen

    2016-03-01

    Superliquid repellency can be achieved by nano- and microstructuring surfaces in such a way that protrusions entrap air underneath the liquid. It is still not known how the three-phase contact line advances on such structured surfaces. In contrast to a smooth surface, where the contact line can advance continuously, on a superliquid-repellent surface, the contact line has to overcome an air gap between protrusions. Here, we apply laser scanning confocal microscopy to get the first microscopic videos of water drops advancing on a superhydrophobic array of micropillars. In contrast to common belief, the liquid surface gradually bends down until it touches the top face of the next micropillars. The apparent advancing contact angle is 180°. On the receding side, pinning to the top faces of the micropillars determines the apparent receding contact angle. Based on these observations, we propose that the apparent receding contact angle should be used for characterizing superliquid-repellent surfaces rather than the apparent advancing contact angle and hysteresis.

  11. Collision Dynamics and Solvation of Water Molecules in a Liquid Methanol Film

    CERN Document Server

    Thomson, Erik S; Andersson, Patrik U; Marković, Nikola; Pettersson, Jan B C; 10.1021/jz200929y

    2011-01-01

    Environmental molecular beam experiments are used to examine water interactions with liquid methanol films at temperatures from 170 K to 190 K. We find that water molecules with 0.32 eV incident kinetic energy are efficiently trapped by the liquid methanol. The scattering process is characterized by an efficient loss of energy to surface modes with a minor component of the incident beam that is inelastically scattered. Thermal desorption of water molecules has a well characterized Arrhenius form with an activation energy of 0.47{\\pm}0.11 eV and pre-exponential factor of 4.6 {\\times} 10^(15{\\pm}3) s^(-1). We also observe a temperature dependent incorporation of incident water into the methanol layer. The implication for fundamental studies and environmental applications is that even an alcohol as simple as methanol can exhibit complex and temperature dependent surfactant behavior.

  12. Preparation, characterization and dissolution of passive oxide film on the 400 series stainless steel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sathyaseelan, V.S.; Rufus, A.L.; Chandramohan, P.; Subramanian, H.; Velmurugan, S., E-mail: svelu@igcar.gov.in

    2015-12-15

    Full system decontamination of Primary Heat Transport (PHT) system of Pressurised Heavy Water Reactors (PHWRs) resulted in low decontamination factors (DF) on stainless steel (SS) surfaces. Hence, studies were carried out with 403 SS and 410 SS that are the material of construction of “End-Fitting body” and “End-Fitting Liner tubes”. Three formulations were evaluated for the dissolution of passive films formed over these alloys viz., i) Two-step process consisting of oxidation and reduction reactions, ii) Dilute Chemical Decontamination (DCD) and iii) High Temperature Process. The two-step and high temperature processes could dissolve the oxide completely while the DCD process could remove only 60%. Various techniques like XRD, Raman spectroscopy and SEM-EDX were used for assessing the dissolution process. The two-step process is time consuming, laborious while the high temperature process is less time consuming and is recommended for SS decontamination. - Graphical abstract: SEM micrograph of the oxide film formed in an autoclave over the 403 SS and 410 SS surfaces, the “End-Fitting Body and End-Fitting Liner” materials of Pressurized Heavy Water Reactor (PHWR). - Highlights: • The oxides formed over 403 and 410 SS are spinels similar to magnetite. • Oxide is duplex in nature with chromium rich inner layer. • Dilute Chemical Decontamination process could dissolve only 60% of the oxide. • Oxidation-Reduction process dissolves 100% oxide layer but time consuming. • High Temperature process is 100% efficient and less time consuming.

  13. Direct measurement of the surface dynamics of supercooled liquid-glycerol by optical scanning a film

    Institute of Scientific and Technical Information of China (English)

    Zhang Fang; Zhang Guo-Feng; Dong Shuang-Li; Sun Jian-Hu; Chen Rui-Yun; Xiao Lian-Tuan; Jia Suo-Tang

    2009-01-01

    The surface dynamics of supercooled liquid-glycerol is studied by scanning the thickness of the glycerol film with single photon detection. Measurements are performed at room temperature well above the glycerol's glass transition temperature. It is shown that the surface dynamics of the glycerol film is very sensitive to the temperature. The linear relationship between the thickness of the film and the viscosity predicted by the Vogel-Fulcher-Tammann-Hesse (VFTH) law is also presented experimentally.

  14. Improved performance of Mg-Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

    Science.gov (United States)

    La, Mao; Zhou, Huaijuan; Li, Ning; Xin, Yunchuan; Sha, Ren; Bao, Shanhu; Jin, Ping

    2017-05-01

    The magnesium based switchable mirrors can reversibly change their optical properties between the transparent and the reflective state as a result of hydrogenation and dehydrogenation. These films can potentially be applied as new energy-saving windows, by controlling the transmittance of solar radiation through the regulation of their reflective state. In this study, magnesium-yttrium (Mg-Y) alloy thin films were prepared using a DC magnetron sputtering method. However, the luminous transmittance in the transparent state and the switching durability of switchable mirrors are too poor to satisfy practical demands. In order to improve the films switching durability, luminous transmittance and the surface functionalization, polytetrafluoroethylene (PTFE) was coated with thermal vacuum deposition for use as the top layer of Mg-Y/Pd switchable mirrors. The PTFE layer had a porous network structure and exhibited a superhydrophobic surface with a water contact angle of approximately 152°. By characterization, PTFE thin films shows the excellent protection role against the oxidization of Mg, the switching durability of the films were improved 3 times, and also shows the antireflection role the luminous transmission of films was enhanced by 7% through the top covered with PTFE.

  15. Role of surface states in the Casimir force between semiconducting films

    CERN Document Server

    Govoni, Marco; Benassi, Andrea

    2010-01-01

    We present results of first principle calculations of the Casimir force between Si films of nanometric size, which show that it depends significantly upon the configuration of the surface atoms, and give evidence of the importance of surface states.

