Science.gov

Sample records for organic surface coatings

  1. Process for Non-Contact Removal of Organic Coatings from the Surface of Paintings

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Rutledge, Sharon K. (Inventor)

    1996-01-01

    The present invention discloses a method of removing organic protective coatings from a painting. In the present invention degraded protective coatings such as lacquers, acrylics, natural resins, carbons, soot, and polyurethane are safely removed from the surface of a painting without contact to the surface of the painting. This method can be used for restoration of paintings when they have been damaged, through age, fire, etc.

  2. Process for non-contact removal of organic coatings from the surface of paintings

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Rutledge, Sharon K. (Inventor)

    1995-01-01

    The present invention discloses a method of removing organic protective coatings from a painting. In the present invention degraded protective coatings such as lacquers, acrylics, natural resins, carbons, soot, and polyurethane are safely removed from the surface of a painting without contact to the surface of the painting. This method can be used for restoration of paintings when they have been damaged, through age, fire, etc.

  3. 40 CFR 63.5752 - How do I calculate the organic HAP content of aluminum recreational boat surface coatings?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... content of aluminum recreational boat surface coatings? 63.5752 Section 63.5752 Protection of Environment... Pollutants for Boat Manufacturing Standards for Aluminum Recreational Boat Surface Coating Operations § 63.5752 How do I calculate the organic HAP content of aluminum recreational boat surface coatings? (a)...

  4. 40 CFR 63.5752 - How do I calculate the organic HAP content of aluminum recreational boat surface coatings?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... content of aluminum recreational boat surface coatings? 63.5752 Section 63.5752 Protection of Environment... Pollutants for Boat Manufacturing Standards for Aluminum Recreational Boat Surface Coating Operations § 63.5752 How do I calculate the organic HAP content of aluminum recreational boat surface coatings? (a)...

  5. Influence of organic surface coatings on the sorption of anticonvulsants on mineral surfaces.

    PubMed

    Qu, Shen; Cwiertny, David M

    2013-10-01

    Here, we explore the role that sorption to mineral surfaces plays in the fate of two commonly encountered effluent-derived pharmaceuticals, the anticonvulsants phenytoin and carbamazepine. Adsorption isotherms and pH-edge experiments are consistent with electrostatics governing anticonvulsant uptake on metal oxides typically found in soil and aquifer material (e.g., Si, Al, Fe, Mn, and Ti). Appreciable, albeit limited, adsorption was observed only for phenytoin, which is anionic above pH 8.3, on the iron oxides hematite and ferrihydrite. Adsorption increased substantially in the presence of cationic and anionic surfactants, species also commonly encountered in wastewater effluent. For carbamazepine, we propose the enhanced uptake results entirely from hydrophobic interactions with apolar tails of surfactant surface coatings. For phenytoin, adsorption also arises from the ability of surfactants to alter the net charge of the mineral surface and thereby further enhance favorable electrostatic interactions with its anionic form. Collectively, our results demonstrate that although pristine mineral surfaces are likely not major sinks for phenytoin and carbamazepine in the environment, their alteration with organic matter, particularly surfactants, can considerably increase their ability to retain these emerging pollutants in subsurface systems. PMID:24084847

  6. Atomic Oxygen Treatment for Non-Contact Removal of Organic Protective Coatings from Painting Surfaces

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Banks, Bruce A.; Cales, Michael

    1994-01-01

    Current techniques for removal of varnish (lacquer) and other organic protective coatings from paintings involve contact with the surface. This contact can remove pigment, or alter the shape and location of paint on the canvas surface. A thermal energy atomic oxygen plasma, developed to simulate the space environment in low Earth orbit, easily removes these organic materials. Uniform removal of organic protective coatings from the surfaces of paintings is accomplished through chemical reaction. Atomic oxygen will not react with oxides so that most paint pigments will not be affected by the reaction. For paintings containing organic pigments, the exposure can be carefully timed so that the removal stops just short of the pigment. Color samples of Alizarin Crimson, Sap Green, and Zinc White coated with Damar lacquer were exposed to atomic oxygen. The lacquer was easily removed from all of the samples. Additionally, no noticeable change in appearance was observed after the lacquer was reapplied. The same observations were made on a painted canvas test sample obtained from the Cleveland Museum of Art. Scanning electron microscope photographs showed a slight microscopic texturing of the vehicle after exposure. However, there was no removal or disturbance of the paint pigment on the surface. It appears that noncontact cleaning using atomic oxygen may provide a viable alternative to other cleaning techniques. It is especially attractive in cases where the organic protective surface cannot be acceptably or safely removed by conventional techniques.

  7. Surface-enhanced Raman spectroscopy (SERS) to detect natural organic coatings on silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Kühn, Melanie; Ivleva, Natalia P.; Klitzke, Sondra; von der Kammer, Frank; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    Applications for engineered inorganic nanoparticles (EINP) are rising and causing a higher risk for EINP to be released into the environment. Their stability and transport behaviour under environmental conditions is strongly depending on their surface properties which on the other hand depend on the presence or absence of a surface coating. We assume that EINP get coated soon after their release into the environment e.g. by humic substances like humic or fulvic acids and NOM. Often EINP are stabilized by a coating agent like citrate or polyvinylpyrrolidone. Therefore, the replacement of the initial coating material or a multilayer coating has to be considered. Characterization of natural coatings on EINP is crucial to predict their environmental behaviour, but analytical methods to investigate organic coatings are scarce. To investigate humic- and fulvic acid coatings on silver nanoparticles (Ag NP) Raman micro-spectroscopy (RM) was used. RM is limited in its sensitivity, but silver nanoparticles cause an enhancement of the Raman signal of adsorbed substances by a factor of 103-106, so called surface-enhanced Raman spectroscopy (SERS). The Raman spectrum of humic acids is dominated by the carbonaceous parts of the humic acids which are known from carbon analysis and referred to as defect (D) and graphite (G) peak of carbon. Humic acids of different origin (humic acid from a lignite, suwannee river humic acid) showed differences in the D and G ratios indicating a difference in the structure of the contained carbon. With SERS humic and fulvic acid coatings on Ag NP were analysed: 1-100 mg/L humic acid stock solution were mixed with citrate and hydroxylammoniumchloride stabilized Ag NP, centrifuged and resuspended in deionized water (washing) to remove all coating material not associated with Ag NP. This washing step was repeated up to four times. SERS prooved that the coating was still present after the fourth washing step. As SERS is only sensitive for substances in

  8. Production of Organic Grain Coatings by Surface-Mediated Reactions and the Consequences of This Process for Meteoritic Constituents

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A., III; Johnson, Natasha M.

    2011-01-01

    When hydrogen, nitrogen and CO are exposed to amorphous iron silicate surfaces at temperatures between 500 - 900K, a carbonaceous coating forms via Fischer-Tropsch type reactions. Under normal circumstances such a catalytic coating would impede or stop further reaction. However, we find that this coating is a better catalyst than the amorphous iron silicates that initiate these reactions. The formation of a self-perpetuating catalytic coating on grain surfaces could explain the rich deposits of macromolecular carbon found in primitive meteorites and would imply that protostellar nebulae should be rich in organic material. Many more experiments are needed to understand this chemical system and its application to protostellar nebulae.

  9. Flow accelerated organic coating degradation

    NASA Astrophysics Data System (ADS)

    Zhou, Qixin

    Applying organic coatings is a common and the most cost effective way to protect metallic objects and structures from corrosion. Water entry into coating-metal interface is usually the main cause for the deterioration of organic coatings, which leads to coating delamination and underfilm corrosion. Recently, flowing fluids over sample surface have received attention due to their capability to accelerate material degradation. A plethora of works has focused on the flow induced metal corrosion, while few studies have investigated the flow accelerated organic coating degradation. Flowing fluids above coating surface affect corrosion by enhancing the water transport and abrading the surface due to fluid shear. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a pigmented marine coating and several clear coatings were exposed to the laminar flow and stationary immersion. The laminar flow was pressure driven and confined in a flow channel. A 3.5 wt% sodium chloride solution and pure water was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The working fluids were characterized by Fourier Transform Infrared Spectrometer (FTIR) and conductivity measurement. The influence of flow rate, fluid shear, fluid composition, and other effects in the coating degradation were investigated. We conclude that flowing fluid on the coating surface accelerates the transport of water, oxygen, and ions into the coating, as

  10. Surface binding of polymer coated nanoparticles: Coupling of physical interactions, molecular organization, and chemical state

    NASA Astrophysics Data System (ADS)

    Nap, Rikkert; Szleifer, Igal

    2014-03-01

    A key challenge in nanomedicine is to design carrier system for drug delivery that selectively binds to target cells without binding to healthy cells. A common strategy is to end-functionalize the polymers coating of the delivery device with specific ligands that bind strongly to overexpressed receptors. Such devices are usually unable to discriminate between receptors found on benign and malignant cells. We demonstrate, theoretically, how one can achieve selective binding to target cells by using multiple physical and chemical interactions. We study the effective interactions between a polymer decorated nanosized micelle or solid nanoparticle with model lipid layers. The polymer coating contains a mixture of two polymers, one neutral for protection and the other a polybase with a functional end-group to optimize specific binding and electrostatic interactions with the charged lipid head-groups found on the lipid surface. The strength of the binding for the combined system is much larger than the sum of the independent electrostatic or specific ligand-receptor binding. The search for optimal binding conditions lead to the finding of a non-additive coupling that exists in systems where chemical equilibrium, molecular organization, and physical interactions are coupled together.

  11. Final Technical Report: Mercury Release from Organic Matter (OM) and OM-Coated Mineral Surfaces

    SciTech Connect

    Nagy, Kathryn L.

    2015-08-18

    Chemical reactions between mercury, a neurotoxin, and sulfur, an essential nutrient, in the environment control to a large extent the distribution and amount of mercury available for uptake by living organisms. The largest reservoir of sulfur in soils is in living, decaying, and dissolved natural organic matter. The decaying and dissolved organic matter can also coat the surfaces of minerals in the soil. Mercury (as a divalent cation) can bind to the sulfur species in the organic matter as well as to the bare mineral surfaces, but the extent of binding and release of this mercury is not well understood. The goals of the research were to investigate fundamental relationships among mercury, natural organic matter, and selected minerals to better understand specifically the fate and transport of mercury in contaminated soils downstream from the Y-12 plant along East Fork Poplar Creek, Tennessee, and more generally in any contaminated soil. The research focused on (1) experiments to quantify the uptake and release of mercury from two clay minerals in the soil, kaolinite and vermiculite, in the presence and absence of dissolved organic matter; (2) release of mercury from cinnabar under oxic and anoxic conditions; (3) characterization of the forms of mercury in the soil using synchrotron X-ray absorption spectroscopic techniques; and, (4) determination of molecular forms of mercury in the presence of natural organic matter. We also leveraged funding from the National Science Foundation to (5) evaluate published approaches for determining sulfur speciation in natural organic matter by fitting X-ray Absorption Near Edge Structure (XANES) spectra obtained at the sulfur K-edge and apply optimized fitting schemes to new measurements of sulfur speciation in a suite of dissolved organic matter samples from the International Humic Substances Society. Lastly, in collaboration with researchers at the University of Colorado and the U.S. Geological Survey in Boulder, Colorado, (6

  12. Contact angle anomalies indicate that surface-active eluates from silicone coatings inhibit the adhesive mechanisms of fouling organisms.

    PubMed

    Meyer, Anne; Baier, Robert; Wood, Christina Darkangelo; Stein, Judith; Truby, Kathryn; Holm, Eric; Montemarano, Jean; Kavanagh, Christopher; Nedved, Brian; Smith, Celia; Swain, Geoff; Wiebe, Deborah

    2006-01-01

    Silicone coatings with critical surface tensions (CST) between 20 and 30 mN m-1 more easily release diverse types of biofouling than do materials of higher and lower CST. Oils added to these coatings selectively further diminish the attachment strengths of different marine fouling organisms, without significantly modifying the initial CST. In a search for the mechanisms of this improved biofouling resistance, the interfacial instabilities of four silicone coatings were characterised by comprehensive contact angle analyses, using up to 12 different diagnostic fluids selected to mimic the side chain chemistries of the common amino acids of bioadhesive proteins. The surfaces of painted steel test panels were characterised both before and after exposure to freshwater, brackish water, and seawater over periods ranging from 9 months to nearly 4 years. Contact angle measurements demonstrated significant surface activity of the oil-amended coatings both before and after long-term underwater exposure. The surface activity of the control (coating without oil) increased as a result of underwater exposure, consistent with mild surface chain scission and hydrolysis imparting a self-surfactancy to the coating and providing a weak boundary layer promoting continuing easy release of attaching foulants. Coatings with additives that most effectively reduced biofouling showed both initial and persistent contact angle anomalies for the test liquid, thiodiglycol, suggesting lower-shear biofouling release mechanisms based upon diminished bioadhesive crosslinking by interfering with hydrogen- and sulfhydryl bonds. Swelling of the silicone elastomeric coatings by hydrocarbon fluids was observed for all four coatings, before and after immersion. PMID:17178574

  13. Molecular modeling of interactions between heavy crude oil and the soil organic matter coated quartz surface.

    PubMed

    Wu, Guozhong; Zhu, Xinzhe; Ji, Haoqing; Chen, Daoyi

    2015-01-01

    Molecular dynamic (MD) simulation was applied to evaluate the mobility, diffusivity and partitioning of SARA (saturates, aromatics, resins, asphaltenes) fractions of heavy crude oil on soil organic matter (SOM) coated quartz surface. Four types of SOM were investigated including Leonardite humic acid, Temple-Northeastern-Birmingham humic acid, Chelsea soil humic acid and Suwannee river fulvic acid. The SOM aggregation at oil-quartz interface decreased the adsorption of SARA on the quartz surface by 13-83%. Although the SOM tended to promote asphaltenes aggregation, the overall mobility of SARA was significantly greater on SOM-quartz complex than on pure quartz. Particularly, the diffusion coefficient of asphaltenes and resins increased by up to one-order of magnitude after SOM addition. The SOM increased the overall oil adsorption capacity but also mobilized SARA by driving them from the viscous oil phase and rigid quartz to the elastic SOM. This highlighted the potential of SOM addition for increasing the bioavailability of heavy crude oil without necessarily increasing the environmental risks. The MD simulation was demonstrated to be helpful for interpreting the role of SOM and the host oil phase for the adsorption and partitioning of SARA molecules, which is the key for developing more realistic remediation appraisal for heavy crude oil in soils. PMID:25016557

  14. Reverse switching of surface roughness in a self-organized polydomain liquid crystal coating

    PubMed Central

    Liu, Danqing; Liu, Ling; Onck, Patrick R.; Broer, Dirk J.

    2015-01-01

    In this work we propose randomly ordered polydomain nematic liquid crystal polymer networks to reversibly generate notable jagged relief patterns at a polymer coating surface by light illumination. The domain size is controlled by the addition of traces of partly insoluble fluorinated acrylate. The photoresponse of the coating is induced by a small amount of copolymerized azobenzene monomers. Upon exposure to UV light, azobenzene undergoes trans to cis isomerization, resulting in a change in molecular order and packing within each domain. The extent of this effect and its directionality depends on the domain orientation. Localized to domain level, this morphological change forms large 3D spikes at the surface with a modulation amplitude of more than 20% of the initial thickness. The process is reversible; the surface topographical patterns erase within 10 s by stopping the light exposure. A finite element model is applied to simulate the surface topography changes of the polydomain coating. The simulations describe the formation of the topographic features in terms of light absorption and isomerization process as a function of the director orientation. The random director distribution leads to surface structures which were found to be in close agreement with the ones measured by interference microscopy. The effect of domain size on surface roughness and depth modulation was explored and related to the internal mechanical constraints. The use of nematic liquid crystal polydomains confined in a polymer network largely simplifies the fabrication of smart coatings with a prominent triggered topographic response. PMID:25775559

  15. 40 CFR 63.5752 - How do I calculate the organic HAP content of aluminum recreational boat surface coatings?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., top coat, or clear coat i used in the past 12 months, liters. Di = density of coating i, kilograms per... = density of thinner, activator, or additive k, kilograms per liter. Wk = mass fraction of organic HAP...

  16. Cytotoxicity of Organic Surface Coating Agents Used for Nanoparticles Synthesis and Stability

    PubMed Central

    Zhang, Ying; Newton, Brandon; Lewis, Eybriunna; Fu, Peter P.; Kafoury, Ramzi; Ray, Paresh C.; Yu, Hongtao

    2015-01-01

    Impact on health by nanomaterials has become a public concern with the great advances of nanomaterials for various applications. Surface coating agents are an integral part of nanoparticles, but not enough attention has been paid during toxicity tests of nanoparticles. As a result, there are inconsistent toxicity results for certain nanomaterials. In this study, we explore the cytotoxicity of eleven commonly used surface coating agents in two cell lines, human epidermal keratinocyte (HaCaT) and lung fibroblast (CRL-1490) cells, at surface coating agent concentrations of 3, 10, 30, and 100 μM. Two exposure time points, 2 h and 24 h, were employed for the study. Six of the eleven surface coating agents are cytotoxic, especially those surfactants with long aliphatic chains, both cationic (cetyltrimethylammonium bromide, oleylamine, tetraoctylammonium bromide, and hexadecylamine) and anionic (sodium dodecylsulfate). In addition, exposure time and the use of different cell lines also affect the cytotoxicity results. Therefore, factors such as cell lines used and exposure times must be considered when conducting toxicity tests or comparing cytotoxicity results. PMID:25746383

  17. Investigation of coatings of natural organic matter on silver nanoparticles under environmentally relevant conditions by surface-enhanced Raman scattering.

    PubMed

    Kühn, Melanie; Ivleva, Natalia P; Klitzke, Sondra; Niessner, Reinhard; Baumann, Thomas

    2015-12-01

    The widespread use of engineered inorganic nanoparticles (EINP) leads to a growing risk for an unintended release into the environment. Despite the good characterization of EINP in regard to their function scale and the application areas, there is still a gap of knowledge concerning their behaviour in the different environmental compartments. Due to their high surface to volume ratio, surface properties and existence or development of a coating are of high importance for their stability and transport behaviour. However, analytical methods to investigate organic coatings on nanoparticles in aqueous media are scarce. We used Raman microspectroscopy in combination with surface-enhanced Raman scattering (SERS) to investigate humic acid coatings on silver nanoparticles under environmentally relevant conditions and in real world samples. This setup is more challenging than previous mechanistic studies using SERS to characterize the humic acids in tailored settings where only one type of organic matter is present and the concentrations of the nanoparticles can be easily adjusted to the experimental needs. SERS offers the unique opportunity to work with little sample preparation directly with liquid samples, thus significantly reducing artefacts. SERS spectra of different natural organic matter brought into contact with silver nanoparticles indicate humic acid in close proximity to the nanoparticles. This coating was also present after several washing steps by centrifugation and resuspension in deionized water and after an increase in ionic strength. PMID:25554386

  18. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid, spray on elastomeric polyurethanes are selected and investigated as best candidates for aircraft external protective coatings. Flight tests are conducted to measure drag effects of these coatings compared to paints and a bare metal surface. The durability of two elastometric polyurethanes are assessed in airline flight service evaluations. Laboratory tests are performed to determine corrosion protection properties, compatibility with aircraft thermal anti-icing systems, the effect of coating thickness on erosion durability, and the erosion characteristics of composite leading edges-bare and coated. A cost and benefits assessment is made to determine the economic value of various coating configurations to the airlines.

  19. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A series of studies in which films and liquid spray-on materials were evaluated in the laboratory for transport aircraft external surface coatings are summarized. Elastomeric polyurethanes were found to best meet requirements. Two commercially available products, CAAPCO B-274 and Chemglaze M313, were subjected to further laboratory testing, airline service evaluations, and drag-measurement flight tests. It was found that these coatings were compatible with the severe operating environment of airlines and that coatings reduced airplane drag. An economic analysis indicated significant dollar benefits to airlines from application of the coatings.

  20. Volatile organic compounds (VOCs) in surface coating materials: Their compositions and potential as an alternative fuel.

    PubMed

    Dinh, Trieu-Vuong; Choi, In-Young; Son, Youn-Suk; Song, Kyu-Yong; Sunwoo, Young; Kim, Jo-Chun

    2016-03-01

    A sampling system was designed to determine the composition ratios of VOCs emitted from 31 surface coating materials (SCMs). Representative architectural, automotive, and marine SCMs in Korea were investigated. Toluene, ethylbenzene, and xylene were the predominant VOCs. The VOC levels (wt%) from automotive SCMs were significantly higher than those from architectural and marine paints. It was found that target SCMs comprised mainly VOCs with 6-10 carbon atoms in molecules, which could be adsorbed by activated carbon. The saturated activated carbon which had already adsorbed toluene, ethylbenzene, and m-xylene was combusted. The saturated activated carbon was more combustible than new activated carbon because it comprised inflammable VOCs. Therefore, it could be an alternative fuel when using in a "fuelization system". To use the activated carbon as a fuel, a control technology of VOCs from a coating process was also designed and introduced. PMID:26708646

  1. VIRUS ADSORPTION TO MINERAL SURFACES IS REDUCED BY MICROBIAL OVERGROWTH AND ORGANIC COATINGS

    EPA Science Inventory

    In experiments with strains of poliovirus, reovirus, echovirus and Coxsackievirus, overgrowth with exopolymer-forming bacteria reduced virus adsorption to mineral surfaces. Adsorption was improved when organic materials adsorbed to minerals were removed by low-temperature ashing....

  2. Carbon Density Is an Indicator of Mass Accommodation Coefficient of Water on Organic-Coated Water Surface.

    PubMed

    Ergin, Gözde; Takahama, Satoshi

    2016-05-12

    The condensational growth of a water droplet follows water vapor accommodation and is described by the mass accommodation coefficient, α. To determine α for droplets coated by straight chain and branched alcohols, we perform molecular dynamics simulations with umbrella sampling and direct impinging. The free energy profiles of water from gas phase to bulk water coated by organic are estimated by the former method. These free energy profiles exhibit a barrier to accommodation in the monolayers containing alcohols with zero and one-level of branching. However, the barrier is not observed for monolayers containing alcohols with two-levels of branching. These profiles and friction coefficients estimated from simulation are used to calculate α from the transition state and Grote-Hynes theory. Results are compared with sticking probabilities estimated from direct impinging simulations, and their differences are interpreted through processes included in each theory. At a low surface coverage of these surface active molecules, the underlying bulk solution is exposed and the resistance to vapor accommodation is reduced. We estimate the carbon density in water surfaces coated by straight-chain alcohols, branched alcohols, and straight-chain fatty acids used in study by Takahama and Russell,1 and show that this quantity is related monotonically to the mass accommodation coefficient. PMID:27089481

  3. Characterization of polymeric surface acoustic wave sensor coatings and semiempirical models of sensor responses to organic vapors.

    PubMed

    Patrash, S J; Zellers, E T

    1993-08-01

    Responses from an array of four polymer-coated surface acoustic wave sensors exposed to a series of 39 organic vapors were used to investigate sensor response models based on vapor boiling point, solubility parameters, and solvation parameters in conjunction with linear solvation energy relationships. As part of this effort, sensor response data were used to estimate the solubility parameters and solvation parameters of the sensor coatings by adaptation of methods originally developed for use with gas-liquid chromatographic retention data. Values of these parameters were found to be consistent with the structures of the coatings though in some cases different from those determined by other methods. Discrepancies were attributed to differences in the conditions used for the determinations. Sensor responses were linear over the concentration ranges examined and could be summarized using the empirically determined partition coefficient, Ke, for each vapor-coating pair. Linear correlations were found between log Ke and vapor boiling point, and the slopes of the regressions lines were similar to those expected for ideal behavior. The strength of the correlations decreased with increasing coating polarity, and it was necessary to divide the vapors into two or three broad chemical classes in order to obtain satisfactory results. Improved correlations were found by use of Hildebrand solubility parameters in a model based on regular solution theory which attempts to account for nonideal vapor-coating interactions. The use of solvation parameters in linear solvation energy relationships, however, provided the strongest correlations, with modeled K values falling within a factor of 2 of experimental values in all cases and within +/- 25% of experimental values in 83% of the cases. Application of these models to the prediction of sensor array response patterns appears promising. PMID:8372969

  4. Magnetic materials based on manganese zinc ferrite with surface-organized polyaniline coating

    NASA Astrophysics Data System (ADS)

    Kazantseva, N. E.; Bespyatykh, Yu. I.; Sapurina, I.; Stejskal, J.; Vilčáková, J.; Sáha, P.

    2006-06-01

    Core-shell composites of manganese-zinc (MnZn) ferrite and polyaniline (PANI) have been prepared by the oxidation of aniline with ammonium peroxydisulfate in the presence of ferrite. The various reaction conditions allowed controlling the thickness of PANI coating, 50-250 nm. Complex magnetic permeability spectra of MnZn ferrite of various particles sizes, 25-250 μm, and of their composites with PANI, have been studied in the frequency range 1 MHz-10 GHz. The formation of a polymer p-semiconducting nanolayer on the surface of a MnZn ferrite particle changes the character of the frequency dispersion of the permeability. The interfacial effects between MnZn ferrite and PANI nanofilm are responsible for the shifts of resonance frequency from MHz closer to GHz. This effect strongly depends on the specific area of the ferrite-PANI interface and, moreover, on the properties of the PANI overlayer.

  5. Friction surfaced Stellite6 coatings

    SciTech Connect

    Rao, K. Prasad; Damodaram, R.; Rafi, H. Khalid; Ram, G.D. Janaki; Reddy, G. Madhusudhan; Nagalakshmi, R.

    2012-08-15

    Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: Black-Right-Pointing-Pointer Stellite6 used as coating material for friction surfacing. Black-Right-Pointing-Pointer Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. Black-Right-Pointing-Pointer Finer and uniformly distributed carbides in friction surfaced coatings. Black-Right-Pointing-Pointer Absence of melting results compositional homogeneity in FS Stellite6 coatings.

  6. VOC PREVENTION OPTIONS FOR SURFACE COATING

    EPA Science Inventory

    The paper discusses some of the volatile organic compound (VOC) prevention options for surface coating. Most small surface coating industries are considered to be stationary area sources. Although stationary area sources may account for as much as 50% of national VOC emissions, t...

  7. Ceramic coatings on smooth surfaces

    NASA Technical Reports Server (NTRS)

    Miller, R. A. (Inventor); Brindley, W. J. (Inventor); Rouge, C. J. (Inventor)

    1991-01-01

    A metallic coating is plasma sprayed onto a smooth surface of a metal alloy substitute or on a bond coating. An initial thin ceramic layer is low pressure sprayed onto the smooth surface of the substrate or bond coating. Another ceramic layer is atmospheric plasma sprayed onto the initial ceramic layer.

  8. ORGANIC COATING REMOVAL

    EPA Science Inventory

    Cleaner coating removal technologies are developing rapidly to meet a variety of industrial needs to replace solvent strippers having toxic properties. his guide describes cleaner technologies that can be used to reduce waste in coating removal operations. nformation is presented...

  9. Corrosion inhibiting organic coatings

    SciTech Connect

    Sasson, E.

    1984-10-16

    A corrosion inhibiting coating comprises a mixture of waxes, petroleum jelly, a hardener and a solvent. In particular, a corrosion inhibiting coating comprises candelilla wax, carnauba wax, microcrystalline waxes, white petrolatum, an oleoresin, lanolin and a solvent.

  10. Protective, Sacrificial Coats On Optical Surfaces

    NASA Technical Reports Server (NTRS)

    Babel, Henry W.; Hasegawa, Mark M.; Jones, Cherie A.

    1994-01-01

    Clear, easily cleaned sacrificial coats of polytetrafluoroethylene, polyurethane, silicone, or other low-outgassing organic films help maintain optical properties of surfaces of radiators, solar panels, and other components. Contamination removed by erosion of coats. Applied by conventional spraying or other techniques. Originally coats intended to protect surfaces of radiators on spacecraft in low orbit around the Earth. On Earth, used to protect optical surfaces against damage during manufacture or protect and facilitate cleaning of optical surfaces particularly delicate or otherwise not cleaned easily.

  11. Nature Inspired Surface Coatings

    NASA Astrophysics Data System (ADS)

    Rubner, Michael

    2011-04-01

    Materials Scientists more and more are looking to nature for clues on how to create highly functional surface coatings with exceptional properties. The fog harvesting capabilities of the Namib Desert beetle, the beautiful iridescent colors of the hummingbird, and the super water repellant abilities of the Lotus leaf are but a few examples of the amazing properties developed over many years in the natural world. Nature also makes extensive use of the pH-dependent behavior of weak functional groups such as carboxylic acid and amine functional groups. This presentation will explore synthetic mimics to the nano- and microstructures responsible for these fascinating properties. For example, we have demonstrated a pH-induced porosity transition that can be used to create porous films with pore sizes that are tunable from the nanometer scale to the multiple micron scale. The pores of these films, either nano- or micropores, can be reversibly opened and closed by changes in solution pH. The ability to engineer pH-gated porosity transitions in heterostructured thin films has led to the demonstration of broadband anti-reflection coatings that mimic the anti-reflection properties of the moth eye and pH-tunable Bragg reflectors with a structure and function similar to that found in hummingbird wings and the Longhorn beetle. In addition, the highly textured honeycomb-like surfaces created by the formation of micron-scale pores are ideally suited for the creation of superhydrophobic surfaces that mimic the behavior of the self-cleaning lotus leaf. The development of synthetic "backbacks" on immune system cells that may one day ferry drugs to disease sites will also be discussed.

  12. Mechanism of formation of humus coatings on mineral surfaces 3. Composition of adsorbed organic acids from compost leachate on alumina by solid-state 13C NMR

    USGS Publications Warehouse

    Wershaw, R. L.; Llaguno, E.C.; Leenheer, J.A.

    1996-01-01

    The adsorption of compost leachate DOC on alumina is used as a model for elucidation of the mechanism of formation of natural organic coatings on hydrous metal oxide surfaces in soils and sediments. Compost leachate DOC is composed mainly of organic acid molecules. The solid-state 13C NMR spectra of these organic acids indicate that they are very similar in composition to aquatic humic substances. Changes in the solid-state 13C NMR spectra of compost leachate DOC fractions adsorbed on alumina indicate that the DOC molecules are most likely adsorbed on metal oxide surfaces through a combination of polar and hydrophobic interaction mechanisms. This combination of polar and hydrophobic mechanism leads to the formation of bilayer coatings of the leachate molecules on the oxide surfaces.

  13. Final technical report; Mercury Release from Organic matter (OM) and OM-Coated Mineral Surfaces

    SciTech Connect

    Aiken, George

    2014-10-02

    This document is the final technical report for a project designed to address fundamental processes controlling the release of mercury from flood plain soils associated with East Fork Poplar Creek, Tennessee near the U.S. Department of Energy Oak Ridge facility. The report summarizes the activities, findings, presentations, and publications resulting from an award to the U.S. Geological that were part of a larger overall effort including Kathy Nagy (University of Illinois, Chicago, Ill) and Joseph Ryan (University of Colorado, Boulder, CO). The specific charge for the U.S.G.S. portion of the study was to provide analytical support for the larger group effort (Nagy and Ryan), especially with regard to analyses of Hg and dissolved organic matter, and to provide information about the release of mercury from the floodplain soils.

  14. Sorption of nonpolar neutral organic compounds to low-surface-area metal (hydr)oxide- and humic acid- coated model aquifer sands.

    PubMed

    Joo, Jin Chul; Song, Myung-Shin; Kim, Jong-Kyu

    2012-01-01

    The roles of mineral-bound humic acid (HA) and mineral surfaces in the sorption of six nonpolar neutral organic compounds with relatively high aqueous solubility, S(w), (1,2,4-trichlorobenzene, 1,4-dichlorobenzene, chlorobenzene, m-xylene, toluene, and benzene) to low-surface-area (i.e., ≤ 1.2 m(2)/g) metal (hydr)oxide- and HA-coated sands with low organic carbon fractions (i.e., 0.006% ≤ f(oc) ≤ 0.044%) were investigated using well-characterized mineral surfaces [i.e., α-FeO(OH)- or Al(2)O(3)- coated sands], terrestrial HA, and solutions with relatively constant pH and ionic strength. Sorption isotherms of all six compounds to low-surface-area metal (hydr)oxide-and HA-coated sands were practically linear (i.e., 0.898 ≤ n ≤ 1.06), and resulted from a combination of sorption to both mineral-bound HA and mineral surfaces, with the dominance of either contribution depending on the properties of the sorbents (e.g., f(oc)) and organic compounds (e.g., S(w) and K(ow)). Compared to HA-associated high-surface-area, pure metal (hydr)oxides or clay minerals illustrating that loading levels of HA significantly impacted sorption affinity (i.e., K(oc)) and linearity (i.e., n) for particularly hydrophobic compounds (i.e., phenanthrene, anthracene and pyrene) due to the changes in fractionation, and structural and chemical properties of mineral-bound HA, the subsequent changes of sorption affinity and linearity appeared to be insignificant for the sorption of organic compounds with relatively high S(w) to low-surface-area metal (hydr)oxide- and HA-coated sands with low f(oc) values. Thus, the predictive models for the sorption of organic compounds with relatively high S(w) to low-surface-area metal (hydr)oxide- and HA-coated sands may not be remarkably improved by incorporating the complex changes of sorption affinity and linearity caused by the changes in fractionation, and structural and chemical properties of mineral-bound HA, although the mineral surfaces

  15. Inorganic-organic hybrid coatings on stainless steel by layer-by-layer deposition and surface-initiated atom-transfer-radical polymerization for combating biocorrosion.

