Science.gov

Sample records for biphasic thin coatings

  1. Super Thin Ceramic Coatings

    NASA Video Gallery

    New technology being developed at NASA's Glenn Research Center creates super thin ceramic coatings on engine components. The Plasma Spray – Physical Vapor Deposition (PS-PVD) rig uses a powerful ...

  2. Bi-phase transition diagrams of metallic thin multilayers

    SciTech Connect

    Li, J.C.; Liu, W.; Jiang, Q. . E-mail: jiangq@jlu.edu.cn

    2005-02-01

    Phase transitions of metallic multilayers induced by differences in interface energy are considered thermodynamically, based on a thermodynamic model for interface energy and the Goldschmidt premise for lattice contraction. Bi-phase transition diagrams of Co/Cr, Zr/Nb, Ti/Nb and Ti/Al multilayers are constructed, which are in agreement with experimental results.

  3. Thin film ion conducting coating

    DOEpatents

    Goldner, Ronald B.; Haas, Terry; Wong, Kwok-Keung; Seward, George

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  4. 11 alpha-Hydroxylation of progesterone in biphasic media using alginate-entrapped Aspergillus ochraceus gel beads coated with polyurea.

    PubMed

    Houng, J Y; Chiang, W P; Chen, K C; Tiu, C

    1994-06-01

    A novel cell-immobilization technique was developed in this study for increasing substrate partition to the gel matrix by coating a polyurea thin layer on the surface of Ca-alginate beads. The proposed method was simple and could be performed under mild conditions. The bioconversion of progesterone to 11 alpha-hydroxyprogesterone with these polyurea-coating alginate-entrapped Aspergillus ochraceus cells was investigated using different organic solvents in biphasic media. The reaction medium of ethyl acetate could markedly enhance the bioconversion rate with the existence of a hydrophobic layer, most likely resulting from the increasing partition of substrate to gel matrix. Bioconversion with higher substrate concentration was possible using an ethyl acetate-water medium. The conversion rate increased almost linearly with increasing substrate concentration from 10 to 80 g l-1. The rate with 80 g l-1 progesterone increased up to six times greater than the rate with the immobilized cells without coating, and also exhibited a much higher rate than that reported in the literature.

  5. Thin CVD Coating Protects Titanium Aluminide Alloys

    NASA Technical Reports Server (NTRS)

    Clark, Ronald; Wallace, Terryl; Cunnington, George; Robinson, John

    1994-01-01

    Feasibility of using very thin CVD coatings to provide both protection against oxidation and surfaces of low catalytic activity for thin metallic heat-shield materials demonstrated. Use of aluminum in compositions increases emittances of coatings and reduces transport of oxygen through coatings to substrates. Coatings light in weight and applied to foil-gauge materials with minimum weight penalties.

  6. Thin film-coated polymer webs

    DOEpatents

    Wenz, Robert P.; Weber, Michael F.; Arudi, Ravindra L.

    1992-02-04

    The present invention relates to thin film-coated polymer webs, and more particularly to thin film electronic devices supported upon a polymer web, wherein the polymer web is treated with a purifying amount of electron beam radiation.

  7. Effect of nano-hydroxyapatite coating on the osteoinductivity of porous biphasic calcium phosphate ceramics

    PubMed Central

    2014-01-01

    Background Porous biphasic calcium phosphate (BCP) ceramics exhibit good biocompatibility and bone conduction but are not inherently osteoinductive. To overcome this disadvantage, we coated conventional porous BCP ceramics with nano-hydroxyapatite (nHA). nHA was chosen as a coating material due to its high osteoinductive potential. Methods We used a hydrothermal deposition method to coat conventional porous BCP ceramics with nHA and assessed the effects of the coating on the physical and mechanical properties of the underlying BCP. Next, its effects on mesenchymal stem cell (MSC) attachment, proliferation, viability, and osteogenic differentiation were investigated. Results nHA formed a deposited layer on the BCP surface, and synthesized nHA had a rod-like shape with lengths ranging from ~50–200 nm and diameters from ~15–30 mm. The nHA coating did not significantly affect the density, porosity, flexural strength, or compressive strength of the underlying BCP (P > 0.1). Scanning electron microscopy showed MSC attachment to the scaffolds, with a healthy morphology and anchorage to nHA crystals via cytoplasmic processes. The densities of MSCs attached on BCP and nHA-coated BCP scaffolds were 62 ± 26 cells/mm2 and 63 ± 27 cells/mm2 (P > 0.1), respectively, after 1 day and 415 ± 62 cells/mm2 and 541 ± 35 cells/mm2 (P < 0.05) respectively, after 14 days. According to an MTT assay, MSC viability was higher on nHA-coated BCP scaffolds than on BCP scaffolds (P < 0.05). In addition, MSCs on nHA-coated BCP scaffolds produced more alkaline phosphatase, collagen type I, and osteocalcin than MSCs on BCP scaffolds (P < 0.05). Conclusions Our results demonstrate that BCP scaffolds coated with nHA were more conducive for MSC adhesion, proliferation, and osteogenic differentiation than conventional, uncoated BCP scaffolds, indicating that nHA coating can enhance the osteoinductive potential of BCP ceramics, making this material more

  8. Analysis of Hard Thin Film Coating

    NASA Technical Reports Server (NTRS)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  9. Analysis of Hard Thin Film Coating

    NASA Technical Reports Server (NTRS)

    Shen, Dashen

    1998-01-01

    Marshall Space Flight Center (MSFC) is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using Electron Cyclotron Resonance Chemical Vapor Deposition (ECRCVD) to deposit hard thin film on stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  10. Thin coatings and films hardness evaluation

    NASA Astrophysics Data System (ADS)

    Matyunin, V. M.; Marchenkov, A. Yu; Demidov, A. N.; Karimbekov, M. A.

    2016-10-01

    The existing thin coatings and films hardness evaluation methods based on indentation with pyramidal indenter on various scale levels are expounded. The impact of scale factor on hardness values is performed. The experimental verification of several existing hardness evaluation methods regarding the substrate hardness value and the “coating - substrate” composite hardness value is made.

  11. Paper-Thin Coating Offers Maximum Protection

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Wessex Incorporated has recently taken a technology that was originally developed for NASA as a protective coating for ceramic materials used in heatshields for space vehicles, and modified it for use in applications such as building materials, machinery, and transportation. The technology, developed at NASA Ames Research Center as a protective coating for flexible ceramic composites (PCC), is environmentally safe, water-based, and contains no solvents. Many other flame-retardant materials contain petroleum-based components, which can produce toxic smoke under flame. Wessex versions of PCC can be used to shield ceramics, wood, plasterboard, steel, plastics, fiberglass, and other materials from catastrophic fires. They are extraordinarily tough and exhibit excellent resistance to thermal shock, vibration, abrasion, and mechanical damage. One thin layer of coating provides necessary protection and allows for flexibility while avoiding excessive weight disadvantages. The coating essentially reduces the likelihood of the underlying material becoming so hot that it combusts and thus inhibits the "flashover" phenomenon from occurring.

  12. Graphene: Atomically thin protective coating

    NASA Astrophysics Data System (ADS)

    Prasai, Dhiraj; Bolotin, Kirill; Tuberquia, Juan; Harl, Robert; Jennings, Kane

    2011-03-01

    We explore the properties of graphene as a cathodic coating to protect copper substrates from oxidation and further corrosion. High-quality and large area graphene films are grown on copper substrates by chemical vapor deposition. Samples were thermally oxidized in an oxygen-rich environment. X-ray photoelectron spectroscopy (XPS) characterization of a Graphene/copper and bare copper samples reveals the absence of oxidized copper at the graphene/copper interface indicating that the graphene monolayer protects the underlying copper. We also determine the protective properties of graphene in aqueous media using electrochemical characterization techniques. First, we use Electrochemical Impedance Spectroscopy (EIS) to show that graphene coated substrates lower frequencies (1Hz) exhibit impedance values 2 orders of magnitude higher compared to bare Cu substrates. Cyclic voltammetry also shows that a monolayer of graphene significantly reduces the oxygen reduction, thus exhibiting little charge transfer at the solid-liquid interface. Finally, we use Tafel analysis to estimate that the corrosion rate exhibited by Graphene/Cu is ~ 7 times lower than that of bare Cu substrates.

  13. Improvement of osteogenic potential of biphasic calcium phosphate bone substitute coated with synthetic cell binding peptide sequences

    PubMed Central

    Choi, Hyunmin; Park, Nho-Jae; Jamiyandorj, Otgonbold; Hong, Min-Ho; Oh, Seunghan; Park, Young-Bum

    2012-01-01

    Purpose The aim of this study was to evaluate the improvement of osteogenic potential of biphasic calcium phosphate (BCP) bone substitute coated with synthetic cell-binding peptide sequences in a standardized rabbit sinus model. Methods Standardized 6-mm diameter defects were created bilaterally on the maxillary sinus of ten male New Zealand white rabbits, receiving BCP bone substitute coated with synthetic cell binding peptide sequences on one side (experimental group) and BCP bone substitute without coating (control group) on the other side. Histologic and histomorphometric analysis of bone formation was carried out after a healing period of 4 or 8 weeks. Results Histological analysis revealed signs of new bone formation in both experimental groups (4- and 8-week healing groups) with a statistically significant increase in bone formation in the 4-week healing group compared to the control group. However, no statistically significant difference in bone formation was found between the 8-week healing group and the control group. Conclusions This study found that BCP bone substitute coated with synthetic cell-binding peptide sequences enhanced osteoinductive potential in a standardized rabbit sinus model and its effectiveness was greater in the 4-week healing group than in the 8-week healing group. PMID:23185697

  14. Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

    PubMed

    Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

    2008-02-28

    The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

  15. Characterization and in vitro evaluation of biphasic calcium pyrophosphate-tricalciumphosphate radio frequency magnetron sputter coatings.