  16. The Soil Characteristic Curve at Low Water Contents: Relations to Specific Surface Area and Texture

    DEFF Research Database (Denmark)

    Resurreccion, Augustus; Møldrup, Per; Schjønning, Per;

    Accurate description of the soil-water retention curve (SWRC) at low water contents is important for simulating water dynamics, plant-water relations, and microbial processes in surface soil. Soil-water retention at soil-water matric potential of less than -10 MPa, where adsorptive forces dominate...... that measurements by traditional pressure plate apparatus generally overestimated water contents at -1.5 MPa (plant wilting point). The 41 soils were classified into four textural classes based on the so-called Dexter index n (= CL/OC), and the Tuller-Or (TO) general scaling model describing the water film...... thickness at a given soil-water matric potential (low organic soils with n > 10, the estimated SA from the dry soil-water retention was in good agreement with the SA measured using ethylene glycol monoethyl ether (SA_EGME). A strong relationship between the ratio...

  17. Convergent surface water distributions in U.S. cities

    Science.gov (United States)

    M.K. Steele; J.B. Heffernan; N. Bettez; J. Cavender-Bares; P.M. Groffman; J.M. Grove; S. Hall; S.E. Hobbie; K. Larson; J.L. Morse; C. Neill; K.C. Nelson; J. O' Neil-Dunne; L. Ogden; D.E. Pataki; C. Polsky; R. Roy Chowdhury

    2014-01-01

    Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However, the scope and consequences of surface water redistribution at broad spatial scales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and...

  18. Surface treatment of polyimide film for metal magnetron deposition in vacuum

    Science.gov (United States)

    Petrov, V.; Vertyanov, D.; Timoshenkov, S.; Nikolaev, V.

    2014-12-01

    This paper brings forward a solution for acquisition of good quality metallization layers on the polyimide substrate by magnetron deposition in vacuum environment. Different film type structures have been analyzed after refining and activation surface treatment operations. Positive effect was shown after the application of polyimide lacquer for surface dielectric film planarization and for structural defects elimination.

  19. Organogel-based thin films for self-cleaning on various surfaces.

    Science.gov (United States)

    Liu, Hongliang; Zhang, Pengchao; Liu, Mingjie; Wang, Shutao; Jiang, Lei

    2013-08-27

    Self-cleaning on various surfaces is obtained using the facile approach of modifying the surface with a thin organogel film. The film not only absorbs oil but also holds it in a crosslinked network, which endows the material with excellent self-cleaning properties. This facile method can be applied to various common engineering metals.

  20. Effects of water blowers on service life of combustion chamber heating surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Habryka, A. (Zaklad Techniki Cieplnej i Gospodarki Energetycznej (Poland))

    1990-07-01

    Discusses control of fouling in steam generators of coal-fired power plants and the performance of water jet equipment. Heating surfaces of combustion chambers were monitored by optical probes, industrial television cameras, photo- and film cameras. Continuous observation was accompanied by temperature measurements with thermocouples. Negative effects of water jet application and experience gained in Poland, Estonia and in the FRG concerning periods of cleaning cycles are considered. Improved heating surface cleaning procedures and application of water-jet cleaners of the type used in the Thierbach and Jaenschwalde power plants (FRG) are recommended. 8 refs.

  1. ITO-MgF2 Film Development for PowerSphere Polymer Surface Protection

    Science.gov (United States)

    Hambourger, Paul D.; Kerslake, Thomas W.; Waters, Deborah L.

    2004-01-01

    Multi-kilogram class microsatellites with a PowerSphere electric power system are attractive for fulfilling a variety of potential NASA missions. However, PowerSphere polymer surfaces must be coated with a film that has suitable electrical sheet resistivity for electrostatic discharge control, be resistant to atomic oxygen attack, be transparent to ultraviolet light for composite structure curing and resist ultraviolet light induced darkening for efficient photovoltaic cell operation. In addition, the film must be tolerant of polymer layer folding associated with launch stowage of PowerSphere inflatable structures. An excellent film material candidate to meet these requirements is co-sputtered, indium oxide (In2O3) - tin oxide (SnO2), known as 'ITO', and magnesium fluoride (MgF2). While basic ITO-MgF2 film properties have been the subject of research over the last decade, further research is required in the areas of film durability for space-inflatable applications and precise film property control for large scale commercial production. In this paper, the authors present film durability results for a folded polymer substrate and film resistance to vacuum UV darkening. The authors discuss methods and results in the area of film sheet resistivity measurement and active control, particularly dual-channel, plasma emission line measurement of ITO and MgF2 plasma sources. ITO-MgF2 film polymer coupon preparation is described as well as film deposition equipment, procedures and film characterization. Durability testing methods are also described. The pre- and post-test condition of the films is assessed microscopically and electrically. Results show that an approx. 500A ITO-18vol% MgF2 film is a promising candidate to protect PowerSphere polymer surfaces for Earth orbit missions. Preliminary data also indicate that in situ film measurement methods are promising for active film resistivity control in future large scale production. Future film research plans are also

  2. A molecular dynamics study on surface properties of supercooled water

    Institute of Scientific and Technical Information of China (English)