    PubMed

    Yuan, S J; Pehkonen, S O; Ting, Y P; Neoh, K G; Kang, E T

    2009-03-01

    To improve the biocorrosion resistance of stainless steel (SS) and to confer the bactericidal function on its surface for inhibiting bacterial adhesion and biofilm formation, well-defined inorganic-organic hybrid coatings, consisting of the inner compact titanium oxide multilayers and outer dense poly(vinyl-N-hexylpyridinium) brushes, were successfully developed. Nanostructured titanium oxide multilayer coatings were first built up on the SS substrates via the layer-by-layer sol-gel deposition process. The trichlorosilane coupling agent, containing the alkyl halide atom-transfer-radical polymerization (ATRP) initiator, was subsequently immobilized on the titanium oxide coatings for surface-initiated ATRP of 4-vinylpyridine (4VP). The pyridium nitrogen moieties of the covalently immobilized 4VP polymer, or P(4VP), brushes were quaternized with hexyl bromide to produce a high concentration of quaternary ammonium salt on the SS surfaces. The excellent antibacterial efficiency of the grafted polycations, poly(vinyl-N-pyridinium bromide), was revealed by viable cell counts and atomic force microscopy images of the surface. The effectiveness of the hybrid coatings in corrosion protection was verified by the Tafel plot and electrochemical impedance spectroscopy measurements. PMID:20355986

  16. Chronic TiO₂ nanoparticle exposure to a benthic organism, Hyalella azteca: impact of solar UV radiation and material surface coatings on toxicity.

    PubMed

    Wallis, Lindsay K; Diamond, Stephen A; Ma, Hongbo; Hoff, Dale J; Al-Abed, Souhail R; Li, Shibin

    2014-11-15

    There is limited information on the chronic effects of nanomaterials to benthic organisms, as well as environmental mitigating factors that might influence this toxicity. The present study aimed to fill these data gaps by examining various growth endpoints (weight gain, instantaneous growth rate, and total protein content) for up to a 21 d sediment exposure of TiO2 nanoparticles (nano-TiO2) to a representative benthic species, Hyalella azteca. An uncoated standard, P25, and an Al(OH)3 coated nano-TiO2 used in commercial products were added to sediment at 20 mg/L or 100 mg/L Under test conditions, UV exposure alone was shown to be a greater cause of toxicity than even these high levels of nano-TiO2 exposure, indicating that different hazards need to be addressed in toxicity testing scenarios. In addition, this study showed the effectiveness of a surface coating on the decreased photoactivity of the material, as the addition of an Al(OH)3 coating showed a dramatic decrease in reactive oxygen species (ROS) production. However, this reduced photoactivity was found to be partially restored when the coating had been degraded, leading to the need for future toxicity tests which examine the implications of weathering events on particle surface coatings. PMID:25203828

  17. Polyester based hybrid organic coatings

    NASA Astrophysics Data System (ADS)

    Wang, Xiaojiang

    Polyesters are a class of polymers widely used in organic coatings applications. In this work, four types of organic coatings based on polyester polyols were prepared: UV-curable polyester/poly(meth)acrylate coatings, thermal curable polyester polyurethane-urea coatings, thermal curable non-isocyanate polyurethane coatings, and UV-curable non-isocyanate polyurethane coatings. Polyester/poly(meth)acrylate block copolymers are synthesized using a combination of polycondensation and Atom-Transfer Radical Polymerization (ATRP). All block copolymers are characterized by means of Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC). In the case of unsaturated-polyester-based block copolymers the main chain double bond in the polyester backbone remains almost unaffected during ATRP. The unsaturated block copolymers are crosslinkable and can form networks upon photo-irradiation in the presence of a suitable photoinitiator. These copolymers might be interesting candidates for coatings with better overall properties than those based on neat polyesters. Thermal curable polyester polyol based Polyurethane-Urea (PUU) coatings were formulated using Partially Blocked HDI isocyanurate (PBH), Isophorone Diamine (IPDA), and polyester polyol. As a comparison, the polyurethane coatings (PU) without adding IPDA were also prepared. The mechanical and viscoelastic properties of the PUU and PU coating were investigated by using tensile test and Dynamic Mechanical Thermal Analyzer (DMTA). It was found that PUU coating exhibited higher crosslink density, Tg, tensile modulus and strength than the corresponding PU coating. Thermal curable non-isocyanate polyurethane coatings were prepared by using polyamine and cyclic carbonate terminated polyester. Cyclic carbonate terminated polyester was synthesized from the reaction of the carbon dioxide and epoxidized polyester which was prepared from the polyester polyol. The properties of the epoxidized and cyclic carbonate

  18. 40 CFR Table 2 to Subpart II of... - Volatile Organic HAP (VOHAP) Limits for Marine Coatings

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (Surface Coating) Pt. 63, Subpt. II, Table 2 Table 2 to Subpart II of Part 63—Volatile Organic HAP (VOHAP) Limits for Marine Coatings Coating category VOHAP limits a b c Grams/liter coating (minus water and... VOHAP limits expressed in units of mass of VOHAP per volume of coating assuming the coatings contain...

  19. 40 CFR Table 2 to Subpart II of... - Volatile Organic HAP (VOHAP) Limits for Marine Coatings

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (Surface Coating) Pt. 63, Subpt. II, Table 2 Table 2 to Subpart II of Part 63—Volatile Organic HAP (VOHAP) Limits for Marine Coatings Coating category VOHAP limits a,b,c Grams/liter coating (minus water and... VOHAP limits expressed in units of mass of VOHAP per volume of coating assuming the coatings contain...

  20. 40 CFR 63.5752 - How do I calculate the organic HAP content of aluminum recreational boat surface coatings?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... clear coat i used in the past 12 months, liters. Di= density of coating i, kilograms per liter. Wi= mass... of thinner, activator, or additive k used in the past 12 months, liters. Dk= density of...

  1. 40 CFR 63.5752 - How do I calculate the organic HAP content of aluminum recreational boat surface coatings?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... clear coat i used in the past 12 months, liters. Di= density of coating i, kilograms per liter. Wi= mass... of thinner, activator, or additive k used in the past 12 months, liters. Dk= density of...

  2. Electrochemical formation of self-organized anodic nanotube coating on Ti-28Zr-8Nb biomedical alloy surface.

    PubMed

    Feng, X J; Macak, J M; Albu, S P; Schmuki, P

    2008-03-01

    In recent years, Ti-Zr-Nb alloys have become increasingly attractive as biomedical implant materials. In the present communication, we report the formation of self-organized nanotube oxide layers on a Ti-28Zr-8Nb biomedical alloy surface in 1M (NH4)2SO4 containing 0.25M NH4F. The morphology of the nanotube layers (the diameter and the length) is affected by the electrochemical conditions used (applied potential and time). Under specific conditions oxide layers consisting of highly ordered nanotubes with a wide range of diameters and lengths can be formed, varying, respectively, from approx. 50 to 300nm and from approx. 500nm to 22microm. The present results are highly promising for this biomedical alloy, as the large surface area and the tunable nanoscale geometry of the surface oxide provide novel pathways for the interaction of the materials with biorelevant species, such as cells and proteins. PMID:17923448

  3. Fungal alteration of organic coatings on sand grains

    NASA Astrophysics Data System (ADS)

    Rothhardt, S.; Gleixner, G.; Benzerara, K.; Fischer, C.; Gaupp, R.

    2012-04-01

    We studied the fungal alteration of organically coated sand particles, sampled in Eocene sediments in the open cast mining Profen, near Leipzig (Germany). These organic coatings were formed on sand grains after their sedimentation owing to mobilization of organic matter from younger coal layers. The organic coatings formed non-continuous layers on quartz grains, measuring few micrometers up to 30 µm in thickness. It has been shown that organic coatings on sand grains retain efficiently dissolved metals by adsorption from groundwaters. They consequently might be used as adsorbent to purify low heavy metal contaminated water. However, their stability has not been assessed yet especially in the oxic environment and, more specifically, in the presence of microorganisms. This is important in order to evaluate whether coated sands could act as a reliable tool in remediation. In order to address this question we characterized the fungal alteration of organic coatings on sand grains using several techniques, including scanning electron microscopy (SEM), scanning transmission X-ray microscopy (STXM) and vertical scanning interferometry (VSI). Sand grains coated with organics were incubated on complex yeast medium with and without Schizophyllum commune to estimate changes in heavy metal retention. Formation of biominerals and etch pits is induced by fungal colonization as shown by SEM. Surface topography analysis was performed using VSI technique. Etch pit depth ranges from 0.5 to 1 µm. Pit formation is limited to the organic coating; dissolution of quartz grains was not detected. Using STXM we measured near-edge X-ray absorption fine structure (NEXAFS) spectra at the C K-edge, N-edge, and O K-edge to characterize the different organic compartments (fungi, genuine organic coatings, altered organic coatings) down to the 25-nm scale. We observed in the spectra measured at the C K-edge on the altered organic coatings a decrease in aromatic and phenolic groups as well as an

  4. Combinatorial materials research applied to the development of new surface coatings X: a high-throughput electrochemical impedance spectroscopy method for screening organic coatings for corrosion inhibition.

    PubMed

    He, Jie; Bahr, James; Chisholm, Bret J; Li, Jun; Chen, Zhigang; Balbyshev, Séva N; Bonitz, Verena; Bierwagen, Gordon P

    2008-01-01

    The objective of the study was to develop a high-throughput electrochemical impedance spectroscopy (HT-EIS) method for rapid and quantitative evaluation of corrosion protective coatings. A 12-element, spatially addressable electrochemical platform was designed, fabricated, and validated. This platform was interfaced to a commercial EIS instrument through an automated electronic switching unit. The HT-EIS system enables four parallel EIS measurements to be run simultaneously, which significantly reduces characterization time compared to that of serial EIS measurements using a multiplexer. The performance of the HT-EIS system was validated using a series of model systems, including a Randles equivalent circuit, an electrochemical reaction (Ti/K4FeCN6, K3FeCN6), a highly uniform polymer film, and several polymer coatings. The results of the validation studies showed that the HT-EIS system enables a major reduction in characterization time and provides high quality data comparable to data obtained with conventional, single-cell EIS measurement systems. PMID:18582116

  5. Electromagnetic properties of material coated surfaces

    NASA Technical Reports Server (NTRS)

    Beard, L.; Berrie, J.; Burkholder, R.; Dominek, A.; Walton, E.; Wang, N.

    1989-01-01

    The electromagnetic properties of material coated conducting surfaces were investigated. The coating geometries consist of uniform layers over a planar surface, irregularly shaped formations near edges and randomly positioned, electrically small, irregularly shaped formations over a surface. Techniques to measure the scattered field and constitutive parameters from these geometries were studied. The significance of the scattered field from these geometries warrants further study.

  6. Abrasion-resistant coatings for plastic surfaces

    NASA Technical Reports Server (NTRS)

    Wydeven, T.; Hollahan, J. R.

    1976-01-01

    Optically clear composition of organosilicon compounds insulates plastic surfaces and protects them from abrasion. Plasma polymerization process produces superior uniformity and clarity than previous coating techniques.

  7. Assessment of Runoff Toxicity from Coated Surfaces

    EPA Science Inventory

    Presented in this paper are results from a field and laboratory study of the potential runoff toxicity from coated surfaces. The study results qualified and quantified the types and concentrations of pollutants in runoff from surfaces sealed with a variety of products. Coatings a...

  8. Organic/inorganic hybrid coatings for anticorrosion

    NASA Astrophysics Data System (ADS)

    He, Zhouying

    Compared to organic coatings, organic-inorganic hybrid coatings can potentially improve the anticorrosion performance. The organic phase provides the excellent mechaincal and barrier properties while the inorganic phase acts as an adhesion promoter and corrosion inhibitor. Despite that many studies on alkoxylsilane-based hybrid coatings have been developed and studied, their weatherability and anticorrosion performance has been rarely evaluated. On the other hand, organic-inorganic hybrid coatings based on mixed sol-gel precursors have received much less attention compared to alkoxylsilane-based hybrid coatings. In the first part, polyurethane hybrid coatings with a unique hybrid crosslinked structure as an improved unicoat were successfully prepared. The effect of polyesters on physical properties of the hybrid coatings was studied. Polyurethane coatings derived from cycloaliphatic polyester show comparable properties than those derived from the commercially viable aromatic polyester. Introducing the polysiloxane part into the polyurethane coatings enhanced the crosslinking density, Tg, mechanical properties, and general coating properties. The increased adhesion between the hybrid coating and the substrate make the hybrid coating a good candidate for anticorrosion application, which is shown by electrochemical impedance spectroscopy (EIS). The degradation mechanism of the polyurethane/polysiloxane hybrid coatings under various weathering conditions was shown to be the scission of the urethane and ester groups in the organic phase along with reorganizing and rearranging of the inorganic phase. The anticorrosion performance of the cycloaliphatic hybrid was much better than that of aromatic based hybrid under outdoor weathering based on visual observation and EIS analysis. Acid undercutting is an issue for TEOS based hybrid coating. In the second part, design of experiments (DOEs) was used to statistically investigate on the effect of sol-gel precursors. The

  9. Surface functionalization with strontium-containing nanocomposite coatings via EPD.

    PubMed

    Ma, Kena; Huang, Dan; Cai, Jing; Cai, Xinjie; Gong, Lingling; Huang, Pin; Wang, Yining; Jiang, Tao

    2016-10-01

    Metal orthopedic implants still face challenges in some compromised conditions, partly due to bio-inertness. The present study aimed to functionalize metallic implants with organic-inorganic nanocomposite (strontium-containing chitosan/gelatin) coatings through a simple single-step electrophoretic deposition under mild conditions. The surface characterization and in vitro cellular response were studied and compared with chitosan/gelatin (CS/G) coatings. SEM images suggested the inorganic nanoparticles may be encapsulated within or mixed with organic polymers. The XRD patterns showed that strontium carbonate was generated in the coatings. The TEM images revealed strontium-containing nanoparticles were released from the coatings in PBS. The continuous release after the initial burst release ensured the enduring effects of the functionalized surface. The tensile bond strength of the coatings to the substrates increased after the addition of strontium. In vitro cellular study confirmed that strontium-containing coatings supported the proliferation of MC3T3-E1 cells and exhibited excellent ability to enhance the differentiation of such pre-osteoblasts. Therefore, such organic-inorganic nanocomposite coatings are a promising candidate to functionalize orthopedic implant surfaces. PMID:27262259

  10. Surface roughness of anodized titanium coatings.

    SciTech Connect

    Dugger, Michael Thomas; Chinn, Douglas Alan

    2010-10-01

    Samples of grade five 6Al4V titanium alloy were coated with two commercial fluoropolymer anodizations (Tiodize and Canadize) and compared. Neither coating demonstrates significant outgassing. The coatings show very similar elemental analysis, except for the presence of lead in the Canadize coating, which may account for its lower surface friction in humid environments. Surface roughness has been compared by SEM, contact profilometry, optical profilometry, power spectral density and bidirectional scattering distribution function (BSDF). The Tiodize film is slightly smoother by all measurement methods, but the Canadize film shows slightly less scatter at all angles of incidence. Both films exhibited initial friction coefficients of 0.2 to 0.4, increasing to 0.4 to 0.8 after 1000 cycles of sliding due to wear of the coating and ball. The coatings are very similar and should behave identically in most applications.

  11. GUIDE TO CLEANER TECHNOLOGIES: ORGANIC COATING REPLACEMENTS

    EPA Science Inventory

    This guide describes available and emerging cleaner technologies that can be used to reduce emissions and wastes from paint and coatings applications. Environmental concerns and increasing costs of organic chemicals and metals are leading to changes in the formulation of organic ...

  12. METHOD OF COATING SURFACES WITH BORON

    DOEpatents

    Martin, G.R.

    1949-10-11

    A method of forming a thin coating of boron on metallic, glass, or other surfaces is described. The method comprises heating the article to be coated to a temperature of about 550 d C in an evacuated chamber and passing trimethyl boron, triethyl boron, or tripropyl boron in the vapor phase and under reduced pressure into contact with the heated surface causing boron to be deposited in a thin film.

  13. Anticorrosive organic/inorganic hybrid coatings

    NASA Astrophysics Data System (ADS)

    Gao, Tongzhai

    Organic/inorganic hybrid coating system was developed for anticorrosion applications using polyurea, polyurethane or epoxide as the organic phase and polysiloxane, formed by sol-gel process, as the inorganic phase. Polyurea/polysiloxane hybrid coatings were formulated and moisture cured using HDI isocyanurate, alkoxysilane-functionalized HDI isocyanurate, and tetraethyl orthosilicate (TEOS) oligomers. Two urethanes were prepared using the same components as abovementioned in addition to the oligoesters derived from either cyclohexane diacids (CHDA) and 2-butyl-2-ethyl-1,3-propanediol (BEPD) or adipic acid (AA), isophthalic acid (IPA), 1,6-hexanediol (HD), and trimethylol propane (TMP). Accelerated weathering and outdoor exposure were performed to study the weatherability of the polyurethane/polysiloxane hybrid coating system. FTIR and solid-state 13C NMR revealed that the degradation of the hybrid coatings occurred at the urethane and ester functionalities of the organic phase. DMA and DSC analyses showed the glass transition temperature increased and broadened after weathering. SEM was employed to observe the change of morphology of the hybrid coatings and correlated with the gloss variation after weathering. Rutile TiO2 was formulated into polyurethane/polysiloxane hybrid coatings in order to investigate the effect of pigmentation on the coating properties and the sol-gel precursor. Chemical interaction between the TiO2 and the sol-gel precursor was investigated using solid-state 29Si NMR and XPS. The morphology, mechanical, viscoelastic, thermal properties of the pigmented coatings were evaluated as a function of pigmentation volume concentration (PVC). Using AFM and SEM, the pigment were observed to be well dispersed in the polymer matrix. The thermal stability, the tensile modulus and strength of the coatings were enhanced with increasing PVC, whereas the pull-off adhesion and flexibility were reduced with increasing PVC. Finally, the pigmented coatings were

  14. Optical mirror coated with organic superconducting material

    NASA Astrophysics Data System (ADS)

    Lake, John A.; Heath, William B.

    1988-08-01

    An optical mirror has enhanced reflectivity and reduced thermal distortions when it is composed of a substrate coated with a reflective coating made of an organic superconducting material. The substrate is best constructed of materials which have the most favorable thermal expansion and thermal conduction characteristics at temperatures near 0 K. such as: silicon, diamond, copper, and sapphire. The reflective coating is only a few microns thick and composed of organometallic compounds and is cooled to superconducting or cryogenic temperatures of less than 100 K.

  15. Fluoropolymer surface coatings to control droplets in microfluidic devices.

    PubMed

    Riche, Carson T; Zhang, Chuchu; Gupta, Malancha; Malmstadt, Noah

    2014-06-01

    We have demonstrated the application of low surface energy fluoropolymer coatings onto poly(dimethylsiloxane) (PDMS) microfluidic devices for droplet formation and extraction-induced merger of droplets. Initiated chemical vapor deposition (iCVD) was used to pattern fluoropolymer coatings within microchannels based on geometrical constraints. In a two-phase flow system, the range of accessible flow rates for droplet formation was greatly enhanced in the coated devices. The ability to controllably apply the coating only at the inlet facilitated a method for merging droplets. An organic spacer droplet was extracted from between a pair of aqueous droplets. The size of the organic droplet and the flow rate controlled the time to merge the aqueous droplets; the process of merging was independent of the droplet sizes. Extraction-induced droplet merging is a robust method for manipulating droplets that could be applied in translating multi-step reactions to microfluidic platforms. PMID:24722827

  16. Mussel-inspired surface chemistry for multifunctional coatings.

    PubMed

    Lee, Haeshin; Dellatore, Shara M; Miller, William M; Messersmith, Phillip B

    2007-10-19

    We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin, surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules. PMID:17947576

  17. Surface dynamics and mechanics in liquid crystal polymer coatings

    NASA Astrophysics Data System (ADS)

    Liu, Danqing; Broer, Dirk J.

    2015-03-01

    Based on liquid crystal networks we developed `smart' coatings with responsive surface topographies. Either by prepatterning or by the formation of self-organized structures they can be switched on and off in a pre-designed manner. Here we provide an overview of our methods to generate coatings that form surface structures upon the actuation by light. The coating oscillates between a flat surface and a surface with pre-designed 3D micro-patterns by modulating a light source. With recent developments in solid state lighting, light is an attractive trigger medium as it can be integrated in a device for local control or can be used remotely for flood or localized exposure. The basic principle of formation of surface topographies is based on the change of molecular organization in ordered liquid crystal polymer networks. The change in order leads to anisotropic dimensional changes with contraction along the director and expansion to the two perpendicular directions and an increase in volume by the formation of free volume. These two effects work in concert to provide local expansion and contraction in the coating steered by the local direction of molecular orientation. The surface deformation, expressed as the height difference between the activated regions and the non-activated regions divided by the initial film thickness, is of the order of 20%. Switching occurs immediately when the light is switched `on' and `off' and takes several tens of seconds.

  18. Sol-gel approach to in situ creation of high pH-resistant surface-bonded organic-inorganic hybrid zirconia coating for capillary microextraction (in-tube SPME).

    PubMed

    Alhooshani, Khalid; Kim, Tae-Young; Kabir, Abuzar; Malik, Abdul

    2005-01-01

    A novel zirconia-based hybrid organic-inorganic sol-gel coating was developed for capillary microextraction (CME) (in-tube SPME). High degree of chemical inertness inherent in zirconia makes it very difficult to covalently bind a suitable organic ligand to its surface. In the present work, this problem was addressed from a sol-gel chemistry point of view. Principles of sol-gel chemistry were employed to chemically bind a hydroxy-terminated silicone polymer (polydimethyldiphenylsiloxane, PDMDPS) to a sol-gel zirconia network in the course of its evolution from a highly reactive alkoxide precursor undergoing controlled hydrolytic polycondensation reactions. A fused silica capillary was filled with a properly designed sol solution to allow for the sol-gel reactions to take place within the capillary for a predetermined period of time (typically 15-30 min). In the course of this process, a layer of the evolving hybrid organic-inorganic sol-gel polymer got chemically anchored to the silanol groups on the capillary inner walls via condensation reaction. At the end of this in-capillary residence time, the unbonded part of the sol solution was expelled from the capillary under helium pressure, leaving behind a chemically bonded sol-gel zirconia-PDMDPS coating on the inner walls. Polycyclic aromatic hydrocarbons, ketones, and aldehydes were efficiently extracted and preconcentrated from dilute aqueous samples using sol-gel zirconia-PDMDPS coated capillaries followed by thermal desorption and GC analysis of the extracted solutes. The newly developed sol-gel hybrid zirconia coatings demonstrated excellent pH stability, and retained the extraction characteristics intact even after continuous rinsing with a 0.1 M NaOH solution for 24 h. To our knowledge, this is the first report on the use of a sol-gel zirconia-based hybrid organic-inorganic coating as an extraction medium in solid phase microextraction (SPME). PMID:15679137

  19. Surface coatings and catalyst production by electrodeposition

    NASA Technical Reports Server (NTRS)

    May, Chester B.; Riley, Clyde; Coble, H. Dwain; Loo, Boon H.

    1987-01-01

    Electrodeposition and electrocodeposition in low gravity are discussed. The goal is to provide a better understanding of the role of convection and buoyancy in the mechanisms of formation of some electrodeposited surfaces, fluid flow in the vicinity of electrodepositing surfaces, the influence of a moving medium upon codeposition, the effect of gravity upon the dispersion (coagulation) of neutral particles that are desired for codeposition and preparation of improved surface coatings and metal catalysts.

  20. Coatings and Surface Treatments for Reusable Entry Systems

    NASA Technical Reports Server (NTRS)

    Johnson, Sylvia M.

    2016-01-01

    This talk outlines work in coatings for TPS done at NASA Ames. coatings and surface treatments on reusable TPS are critical for controlling the behavior of the materials. coatings discussed include RCG, TUFI and HETC. TUFROc is also discussed.

  1. Surface coating for prevention of crust formation

    DOEpatents

    Kronberg, James W.

    1994-01-01

    A flexible surface coating which promotes the removal of deposits as they reach the surface by preventing adhesion and crust formation. Flexible layers are attached to each side of a flexible mesh substrate comprising of a plurality of zones composed of one or more neighboring cells, each zone having a different compressibility than its adjacent zones. The substrate is composed of a mesh made of strands and open cells. The cells may be filled with foam. Studs or bearings may also be positioned in the cells to increase the variation in compressibility and thus the degree of flexing of the coating. Surface loading produces varying amounts of compression from point to point causing the coating to flex as deposits reach it, breaking up any hardening deposits before a continuous crust forms. Preferably one or more additional layers are also used, such as an outer layer of a non-stick material such as TEFLON, which may be pigmented, and an inner, adhesive layer to facilitate applying the coating to a surface.

  2. Facile cell patterning on an albumin-coated surface.

    PubMed

    Yamazoe, Hironori; Uemura, Toshimasa; Tanabe, Toshizumi

    2008-08-19

    Fabrication of micropatterned surfaces to organize and control cell adhesion and proliferation is an indispensable technique for cell-based technologies. Although several successful strategies for creating cellular micropatterns on substrates have been demonstrated, a complex multistep process and requirements for special and expensive equipment or materials limit their prevalence as a general experimental tool. To circumvent these problems, we describe here a novel facile fabrication method for a micropatterned surface for cell patterning by utilizing the UV-induced conversion of the cell adhesive property of albumin, which is the most abundant protein in blood plasma. An albumin-coated surface was prepared by cross-linking albumin with ethylene glycol diglycidyl ether and subsequent casting of the cross-linked albumin solution on the cell culture dish. While cells did not attach to the albumin surface prepared in this way, UV exposure renders the surface cell-adhesive. Thus, surface micropatterning was achieved simply by exposing the albumin-coated surface to UV light through a mask with the desired pattern. Mouse fibroblast L929 cells were inoculated on the patterned albumin substrates, and cells attached and spread in a highly selective manner according to the UV-irradiated pattern. Although detailed investigation of the molecular-level mechanism concerning the change in cell adhesiveness of the albumin-coated surface is required, the present results would give a novel facile method for the fabrication of cell micropatterned surfaces. PMID:18627191

  3. Surface property modification of coatings via self-stratification

    NASA Astrophysics Data System (ADS)

    Pieper, Robert Joseph

    Biological fouling occurs everywhere in the marine environment and is a significant problem for marine vessels. Anti-fouling coatings have been used effectively to prevent fouling; however, these coatings harm non-targeted sea-life. Fouling-release coatings (FRC) appear to be an alternative way to combat fouling. FRC do not necessarily prevent the settlement of marine organisms but rather allow their easy removal with application of shear to the coatings surface. These coatings must be non-toxic, non-leaching, have low surface energy, low modulus, and durability to provide easy removal of marine organisms. Here the goal is to develop FRC based on thermosetting siloxane-polyurethane, amphiphilic polyurethane, and zwitterionic/amphiphilic polyurethane systems. A combinatorial high-throughput approach has been taken in order to explore the variables that may affect the performance of the final coatings. Libraries of acrylic polyols were synthesized using combinatorial high-throughput techniques by either batch or semi-batch processes. The design of the experiments for the batch and semi-batch processes were done combinatorially to explore a range of compositions and various reaction process variables that cannot be accomplished or are not suitable for single reaction experiments. Characterization of Rapid-GPC, high-throughput DSC, and gravimetrically calculated percent solids verified the effects of different reaction conditions on the MW, glass transition temperatures, and percent conversion of the different compositions of acrylic polyols. Coatings were characterized for their surface energy, pseudobarnacle pull-off adhesion, and were subjected to bioassays including marine bacteria, algae, and barnacles. From the performance properties results the acrylic polyol containing 20% hydroxyethyl acrylate and 80% butyl acrylate was selected for further siloxane-polyurethane formulations and were subjected to the same physical, mechanical, and performance testing

  4. Organic matrix composite protective coatings for space applications

    NASA Technical Reports Server (NTRS)

    Dursch, Harry W.; George, Pete

    1995-01-01

    Successful use of composites in low earth orbit (LEO) depends on their ability to survive long-term exposure to atomic oxygen (AO), ultraviolet radiation, charged particle radiation, thermal cycling, and micrometeoroid and space debris. The AO environment is especially severe for unprotected organic matrix composites surfaces in LEO. Ram facing unprotected graphite/epoxy flown on the 69-month Long Duration Exposure Facility (LDEF) mission lost up to one ply of thickness (5 mils) resulting in decreased mechanical properties. The expected AO fluence of the 30 year Space Station Alpha mission is approximately 20 times that seen on LDEF. This exposure would result in significant material loss of unprotected ram facing organic matrix composites. Several protective coatings for composites were flown on LDEF including anodized aluminum, vacuum deposited coatings, a variety of thermal control coatings, metalized Teflon, and leafing aluminum. Results from the testing and analysis of the coated and uncoated composite specimens flown on LDEF's leading and trailing edges provide the baseline for determining the effectiveness of protectively coated composites in LEO. In addition to LDEF results, results from shuttle flight experiments and ground based testing will be discussed.

  5. Organic matrix composite protective coatings for space applications

    SciTech Connect

    Dursch, H.W.; George, P.

    1995-02-01

    Successful use of composites in low earth orbit (LEO) depends on their ability to survive long-term exposure to atomic oxygen (AO), ultraviolet radiation, charged particle radiation, thermal cycling, and micrometeoroid and space debris. The AO environment is especially severe for unprotected organic matrix composites surfaces in LEO. Ram facing unprotected graphite/epoxy flown on the 69-month Long Duration Exposure Facility (LDEF) mission lost up to one ply of thickness (5 mils) resulting in decreased mechanical properties. The expected AO fluence of the 30 year Space Station Alpha mission is approximately 20 times that seen on LDEF. This exposure would result in significant material loss of unprotected ram facing organic matrix composites. Several protective coatings for composites were flown on LDEF including anodized aluminum, vacuum deposited coatings, a variety of thermal control coatings, metalized Teflon, and leafing aluminum. Results from the testing and analysis of the coated and uncoated composite specimens flown on LDEF`s leading and trailing edges provide the baseline for determining the effectiveness of protectively coated composites in LEO. In addition to LDEF results, results from shuttle flight experiments and ground based testing will be discussed.

  6. Method for smoothing the surface of a protective coating

    DOEpatents

    Sangeeta, D.; Johnson, Curtis Alan; Nelson, Warren Arthur

    2001-01-01

    A method for smoothing the surface of a ceramic-based protective coating which exhibits roughness is disclosed. The method includes the steps of applying a ceramic-based slurry or gel coating to the protective coating surface; heating the slurry/gel coating to remove volatile material; and then further heating the slurry/gel coating to cure the coating and bond it to the underlying protective coating. The slurry/gel coating is often based on yttria-stabilized zirconia, and precursors of an oxide matrix. Related articles of manufacture are also described.

  7. High temperature low friction surface coating

    DOEpatents

    Bhushan, Bharat

    1980-01-01

    A high temperature, low friction, flexible coating for metal surfaces which are subject to rubbing contact includes a mixture of three parts graphite and one part cadmium oxide, ball milled in water for four hours, then mixed with thirty percent by weight of sodium silicate in water solution and a few drops of wetting agent. The mixture is sprayed 12-15 microns thick onto an electro-etched metal surface and air dried for thirty minutes, then baked for two hours at 65.degree. C. to remove the water and wetting agent, and baked for an additional eight hours at about 150.degree. C. to produce the optimum bond with the metal surface. The coating is afterwards burnished to a thickness of about 7-10 microns.

  8. Surface pressure field mapping using luminescent coatings

    NASA Technical Reports Server (NTRS)

    Mclachlan, B. G.; Kavandi, J. L.; Callis, J. B.; Gouterman, M.; Green, E.; Khalil, G.; Burns, D.