    PubMed

    Takahashi, K; van den Beucken, J J J P; Wolke, J G C; Hayakawa, T; Nishiyama, N; Jansen, J A

    2008-03-01

    The objective of this study was to characterize the physicochemical, dissolution, and osteogenic properties of radio frequency magnetron sputtered dicalcium pyrophosphate/tricalciumphosphate (Pyro/TCP) and hydroxylapatite (HA) coatings. Therefore Pyro/TCP and HA coatings were deposited on grit-blasted titanium discs. The results showed that the deposited coatings were amorphous and changed into a crystalline structure after IR heat-treatment of 550 degrees C for HA and 650 degrees C for Pyro/TCP. Heat-treated HA coatings appeared to be stable during immersion in simulated body fluid (SBF), that is no changes in the XRD pattern were observed. Also, no dissolution of the coating was observed by scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) revealed that the Ca/P ratio of the HA coatings remained constant during SBF immersion. On the other hand, the heat-treated Pyro/TCP coatings showed a surface reaction of calcium pyrophosphate into a beta-tricalcium phosphate phase during SBF immersion. This was confirmed by EDS analysis. Rat bone marrow-derived osteoblast-like cells cultured on the heat-treated substrates showed that cell proliferation and differentiation occurred on both types of bioceramic coatings. No significant differences for proliferation and early differentiation were observed between cells cultured on heat-treated Pyro/TCP and HA at individual time points. However, osteocalcin expression, a late marker for osteoblast-like cell differentiation, was significantly increased after 12 days of culture on HA-coatings. These results were confirmed by SEM observations and suggest increased osteogenic properties for HA-coatings over Pyro/TCP-coatings. Additional research is necessary to obtain conclusive evidence on the in vivo osteogenic capacity of Pyro/TCP coatings.

  16. Temperature-dependent biphasic shrinkage of lipid-coated bubbles in ultrasound.

    PubMed

    Cox, Debra J; Thomas, James L

    2013-04-09

    Lipid-coated microbubbles and emulsions are of interest as possible ultrasound-mediated drug delivery vehicles and for their interesting behaviors and fundamental properties. We and others have noted that bubbles coated with the long chain saturated phospholipid distearoylphosphatidylcholine (DSPC) rapidly shrink to a quasistable size when repeatedly insonated with short ultrasound pulses; such stability may adversely affect the bubble's subsequent ability to deliver its pharmacological cargo. Bubbles coated with the unsaturated lipid dioleoylphosphatidylcholine (DOPC) did not show stability but did undergo an abrupt change from rapid initial shrinkage to a slow persistent shrinkage, leading ultimately to dissolution or dispersion. As DOPC and DSPC differ not only in chain saturation but also phase behavior, we performed additional studies using dimyristoyl PC (DMPC) as a coat lipid and controlled the solution temperature to study bubble behavior on exposure to repeated ultrasound pulses for the same coat, in both fluid and gel phases. We find, first, that essentially all bubbles show an initially rapid shrinkage, in which gas loss exceeds the limit imposed by gas diffusion into the surrounding medium; this rapid shrinkage may be evidence of nanoscopic bubble fragmentation. Second, upon reaching a fraction of their initial size, bubbles begin a slower shrinkage with a shrinkage rate that depends on the resting phase state of the coat lipid: fluid DMPC monolayers give a more rapid shrinkage than gel phase. DOPC-coated bubbles showed no temperature-dependent responses in the same temperature range. The results are especially interesting in that bubble compression during the pulse is likely to adiabatically heat the bubble and fluidize the coat, regardless of its initial phase state; thus, some structural feature of the resting coat, such as defect lines in the gel phase, may be important in the subsequent response to the ~3 μs ultrasound pulse.

  17. Infrared control coating of thin film devices

    DOEpatents

    Berland, Brian Spencer; Stowell, Jr., Michael Wayne; Hollingsworth, Russell

    2017-02-28

    Systems and methods for creating an infrared-control coated thin film device with certain visible light transmittance and infrared reflectance properties are disclosed. The device may be made using various techniques including physical vapor deposition, chemical vapor deposition, thermal evaporation, pulsed laser deposition, sputter deposition, and sol-gel processes. In particular, a pulsed energy microwave plasma enhanced chemical vapor deposition process may be used. Production of the device may occur at speeds greater than 50 Angstroms/second and temperatures lower than 200.degree. C.

  18. Preparation, Characterization and in vivo Evaluation of Simple Monolithic Ethylcellulose-coated Pellets Containing Topiramate with Biphasic Release Characteristics.

    PubMed

    Gong, Wei; Wang, Yuli; Shao, Shuai; Xie, Si; Shan, Li; Yang, Meiyan; Gao, Chunsheng; Zhong, Wu

    2016-01-01

    In our previous study, polyvinylpyrrolidone (PVP) was used both as a binder and a pore-former to prepare ethylcellulose (EC)-coated pellets to deliver topiramate (TPM) for a controlled release profile. The objective of this work was to further optimize the formulation and evaluate the in vivo profiles of TPM sustained-release pellets. Similar to the previous formulation with no binder, the in vitro drug release of TPM sustained-release pellets with 50% PVP binder in drug layer was sensitive to pore-former PVP level ranged from 27.0% to 29.0%. The higher the level of PVP was, the quicker release rate in vitro was. Moreover, when the proportion of poreformer PVP decreased, the Cmax decreased, and the tmax and mean residence time of TPM coated pellets were both prolonged. The in vitro release profile of optimal formulation showed biphasic release characteristics similar to reference formulation Trokendi XR(®), i.e., involving immediate release of TPM in initial release stage followed by a sustained release up to 24 h. Moreover, the impact of the pH of release medium on the drug release rate of TPM sustained-release pellets was not significant. The release mechanism of TPM from the sustained-release pellets might be the interaction of diffusion (coating-film) and corrosion (drug layer). The in vivo pharmacokinetics results showed the TPM sustained-release pellets had the similar in vivo pattern compared with Trokendi XR(®). These studies provide valuable basis for further development of TPM sustained-release pellets.

  19. Characterization of Thin Films and Coatings

    SciTech Connect

    Baer, Donald R.; Thevuthasan, Suntharampillai

    2010-01-01

    Just as the numbers and types of thin films have grown dramatically, the needs and approaches for their characterization have also expanded significantly. Adequate characterization of a film or coating depends on the process to create the coating as well as the planned or potential application(s) and expected lifetime. Characterization of a coating or film necessarily requires application of methods that determine properties of the coating and not primarily the substrate. This places some focus on methods that determine properties of layers and not "bulk" material. However, the increasing importance of micro- and nano-structures in coatings and films places an increased importance in methods with high spatial resolution. The growing use of organic films and coatings and the importance of molecular functionalization of inorganic surfaces increase the importance for different types of molecular characterization tools. In most circumstances appropriate characterization requires use of a combination of tools. The purpose of this chapter is to provide an introduction to the basic methods and overview applications for some of the most important tools for characterization of films, coatings and surfaces. The chapter will be organized in six sections: • Technique Overview – This section provides a high level summary of the types of information that can be obtained by different methods and includes information about their sensitivity and resolution. • Incident Photon Methods – Techniques involving incident photons are described and some brief examples of application are shown. Methods included are: x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), x-ray reflectivity (XRR), Fourier transform infra-red spectroscopy (FTIR), laser Raman spectroscopy, ellipsometry, and photoluminescence spectroscopy. • Incident Ion Methods - Methods initiated by ion irradiation are summarized including: Rutherford backscattering spectrometry (RBS), nuclear reaction

  20. Tailoring Thin Film-Lacquer Coatings for Space Application

    NASA Technical Reports Server (NTRS)

    Peters, Wanda C.; Harris, George; Miller, Grace; Petro, John

    1998-01-01

    Thin film coatings have the capability of obtaining a wide range of thermal radiative properties, but the development of thin film coatings can sometimes be difficult and costly when trying to achieve highly specular surfaces. Given any space mission's thermal control requirements, there is often a need for a variation of solar absorptance (Alpha(s)), emittance (epsilon) and/or highly specular surfaces. The utilization of thin film coatings is one process of choice for meeting challenging thermal control requirements because of its ability to provide a wide variety of Alpha(s)/epsilon ratios. Thin film coatings' radiative properties can be tailored to meet specific thermal control requirements through the use of different metals and the variation of dielectric layer thickness. Surface coatings can be spectrally selective to enhance radiative coupling and decoupling. The application of lacquer to a surface can also provide suitable specularity for thin film application without the cost and difficulty associated with polishing.

  1. Lithium battery electrodes with ultra-thin alumina coatings

    SciTech Connect

    Se-Hee, Lee; George, Steven M.; Cavanagh, Andrew S.; Yoon Seok, Jung; Dillon, Anne C.

    2015-11-24

    Electrodes for lithium batteries are coated via an atomic layer deposition process. The coatings can be applied to the assembled electrodes, or in some cases to particles of electrode material prior to assembling the particles into an electrode. The coatings can be as thin as 2 .ANG.ngstroms thick. The coating provides for a stable electrode. Batteries containing the electrodes tend to exhibit high cycling capacities.