    Lü; Yongjun

    2006-01-01

    [1]Basu J K,Hazra S,Sanyal M K.Growth mechanism of Langmuir-Blodgett films.Phys Rev Lett,1999,82:4675-4678[2]Taylor R S,Shields R L.Molecular-dynamics simulations of the ethanol liquid-vapor interface.J Chem Phys,2003,119:12569-12576[3]Velev O D,Gurkov T D,Ivanov I B,et al.Abnormal thickness and stability of nonequilibrium liquid films.Phys Rev Lett,1995,75:264-267[4]Weng J G,Park S,Lukes J R,et al.Molecular dynamics investigation of thickness effect on liquid films.J Chem Phys,2000,113:5917-5923[5]Zakharov V V,Brodskaya E N,Laaksonen A.Surface tension of water droplets:A molecular dynamics study of model and size dependencies.J Chem Phys,1997,107:10675-10683[6]Wang J Z,Chen M,Guo Z Y.A two-dimensional molecular dynamics simulation of liquid-vapor nucleation.Chin Sci Bull,2003,48(7):623-626[7]Guissani Y,Guillot B.A computer simulation study of the liquid-vapor coexistence curve of water.J Chem Phys,1993,98:8221-8235[8]Wilson M A,Pohorille A,Pratt L R.Surface potential of the water liquid-vapor interface.J Chem Phys,1988,88:3281-3285[9]Alejandre J,Tildesley D J,Chapela G A.Molecular dynamics simulation of the orthobaric densities and surface tension of water.J Chem Phys,1995,102:4574-4583[10]Matsumoto M,Kataoka Y.Study on liquid-vapor interface of water (Ⅰ):Simulational results of thermodynamic properties and orientational structure.J Chem Phys,1988,88:3233-3245[11]Floriano M A,Angell C A.Surface tension and molar surface free energy and entropy of water to-27.2℃.J Phys Chem,1990,94:4199-4202[12]Jorgensen W L,Chandrasekhar J,Madura J D.Comparison of simple potential functions for simulating liquid water.J Chem Phys,1993,79:926-935[13]Berendsen H J C,Grigera J R,Straatsma T P.The missing term in effective pair potentials.J Phys Chem,1987,91:6269-6271[14]Arbuckle B W,Clancy P.Effects of the Ewald sum on the free energy of the extended simple point charge model for water.J Chem Phys,2002,116:5090-5098[15]Tarazona P,Chacon E,Reinaldo-Falagan M,et al

  3. Electromagnetic Scattering from Rough Sea Surface with PM Spectrum Covered by an Organic Film

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; GUO Li-Xin; WANG An-Qi; WU Zhen-Sen

    2011-01-01

    The rough sea surface covered by an organic film will cause attenuation of capillarity waves, which implies that the organic films play an important role in rough sea surface processes. We focus on a one-dimensional(1D)rough sea surface with the Pierson-Moskowitz(PM)spectrum distributed to the homogeneous insoluble organic slicks. First, the impact of the organic film on the PM surface spectrum is presented, as well as that of the correlation length, the rms height and slope of the rough sea surface. The damping effect of the organic film changes the physical parameters of the rough sea surface. For example, the organic film will reduce the rms height and slopee of the rough sea surface, which results in the attenuation of the high-frequency components of the PM spectrum leading to modification of the surface PM spectrum. Then, the influence of the organic film on the electromagnetic(EM) scattering coefficients from PM rough sea surface covered by the organic film is investigated and discussed in detail, compared with the clean PM rough sea surface through the method of moments.

  4. STEAM-WATER-OXYGEN PROCESSING OF INTERNAL SURFACES OF THE POWER EQUIPMENT

    OpenAIRE

    Манькина, Н. Н.; Кирилина, А. В.

    2015-01-01

    Clearing of adjournment internal surfaces of heating of the various power equipment represents rather difficult problem which ways of the decision not always satisfy experts. In submitted article results of introduction effective technology vapor-water-oxygen clearing (VWOC) with an opportunity of simultaneous passivation and preservation elements of boilers are considered. The data about corrosion resistance formed protective films on internal surfaces of heating boilers after realization va...

  5. Biodegradation improvement of poly(3-hydroxy-butyrate) films by entomopathogenic fungi and UV-assisted surface functionalization.

    Science.gov (United States)

    Kessler, Felipe; Marconatto, Leticia; Rodrigues, Roberta da Silva Bussamara; Lando, Gabriela Albara; Schrank, Augusto; Vainstein, Marilene Henning; Weibel, Daniel Eduardo

    2014-01-05

    Ultraviolet (UV)-assisted surface modification in the presence of oxygen was used as initial step to achieve controlled degradation of poly(3-hydroxy-butyrate), PHB, films by entomopathogenic fungi. Treated surfaces were investigated by surface analysis techniques (water contact angle, Fourier Transformed Infrared Spectroscopy in Attenuated Total Reflectance mode, X-ray Photoelectron Spectroscopy, Near-edge X-ray Absorption Fine Structure, Gel Permeation Chromatography, Optical Microscopy, Scanning Electron Microscopy, and weight loss). After the UV-assisted treatments, new carbonyl groups in new chemical environments were detected by XPS and NEXAFS spectroscopy. The oxidizing atmosphere did not allow the formation of CC bonds, indicating that Norrish Type II mechanism is suppressed during or by the treatments. The higher hydrophilicity and concentration of oxygenated functional groups at the surface of the treated films possibly improved the biodegradation of the films. It was observed a clear increase in the growth of this fungus when oxygenated groups were grafted on the polymers surfaces. This simple methodology can be used to improve and control the degradation rate of PHB films in applications that require a controllable degradation rate.

  6. Selective reflection technique as a probe to monitor the growth of a metallic thin film on dielectric surfaces

    CERN Document Server

    Martins, Weliton Soares; Chevrollier, Martine; de Silans, Thierry Passerat

    2013-01-01

    Controlling thin film formation is technologically challenging. The knowledge of physical properties of the film and of the atoms in the surface vicinity can help improve control over the film growth. We investigate the use of the well-established selective reflection technique to probe the thin film during its growth, simultaneously monitoring the film thickness, the atom-surface van der Waals interaction and the vapor properties in the surface vicinity.