    1993-01-01

    In recent experiments we demonstrated the feasibility of using the oxygen dependence of luminescent molecules for surface pressure measurement in aerodynamic testing. This technique is based on the observation that for many luminescent molecules the light emitted increases as the oxygen partial pressure, and thus the air pressure, the molecules see decreases. In practice the surface to be observed is coated with an oxygen permeable polymer containing a luminescent molecule and illuminated with ultraviolet radiation. The airflow induced surface pressure field is seen as a luminescence intensity distribution which can be measured using quantitative video techniques. Computer processing converts the video data into a map of the surface pressure field. The experiments consisted of evaluating a trial luminescent coating in measuring the static surface pressure field over a two-dimensional NACA-0012 section model airfoil for Mach numbers ranging from 0.3 and 0.66. Comparison of the luminescent coating derived pressures were made to those obtained from conventional pressure taps. The method along with the experiment and its results will be described.

  9. The passivation of pyrrhotite by surface coating.

    PubMed

    Cai, Mei-Fang; Dang, Zhi; Chen, Yu-Wei; Belzile, Nelson

    2005-11-01

    The potential of triethylenetetramine (TETA) to inhibit the oxidation of three pyrrhotites, Garson, McCreedy and Po-97 has been studied systematically and confirmed by comparing the release of Fe and SO4(2-) from samples with and without coating treatment. Each sample, original or coated by TETA, was exposed to oxygen, 1 x 10(-3) M FeCl3, and Acidithiobacillus ferrooxidans, respectively, for specific oxidation periods. Both abiotic and biotic oxidation of samples treated by this passivating agent has been reduced significantly in this study. Under the aerobic condition, lower concentrations of ferric, total Fe or SO4(2-) were obtained from the coated samples than those from the uncoated samples. In the presence of 1 x 10(-3) M FeCl3 at 30 degrees C, TETA was able to reduce oxidation rates of Garson, McCreedy and Po-97 by 83%, 79%, and 81% (based on Fe release), respectively. A higher pH, lower Eh, and lower concentrations of total Fe and SO4(2-) were also observed in the biotic oxidation of coated Garson by Acidithiobacillus ferrooxidans. The protection of pyrrhotite surface from oxidant attack by TETA barrier and the alkaline property of this coating agent can be used to interpret the inhibition of oxidation. PMID:16219502

  10. Surface figure control for coated optics

    DOEpatents

    Ray-Chaudhuri, Avijit K.; Spence, Paul A.; Kanouff, Michael P.

    2001-01-01

    A pedestal optical substrate that simultaneously provides high substrate dynamic stiffness, provides low surface figure sensitivity to mechanical mounting hardware inputs, and constrains surface figure changes caused by optical coatings to be primarily spherical in nature. The pedestal optical substrate includes a disk-like optic or substrate section having a top surface that is coated, a disk-like base section that provides location at which the substrate can be mounted, and a connecting cylindrical section between the base and optics or substrate sections. The optic section has an optical section thickness.sup.2 /optical section diameter ratio of between about 5 to 10 mm, and a thickness variation between front and back surfaces of less than about 10%. The connecting cylindrical section may be attached via three spaced legs or members. However, the pedestal optical substrate can be manufactured from a solid piece of material to form a monolith, thus avoiding joints between the sections, or the disk-like base can be formed separately and connected to the connecting section. By way of example, the pedestal optical substrate may be utilized in the fabrication of optics for an extreme ultraviolet (EUV) lithography imaging system, or in any optical system requiring coated optics and substrates with reduced sensitivity to mechanical mounts.

  11. Hydroxyapatite Coatings Produced by Surface-Induced Mineralizaiton

    SciTech Connect

    Campbell, Allison A.; Deatherage, Brooke L.; Li, Xiaohong S.; Nelson, Bradley J.; Bottoni, Craig R.; Dejong, E. Schuyler

    2002-01-03

    The surface-induced mineralization (SIM) process is based on the observation that, in nature, organisms use biopolymers to produce ceramic composites such as teeth, bones, and shells. The SIM process involves modification of a surface to introduce surface functionalization followed by immersion in aqueous supersaturated calcium phosphate solutions. This room temperature process has advantages over conventional methods of calcium phosphate deposition in that uniform coatings are produced onto complex-shaped and/or microporous samples. Additionally, because it is a room temperature process, biological agents can be incorporated.

  12. Molecular dynamics studies of organic-coated nano aerosols

    NASA Astrophysics Data System (ADS)

    Chakraborty, Purnendu

    2008-10-01

    Atmospheric aerosols play an important role in atmospheric processes. These aerosol particles can affect climate through scattering, transmission and absorption of radiation as well as acting as cloud condensation nuclei. It has recently been found that fatty acids reside on the surfaces of marine and continental aerosols. In this research, an attempt has been made to understand the structures and properties of such organic coated aerosols using Molecular Dynamics simulation. The model particle consisted of a water droplet coated with fatty acid. The density profile (using both Coarse-Grained and Atomistic/United atom models) demonstrated that such aerosol particles have an inverted micelle structure consisting of an aqueous core and with the hydrophobic hydrocarbon tails exposed to the atmosphere. For smaller chains, with the organic molecules directed radially outwards from the water---organic interface) the normal pressure profile showed that the organic coating is under tension resulting in a 'negative' surface tension. As a result, such particles would have an inverse Kelvin vapor pressure effect and would be able to process water vapor despite the hydrophobic surface. Following the work on surface tension, the rate of water uptake by coated aerosols was computed. It was found that the sticking coefficient of water vapor on such particles was about a sixth of that on pure water droplets. This may seem to imply that the net condensation rate is lower, but we also need to take into account the evaporation of water from such particles. With a significant reduction in the evaporation rate (the coating lends greater stability to the particle resulting in reduced evaporation rate), the equilibrium vapor pressure of water on such particles reduced, resulting in a "net water attractor". Thus if such structures were created in sufficient concentration, they might be important contributors in the cloud condensation process. Next the effect of longer Fatty acid molecules

  13. Conformal coating of highly structured surfaces

    SciTech Connect

    Ginley, David S.; Perkins, John; Berry, Joseph; Gennett, Thomas

    2012-12-11

    Method of applying a conformal coating to a highly structured substrate and devices made by the disclosed methods are disclosed. An example method includes the deposition of a substantially contiguous layer of a material upon a highly structured surface within a deposition process chamber. The highly structured surface may be associated with a substrate or another layer deposited on a substrate. The method includes depositing a material having an amorphous structure on the highly structured surface at a deposition pressure of equal to or less than about 3 mTorr. The method may also include removing a portion of the amorphous material deposited on selected surfaces and depositing additional amorphous material on the highly structured surface.

  14. Surface control and cryogenic durability of transparent CNT coatings on dip-coated glass substrates.

    PubMed

    Wang, Zuo-Jia; Kwon, Dong-Jun; Gu, Ga-Young; Devries, K Lawrence; Park, Joung-Man

    2012-11-15

    Transparent carbon nanotube (CNT) coatings were deposited on boro-silicate glass substrates by dip-coating. Ultraviolet-visible (UV) spectra, surface resistance measurement, and the wettability tests were used to investigate the optical transmittance and electrical properties of these CNT coatings. The changes in electrical and optical properties of these coatings were observed to be functions of the number of dip-coating cycles. The surface resistance of the CNT coated substrates decreased dramatically as the number of dip-coatings was increased, whereas the increases in the CNT layer thickness beyond that for the first dipping cycle had little effect on the transparent-properties. Static contact angle measurements proved to be an effective means for evaluating the surface morphology of CNT coatings. The interfacial durability of the CNT coatings on a glass substrate was much better than that of ITO coatings over the temperature range from -150°C to +150°C. PMID:22918050

  15. Free-surface and coating flows

    NASA Astrophysics Data System (ADS)

    Ashmore, Jacqueline

    In thus thesis we present results on four problems which fall into the class of free-surface flows. Two of the problems relate to coating flows, in which a thin film of fluid is deposited on a moving substrate. The third problem concerns the motion of a sphere down an inclined plane that is coated with a thin film of viscous fluid. Finally, we study the Rayleigh capillary instability of a cylindrical fluid thread surrounded by a second viscous fluid in a rotating frame. One useful tool for analysis of coating flows is the method of matched asymptotics, which enables us to obtain a solution to the nonlinear third-order differential equation that describes the free-surface shape in two of the problems we study. The first coating flow problem we consider is the interface shape of fluid inside a horizontal cylinder rotating about its axis with a small fraction of its volume filled with viscous Newtonian fluid. By accounting for surface tension effects we find a new axially uniform steady solution valid at low rotation rates. Predictions for the scalings based on matched asymptotic methods are confirmed numerically. Secondly, theoretical predictions of the film thickness that coats a substrate when it is withdrawn from a bath of viscoelastic fluid are presented, for a number of substrate geometries. In the third problem studied, we use lubrication analysis to characterize the steady translational velocity and rotation rate of a sphere that moves down an inclined plane, which is coated with a thin film of fluid, under the action of gravity. In this case, an understanding of the fluid flow must be used to determine the forces that act on the sphere, which set the translational speed and rotation rate of the sphere. Finally, we study the effect of the Coriolis force on the Rayleigh capillary instability of a cylindrical column of viscous liquid surrounded by a second viscous liquid in a rotating frame. Our study comprises numerical results of a temporal linear stability

  16. Handbook of Tribology: Materials, coatings, and surface treatments

    SciTech Connect

    Bhushan, B.; Gupta, B.K.

    1991-12-31

    This book provides an introduction to tribological principles as well as all types of coatings, surface treatments and modifications. The first chapter provides an overview of the various types of lubricants. Chapter two provides a review of friction, wear, and lubrication. Chapter three covers physics of tribological materials including the nature, shape, and properties of surfaces; surface interactions with the environment; phase equilibria; and microstructural effects on friction and wear. Chapter four covers metals and ceramics and chapter five covers solid lubricants and self-lubricating solids. Chapter six provides an overview of coating deposition and surface treatment techniques, including hard facing, vapor deposition, a variety of miscellaneous coating techniques, and surface treatment techniques including microstructural modification, diffusion treatments, and implantation techniques. This chapter also provides a section giving criteria for selecting coating material, deposition and surface treatment techniques. Chapter seven deals with surface preparation for coating deposition. Cleaning methods using solvents, emulsions, alkalines, acids, pickling, salt bath descaling, ultrasonics, and plasmas are described. Surface roughening techniques that are described include abrasive blasting, barrel finishing, mechanical polishing and buffing, chemical etching, and electro-polishing. The chapter concludes with a discussion of techniques for monitoring surface cleanliness and texture. Chapters 8-15 are devoted to much more detailed discussion of the following topics: coating deposition by hard facing; coating deposition from vapor phase; coating deposition by miscellaneous techniques; surface treatments by thermal and chemical processes; surface treatments by ion beams; soft coatings; hard coatings; and screening methodology for materials coatings and surface treatments.

  17. Organic electrode coatings for next-generation neural interfaces

    PubMed Central

    Aregueta-Robles, Ulises A.; Woolley, Andrew J.; Poole-Warren, Laura A.; Lovell, Nigel H.; Green, Rylie A.

    2014-01-01

    Traditional neuronal interfaces utilize metallic electrodes which in recent years have reached a plateau in terms of the ability to provide safe stimulation at high resolution or rather with high densities of microelectrodes with improved spatial selectivity. To achieve higher resolution it has become clear that reducing the size of electrodes is required to enable higher electrode counts from the implant device. The limitations of interfacing electrodes including low charge injection limits, mechanical mismatch and foreign body response can be addressed through the use of organic electrode coatings which typically provide a softer, more roughened surface to enable both improved charge transfer and lower mechanical mismatch with neural tissue. Coating electrodes with conductive polymers or carbon nanotubes offers a substantial increase in charge transfer area compared to conventional platinum electrodes. These organic conductors provide safe electrical stimulation of tissue while avoiding undesirable chemical reactions and cell damage. However, the mechanical properties of conductive polymers are not ideal, as they are quite brittle. Hydrogel polymers present a versatile coating option for electrodes as they can be chemically modified to provide a soft and conductive scaffold. However, the in vivo chronic inflammatory response of these conductive hydrogels remains unknown. A more recent approach proposes tissue engineering the electrode interface through the use of encapsulated neurons within hydrogel coatings. This approach may provide a method for activating tissue at the cellular scale, however, several technological challenges must be addressed to demonstrate feasibility of this innovative idea. The review focuses on the various organic coatings which have been investigated to improve neural interface electrodes. PMID:24904405

  18. Organic electrode coatings for next-generation neural interfaces.

    PubMed

    Aregueta-Robles, Ulises A; Woolley, Andrew J; Poole-Warren, Laura A; Lovell, Nigel H; Green, Rylie A

    2014-01-01

    Traditional neuronal interfaces utilize metallic electrodes which in recent years have reached a plateau in terms of the ability to provide safe stimulation at high resolution or rather with high densities of microelectrodes with improved spatial selectivity. To achieve higher resolution it has become clear that reducing the size of electrodes is required to enable higher electrode counts from the implant device. The limitations of interfacing electrodes including low charge injection limits, mechanical mismatch and foreign body response can be addressed through the use of organic electrode coatings which typically provide a softer, more roughened surface to enable both improved charge transfer and lower mechanical mismatch with neural tissue. Coating electrodes with conductive polymers or carbon nanotubes offers a substantial increase in charge transfer area compared to conventional platinum electrodes. These organic conductors provide safe electrical stimulation of tissue while avoiding undesirable chemical reactions and cell damage. However, the mechanical properties of conductive polymers are not ideal, as they are quite brittle. Hydrogel polymers present a versatile coating option for electrodes as they can be chemically modified to provide a soft and conductive scaffold. However, the in vivo chronic inflammatory response of these conductive hydrogels remains unknown. A more recent approach proposes tissue engineering the electrode interface through the use of encapsulated neurons within hydrogel coatings. This approach may provide a method for activating tissue at the cellular scale, however, several technological challenges must be addressed to demonstrate feasibility of this innovative idea. The review focuses on the various organic coatings which have been investigated to improve neural interface electrodes. PMID:24904405

  19. Surface analysis of lithium coatings in NSTX

    NASA Astrophysics Data System (ADS)

    Timberlake, J.; Kugel, H. W.; Skinner, C. H.; Yao, N.

    2007-11-01

    Lithium coatings have been applied to NSTX plasma facing surfaces as part of a long term program to explore the potential for lithium to improve plasma and PFC performance. A LIThium EvaporatoR (LITER) directed a collimated stream of lithium vapor from an upper vacuum vessel port toward the graphite tiles of the lower center stack and divertor either before, or continuously between and during, discharges. Silicon witness coupons and other samples were retrieved from the vacuum vessel after the campaign and the surface morphology and elemental compostion examined with a XL30 FEG-SEM microscope equipped with an energy dispersed X-rays system sensitive to elements with atomic number greater than 4. The surfaces showed a complex morphology with nucleation sites apparent. Carbon and oxygen were the dominant impurities. Trace metals (Fe and Cr) were detected in the coating on the Si coupon, but not in a flake of bulk Li. We will present results of the surface analysis of samples exposed to Li evaporation in NSTX.

  20. Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

    The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

  1. The surface coat of chylomicrons: lipid chemistry.

    PubMed

    Zilversmit, D B

    1968-03-01

    Chylomicrons from the thoracic duct lymph of dogs fed corn oil were isolated by centrifugation and disrupted by either freezing and thawing or rotary evaporation and rehydration. A pellet, representing the surface coat, was isolated by centrifugation. Pellets isolated by freezing and thawing contained a higher percentage of saturated triglycerides than pellets isolated by rotary evaporation; the presence of saturated triglyceride in the pellet was probably an artifact of the preparation of the surface coat material at low temperature. Exchange of free cholesterol between surface and core lipid of chylomicrons was complete within 1 hr. The percentage of cholesterol in pellets of surface material isolated by freezing and thawing was about twice that found for pellets after rotary evaporation at 25-40 degrees C. Cholesteryl ester was not present in the surface lipid and that present in the core lipid did not exchange with serum lipoprotein cholesteryl ester. For phosphatidyl choline, the percentage of linoleic acid in lymph chylomicrons was markedly higher than that in clear lymph or plasma, while the percentage of arachidonic acid was lower. Sphingomyelin of lymph chylomicrons was characterized by very high levels of 16:0 and relatively small percentages of very long-chain fatty acids as compared with clear lymph or plasma. The data are consistent with the view that in lymph chylomicrons: (a) cholesteryl esters are dissolved in a core of triglycerides which contain fatty acids derived primarily from dietary fatty acids, (b) free cholesterol is partitioned between core and surface and is freely exchangeable between the two, (c) the phospholipid fractions are present on the surface and are intracellular in origin. PMID:5640497

  2. Method of coating metal surfaces to form protective metal coating thereon

    DOEpatents

    Krikorian, Oscar H.; Curtis, Paul G.

    1992-01-01

    A process is disclosed for forming a protective metal coating on a metal surface using a flux consisting of an alkali metal fluoride, an alkaline earth metal fluoride, an alkali metal fluoaluminate, an alkali metal fluosilicate, and mixtures thereof. The flux, in particulate form, is mixed with particles of a metal coating material which may comprise aluminum, chromium, mixtures thereof, and alloys containing at least 50 wt. % aluminum and the particulate mixture is applied to the metal surface in a single step, followed by heating the coated metal surface to a temperature sufficient to cause the metal coating material to react with the metal surface to form a protective reaction product in the form of a metal coating bonded to the metal surface. The metal surface which reacts with the metal coating material to form the protective coating may comprise Fe, Co, Ni, Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, W, Re and alloys thereof.

  3. Method of coating metal surfaces to form protective metal coating thereon

    DOEpatents

    Krikorian, O.H.; Curtis, P.G.

    1992-03-31

    A process is disclosed for forming a protective metal coating on a metal surface using a flux consisting of an alkali metal fluoride, an alkaline earth metal fluoride, an alkali metal fluoaluminate, an alkali metal fluosilicate, and mixtures thereof. The flux, in particulate form, is mixed with particles of a metal coating material which may comprise aluminum, chromium, mixtures thereof, and alloys containing at least 50 wt. % aluminum and the particulate mixture is applied to the metal surface in a single step, followed by heating the coated metal surface to a temperature sufficient to cause the metal coating material to react with the metal surface to form a protective reaction product in the form of a metal coating bonded to the metal surface. The metal surface which reacts with the metal coating material to form the protective coating may comprise Fe, Co, Ni, Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, W, Re and alloys thereof. 1 figure.

  4. Plasma deposition of antimicrobial coating on organic polymer

    NASA Astrophysics Data System (ADS)

    Rżanek-Boroch, Zenobia; Dziadczyk, Paulina; Czajkowska, Danuta; Krawczyk, Krzysztof; Fabianowski, Wojciech

    2013-02-01

    Organic materials used for packing food products prevent the access of microorganisms or gases, like oxygen or water vapor. To prolong the stability of products, preservatives such as sulfur dioxide, sulfites, benzoates, nitrites and many other chemical compounds are used. To eliminate or limit the amount of preservatives added to food, so-called active packaging is sought for, which would limit the development of microorganisms. Such packaging can be achieved, among others, by plasma modification of a material to deposit on its surface substances inhibiting the growth of bacteria. In this work plasma modification was carried out in barrier discharge under atmospheric pressure. Sulfur dioxide or/and sodium oxide were used as the coating precursors. As a result of bacteriological studies it was found that sulfur containing coatings show a 16% inhibition of Salmonella bacteria growth and 8% inhibition of Staphylococcus aureus bacteria growth. Sodium containing coatings show worse (by 10%) inhibiting properties. Moreover, films with plasma deposited coatings show good sealing properties against water vapor. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  5. Introduction of Coating Technology of Superfine Particle Surface

    NASA Astrophysics Data System (ADS)

    Song, Jieguang; Zhang, Lianmeng; Li, Junguo; Song, Jianrong

    With the fast development of new materials investigation, attention is paid to. The performance of superfine powders, which must be modified on the surface to acquire some points. Coating technology of particles is one especial method of surface modification. In this paper, coating methods of particles are classified into solid state, liquid state, and gaseous state, main methods and mechanisms during current time are reviewed, respectively, and some research examples are listed. The choice of diversified coating technologies is decided synthetically based on powder materials, performance of the modified substance, and application of coated powders. In the future, the researches of the core-shell modification mechanism, coated particles with an ordered arrangement coating layer, a new surface active agent, the facilities of suiting surface modification, and the evaluation methodology of the surface coating effect are very exigent and necessary for the preparation and application of superfine powders.

  6. Surface treatment and surface coating of silicon field emitter array

    NASA Astrophysics Data System (ADS)

    Hajra, Mahua Sudhakrishna

    The objectives of this research were to fabricate ungated Si field emitter arrays (FEA's), and then to identify ways to improve the performance of the emitters. In the first and second chapters, the basis of the research, including background, theory, and the goals of the research is presented. The third chapter discusses the fabrication methods used to form the ungated Si FEA's. The fourth chapter gives the details about surface treatment procedures used to improve initial operation. The fifth and the sixth chapter discuss the different surface coating materials used to study the emission properties of the Si field emitters. The seventh chapter summarizes the work and suggests possible follow up research. The four surface treatments discussed in chapter four employ, respectively, residual gas ions, low-energy electron-stimulated desorption, a hydrogen-enhanced residual gas atmosphere, and a plasma of a Ar (96%) and H2 (4%) gas mixture. The method, using the hydrogen-enriched residual gas atmosphere is very unique in that it uses getters to produce the hydrogen rich atmosphere. The method, using a plasma of Ar (96%) and H2 (4%) gas mixture, is an effective in-situ cleaning procedure, which can be performed prior to packaging the devices. In chapters five and six is a comparison of the field-emission properties of the Si FEA coated with various materials, including (1) nanoparticle clusters of diamond and gallium nitride (GaN), (2) a thin film of ultrananocrystalline diamond (UNCD), (3) a lead zirconate titanate (PZT) coating, and (4) carbon nanotubes. Among the above coatings, the conformal coating of UNCD produced electron emission at an extremely low threshold field of between 2 to 5 V/mum. A further study of the behavior of electron emission from UNCD-coated Si FEA during in-situ exposure to H2, N2, and Ar respectively showed that when the emitting surface is exposed to H 2, at 10-5 Torr and 10-4 Torr, the initial emission current (2 muA) increases by a factor

  7. Polished substrate surface and cleaning study for coated optic quality

    SciTech Connect

    Tesar, A.; Eickelberg, W.; Koons, K.; Davis, K.

    1992-11-01

    The optical substrate-coating interface is established by (1) the original polished condition of the substrate; (2) the substrate cleaning process; and (3) the environment of the coating process. The substrate-coating interface affects the coating adhesion properties, is where most coating defects and scatter sites are thought to initiate, and in some instances may control the structure of the coating as it is deposited. Often features appear on an optic after coating which could not be observed after cleaning and prior to coating. Because of the wide variety of possible substrate materials, surface problems, and contaminants, cleaning processes are constantly evolving. Our study has clearly shown that the coating appearance is dependent not only on the cleaning method, but especially on the initial character of the substrate surface.

  8. Investigation of Surface Coatings on Silver Nanoparticles by Surface Enhanced Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kühn, Melanie; Ivleva, Natalia P.; Niessner, Reinhard; Baumann, Thomas

    2013-04-01

    The behavior of engineered inorganic nanoparticles (EINP) in the environment is strongly affected by their surface properties. Once introduced in the aquatic or terrestric environment, the nanoparticle surface may be altered by weathering or the formation of a coating. These changes influence the interactions of the nanoparticle with natural surfaces or interfaces as well as with other particles. Natural organic matter for example is known to have a stabilizing effect on most nanoparticles. Therefore the assessment of the fate and transport of nanoparticles in the environment requires a precise knowledge of the influence of the coating and its modifications under natural conditions. A suitable tool for the investigation of coatings on silver nanoparticles is surface enhanced Raman spectroscopy (SERS). Although silver nanoparticles themselves do not have a distinct Raman signal, the Raman signal of adsorbed or nearby substances is enhanced by a factor of 103 - 106. This leads to a considerably higher sensitivity of SERS in comparison to normal Raman microscopy. Therefore, coatings on silver nanoparticles should be accessible via the SERS effect. As a first step, plain and citrate stabilized silver nanoparticles were mixed with different natural coating substances (polygalacturonic acid, seaweed extract, and humic substances) and filtered with a polycarbonate filter to remove excessive coating material. Afterwards, the nanoparticles were redispersed from the filter by ultrasonification. This washing procedure was repeated three times while always maintaining the same concentration of nanoparticles. SERS spectra were recorded after each washing step with a LabRAM HR Raman mircospectrometer (Horiba Scientific, Japan, ? = 633 nm, 20x water-immersion-objective, measurement time 10 s). First results indicate the formation of a stabilizing layer around the nanoparticles after contact with humic substances, thus providing experimental evidence to the stabilization of EINP

  9. Fabrication and characterization of Mg-doped chitosan-gelatin nanocompound coatings for titanium surface functionalization.

    PubMed

    Cai, Xinjie; Cai, Jing; Ma, Kena; Huang, Pin; Gong, Lingling; Huang, Dan; Jiang, Tao; Wang, Yining

    2016-07-01

    Titanium and its alloys have been widely used in clinic and achieved great success. Due to the bio-inertness of titanium surface, challenges still exit in some compromised conditions. The present study aimed to functionalize titanium surface with magnesium (Mg)-doped chitosan/gelatin (CS/G) nanocompound coatings via electrophoretic deposition (EPD). CS/G coatings loaded with different amount of magnesium were successfully prepared on titanium substrate via EPD. Physicochemical characterization of the coatings confirmed that magnesium ions were loaded into the coatings in a dose-dependent manner. XRD results demonstrated that co-deposition of magnesium influenced the crystallinity of the coatings, and a new crystalline substance presented, namely hydrated basic magnesium carbonate. Mechanical tests showed improved tensile and shear bond strength of the magnesium-doped coatings, while the excessively high magnesium concentration could eventually decrease the bonding strength. Sustained release of magnesium ion was detected by ICP-OES within 28 days. TEM images also displayed that nanoparticles could be released from the coatings. In vitro cellular response assays demonstrated that the Mg-doped nanocompound coatings could enhance the proliferation and osteogenic differentiation of MC3T3-E1 cells compared to CS/G coatings. Therefore, it could be concluded that Mg-doped CS/G nanocompound coatings were successfully fabricated on titanium substrates via EPD. It would be a promising candidate to functionalize titanium surface with such organic-inorganic nanocompound coatings. PMID:27115206

  10. Chronic TiO2 nanoparticle exposure to a benthic organism, Hyalella azteca: Impact of solar UV radiation and material surface coatings on toxicity

    EPA Science Inventory

    The present study examined the chronic toxicity of TiO2 nanoparticles (nano-TiO2) to a representative benthic species, Hyalella azteca, using an industry standard, P25, and a coated nano-TiO2 used in commercial products. There is limited information on the chronic effects of nano...

  11. Multipurpose Polymeric Coating for Functionalizing Inert Polymer Surfaces.

    PubMed

    Özçam, A Evren; Efimenko, Kirill; Spontak, Richard J; Fischer, Daniel A; Genzer, Jan

    2016-03-01

    In this work, we report on the development of a highly functionalizable polymer coating prepared by the chemical coupling of trichlorosilane (TCS) to the vinyl groups of poly(vinylmethyl siloxane) (PVMS). The resultant PVMS-TCS copolymer can be coated as a functional organic primer layer on a variety of polymeric substrates, ranging from hydrophilic to hydrophobic. Several case studies demonstrating the remarkable and versatile properties of PVMS-TCS coatings are presented. In particular, PVMS-TCS is found to serve as a convenient precursor for the deposition of organosilanes and the subsequent growth of polymer brushes, even on hydrophobic surfaces, such as poly(ethylene terephthalate) and polypropylene. In this study, the physical and chemical characteristics of these versatile PVMS-TCS coatings are interrogated by an arsenal of experimental probes, including scanning electron microscopy, water contact-angle measurements, ellipsometry, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure spectroscopy. PMID:26814561

  12. Ex vivo surface and mechanical properties of coated orthodontic archwires.

    PubMed

    Elayyan, Firas; Silikas, Nick; Bearn, David

    2008-12-01

    This study examined the mechanical and physical properties of retrieved coated nickel-titanium (NiTi) archwires compared with unused samples. Ultraesthetic 0.016 inch coated archwires (G&H(R) Wire Company) were investigated. Ten as-received wires were subjected to a three-point bending test using conventional and self-ligating bracket systems. Surface roughness of the coating was measured with a contact stylus profilometer. Optical and scanning electron microscopes were used to assess surface topography. Ten archwires were used in vivo for a period of between 4 and 6 weeks. Retrieved archwires were subjected to the same tests. The percentage of the remaining coating was calculated using digital photography. Coated archwires were used in vivo for a mean period of 33 days. Differences between the mean values of the as-received and retrieved archwires were determined using t-tests. In the three-point bending test, with conventional elastomeric ligation, retrieved wires produced a lower unloading force (P < 0.001). Both retrieved and as-received coated archwires produced zero values of unloading force when deflected for 4 mm. When tested using a self-ligating bracket system, retrieved and as-received coated archwires produced the same amount of force (P > 0.05). With surface profilometry, all measured roughness parameters (except R(sm)) had greater surface roughness for the retrieved coated archwires (P < 0.05). Under microscopy, retrieved coated archwires showed discolouration, ditching, and delamination. Only 75 per cent of the coating was present in retrieved coated archwires. Retrieved coated archwires produced lower unloading force values than as-received coated archwires with conventional ligation. Surface roughness of coated archwires increased after use. Coated archwires have a low aesthetic value, with 25 per cent of the coating lost within 33 days in vivo. PMID:19011166

  13. Biomimetic surface coatings from modular amphiphilic proteins

    NASA Astrophysics Data System (ADS)

    Harden, James; Wan, Fan; Fischer, Stephen; Dick, Scott

    2010-03-01

    Recombinant DNA methods have been used to develop a library of diblock protein polymers for creating designer biofunctional interfaces. These proteins are composed of a surface-active, amphiphilic block joined to a disordered, water soluble block with an end terminal bioactive domain. The amphiphilic block has a strong affinity for many synthetic polymer surfaces, providing a facile means of imparting biological functionality to otherwise bio-neutral materials through physical self-assembly. We have incorporated a series of bioactive end domains into this diblock motif, including sequences that encode specific cell binding and signaling functions of extracellular matrix constituents (e.g. RGD and YIGSR). In this talk, we show that these diblock constructs self-assemble into biofunctional surface coatings on several model synthetic polymer materials. We demonstrate that surface adsorption of the proteins has minimal impacts on the presentation of the bioactive domains in the soluble block, and through the use of microscopic and cell proliferation assays, we show that the resulting biofunctional interfaces are capable of inducing appropriate cellular responses in a variety of human cell types.

  14. Nondestructive Analysis of Telescope Surfaces and Coatings

    NASA Astrophysics Data System (ADS)

    Scott, Julie; Kintzel, Edward; Strolger, Louis; Wolff, Schuyler

    2010-10-01

    The Department of Physics and Astronomy at Western Kentucky University has a Large Chamber Scanning Electron Microscope (LCSEM) available for materials analysis. As one of 10 in the world, the capability exists for nondestructive analysis of large samples. Currently we are investigating using the LCSEM to quantify reflectivity and long-term integrity for large segments of optical elements and detectors for ground and space-based environments. Comparisons of reflectance ratios as a function of surface roughness for Al-Coated optical mirrors may be confirmed with the LCSEM. Long-term structural integrity of Al-coated thinned mirror segments at ground-based facilities due to weather (oxidation) and spaced-based high-radiation environments can be investigated. Fatigue behavior of these metallic films from active/adaptive actuation will be simulated using the LCSEM. New research possibilities across a broad multidisciplinary spectrum will be key to the success of the LCSEM facility. These partnerships will lead to the development of new and existing technologies.

  15. Short-pulse laser removal of organic coatings

    NASA Astrophysics Data System (ADS)

    Walters, Craig T.

    2000-08-01

    A major problem in the regular maintenance of aerospace systems is the removal of paint and other protective coatings from surfaces without polluting the atmosphere or endangering workers. Recent research has demonstrated that many organic coatings can be removed from surfaces efficiently using short laser pulses without the use of any chemical agents. The lasers employed in this study were repetitively-pulsed neodymium YAG devices operating at 1064 nm (15 - 30 ns, 10 - 20 Hz). The efficiency of removal can be cast in terms of an effective heat of ablation, Q* (kJ of laser energy incident per g of paint removed), although, for short pulses, the mechanism of removal is believed to be dominated more by thermo- mechanical or shock effects than by photo-ablation. Q* data were collected as a function of pulse fluence for several paint types. For many paint types, there was a fairly sharp threshold fluence per pulse near 1 J/cm2, above which Q* values dropped to levels which were a factor of four lower than those observed for long- pulse or continuous laser ablation of paint. In this regime, the coating is removed in fairly large particles or, in the case of one paint, the entire thickness of the coating was removed over the exposed area in one pulse. Hardware for implementing short-pulse laser paint stripping in the field is under development and will be highlighted in the presentation. Practical paint stripping rates achieved using the prototype hardware are presented for several paint types.