  2. Porous biphasic calcium phosphate ceramics coated with nano-hydroxyapatite and seeded with mesenchymal stem cells for reconstruction of radius segmental defects in rabbits.

    PubMed

    Hu, Jianzhong; Yang, Zhiming; Zhou, Yongchun; Liu, Yong; Li, Kaiyang; Lu, Hongbin

    2015-11-01

    The osteoconduction of porous biphasic calcium phosphate (BCP) ceramics has been widely reported. In a previous study, we demonstrated that applying a nano-hydroxyapatite (nHA) coating enhances the osteoinductive potential of BCP ceramics, making these scaffolds more suitable for bone tissue engineering applications. The aim of the present study was to determine the effects of reconstructing radius defects in rabbits using nHA-coated BCP ceramics seeded with mesenchymal stem cells (MSCs) and to compare the bone regeneration induced by different scaffolds. Radius defects were created in 20 New Zealand rabbits, which were divided into four groups by treatment: porous BCP ceramics (Group A), nHA-coated porous BCP ceramics (Group B), porous BCP ceramics seeded with rabbit MSCs (Group C), and nHA-coated porous BCP ceramics seeded with rabbit MSCs (Group D). After in vitro incubation, the cell/scaffold complexes were implanted into the defects. Twelve weeks after implantation, the specimens were examined macroscopically and histologically. Both the nHA coating and seeding with MSCs enhanced the formation of new bone tissue in the BCP ceramics, though the osteoinductive potential of the scaffolds with MSCs was greater than that of the nHA-coated scaffolds. Notably, the combination of nHA coating and MSCs significantly improved the bone regeneration capability of the BCP ceramics. Thus, MSCs seeded into porous BCP ceramics coated with nHA may be an effective bone substitute to reconstruct bone defects in the clinic.

  3. Thin Film Metal Coated Fiber Optic Hydrophone Probe

    PubMed Central

    Gopinath, R.; Arora, P.; Gandhi, G.; Daryoush, A.S.; El-Sherif, M.; Lewin, P.A.

    2010-01-01

    The purpose of this work was to improve on sensitivity performance of fiber sensor employed as Fiber Optic Hydrophone Probe (FOHP) by nano-scale thin film gold coating. The fiber is designed to provide a uniform and spatial averaging free response up to 100 MHz by etching down to an active diameter of about 9 μm. The sensitivity performance of straight cleaved (i.e. full size core and cladding) uncoated, tapered uncoated and tapered thin film gold coated fiber sensors were compared in the frequency range of 1.5 MHz to 20 MHz in the presence of acoustic pressure amplitude levels of up to 6 MPa. An unprecedented voltage sensitivity of −245 dB re 1V/uPa (560 mV/ MPa) was measured for thin film gold coated FOHP by optimizing the gold coating thickness. PMID:19881652

  4. Thin film coating process using an inductively coupled plasma

    DOEpatents

    Kniseley, Richard N.; Schmidt, Frederick A.; Merkle, Brian D.

    1990-01-30

    Thin coatings of normally solid materials are applied to target substrates using an inductively coupled plasma. Particles of the coating material are vaporized by plasma heating, and pass through an orifice to a first vacuum zone in which the particles are accelerated to a velocity greater than Mach 1. The shock wave generated in the first vacuum zone is intercepted by the tip of a skimmer cone that provides a second orifice. The particles pass through the second orifice into a second zone maintained at a higher vacuum and impinge on the target to form the coating. Ultrapure coatings can be formed.

  5. Ultra-Thin Coatings Beautify Art

    NASA Technical Reports Server (NTRS)

    2013-01-01

    The craftsmen in the Roman Empire who constructed the Lycurgus Cup 17 centuries ago probably didn't think their artifact would survive for nearly 2,000 years as a prized possession. And they certainly couldn't have known that the technology they used to make it would eventually become an important part of space exploration. Carved from one solid mass, the cup is one of the few complete glass objects from that period, and the only one made from dichroic glass. Meaning "two-colored" in Greek, dichroic glass was originally created by adding trace amounts of gold and silver to a large volume of glass melt. The resulting medium partially reflects the light passing through it, causing an observer to see different colors depending on the direction of the light source. The Lycurgus Cup, for example, is famous for appearing green in daylight and red when lit at night, symbolic of the ripening grapes used to fill it with wine. NASA revitalized the production of dichroic glass in the 1950s and 1960s as a means of protecting its astronauts. Ordinary clear substances cannot protect human vision from the harsh rays of unfiltered sunlight, and everything from the human body to spacecraft sensors and computers are at risk if left unprotected from the radiation that permeates space. The microscopic amounts of metal present in dichroic glass make it an effective barrier against such harmful radiation. While the ancient manufacturing technique called for adding metals to glass melt, NASA developed a process in which metals are vaporized by electron beams in a vacuum chamber and then applied directly to surfaces in an ultra-thin film. The vapor condenses in the form of crystal structures, and the process is repeated for up to several dozen coatings. The resulting material, still only about 30 millionths of an inch thick, is sufficient to reflect radiation even while the glass, or polycarbonate, as in the case of space suit helmets, remains transparent to the human eye.

  6. Tailoring Thin Film-Lacquer Coatings for Space Applications

    NASA Technical Reports Server (NTRS)

    Peters, Wanda C.; Harris, George; Miller, Grace; Petro, John

    1998-01-01

    Thin film coatings have the capability of obtaining a wide range of thermal radiative properties, but the development of thin film coatings can sometimes be difficult and costly when trying to achieve highly specular surfaces. Given any space mission's then-nal control requirements, there is often a need for a variation of solar absorptance (alpha(sub s)), emittance (epsilon) and/or highly specular surfaces. The utilization of thin film coatings is one process of choice for meeting challenging thermal control requirements because of its ability to provide a wide variety of alpha(sub s)/epsilon ratios. Thin film coatings' radiative properties can be tailored to meet specific thermal control requirements through the use of different metals and the variation of dielectric layer thickness. Surface coatings can be spectrally selective to enhance radiative coupling and decoupling. The application of lacquer to a surface can also provide suitable specularity for thin film application without the cost and difficulty associated with polishing.

  7. Positron lifetime spectroscopy for investigation of thin polymer coatings

    NASA Technical Reports Server (NTRS)

    Singh, Jag J.; Sprinkle, Danny R.; Eftekhari, Abe

    1993-01-01

    In the aerospace industry, applications for polymer coatings are increasing. They are now used for thermal control on aerospace structures and for protective insulating layers on optical and microelectronic components. However, the effectiveness of polymer coatings depends strongly on their microstructure and adhesion to the substrates. Currently, no technique exists to adequately monitor the quality of these coatings. We have adapted positron lifetime spectroscopy to investigate the quality of thin coatings. Results of measurements on thin (25-micron) polyurethane coatings on aluminum and steel substrates have been compared with measurements on thicker (0.2-cm) self-standing polyurethane discs. In all cases, we find positron lifetime groups centered around 560 psec, which corresponds to the presence of 0.9-A(exp 3) free-volume cells. However, the number of these free-volume cells in thin coatings is larger than in thick discs. This suggests that some of these cells may be located in the interfacial regions between the coatings and the substrates. These results and their structural implications are discussed in this report.

  8. Nano-enabled tribological thin film coatings: global patent scenario.

    PubMed

    Sivudu, Kurva S; Mahajan, Yashwant R; Joshi, Shrikant V

    2014-01-01

    The aim of this paper is to present current status and future prospects of nano-enabled tribological thin film coatings based on worldwide patent landscape analysis. The study also presents an overview of technological trends by carrying out state-of-the-art literature analysis, including survey of corporate websites. Nanostructured tribological coatings encompass a wide spectrum of nanoscale microstructures, including nanocrystalline, nanolayered, nano-multilayered, nanocomposite, nanogradient structures or their unique combinations, which are composed of single or multi-component phases. The distinct microstructural features of the coatings impart outstanding tribological properties combined with multifunctional attributes to the coated components. Their unique combination of remarkable properties make them ideal candidates for a wide range of applications in diverse fields such as cutting and metalworking tools, biomedical devices, automotive engine components, wear parts, hard disc drives etc. The patent landscape analysis has revealed that nano-enabled tribological thin film coatings have significant potential for commercial applications in view of the lion's share of corporate industry in patenting activity. The largest patent portfolio is held by Japan followed by USA, Germany, Sweden and China. The prominent players involved in this field are Mitsubishi Materials Corp., Sandvik Aktiebolag, Hitachi Ltd., Sumitomo Electric Industries Ltd., OC Oerlikon Corp., and so on. The outstanding potential of nanostructured thin film tribological coatings is yet to be fully unravelled and, therefore, immense opportunities are available in future for microstructurally engineered novel coatings to enhance their performance and functionality by many folds.

  9. Laser Damage in Thin Film Optical Coatings

    DTIC Science & Technology

    1992-07-01

    OTHER RELEVANT ISSUES The damage thresholds of refractory oxides used as AR coatings for alexandrite laser rods were determined and measured by...used and a limited number of TiO 2/SiO2 coatings were put on alexandrite substrates. Single layer AR coatings of MgF2 and NaAIF 6 were also tested for...measurements were made using an alexandrite laser at a wavelength of 790 nm. with a pulse duration of 200 nsec at 30Hz for 2 seconds. The near spot

  10. Thin film coatings for improved alpha/epi

    NASA Technical Reports Server (NTRS)

    Krisl, M. E.; Sachs, I. M.