  7. Effect of interface on surface morphology and proton conduction of polymer electrolyte thin films.

    Science.gov (United States)

    Ohira, Akihiro; Kuroda, Seiichi; Mohamed, Hamdy F M; Tavernier, Bruno

    2013-07-21

    To understand the relationship between surface morphology and proton conduction of polymer electrolyte thin films, perfluorinated ionomer Nafion® thin films were prepared on different substrates such as glassy carbon (GC), hydrophilic-GC (H-GC), and platinum (Pt) as models for the ionomer film within a catalyst layer. Atomic force microscopy coupled with an electrochemical (e-AFM) technique revealed that proton conduction decreased with film thickness; an abrupt decrease in proton conductance was observed when the film thickness was less than ca. 10 nm on GC substrates in addition to a significant change in surface morphology. Furthermore, thin films prepared on H-GC substrates with UV-ozone treatment exhibited higher proton conduction than those on untreated GC substrates. However, Pt substrates exhibited proton conduction comparable to that of GCs for films thicker than 20 nm; a decrease in proton conduction was observed at ∼5 nm thick film but was still much higher than for carbon substrates. These results indicate that the number of active proton-conductive pathways and/or the connectivity of the proton path network changed with film thickness. The surface morphology of thinner films was significantly affected by the film/substrate interface and was fundamentally different from that of the bulk thick membrane.

  8. Improvement of the water selectivity of ULTEM poly(ether imide) pervaporation films by an allylamine-plasma-polymerized layer

    OpenAIRE

    Kaba, Meriyam; Raklaoui, Nabil; Guimon, Marie Françoise; Mas, André

    2005-01-01

    International audience; The wettability and surface energy of extruded ULTEM poly(ether imide) films strongly increased (the water contact angle varied from 75 to 38° and the surface energy varied from 45.3 to 59.5 mJ m-2, respectively) with the deposition of an allylamine-plasma-polymerized layer and were characterized with X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy according to the experimental parameters. Pervaporation tests for dehydrating ...

  9. Influence of surface properties on the structure of granular silver films and excitation of localized plasmons

    Science.gov (United States)

    Shcherbinin, D. P.; Konshina, E. A.; Polischuk, V. A.

    2016-04-01

    Granular silver films deposited on a thin insulating film of amorphous hydrogenated carbon ( a-C:H) and transparent conducting electrode (polycrystalline indium tin oxide (ITO) layer) have been investigated by spectroscopy and microscopy methods. The extinction spectra of silver films on the surface of these materials are found to be significantly different. An annealing of silver films causes a blue shift of the peak of plasmon resonance band in the spectrum of silver nanoparticles: by 16 nm on the a-C:H surface and by 94 nm on the ITO surface. Silver films on the surface of a-C:H films are characterized by a narrower band in the extinction spectrum, which is peaked at 446 nm. The changes observed in the optical density of Ag films are related to the change in size and area of nanoparticles. The results of spectral studies of Ag films are in agreement with the data on the nanostructure obtained by scanning electron microscopy and statistical image processing. The spectra of granular silver films are shown to correlate well with the nanoparticle distribution function over the film area.

  10. Bacteriophages as surface and ground water tracers

    Directory of Open Access Journals (Sweden)

    P. Rossi

    1998-01-01

    Full Text Available Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra. In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  11. Bacteriophages as surface and ground water tracers

    Science.gov (United States)

    Rossi, P.; Dörfliger, N.; Kennedy, K.; Müller, I.; Aragno, M.

    Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra). In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  12. Water droplet evaporation from sticky superhydrophobic surfaces

    Science.gov (United States)

    Lee, Moonchan; Kim, Wuseok; Lee, Sanghee; Baek, Seunghyeon; Yong, Kijung; Jeon, Sangmin

    2017-07-01

    The evaporation dynamics of water from sticky superhydrophobic surfaces was investigated using a quartz crystal microresonator and an optical microscope. Anodic aluminum oxide (AAO) layers with different pore sizes were directly fabricated onto quartz crystal substrates and hydrophobized via chemical modification. The resulting AAO layers exhibited hydrophobic or superhydrophobic characteristics with strong adhesion to water due to the presence of sealed air pockets inside the nanopores. After placing a water droplet on the AAO membranes, variations in the resonance frequency and Q-factor were measured throughout the evaporation process, which were related to changes in mass and viscous damping, respectively. It was found that droplet evaporation from a sticky superhydrophobic surface followed a constant contact radius (CCR) mode in the early stage of evaporation and a combination of CCR and constant contact angle modes without a Cassie-Wenzel transition in the final stage. Furthermore, AAO membranes with larger pore sizes exhibited longer evaporation times, which were attributed to evaporative cooling at the droplet interface.

  13. Low-energy electron irradiation induced top-surface nanocrystallization of amorphous carbon film

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Cheng [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Fan, Xue, E-mail: fanx@szu.edu.cn [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China); Diao, Dongfeng, E-mail: dfdiao@szu.edu.cn [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China)

    2016-10-30

    Graphical abstract: Low-energy electron irradiation was proposed to nanocrystallize the top-surface of the as-deposited amorphous carbon film, and sp{sup 2} nanocrystallites formed in the film top-surface within 4 nm thickness. Display Omitted - Abstract: We report a low-energy electron irradiation method to nanocrystallize the top-surface of amorphous carbon film in electron cyclotron resonance plasma system. The nanostructure evolution of the carbon film as a function of electron irradiation density and time was examined by transmission electron microscope (TEM) and Raman spectroscopy. The results showed that the electron irradiation gave rise to the formation of sp{sup 2} nanocrystallites in the film top-surface within 4 nm thickness. The formation of sp{sup 2} nanocrystallite was ascribed to the inelastic electron scattering in the top-surface of carbon film. The frictional property of low-energy electron irradiated film was measured by a pin-on-disk tribometer. The sp{sup 2} nanocrystallized top-surface induced a lower friction coefficient than that of the original pure amorphous film. This method enables a convenient nanocrystallization of amorphous surface.

  14. The influence of ions on water transport in nylon 6 films

    NARCIS (Netherlands)

    Reuvers, N.J.W.; Huinink, H.P.; Fischer, H.R.; Adan, O.C.G.