  16. Mechanisms controlling adsorption of natural organic matter on surfactant-modified iron oxide-coated sand.

    PubMed

    Ding, Chunli; Shang, Chii

    2010-06-01

    Mechanisms contributing to the adsorption of natural organic matter (NOM) on surfactant-modified iron oxide-coated sand (IOCS) were explored by microscopic surface characterization techniques and adsorption tests. Electrostatic interactions that were thought to be from the positively charged, surface-coated surfactant, hexadecyltrimethyl ammonium (HDTMA), seemed to be unimportant, likely because the outward-pointing tail groups of the surface-coated HDTMA monolayers hindered the interactions. Improved hydrophobic interactions followed by ligand exchange are believed to be the dominant mechanisms. Atomic force microscopy (AFM) force analysis with chemically modified tips was used to explore the adsorption mechanisms between NOM and IOCS, where an iron oxide-coated mica surface was utilized as a substitute for the IOCS surface. It demonstrates the changes of pull-on forces and the increases in hydrophobic interactions from the modification of IOCS with HDTMA. PMID:20457463

  17. AC electrophoretic deposition of organic-inorganic composite coatings.

    PubMed

    Yoshioka, T; Chávez-Valdez, A; Roether, J A; Schubert, D W; Boccaccini, A R

    2013-02-15

    Alternating current electrophoretic deposition (AC-EPD) of polyacrylic acid (PAA)-titanium oxide (TiO(2)) nanoparticle composites on stainless steel electrodes was investigated in basic aqueous solution. AC square wave with duty cycle of 80% was applied at a frequency of 1 kHz. FTIR-ATR spectra showed that both AC and direct current (DC) EPD successfully deposited PAA-TiO(2) composites. The deposition rate using AC-EPD was lower than that obtained in direct current DC-EPD. However, the microstructure and surface morphology of the deposited composite coatings were different depending on the type of electric field applied. AC-EPD applied for not more than 5 min led to smooth films without bubble formation, while DC-EPD for 1 min or more showed deposits with microstructural defects possibly as result of water electrolysis. AC-EPD was thus for the first time demonstrated to be a suitable technique to deposit organic-inorganic composite coatings from aqueous suspensions, showing that applying a square wave and frequency of 1 kHz leads to uniform PAA-TiO(2) composite coatings on conductive materials. PMID:23218240

  18. Method and coating composition for protecting and decontaminating surfaces

    DOEpatents

    Overhold, D C; Peterson, M D

    1959-03-10

    A protective coating useful in the decontamination of surfaces exposed to radioactive substances is described. This coating is placed on the surface before use and is soluble in water, allowing its easy removal in the event decontamination becomes necessary. Suitable coating compositions may be prepared by mixing a water soluble carbohydrate such as sucrose or dextrin, together with a hygroscopic agent such as calcium chloride or zinc chloride.

  19. METHOD AND COATING COMPOSITION FOR PROTECTING AND DECONTAMINATING SURFACES

    DOEpatents

    Overhold, D.C.; Peterson, M.D.

    1959-03-10

    A protective coating useful in the decontamination of surfaces exposed to radioactive substances is presented. This coating is placed on the surface before use and is soluble in waters allowing its easy removal in the event decontamination becomes necessary. Suitable coating compositions may be prepared by mixing a water soluble carbohydrate such as sucrose or dextrin, together with a hygroscopic agent such as calcium chloride or zinc chloride.

  20. EVALUATION OF TOXICS IN RUNOFF FROM COATED SURFACES

    EPA Science Inventory

    Presented in this paper are results from a field and laboratory study of the potential runoff toxicity from coated surfaces. The study results qualified and quantified the types and concentrations of pollutants in runoff from surfaces sealed with a variety of products. Coatings a...

  1. High-Emissivity Coatings For High-Temperature Surfaces

    NASA Technical Reports Server (NTRS)

    Deininger, William D.; King, David Q.

    1988-01-01

    Plasma-sprayed coatings increase cooling by thermal radiation. Coating of zirconium diboride on tungsten or molybdenum increases emissivity of surface to more than 0.6 at 2,000 degree C. Applied by plasma-arc spraying after surface cleaned and roughened to ensure adhesion.

  2. Method of producing adherent metal oxide coatings on metallic surfaces

    DOEpatents

    Lane, Michael H.; Varrin, Jr., Robert D.

    2001-01-01

    Provided is a process of producing an adherent synthetic corrosion product (sludge) coating on metallic surfaces. The method involves a chemical reaction between a dry solid powder mixture of at least one reactive metal oxide with orthophosphoric acid to produce a coating in which the particles are bound together and the matrix is adherent to the metallic surface.

  3. Front surface thermal property measurements of air plasma spray coatings

    SciTech Connect

    Bennett, Ted; Kakuda, Tyler; Kulkarni, Anand

    2009-04-15

    A front-surface measurement for determining the thermal properties of thermal barrier coatings has been applied to air plasma spray coatings. The measurement is used to determine all independent thermal properties of the coating simultaneously. Furthermore, with minimal requirements placed on the sample and zero sample preparation, measurements can be made under previously impossible conditions, such as on serviceable engine parts. Previous application of this technique was limited to relatively thin coatings, where a one-dimensional heat transfer model is applied. In this paper, the influence of heat spreading on the measurement of thicker coatings is investigated with the development of a two-dimensional heat transfer model.

  4. Superhydrophobic Surface Coatings for Microfluidics and MEMs.

    SciTech Connect

    Branson, Eric D.; Singh, Seema; Houston, Jack E.; van Swol, Frank B.; Brinker, C. Jeffrey

    2006-11-01

    Low solid interfacial energy and fractally rough surface topography confer to Lotus plants superhydrophobic (SH) properties like high contact angles, rolling and bouncing of liquid droplets, and self-cleaning of particle contaminants. This project exploits the porous fractal structure of a novel, synthetic SH surface for aerosol collection, its self-cleaning properties for particle concentration, and its slippery nature 3 to enhance the performance of fluidic and MEMS devices. We propose to understand fundamentally the conditions needed to cause liquid droplets to roll rather than flow/slide on a surface and how this %22rolling transition%22 influences the boundary condition describing fluid flow in a pipe or micro-channel. Rolling of droplets is important for aerosol collection strategies because it allows trapped particles to be concentrated and transported in liquid droplets with no need for a pre-defined/micromachined fluidic architecture. The fluid/solid boundary condition is important because it governs flow resistance and rheology and establishes the fluid velocity profile. Although many research groups are exploring SH surfaces, our team is the first to unambiguously determine their effects on fluid flow and rheology. SH surfaces could impact all future SNL designs of collectors, fluidic devices, MEMS, and NEMS. Interfaced with inertial focusing aerosol collectors, SH surfaces would allow size-specific particle populations to be collected, concentrated, and transported to a fluidic interface without loss. In microfluidic systems, we expect to reduce the energy/power required to pump fluids and actuate MEMS. Plug-like (rather than parabolic) velocity profiles can greatly improve resolution of chip-based separations and enable unprecedented control of concentration profiles and residence times in fluidic-based micro-reactors. Patterned SH/hydrophilic channels could induce mixing in microchannels and enable development of microflow control elements

  5. Plasma-Sprayed Coatings on Porous Surfaces

    NASA Technical Reports Server (NTRS)

    Leibert, C. H.

    1986-01-01

    Need for combining benefits of duplex thermal-barrier coatings with film cooling on gas-turbine vanes and blades stimulated development of improved method for plasma spraying these coatings. Method reduces blocking of holes by plasma-sprayed material and at same time reduces base-metal oxidation during coating operation. Features provide potential for increased engine efficiency and power, reduced fuel consumption, use of less costly materials or construction procedures, and extended life and durability.

  6. Antibacterial activity of plastics coated with silver-doped organic-inorganic hybrid coatings prepared by sol-gel processes.

    PubMed

    Marini, M; De Niederhausern, S; Iseppi, R; Bondi, M; Sabia, C; Toselli, M; Pilati, F

    2007-04-01

    Silver-doped organic-inorganic hybrid coatings were prepared starting from tetraethoxysilane- and triethoxysilane-terminated poly(ethylene glycol)-block-polyethylene by the sol-gel process. They were applied as a thin layer (0.6-1.1 microm) to polyethylene (PE) and poly(vinyl chloride) (PVC) films and the antibacterial activity of the coated films was tested against Gram-negative (Escherichia coli ATCC 25922) and Gram-positive (Staphylococcus aureus ATCC 6538) bacteria. The effect of several factors (such as organic-inorganic ratio, type of catalyst, time of post-curing, silver ion concentration, etc.) was investigated. Measurements at different contact times showed a rapid decrease of the viable count for both tested strains. The highest antibacterial activity [more than 6 log reduction within 6 h starting from 106 colony-forming units (cfu) mL-1] was obtained for samples with an organic-inorganic weight ratio of 80:20 and 5 wt % silver salt with respect to the coating. For the coatings prepared by an acid-catalyzed process, a high level of permanence of the antibacterial activity of the coated films was demonstrated by repeatedly washing the samples in warm water or by immersion in physiological saline solution at 37 degrees C for 3 days. The release of silver ions per square meter of coating is very similar to that previously observed for polyamides filled with metallic silver nanoparticles; however, when compared on the basis of Ag content, the concentration of silver ions released from the coating is much higher than that released from 1 mm thick specimens of polyamide (PA) filled with silver nanoparticles. Transparency and good adhesion of the coating to PE and PVC plastic substrates without any previous surface treatment are further interesting features. PMID:17335284

  7. Size-Controlled Dissolution of Organic-Coated Silver Nanoparticles

    SciTech Connect

    Ma, Rui; Levard, Clément; Marinakos, Stella M.; Cheng, Yingwen; Liu, Jie; Michel, F. Marc; Brown, Jr., Gordon E.; Lowry, Gregory V.

    2012-04-02

    The solubility of Ag NPs can affect their toxicity and persistence in the environment. We measured the solubility of organic-coated silver nanoparticles (Ag NPs) having particle diameters ranging from 5 to 80 nm that were synthesized using various methods, and with different organic polymer coatings including poly(vinylpyrrolidone) and gum arabic. The size and morphology of Ag NPs were characterized by transmission electron microscopy (TEM). X-ray absorption fine structure (XAFS) spectroscopy and synchrotron-based total X-ray scattering and pair distribution function (PDF) analysis were used to determine the local structure around Ag and evaluate changes in crystal lattice parameters and structure as a function of NP size. Ag NP solubility dispersed in 1 mM NaHCO{sub 3} at pH 8 was found to be well correlated with particle size based on the distribution of measured TEM sizes as predicted by the modified Kelvin equation. Solubility of Ag NPs was not affected by the synthesis method and coating as much as by their size. Based on the modified Kelvin equation, the surface tension of Ag NPs was found to be {approx}1 J/m{sup 2}, which is expected for bulk fcc (face centered cubic) silver. Analysis of XAFS, X-ray scattering, and PDFs confirm that the lattice parameter, {alpha}, of the fcc crystal structure of Ag NPs did not change with particle size for Ag NPs as small as 6 nm, indicating the absence of lattice strain. These results are consistent with the finding that Ag NP solubility can be estimated based on TEM-derived particle size using the modified Kelvin equation for particles in the size range of 5-40 nm in diameter.

  8. Surface characteristics of a novel hydroxyapatite-coated dental implant

    PubMed Central

    Jung, Ui-Won; Hwang, Ji-Wan; Choi, Da-Yae; Hu, Kyung-Seok; Kwon, Mi-Kyung; Choi, Seong-Ho

    2012-01-01

    Purpose This study evaluated the surface characteristics and bond strength produced using a novel technique for coating hydroxyapatite (HA) onto titanium implants. Methods HA was coated on the titanium implant surface using a super-high-speed (SHS) blasting method with highly purified HA. The coating was performed at a low temperature, unlike conventional HA coating methods. Coating thickness was measured. The novel HA-coated disc was fabricated. X-ray diffraction analysis was performed directly on the disc to evaluate crystallinity. Four novel HA-coated discs and four resorbable blast medium (RBM) discs were prepared. Their surface roughnesses and areas were measured. Five puretitanium, RBM-treated, and novel HA-coated discs were prepared. Contact angle was measured. Two-way analysis of variance and the post-hoc Scheffe's test were used to analyze differences between the groups, with those with a probability of P<0.05 considered to be statistically significant. To evaluate exfoliation of the coating layer, 7 sites on the mandibles from 7 mongrel dogs were used. Other sites were used for another research project. In total, seven novel HA-coated implants were placed 2 months after extraction of premolars according to the manufacturer's instructions. The dogs were sacrificed 8 weeks after implant surgery. Implants were removed using a ratchet driver. The surface of the retrieved implants was evaluated microscopically. Results A uniform HA coating layer was formed on the titanium implants with no deformation of the RBM titanium surface microtexture when an SHS blasting method was used. Conclusions These HA-coated implants exhibited increased roughness, crystallinity, and wettability when compared with RBM implants. PMID:22586524

  9. Antisoiling technology: Theories of surface soiling and performance of antisoiling surface coatings

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Willis, P. B.

    1984-01-01

    Physical examination of surfaces undergoing natural outdoor soiling suggests that soil matter accumulates in up to three distinct layers. The first layer involves strong chemical attachment or strong chemisorption of soil matter on the primary surface. The second layer is physical, consisting of a highly organized arrangement of soil creating a gradation in surface energy from a high associated with the energetic first layer to the lowest possible state on the outer surfce of the second layer. The lowest possible energy state is dictated by the physical nature of the regional atmospheric soiling materials. These first two layers are resistant to removal by rain. The third layer constitutes a settling of loose soil matter, accumulating in dry periods and being removed during rainy periods. Theories and evidence suggest that surfaces that should be naturally resistant to the formation of the first two-resistant layers should be hard, smooth, hydrophobic, free of first-period elements, and have the lowest possible surface energy. These characteristics, evolving as requirements for low-soiling surfaces, suggest that surfaces or surface coatings should be of fluorocarbon chemistry. Evidence for the three-soil-layer concept, and data on the positive performance of candidate fluorocarbon coatings on glass and transparent plastic films after 28 months of outdoor exposure, are presented.

  10. Water-repellent coatings for surface and 3D wood processing

    NASA Astrophysics Data System (ADS)

    Debelova, N. N.; Gorlenko, N. P.; Volokitin, G. G.; Sarkisov, Yu S.; Dmitriyenko, V. P.; Zavyalova, E. N.; Zavyalov, P. B.

    2015-01-01

    The paper presents the results of research in organic chemical compositions for hydrophobic protection of wood with the use of surface and three-dimensional coating techniques of impregnation and chemical compositions. Water absorption indicators, angles of contact on the surface of treated samples are detected herein. Kinetic equation of the moisture diffusion transition in capillary-porous structure of wood is suggested.

  11. Self-healing antimicrobial polymer coating with efficacy in the presence of organic matter

    NASA Astrophysics Data System (ADS)

    Bastarrachea, Luis J.; Goddard, Julie M.

    2016-08-01

    A method to prepare a self-healing, antimicrobial polymer coating that retains efficacy against Escherichia coli O157:H7 in the presence of organic matter is reported. A coating composed of branched polyethyleneimine (PEI) and styrene maleic anhydride copolymer (SMA) was applied to a maleic anhydride functionalized polypropylene support. The chemistry of the polymer coating was designed to impart hydrophobicity due to the styrene subunits, intrinsic antimicrobial character (>99.9% reduction) from the cationic primary amine groups, and enhanced antimicrobial character (> 99.99% reduction) after chlorination of N-halamine forming groups. Antimicrobial effectiveness was demonstrated under conditions of increasing organic load. Up to 500 ppm horse serum, chlorinated coatings retained full antimicrobial character (>99.99% reduction). Even at 50,000 ppm of horse serum, the coating provided ∼90% reduction as prepared, and between ∼75% and ∼80% reduction in the form of N-halamines. Microscopy confirmed no evidence of bacterial adhesion on the coating surface. Finally, the coating exhibited self-healing properties after exposure to acid and alkaline solutions and restoration by heat, as confirmed through spectroscopy from the rebuilding of characteristic chemical bonds. Such robust antimicrobial polymer coatings with efficacy under conditions of increasing organic load may support reducing microbial cross-contamination in food and biomedical industries.

  12. Surface coating effects in remote sensing measurements

    USGS Publications Warehouse

    Watson, Robert D.

    1970-01-01

    Measurements of the infrared spectra of a liquid-(water) coated quartz substrate and a solid-(pyrophyllite) coated quartzite are compared to theoretical values. Results demonstrate that in the case of the water-coated quartz, a loss in spectral contrast of the quartz emission occurs at the principal restrahlen wavelengths of 8.5, 9.0, and 12.5 µ but is most pronounced at 12.5 µ. In the case of pyrophyllite-coated quartzite, additional spectral features appear between 8.0 and 10.0 µ as the exposure of quartzite through the pyrophyllite coating is increased. Addition of the pure quartzite and pyrophyllite spectra, weighted by exposed area, is shown to satisfactorily describe the composite spectra.

  13. Mechanism of formation of humus coatings on mineral surfaces 2. Attenuated total reflectance spectra of hydrophobic and hydrophilic fractions of organic acids from compost leachate on alumina

    USGS Publications Warehouse

    Wershaw, R. L.; Llaguno, E.C.; Leenheer, J.A.; Sperline, R.P.; Song, Y.

    1996-01-01

    Hydrophobic and hydrophilic fractions were isolated from a compost leachate. The adsorption isotherms of both fractions on alumina were measured by attenuated total reflectance infrared spectroscopy. The shapes of the adsorption isotherms of the two fractions were different. The isotherms for the hydrophilic fraction showed little change in surface excess with increasing solution concentration above 4 mg L-1. The isotherms for the hydrophobic fraction, on the other hand, displayed a marked increase in surface excess with increasing solution concentration. This increase is evidence for the formation of aggregates (admicelles or hemimicelles) on the alumina surface. Linear dichroism calculations indicated that more of the carboxylate groups in the adsorbed hydrophobic molecules than in the absorbed hydrophilic fraction were free to rotate. The hindered rotation of the carboxylate groups in the adsorbed hydrophilic-fraction molecules probably indicates that these groups are bound to surface aluminum ions by a bidentate mechanism in which the two oxygen atoms of a single carboxylate group bind to separate aluminum ions.

  14. Self-assembled hemocompatible coating on poly (vinyl chloride) surface

    NASA Astrophysics Data System (ADS)

    Zha, Zhengbao; Ma, Yan; Yue, Xiuli; Liu, Meng; Dai, Zhifei

    2009-11-01

    A stable hemocompatible coating was fabricated by consecutive alternating adsorption of iron (III) and two kinds of polysaccharides, heparin (Hep) and dextran sulfate (DS), onto poly (vinyl chloride) (PVC) surfaces via electrostatic interaction. The fluctuation of contact angles with the alternative deposition of iron (III) and polysaccharides verified the progressive buildup of the mulitilayer coating onto the PVC surface. Atomic force microscopy (AFM) analysis revealed that the PVC surfaces were completely masked by iron-polysaccharides multilayer coatings. The activated partial thromboplastin time (APTT) assay showed that both Hep/Fe 3+/Hep and DS/Fe 3+/Hep coated PVC were less thrombogenic than the uncoated one. Chromogenic assay for heparin activity proved definitively that the inhibition of locally produced thrombin was ascribed to the thromboresistance of the surface-bound heparin. Compared with the unmodified PVC surfaces, iron-polysaccharide multilayer coating presented a drastically reduced adhesion in vitro of platelets, polymorphonuclear neutrophil leukocytes (PMN) and peripheral blood mononuclear cells (PBMC). Interestingly, the DS/Fe 3+/Hep coating was found to exhibit higher hydrophilicity and stability, hence lower non-specific protein adsorption in comparison with Hep/Fe 3+/Hep coating due to the incorporation of dextran sulfate into the multilayer coating.

  15. Particle size, surface coating, and PEGylation influence the biodistribution of quantum dots in living mice.

    PubMed

    Schipper, Meike L; Iyer, Gopal; Koh, Ai Leen; Cheng, Zhen; Ebenstein, Yuval; Aharoni, Assaf; Keren, Shay; Bentolila, Laurent A; Li, Jianquing; Rao, Jianghong; Chen, Xiaoyuan; Banin, Uri; Wu, Anna M; Sinclair, Robert; Weiss, Shimon; Gambhir, Sanjiv S

    2009-01-01

    This study evaluates the influence of particle size, PEGylation, and surface coating on the quantitative biodistribution of near-infrared-emitting quantum dots (QDs) in mice. Polymer- or peptide-coated 64Cu-labeled QDs 2 or 12 nm in diameter, with or without polyethylene glycol (PEG) of molecular weight 2000, are studied by serial micropositron emission tomography imaging and region-of-interest analysis, as well as transmission electron microscopy and inductively coupled plasma mass spectrometry. PEGylation and peptide coating slow QD uptake into the organs of the reticuloendothelial system (RES), liver and spleen, by a factor of 6-9 and 2-3, respectively. Small particles are in part renally excreted. Peptide-coated particles are cleared from liver faster than physical decay alone would suggest. Renal excretion of small QDs and slowing of RES clearance by PEGylation or peptide surface coating are encouraging steps toward the use of modified QDs for imaging living subjects. PMID:19051182

  16. Deposition Kinetics of Bioinspired Phenolic Coatings on Titanium Surfaces.

    PubMed

    Geißler, Sebastian; Barrantes, Alejandro; Tengvall, Pentti; Messersmith, Phillip B; Tiainen, Hanna

    2016-08-16

    Polyphenols can form functional coatings on a variety of different materials through auto-oxidative surface polymerization in a manner similar to polydopamine coatings. However, the mechanisms behind the coating deposition are poorly understood. We report the coating deposition kinetics of the polyphenol tannic acid (TA) and the simple phenolic compound pyrogallol (PG) on titanium surfaces. The coating deposition was followed in real time over a period of 24 h using a quartz crystal microbalance with dissipation monitoring (QCM-D). TA coatings revealed a multiphasic layer formation: the deposition of an initial rigid layer was followed by the buildup of an increasingly dissipative layer, before mass adsorption stopped after approximately 5 h of coating time. The PG deposition was biphasic, starting with the adsorption of a nonrigid viscoelastic layer which was followed by layer stiffening upon further mass adsorption. Coating evaluation by ellipsometry and AFM confirmed the deposition kinetics determined by QCM-D and revealed maximum coating thicknesses of approximately 50 and 75 nm for TA and PG, respectively. Chemical characterization of the coatings and polymerized polyphenol particles indicated the involvement of both physical and chemical interactions in the auto-oxidation reactions. PMID:27452793

  17. On the wettability transparency of graphene-coated silicon surfaces

    NASA Astrophysics Data System (ADS)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.

    2016-01-01

    In order to better understand the behavior and governing characteristics of the wetting transparency phenomenon observed in graphene-coated surfaces, molecular dynamics simulations were coupled with a theoretical model. Graphene-coated silicon was selected for this analysis, due to potential applications of hybrid silicon-graphene materials as detectors in aqueous environments. The results indicate good agreement between the theory and simulations at the macroscopic conditions required to observe wetting transparency. A microscopic analysis was also conducted in order to identify the parameters, such as the interaction potential energy landscape and the interfacial liquid structure that govern the wetting behavior of graphene-coated surfaces. The interfacial liquid structure was found to be different between uncoated Si(100) and the graphene-coated version and very similar between uncoated Si(111) and the graphene-coated version. However, the concentration of liquid particles for both silicon surfaces was found to be very similar under transparent wetting conditions.

  18. Surface modification and characterization of aramid fibers with hybrid coating

    NASA Astrophysics Data System (ADS)

    Chen, Jianrui; Zhu, Yaofeng; Ni, Qingqing; Fu, Yaqin; Fu, Xiang

    2014-12-01

    Aramid fibers were modified through solution dip-coating and interfacial in situ polymerization using a newly synthesized SiO2/shape memory polyurethane (SiO2/SMPU) hybrid. Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the synthesized SiO2/SMPU hybrid successfully coated the fiber surface. The surface morphology of the aramid fibers and the single fiber tensile strength and interfacial shear strength (IFSS) of the composites were determined. The IFSS of the fiber coated with the hybrid improved by 45%, which benefited from a special "pizza-like" structure on the fiber surface.

  19. APPLICATION OF HYDROPHILIC STARCH-BASED COATINGS TO POLYETHYLENE SURFACES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coatings were applied to polyethylene film surfaces by spraying formulations prepared from a jet cooked dispersion of waxy cornstarch, a water-based epoxy resin, a wax emulsion, and a surfactant. Although the starch component separated rapidly from the coating when the film was placed in water at r...

  20. Sprayable birefringent coating enables strain measurements on large surfaces

    NASA Technical Reports Server (NTRS)

    Humphrey, F. T.; Mcgee, W. M.

    1966-01-01

    Birefringent coating for strain measurements on large surfaces contains constituents that can be premixed and sprayed as a single component with conventional paint spray equipment. Elevated temperatures are not required for spraying or curing of the coating material which has long pot life.

  1. Frost resistance of concrete surfaces coated with waterproofing materials

    NASA Astrophysics Data System (ADS)

    Klovas, A.; Dauksys, M.; Ciuprovaite, G.

    2015-03-01

    Present research lays emphasis on the problem of concrete surface exposed to aggressive surrounding quality. The test was conducted with concrete surfaces coated with different waterproofing materials exposed in solution of 3 % of sodium sulphate. Research was performed according to LST EN 1338:2003 standard requirements. Technological properties of concrete mixture as well as physical-mechanical properties of formed concrete specimens were established. The resistance of concrete to freezing - thawing cycles was prognosticated according to the porosity parameters established by the kinetic of water absorption. Five different waterproofing materials (coatings) such as liquid bitumen-rubber based, elastic fiber-strengthened, silane-siloxane based emulsion, mineral binder based and liquid rubber (caoutchouc) based coatings were used. Losses by mass of coating materials and specimens surface fractures were calculated based on the results of frost resistance test. Open code program "ImageJ" was used for visual analysis of concrete specimens. Based on the results, aggressive surrounding did not influence specimens coated with elastic, fibre-strengthened, mineral materials. On the other hand, specimens coated with liquid rubber (caoutchouc) based material were greatly influenced by aggressive surrounding. The biggest losses of specimen surface concrete (fractures) were obtained with silane-siloxane based emulsion coating. Generally, specimens coated with waterproofing materials were less influenced by aggressive surrounding compared with those without.

  2. Aircraft surface coatings study: Energy efficient transport program. [sprayed and adhesive bonded coatings for drag reduction

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Surface coating materials for application on transport type aircraft to reduce drag, were investigated. The investigation included two basic types of materials: spray on coatings and adhesively bonded films. A cost/benefits analysis was performed, and recommendations were made for future work toward the application of this technology.

  3. Possibilities of surface coating for thermal insulation. [zirconium dioxide, titanium dioxide, and zircon coatings

    NASA Technical Reports Server (NTRS)

    Poeschel, E.; Weisser, G.

    1979-01-01

    Calculations performed for pulsating heat sources indicate a relatively thin (200-1000 micron) coating can lower temperature both inside and on the surface of a construction material. Various coating materials (including zirconium dioxide) are discussed, together with possible thermic stresses and ways to deal with the latter.

  4. Electromagnetic properties of ice coated surfaces

    NASA Technical Reports Server (NTRS)

    Dominek, A.; Walton, E.; Wang, N.; Beard, L.

    1989-01-01

    The electromagnetic scattering from ice coated structures is examined. The influence of ice is shown from a measurement standpoint and related to a simple analytical model. A hardware system for the realistic measurement of ice coated structures is also being developed to use in an existing NASA Lewis icing tunnel. Presently, initial measurements have been performed with a simulated tunnel to aid in the development.

  5. Instruments Sniff Organic Surface Contaminants

    NASA Technical Reports Server (NTRS)

    Adler-Golden, Steven; Matthew, Michael W.

    1995-01-01

    Portable instruments detecting both nonvolatile and volatile organic surface contaminants in real time developed. Instruments easy to use: operate under ordinary ambient atmospheric conditions, without need to use messy liquid solvents or install and remove witness plates, and without need to cut specimens from surfaces to be inspected. Principle of detection involves sweeping pure, activated gas across surface spot inspected, then monitoring light emitted at wavelengths characteristic of excited molecules formed by chemical reactions between activated gas and contaminants. Gas activated by dc discharge, radio-frequency induction, microwave radiation, laser beam, hot filaments, or any other suitable means that excites some of gas molecules.

  6. Evaluation of volatile organic compound reduction technologies for metal coatings

    SciTech Connect

    Wang, Y.; Huang, E.W.

    1997-12-31

    Under the sponsorship of California Air Resources Board, AeroVironment Environmental Services, Inc. (AVES) is currently conducting a study to demonstrate a new zero-VOC Industrial Maintenance Metal Coating. This new technology can help the coating industry reduce emissions of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs). In a previous study conducted by AVES, current VOCs technologies available on the market for metal parts and product coatings were evaluated for compliance with the South Coast Air Quality Management District (SCAQMD) proposed Rule 1107 (Metal Parts and Product Coatings). There are low-VOC coating products available for industries of interest. For general metal coating applications, certain coating products can comply with current SCAQMD Rule 1107 VOC limits. Some of the low-VOC products that are considered as a substitute or an alternative to high-VOC petroleum-based products are summarized. The current available emerging technologies offer a great opportunity for emission reduction through a gradual shift from high to low/no VOC coatings. By phasing in low/no VOC coatings, industries will be able to reduce energy use and air emissions without installation of add-on controls.

  7. Front surface passivation of silicon solar cells with antireflection coating

    NASA Technical Reports Server (NTRS)

    Crotty, G.; Daud, T.; Kachare, R.

    1987-01-01

    It is demonstrated that the deposition and postdeposition sintering of an antireflection (AR) coating in hydrogen acts to passivate silicon solar cells. Cells with and without an SiO2 passivating layer, coated with a TiO(x)/Al2O3 AR coating, showed comparable enhancements in short-wavelength spectral response and in open-circuit voltage Voc after sintering at 400 C for 5 min in a hydrogen ambient. The improvement in Voc of cells without SiO2 is attributed to front-surface passivation by the AR coating during processing.

  8. Surface coating for prevention of metallic seed migration in tissues

    SciTech Connect

    Lee, Hyunseok; Park, Jong In; Lee, Won Seok; Park, Min; Son, Kwang-Jae; Bang, Young-bong; Choy, Young Bin E-mail: sye@snu.ac.kr; Ye, Sung-Joon E-mail: sye@snu.ac.kr

    2015-06-15

    Purpose: In radiotherapy, metallic implants often detach from their deposited sites and migrate to other locations. This undesirable migration could cause inadequate dose coverage for permanent brachytherapy and difficulties in image-guided radiation delivery for patients. To prevent migration of implanted seeds, the authors propose a potential strategy to use a biocompatible and tissue-adhesive material called polydopamine. Methods: In this study, nonradioactive dummy seeds that have the same geometry and composition as commercial I-125 seeds were coated in polydopamine. Using scanning electron microscopy and x-ray photoelectron spectroscopy, the surface of the polydopamine-coated and noncoated seeds was characterized. The detachment stress between the two types of seeds and the tissue was measured. The efficacy of polydopamine-coated seed was investigated through in vitro migration tests by tracing the seed location after tissue implantation and shaking for given times. The cytotoxicity of the polydopamine coating was also evaluated. Results: The results of the coating characterization have shown that polydopamine was successfully coated on the surface of the seeds. In the adhesion test, the polydopamine-coated seeds had 2.1-fold greater detachment stress than noncoated seeds. From the in vitro test, it was determined that the polydopamine-coated seed migrated shorter distances than the noncoated seed. This difference was increased with a greater length of time after implantation. Conclusions: The authors suggest that polydopamine coating is an effective technique to prevent migration of implanted seeds, especially for permanent prostate brachytherapy.

  9. Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces

    NASA Technical Reports Server (NTRS)

    Dussinger, Peter M.; Lindemuth, James E.

    1997-01-01

    The principal objective of this Phase 2 SBIR program was to develop and demonstrate a practically insoluble coating for nickel-based superalloys for Stirling engine heat pipe applications. Specific technical objectives of the program were: (1) Determine the solubility corrosion rates for Nickel 200, Inconel 718, and Udimet 72OLI in a simulated Stirling engine heat pipe environment, (2) Develop coating processes and techniques for capillary groove and screen wick structures, (3) Evaluate the durability and solubility corrosion rates for capillary groove and screen wick structures coated with an insoluble coating in cylindrical heat pipes operating under Stirling engine conditions, and (4) Design and fabricate a coated full-scale, partial segment of the current Stirling engine heat pipe for the Stirling Space Power Convertor program. The work effort successfully demonstrated a two-step nickel aluminide coating process for groove wick structures and interior wall surfaces in contact with liquid metals; demonstrated a one-step nickel aluminide coating process for nickel screen wick structures; and developed and demonstrated a two-step aluminum-to-nickel aluminide coating process for nickel screen wick structures. In addition, the full-scale, partial segment was fabricated and the interior surfaces and wick structures were coated. The heat pipe was charged with sodium, processed, and scheduled to be life tested for up to ten years as a Phase 3 effort.