    1985-01-01

    New thin film coatings were developed for fused silica, ceria doped glass, and Corning 0211 microsheet which provide increased emissivity and/or decreased solar absorption. Emissivity is enhanced by suppression of the reststrahlen reflectance and solar absorption is reduced by externally reflecting the ultraviolet portion of the solar spectrum. Optical properties of these coatings make them suitable for both solar cell cover and thermal control mirror applications. Measurements indicate equivalent environmental performance to conventional solar cell cover and thermal control mirror products.

  11. Coating Thin Mirror Segments for Lightweight X-ray Optics

    NASA Technical Reports Server (NTRS)

    Chan, Kai-Wing; Sharpe, Marton V.; Zhang, William; Kolosc, Linette; Hong, Melinda; McClelland, Ryan; Hohl, Bruce R.; Saha, Timo; Mazzarellam, James

    2013-01-01

    Next generations lightweight, high resolution, high throughput optics for x-ray astronomy requires integration of very thin mirror segments into a lightweight telescope housing without distortion. Thin glass substrates with linear dimension of 200 mm and thickness as small as 0.4 mm can now be fabricated to a precision of a few arc-seconds for grazing incidence optics. Subsequent implementation requires a distortion-free deposition of metals such as iridium or platinum. These depositions, however, generally have high coating stresses that cause mirror distortion. In this paper, we discuss the coating stress on these thin glass mirrors and the effort to eliminate their induced distortion. It is shown that balancing the coating distortion either by coating films with tensile and compressive stresses, or on both sides of the mirrors is not sufficient. Heating the mirror in a moderately high temperature turns out to relax the coated films reasonably well to a precision of about a second of arc and therefore provide a practical solution to the coating problem.

  12. Laser powder coating by multi-thin-layer technics

    NASA Astrophysics Data System (ADS)

    Sepold, Gerd; Becker, Reinhard

    1990-10-01

    The laser beam is an interesting tool for production of thin surface layers. The energy input is locally limited thus leading to a snall heat loading of the substrate. The geometric dinensions of the coatings are small as compared to conventional thermal technics like surface melting and coating. In the following the multithin-layer technique is introduced. By this process coatings of small dimensions could be produced. Due to high processing speeds high cooling rates up to lO K/s are achieved by heat conduction into the substrate. This process results in fine microcrystalline structures of the deposit. Using NiCrBSi as coating material it will be shown how and to which extent different parameters influence structure and geometry of the coating. 2. MULTI-THIN-LAYER TECHNIQUE The multi-pass thin layer technique is in principle a powder feed process. Under an oblique angle a powder is blown by an inert gas stream into the laser beam. On their way to the surface the powder particles are partially heated. The surface itself is melted by the laser beam. So a good adherence is ensured between the molten surface and the impinging melting particles. This process can be repeated several times thus forming a coating by a multithinlayer technique see fig. 2. In principle the powder feed process is a well known " thick coating " process for conventional coatings like turbine blades dyes etc. /1/. In this however very small dimensions are desired which may be used for reasons of wear or corrosion resistance or for conductive or insolating layers in micro technics. In this work we investigated the influence of some processing parameters in order to achieve layers or traces of small geometries. 3. MULTIPLE THIN LAYER COATING OF NiCrBSi NiCrBSi had been used as a coating material to produce thin layers or traces. These alloys are hard and wear resistant materials which are usually applied by conventional powder spraying methods followed by arc- or flame-fusing of the sprayed layer

  13. Thin film coatings for space electrical power system applications

    NASA Technical Reports Server (NTRS)

    Gulino, Daniel A.

    1989-01-01

    This paper examines some of the ways in which thin film coatings can play a role in aerospace applications. Space systems discussed include photovoltaic and solar dynamic electric power generation systems, including applications in environmental protection, thermal energy storage, and radiator emittance enhancement. Potential applications of diamondlike films to both atmospheric and space based systems are examined. Also, potential uses of thin films of the recently discovered high-temperature superconductive materials are discussed.

  14. Thin film coatings for space electrical power system applications

    NASA Technical Reports Server (NTRS)

    Gulino, Daniel A.

    1988-01-01

    This paper examines some of the ways in which thin film coatings can play a role in aerospace applications. Space systems discussed include photovoltaic and solar dynamic electric power generation systems, including applications in environmental protection, thermal energy storage, and radiator emittance enhancement. Potential applications of diamondlike films to both atmospheric and space based systems are examined. Also, potential uses of thin films of the recently discovered high-temperature superconductive materials are discussed.

  15. Applications of thin carbon coatings and films in injection molding

    NASA Astrophysics Data System (ADS)

    Cabrera, Eusebio Duarte

    In this research, the technical feasibility of two novel applications of thin carbon coatings is demonstrated. The first application consists of using thin carbon coatings on molds for molding ultra-thin plastic parts (<0.5 mm thickness) with lower pressures by promoting wall slip. The second application consists of a new approach to provide electromagnetic interference (EMI) shielding for plastic parts using in mold coated nanoparticle thin films or nanopapers to create a conductive top layer. During this research, the technical feasibility of a new approach was proven which provides injection molding of ultra-thin parts at lower pressures, without the need of fast heating/fast cooling or other expensive mold modification. An in-house developed procedure by other members of our group, was employed for coating the mold surface using chemical vapor deposition (CVD) resulting in a graphene coating with carbide bonding to the mold surface. The coating resulted in a significant decrease of surface friction and consequently easiness of flow when compared to their uncoated counterparts. Thermoplastic polymers and their composites are a very attractive alternative but are hindered by the non-conductive nature of polymers. There are two general approaches used to date to achieve EMI shielding for plastic products. One is to spray a conductive metal coating onto the plastic surface forming a layer that must maintain its shielding effectiveness (SE), and its adhesion to the plastic throughout the expected life of the product. However, metal coatings add undesirable weight and tend to corrode over time. Furthermore, scratching the coating may create shielding failure; therefore, a protective topcoat may be required. The other approach is to use polymer composites filled with conductive fillers such as carbon black (CB), carbon nanofiber (CNF), and carbon nanotube (CNT). While conductive fillers may increase the electrical conductivity of polymer composites, the loading of

  16. Controlling the scattering properties of thin, particle-doped coatings

    NASA Astrophysics Data System (ADS)

    Rogers, William; Corbett, Madeleine; Manoharan, Vinothan

    2013-03-01

    Coatings and thin films of small particles suspended in a matrix possess optical properties that are important in several industries from cosmetics and paints to polymer composites. Many of the most interesting applications require coatings that produce several bulk effects simultaneously, but it is often difficult to rationally formulate materials with these desired optical properties. Here, we focus on the specific challenge of designing a thin colloidal film that maximizes both diffuse and total hemispherical transmission. We demonstrate that these bulk optical properties follow a simple scaling with two microscopic length scales: the scattering and transport mean free paths. Using these length scales and Mie scattering calculations, we generate basic design rules that relate scattering at the single particle level to the film's bulk optical properties. These ideas will be useful in the rational design of future optically active coatings.

  17. Magnetoelastic sensor for characterizing properties of thin-film/coatings

    NASA Technical Reports Server (NTRS)

    Bachas, Leonidas G. (Inventor); Barrett, Gary (Inventor); Grimes, Craig A. (Inventor); Kouzoudis, Dimitris (Inventor); Schmidt, Stefan (Inventor)

    2004-01-01

    An apparatus for determining elasticity characteristics of a thin-film layer. The apparatus comprises a sensor element having a base magnetostrictive element at least one surface of which is at least partially coated with the thin-film layer. The thin-film layer may be of a variety of materials (having a synthetic and/or bio-component) in a state or form capable of being deposited, manually or otherwise, on the base element surface, such as by way of eye-dropper, melting, dripping, brushing, sputtering, spraying, etching, evaporation, dip-coating, laminating, etc. Among suitable thin-film layers for the sensor element of the invention are fluent bio-substances, thin-film deposits used in manufacturing processes, polymeric coatings, paint, an adhesive, and so on. A receiver, preferably remotely located, is used to measure a plurality of values for magneto-elastic emission intensity of the sensor element in either characterization: (a) the measure of the plurality of values is used to identify a magneto-elastic resonant frequency value for the sensor element; and (b) the measure of the plurality of successive values is done at a preselected magneto-elastic frequency.

  18. Wear resistance of TiAlSiN thin coatings.

    PubMed

    Silva, F J G; Martinho, R P; Alexandre, R J D; Baptista, A P M

    2012-12-01

    In the last decades TiAIN coatings deposited by PVD techniques have been extensively investigated but, nowadays, their potential development for tribological applications is relatively low. However, new coatings are emerging based on them, trying to improve wear behavior. TiAlSiN thin coatings are now investigated, analyzing if Si introduction increases the wear resistance of PVD films. Attending to the application, several wear test configurations has been recently used by some researchers. In this work, TiAISiN thin coatings were produced by PVD Unbalanced Magnetron Sputtering technique and they were conveniently characterized using Scanning Electron Microscopy (SEM) provided with Energy Dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM), Electron Probe Micro-Analyzer (EPMA), Micro Hardness (MH) and Scratch Test Analysis. Properties as morphology, thickness, roughness, chemical composition and structure, hardness and film adhesion to the substrate were investigated. Concerning to wear characterization, two very different ways were chosen: micro-abrasion with ball-on-flat configuration and industrial non-standardized tests based on samples inserted in a feed channel of a selected plastic injection mould working with 30% (wt.) glass fiber reinforced polypropylene. TiAISiN coatings with a small amount of about 5% (wt.) Si showed a similar wear behavior when compared with TiAIN reported performances, denoting that Si addition does not improve the wear performance of the TiAIN coatings in these wear test conditions.