    2013-01-01

    Nylon 6 films are directly exposed to saline solutions containing mono-valent ions and the water uptake is measured with magnetic resonance imaging (MRI). Both the amount of water uptake and the rate of water uptake are studied. First, the films are exposed to solutions with different concentrations

  15. Gold Incorporated Mesoporous Silica Thin Film Model Surface as a Robust SERS and Catalytically Active Substrate

    Directory of Open Access Journals (Sweden)

    Anandakumari Chandrasekharan Sunil Sekhar

    2016-05-01

    Full Text Available Ultra-small gold nanoparticles incorporated in mesoporous silica thin films with accessible pore channels perpendicular to the substrate are prepared by a modified sol-gel method. The simple and easy spin coating technique is applied here to make homogeneous thin films. The surface characterization using FESEM shows crack-free films with a perpendicular pore arrangement. The applicability of these thin films as catalysts as well as a robust SERS active substrate for model catalysis study is tested. Compared to bare silica film our gold incorporated silica, GSM-23F gave an enhancement factor of 103 for RhB with a laser source 633 nm. The reduction reaction of p-nitrophenol with sodium borohydride from our thin films shows a decrease in peak intensity corresponding to –NO2 group as time proceeds, confirming the catalytic activity. Such model surfaces can potentially bridge the material gap between a real catalytic system and surface science studies.

  16. Electrochemical Water Oxidation by a Catalyst-Modified Metal-Organic Framework Thin Film

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Shaoyang; Pineda-Galvan, Yuliana; Maza, William A.; Epley, Charity C.; Zhu, Jie; Kessinger, Matthew C.; Pushkar, Yulia; Morris, Amanda J. (VP); (Purdue)

    2016-12-15

    Water oxidation, a key component in artificial photosynthesis, requires high overpotentials and exhibits slow reaction kinetics that necessitates the use of stable and efficient heterogeneous water-oxidation catalysts (WOCs). Here, we report the synthesis of UiO-67 metal–organic framework (MOF) thin films doped with [Ru(tpy)(dcbpy)OH2]2+ (tpy=2,2':6',2''-terpyridine, dcbpy=5,5'-dicarboxy-2,2'-bipyridine) on conducting surfaces and their propensity for electrochemical water oxidation. The electrocatalyst oxidized water with a turnover frequency (TOF) of (0.2±0.1) s-1 at 1.71 V versus the normal hydrogen electrode (NHE) in buffered solution (pH~7) and exhibited structural and electrochemical stability. The electroactive sites were distributed throughout the MOF thin film on the basis of scan-ratedependent voltammetry studies. This work demonstrates a promising way to immobilize large concentrations of electroactive WOCs into a highly robust MOF scaffold and paves the way for future photoelectrochemical water-splitting systems.

  17. Influência da adição de plastificante do processo de reticulação na morfologia, absorção de aguá e propriedades mecânicas de filmes de alginato de sódio Influence of plasticizer addition and crosslinking process on morohology, water absoption and mechanical properties of sodium alginate films

    Directory of Open Access Journals (Sweden)

    Aline Margarete Furuyama Lima

    2007-08-01

    Full Text Available The effects of sorbitol and formaldehyde on the morphology, water absorption and mechanical properties of sodium alginate films were analyzed. The morphology of the films indicated the presence of small aggregates in the surface of uncrosslinked films, which disappeared with the crosslinking process. The water uptake and percentage of elongation increased with the addition of sorbitol in uncrosslinked films. At the same time, a decrease in tensile strength and Young's modulus occurred. The swelling ratio and water uptake of crosslinked alginate/sorbitol films decreased with an increase in sorbitol content suggesting an enhanced crosslinking density due to the presence of plasticizer.

  18. Characterization of film surface treated with ECR plasma by Doppler broadening

    CERN Document Server

    Nishijima, S; Hirata, K; Kobayashi, Y; Honda, Y; Tagawa, S

    2000-01-01

    Doppler broadened positron annihilation measurements were carried out using the positron beam technique on plasma treated polyethylene films as a function of incident positron energy. In addition, surface properties of the treated films also have been measured using other conventional techniques such as FT-IR, SEM and AFM. The surface tension of the films was also determined using sessile drop method. The S-parameter is seen to decrease on the surface upon plasma treatment that introduces polar groups such as hydroxyl and carbonyl on the surface. The results are discussed.

  19. Fermi surface and quantum well states of V(110) films on W(110)

    Energy Technology Data Exchange (ETDEWEB)

    Krupin, Oleg [MS 6-2100, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Rotenberg, Eli [MS 6-2100, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kevan, S D [Department of Physics, University of Oregon, Eugene, OR 97403 (United States)

    2007-09-05

    Using angle-resolved photoemission spectroscopy, we have measured the Fermi surface of V(110) films epitaxially grown on a W(110) substrate. We compare our results for thicker films to existing calculations and measurements for bulk vanadium and find generally very good agreement. For thinner films, we observe and analyse a diverse array of quantum well states that split and distort the Fermi surface segments. We have searched unsuccessfully for a thickness-induced topological transition associated with contact between the zone-centre jungle gym and zone-boundary hole ellipsoid Fermi surface segments. We also find no evidence for ferromagnetic splitting of any bands on this surface.