  10. Radiative cooling: lattice quantization and surface emissivity in thin coatings.

    PubMed

    Suryawanshi, Chetan N; Lin, Chhiu-Tsu

    2009-06-01

    Nanodiamond powder (NDP), multiwall carbon nanotube (MWCNT), and carbon black (CB) were dispersed in an acrylate (AC) emulsion to form composite materials. These materials were coated on aluminum panels (alloy 3003) to give thin coatings. The active phonons of the nanomaterials were designed to act as a cooling fan, termed "molecular fan (MF)". The order of lattice quantization, as investigated by Raman spectroscopy, is MWCNT > CB > NDP. The enhanced surface emissivity of the MF coating (as observed by IR imaging) is well-correlated to lattice quantization, resulting in a better cooling performance by the MWCNT-AC composite. MF coatings with different concentrations (0%, 0.4%, 0.7%, and 1%) of MWCNT were prepared. The equilibrium temperature lowering of the coated panel was observed with an increase in the loading of CNTs and was measured as 17 degrees C for 1% loading of MWCNT. This was attributed to an increased density of active phonons in the MF coating. PMID:20355930

  11. Surface characterization of hot-dip Galfan coatings

    SciTech Connect

    Bluni, S.T.; Marder, A.R.; Goldstein, J.I. . Materials Science Engineering Dept.)

    1994-09-01

    The surface of a hot dipped Galfan (Zn-5wt.%Al-mischmetal) coating on sheet steel was characterized with the use of various microscopy techniques. Surface depressions, or dents, were found to occur at eutectic nodule boundaries and triple points, and were typically 10--15 [mu]m deep. The surface characteristics of the Galfan coating were reproduced by the solidification of Zn-5%Al-mischmetal alloy samples on an inert substrate, implying that surface depressions are not caused by substrate interactions. Chemical analyses of both the coating and the alloy samples indicate that impurities, particularly lead, are strongly segregated to eutectic nodule boundaries and triple points. Based on these observations, a mechanism for denting and cracking in Galfan coatings is suggested.

  12. POLLUTION PREVENTION METHODS IN THE SURFACE COATING INDUSTRY

    EPA Science Inventory

    The surface coating industry is rapidly changing to meet environmental and economic pressures. Some of the changes include new formulations which meet environmental regulations, higher performance finishes with improved properties, continued development of solventless technologie...

  13. 45S5 Bioglass®-derived scaffolds coated with organic-inorganic hybrids containing graphene.

    PubMed

    Fabbri, Paola; Valentini, Luca; Hum, Jasmin; Detsch, Rainer; Boccaccini, Aldo R

    2013-10-01

    Highly porous 45S5 Bioglass®-based scaffolds fabricated by a foam replication technique were coated with electrically conductive organic-inorganic hybrid layers containing graphene by a solution method. α,ω-Triethoxysilane terminated poly (ethylene glycol) and tetraethoxysilane were used as the precursors of the organic-inorganic hybrid coatings, that contained 1.5 wt.% of homogeneously dispersed graphene nanoplatelets. The resulting coated scaffolds retained their original high porosity and interconnected pore structure after coating. The presence of graphene did not impair the bioactivity of the scaffolds in simulated body fluid. Initial tests carried out using MG-63 cells demonstrated that both uncoated scaffolds and scaffolds coated with organic/inorganic hybrids containing graphene offered the cultured cells an adequate surface for cell attachment, spreading and expression of extracellular matrix. The results showed that scaffolds coated with graphene are biocompatible and they can support cellular activity. The electrical conductivity introduced by the coating might have the potential to increase tissue growth when cell culture is carried out under an applied electric field. PMID:23910254

  14. Zwitteration: Coating Surfaces with Zwitterionic Functionality to Reduce Nonspecific Adsorption

    PubMed Central

    2015-01-01

    Coating surfaces with thin or thick films of zwitterionic material is an effective way to reduce or eliminate nonspecific adsorption to the solid/liquid interface. This review tracks the various approaches to zwitteration, such as monolayer assemblies and polymeric brush coatings, on micro- to macroscopic surfaces. A critical summary of the mechanisms responsible for antifouling shows how zwitterions are ideally suited to this task. PMID:24754399

  15. Corrosion Resistance of Friction Surfaced AISI 304 Stainless Steel Coatings

    NASA Astrophysics Data System (ADS)

    Khalid Rafi, H.; Phanikumar, G.; Prasad Rao, K.

    2013-02-01

    Corrosion resistance of friction surfaced AISI 304 coating in boiling nitric acid and chloride containing environments was found to be similar to that of its consumable rod counterpart. This was in contrast to the autogenous fusion zone of GTAW weld which showed inferior corrosion resistance with respect to the consumable rod. The superior corrosion resistance of friction surfaced coatings was attributed to the absence of δ-ferrite in it.

  16. Bone regeneration associated with nontherapeutic and therapeutic surface coatings for dental implants in osteoporosis.

    PubMed

    Alghamdi, Hamdan S; Jansen, John A

    2013-06-01

    Oral implantology is considered as the treatment of choice for replacing missing teeth in elderly people. However, implant complications may occur in patients with osteoporosis. The pathogenesis underlying osteoporosis is due to an alteration in bone cell response to hormonal, nutritional, and aging factors. For such challenging situations, improved bone regeneration has been shown around dental implants for certain surface modifications. These modifications include coatings of titanium implants with calcium phosphate (CaP) ceramics. Surface coating developments also allow for the addition of organic biomolecules, like growth factors, into the inorganic coatings that increase the bone formation process at the bone-implant interface. The application of therapeutic-based coatings is becoming a rapidly growing research field of interest. CaP-coated implants have the ability to incorporate anti-osteoporotic drugs, which then can be locally released over time from an implant surface in a controlled manner. Thus, it can be anticipated that nontherapeutic and/or therapeutic coated implants can significantly increase low bone density as well as improve impaired bone regeneration in osteoporosis. This review aims to provide a thorough understanding of the underlying mechanisms for impaired bone regeneration around dental implants in osteoporosis. Secondly, the review will focus on biological interactions and beneficial role of the surface-coated (i.e., nontherapeutics and therapeutics) bone implants in osteoporotic bone tissue. PMID:23088597

  17. Modification of Surface Layers by Surfacing Intermetallic Coatings with Variable Properties

    NASA Astrophysics Data System (ADS)

    Makeev, D. N.; Zakharov, O. V.; Vinogradov, A. N.; Kochetkov, A. V.

    2016-02-01

    The paper considers the possibility of forming coating layers for parts within wide limits of microhardness. The technology uses surfacing of intermetallic coatings provided by a unique experimental setup. Theoretical and experimental dependence of the coating layer microhardness on the filler concentration using the changes in the speed of the filler wire feed and current intensity were determined.

  18. Inorganic-organic thin implant coatings deposited by lasers.

    PubMed

    Sima, Felix; Davidson, Patricia M; Dentzer, Joseph; Gadiou, Roger; Pauthe, Emmanuel; Gallet, Olivier; Mihailescu, Ion N; Anselme, Karine

    2015-01-14

    The lifetime of bone implants inside the human body is directly related to their osseointegration. Ideally, future materials should be inspired by human tissues and provide the material structure-function relationship from which synthetic advanced biomimetic materials capable of replacing, repairing, or regenerating human tissues can be produced. This work describes the development of biomimetic thin coatings on titanium implants to improve implant osseointegration. The assembly of an inorganic-organic biomimetic structure by UV laser pulses is reported. The structure consists of a hydroxyapatite (HA) film grown onto a titanium substrate by pulsed-laser deposition (PLD) and activated by a top fibronectin (FN) coating deposited by matrix-assisted pulsed laser evaporation (MAPLE). A pulsed KrF* laser source (λ = 248 nm, τ = 25 ns) was employed at fluences of 7 and 0.7J/cm(2) for HA and FN transfer, respectively. Films approximately 1500 and 450 nm thick were obtained for HA and FN, respectively. A new cryogenic temperature-programmed desorption mass spectrometry analysis method was employed to accurately measure the quantity of immobilized protein. We determined that less than 7 μg FN per cm(2) HA surface is adequate to improve adhesion, spreading, and differentiation of osteoprogenitor cells. We believe that the proposed fabrication method opens the door to combining and immobilizing two or more inorganic and organic materials on a solid substrate in a well-defined manner. The flexibility of this method enables the synthesis of new hybrid materials by simply tailoring the irradiation conditions according to the thermo-physical properties of the starting materials. PMID:25485841

  19. Corrosion protection by sonoelectrodeposited organic films on zinc coated steel.

    PubMed

    Et Taouil, Abdeslam; Mahmoud, Mahmoud Mourad; Lallemand, Fabrice; Lallemand, Séverine; Gigandet, Marie-Pierre; Hihn, Jean-Yves

    2012-11-01

    A variety of coatings based on electrosynthesized polypyrrole were deposited on zinc coated steel in presence or absence of ultrasound, and studied in terms of corrosion protection. Cr III and Cr VI commercial passivation were used as references. Depth profiling showed a homogeneous deposit for Cr III, while SEM imaging revealed good surface homogeneity for Cr VI layers. These chromium-based passivations ensured good protection against corrosion. Polypyrrole (PPy) was also electrochemically deposited on zinc coated steel with and without high frequency ultrasound irradiation in aqueous sodium tartrate-molybdate solution. Such PPy coatings act as a physical barrier against corrosive species. PPy electrosynthesized in silent conditions exhibits similar properties to Cr VI passivation with respect to corrosion protection. Ultrasound leads to more compact and more homogeneous surface structures for PPy, as well as to more homogeneous distribution of doping molybdate anions within the film. Far better corrosion protection is exhibited for such sonicated films. PMID:22516111

  20. Configurational effects of collagen/ALP coatings on enzyme immobilization and surface mineralization

    NASA Astrophysics Data System (ADS)

    Bosco, R.; Leeuwenburgh, S. C. G.; Jansen, J. A.; van den Beucken, J. J. J. P.

    2014-08-01

    The ultimate goal for surface modifications in bone implants is to achieve biologically active surface able to control and trigger specific tissue response. In this study was evaluated the effects of organic compound, derived from extracellular matrix, involved in tissue mineralization. Alkaline phosphatase (ALP) plays a fundamental role in bone mineralization concurrently with collagen, the main organic components of bones. Electrospray deposition (ESD) was used to coat titanium disks with ALP and collagen at room temperature. To verify the synergistic role of ALP and collagen different conformations of coatings (mixed and layered) were obtained and their mineralization capacity was tested in vitro. The mineralization tests indicated the fundamental role of collagen to increase ALP coating retention. Analyses indicated that the coating conformation has a role; in fact the mixed group showed improved ALP retention, enzymatic activity and unique mineralized surface morphology. ESD demonstrated to be a successful method to deposit organic molecules preserving their properties as indicated by the in vitro results. These findings proved the synergistic effect of ALP and collagen in inducing mineralization offering an intriguing coating constituent for medical device that aim to trigger surface mineralization such as bone implants.

  1. Preservation of York Minster historic limestone by hydrophobic surface coatings.

    PubMed

    Walker, Rachel A; Wilson, Karen; Lee, Adam F; Woodford, Julia; Grassian, Vicki H; Baltrusaitis, Jonas; Rubasinghege, Gayan; Cibin, Giannantonio; Dent, Andrew

    2012-01-01

    Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO(2) emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from 'breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO(2)/H(2)O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation. PMID:23198088

  2. Preservation of York Minster historic limestone by hydrophobic surface coatings

    NASA Astrophysics Data System (ADS)

    Walker, Rachel A.; Wilson, Karen; Lee, Adam F.; Woodford, Julia; Grassian, Vicki H.; Baltrusaitis, Jonas; Rubasinghege, Gayan; Cibin, Giannantonio; Dent, Andrew

    2012-11-01

    Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO2 emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from `breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO2/H2O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation.

  3. Preservation of York Minster historic limestone by hydrophobic surface coatings

    PubMed Central

    Walker, Rachel A.; Wilson, Karen; Lee, Adam F.; Woodford, Julia; Grassian, Vicki H.; Baltrusaitis, Jonas; Rubasinghege, Gayan; Cibin, Giannantonio; Dent, Andrew

    2012-01-01

    Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO2 emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from ‘breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO2/H2O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation. PMID:23198088

  4. Cd adsorption properties of components in different freshwater surface coatings: the important role of ferromanganese oxides.

    PubMed

    Dong, Deming; Hua, Xiuyi; Li, Yu; Zhang, Jingjing; Yan, Dongxu

    2003-09-15

    Surface coatings developed in different natural waters were used to study the role of the composition of surface coatings in controlling Cd adsorption in aquatic environments. To investigate the adsorption property of each component, the method of extraction techniques followed by Cd adsorption and statistical analysis were employed. Hydroxylamine hydrochloride was used to remove Mn oxides selectively, sodium dithionite was used to remove Mn and Fe oxides, and oxalic acid was used to remove most metal oxides and part of the organic material. Adsorption of Cd to surface coatings was measured before and after extraction under controlled laboratory conditions. The observed Cd adsorptions to unextracted and extracted surface coatings were analyzed using nonlinear least-squares fitting to estimate the adsorption property of each surface coating constituent. In different waters, the relative contribution to Cd adsorption of each component was different, but in all the waters studied, ferromanganese oxides contributed most with lesser roles indicated for organic phase and Al oxides. The Cd adsorption ability of manganese oxides was significantly higher than that of the other components. PMID:14524442

  5. Extended surface parallel coating inspection method

    DOEpatents

    Naulleau, Patrick P.

    2006-03-21

    Techniques for rapidly characterizing reflective surfaces and especially multi-layer EUV reflective surfaces of optical components involve illuminating the entire reflective surface instantaneously and detecting the image far field. The technique provides a mapping of points on the reflective surface to corresponding points on a detector, e.g., CCD. This obviates the need to scan a probe over the entire surface of the optical component. The reflective surface can be flat, convex, or concave.

  6. Role of surface coating on cathode materials for lithium-ion batteries.

    SciTech Connect

    Chen, Z.; Qin, Y.; Amine, K.; Sun, Y.-K.

    2010-01-01

    Surface coating of cathode materials has been widely investigated to enhance the life and rate capability of lithium-ion batteries. The surface coating discussed here was divided into three different configurations which are rough coating, core shell structure coating and ultra thin film coating. The mechanism of surface coating in achieving improved cathode performance and strategies to carry out this surface modification is discussed. An outlook on atomic layer deposition for lithium ion battery is also presented.

  7. Investigation of the serpentine coating on the steel surface

    NASA Astrophysics Data System (ADS)

    Kovalevskaya, Zh. G.; Khimich, M. A.; Veselov, S. V.; Belavskaya, O. A.; Tolmachev, A. I.; Bataev, V. A.

    2015-10-01

    The structure and phase composition of geomodifiers coating obtained on the surface of steel balls are examined using optical metallography, SEM and XRD. Coating has been formed for 672 hours by mixing of serpentine powder with steel balls in a ball mill. The coating has an adhesive bond to the substrate. The phase composition of the coating is different from the phase composition of the initial powder. The formation of the magnesium silicate is caused by the process of dehydration. Dehydration occurs due to local temperature fluctuations in the contact areas of the steel framework and serpentine in their interaction. It was determined that for formation of the coating of certain phase composition cumulative release of heat must meet the heating temperature higher than 550°C.

  8. Soot aggregate restructuring due to coatings of secondary organic aerosol derived from aromatic precursors.

    PubMed

    Schnitzler, Elijah G; Dutt, Ashneil; Charbonneau, André M; Olfert, Jason S; Jäger, Wolfgang

    2014-12-16

    Restructuring of monodisperse soot aggregates due to coatings of secondary organic aerosol (SOA) derived from hydroxyl radical-initiated oxidation of toluene, p-xylene, ethylbenzene, and benzene was investigated in a series of photo-oxidation (smog) chamber experiments. Soot aggregates were generated by combustion of ethylene using a McKenna burner, treated by denuding, size-selected by a differential mobility analyzer, and injected into a smog chamber, where they were exposed to low vapor pressure products of aromatic hydrocarbon oxidation, which formed SOA coatings. Aggregate restructuring began once a threshold coating mass was reached, and the degree of the subsequent restructuring increased with mass growth factor. Although significantly compacted, fully processed aggregates were not spherical, with a mass-mobility exponent of 2.78, so additional SOA was required to fill indentations between collapsed branches of the restructured aggregates before the dynamic shape factor of coated particles approached 1. Trends in diameter growth factor, effective density, and dynamic shape factor with increasing mass growth factor indicate distinct stages in soot aggregate processing by SOA coatings. The final degree and coating mass dependence of soot restructuring were found to be the same for SOA coatings from all four aromatic precursors, indicating that the surface tensions of the SOA coatings are similar. PMID:25390075

  9. Surface-plasmon-enhanced microcavity organic light-emitting diodes.

    PubMed

    Zhang, Hongmei; Chen, Shufen; Zhao, Dewei

    2014-12-15

    Efficiency enhancement of organic light-emitting diodes (OLEDs) can be obtained by the combination of microcavity effect and Au nanoparticles based surface plasmons. Au nanoparticles are thermally deposited on distributed Bragg reflector (DBR)-coated glass substrate, leading to realization of microcavity effect and localized surface plasmon effect. Our results show the current efficiency of OLEDs with DBR/Au nanoparticles as anode is increased by 72% compared to that with ITO as anode. PMID:25607492

  10. Plasma assisted surface coating/modification processes - An emerging technology

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1987-01-01

    A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation. These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

  11. Plasma assisted surface coating/modification processes: An emerging technology

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1986-01-01

    A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation). These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

  12. Surface-Functionalization of Nanostructured Cellulose Aerogels by Solid State Eumelanin Coating.

    PubMed

    Panzella, Lucia; Melone, Lucio; Pezzella, Alessandro; Rossi, Bianca; Pastori, Nadia; Perfetti, Marco; D'Errico, Gerardino; Punta, Carlo; d'Ischia, Marco

    2016-02-01

    Bioinspired aerogel functionalization by surface modification and coating is in high demand for biomedical and technological applications. In this paper, we report an expedient three-step entry to all-natural surface-functionalized nanostructured aerogels based on (a) TEMPO/NaClO promoted synthesis of cellulose nanofibers (TOCNF); (b) freeze-drying for aerogel preparation; and (c) surface coating with a eumelanin thin film by ammonia-induced solid state polymerization (AISSP) of 5,6-dihydroxyindole (DHI) or 5,6-dihydroxyindole-2-carboxylic acid (DHICA) previously deposited from an organic solution. Scanning electron microscopy showed uniform deposition of the dark eumelanin coating on the template surface without affecting porosity, whereas solid state (13)C NMR and electron paramagnetic resonance (EPR) spectroscopy confirmed the eumelanin-type character of the coatings. DHI melanin coating was found to confer to TOCNF templates a potent antioxidant activity, as tested by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays as well as strong dye adsorption capacity, as tested on methylene blue. The unprecedented combination of nanostructured cellulose and eumelanin thin films disclosed herein implements an original all-natural multifunctional aerogel biomaterial realized via an innovative coating methodology. PMID:26734842

  13. Development of durable self-cleaning coatings using organic-inorganic hybrid sol-gel method

    NASA Astrophysics Data System (ADS)

    Kumar, Divya; Wu, Xinghua; Fu, Qitao; Ho, Jeffrey Weng Chye; Kanhere, Pushkar D.; Li, Lin; Chen, Zhong

    2015-07-01

    Self-cleaning coatings with excellent water-repellence and good mechanical properties are in high demand. However, producing such coatings with resistance to mechanical abrasion and environmental weathering remains a key challenge. Mechanically robust coatings based on tetraethylorthosilicate (TEOS) and glycidoxypropyltriethoxysilane (Glymo) have been prepared using a sol-gel method. Emphasis is given to the addition of Glymo, an epoxy silane which creates an organic matrix that blends with the inorganic Sisbnd Osbnd Si matrix formed from the TEOS. The combination of the blended matrix produced coatings with good adhesion to substrates and improved mechanical properties. Fluoroalkylsilane (FAS) and silica fillers were introduced to increase the hydrophobicity of the coating. It was found that the water contact angle (CA) of these coatings increases from 115° to 164° upon decreasing filler size from 1-5 μm to 10-20 nm. The sliding angle (SA) for coatings with 15 wt.% loading of 10-20 nm silica is around 2°. UV weathering does not show significant effect on the properties of the coatings. Mechanical properties and performances including hardness, Young's modulus, coating adhesion and abrasion resistance were systematically analyzed. In the current work, a simple self-cleaning test, which measures the extent of dirt accumulation and subsequent removal by water spray, was performed. The coatings with 15 wt.% loading of 10-20 nm silica particles show the best self-cleaning performance both before and after mechanical abrasion. The developed coating process is simple and can be easily scaled-up for large surfaces that require self-cleaning function.

  14. Technology of Strengthening Steel Details by Surfacing Composite Coatings

    NASA Astrophysics Data System (ADS)

    Burov, V. G.; Bataev, A. A.; Rakhimyanov, Kh M.; Mul, D. O.

    2016-04-01

    The article considers the problem of forming wear resistant meal ceramic coatings on steel surfaces using the results of our own investigations and the analysis of achievements made in the country and abroad. Increasing the wear resistance of surface layers of steel details is achieved by surfacing composite coatings with carbides or borides of metals as disperse particles in the strengthening phase. The use of surfacing on wearing machine details and mechanisms has a history of more than 100 years. But still engineering investigations in this field are being conducted up to now. The use of heating sources which provide a high density of power allows ensuring temperature and time conditions of surfacing under which composites with peculiar service and functional properties are formed. High concentration of energy in the zone of melt, which is created from powder mixtures and the hardened surface layer, allows producing the transition zone between the main material and surfaced coating. Surfacing by the electron beam directed from vacuum to the atmosphere is of considerable technological advantages. They give the possibility of strengthening surface layers of large-sized details by surfacing powder mixtures without their preliminary compacting. A modified layer of the main metal with ceramic particles distributed in it is created as a result of heating surfaced powders and the detail surface layer by the electron beam. Technology of surfacing allows using powders of refractory metals and graphite in the composition of powder mixtures. They interact with one another and form the particles of the hardening phase of the composition coating. The chemical composition of the main and surfaced materials is considered to be the main factor which determines the character of metallurgical processes in local zones of melt as well as the structure and properties of surfaced composition.

  15. Failure analysis of blistered organic coatings on gray iron castings

    NASA Astrophysics Data System (ADS)

    Tianen, Matthew N.

    This study investigates the blistering failure of a two part coating consisting of talc-filled polyester resin and polyurethane primer on large gray iron castings. Surface metallography was performed and failed coating was characterized by scanning electron microscopy. Corrosion products were found inside of coating blisters. The proposed blistering mechanism is osmosis as a result of soluble species produced by the corrosion. It was believed that excessively thin primer layers resulted in a poor barrier to permeation of water, leading to blisters, and that a basecoat containing a corrosion inhibitor like zinc phosphate would reduce blistering. These hypotheses were tested with designed experiments using environmental testing in humidity and submersion environments. Thicker primer layers resulted in significant reductions in blistering and prolonged the time required before blister formation. A basecoat containing zinc phosphate was not found to be effective at reducing blistering in this coating system.

  16. Laminin coatings on implant surfaces promote osseointegration: Fact or fiction?

    PubMed

    Javed, Fawad; Al Amri, Mohammad D; Kellesarian, Sergio Varela; Al-Askar, Mansour; Al-Kheraif, Abdulaziz A; Romanos, Georgios E

    2016-08-01

    To our knowledge from indexed literature, the role of laminins in the expression of osteogenic biomarkers and osseointegration enhancement has not been systematically reviewed. The aim of the present systematic review was to assess the role of laminin coatings on implant surfaces in promoting osseointegration. To address the focused question, "Do laminin coatings on implant surfaces influence osseointegration?", indexed databases were searched from 1965 up to and including November 2015 using various combination of the following keywords: "Bone to implant contact"; "implant"; "laminins"; and "osseointegration". Letters to the Editor, case-reports/case-series, historic reviews, and commentaries were excluded. The pattern of the present systematic review was customized to primarily summarize the pertinent data. Nine studies were included. Six studies were prospective and were performed in animals and 5 studies were in vitro. Results from 8 studies showed that laminin coatings enhanced new bone formation around implants and/or bone-to-implant contact. One study showed that laminin coated implants surfaces did not improve osseointegration. On experimental grounds, laminin coatings seem to enhance osteogenic biomarkers expression and/or osseointegration; however, from a clinical perspective, further randomized control trials are needed to assess the role of laminin coatings in promoting osseointegration around dental implants. PMID:27164563

  17. Surface roughness reduction using spray-coated hydrogen silsesquioxane reflow

    NASA Astrophysics Data System (ADS)

    Cech, Jiri; Pranov, Henrik; Kofod, Guggi; Matschuk, Maria; Murthy, Swathi; Taboryski, Rafael

    2013-09-01

    Surface roughness or texture is the most visible property of any object, including injection molded plastic parts. Roughness of the injection molding (IM) tool cavity directly affects not only appearance and perception of quality, but often also the function of all manufactured plastic parts. So called “optically smooth” plastic surfaces is one example, where low roughness of a tool cavity is desirable. Such tool surfaces can be very expensive to fabricate using conventional means, such as abrasive diamond polishing or diamond turning. We present a novel process to coat machined metal parts with hydrogen silsesquioxane (HSQ) to reduce their surface roughness. Results from the testing of surfaces made from two starting roughnesses are presented; one polished with grit 2500 sandpaper, another with grit 11.000 diamond polishing paste. We characterize the two surfaces with AFM, SEM and optical profilometry before and after coating. We show that the HSQ coating is able to reduce peak-to-valley roughness more than 20 times on the sandpaper polished sample, from 2.44(±0.99) μm to 104(±22) nm and more than 10 times for the paste polished sample from 1.85(±0.63) μm to 162(±28) nm while roughness averages are reduced 10 and 3 times respectively. We completed more than 10,000 injection molding cycles without detectable degradation of the HSQ coating. This result opens new possibilities for molding of affordable plastic parts with perfect surface finish.

  18. Innovative fiber coating systems based on organic modified ceramics

    NASA Astrophysics Data System (ADS)

    Schuster, Kay; Kobelke, Jens; Rose, Klaus; Helbig, Manfred; Zoheidi, Mohammad; Heinze, Alexander

    2010-02-01

    We describe the application of inorganic organic hybrid materials (ORMOCERs) as optical fiber coatings for use in Fiber Bragg Grating sensors and high power transmission fibers. The materials are UV curable, enable a single layer thickness of about 50 μm and show high a high peak temperature stability >300 °C. Regarding the fiber protection the coatings have been investigated using tensile strength measurements before and after temperature load. Best coatings maintain the high tensile strength of 68 N (125 μm fiber) with a Weibull parameter of 182 after a temperature cycling up to 300 °C. For the first time a low refractive index ORMOCER will be presented showing a numerical aperture of 0.47 at a wavelength of 1000 nm on a pure silica fiber. This corresponds to a refractive index of 1.37. The fiber possesses a fiber loss of 18 dB/km at a wavelength of 1000 nm. The fibers have been coated using a gravity as well as pressure technology. The latter possesses extremely minimized die equipment and is therefore well applicable for small coating amounts. The so called dead volume within the coating die is about 1 ml. The overall dead volume is only influenced by the supply pipe and can be reduced down to 5 ml.

  19. Surface behaviour in deuterium permeation through erbium oxide coatings

    NASA Astrophysics Data System (ADS)

    Chikada, T.; Suzuki, A.; Adelhelm, C.; Terai, T.; Muroga, T.

    2011-06-01

    Suppression of tritium permeation through structural materials is essential in order to mitigate fuel loss and radioactivity concerns. Ceramic coatings have been investigated for over three decades as tritium permeation barriers (TPBs); however, a very limited number of investigations on the mechanism of hydrogen-isotope permeation through the coatings have been reported. In this study, deuterium permeation behaviour of erbium oxide coatings fabricated by filtered arc deposition on reduced activation ferritic/martensitic steels has been investigated. The samples coated on both sides of the substrates showed remarkably lower permeability than those coated on one side, and the maximum reduction efficiency indicated a factor of 105 compared with the substrate. The different permeation behaviour between the coatings facing the high and low deuterium pressure sides has been found by the crystal structure analysis and the evaluation of the energy barriers. It is suggested that the permeation processes on the front and back surfaces are independent, and the TPB efficiency of the samples coated on both sides can be expressed by a multiplication of that of each side.

  20. Transient thermography testing of unpainted thermal barrier coating surfaces

    NASA Astrophysics Data System (ADS)

    Ptaszek, Grzegorz; Cawley, Peter; Almond, Darryl; Pickering, Simon

    2013-01-01

    This paper has investigated the effects of uneven surface discolouration of a thermal barrier coating (TBC) and of its IR translucency on the thermal responses observed by using mid and long wavelength IR cameras. It has been shown that unpainted blades can be tested satisfactorily by using a more powerful flash heating system and a long wavelength IR camera. The problem of uneven surface emissivity can be overcome by applying 2nd derivative processing of the log-log surface cooling curves.

  1. Coating formulation and method for refinishing the surface of surface-damaged graphite articles

    DOEpatents

    Ardary, Zane L.; Benton, Samuel T.

    1988-01-01

    The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

  2. Coating formulation and method for refinishing the surface of surface-damaged graphite articles

    DOEpatents

    Ardary, Z.L.; Benton, S.T.

    1987-07-08

    The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

  3. Coating formulation and method for refinishing the surface of surface-damaged graphite articles

    DOEpatents

    Ardary, Z.L.; Benton, S.T.

    1988-11-22

    The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

  4. Methods for reducing volatile organic content in fabric waterproof coatings. Final report, May--November 1993

    SciTech Connect

    Keohan, F.L.; Lazaro, E.

    1994-03-01

    Fabrics for rainwear and outdoor equipment traditionally have been rendered waterproof by coating with solvent-borne rubber solutions, solvent-borne polyurethanes and vinyl plastisols. Regulatory pressure for environmental protection and worker safety has become a potent driving force in eliminating volatile organic solvents and toxic additives from commercial coating products. A variety of low-solvent coating technologies are being introduced to replace the traditional solvent-based products. These include high solids formulation, solventless UV and electron beam curing systems, powder coatings and supercritical, CO{sub 2}-reduced paints. The benefits and limitations of these coating technologies were compared with respect to their applicability to fabric waterproofing. In addition, a novel acrylated surfactant was synthesized and employed in the formulation of UV-curing waterborne coatings for textile waterproofing. The application methods and cure characteristics of the solvent-free formulations are described. Physical properties of cured coating films including tensile strength, percent elongation, water absorption, water drop contact angle, and adhesion to common fabrics were measured and compared to those obtained using a commercial waterborne waterproofing system. One formulation produced cured films having low water absorption, tenacious adhesion to polyester fabric and surface hydrophobicity properties approaching those of polyethylene.

  5. Ion beam textured and coated surfaces experiment (IBEX)

    NASA Technical Reports Server (NTRS)

    Mirtich, Michael J.; Stevens, Nicholas; Merrow, James

    1991-01-01

    The IBEX, with 36 samples of various materials, was placed aboard the LDEF. Twenty-seven of the samples had surfaces modified using ion beam technology, and nine were made up of commercially available materials. The materials are in some way useful in space power systems. The various types of materials tested included six categories: (1) ion beam structured surfaces suitable for solar thermal (concentrator) or space radiators; (2) ion beam sputtered conductive coatings for thermal and space charge control; (3) solar reflector surfaces; (4) flexible thin film coatings and solar array blanket material for protection of spacecraft polymers; (5) painted and/or state-of-the-art solar thermal materials; and (6) micrometeoroid sensitive detector. Data analysis presented include the optical properties of each surface before and after exposure to the space environment and the respective backup surfaces.

  6. Evaporative spray cooling of plain and microporous coated surfaces.

    SciTech Connect

    Kim, J. H.; You, S. M.; Choi, S. U.-S.; Energy Technology; Univ. of Texas at Arlington

    2004-07-01

    Experiments were performed on air and evaporative spray cooling of plain and microporous coated surfaces on flat and cylindrical heaters. Micron-size aluminum particles were used to build the microporous structures on the heated surfaces. To analyze the evaporative cooling, heat transfer curves were obtained in the form of the wall temperature difference versus heat flux. The heat transfer coefficients were also determined as a function of heat flux. Three water flow rates (1.25, 1.75 and 2.40 ml/min) were tested for the flat heater and one rate (3.0 ml/min) for the cylindrical heater, maintaining the air pressure of 7 psig (48 kPa) at the inlet of the nozzle. The effect of different particle sizes in the coating was also tested to optimize the microporous coating technique. Spraying water droplets on the microporous coating surface enhanced the heat removal due to the capillary pumping phenomenon through the microporous cavities connecting each other. The evaporative spray cooling increased the heat transfer coefficient by up to 400% relative to that of the uncoated surface cooled by dry air, and this enhancement was maintained at high heat fluxes by using microporous surfaces.