  19. Stress-warping relation in thin film coated wafers

    NASA Astrophysics Data System (ADS)

    Schicker, J.; Khan, W. A.; Arnold, T.; Hirschl, C.

    2017-02-01

    A misfit strain or stress in a thin layer on the surface of a wafer lets the composite disk warp. When the wafer is thin and large, the Stoney estimation of the film stress as function of the curvature yields large errors. We present a nonlinear analytical model that describes the relationship between warpage and film stress on an anisotropic wafer, and give evidence for its suitability for large thin wafers by a comparison to finite element results. Finally, we show the confidence limit of the Stoney estimation and the benefit by the nonlinear model. For thin coatings, it can be succesfully used even without knowledge of the film properties, which was the main advantage of the Stoney estimation.

  20. Durable silver thin film coating for diffraction gratings

    DOEpatents

    Wolfe, Jesse D.; Britten, Jerald A.; Komashko, Aleksey M.

    2006-05-30

    A durable silver film thin film coated non-planar optical element has been developed to replace Gold as a material for fabricating such devices. Such a coating and resultant optical element has an increased efficiency and is resistant to tarnishing, can be easily stripped and re-deposited without modifying underlying grating structure, improves the throughput and power loading of short pulse compressor designs for ultra-fast laser systems, and can be utilized in variety of optical and spectrophotometric systems, particularly high-end spectrometers that require maximized efficiency.

  1. Tantalum-based thin film coatings for wear resistant arthroprostheses.

    PubMed

    Balagna, C; Faga, M G; Spriano, S

    2011-10-01

    Cobalt-chromium-molybdenum alloys with high carbon content (HC-CoCrMo) are widely used as materials for arthroprosthesis, in particular in metal-on-metal (MoM) hip joints. In spite of their good wear and corrosion resistance, production of metallic wear particles and metal ion release will occur on a large time-scale. An enhancement of the metal ion level in the patient's blood and urine is often reported in clinical data. Hypersensitivity, inflammatory response and cell necrosis can occur as consequence. So implants on young patients and women on childbearing age are not so widespread. The aim of this research is the realization of a thin film coating in order to improve the biocompatibility of Co-based alloys and to reduce debris production, ion release and citotoxicity. The innovative process consists of a thermal treatment in molten salts, in order to obtain a tantalum enriched thin film coating. Tantalum is chosen because it is considered a biocompatible metal with high corrosion resistance and low ion release. Three HC-CoCrMo alloys, produced by different manufacturing processes, are tested as substrates. The coating is a thin film of TaC or it can be composed by a multilayer of two tantalum carbides and metallic tantalum, depending on the temperature of the treatment and on the carbon content of the substrate. The thin films as well the substrates are characterized from the structural, chemical and morphological point of view. Moreover mechanical behaviour of treated and untreated materials is analyzed by means of nanohardness, scratch and ball-on-disc wear tests. The coating increases the mechanical and tribological properties of HC-CoCrMo.

  2. Antimicrobial nanospheres thin coatings prepared by advanced pulsed laser technique

    PubMed Central

    Holban, Alina Maria; Grumezescu, Valentina; Vasile, Bogdan Ştefan; Truşcă, Roxana; Cristescu, Rodica; Socol, Gabriel; Iordache, Florin

    2014-01-01

    Summary We report on the fabrication of thin coatings based on polylactic acid-chitosan-magnetite-eugenol (PLA-CS-Fe3O4@EUG) nanospheres by matrix assisted pulsed laser evaporation (MAPLE). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) investigation proved that the homogenous Fe3O4@EUG nanoparticles have an average diameter of about 7 nm, while the PLA-CS-Fe3O4@EUG nanospheres diameter sizes range between 20 and 80 nm. These MAPLE-deposited coatings acted as bioactive nanosystems and exhibited a great antimicrobial effect by impairing the adherence and biofilm formation of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) bacteria strains. Moreover, the obtained nano-coatings showed a good biocompatibility and facilitated the normal development of human endothelial cells. These nanosystems may be used as efficient alternatives in treating and preventing bacterial infections. PMID:24991524

  3. Antimicrobial nanospheres thin coatings prepared by advanced pulsed laser technique.

    PubMed

    Holban, Alina Maria; Grumezescu, Valentina; Grumezescu, Alexandru Mihai; Vasile, Bogdan Ştefan; Truşcă, Roxana; Cristescu, Rodica; Socol, Gabriel; Iordache, Florin

    2014-01-01

    We report on the fabrication of thin coatings based on polylactic acid-chitosan-magnetite-eugenol (PLA-CS-Fe3O4@EUG) nanospheres by matrix assisted pulsed laser evaporation (MAPLE). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) investigation proved that the homogenous Fe3O4@EUG nanoparticles have an average diameter of about 7 nm, while the PLA-CS-Fe3O4@EUG nanospheres diameter sizes range between 20 and 80 nm. These MAPLE-deposited coatings acted as bioactive nanosystems and exhibited a great antimicrobial effect by impairing the adherence and biofilm formation of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) bacteria strains. Moreover, the obtained nano-coatings showed a good biocompatibility and facilitated the normal development of human endothelial cells. These nanosystems may be used as efficient alternatives in treating and preventing bacterial infections.

  4. Examination of the influence of coatings on thin superalloy sections

    NASA Technical Reports Server (NTRS)

    Kaufman, M.

    1972-01-01

    The effects of two coatings, Codep B-1 and CoCrAlY, with and without simulated engine exposures at 982 C (1800 F) and 1093 C (2000 F), were evaluated on cast sections of Rene 80. Section thicknesses were from 0.075 cm (0.030 inch) to 0.15 cm (0.060 inch). Tensile and stress rupture properties, mechanical fatigue, thermal fatigue, ballistic impact and hot corrosion at R. T. and elevated temperatures were investigated. Thin sections generally had poorer tensile strengths and lower stress rupture lives than standard 1/4 inch round gage bars. The coatings, as-applied, had little effect on tensile strengths, rupture lives and mechanical fatigue and they increased thermal fatigue, ballistic impact and hot corrosion resistance. By providing considerable exposure protection to the Rene 80, the coatings improved all properties compared to exposed bare specimens.

  5. Antifouling coating of cellulose acetate thin films with polysaccharide multilayers.

    PubMed

    Mohan, Tamilselvan; Kargl, Rupert; Tradt, Karin Eva; Kulterer, Martin R; Braćić, Matej; Hribernik, Silvo; Stana-Kleinschek, Karin; Ribitsch, Volker

    2015-02-13

    In this investigation, partially deacetylated cellulose acetate (DCA) thin films were prepared and modified with hydrophilic polysaccharides with the layer-by-layer (LbL) technique. As polysaccharides, chitosan (CHI) and carboxymethyl cellulose (CMC) were used. DCA thin films were manufactured by exposing spin coated cellulose acetate to potassium hydroxide solutions for various times. The deacetylation process was monitored by attenuated total reflectance-infrared spectroscopy, film thickness and static water contact angle measurements. A maximum of three bilayers was created from the alternating deposition of CHI and CMC on the DCA films under two different conditions namely constant ionic strengths and varying pH values of the CMC solutions. Precoatings of CMC at pH 2 were used as a base layer. The sequential deposition of CMC and CHI was investigated with a quartz crystal microbalance with dissipation, film thickness, static water contact angle and atomic force microscopy (AFM) measurements. The versatility and applicability of the developed functional coatings was shown by removing the multilayers by rinsing with mixtures containing HCl/NaCl. The developed LbL coatings are used for studying the fouling behavior of bovine serum albumin (BSA).

  6. Suppression of vacuum breakdown using thin film coatings

    SciTech Connect

    Fleddermann, C.B.; Mayberry, C.S.; Wroblewski, B.; Schamiloglu, E.

    1993-12-01

    The use of thin film coatings for increasing the breakdown voltage in a parallel-plane high-voltage gap has been investigated. Both metallic and ceramic thin films were deposited at varying thicknesses and deposition conditions on a screen cathode using ion-beam sputtering. Improvements in breakdown voltage were observed for nearly any type of deposited film, with significant variations in breakdown voltage depending on film thickness and oxygen and partial pressure during ceramic film deposition. For 500 nm thick metallic or oxide films, breakdown voltage was nearly doubled compared to the bare stainless steel screen, which is attributed to the burying of surface imperfections on the cathode. For 200 nm thick films, the covering of imperfections is less effective; however, high breakdown voltages can still be obtained by choosing an appropriate oxygen partial pressure during film deposition. Electric fields as high as 60 kV/mm were sustained across a 1 mm gap for 10 {mu}sec pulses; lesser fields could be sustained for as long as 10 ms. These coatings allowed for the successful study of a planar liquid metal ion source.

  7. Ultra-thin Polyethylene glycol Coatings for Stem Cell Culture

    NASA Astrophysics Data System (ADS)

    Schmitt, Samantha K.