  20. Langmuir and Langmuir-Blodgett films of capsules of haemoglobin at air/water and solid/air interfaces

    Indian Academy of Sciences (India)

    J Maheshkumar; A Dhathathreyan

    2013-03-01

    Organized assemblies of capsules of haemoglobin (Hb), in the size range of 0.1 to 0.3 in Langmuir films have been studied at air/water interface below and above the isoelectric point. Spread films of these organizates suggest that there is no expulsion of individual particles or particle assemblies at the interface and the particles are stable. Dynamic surface tension and the associated dilational and shear visco-elasticity in these films suggest that the capsules are highly elastic. Multilayer films of the capsules using Langmuir-Blodgett technique have been fabricated by sequential deposition on solid surfaces. These films have been characterized by circular dichroism spectroscopy (CD), atomic force microscopy (AFM), quartz crystal microbalance (QCM) and Fourier transform infrared with reflection absorption spectroscopy (FTIR-RAS). No appreciable change in the secondary structural features of Hb is seen from CD studies indicating the stability of the protein in these organized assemblies. Sizes of these capsules change near the isoelectric point and large swollen multiwalled capsules are formed. The elastic films of capsules of Hb provide a useful post preparation approach for modification of the surface roughness, porosity, and permeability of pre-assembled polypeptide microcapsules.

  1. Molecular Water Lilies: Orienting Single Molecules in a Polymer Film by Solvent Vapor Annealing

    CERN Document Server

    Wuersch, Dominik; Eder, Theresa; Aggarwal, A Vikas; Idelson, Alissa; Hoeger, Sigurd; Lupton, John M; Vogelsang, Jan

    2016-01-01

    The microscopic orientation and position of photoactive molecules is crucial to the operation of optoelectronic devices such as OLEDs and solar cells. Here, we introduce a shape-persistent macrocyclic molecule as an excellent fluorescent probe to simply measure (i) its orientation by rotating the excitation polarization and recording the strength of modulation in photoluminescence (PL), and (ii) its position in a film by analyzing the overall PL brightness at the molecular level. The unique shape, the absorption and the fluorescence properties of this probe yields information on molecular orientation and position. We control orientation and positioning of the probe in a polymer film by solvent vapor annealing (SVA). During the SVA process the molecules accumulate at the polymer/air interface, where they adopt a flat conformation, much like water lilies on the surface of a pond. The results are significant for OLED fabrication and single-molecule spectroscopy (SMS) in general.

  2. Cholesterol monohydrate nucleation in ultrathin films on water

    DEFF Research Database (Denmark)

    Rapaport, H.; Kuzmenko, I.; Lafont, S.

    2001-01-01

    The growth of a cholesterol crystalline phase, three molecular layers thick at the air-water interface, was monitored by grazing incidence x-ray diffraction and x-ray reflectivity. Upon compression, a cholesterol film transforms from a monolayer of trigonal symmetry and low crystallinity...... to a trilayer, composed of a highly crystalline bilayer in a rectangular lattice and a disordered top cholesterol layer. This system undergoes a phase transition into a crystalline trilayer incorporating ordered water between the hydroxyl groups of the top and middle sterol layers in an arrangement akin...... to the triclinic 3-D crystal structure of cholesterol . H(2)O. By comparison, the cholesterol derivative stigmasterol transforms, upon compression, directly into a crystalline trilayer in the rectangular lattice. These results may contribute to an understanding of the onset of cholesterol crystallization...

  3. Nitrate reducing activity pervades surface waters during upwelling.

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, S.O.; Halarnekar, R.; Malik, A.; Vijayan, V.; Varik, S.; RituKumari; Jineesh V.K.; Gauns, M.U.; Nair, S.; LokaBharathi, P.A.

    Nitrate reducing activity (NRA) is known to be mediated by microaerophilic to anaerobic bacteria and generally occurs in the sub-surface waters. However, we hypothesize that NRA could become prominent in the surface waters during upwelling. Hence...

  4. Enhanced water vapor barrier properties for biopolymer films by polyelectrolyte multilayer and atomic layer deposited Al{sub 2}O{sub 3} double-coating

    Energy Technology Data Exchange (ETDEWEB)

    Hirvikorpi, Terhi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Vaehae-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Harlin, Ali [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Salomaeki, Mikko [University of Turku, Department of Chemistry, Laboratory of Materials Chemistry and Chemical Analysis, Vatselankatu 2, FI-20014 (Finland); Areva, Sami [Tampere University of Technology, Department of Biomedical Engineering, Biokatu 6, P.O. Box 692, FI-33101 Tampere (Finland); Korhonen, Juuso T. [Aalto University School of Science, Department of Applied Physics, P.O. Box 15100 FI-00076 AALTO, Espoo (Finland); Karppinen, Maarit [Aalto University School of Chemical Technology, Laboratory of Inorganic Chemistry, P.O. Box 16100, FI-00076 AALTO, Espoo (Finland)

    2011-09-01

    Commercial polylactide (PLA) films are coated with a thin (20 nm) non-toxic polyelectrolyte multilayer (PEM) film made from sodium alginate and chitosan and additionally with a 25-nm thick atomic layer deposited (ALD) Al{sub 2}O{sub 3} layer. The double-coating of PEM + Al{sub 2}O{sub 3} is found to significantly enhance the water vapor barrier properties of the PLA film. The improvement is essentially larger compared with the case the PLA film being just coated with an ALD-grown Al{sub 2}O{sub 3} layer. The enhanced water vapor barrier characteristics of the PEM + Al{sub 2}O{sub 3} double-coated PLA films are attributed to the increased hydrophobicity of the surface of these films.

  5. Optical field-induced surface relief formation on chalcogenide and azo-benzene polymer films

    Science.gov (United States)

    Teteris, J.; Gertners, U.

    2012-08-01

    The dependence of the surface relief formation in amorphous As2S3 and Disperse Red 1dye grafted polyurethane polymer films on the polarization state of recording light was studied. It is shown that the direction of mass transport on the film surface is determined by the direction of light electric vector and photoinduced anisotropy in the film. We propose a photoinduced dielectropfhoretic model to explain the photoinduced mass transport in amorphous films. Model is based on the photoinduced softening of the matrix, formation of defects with enhanced or decreased polarizability, and their drift under the electrical field gradient of light.