  7. Method of coating the interior surface of hollow objects with a diffusion coating

    DOEpatents

    Knowles, Shawn D.; Senor, David J.; Forbes, Steven V.; Johnson, Roger N.; Hollenberg, Glenn W.

    2005-03-15

    A method for forming a diffusion coating on the interior of surface of a hollow object wherein a filament, extending through a hollow object and adjacent to the interior surface of the object, is provided, with a coating material, in a vacuum. An electrical current is then applied to the filament to resistively heat the filament to a temperature sufficient to transfer the coating material from the filament to the interior surface of the object. The filament is electrically isolated from the object while the filament is being resistively heated. Preferably, the filament is provided as a tungsten filament or molybdenum filament. Preferably, the coating materials are selected from the group consisting of Ag, Al, As, Au, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Ge, Hg, In, K, Li, Mg, Mn, Na, Ni P, Pb, Pd, Pr, S, Sb, Sc, Se, Si, Sn, Sr, Te, Tl, Y, Yb, Zn, and combinations thereof. The invention additionally allows for the formation of nitrides, hydrides, or carbides of all the possible coating materials, where such compounds exist, by providing a partial pressure of nitrogen, hydrogen, hydrocarbons, or combination thereof, within the vacuum.

  8. Sol-gel network silica/modified montmorillonite clay hybrid nanocomposites for hydrophobic surface coatings.

    PubMed

    Meera, Kamal Mohamed Seeni; Sankar, Rajavelu Murali; Murali, Adhigan; Jaisankar, Sellamuthu N; Mandal, Asit Baran

    2012-02-01

    Sol-gel silica/nanoclay composites were prepared through sol-gel polymerization technique using tetraethylorthosilicate precursor and montmorillonite (MMT) clay in aqueous media. In this study, both montmorillonite-K(+) and organically modified MMT (OMMT) clays were used. The prepared composites were coated on glass substrate by making 1 wt% solution in ethyltrichlorosilane. The incorporation of nanoclay does not alter the intensity of characteristic Si-O-Si peak of silica network. Thermogravimetric studies show that increasing clay content increased the degradation temperature of the composites. Differential scanning calorimetry (DSC) results of organically modified MMT nanoclay incorporated composite show a shift in the melting behavior up to 38°C. From DSC thermograms, we observed that the ΔH value decreased with increasing clay loading. X-ray diffraction patterns prove the presence of nanoclay in the composite and increase in the concentration of organically modified nanoclay from 3 to 5 wt% increases the intensity of the peak at 2θ=8° corresponds to OMMT. Morphology of the control silica gel composite was greatly influenced by the incorporation of OMMT. The presence of nanoclay changed the surface of control silica gel composite into cleaved surface with brittle in nature. Contact angle measurements were done for the coatings to study their surface behavior. These hybrid coatings on glass substrate may have applications for hydrophobic coatings on leather substrate. PMID:22056084

  9. Smart Surfaces: New Coatings & Paints with Radiation Detection Functionality

    SciTech Connect

    Farmer, J; Choi, J

    2007-03-12

    Paints are being developed and tested that might ultimately be able to detect radiological agents in the environment by incorporating special pigments into an organic polymeric binder that can be applied as a paint or coatings. These paints detect radioactive sources and contaminants with inorganic or organic scintillation or thermo-luminescent pigments, which are selected based upon the radiation ({alpha}, {beta}, {gamma} or n) to be detected, and are shown in Figure 1.

  10. Impact of the organic coating on nanoparticles stability and reactivity

    NASA Astrophysics Data System (ADS)

    Gelabert, A.; Sivry, Y.; Ould Boualy, L.; Roselyne, F.; Juillot, F.; Menguy, N.; Benedetti, M. F.

    2010-12-01

    The strong increase in the use of engineered nanoparticles (NPs) during the last decade may ultimately result in their release in environmental settings, as predicted for different types of NPs by Gottshalk et al.. Most of these NPs incorporate functionalized coatings to gain industrial benefits, which in turn may play a critical rule for the whole NPs reactivity. Thus, along with stability studies focusing on the fate of NPs in natural systems, an accurate understanding of the coating impacts on the NPs behaviour and reactivity is highly required. This study aims to estimate the impact of three different coatings on the NPs dissolution rates in natural water (Seine river water), and their sorption properties onto a model mineral substrate. In this work, ZnO NPs have been coated, either with triethoxycaprylylsilane (hydrophobic), methacryloxypropyltrimethoxysilane (hydrophilic), or aminopropyltriethoxusilane (cationic). The dissolution rates were determined using two protocols: the Donnan Membrane Technique to measure the remaining free metal concentration in solution, and a 1 kDa ultrafiltration procedure to access both the free metal and small organic complexes part. For all three coating types, a fast dissolution step is reached in less than one day, followed by a slow precipitation of new mineral phases to finally reach a steady state. No major differences in the dissolution rates and profiles have been observed. Sorption studies on synthetic microsized goethite have been conducted at pH 7.5. The sorption ratio has been estimated as a function of initial NPs concentrations (from 10-7 M to 10-3 M), and follows a Langmuir shape for the hydrophobic and hydrophilic coatings at concentrations lower than 2.10-4 M. Interestingly, those two NPs exhibit high sorption capacities (10 times higher) compared to free Zn2+ sorption. On the other hand, at those concentrations, the cationic coating only induces a weak sorption without any defined trend. Moreover, for the

  11. Surface Coatings on Lunar Volcanic Glasses

    NASA Technical Reports Server (NTRS)

    Wentworth, Susan J.; McKay, D. S.; Thomas,-Keprta, K. L.; Clemett, S. J.

    2007-01-01

    We are undertaking a detailed study of surface deposits on lunar volcanic glass beads. These tiny deposits formed by vapor condensation during cooling of the gases that drove the fire fountain eruptions responsible for the formation of the beads. Volcanic glass beads are present in most lunar soil samples in the returned lunar collection. The mare-composition beads formed as a result of fire-fountaining approx.3.4-3.7 Ga ago, within the age range of large-scale mare volcanism. Some samples from the Apollo 15 and Apollo 17 landing sites are enriched in volcanic spherules. Three major types of volcanic glass bead have been identified: Apollo 15 green glass, Apollo 17 orange glass, and Apollo 17 "black" glass. The Apollo 15 green glass has a primitive composition with low Ti. The high-Ti compositions of the orange and black glasses are essentially identical to each other but the black glasses are opaque because of quench crystallization. A poorly understood feature common to the Apollo 15 and 17 volcanic glasses is the presence of small deposits of unusual materials on their exterior surfaces. For example, early studies indicated that the Apollo 17 orange glasses had surface enrichments of In, Cd, Zn, Ga, Ge, Au, and Na, and possible Pb- and Zn-sulfides, but it was not possible to characterize the surface features in detail. Technological advances now permit us to examine such features in detail. Preliminary FE-TEM/X-ray studies of ultramicrotome sections of Apollo 15 green glass indicate that the surface deposits are heterogeneous and layered, with an inner layer consisting of Fe with minor S and an outer layer of Fe and no S, and scattered Zn enrichments. Layering in surface deposits has not been identified previously; it will be key to defining the history of lunar fire fountaining.

  12. Combining hierarchical surface roughness with fluorinated surface chemistry to preserve superhydrophobicity after organic contamination

    NASA Astrophysics Data System (ADS)

    Wang, Chih-Feng; Hung, Shih-Wei; Kuo, Shiao-Wei; Chang, Chi-Jung

    2014-11-01

    Surfaces exhibiting superhydrophobicity are attracting commercial and academic attention because of their potential applications in, for example, self-cleaning utensils, microfluidic systems, and microelectronic devices. In this study, we prepared a fluorinated superhydrophobic surface displaying nanoscale roughness, a superhydrophobic surface possessing a micro- and nanoscale binary structure, and a fluorinated superhydrophobic surface possessing such a binary structure. We investigated the effects of the (i) hierarchy of the surface topography and (ii) the surface chemical composition of the superhydrophobic carbon nanotube/polybenzoxazine coatings on their ability to retain superhydrophobicity upon contamination with particles and organic matter, an important characteristic for maintaining non-wetting properties under outdoor conditions. We have found that the topographical microstructure and the surface chemical composition are both important factors for preservation of the non-wetting properties of such superhydrophobic surfaces upon contamination with organic matter.

  13. Surface coatings of bioactive glasses on high strength ceramic composites

    NASA Astrophysics Data System (ADS)

    Martorana, S.; Fedele, A.; Mazzocchi, M.; Bellosi, A.

    2009-04-01

    Dense and ultrafine alumina-zirconia composites (Al 2O 3-16 wt%ZrO 2 and ZrO 2-20 wt%Al 2O 3) are developed and characterized for load bearing prosthetic applications. The improvement of the ceramic/bone interface, namely of the ceramic bioactivity, is performed by a glass coating on the surface of the composites. A new composition is used to produce the glass powder, by melting at 1550 °C the mixture of oxide raw materials. The processing to obtain a homogeneous and adherent coating on the ceramic substrates is investigated: the optimal temperature for the glazing treatment is 1200 °C. The microstructure of the coating and of the ceramic/coating interface, the adhesion and some mechanical properties of the prepared glass and of the coating are analyzed. Besides, the in vitro bioactive responses, by incubation of osteoblast-like cells on the coated samples, are evaluated: positive results are confirmed after 24 h and 72 h.

  14. Regenerating Titanium Ventricular Assist Device Surfaces after Gold/ Palladium Coating for Scanning Electron Microscopy

    PubMed Central

    Achneck, Hardean E.; Serpe, Michael J; Jamiolkowski, Ryan; Eibest, Leslie M.; Craig, Stephen L.; Lawson, Jeffrey H.

    2014-01-01

    Titanium is one of the most commonly used materials for implantable devices in human s. Scanning electron microscopy (SEM) serves as an important tool for imaging titanium surfaces and analyzing cells and other organic matter adhering to titanium implants. However, high-vacuum SEM imaging of a non-conductive sample requires a conductive coating on the surface. A gold/ palladium coating is commonly used and to date no method has been described to ‘clean’ such gold/ palladium covered surfaces for repeated experiments without etching the titanium itself. This constitutes a major problem with titanium based implantable devices which are very expensive and thus in short supply. Our objective was to devise a protocol to regenerate titanium surfaces after SEM analysis. In a series of experiments, titanium samples from implantable cardiac assist devices were coated with fibronectin, seeded with cells and then coated with gold/palladium for SEM analysis. X-ray photoelectron spectroscopy spectra were obtained before and after five different cleaning protocols. Treatment with aqua regia (a 1:3 solution of concentrated nitric and hydrochloric acid), with or without ozonolysis, followed by sonication in soap solution and sonication in deionized water, allowed regenerating titanium surfaces to their original state. Atomic force microscopy confirmed that the established protocol did not alter the titanium microstructure. The protocol described herein is applicable to almost all titanium surfaces used in biomedical sciences and because of its short exposure time to aqua regia, will likely work for many titanium alloys as well. PMID:19642216

  15. Surface parameters modification by multilayer coatings deposition for biomedical applications

    NASA Astrophysics Data System (ADS)

    Zykova, A.; Safonov, V.; Virva, O.; Luk'yanchenko, V.; Walkowich, J.; Rogowska, R.; Yakovin, S.

    2008-05-01

    Studies are presented of the surface parameters of various multilayer coatings, namely, TiN, CrN, (Ti, Cr)N, TiN/TiC10N90, TiN/TiC20N80 deposited by means of Arc-PVD on stainless steel (1H18N9), as well as of the same coatings with an additional Al2O3 film deposited by reactive magnetron sputtering (RMS). The surface thickness, roughness and topography are estimated. Other parameters, such as the surface free energy (SFE) and fractional polarity are determined by means of the Wu and the Owens-Wendt-Rabel-Kaelble methods. Experiments are carried out on the in vitro cell/material interaction (in a fibroblasts culture) in order to determine the materials biomedical response. The results show some correlation between the surface properties and cell adhesion. The best biological response parameters (cell number, proliferation function, morphology) are obtained in the case of coatings with the highest values of the polar part component of the SFE and the fractional polarity, such as TiN, TiN/TiC10N90 and oxide coatings.

  16. Towards fully spray coated organic light emitting devices

    NASA Astrophysics Data System (ADS)

    Gilissen, Koen; Stryckers, Jeroen; Manca, Jean; Deferme, Wim

    2014-10-01

    Pi-conjugated polymer light emitting devices have the potential to be the next generation of solid state lighting. In order to achieve this goal, a low cost, efficient and large area production process is essential. Polymer based light emitting devices are generally deposited using techniques based on solution processing e.g.: spin coating, ink jet printing. These techniques are not well suited for cost-effective, high throughput, large area mass production of these organic devices. Ultrasonic spray deposition however, is a deposition technique that is fast, efficient and roll to roll compatible which can be easily scaled up for the production of large area polymer light emitting devices (PLEDs). This deposition technique has already successfully been employed to produce organic photovoltaic devices (OPV)1. Recently the electron blocking layer PEDOT:PSS2 and metal top contact3 have been successfully spray coated as part of the organic photovoltaic device stack. In this study, the effects of ultrasonic spray deposition of polymer light emitting devices are investigated. For the first time - to our knowledge -, spray coating of the active layer in PLED is demonstrated. Different solvents are tested to achieve the best possible spray-able dispersion. The active layer morphology is characterized and optimized to produce uniform films with optimal thickness. Furthermore these ultrasonic spray coated films are incorporated in the polymer light emitting device stack to investigate the device characteristics and efficiency. Our results show that after careful optimization of the active layer, ultrasonic spray coating is prime candidate as deposition technique for mass production of PLEDs.

  17. The Effect of Coating Thickness and Roughness of Nucleate Pool Boiling Heat Transfer on Nanoparticle Coated Surface

    NASA Astrophysics Data System (ADS)

    Das, Sudev; Bhaumik, Swapan

    2016-04-01

    The influence of coating thickness and surface roughness on pool boiling heat transfer is experimentally studied over a range of surface roughness values with varied coating thickness with water at atmospheric pressure. Test surfaces used in this experiment are namely, untreated surface (Ra = 0.0899 µm), polished surface (Ra = 0.0493 µm), TiO2 nanoparticle coated surface with a roughness (Ra) ranging from 0.0338 to 0.289 µm. The surfaces were characterized with respect to contact angle, surface roughness and coating thickness. The contact angle, surface roughness and coating thickness were measured by sessile drop method, optical surface profiler and instrument thickness monitor respectively. Heat fluxes observed ranged from 52.63 to 144.73 W/cm2. Different trends were observed in the Heat Transfer Coefficient (HTC) with respect to the surface roughness and coating thickness values on the same set of heat flux. The HTC was found to increase with increasing the roughness values for untreated and polish surface but nanoparticle coated surfaces displayed different trend in HTCs. The HTC was found to increase with increasing coating thickness with all wall superheat.

  18. Erosive separation of organic coatings from fibrous substrates.

    PubMed

    Weiss, M; Momber, A W

    2004-11-01

    The separation of organic coatings from fibrous substrates is a key problem in recycling processes. This problem applies to carpets, technical textiles and automotive interior components. This paper reports about results of laboratory studies involving the application of high-speed liquid jets to solve this problem. Results from high-speed video images are used to qualify the principal erosion process. It is shown that the coating material is first ground by the jet; the generated erosion debris is then pushed through the permeable fibrous fabric of the substrate. It is also found that threshold conditions exist for the coating grinding process and for the debris transportation. These threshold conditions depend on target composition and process parameters. A phenomenological separation model is introduced. The influence of key process parameters, namely jet velocity, exposure time, stand-off distance and impact angle, is also investigated. It is found that high-speed liquid jets are suitable tools for separating organic coatings completely and selectively from fibrous substrates. Recommendations on how to optimise the erosion process are derived from the results. PMID:15474739

  19. Switchable surface coatings for control over protein adsorption

    NASA Astrophysics Data System (ADS)

    Cole, Martin A.; Jasieniak, Marek; Voelcker, Nicolas H.; Thissen, Helmut; Horn, Roger; Griesser, Hans J.

    2007-12-01

    Control over biomolecule interactions at interfaces is becoming an increasingly important goal for a range of scientific fields and is being intensively studied in areas of biotechnological, biomedical and materials science. Improvement in the control over materials and biomolecules is particularly important to applications such as arrays, biosensors, tissue engineering, drug delivery and 'lab on a chip' devices. Further development of these devices is expected to be achieved with thin coatings of stimuli responsive materials that can have their chemical properties 'switched' or tuned to stimulate a certain biological response such as adsorption/desorption of proteins. Switchable coatings show great potential for the realisation of spatial and temporal immobilisation of cells and biomolecules such as DNA and proteins. This study focuses on protein adsorption onto coatings of the thermosensitive polymer poly(N-isopropylacrylamide) (pNIPAM) which can exhibit low and high protein adsorption properties based on its temperature dependent conformation. At temperatures above its lower critical solution temperature (LCST) pNIPAM polymer chains are collapsed and protein adsorbing whilst below the LCST they are hydrated and protein repellent. Coatings of pNIPAM on silicon wafers were prepared by free radical polymerisation in the presence of surface bound polymerisable groups. Surface analysis and protein adsorption was carried out using X-ray photoelectron spectroscopy, time of flight secondary ion mass spectrometry and contact angle measurements. This study is expected to aid the development of stimuli-responsive coatings for biochips and biodevices.

  20. Inorganic/organic hybrid nanocomposite coating applications: Formulation, characterization, and evaluation

    NASA Astrophysics Data System (ADS)

    Eyassu, Tsehaye

    Nanotechnology applications in coatings have shown significant growth in recent years. Systematic incorporation of nano-sized inorganic materials into polymer coating enhances optical, electrical, thermal and mechanical properties significantly. The present dissertation will focus on formulation, characterization and evaluation of inorganic/organic hybrid nanocomposite coatings for heat dissipation, corrosion inhibition and ultraviolet (UV) and near infrared (NIR) cut applications. In addition, the dissertation will cover synthesis, characterization and dispersion of functional inorganic fillers. In the first project, we investigated factors that can affect the "Molecular Fan" cooling performance and efficiency. The investigated factors and conditions include types of nanomaterials, size, loading amount, coating thickness, heat sink substrate, substrate surface modification, and power input. Using the optimal factors, MF coating was formulated and applied on commercial HDUs, and cooling efficiencies up to 22% and 23% were achieved using multi-walled carbon nanotube and graphene fillers. The result suggests that molecular fan action can reduce the size and mass of heat-sink module and thus offer a low cost of LED light unit. In the second project, we report the use of thin organic/inorganic hybrid coating as a protection for corrosion and as a thermal management to dissipate heat from galvanized steel. Here, we employed the in-situ phosphatization method for corrosion inhibition and "Molecular fan" technique to dissipate heat from galvanized steel panels and sheets. Salt fog tests reveal successful completion of 72 hours corrosion protection time frame for samples coated with as low as ~0.7microm thickness. Heat dissipation measurement shows 9% and 13% temperature cooling for GI and GL panels with the same coating thickness of ~0.7microm respectively. The effect of different factors, in-situ phosphatization reagent (ISPR), cross-linkers and nanomaterial on corrosion

  1. Washing-resistant surfactant coated surface is able to inhibit pathogenic bacteria adhesion

    NASA Astrophysics Data System (ADS)

    Treter, Janine; Bonatto, Fernando; Krug, Cristiano; Soares, Gabriel Vieira; Baumvol, Israel Jacob Rabin; Macedo, Alexandre José

    2014-06-01

    Surface-active substances, which are able to organize themselves spontaneously on surfaces, triggering changes in the nature of the solid-liquid interface, are likely to influence microorganism adhesion and biofilm formation. Therefore, this study aimed to evaluate chemical non-ionic surfactants activity against pathogenic microbial biofilms and to cover biomaterial surfaces in order to obtain an anti-infective surface. After testing 11 different surfactants, Pluronic F127 was selected for further studies due to its non-biocidal properties and capability to inhibit up to 90% of biofilm formation of Gram-positive pathogen and its clinical isolates. The coating technique using direct impregnation on the surface showed important antibiofilm formation characteristics, even after extensive washes. Surface roughness and bacterial surface polarity does not influence the adhesion of Staphylococcus epidermidis, however, the material coated surface became extremely hydrophilic. The phenotype of S. epidermidis does not seem to have been affected by the contact with surfactant, reinforcing the evidence that a physical phenomenon is responsible for the activity. This paper presents a simple method of surface coating employing a synthetic surfactant to prevent S. epidermidis biofilm formation.

  2. Method of making a coating of a microtextured surface

    DOEpatents

    Affinito, John D [Tucson, AZ; Graff, Gordon L [West Richland, WA; Martin, Peter M [Kennewick, WA; Gross, Mark E [Pasco, WA; Burrows, Paul E [Kennewick, WA; Sapochak, Linda S [Henderson, NV

    2004-11-02

    A method for conformally coating a microtextured surface. The method includes flash evaporating a polymer precursor forming an evaporate, passing the evaporate to a glow discharge electrode creating a glow discharge polymer precursor plasma from the evaporate, cryocondensing the glow discharge polymer precursor plasma on the microtextured surface and crosslinking the glow discharge polymer precursor plasma thereon, wherein the crosslinking resulting from radicals created in the glow discharge polymer precursor plasma.

  3. Surface Coating of Tungsten Carbide by Electric Exploding of Contact

    SciTech Connect

    Grigoryev, Evgeny G.

    2011-01-17

    Electric exploding of a tungsten carbide--cobalt material near-by high-speed steel surface forms on it a hardening coating. The essential structure properties of the formed coatings are determined by parameters of contact exploding electrode at the pulse current amplitude from above 106 A/cm2 and duration less than 10-4 s. The metallographic investigations of coating structures were done by microscope 'Neophot-24'. They have shown that the contact electric exploding caused the transfer of tungsten carbide and cobalt on the surface of high-speed steel. The breakdown of tungsten carbide--cobalt material took place during electrical exploding. The hardening layers of tungsten carbide and pure nanocrystalline tungsten have been formed upon the surface of high-speed steel as a result of electric exploding. Crystalline grains of tungsten have an almost spherical form and their characteristic size less than 400 nanometers. Micro hardness of the coating layers and high-speed steel structures was measured.

  4. Evaluation of UV-permeability and photo-oxidisability of organic ultraviolet radiation-absorbing coatings

    NASA Astrophysics Data System (ADS)

    Li, Neng; Chen, Yuhe; Bao, Yongjie; Zhang, Zeqian; Wu, Zaixing; Chen, Zhangmin

    2015-03-01

    Enhancing the durability of the coatings used on bamboo products is essential for increasing their use in outdoor environments. In this study, we investigated organic UV radiation-absorbing coatings for use on bamboo surfaces. The degree of resistance of the coatings, which contained 2-(2-hydroxy-3-tert-butyl-5-methyl-phenyl)-5-chlorinated benzotriazole (BTZ-1), to UV radiation degradation was determined through spectroscopic analysis. The critical BTZ-1 loading amount was determined by analysing the spectroscopic data. Fourier transform infrared spectroscopy was used to elucidate the relationship between the degree of photooxidation of the coatings and their BTZ-1 concentration. The experimental results showed that the coatings provided a high degree of shielding from UV radiation. The critical loading amount was determined to be 1.82 ± 0.05 g BTZ-1/m2. The coatings formed using the formulations that contained 3 and 5 wt% BTZ-1 exhibited the lowest degree of photooxidation after exposure to UV radiation.

  5. Organic matter induced mobilization of polymer-coated silver nanoparticles from water-saturated sand.

    PubMed

    Yang, Xinyao; Yin, Ziyi; Chen, Fangmin; Hu, Jingjing; Yang, Yuesuo

    2015-10-01

    Mobilization of polymer-coated silver nanoparticles (AgNPs) by anionic surfactant (sodium dodecylbenzenesulphonate: SDBS), amino acid derivative (N-acetylcysteine: NAC), and chelate (ethylenediaminetetraacetic acid: EDTA) in water-saturated sand medium was explored based on carefully designed column tests. Exposure experiments monitoring the size evolution of polyvinylpyrrolidone (PVP) coated AgNPs in organic solutions confirm the capacity of SDBS, NAC and EDTA to partly displace PVP. Single Pulse Column Experiment (SPCE) results show both the PVP polymer and the silver core controlled AgNP deposition while the effect of the PVP was dominant. Results of Co-injected Pulse Column Experiments (CPCEs) where AgNP and SDBS or NAC were co-injected into the column following a very short mixing (<1 s) disprove our hypothesis that coating-alternation by particle associated organic would mobilize irreversibly deposited particles from the uncoated sand, while surface charge modification by adsorbed NAC was identified as a potential mobilizing mechanism for AgNP from the iron-oxide-coated sand. Triple Pulse Column Experiment (TPCE) results confirm that such a charging effect of the adsorbed organic molecules may enable SDBS and NAC to mobilize AgNPs from the iron-oxide-coated sands. TPCE results with five distinct levels of SDBS indicate that concentration-stimulated change in the SDBS format from an individual to a micelle significantly increased the mobilizing efficiency and site blockage of SDBS. Although being an electrolyte, EDTA did not mobilize AgNPs, as the case with SDBS or NAC, as it dissolved the iron oxides which in turn prevented EDTA adsorption on sand. The findings have implications for better understanding the behavior of polymer-coated nanoparticles in organic-presented groundwater systems, i.e., detachment-associated uncertainty in exposure prediction of the nanomaterials. PMID:26011614

  6. Novel Active Surface Prepared by Embedded Functionalized Clays in an Acrylate Coating.

    PubMed

    Xia, Yining; Ghasemlou, Mehran; Rubino, Maria; Auras, Rafael; Baghdachi, Jamil

    2015-11-11

    The research on a self-decontaminating surface has received significant attention because of the growth of pathogenic microorganisms on surfaces. In this study, a novel and simple technique for producing an active surface with antimicrobial functionality is demonstrated. A tethering platform was developed by grafting the biocide ampicillin (Amp) to a nanoclay and dispersing the nanoclay in a UV-curable acrylate coating applied on polypropylene films as the substrate. A coupling agent, [3-(glycidyloxy)propyl]trimethoxysilane, was used as a linker between the nanoclay and Amp. The Amp-functionalized clay was further modified with an organic surfactant to improve the compatibility with the coating. Several characterization assays, such as Fourier infrared transform analysis, thermogravimetric analysis, and X-ray diffraction, were conducted to confirm the presence of Amp in the nanoclay. Transmission electron microscopy images revealed that the clay particles were well dispersed in the coating and had a partial exfoliated morphology. The active coating surface was effective in inhibiting the growth of Gram-positive Listeria monocytogenes and Gram-negative Salmonella Typhimurium via contact. These findings suggest the potential for the development of active surfaces with the implementation of nanotechnology to achieve diverse functionalities. PMID:26488557

  7. Regenerating titanium ventricular assist device surfaces after gold/palladium coating for scanning electron microscopy.

    PubMed

    Achneck, Hardean E; Serpe, Michael J; Jamiolkowski, Ryan M; Eibest, Leslie M; Craig, Stephen L; Lawson, Jeffrey H

    2010-01-01

    Titanium is one of the most commonly used materials for implantable devices in humans. Scanning electron microscopy (SEM) serves as an important tool for imaging titanium surfaces and analyzing cells and other organic matter adhering to titanium implants. However, high-vacuum SEM imaging of a nonconductive sample requires a conductive coating on the surface. A gold/palladium coating is commonly used and to date no method has been described to "clean" such gold/palladium covered surfaces for repeated experiments without etching the titanium itself. This constitutes a major problem with titanium-based implantable devices which are very expensive and thus in short supply. Our objective was to devise a protocol to regenerate titaniumsurfaces after SEM analysis. In a series of experiments, titanium samples from implantable cardiac assist devices were coated with fibronectin, seeded with cells and then coated with gold/palladium for SEM analysis. X-ray photoelectron spectroscopy spectra were obtained before and after five different cleaning protocols. Treatment with aqua regia (a 1:3 solution of concentrated nitric and hydrochloric acid), with or without ozonolysis, followed by sonication in soap solution and sonication in deionized water, allowed regenerating titanium surfaces to their original state. Atomic force microscopy confirmed that the established protocol did not alter the titanium microstructure. The protocol described herein is applicable to almost all titanium surfaces used in biomedical sciences and because of its short exposure time to aqua regia, will likely work for many titanium alloys as well. PMID:19642216

  8. Activation studies of NEG coatings by surface techniques

    SciTech Connect

    Sharma, R. K.; Jagannath,; Bhushan, K. G.; Gadkari, S. C.; Mukund, R.; Gupta, S. K.

    2013-02-05

    NEG (Non Evaporable Getters)materials in the form of ternary alloy coatings have many benefits compare to traditional bare surfaces such as Extreme high vacuum(XHV), lower secondary electron yield(SEY), low photon desorption cofficient. The extreme high vacuum (pressure > 10{sup -10} mbar) is very useful to the study of surfaces of the material, for high energy particle accelerators(LHC, Photon Factories), synchrotrons (ESRF, Ellectra) etc. Low secondary electron yield leads to better beam life time. In LHC the pressure in the interaction region of the two beams is something of the order of 10{sup -12} mbar. In this paper preparation of the coatings and their characterization to get the Activation temperature by using the surface techniques XPS, SEM and SIMS has been shown.

  9. Laser produced coatings and surface modifications for medical implants

    NASA Astrophysics Data System (ADS)

    León, B.

    2010-11-01

    Lasers can be an effective tool for tailoring the surface of medical implants. Laser irradiation can modify the surface wettability, bioactivity and its capacity to absorb proteins. By using appropriate energies and wavelengths, also the topographical features at macro, micro and nano level can be shaped in order to adapt to cells, extracellular matrices and orientation of ligand molecules. Pulsed laser deposition can produce nanometer thick, dense and well adhering CaP coatings with extremely fine control of chemistry and crystallinity. No further thermal annealing is needed. In-vitro and in-vivo experiments with different cells and animals models have demonstrated similar or better osseointegration of laser deposited coatings compared to the commercial available plasma sprayed ones. Ultraviolet lasers can successfully chemically functionalize the surface of implants, and femtosecond laser can drill polymer plates or meshes for tissue engineering applications.

  10. FUNCTIONALIZED LATERAL SURFACE COATED LASERS FOR CHEM-BIO DETECTION

    SciTech Connect

    Goddard, L L; Bond, T C; Cole, G D; Behymer, E M

    2007-07-05

    We present a class of compact, monolithic, photonic sensors consisting of multiple section edge emitting lasers with functionalized lateral surface coatings for low level detection of chemical or biological agents. Specifically, we discuss 8 {micro}m x 250 {micro}m Pd-coated H{sub 2} sensors and configurations to reduce the minimum detection limit from 138ppm for passive sensors to 1ppm for active sensors. Compared with conventional optical H{sub 2} sensors that use fiber gratings, surface plasmon resonances, or surface reflectance, our sensors offer the advantages of smaller size, wider dynamic range, monolithic integration of laser source and detector, and 2-D scalability to arrays of sensors that are functionalized to detect different agents.

  11. Aircraft surface coatings study: Verification of selected materials

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Three liquid coatings and four films that might improve and/or maintain the smoothness of transport aircraft surfaces are considered. Laboratory tests were performed on the liquid coatings (elastomeric polyurethanes) exposed to synthetic type hydraulic fluid, with and without a protective topcoat. Results were analyzed of a 14-month flight service evaluation of coatings applied to leading edges of an airline 727. Two additional airline service evaluations were initiated. Labortory tests were conducted on the films, bonded to aluminum substrate with various adhesives, to determine the best film/adhesive combinations. A cost/benefits analysis was performed and recommendations made for future work toward the application of this technology to commercial transports.

  12. Surface Modifications with Laser Synthesized Mo Modified Coating

    NASA Astrophysics Data System (ADS)

    Sun, Lu; Chen, Hao; Liu, Bo

    2013-02-01

    Mg-Cu-Al was first used to improve the surface performance of TA15 titanium alloys by means of laser cladding technique. The synthesis of hard composite coating on TA15 titanium alloy by laser cladding of Mg-Cu-Al-B4C/Mo pre-placed powders was investigated by means of scanning electron microscope, energy dispersive spectrometer and high resolution transmission electron microscope. Experimental results indicated that such composite coating mainly consisted of TiB2, TiB, TiC, Ti3Al and AlCuMg. Compared with TA15 alloy substrate, an improvement of wear resistance was observed for this composite coating due to the actions of fine grain, amorphous and hard phase strengthening.

  13. Effective mineral coatings for hardening the surface of metallic materials

    NASA Astrophysics Data System (ADS)

    Kislov, S. V.; Kislov, V. G.; Skazochkin, A. V.; Bondarenko, G. G.; Tikhonov, A. N.