    Human mesenchymal stem cells (hMSCs) are a widely accessible and a clinically relevant cell type that are having a transformative impact on regenerative medicine. However, current clinical expansion methods can lead to selective changes in hMSC phenotype resulting from relatively undefined cell culture surfaces. Chemically defined synthetic surfaces can aid in understanding stem cell behavior. In particular we have developed chemically defined ultra-thin coatings that are stable over timeframes relevant to differentiation of hMSCs (several weeks). The approach employs synthesis of a copolymer with distinct chemistry in solution before application to a substrate. This provides wide compositional flexibility and allows for characterization of the orthogonal crosslinking and peptide binding groups. Characterization is done in solution by proton NMR and after crosslinking by X-ray photoelectron spectroscopy (XPS). The solubility of the copolymer in ethanol and low temperature crosslinking, expands its applicability to plastic substrates, in addition to silicon, glass, and gold. Cell adhesive peptides, namely Arg-Gly-Asp (RGD) fragments, are coupled to coating via different chemistries resulting in the urethane, amide or the thioester polymer-peptide bonds. Development of azlactone-based chemistry allowed for coupling in water at low peptide concentrations and resulted in either an amide or thioester bonds, depending on reactants. Characterization of the peptide functionalized coating by XPS, infrared spectroscopy and cell culture assays, showed that the amide linkages can present peptides for multiple weeks, while shorter-term presentation of a few days is possible using the more labile thioester bond. Regardless, coatings promoted initial adhesion and spreading of hMSCs in a peptide density dependent manner. These coatings address the following challenges in chemically defined cell culture simultaneously: (i) substrate adaptability, (ii) scalability over large areas

  8. Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection

    DTIC Science & Technology

    2009-02-01

    Carbon Nanotube Functionalization /Doping Polyvinylpyrrolidone (PVP) A) p-Doping C) Polymer Wrapping Model B) n-Doping Polyethyleneimine ( PEI ) SWCNT Paint...fluorine-containing) groups functions as the barrier layer Multilayer Smart Carbon Nanotube Coating Insoluble polymer layer top coating -PMMA Substrate...Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection Zafar Iqbal Department of Chemistry and Environmental Science New

  9. Electrochromic NiO thin films prepared by spin coating

    NASA Astrophysics Data System (ADS)

    Özütok, F.; Demiri, S.; Özbek, E.

    2017-02-01

    Recently, smart windows are very important because they are often being used in smart buildings and car glasses (windows). At this point, producing effective electrochromic materials is so necessary. In this study, we produced NiO thin films by using spin coating technique on In-doped SnO2 (ITO) substrate. Nickel proportions of these nickel oxide (NiO) films are 3, 5 and 7 %. Nickel acetate tetrahydrate is the initial solution and solvents are ethylene gl ycol and n-hexzane. Structural properties and surface images are investigated by using x-ray diffactometer (XRD) and scanning electron microscope (SEM) device, respectively. In addition, electrochemical behavior is investigated by cyclic voltammetry. A correlation between surface morphology and electrochromic performance was observed as well.

  10. 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.

  11. Colloidal spray method for low cost thin coating deposition

    DOEpatents

    Pham, Ai-Quoc; Glass, Robert S.; Lee, Tae H.

    2002-01-01

    A dense or porous coating of material is deposited onto a substrate by forcing a colloidal suspension through an ultrasonic nebulizer and spraying a fine mist of particles in a carrier medium onto a sufficiently heated substrate. The spraying rate is essentially matched to the evaporation rate of the carrier liquid from the substrate to produce a coating that is uniformly distributed over the surface of the substrate. Following deposition to a sufficient coating thickness, a single sintering step may be used to produce a dense ceramic coating. Using this method, coatings ranging in thickness from about one to several hundred microns can be obtained. By using a plurality of compounds in the colloidal suspension, coatings of mixed composition can be obtained. By using a plurality of solutions and separate pumps and a single or multiple ultrasonic nebulizer(s), and varying the individual pumping rates and/or the concentrations of the solutions, a coating of mixed and discontinuously graded (e.g., stepped) or continuously graded layers may be obtained. This method is particularly useful for depositing ceramic coatings. Dense ceramic coating materials on porous substrates are useful in providing improved electrode performance in devices such as high power density solid oxide fuel cells. Dense ceramic coatings obtained by the invention are also useful for gas turbine blade coatings, sensors, steam electrolyzers, etc. The invention has general use in preparation of systems requiring durable and chemically resistant coatings, or coatings having other specific chemical or physical properties.

  12. Colloidal spray method for low cost thin coating deposition

    DOEpatents

    Pham, Ai-Quoc; Glass, Robert S.; Lee, Tae H.

    2005-01-25

    A dense or porous coating of material is deposited onto a substrate by forcing a colloidal suspension through an ultrasonic nebulizer and spraying a fine mist of particles in a carrier medium onto a sufficiently heated substrate. The spraying rate is essentially matched to the evaporation rate of the carrier liquid from the substrate to produce a coating that is uniformly distributed over the surface of the substrate. Following deposition to a sufficient coating thickness, a single sintering step may be used to produce a dense ceramic coating. Using this method, coatings ranging in thickness from about one to several hundred microns can be obtained. By using a plurality of compounds in the colloidal suspension, coatings of mixed composition can be obtained. By using a plurality of solutions and separate pumps and a single or multiple ultrasonic nebulizer(s), and varying the individual pumping rates and/or the concentrations of the solutions, a coating of mixed and discontinuously graded (e.g., stepped) or continuously graded layers may be obtained. This method is particularly useful for depositing ceramic coatings. Dense ceramic coating materials on porous substrates are useful in providing improved electrode performance in devices such as high power density solid oxide fuel cells. Dense ceramic coatings obtained by the invention are also useful for gas turbine blade coatings, sensors, steam electrolyzers, etc. The invention has general use in preparation of systems requiring durable and chemically resistant coatings, or coatings having other specific chemical or physical properties.

  13. Ultra-thin flexible polyimide neural probe embedded in a dissolvable maltose-coated microneedle

    NASA Astrophysics Data System (ADS)

    Xiang, Zhuolin; Yen, Shih-Cheng; Xue, Ning; Sun, Tao; Mong Tsang, Wei; Zhang, Songsong; Liao, Lun-De; Thakor, Nitish V.; Lee, Chengkuo

    2014-06-01

    The ultra-thin flexible polyimide neural probe can reduce the glial sheath growth on the probe body while its flexibility can minimize the micromotion between the probe and brain tissue. To provide sufficient stiffness for penetration purposes, we developed a drawing lithography technology for uniform maltose coating to make the maltose-coated polyimide neural probe become a stiff microneedle. The coating thicknesses under different temperature and the corresponding stiffness are studied. It has been proven that the coated maltose is dissolved by body fluids after implantation for a few seconds. Moreover, carbon nanotubes are coated on the neural probe recording electrodes to improve the charge delivery ability and reduce the impedance. Last but not least, the feasibility and recording characteristic of this ultra-thin polyimide neural probe embedded in a maltose-coated microneedle are further demonstrated by in vivo tests.

  14. Technologies for Nondestructive Evaluation of Surfaces and Thin Coatings

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The effort included in this project included several related activities encompassing basic understanding, technological development, customer identification and commercial transfer of several methodologies for nondestructive evaluation of surfaces and thin surface coatings. Consistent with the academic environment, students were involved in the effort working with established investigators to further their training, provide a nucleus of experienced practitioners in the new technologies during their industrial introduction, and utilize their talents for project goals. As will be seen in various portions of the report, some of the effort has led to commercialization. This process has spawned other efforts related to this project which are supported from outside sources. These activities are occupying the efforts of some of the people who were previously supported within this grant and its predecessors. The most advanced of the supported technologies is thermography, for which the previous joint efforts of the investigators and NASA researchers have developed several techniques for extending the utility of straight thermographic inspection by producing methods of interpretation and analysis accessible to automatic image processing with computer data analysis. The effort reported for this technology has been to introduce the techniques to new user communities, who are then be able to add to the effective uses of existing products with only slight development work. In a related development, analysis of a thermal measurement situation in past efforts led to a new insight into the behavior of simple temperature probes. This insight, previously reported to the narrow community in which the particular measurement was made, was reported to the community of generic temperature measurement experts this year. In addition to the propagation of mature thermographic techniques, the development of a thermoelastic imaging system has been an important related development. Part of the

  15. A model for drying control cosolvent selection for spin-coating uniformity: the thin film limit.

    PubMed

    Birnie, Dunbar P

    2013-07-23

    Striation defects in spin-coated thin films are a result of unfavorable capillary forces that develop due to the physical processes commonly involved in the spin-coating technique. Solvent evaporation during spinning causes slight compositional changes in the coating during drying, and these changes lead to instability in the surface tension, which causes lateral motions of the drying fluid up to the point where it gels and freezes in the thickness variations. In an earlier publication, we looked at the case where evaporation happens fast enough that the compositional depletion is mostly a surface effect. In terms of the mass transport rate competition within the coating solution, that work covered the thick film limit of this instability problem. However, in many cases, the coatings are thin enough or diffusion of solvent within the coating is fast enough to require a different solvent mixing strategy, which is developed here. A simple perturbation analysis of surface roughness is developed, and evaporation is allowed in the thin film limit. The perturbation analysis allows for a simple rubric to be laid out for cosolvent additions that can reduce the Marangoni effect during the later stages of coating deposition and drying when the thin film limit applies.