  6. Corrosion control of aluminum surfaces by polypyrrole films: influence of electrolyte

    Directory of Open Access Journals (Sweden)

    Andréa Santos Liu

    2007-06-01

    Full Text Available Polypyrrole (PPy films were galvanostatically deposited on 99.9 wt. (% aluminum electrodes from aqueous solutions containing each carboxylic acid: tartaric, oxalic or citric. Scanning Electron Microscopy (SEM was used to analyze the morphology of the aluminum surfaces coated with the polymeric films. It was observed that the films deposited from tartaric acid medium presented higher homogeneity than those deposited from oxalic and citric acid. Furthermore, the corrosion protection of aluminum surfaces by PPy films was also investigated by potentiodynamic polarization experiments.

  7. Atomic Force Microscopy Studies on The Surface Morphologies of Chemical Bath Deposited Cus Thin Films

    Directory of Open Access Journals (Sweden)

    Ho Soonmin

    2016-06-01

    Full Text Available In this work, copper sulphide thin films were deposited onto microscope glass slide by chemical bath deposition technique. The tartaric acid was served as complexing agent to chelate with Cu2+ to obtain complex solution. The influence of pH value on the surface morphologies of the films has been particularly investigated using the atomic force microscopy technique. The atomic force microscopy results indicate that the CuS films deposited at pH 1 were uniform, compact and pinhole free. However, the incomplete surface coverage observed for the films prepared at high pH (pH 2 and 2.5 values.

  8. Let's Talk About Water: Film Screenings as an Entrée to Water Science

    Science.gov (United States)

    Hooper, R. P.; Lilienfeld, L.; Arrigo, J.

    2011-12-01

    "Let's Talk about Water" is a film symposium designed to bring together experts and the public to talk about the complex water issues facing society. The format of the event is quite simple: a panel of experts and the audience view a water documentary (such as "FLOW", "Liquid Assets", or "Gasland") together and there is an extended moderated discussion period following the film between the panel and the audience. Properly handled, this simple format can be very effective. A film creates a context of subject and language for the discussion--it gets the audience and the panel on the same page. The moderators must actively manage the discussion, both challenging the panelists with follow up questions, asking questions to simplify the language the expert is using, and passing a question among panelists to bring out different points of view. The panelists are provided with the film in advance to view and, most importantly, meet the day before the event to discuss the film. This makes for a much more convivial discussion at the event. We have found that these discussions can easily be sustained for 90 to 120 minutes with active audience participation. This format has been applied at college campuses with a target audience of lower-level undergraduates. Student clubs are engaged to help with publicity before the event and to assist with registration and ushering during the event. Appropriate classes offer extra credit for student attendance to ensure a strong turnout. A Hollywood film ("Chinatown" in southern California, "A Civil Action" in Boston) is shown on campus during the week preceding the event to help advertise the event. The event itself is typically held on a Saturday with a morning screening of the film. The audience is provided with index cards and pencils to write down questions they have about the film. A lunch is provided during which the questions are organized and used to initiate different discussion themes. The discussion begins with points raised by

  9. Synthesis of antibacterial film CTS/PVP/TiO2/Ag for drinking water system.

    Science.gov (United States)

    Zhang, Liang; Bai, Xue; Tian, Hua; Zhong, Lvling; Ma, Cailian; Zhou, Yuanzhen; Chen, Shuangli; Li, Dongliang

    2012-08-01

    A CTS/PVP/TiO2/Ag functional film was prepared as an antibacterial composite used in storing drinking water. The orthogonal experiment showed that the optimal conditions for preparing membranes with best antibacterial activity and tensile strength are c(AgNO3)=0.08%, c(TiO2)=0.20%, c(CTS)=2.25%, and c(PVP)=3.00%. The FT-IR spectrum implies that hydrogen bands are formed between acetyl in PVP and hydroxyl in CTS molecule, and -NH and -OH of CTS have some interactions with sliver nano-particles (nano-Ags) which were reduced in situ. The SEM images show that the TiO2 particles are displayed on the surface and embedded in the film. And nano-Ags are further proved through XRD and SEM images. The DSC curves show that the film has a favorable compatibility and heat stability. In application study, it is proved that this film has sustainable antibacterial activity and is safe in use.

  10. Ion-beam modifications of the surface morphology and conductivity in some polymer thin films

    Indian Academy of Sciences (India)

    M Ramakrishna Murthy; E Venkateshwar Rao

    2002-10-01

    Studies on the surface micromorphology and surface conductivity in thin polymer films of poly vinyl alcohol (PVA) and poly ethylene oxide (PEO) in both as-grown and ion-implanted polymer films have been carried out to reveal certain specific features of the ordered state in these materials. Optical microscopic investigations revealed the existence and enhanced formation in number of spherulites and dendrites in ionimplanted films relative to the as-grown films. The number and rate of formation of spherulites indicated an increase in the degree of crystallinity in these films. Measurements of surface conductivity of as-grown and ion-implanted polymer films, employing four-point probe method, indicated a decrease in electrical conductivity on ion-implantation. Photomicrographic analysis of the PVA and PEO thin film surfaces, has enabled to propose a temperature–stress induced mechanism of crystallization in conjunction with the surface conductivity measurements. The decrease in surface conductivity on ion-implantation in both PVA and PEO thin films, is attributed to a decrease in mobility of macromolecular charged species due to an increase in degree of crystallinity as has been observed by optical microscopy.

  11. Enhancement of Water Evaporation on Solid Surfaces with Nanoscale Hydrophobic-Hydrophilic Patterns.

    Science.gov (United States)

    Wan, Rongzheng; Wang, Chunlei; Lei, Xiaoling; Zhou, Guoquan; Fang, Haiping

    2015-11-06

    Using molecular dynamics simulations, we show that the evaporation of nanoscale water on hydrophobic-hydrophilic patterned surfaces is unexpectedly faster than that on any surfaces with uniform wettability. The key to this phenomenon is that, on the patterned surface, the evaporation rate from the hydrophilic region only slightly decreases due to the correspondingly increased water thickness; meanwhile, a considerable number of water molecules evaporate from the hydrophobic region despite the lack of water film. Most of the evaporated water from the hydrophobic region originates from the hydrophilic region by diffusing across the contact lines. Further analysis shows that the evaporation rate from the hydrophobic region is approximately proportional to the total length of the contact lines.