    2015-07-01

    The structural changes that occur in the surface and surface layers of steel 20Kh13 and titanium alloy PT-3V (Russian designation) samples after each stage of hardening due to a formed mineral surface layer are studied by optical microscopy, transmission electron microscopy, and scanning electron microscopy. Electric spark alloying, pressing, and ultrasonic processing are used to reach the effect of volume compression of the base metal and the mineral in the plastic deformation zone. As a result, applied mineral particles concentrate in preliminarily created microvoids in a thin surface layer. The surface layer thus modified acquires a high hardness and wear resistance. Durometry shows that the hardness of the processed sample surfaces increases more than twofold. Therefore, the developed technology of creating a mineral coating can be used to increase the tribological properties of the surfaces of the parts, units, and mechanisms of turbine, pump, and mining equipment, which undergo intense wear during operation.

  14. Optimizing an SEM-based 3D surface imaging technique for recording bond coat surface geometry in thermal barrier coatings

    NASA Astrophysics Data System (ADS)

    Shahbazmohamadi, Sina; Jordan, Eric H.

    2012-12-01

    Creation of three-dimensional representations of surfaces from images taken at two or more view angles is a well-established technique applied to optical images and is frequently used in combination with scanning electron microscopy (SEM). The present work describes specific steps taken to optimize and enhance the repeatability of three-dimensional surfaces reconstructed from SEM images. The presented steps result in an approximately tenfold improvement in the repeatability of the surface reconstruction compared to more standard techniques. The enhanced techniques presented can be used with any SEM friendly samples. In this work the modified technique was developed in order to accurately quantify surface geometry changes in metallic bond coats used with thermal barrier coatings (TBCs) to provide improved turbine hot part durability. Bond coat surfaces are quite rough, and accurate determination of surface geometry change (rumpling) requires excellent repeatability. Rumpling is an important contributor to TBC failure, and accurate quantification of rumpling is important to better understanding of the failure behavior of TBCs.

  15. Excitation of surface plasmons in Al-coated SNOM tips

    NASA Astrophysics Data System (ADS)

    Palm, Viktor; Rähn, Mihkel; Jäme, Joonas; Hizhnyakov, Vladimir

    2012-10-01

    The mesoscopic effect of spectral modulation occurring due to the interference of two photonic fiber modes filtered out by a metal-coated SNOM tip is used to observe the surface plasmon polariton (SPP) excitation in SNOM tips. In a spectrum of the broadband light transmitted by a SNOM tip a region of highly regular spectral modulation can be found, indicating the spectral interval in which only two photonic modes (apparently HE11 and TM01) are transmitted with significant and comparable amplitudes. The modulation period yields the value of optical path difference (OPD) for this pair of modes. Due to the multimode fiber's inherent modal dispersion, this OPD value depends linearly on the fiber tail length l. An additional contribution to OPD can be generated in a metal-coated SNOM tip due to a mode-dependent photon-plasmon coupling strength resulting in generation of SPPs with different propagation velocities. For an Al-coated 200 nm SNOM tip spectra of transmitted light have been registered for ten different l values. An extrapolation of the linear OPD (l) dependence to l=0 yields a significant residual OPD value, indicating according to our theoretical considerations a mode-selective SPP excitation in the metal-coated tip. The modal dispersion is shown to switch its sign in the SNOM tip. First results of analogous experiments with an Al-coated 150 nm SNOM tip confirm our conclusions.

  16. Improved oxidation resistance of organic/inorganic composite atomic layer deposition coated cellulose nanocrystal aerogels

    SciTech Connect

    Smith, Sean W.; Matthews, David J.; Conley, John F.; Buesch, Christian; Simonsen, John

    2014-07-01

    Cellulose nanocrystal (CNC) aerogels are coated with thin conformal layers of Al{sub 2}O{sub 3} using atomic layer deposition to form hybrid organic/inorganic nanocomposites. Electron probe microanalysis and scanning electron microscopy analysis indicated the Al{sub 2}O{sub 3} penetrated more than 1500 μm into the aerogel for extended precursor pulse and exposure/purge times. The measured profile of coated fiber radius versus depth from the aerogel surface agrees well with simulations of precursor penetration depth in modeled aerogel structures. Thermogravimetric analysis shows that Al{sub 2}O{sub 3} coated CNC aerogel nanocomposites do not show significant thermal degradation below 295 °C as compared with 175 °C for uncoated CNC aerogels, an improvement of over 100 °C.

  17. Surface Diagnostics in Tribology Technology and Advanced Coatings Development

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1999-01-01

    This paper discusses the methodologies used for surface property measurement of thin films and coatings, lubricants, and materials in the field of tribology. Surface diagnostic techniques include scanning electron microscopy, transmission electron microscopy, atomic force microscopy, stylus profilometry, x-ray diffraction, electron diffraction, Raman spectroscopy, Rutherford backscattering, elastic recoil spectroscopy, and tribology examination. Each diagnostic technique provides specific measurement results in its own unique way. In due course it should be possible to coordinate the different pieces of information provided by these diagnostic techniques into a coherent self-consistent description of the surface properties. Examples are given on the nature and character of thin diamond films.

  18. "Effective" negative surface tension: a property of coated nanoaerosols relevant to the atmosphere.

    PubMed

    Chakraborty, Purnendu; Zachariah, Michael R

    2007-06-28

    Atmospheric aerosols play a very important role in atmospheric processes and have a major influence on the global climate. In this paper, we report results of a molecular dynamics study on the unique properties of organic-coated water droplets. In particular, we find that, for particles preferring an inverted micelle structure, the lower chain-chain interaction, with increasing radial distance from the water-organic interface, results in a negative internal radial pressure profile for the organic layer. As a result, a coated particle behaves as though the surface tension is "negative" and implies that such a particle will inherently have an inverse Kelvin vapor pressure effect, resulting in increased water condensation. PMID:17539611

  19. Self-organization of hydrophobic soil and granular surfaces

    NASA Astrophysics Data System (ADS)

    McHale, Glen; Shirtcliffe, Neil J.; Newton, Michael I.; Pyatt, F. Brian; Doerr, Stefan H.

    2007-01-01

    Soil can become extremely water repellent following forest fires or oil spillages, thus preventing penetration of water and increasing runoff and soil erosion. Here the authors show that evaporation of a droplet from the surface of a hydrophobic granular material can be an active process, lifting, self-coating, and selectively concentrating small solid grains. Droplet evaporation leads to the formation of temporary liquid marbles and, as droplet volume reduces, particles of different wettabilities compete for water-air interfacial surface area. This can result in a sorting effect with self-organization of a mixed hydrophobic-hydrophilic aggregate into a hydrophobic shell surrounding a hydrophilic core.

  20. Polydimethylsiloxane Coating for a Palladium/MOF Composite: Highly Improved Catalytic Performance by Surface Hydrophobization.

    PubMed

    Huang, Gang; Yang, Qihao; Xu, Qiang; Yu, Shu-Hong; Jiang, Hai-Long

    2016-06-20

    Surface wettability of active sites plays a crucial role in the activity and selectivity of catalysts. This report describes modification of surface hydrophobicity of Pd/UiO-66, a composite comprising a metal-organic framework (MOF) and stabilized palladium nanoparticles (NPs), using a simple polydimethylsiloxane (PDMS) coating. The modified catalyst demonstrated significantly improved catalytic efficiency. The approach can be extended to various Pd nanoparticulate catalysts for enhanced activity in reactions involving hydrophobic reactants, as the hydrophobic surface facilitates the enrichment of hydrophobic substrates around the catalytic site. PDMS encapsulation of Pd NPs prevents aggregation of NPs and thus results in superior catalytic recyclability. Additionally, PDMS coating is applicable to a diverse range of catalysts, endowing them with additional selectivity in sieving reactants with different wettability. PMID:27144320

  1. A dry-surface coating method for visualization of separation

    NASA Technical Reports Server (NTRS)

    Sadeh, W. Z.; Brauer, H. J.; Durgin, J. R.

    1981-01-01

    A simple and reasonably accurate dry-surface coating method for the visualization of the separation line on a bluff body is described. This method is not restricted to any particular Reynolds-number range and it supplies a clear permanent record of good photographic quality. Examination of this technique in visualizing the separation angle on a circular cylinder indicated that it is accurate within about + or - 4 percent.

  2. 40 CFR 63.5743 - What standards must I meet for aluminum recreational boat surface coating operations?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., clear coats, and top coats combined. No limit applies when cleaning surfaces are receiving decals or... liter of total coating solids applied from aluminum primers, clear coats, and top coats combined. (3... primers, clear coats, and top coats combined. (b) You must comply with the work practice standard...

  3. Lunar and Planetary Science XXXV: Mars: Surface Coatings, Mineralogy, and Surface Properties

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "Mars: Surface Coatings, Mineralogy, and Surface Properties" contained the following reports:High-Silica Rock Coatings: TES Surface-Type 2 and Chemical Weathering on Mars; Old Desert Varnish-like Coatings and Young Breccias at the Mars Pathfinder Landing Site; Analyses of IR-Stealthy and Coated Surface Materials: A Comparison of LIBS and Reflectance Spectra and Their Application to Mars Surface Exploration; Contrasting Interpretations of TES Spectra of the 2003 Rover:Opportunity-Landing Site: Hematite Coatings and Gray Hematite; A New Hematite Formation Mechanism for Mars; Geomorphic and Diagenetic Analogs to Hematite Regions on Mars: Examples from Jurassic Sandstones of Southern Utah, USA; The Geologic Record of Early Mars: A Layered, Cratered, and "Valley-"ed: Volume; A Simple Approach to Estimating Surface Emissivity with THEMIS; A Large Scale Topographic Correction for THEMIS Data; Thermophysical Properties of Meridiani Planum, Mars; Thermophysical and Spectral Properties of Gusev, the MER-Spirit Landing Site on Mars; Determining Water Content of Geologic Materials Using Reflectance Spectroscopy; and Global Mapping of Martian Bound Water at 6.1 Microns Based on TES Data: Seasonal Hydration.

  4. Inhibition of Sulfide Mineral Oxidation by Surface Coating Agents: Batch

    NASA Astrophysics Data System (ADS)

    Choi, J.; Ji, M. K.; Yun, H. S.; Park, Y. T.; Gee, E. D.; Lee, W. R.; Jeon, B.-H.

    2012-04-01

    Mining activities and mineral industries have impacted on rapid oxidation of sulfide minerals such as pyrite (FeS2) which leads to Acid Mine Drainage (AMD) formation. Some of the abandoned mines discharge polluted water without proper environmental remediation treatments, largely because of financial constraints in treating AMD. Magnitude of the problem is considerable, especially in countries with a long history of mining. As metal sulfides become oxidized during mining activities, the aqueous environment becomes acid and rich in many metals, including iron, lead, mercury, arsenic and many others. The toxic heavy metals are responsible for the environmental deterioration of stream, groundwater and soils. Several strategies to remediate AMD contaminated sites have been proposed. Among the source inhibition and prevention technologies, microencapsulation (coating) has been considered as a promising technology. The encapsulation is based on inhibition of O2 diffusion by surface coating agent and is expected to control the oxidation of pyrite for a long time. Potential of several surface coating agents for preventing oxidation of metal sulfide minerals from both Young-Dong coal mine and Il-Gwang gold mine were examined by conducting batch experiments and field tests. Powdered pyrite as a standard sulfide mineral and rock samples from two mine outcrops were mixed with six coating agents (KH2PO4, MgO and KMnO4 as chemical agents, and apatite, cement and manganite as mineral agents) and incubated with oxidizing agents (H2O2 or NaClO). Batch experiments with Young-Dong coal mine samples showed least SO42- production in presence of KMnO4 (16% sulfate production compared to no surface coating agents) or cement (4%) within 8 days. In the case of Il-Gwang mine samples, least SO42- production was observed in presence of KH2PO4 (8%) or cement (2%) within 8 days. Field-scale pilot tests at Il-Gwang site also showed that addition of KH2PO4 decreased sulfate production from 200 to

  5. Combinatorial materials research applied to the development of new surface coatings: VIII: Overview of the high-throughput measurement systems developed for a marine coating workflow

    NASA Astrophysics Data System (ADS)

    Chisholm, Bret J.; Stafslien, Shane J.; Christianson, David A.; Gallagher-Lein, Christy; Daniels, Justin W.; Rafferty, Crystal; Wal, Lyndsi Vander; Webster, Dean C.

    2007-11-01

    A combinatorial workflow has been produced for the development of novel, environmental-friendly marine coatings. A particularly challenging aspect of the workflow development was the selection and development of high-throughput screening methods that allow for some degree of prediction of coating performance in the aquatic environment of interest. The high-throughput screening methods currently in place include measurements of surface energy, viscoelastic properties, pseudobarnacle adhesion, and a suite of biological assays based on various marine organisms. An experiment involving a series of fouling-release coatings was used to correlate high-throughput screening data to data obtained from ocean site immersion testing. The results of the experiment showed that both bacterial biofilm surface coverage and storage modulus at 30 °C showed a good correlation with barnacle adhesion strength and a fair correlation with fouling rating, but surface energy and pseudobarnacle adhesion did not correlate with the results from ocean site testing.

  6. 40 CFR 63.5743 - What standards must I meet for aluminum recreational boat surface coating operations?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... from aluminum primers, clear coats, and top coats combined. No limit applies when cleaning surfaces are... top coats combined. (3) You must limit emissions from the combined aluminum surface coatings and... applied from aluminum primers, clear coats, and top coats combined. (b) You must comply with the...

  7. UV-Triggered Surface-Initiated Polymerization from Colorless Green Tea Polyphenol-Coated Surfaces.

    PubMed

    Bai, Guoqiang; Ma, Shuanhong; Qie, Runtian; Liu, Zhiqing; Shi, Yulin; Li, Cuihua; Wang, Rongjie; Guo, Xuhong; Zhou, Feng; Jia, Xin

    2016-08-01

    A facile and versatile approach to constructing colorless surface coatings based on green tea polyphenols is reported, which can further act as a photoinitiating layer to initiate radical polymerization. These colorless green tea polyphenol coatings are capable of successfully photografting polymer brushes, and the resulting polymer brush patterns show spatial shape adjustability by masked UV irradiation. Both surface modifications and photografted polymer brushes do not alter the original color of the substrates. This method could be promising for the development of surface modifications. PMID:27272437

  8. Metal organic chemical vapor deposition of environmental barrier coatings for the inhibition of solid deposit formation from heated jet fuel

    NASA Astrophysics Data System (ADS)

    Mohan, Arun Ram

    Solid deposit formation from jet fuel compromises the fuel handling system of an aviation turbine engine and increases the maintenance downtime of an aircraft. The deposit formation process depends upon the composition of the fuel, the nature of metal surfaces that come in contact with the heated fuel and the operating conditions of the engine. The objective of the study is to investigate the effect of substrate surfaces on the amount and nature of solid deposits in the intermediate regime where both autoxidation and pyrolysis play an important role in deposit formation. A particular focus has been directed to examining the effectiveness of barrier coatings produced by metal organic chemical vapor deposition (MOCVD) on metal surfaces for inhibiting the solid deposit formation from jet fuel degradation. In the first part of the experimental study, a commercial Jet-A sample was stressed in a flow reactor on seven different metal surfaces: AISI316, AISI 321, AISI 304, AISI 347, Inconel 600, Inconel 718, Inconel 750X and FecrAlloy. Examination of deposits by thermal and microscopic analysis shows that the solid deposit formation is influenced by the interaction of organosulfur compounds and autoxidation products with the metal surfaces. The nature of metal sulfides was predicted by Fe-Ni-S ternary phase diagram. Thermal stressing on uncoated surfaces produced coke deposits with varying degree of structural order. They are hydrogen-rich and structurally disordered deposits, spherulitic deposits, small carbon particles with relatively ordered structures and large platelets of ordered carbon structures formed by metal catalysis. In the second part of the study, environmental barrier coatings were deposited on tube surfaces to inhibit solid deposit formation from the heated fuel. A new CVD system was configured by the proper choice of components for mass flow, pressure and temperature control in the reactor. A bubbler was designed to deliver the precursor into the reactor

  9. Surface Organization Influences Bistable Vision

    ERIC Educational Resources Information Center

    Graf, Erich W.; Adams, Wendy J.

    2008-01-01

    A priority for the visual system is to construct 3-dimensional surfaces from visual primitives. Information is combined across individual cues to form a robust representation of the external world. Here, it is shown that surface completion relying on multiple visual cues influences relative dominance during binocular rivalry. The shape of a…

  10. Plasma sprayed coatings as surface treatments of aluminum adherends

    SciTech Connect

    Davis, G.D.; Whisnant, P.L.; Groff, G.B.; Shaffer, D.K.

    1996-12-31

    Plasma sprayed coatings have been evaluated as surface treatments for aluminum substrates being prepared for adhesive bonding. Blends of an aluminum-silicon alloy and polyester give the best performance. To establish durability performance, wedge tests were done using four common epoxy adhesives without primers. In all cases, the 60%Al-Si/40%polyester coating gave results superior to those of FPL-etched specimens and, in some cases, performance equivalent to PAA specimens. This roughness provides excellent opportunity for mechanical interlocking or physical bonding and allows a complex interphase to be formed as the adhesive penetrates into the coating. Crack growth measurements and subsequent failure analysis using x-ray photoelectron spectroscopy (XPS) indicate that crack propagation occurs within this complex interphase. The results also show that the aluminum and polyester components are synergistic and blends of the two give better performance than either component by itself The aluminum gives strength to the coating while the polyester provides toughness and improves moisture resistance.

  11. Pulse electrodeposition of adherent nickel coatings onto anodized aluminium surfaces

    NASA Astrophysics Data System (ADS)

    Frantz, Cédric; Vichery, Charlotte; Zechner, Johannes; Frey, Damian; Bürki, Gerhard; Cebeci, Halil; Michler, Johann; Philippe, Laetitia

    2015-03-01

    Aluminium is one of the mostly used elements in the industry because of its abundance and low weight. However, the deposition of a metallic coating requires performing the so-called zincate pre-treatment in order to allow the formation of inter-metallic bonds and thereby achieving sufficient adherence. In this work, porous anodic aluminium oxide (AAO) is used as an anchoring intermediate layer for nickel coatings. AAO is grown anodically in sulfuric acid and nickel coatings are deposited by potentiostatic reverse pulse electrodeposition onto as-anodized aluminium surfaces. The electrodeposition of nickel is initiated onto the electrochemically thinned barrier layer of AAO and pursued until the complete covering of the oxide. The electrochemical behavior of Watts and sulfamate baths is investigated by cyclic voltammetry for different barrier layer thickness, allowing to validate the thinning conditions and to determine the appropriate deposition potential of nickel. GD-OES measurements show that low duty cycles are necessary to achieve high filling ratio of the AAO. SEM micrographs show that a smooth uniform coating is obtained when nickel is deposited in presence of additives.

  12. Protective coatings of metal surfaces by cold plasma treatment

    NASA Technical Reports Server (NTRS)

    Manory, R.; Grill, A.

    1985-01-01

    The cold plasma techniques for deposition of various types of protective coatings are reviewed. The main advantage of these techniques for deposition of ceramic films is the lower process temperature, which enables heat treating of the metal prior to deposition. In the field of surface hardening of steel, significant reduction of treatment time and energy consumption were obtained. A simple model for the plasma - surface reactions in a cold plasma system is presented, and the plasma deposition techniques are discussed in view of this model.

  13. Organic grain coatings in primitive interplanetary dust particles: Implications for grain sticking in the Solar Nebula

    NASA Astrophysics Data System (ADS)

    Flynn, George J.; Wirick, Sue; Keller, Lindsay P.

    2013-10-01

    The chondritic porous interplanetary dust particles (CP IDPs), fragments of asteroids and comets collected by NASA high-altitude research aircraft from the Earth's stratosphere, are recognized as the least altered samples of the original dust of the Solar Nebula available for laboratory examination. We performed high-resolution, ~25 nm/pixel, x-ray imaging and spectroscopy on ultramicrotome sections of CP IDPs, which are aggregates of >104 grains, and identified and characterized ~100 nm thick coatings of organic matter on the surfaces of the individual grains. We estimated the minimum tensile strength of this organic glue to be ~150 to 325 N/m2, comparable to the strength of the weakest cometary meteors, based on the observation that the individual grains of ~5 μm diameter aggregate CP IDPs are not ejected from the particle by electrostatic repulsion due to charging of these IDPs to 10 to 15 volts at 1 A.U. in space. Since organic coatings can increase the sticking coefficient over that of bare mineral grains, these organic grain coatings are likely to have been a significant aid in grain sticking in the Solar Nebula, allowing the first dust particles to aggregate over a much wider range of collision speeds than for bare mineral grains.

  14. Wear Analysis of Thermal Spray Coatings on 3D Surfaces

    NASA Astrophysics Data System (ADS)

    Tillmann, W.; Luo, W.; Selvadurai, U.

    2014-01-01

    Even though the application of thermal spray coatings on complex geometries gained a greater interest in the last decade, the effect of different geometrical features on the wear behavior is still ill-defined. In this study, the wear resistance of FTC-FeCSiMn coated 3D surfaces was investigated. The wear test was carried out by means of two innovative testing procedures. The first test is a Pin-on-Tubes test where the rotating motion is realized by a lathe chuck. The specimens in the second test were fixed on the table and a robot arm operated the pin. This wear test was applied on specimens with concave or convex surfaces. The residual stresses, which were determined by means of an incremental hole-drilling method, show a dependency on the substrate geometry. The obtained stresses were put in relation to the different radii. After the wear test, a 3D-profilometer determined the wear volume and the sections of the coatings were characterized by a scanning electron microscope. The results indicate that the wear resistance is strongly influenced by the geometry of the substrate.

  15. Surface engineering of the quality factor of metal coated microcantilevers

    SciTech Connect

    Ergincan, O.; Kooi, B. J.; Palasantzas, G.

    2014-12-14

    We performed noise measurements to obtain the quality factor (Q) and frequency shift of gold coated microcantilevers before and after surface modification using focused ion beam. As a result of our studies, it is demonstrated that surface engineering offers a promising method to control and increase the Q factor up to 50% for operation in vacuum. Surface modification could also lead to deviations from the known Q ∼ P{sup −1} behavior at low vacuum pressures P within the molecular regime. Finally, at higher pressures within the continuum regime, where Q is less sensitive to surface changes, a power scaling Q ∼ P{sup c} with c ≈ 0.3 was found instead of c = 0.5. The latter is explained via a semi-empirical formulation to account for continuum dissipation mechanisms at significant Reynolds numbers Re ∼ 1.

  16. Effect of Coating Surface Finishing on Fatigue Behavior of C450 Steel CAPVD Coated with (Ti,Cr)N

    NASA Astrophysics Data System (ADS)

    Poursaiedi, E.; Salarvand, A.

    2016-06-01

    The present study evaluated the effect of the surface quality of a custom 450 stainless steel substrate coated with a (Ti,Cr)N nanolayer by cathodic arc physical vapor deposition on fatigue performance in air and in a 3.5% NaCl solution. Scanning electron microscopy was used to locate crack origin sites and characterize the coating. X-ray diffraction was used to analyze the phase formation and measurement of residual stress in the coating. The results showed that the determined in plane residual stress is compressive, with amount of - 2.8 ± 0.4 GPa. Chemical mechanical polishing was used to decrease the coating surface roughness (R a from 0.35 to 0.07 µm). This significantly decreased the area having a high stress concentration and delayed the appearance of micro-cracks in the coating during fatigue testing. The results showed that when the material is tested under axial loading at a maximum alternating stress of 555 to 930 MPa, the fatigue strength of coated specimens with polished surfaces increased 10.6% in air and 26.7% in NaCl solution over the coated specimens with normal surfaces. Post-treatment of the coating increased the fatigue strength 3.5% in air and 10.1% in NaCl solution over the uncoated specimens and the weakness of CAPVD coating was eliminated in the field of fatigue.

  17. Identification of an organic coating on marine aerosol particles by TOF-SIMS

    NASA Astrophysics Data System (ADS)

    Tervahattu, Heikki; Juhanoja, Jyrki; Kupiainen, Kaarle

    2002-08-01

    Marine aerosol particles play an important role in atmospheric processes. It has been suggested that as marine aerosol particles form, they acquire a coating of organic surfactants. This theory has been supported only by indirect evidence. Recently, we gave new morphological indication of such organic coating without however providing molecular speciation. Here we have studied the surface of marine aerosol particles by time-of-flight secondary ion mass spectrometry (TOF-SIMS), which is very suitable for surface research due to its unique combination of surface sensitivity and the detailed molecular information obtained. Spectra from the outermost surface gave high intensity for palmitic acid and lower peaks for other fatty acids. According to TOF-SIMS images, palmitic acid was distributed on small particles, similar with the marine particles. Sputtering stripped palmitic acid and revealed the inner core of the sea-salt particles. Our results show that fatty acids are important ingredients of the outermost surface layer of the studied aerosol particles.

  18. Insoluble coatings for Stirling engine heat pipe condenser surfaces

    NASA Technical Reports Server (NTRS)

    Dussinger, Peter M.

    1993-01-01

    The work done by Thermacore, Inc., Lancaster, Pennsylvania, for the Phase 1, 1992 SBIR National Aeronautics and Space Administration Contract, 'Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces' is described. The work was performed between January 1992 and July 1992. Stirling heat engines are being developed for electrical power generation use on manned and unmanned earth orbital and planetary missions. Dish Stirling solar systems and nuclear reactor Stirling systems are two of the most promising applications of the Stirling engine electrical power generation technology. The sources of thermal energy used to drive the Stirling engine typically are non-uniform in temperature and heat flux. Liquid metal heat pipe receivers are used as thermal transformers and isothermalizers to deliver the thermal energy at a uniform high temperature to the heat input section of the Stirling engine. The use of a heat pipe receiver greatly enhances system efficiency and potential life span. One issue that is raised during the design phase of heat pipe receivers is the potential solubility corrosion of the Stirling engine heat input section by the liquid metal working fluid. This Phase 1 effort initiated a program to evaluate and demonstrate coatings, applied to nickel based Stirling engine heater head materials, that are practically 'insoluble' in sodium, potassium, and NaK. This program initiated a study of nickel aluminide as a coating and developed and demonstrated a heat pipe test vehicle that can be used to test candidate materials and coatings. Nickel 200 and nickel aluminide coated Nickel 200 were tested for 1000 hours at 800 C at a condensation heat flux of 25 W/sq cm. Subsequent analyses of the samples showed no visible sign of solubility corrosion of either coated or uncoated samples. The analysis technique, photomicrographs at 200X, has a resolution of better than 2.5 microns (.0001 in). The results indicate that the heat pipe environment is not directly

  19. Insoluble coatings for Stirling engine heat pipe condenser surfaces

    NASA Astrophysics Data System (ADS)

    Dussinger, Peter M.

    1993-09-01

    The work done by Thermacore, Inc., Lancaster, Pennsylvania, for the Phase 1, 1992 SBIR National Aeronautics and Space Administration Contract, 'Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces' is described. The work was performed between January 1992 and July 1992. Stirling heat engines are being developed for electrical power generation use on manned and unmanned earth orbital and planetary missions. Dish Stirling solar systems and nuclear reactor Stirling systems are two of the most promising applications of the Stirling engine electrical power generation technology. The sources of thermal energy used to drive the Stirling engine typically are non-uniform in temperature and heat flux. Liquid metal heat pipe receivers are used as thermal transformers and isothermalizers to deliver the thermal energy at a uniform high temperature to the heat input section of the Stirling engine. The use of a heat pipe receiver greatly enhances system efficiency and potential life span. One issue that is raised during the design phase of heat pipe receivers is the potential solubility corrosion of the Stirling engine heat input section by the liquid metal working fluid. This Phase 1 effort initiated a program to evaluate and demonstrate coatings, applied to nickel based Stirling engine heater head materials, that are practically 'insoluble' in sodium, potassium, and NaK. This program initiated a study of nickel aluminide as a coating and developed and demonstrated a heat pipe test vehicle that can be used to test candidate materials and coatings. Nickel 200 and nickel aluminide coated Nickel 200 were tested for 1000 hours at 800 C at a condensation heat flux of 25 W/sq cm. Subsequent analyses of the samples showed no visible sign of solubility corrosion of either coated or uncoated samples. The analysis technique, photomicrographs at 200X, has a resolution of better than 2.5 microns (.0001 in). The results indicate that the heat pipe environment is not directly

  20. Graphene-coated surface plasmon resonance interfaces for studying the interactions between bacteria and surfaces.

    PubMed

    Subramanian, Palaniappan; Barka-Bouaifel, Fatiha; Bouckaert, Julie; Yamakawa, Nao; Boukherroub, Rabah; Szunerits, Sabine

    2014-04-23

    A variety of physical and chemical parameters are of importance for adhesion of bacteria to surfaces. In the colonization of mammalian organisms for example, bacterial fimbriae and their adhesins not only seek particular glycan sequences exposed on diverse epithelial linings, they also enable the bacteria to overcome electrostatic repulsion exerted by their selected surfaces. In this work, we present a new technique based on simplified model systems for studying the adhesion strength of different Escherichia coli strains. For this purpose, gold-based surface plasmon resonance (SPR) interfaces were coated with thin films of reduced graphene oxide (rGO) through electrophoretic deposition. The rGO matrix was post-modified with polyethyleneimine (PEI), poly(sodium 4-styrenesulfonate) (PSS), mannose, and lactose through π-stacking and/or electrostatic interactions by simple immersion of the SPR interface into their respective aqueous solutions. The adhesion behaviors of one uropathogenic and two enterotoxigenic Escherichia coli clinical isolates, that each express structurally characterized fimbrial adhesins, were investigated. It was found that the UTI89 cystitis isolate that carries the mannose-binding FimH adhesin was most attracted to the PEI- and mannose-modified surfaces, whereas the att25 diarrhoeal strain with the N-acetylglucosamine-specific F17a-G adhesin disintegrated the lactose-modified rGO. The highly virulent 107/86 strain interacted strongly with the PSS-modified graphene oxide, in agreement with the polybasic surroundings of the ABH blood group-binding site of the FedF adhesin, and showed a linear SPR response in a concentration range between 1 × 10(2) and 1 × 10(9) cfu/mL. PMID:24433135

  1. Sorption Characteristics of Sorption Material Coated on Heat Transfer surface of a Heat Exchanger

    NASA Astrophysics Data System (ADS)

    Inaba, Hideo; Komatsu, Fujio; Horibe, Akihiko; Haruki, Naoto; Machida, Akito

    This paper describes sorption characteristics of organic sorbent coated on heat transfer surface of a plate-fin-tube heat exchanger. The organic sorbent is a bridged complex of soldium polyacrylate. This bridged complex containing the carboxyl group as water vapor adsorption site has a larger adsorption abilities as compared with silica gel. The experiments in which the moist air was passed into the heat exchanger coated with sorption material were conducted under various conditions of air flow rate and the temperature of brine that was the heat transfer fluid to cool the air flow in the dehumidifying process. It is found that the sorption rate of vapor is affected by the air flow rate and the brine temperature. Meanwhile, the attempt of clarifying the sorption mechanism is also conducted. Finally the average mass transfer coefficient of the organic sorbent was non-dimensionalized as a function of Reynolds number and non-dimensional temperature. In addition, it was observed that the factor which affects the sorption rate in the water vapor sorption process of the organic sorbent coated on the heat exchanger shifts from the “adsorption step” to the “sorption step”.

  2. Coating thickness affects surface stress measurement of brush electro-plating nickel coating using Rayleigh wave approach.

    PubMed

    Liu, Bin; Dong, Shiyun; Xu, Binshi; He, Peng

    2012-09-01

    A surface ultrasonic wave approach was presented for measuring surface stress of brush electro-plating nickel coating specimen, and the influence of coating thickness on surface stress measurement was discussed. In this research, two Rayleigh wave transducers with 5MHz frequency were employed to collect Rayleigh wave signals of coating specimen with different static tensile stresses and different coating thickness. The difference in time of flight between two Rayleigh wave signals was determined based on normalized cross correlation function. The influence of stress on propagation velocity of Rayleigh wave and the relationship between the difference in time of flight and tensile stress that corresponded to different coating thickness were discussed. Results indicate that inhomogeneous deformation of coating affects the relationship between the difference in time of flight and tensile stress, velocity of Rayleigh wave propagating in coating specimen increases with coating thickness increasing, and the variation rate reduces of difference in time of flight with tensile stress increasing as coating thickness increases. PMID:22534060

  3. Influence of surface roughness on water- and oil-repellent surfaces coated with nanoparticles

    NASA Astrophysics Data System (ADS)

    Hsieh, Chien-Te; Chen, Jin-Ming; Kuo, Rong-Rong; Lin, Ta-Sen; Wu, Chu-Fu

    2005-02-01

    Various rough surfaces coated with titanium oxide nanoparticles and perfluoroalkyl methacrylic copolymer were conducted to explore the influence of surface roughness on the performance of water- and oil-repellence. Surface characteristics determined from nitrogen physisorption at -196 °C showed that the surface area and pore volume increased significantly with the extent of nanoparticle ratio, indicating an increase of surface roughness. Due to the surface nano-coating, the maximum contact angles of water and ethylene glycol (EG) droplets increased up to 56 and 48%, respectively, e.g. from 105° to 164° for water droplets and from 96° to 144° for EG droplets. The excellent water- and oil-repellence of the prepared surfaces was ascribed to this increase of surface roughness and fluorinated-contained surface. Compared with Wenzel model, the Cassie model yielded a fairly good fit to the simulation of contact angle with surface roughness. However, a derivation of 3°-10° at higher roughness still existed. This phenomenon was very likely due to the surface heterogeneity with different pore size distributions of the fractal surfaces. In this case, it was unfavorable for super repellency from rough surface with larger mesopore fraction because of its capillary condensation, reflecting that micropore provided more air resistance against wettability.