  16. Extracellular matrix proteins as temporary coating for thin-film neural implants

    NASA Astrophysics Data System (ADS)

    Ceyssens, Frederik; Deprez, Marjolijn; Turner, Neill; Kil, Dries; van Kuyck, Kris; Welkenhuysen, Marleen; Nuttin, Bart; Badylak, Stephen; Puers, Robert

    2017-02-01

    Objective. This study investigates the suitability of a thin sheet of extracellular matrix (ECM) proteins as a resorbable coating for temporarily reinforcing fragile or ultra-low stiffness thin-film neural implants to be placed on the brain, i.e. microelectrocorticographic (µECOG) implants. Approach. Thin-film polyimide-based electrode arrays were fabricated using lithographic methods. ECM was harvested from porcine tissue by a decellularization method and coated around the arrays. Mechanical tests and an in vivo experiment on rats were conducted, followed by a histological tissue study combined with a statistical equivalence test (confidence interval approach, 0.05 significance level) to compare the test group with an uncoated control group. Main results. After 3 months, no significant damage was found based on GFAP and NeuN staining of the relevant brain areas. Significance. The study shows that ECM sheets are a suitable temporary coating for thin µECOG neural implants.

  17. Undercutting of defects in thin film protective coatings on polymer surfaces exposed to atomic oxygen

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Mihelcic, Judith A.

    1989-01-01

    Protection for polymeric surfaces is needed to make them durable in the low Earth orbital environment, where oxidation by atomic oxygen is the predominant failure mechanism. Thin film coatings of oxides such as silicon dioxide are viable candidates to provide this protection, but concern has been voiced over the ability of these coatings to protect when defects are present in the coating due to surface anomalies occurring during the deposition process, handling, or micrometeoroid and debris bombardment in low Earth orbit. When a defected coating protecting a polymer substrate is exposed to atomic oxygen, the defect provides a pathway to the underlying polymer allowing oxidation and subsequent undercutting to occur. Defect undercutting was studied for sputter deposited coatings of silicon dioxide on polyimide Kapton. Preliminary results indicate that undercutting may be limited as long as the coating remains intact with the substrate. Therefore, coatings may not need to be defect free to give protection to the underlying surface.

  18. Undercutting of defects in thin film protective coatings on polymer surfaces exposed to atomic oxygen

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Mihelcic, Judith A.

    1989-01-01

    Protection for polymeric surfaces is needed to make them durable in the low earth orbital environment. Thin film coatings of oxides such as SiO2 are viable candidates to provide this protection, but concern has been voiced over the ability of these coatings to protect when defects are present in the coating due to surface anomalies. When a defected coating protecting a polymer substrate is exposed to atomic oxygen, the defect provides a pathway to the underlying polymer allowing oxidation and subsequent undercutting to occur. Defect undercutting was studied for sputter deposited coatings of SiO2 on polyimide Kapton. Preliminary results indicate that undercutting may be limited as long as the coating remains intact with the substrate. Therefore, coatings may not need to be defect free to give protection to the underlying surface.

  19. Thin coatings for protecting titanium aluminides in high-temperature oxidizing environments

    NASA Technical Reports Server (NTRS)

    Wiedemann, K. E.; Taylor, P. J.; Clark, R. K.; Wallace, T. A.

    1991-01-01

    Titanium aluminides have high specific strengths at high temperatures but are susceptible to environmental attack. Their use in many aerospace applications would require that they be protected with coatings that, for structural efficiency, must be thin. It is conceivable that acceptable coatings might be found in several oxide systems, and consequently, oxide coatings of many compositions were prepared from sol-gels for study. Response-surface methodology was used to refine coating compositions and factorial experiments were used to develop coating strategies. Oxygen permeability diagrams of two-layer coatings for several oxide systems, an analysis of multiple-layer coatings on rough and polished surfaces, and modeling of the oxidation weight gain are presented.

  20. Non-stick syringe needles: Beneficial effects of thin film metallic glass coating

    PubMed Central

    Chu, Jinn P.; Yu, Chia-Chi; Tanatsugu, Yusuke; Yasuzawa, Mikito; Shen, Yu-Lin

    2016-01-01

    This paper reports on the use of Zr-based (Zr53Cu33Al9Ta5) thin film metallic glass (TFMG) for the coating of syringe needles and compares the results with those obtained using titanium nitride and pure titanium coatings. TFMG coatings were shown to reduce insertion forces by ∼66% and retraction forces by ∼72%, when tested using polyurethane rubber block. The benefits of TFMG-coated needles were also observed when tested using muscle tissue from pigs. In nano-scratch tests, the TFMG coatings achieved a coefficient of friction (COF) of just ∼0.05, which is about one order of magnitude lower than those of other coatings. Finite-element modeling also indicates a significant reduction in injection and retraction forces. The COF can be attributed to the absence of grain boundaries in the TFMG coating as well as a smooth surface morphology and low surface free energy. PMID:27573062

  1. Thin-film silica sol-gel coatings for neural microelectrodes.

    PubMed

    Pierce, Andrew L; Sommakia, Salah; Rickus, Jenna L; Otto, Kevin J

    2009-05-30

    The reactive tissue response of the brain to chronically implanted materials remains a formidable obstacle to stable recording from implanted microelectrodes. One approach to mitigate this response is to apply a bioactive coating in the form of an ultra-porous silica sol-gel, which can be engineered to improve biocompatibility and to enable local drug delivery. The first step in establishing the feasibility of such a coating is to investigate the effects of the coating on electrode properties. In this paper, we describe a method to apply a thin-film silica sol-gel coating to silicon-based microelectrodes, and discuss the resultant changes in the electrode properties. Fluorescently labeled coatings were used to confirm coating adherence to the electrode. Cyclic voltammetry and impedance spectroscopy were used to evaluate electrical property changes. The silica sol-gel was found to successfully adhere to the electrodes as a thin coating. The voltammograms revealed a slight increase in charge carrying capacity of the electrodes following coating. Impedance spectrograms showed a mild increase in impedance at high frequencies but a more pronounced decrease in impedance at mid to low frequencies. These results demonstrate the feasibility of applying silica sol-gel coatings to silicon-based microelectrodes and are encouraging for the continued investigation of their use in mitigating the reactive tissue response.

  2. Thin film thermoelectric devices as thermal control coatings: A study

    NASA Technical Reports Server (NTRS)

    Clemons, J. M.; Krupnick, A. C.

    1973-01-01

    Peltier effect, Thomson effect, and Seeback effect are utilized in design of thermal control coating that serves as versatile means for controlling heat absorbed and radiated by surface. Coatings may be useful in extreme temperature environment enclosures or as heat shields.

  3. SnS thin films deposited by chemical bath deposition, dip coating and SILAR techniques

    NASA Astrophysics Data System (ADS)

    Chaki, Sunil H.; Chaudhary, Mahesh D.; Deshpande, M. P.

    2016-05-01

    The SnS thin films were synthesized by chemical bath deposition (CBD), dip coating and successive ionic layer adsorption and reaction (SILAR) techniques. In them, the CBD thin films were deposited at two temperatures: ambient and 70 °C. The energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and optical spectroscopy techniques were used to characterize the thin films. The electrical transport properties studies on the as-deposited thin films were done by measuring the I-V characteristics, DC electrical resistivity variation with temperature and the room temperature Hall effect. The obtained results are deliberated in this paper.

  4. Functionalized antibiofilm thin coatings based on PLA-PVA microspheres loaded with usnic acid natural compounds fabricated by MAPLE

    NASA Astrophysics Data System (ADS)

    Grumezescu, Valentina; Socol, Gabriel; Grumezescu, Alexandru Mihai; Holban, Alina Maria; Ficai, Anton; Truşcǎ, Roxana; Bleotu, Coralia; Balaure, Paul Cǎtǎlin; Cristescu, Rodica; Chifiriuc, Mariana Carmen

    2014-05-01

    We report the fabrication of thin coatings of PLA-PVA microspheres loaded with usnic acid by matrix assisted pulsed laser evaporation (MAPLE) onto Ti substrate. The obtained coatings have been physico-chemically characterized by scanning electron microscopy (SEM) and infrared microscopy (IRM). In vitro biological assays have been performed in order to evaluate the influence of fabricated microsphere thin coatings on the Staphylococcus aureus biofilm development as well as their biocompatibility. SEM micrographs have revealed a uniform morphology of thin coatings, while IRM investigations have proved both the homogeneity and functional groups integrity of prepared thin coatings. The obtained microsphere-based thin coatings have proved to be efficient vehicles for usnic acid natural compound with antibiofilm activity, as demonstrated by the inhibitory activity on S. aureus mature biofilm development, opening new perspectives for the prevention and therapy associated to biofilm related infections.

  5. Metallurgical coatings and thin films; Proceedings of the International Conference, 18th, San Diego, CA, Apr. 22-26, 1991. Vols. 1 & 2

    NASA Technical Reports Server (NTRS)

    Mcguire, Gary E. (Editor); Mcintyre, Dale C. (Editor); Hofmann, Siegfried (Editor)

    1991-01-01

    A conference on metallurgical coatings and thin films produced papers in the areas of coatings for use at high temperatures; hard coatings and deposition technologies; diamonds and related materials; tribological coatings/surface modifications; thin films for microelectronics and high temperature superconductors; optical coatings, film characterization, magneto-optics, and guided waves; and methods for characterizing films and modified surfaces.