  12. Surface Functionalization of Thin-Film Composite Membranes with Copper Nanoparticles for Antimicrobial Surface Properties

    KAUST Repository

    Ben-Sasson, Moshe

    2014-01-07

    Biofouling is a major operational challenge in reverse osmosis (RO) desalination, motivating a search for improved biofouling control strategies. Copper, long known for its antibacterial activity and relatively low cost, is an attractive potential biocidal agent. In this paper, we present a method for loading copper nanoparticles (Cu-NPs) on the surface of a thin-film composite (TFC) polyamide RO membrane. Cu-NPs were synthesized using polyethyleneimine (PEI) as a capping agent, resulting in particles with an average radius of 34 nm and a copper content between 39 and 49 wt.%. The positive charge of the Cu-NPs imparted by the PEI allowed a simple electrostatic functionalization of the negatively charged RO membrane. We confirmed functionalization and irreversible binding of the Cu-NPs to the membrane surface with SEM and XPS after exposing the membrane to bath sonication. We also demonstrated that Cu-NP functionalization can be repeated after the Cu-NPs dissolve from the membrane surface. The Cu-NP functionalization had minimal impact on the intrinsic membrane transport parameters. Surface hydrophilicity and surface roughness were also maintained, and the membrane surface charge became positive after functionalization. The functionalized membrane exhibited significant antibacterial activity, leading to an 80-95% reduction in the number of attached live bacteria for three different model bacterial strains. Challenges associated with this functionalization method and its implementation in RO desalination are discussed. © 2013 American Chemical Society.

  13. Formation and tribology properties of polyfluoroal-kylmethacrylate film on the magnetic head surface

    Institute of Scientific and Technical Information of China (English)

    HU Xiaoli; ZHANG Chenhui; LUO Jianbin; WEN Shizhu

    2005-01-01

    A polyfluoroalkylmethacrylate (PFAM) film has been coated on the surface of the magnetic head by a dipping coating method to modify the surface properties. The films were characterized by means of a time-of-flight secondary ion mass spectrometer (TOF-SIMS), contact angle measurement and atomic force microscopy (AFM). The results indicate that the concentration of the solution is the main factor affecting the thickness, contact angle and surface topography of the film. The magnetic head with the PFAM film at a concentration of 500 ppm exhibits the best tribology properties, and the stiction between the magnetic head and the disk is no more than 2.4 g after 20000 contact start stop (CSS) cycles. Therefore, a fully covered PFAM film with few defects helps improve the tribology properties of the magnetic head, and decrease the adsorbed contaminant on the magnetic head surface.

  14. Resistance of cyanobacterial fouling on architectural paint films to cleaning by water jet.

    Science.gov (United States)

    Shirakawa, Marcia Aiko; Loh, Kai; John, Vanderley Moacir; Gaylarde, Christine Claire

    2012-04-01

    Mortar panels painted with three different white acrylic coatings were exposed to the environment in urban (São Paulo) and rural (Pirassununga) sites in Brazil for 7 years. After this time, all panels were almost equally discoloured, and paint detachment was observed to only a small degree. The biofilms were composed mainly of cyanobacteria and filamentous fungi, principal genera being Gloeocapsa and Chroococcidiopsis of the cyanobacteria, and Cladosporium and Alternaria of the fungi. Two of the three paints in Pirassununga became covered by a pink film that contained red-encapsulated Gloeocapsa and clay particles. The third, an 800% elastomeric matt formulation, became discoloured with a grey, only slightly pink, film, although the same cyanobacteria were present. The levels of paint detachments from all films in both locations were low, with rating range of 0-1 of a maximum 5 (100% detachment). After high-pressure water jetting, paint detachments increased at both locations, up to 2 in Pirassununga and 3 in São Paulo. Discoloration decreased; L*A*B* analysis of surface discoloration showed that ΔE (alteration in colour from the original paint film) changed from 28-39 before cleaning to 13-16 afterwards. The pink coloration was not entirely removed from Pirassununga samples, suggesting that cyanobacterial cells are difficult to detach, and microscopic analysis of the biofilms confirmed that Gloeocapsa was still present as the principal contaminant on all surfaces, with Chroococcidiopsis being present as the second most common. Almost no fungi were detected after water jet application.

  15. Surface reactivity and layer analysis of chemisorbed reaction films in the surface-chemical environment of alkyl octadecenoates

    Indian Academy of Sciences (India)

    R B Choudhary; O N Anand; O S Tyagi

    2009-05-01

    Studies on surface reactivity of substrate iron (Fe-particles) were made in the tribo-chemical environment of alkyl octadecenoates. Two alkyl octadecenoates namely ethyl octadecenoate and methyl 12-hydroxy octadecenoate, slightly different in their chemical nature, were taken for preparing the chemisorbed reaction films (CRF) at the temperature 100 ± 5°C. The reaction products collected in the composite (amorphous) phase were isolated into three different solvent-soluble fractions (sub-layer films) using polar solvents of increasing polar strength. The FTIR analysis of these films showed that these were primarily organic in nature and were composed of alkyl and/or aryl hydroxy ethers, unsaturated hydroxy ketones, and aromatic structures chemically linked with iron surface. These reaction films also contained large amount of iron (Fe). Further, these film fractions also showed varying thermal behaviour during thermal decomposition in the temperature range of 50-800°C when thermally evaluated in the nitrogen environment.

  16. Enhanced mechanical properties of low-surface energy thin films by simultaneous plasma polymerization of fluorine and epoxy containing polymers