  4. Effect of model dissolved organic matter coating on sorption of phenanthrene by TiO2 nanoparticles.

    PubMed

    Wang, Xilong; Ma, Enxing; Shen, Xiaofang; Guo, Xiaoying; Zhang, Meng; Zhang, Haiyun; Liu, Ye; Cai, Fei; Tao, Shu; Xing, Baoshan

    2014-11-01

    Dissolved organic matter (DOM) may alter the sorption of hydrophobic organic contaminants (HOC) to metal oxide nanoparticles (NPs), but the role of DOM and NP types is poorly understood. Here, phenanthrene sorption was quantified on four types of nano-TiO2 (three rutile, one anatase), and a bulk, raw TiO2 powder. Prior to the sorption experiments, these nanoparticles were coated using four different organic materials: Lignin (LIG), tannic acid (TAN), Congo red (CON), and capsorubin (CAP). Lignin, tannic acid, congo red and capsorubin coating substantially enhanced phenanthrene sorption to various TiO2 particles. After coating with a specific DOM, Kd values by the DOM-coated TiO2 particles on percent organic carbon content and surface area (SA) basis (Koc/SA) generally followed the order: TiO2 NPs with hydrophobic surfaces > bulk TiO2 particles > other TiO2 NPs. Different Koc/SA values of various DOM-TiO2 complexes resulted from distinct conformation of the coated DOM and aggregation. PMID:25089890

  5. Plasma printing: patterned surface functionalisation and coating at atmospheric pressure.

    PubMed

    Penache, C; Gessner, C; Betker, T; Bartels, V; Hollaender, A; Klages, C-P

    2004-08-01

    A new plasma-based micropatterning technique, here referred to as plasma printing, combines the well known advantages given by the nonequilibrium character of a dielectric barrier discharge (DBD) and its operation inside small gas volumes with dimension between tens and hundreds of micrometres. The discharge is run at atmospheric pressure and can be easily implemented for patterned surface treatment with applications in biotechnology and microtechnology. In this work the local modification of dielectric substrates, e.g. polymeric films, is addressed with respect to coating and chemical functionalisation, immobilisation of biomolecules and area-selective electroless plating. PMID:16475858

  6. Contaminated implant surfaces: an in vitro comparison of implant surface coating and treatment modalities for decontamination.

    PubMed

    Dennison, D K; Huerzeler, M B; Quinones, C; Caffesse, R G

    1994-10-01

    The relationship between implant surfaces and decontamination treatments was studied in vitro to determine which implant surfaces were most effectively decontaminated, and which treatment was most effective for treating a particular implant surface. The implants used in the study were press fit cylindrical titanium units with machined, plasma sprayed, and hydroxyapatite-coated surfaces. Radioactive endotoxin (125I-LPS) was prepared from Porphyromonas gingivalis (ATCC 33277). Implants were coated with 125I-LPS and treated by burnishing with a cotton pellet soaked in water, citric acid solution (CA), or 0.12% chlorhexidine (CHX); or treated with an air-powder abrasive (AIR). Radioactivity was determined after each of two treatment cycles. The results for each implant surface were analyzed using ANOVA to determine differences between treatments. The remaining 125I-LPS after two treatment cycles were: for machined implants AIR < CA, with AIR = water = CHX and water = CHX = CA; for plasma sprayed implants AIR < water = CHX = CA; for hydroxyapatite implants AIR = CA < water < CHX. In evaluating treatment modalities, it was found that machined implants were decontaminated more effectively than the other surfaces by all treatments; the exception was citric acid treatment which was equally effective on either machined or hydroxyapatite surfaces. These results indicate that machined implants (without surface coating) are most readily decontaminated by a variety of methods; this characteristic should be considered, since long-term success of implants may involve treating periimplantitis. Further, the results indicate that air abrasives are effective for decontaminating implant surface, with the exception that hydroxyapatite coated surfaces can be treated equally with air abrasives or citric acid. PMID:7823276

  7. Surface photovoltage characterization of organic photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Lee, Yun-Ju; Wang, Jian; Hsu, Julia W. P.

    2013-10-01

    Surface photovoltage response in bulk heterojunction organic solar cells is determined using a Kelvin probe with variable illumination intensity and wavelength. The effect of device architecture, carrier transport layers, donor:acceptor combinations, and device processing conditions are studied. We observe a positive (negative) surface photovoltage response, corresponding to efficient accumulation of electrons (holes) at the top electrode in conventional (inverted) devices. The linear relationship between surface photovoltage and log(intensity) and the agreement with open circuit voltage indicate that surface photovoltage magnitude quantifies the separation of photogenerated carriers in organic solar cells at open circuit condition.

  8. EVALUATION OF INNOVATIVE LOW-VOLATILE ORGANIC COMPOUND (VOC) INDUSTRIAL MAINTENANCE (IM) COATINGS

    EPA Science Inventory

    The paper discusses a field evaluation of the feasibility of using alternative low-volatile organic compound (VOC) coatings to replace higher-VOC coatings. he evaluation includes chemical, performance, and outdoor exposure testing. he feasibility of five alternative coatings for ...

  9. Analysis of metal surfaces coated with europium-doped titanium dioxide by laser induced breakdown spectroscopy.

    PubMed

    Głogocka, Daria; Noculak, Agnieszka; Pucińska, Joanna; Jopek, Wojciech; Podbielska, Halina; Langner, Marek; Przybyło, Magdalena

    2015-01-01

    The surface passivation with titanium sol-gel coatings is a frequently used technique to control the adsorption of selected biological macromolecules and to reduce the exposure of the bulk material to biological matter. Due to the increasing number of new coating-preparation methods and new gel compositions with various types of additives, the quality and homogeneity determination of the surface covering is a critical factor affecting performance of any implanted material. While coating thickness is easy to determine, the homogeneity of the surface distribution of coating materials requires more elaborate methodologies. In the paper, the laser induced breakdown spectroscopy (LIBS) based method, capable to quantitate the homogeneity and uniformity of the europium in titanium dioxide sol-gel coatings on stainless steel surfaces prepared with two different procedures: spin-coating and dip-coating, is presented. The emission intensity of titanium has been used to determine the coating thickness whereas the relative values of europium and titanium emission intensities provide data on the coating homogeneity. The obtained results show that the spin-coating technique provides better surface coverage with titanium dioxide. However, when the surface coating compositions were compared the dip-coating technique was more reliable. PMID:26687457

  10. Influence of viscoelastic property on laser-generated surface acoustic waves in coating-substrate systems

    SciTech Connect

    Sun Hongxiang; Zhang Shuyi; Xu Baiqiang

    2011-04-01

    Taking account of the viscoelasticity of materials, the pulsed laser generation of surface acoustic waves in coating-substrate systems has been investigated quantitatively by using the finite element method. The displacement spectra of the surface acoustic waves have been calculated in frequency domain for different coating-substrate systems, in which the viscoelastic properties of the coatings and substrates are considered separately. Meanwhile, the temporal displacement waveforms have been obtained by applying inverse fast Fourier transforms. The numerical results of the normal surface displacements are presented for different configurations: a single plate, a slow coating on a fast substrate, and a fast coating on a slow substrate. The influences of the viscoelastic properties of the coating and the substrate on the attenuation of the surface acoustic waves have been studied. In addition, the influence of the coating thickness on the attenuation of the surface acoustic waves has been also investigated in detail.

  11. Improvement of surface properties of SLM parts by atmospheric plasma spraying coating

    NASA Astrophysics Data System (ADS)

    Zhang, Baicheng; Zhu, Lin; Liao, Hanlin; Coddet, Christian

    2012-12-01

    Although selective laser melting (SLM) provides many advantages compared to conventional forming methods, limited surface quality is one of the major drawbacks restricting its application. As a remedy, the ceramic coating was deposited on the SLM parts surface in order to improve surface quality in this study. Furthermore, the combination of SLM and APS makes a great possibility to obtain special function material for special application. In this work, the bonding condition between ceramic coating and stainless steel parts were observed by optical microscope and SEM. The surface morphology and roughness were measured by a 3D-profilemeter. The microhardness and bonding strength of the ceramic coating were also measured. This paper presents two types of bonding mechanisms between ceramic coating and SLM parts with horizontal/vertical surface. It can be found that the bonding strength of the coating on the vertical surface was approximately 40 MPa, but the bonding strength of coating on the horizontal surface is relatively weaker.

  12. Estimating attachment of nano- and submicrometer-particles coated with organic macromolecules in porous media: development of an empirical model.

    PubMed

    Phenrat, Tanapon; Song, Jee Eun; Cisneros, Charlotte M; Schoenfelder, Daniel P; Tilton, Robert D; Lowry, Gregory V

    2010-06-15

    Assessing the environmental transport and fate of manufactured nanoparticles (NPs) and potential exposure risks requires models for predicting attachment of NPs coated with organic macromolecules in porous media. The objective of this study was to determine the properties of coated nanoparticles that control their attachment behavior. Deposition data for a variety of nanoparticles with different types of anionic organic coatings, including natural organic matter (NOM)-coated latex and hematite nanoparticles, and poly(styrenesulfonate)-, carboxymethylcellulose-, and polyaspartate-coated hematite and titanium dioxide nanoparticles (80 data points), were used to develop an empirical correlation between measurable NP properties and their sticking coefficient (alpha) under a variety of electrolyte conditions and flow velocities. Available semiempirical correlations used to predict the attachment efficiency of electrostatically stabilized (uncoated) NPs overestimate the attachment efficiency of nanoparticles coated with NOM or synthetic polyelectrolytes because the correlations neglect electrosteric repulsions and the decreased friction afforded by such coatings that can inhibit attachment to surfaces. Adding a dimensionless parameter (N(LEK)) representing steric repulsions and the decreased friction force afforded by adsorbed NOM or anionic polyelectrolytes in the correlation significantly improves the correlation. This establishes the importance of including the adsorbed NOM- or polyelectrolyte layer properties for estimating the attachment efficiency of NPs in the environment. The form of N(LEK) suggests that limiting unintended transport and exposure to NPs could be achieved by using coatings with the smallest adsorbed mass and polymer density, shortest extended layer thickness, and largest molecular weight that would still afford the desired functionality of the coating. PMID:20465214

  13. Potential of photon and particle beams for surface treatment of thin ceramic coatings

    NASA Astrophysics Data System (ADS)

    Celis, J. P.; Franck, M.; Roos, J. R.; Kreutz, E. W.; Gasser, A.; Wehner, M.; Wissenbach, K.; Pattyn, N.

    1992-01-01

    Laser irradiation and ion implantation have been investigated in order to modify in a two-step process the characteristics of TiN ceramic coatings obtained by physical vapour deposition (PVD) on steel surfaces. Depending on the beam properties and processing variables used, material modifications can be induced either in the coating itself, at the coating/substrate interface, or in the underlying substrate material. Laser irradiation and ion implantation offer possibilities of tailoring the functional surface properties of coated steels with respect to friction and wear resistance by the modification of surface roughness, by the alloying of ceramic coatings with either metallic or metalloid elements, and by inducing substrate hardening.

  14. Organic chemistry on Titan: Surface interactions

    NASA Technical Reports Server (NTRS)

    Thompson, W. Reid; Sagan, Carl

    1992-01-01

    The interaction of Titan's organic sediments with the surface (solubility in nonpolar fluids) is discussed. How Titan's sediments can be exposed to an aqueous medium for short, but perhaps significant, periods of time is also discussed. Interactions with hydrocarbons and with volcanic magmas are considered. The alteration of Titan's organic sediments over geologic time by the impacts of meteorites and comets is discussed.

  15. Ozone Oxidation of Self-Assembled Monolayers on SiOx-Coated Zinc Selenide Surfaces

    NASA Astrophysics Data System (ADS)

    McIntire, T. M.; Ryder, O. S.; Finlayson-Pitts, B. J.

    2008-12-01

    Airborne particles are important for visibility, human health, climate, and atmospheric reactions. Atmospheric particles contain a significant fraction of organics and such compounds present on airborne particles are susceptible to oxidation by atmospheric oxidants, such as OH, ozone, halogen atoms, and nitrogen trioxide. Oxidized organics associated with airborne particles are thought to be polar, hygroscopic species with enhanced cloud-nucleating properties. Oxide layers on silicon, or SiO2-coated substrates, act as models of environmentally relevant surfaces such as dust particles upon which organics adsorb. We have shown previously that ozone oxidation of unsaturated self-assembled monolayers (SAMs) on silicon attenuated total reflectance (ATR) crystals leads to the formation of carbonyl groups and micron-sized, hydrophobic organic aggregates surrounded by carbon depleted substrate that do not have increased water uptake as previously assumed. Reported here are further ATR-FTIR studies of the oxidation of alkene SAMs on ZnSe and SiO2-coated ZnSe. These substrates have the advantage that they transmit below 1500 cm-1, allowing detection of additional product species. These experiments show that the loss of C=C and formation of carbonyl groups is also accompanied by formation of a peak at 1110 cm-1, attributed to the secondary ozonide. Details concerning the products and mechanism of ozonolysis of alkene SAMs on surfaces based on these new data are presented and the implications for the oxidation of alkenes on airborne dust particles are discussed.

  16. A conductive surface coating for Si-CNT radiation detectors

    NASA Astrophysics Data System (ADS)

    Valentini, Antonio; Valentini, Marco; Ditaranto, Nicoletta; Melisi, Domenico; Aramo, Carla; Ambrosio, Antonio; Casamassima, Giuseppe; Cilmo, Marco; Fiandrini, Emanuele; Grossi, Valentina; Guarino, Fausto; Angela Nitti, Maria; Passacantando, Maurizio; Santucci, Sandro; Ambrosio, Michelangelo

    2015-08-01

    Silicon-Carbon Nanotube radiation detectors need an electrically conductive coating layer to avoid the nanotube detachment from the silicon substrate and uniformly transmit the electric field to the entire nanotube active surface. Coating material must be transparent to the radiation of interest, and must provide the drain voltage necessary to collect charges generated by incident photons. For this purpose various materials have been tested and proposed in photodetector and photoconverter applications. In this article interface properties and electrical contact behavior of Indium Tin Oxide films on Carbon Nanotubes have been analyzed. Ion Beam Sputtering has been used to grow the transparent conductive layer on the nanotubes. The films were deposited at room temperature with Oxygen/Argon mixture into the sputtering beam, at fixed current and for different beam energies. Optical and electrical analyses have been performed on films. Surface chemical analysis and in depth profiling results obtained by X-ray Photoelectron Spectroscopy of the Indium Tin Oxide layer on nanotubes have been used to obtain the interface composition. Results have been applied in photodetectors realization based on multi wall Carbon Nanotubes on silicon.

  17. Boiling on horizontal surfaces coated with porous metal wicks

    SciTech Connect

    Abou-Zyan, H.Z.; Plumb, O.A.

    1997-07-01

    Boiling experiments intended to simulate heat pipe operating conditions were conducted on a copper surface covered with copper foametal and nickel fiber wicks 3.175 and 4.760 mm thick. The experiments were conducted on a horizontal surface open to the atmosphere with water as the working fluid. The experimental surface was operated like a heat pipe with distilled water supplied upstream of the heated section and transported by capillary action across a section which was adiabatic to the heated section where boiling took place. At low excess temperature, less than 10 to 20 C, the heat flux from the porous coated surfaces is comparable to or greater than that predicted for a smooth surface using the Rohsenow correlation. At higher excess temperatures corresponding to heat fluxes between 10{sup 5} and 10{sup 6} W/m{sup 2} the increase in heat flux with excess temperature is much less than that predicted by the Rohsenow correlation. When the wicks were vented by cutting slots covering 10 to 20% of the total surface area the heat flux increased, in some cases by a factor of three, for a given excess temperature. The heat flux at which the slope of the boiling curve decreased also increased for the vented surfaces. This is attributed to the provision of a low resistance path for the steam to escape providing a surface that is more highly wetted. A mathematical model for the transport with boiling in the porous wick is developed in an attempt to gain further understanding of the processes involved. The model predicts dryout conditions that are in reasonable agreement with experimental observations. However, the model predicts decreasing vapor pressure, and hence temperature, adjacent to the heated surface with increasing heat flux as a result of the decrease in relative permeability of the partially saturated wick.

  18. Surface modification of nanoparticles for radiation curable acrylate clear coatings

    NASA Astrophysics Data System (ADS)

    Bauer, F.; Gläsel, H.-J.; Hartmann, E.; Bilz, E.; Mehnert, R.

    2003-08-01

    To obtain transparent, scratch and abrasion resistant coatings a high content of nanosized silica and alumina filler was embedded in radiation-curable acrylate formulations by acid catalyzed silylation using trialkoxysilanes. 29SiMAS NMR and MALDI-TOF mass spectrometry were employed to elucidate the structure of the surface-grafted methacryloxypropyl-, vinyl- and n-propyl-trimethoxysilane. In accordance with NMR findings, MALDI-TOF MS showed highly condensed oligomeric siloxanes of more than 20 monomeric silane units. A ladder-like structure of bound polysiloxanes is proposed rather than a simplified picture of tridentate silane bonding. Hence, silane coupling agents do not only modify the chemical nature of the filler surface but also strongly effect the rheological properties of the acrylate nanodispersions.

  19. Embroidered and surface coated polycaprolactone-co-lactide scaffolds

    PubMed Central

    Rentsch, Barbe; Bernhardt, Ricardo; Scharnweber, Dieter; Schneiders, Wolfgang; Rammelt, Stefan; Rentsch, Claudia

    2012-01-01

    Tissue engineering and regenerative techniques targeting bone include a broad range of strategies and approaches to repair, augment, replace or regenerate bone tissue. Investigations that are aimed at optimization of these strategies until clinical translation require control of systemic factors as well as modification of a broad range of key parameters. This article reviews a possible strategy using a tissue engineering approach and systematically describes a series of experiments evaluating the properties of an embroidered and surface coated polycaprolactone-co-lactide scaffold being considered as bone graft substitute for large bone defects. The scaffold design and fabrication, the scaffolds properties, as well as its surface modification and their influence in vitro are evaluated, followed by in vivo analysis of the scaffolds using orthotopic implantation models in small and large animals. PMID:23507867

  20. Self-cleaning antimicrobial surfaces by bio-enabled growth of SnO2 coatings on glass

    NASA Astrophysics Data System (ADS)

    André, Rute; Natalio, Filipe; Tahir, Muhammad Nawaz; Berger, Rüdiger; Tremel, Wolfgang

    2013-03-01

    Conventional vapor-deposition techniques for coatings require sophisticated equipment and/or high-temperature resistant substrates. Therefore bio-inspired techniques for the fabrication of inorganic coatings have been developed in recent years. Inspired by the biology behind the formation of the intricate skeletons of diatoms orchestrated by a class of cationic polyamines (silaffins) we have used surface-bound spermine, a naturally occurring polyamine, to promote the fast deposition of homogeneous, thin and transparent biomimetic SnO2 coatings on glass surfaces. The bio-enabled SnO2 film is highly photoactive, i.e. it generates superoxide radicals (O2&z.rad;-) upon sunlight exposure resulting in a strong degradation of organic contaminants and a strong antimicrobial activity. Upon illumination the biomimetic SnO2 coating exhibits a switchable amphiphilic behavior, which - in combination with its photoactivity - creates a self-cleaning surface. The intrinsic self-cleaning properties could lead to the development of new protective, antifouling coatings on various substrates.Conventional vapor-deposition techniques for coatings require sophisticated equipment and/or high-temperature resistant substrates. Therefore bio-inspired techniques for the fabrication of inorganic coatings have been developed in recent years. Inspired by the biology behind the formation of the intricate skeletons of diatoms orchestrated by a class of cationic polyamines (silaffins) we have used surface-bound spermine, a naturally occurring polyamine, to promote the fast deposition of homogeneous, thin and transparent biomimetic SnO2 coatings on glass surfaces. The bio-enabled SnO2 film is highly photoactive, i.e. it generates superoxide radicals (O2&z.rad;-) upon sunlight exposure resulting in a strong degradation of organic contaminants and a strong antimicrobial activity. Upon illumination the biomimetic SnO2 coating exhibits a switchable amphiphilic behavior, which - in combination with its

  1. Advancements in organic antireflective coatings for dual-damascene processes

    NASA Astrophysics Data System (ADS)

    Deshpande, Shreeram V.; Shao, Xie; Lamb, James E., III; Brakensiek, Nickolas L.; Johnson, Joe; Wu, Xiaoming; Xu, Gu; Simmons, William J.

    2000-06-01

    Dual Damascene (DD) process has been implemented in manufacturing semiconductor devices with smaller feature sizes (organic material such as a bottom anti- reflective coating (BARC) is used, then the resist thickness variations are minimized thus enhancing the resolution and CD control in trench patterning. Via fill organic BARC materials can also act as etch blocks at the base of the via to protect the substrate from over etch. In this paper we review the important role of via fill organic BARCs in improving the efficiency of via first DD process now being implemented in semiconductor manufacturing.

  2. New graphene fiber coating for volatile organic compounds analysis.

    PubMed

    Zhang, GuoJuan; Guo, XiaoXi; Wang, ShuLing; Wang, XueLan; Zhou, YanPing; Xu, Hui

    2014-10-15

    In the work, a novel graphene-based solid phase microextraction-gas chromatography/mass spectrometry method was developed for the analysis of trace amount of volatile organic compounds in human exhaled breath vapor. The graphene fiber coating was prepared by a one-step hydrothermal reduction reaction. The fiber with porous and wrinkled structure exhibited excellent extraction efficiency toward eight studied volatile organic compounds (two n-alkanes, five n-aldehydes and one aromatic compound). Meanwhile, remarkable thermal and mechanical stability, long lifespan and low cost were also obtained for the fiber. Under the optimal conditions, the developed method provided low limits of detection (1.0-4.5ngL(-1)), satisfactory reproducibility (3.8-13.8%) and acceptable recoveries (93-122%). The method was applied successfully to the analysis of breath samples of lung cancer patients and healthy individuals. The unique advantage of this approach includes simple setup, non-invasive analysis, cost-efficient and sufficient sensitivity. The proposed method supply us a new possibility to monitor volatile organic compounds in human exhaled breath samples. PMID:25171504

  3. Surface properties of semi-synthetic enteric coating films: Opportunities to develop bio-based enteric coating films for colon- targeted delivery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the surface properties of the semi-synthetic enteric coating materials for potential colon- targeted bioactive delivery. The enteric coating materials were produced by combining nanoscale resistant starch, pectin, and carboxymethylcellulose. The surface properties of the co...

  4. ABIOTIC ORGANIC REACTIONS AT MINERAL SURFACES

    EPA Science Inventory

    Abiotic organic reactions, such as hydrolysis, elimination, substitution, redox, and polymerization reactions, can be influenced by surfaces of clay and primary minerals, and of metal oxides. This influence is due to adsorption of the reactants to surface Lewis and Bronsted sites...

  5. Pb, Cu, and Zn distributions at humic acid-coated metal-oxide surfaces

    NASA Astrophysics Data System (ADS)

    Wang, Yingge; Michel, F. Marc; Choi, Yongseong; Eng, Peter J.; Levard, Clement; Siebner, Hagar; Gu, Baohua; Bargar, John R.; Brown, Gordon E.

    2016-09-01

    Mineral surfaces are often coated by natural organic matter (NOM), which has a major influence on metal-ion sorption and sequestration because of the abundance of binding sites in such coatings and the changes they cause in local nanoscale environments. The effects of NOM coatings on mineral surfaces are, however, still poorly understood at the molecular level due to the complexity of these systems. In this study, we have applied long-period X-ray standing wave-fluorescence yield (LP-XSW-FY) spectroscopy to measure the partitioning of naturally present Cu(II) (0.0226%), Zn(II) (0.009%), and Pb(II) (∼0.0004%) between Elliott Soil Humic Acid (ESHA) coatings and three model single-crystal metal-oxide substrates: α-Al2O3 (0 0 0 1), α-Al2O3 (1 -1 0 2), and α-Fe2O3 (0 0 0 1). The competitive sorption effects among these metal ions for binding sites in the ESHA coatings and on the metal-oxide surfaces were investigated as a function of reaction time, calcium content, and solution pH. Pb(II) ions present in the ESHA coatings were found to redistribute to reactive α-Al2O3 (1 -1 0 2) and α-Fe2O3 (0 0 0 1) surfaces after 3 h of reaction (pH = 6.0, [Ca(II)] = 2 mM). Pb(II) partitioning onto these reactive metal-oxide surfaces increased with increasing reaction time (up to 7 d). In addition, the partitioning of Cu(II) and Zn(II) from the ESHA coating to the α-Fe2O3 (0 0 0 1) substrate increased slightly with reaction time (2.4% and 3.7% for Cu(II) and Zn(II), respectively, after 3 h and 6.4% and 7.7% for Cu(II) and Zn(II), respectively, after 72 h of reaction time). However, no changes in the partitioning of Cu(II) and Zn(II) onto the α-Al2O3 (1 -1 0 2) surface were observed with increasing reaction time, suggesting that these ions strongly complex with functional groups in the ESHA coatings. Similar results were obtained for Cu(II) and Zn(II) on the ESHA-coated α-Al2O3 (1 -1 0 2) surfaces in samples without the addition of calcium. However, the amounts of Pb

  6. Surface modifications and surface-protective coatings analyzed by means of thermal waves (invited) (abstract)

    NASA Astrophysics Data System (ADS)

    Bein, B. K.; Fotsing, J. L. N.; Gibkes, J.; Delgadillo-Holtfort, I.; Dietzel, D.; Pelzl, J.

    2003-01-01

    The depth profiles of the thermophysical properties of alloy systems, for example, shape memory alloys (NiTi), steel, and tool steel, can vary considerably due to rolling, surface machining, heat treatment, mechanical wear, and erosion. The same is true for coated tool steel samples, which show variations of the effective thermal depth profiles due to the effects of substrate preparation and deposition of the coatings, for example, plasma-etching, arc erosion, nitriding, chemical vapor deposition (CVD), physical vapor deposition (PVD), sputter deposition, and plasma spraying. In this work we present a large variety of measured effective thermal depth profiles. In a first step, we identify the effects of coating deposition and substrate preparation on the measured depth profiles. In a second step, we identify and try to quantify the effects of mechanical wear and erosion of both coated and uncoated surface. To this finality, the signals, which have been measured with the help of IR radiometry as a function of the modulation frequency, have been calibrated with reference signals measured for homogeneous samples of glassy carbon. The normalized amplitudes and phases have been approximated using layer models, mainly the two- and three-layer model with an opaque first layer, with respect to both the visible and the IR spectrum. Additionally, the signals measured for different coatings have been normalized against each other. By this latter calibration procedure, even smaller details and differences of coating deposition and substrate preparation can be identified, as well as the effects of wear and surface erosion. The virgin coated samples normally can well be described by the two-layer model, and the thermal transport parameters of the coatings as a whole can be determined quantitatively with rather good reliability (Ref. 1). The deviations from the two-layer model, which can be related to details of the deposition process, for example, to gradient layers or bond

  7. Effect of cathodic polarization on coating doxycycline on titanium surfaces.

    PubMed

    Geißler, Sebastian; Tiainen, Hanna; Haugen, Håvard J

    2016-06-01

    Cathodic polarization has been reported to enhance the ability of titanium based implant materials to interact with biomolecules by forming titanium hydride at the outermost surface layer. Although this hydride layer has recently been suggested to allow the immobilization of the broad spectrum antibiotic doxycycline on titanium surfaces, the involvement of hydride in binding the biomolecule onto titanium remains poorly understood. To gain better understanding of the influence this immobilization process has on titanium surfaces, mirror-polished commercially pure titanium surfaces were cathodically polarized in the presence of doxycycline and the modified surfaces were thoroughly characterized using atomic force microscopy, electron microscopy, secondary ion mass spectrometry, and angle-resolved X-ray spectroscopy. We demonstrated that no hydride was created during the polarization process. Doxycycline was found to be attached to an oxide layer that was modified during the electrochemical process. A bacterial assay using bioluminescent Staphylococcus epidermidis Xen43 showed the ability of the coating to reduce bacterial colonization and planktonic bacterial growth. PMID:27040230

  8. The surface energy of various biomaterials coated with adhesion molecules used in cell culture.

    PubMed

    Harnett, Elaine M; Alderman, John; Wood, Terri

    2007-03-15

    This study calculates the surface energy of polystyrene tissue culture plastic, silicon, silicon dioxide and indium tin oxide, all of which have applications in tissue culture. The adhesion molecules: collagen, fibronectin, poly-L-ornithine and poly-D-lysine, were coated onto these various surfaces, and the surface energy of the coated substrates calculated. Coating with fibronectin was found to produce a monopolar acidic surface while poly-D-lysine, poly-L-ornithine and collagen coatings were found to produce monopolar basic surfaces. The calculated surface energy components of the coated materials were then used to give a quantitative determination of the magnitude of their hydrophobicity. It was concluded that collagen, polylysine and polyornithine could provide a hydrophobic or hydrophilic surface depending on the underlying substrates they were coated on. The measurement obtained for fibronectin, unlike the other adhesion molecules, was independent of the underlying surface and remained hydrophobic on all substrates tested. Wetting experiments were carried out on the coated substrates, using the tissue culture medium Dulbeccos modified eagles medium, both containing and not containing serum proteins, and saline solution. These liquids that are commonly used in tissue culture, were then used to provide information how these liquids behave on various substrates coated with the adhesion molecules. Results show that fibronectin coated surfaces represent the most phobic surface for all three liquids. The findings of this study can be used in cell manipulation studies and provide a valuable data set for the biomedical and research industries. PMID:17207976

  9. Optimizing the coating process of organic actinide extractants on magnetically assisted chemical separation particles.

    SciTech Connect

    Buchholz, B. A.; Tuazon, H. E.; Kaminski, M. D.; Aase, S. B.; Nunez, L.; Vandegrift, G. F.; Chemical Engineering; LLNL; California State Polytechnic Univ. at Pomona; Univ. of Illinois; Univ. of Illinois at Chicago

    1997-01-01

    The coatings of ferromagnetic-charcoal-polymer microparticles (1-25 gm) with organic extractants specific for actinides were optimized for use in the magnetically assisted chemical separation (MACS) process. The organic extractants, octyl (phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in tributyl phosphate (TBP), coated the particles when a carrier organic solvent was evaporated. Coated particles were heated in an oven overnight to drive off any remaining carrier solvent and fix the extractants on the particles. Partitioning coefficients for americium obtained with the coated particles routinely reached 3000-4000 ml g-1, approximately 10 times the separation efficiency observed with the conventional solvent extraction system using CMPO and TBP.

  10. Organic-aqueous crossover coating process for the desmopressin orally disintegrating microparticles.

    PubMed

    Kim, Ju-Young; Hwang, Kyu-Mok; Park, Chun-Woong; Rhee, Yun-Seok; Park, Eun-Seok

    2015-02-01

    The purpose of the present study was to prepare desmopressin orally disintegrating microparticles (ODMs) using organic-aqueous crossover coating process which featured an organic sub-coating followed by an aqueous active coating. Sucrose beads and hydroxypropyl cellulose (HPC) were used as inert cores and a coating material, respectively. Characterizations including size distribution analysis, in-vitro release studies and in-vitro disintegration studies were performed. A pharmacokinetic study of the ODMs was also conducted in eight beagle dogs. It was found that sucrose beads should be coated using organic solvents to preserve their original morphology. For the active coating, the aqueous coating solution should be used for drug stability. When sucrose beads were coated using organic-aqueous crossover coating process, double-layer ODMs with round shapes were produced with detectable impurities below limit of US Pharmacopeia. The median size of ODMs was 195.6 μm, which was considered small enough for a good mouthfeel. The ODMs dissolved in artificial saliva within 15 s because of hydrophilic materials including sucrose and HPC in the ODMs. Because of its fast-dissolving properties, 100% release of the drug was reached within 5 min. Pharmacokinetic parameters including Cmax and AUC24 indicated bioequivalence of the ODMs and the conventional immediate release tablets. Therefore, by using the organic-aqueous crossover coating process, double-layer ODMs were successively prepared with small size, round shapes and good drug stability. PMID:24252109