  6. An investigation of material properties and tribological performance of magnetron sputtered thin film coatings

    NASA Astrophysics Data System (ADS)

    Singh, Harpal

    This dissertation is divided into two categories based upon lubrication functionality and its application. The categories are: Dry film lubrication and Fluid film lubrication with thin film coatings. Thin film coatings examined in this work were deposited using closed field unbalanced magnetron sputtering and RF-DC coupled magnetron sputtering systems. In Dry/Solid film lubrication, the mechanical, structural and tribological properties of two Molybdenum disulphide (MoS2) based coatings are examined and evaluated. Among the two coatings, one coating is doped with Ti (Ti-MoS2) and the other is a combination of metal, lubricant and oxide (Sb2O3/Au - MoS2). These coatings are known to provide low friction in vacuum environments. The goal of this work was to evaluate friction and wear performance of MoS2 doped coatings in unidirectional and reciprocating sliding contact under different environmental conditions. Sliding contact results showed friction and wear dependence on temperature and humidity. The formation and removal of transfer films and the recrystallization and reorientation of basal layers on the steel counterface was observed as the mechanism for low friction. Structural analysis revealed a relationship between the microstructural properties and tribological performance. It was also observed that the addition of dopants (Ti, Au, Sb 2O3) improved the mechanical properties as compared to pure MoS2 coatings. Further, the rolling contact performance of the coatings was measured on a five ball on rod tribometer and a Thrust bearing tribometer under vacuum and air environments. The rolling contact experiments indicated that life of the rolling components depend on the amount of material present between the contacts. Fluid film lubrication with thin film coatings investigates the possibilities to improve the performance and durability of tribological components when oils and thin films are synergistically coupled. In this work, the ability of a Diamond Like Carbon

  7. Plasma treatment of thin film coated with graphene flakes for the reduction of sheet resistance.

    PubMed

    Kim, Sung Hee; Oh, Jong Sik; Kim, Kyong Nam; Seo, Jin Seok; Jeon, Min Hwan; Yang, Kyung Chae; Yeom, Geun Young

    2013-12-01

    We investigated the effects of plasma treatment on the sheet resistance of thin films spray-coated with graphene flakes on polyethylene terephthalate (PET) substrates. Thin films coated with graphene flakes show high sheet resistance due to defects within graphene edges, domains, and residual oxygen content. Cl2 plasma treatment led to decreased sheet resistance when treatment time was increased, but when thin films were treated for too long the sheet resistance increased again. Optimum treatment time was related to film thickness. The reduction of sheet resistance may be explained by the donation of holes due to forming pi-type covalent bonds of Cl with carbon atoms on graphene surfaces, or by C--Cl bonding at the sites of graphene defects. However, due to radiation damage caused by plasma treatment, sheet resistance increased with increased treatment time. We found that the sheet resistance of PET film coated with graphene flakes could be decreased by 50% under optimum conditions.

  8. Silver Nanoparticle-Embedded Thin Silica-Coated Graphene Oxide as an SERS Substrate

    PubMed Central

    Pham, Xuan-Hung; Hahm, Eunil; Kim, Hyung-Mo; Shim, Seongbo; Kim, Tae Han; Jeong, Dae Hong; Lee, Yoon-Sik; Jun, Bong-Hyun

    2016-01-01

    A hybrid of Ag nanoparticle (NP)-embedded thin silica-coated graphene oxide (GO@SiO2@Ag NPs) was prepared as a surface-enhanced Raman scattering (SERS) substrate. A 6 nm layer of silica was successfully coated on the surface of GO by the physical adsorption of sodium silicate, followed by the hydrolysis of 3-mercaptopropyl trimethoxysilane. Ag NPs were introduced onto the thin silica-coated graphene oxide by the reduction of Ag+ to prepare GO@SiO2@Ag NPs. The GO@SiO2@Ag NPs exhibited a 1.8-fold enhanced Raman signal compared to GO without a silica coating. The GO@SiO2@Ag NPs showed a detection limit of 4-mercaptobenzoic acid (4-MBA) at 0.74 μM. PMID:28335304

  9. Growth of textured thin Au coatings on iron oxide nanoparticles with near infrared absorbance

    PubMed Central

    Ma, L L; Borwankar, A U; Willsey, B W; Yoon, K Y; Tam, J O; Sokolov, K V; Feldman, M D; Milner, T E; Johnston, K P

    2013-01-01

    A homologous series of Au-coated iron oxide nanoparticles, with hydrodynamic diameters smaller than 60 nm was synthesized with very low Auto-iron mass ratios as low as 0.15. The hydrodynamic diameter was determined by dynamic light scattering and the composition by atomic absorption spectroscopy and energy dispersive x-ray spectroscopy (EDS). Unusually low Au precursor supersaturation levels were utilized to nucleate and grow Au coatings on iron oxide relative to formation of pure Au nanoparticles. This approach produced unusually thin coatings, by lowering autocatalytic growth of Au on Au, as shown by transmission electron microscopy (TEM). Nearly all of the nanoparticles were attracted by a magnet indicating a minimal amount of pure Au particles The coatings were sufficiently thin to shift the surface plasmon resonance (SPR) to the near infrared (NIR), with large extinction coefficients., despite the small particle hydrodynamic diameters, observed from dynamic light scattering to be less than 60 nm. PMID:23238021

  10. Deformation of rectangular thin glass plate coated with magnetostrictive material

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoli; Yao, Youwei; Liu, Tianchen; Liu, Chian; Ulmer, M. P.; Cao, Jian

    2016-08-01

    As magnetic smart materials (MSMs), magnetostrictive materials have great potential to be selected as coating materials for lightweight x-ray telescope mirrors due to their capability to tune the mirror profile to the desired shape under a magnetic field. To realize this potential, it is necessary to study the deformation of the mirror substrate with the MSM coating subjected to a localized magnetic field. In this paper, an analytical model is developed to calculate the deformation of rectangular coated samples locally affected by magnetostrictive strains driven by an external magnetic field. As a specific case to validate the model, a square glass sample coated with MSMs is prepared, and its deformation is measured in a designed experimental setup by applying a magnetic field. The measured deformation of the sample is compared with the results calculated from the analytical model. The comparison results demonstrate that the analytical model is effective in calculating the deformation of a coated sample with the localized mismatch strains between the film and the substrate. In the experiments, different shape patterns of surface profile changes are achieved by varying the direction of the magnetic field. The analytical model and the experimental method proposed in this paper can be utilized to further guide the application of magnetostrictive coating to deformable lightweight x-ray mirrors in the future.

  11. Synthesis and characterization of monodisperse ultra-thin silica-coated magnetic nanoparticles.

    PubMed

    Zhang, Ming; Cushing, Brian L; O'Connor, Charles J

    2008-02-27

    A systematic study of the formation of silica-coated magnetite particles via a modified reverse microemulsion approach was investigated by using transmission electron microscopy (TEM), x-ray diffraction (XRD) and a superconducting quantum interference device (SQUID). The results show that the surfactant Igepal CO-520 played an important role in the reaction system, and the thickness of the silica shell could be controlled by the concentration of the reaction agents. The developed ultra-thin silica-coated magnetic particles with a ∼2 nm thin silica shell have a high saturated magnetization around 15 emu g(-1).

  12. Synthesis and characterization of monodisperse ultra-thin silica-coated magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Ming; Cushing, Brian L.; O'Connor, Charles J.

    2008-02-01

    A systematic study of the formation of silica-coated magnetite particles via a modified reverse microemulsion approach was investigated by using transmission electron microscopy (TEM), x-ray diffraction (XRD) and a superconducting quantum interference device (SQUID). The results show that the surfactant Igepal CO-520 played an important role in the reaction system, and the thickness of the silica shell could be controlled by the concentration of the reaction agents. The developed ultra-thin silica-coated magnetic particles with a ~2 nm thin silica shell have a high saturated magnetization around 15 emu g-1.

  13. Thin boron phosphide coating as a corrosion-resistant layer

    DOEpatents

    Not Available

    1982-08-25

    A surface prone to corrosion in corrosive environments is rendered anticorrosive by CVD growing a thin continuous film, e.g., having no detectable pinholes, thereon, of boron phosphide. In one embodiment, the film is semiconductive. In another aspect, the invention is an improved photoanode, and/or photoelectrochemical cell with a photoanode having a thin film of boron phosphide thereon rendering it anticorrosive, and providing it with unexpectedly improved photoresponsive properties.

  14. Recent advances in short-wavelength AR coatings for thinned CCDs

    NASA Astrophysics Data System (ADS)

    Blouke, Morley; Nelson, Michael D.; Serra, M.; Knoesen, Andre; Higgins, B.; Delamere, W. Alan; Womack, Gary L.; Flores, James S.; Duncan, T. M.; Reed, R.

    1992-08-01

    This paper discusses the development of two materials as AR coatings for thinned backilluminated charge-coupled devices. The first material is the heavy metal oxide Ta205 deposited as a spin on layer using sol-gel technology. The second material is Si3N4. Both these films have the high index of refraction and low absorption coefficients needed to produce good AR coatings in the near UV down to 300 nm. The goal of the program was to produce a coating which would yield devices with quantum efficiencies of greater than 50 at 300 nm. Both these materials satisfy this goal. Data on test devices will be reported. . 1.

  15. Fabricating thin-film photovoltaic devices using ultra-sonic spray-coating (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Lidzey, David G.

    2015-10-01

    The scale-up of thin-film electronic devices requires a manufacture tool set that is capable of fabricating thin films at high speed over large areas. One such technique capable of such a task is ultra-sonic spray coating. Here, a target solution is fed onto a vibrating tip that breaks the solution up into very fine droplets, with such droplets being carried to a surface by a gas stream. Such ultra-sonic coating processes are already widely used in Electronics, Medical and Displays industries to create films having excellent smoothness and homogeneity. In this talk, I describe the use of ultra-sonic spray-coating to deposit a range of materials for thin-film optoelectronics. As our spray-coating system operates in air, it was first necessary to explore the relative sensitivity of various conjugated polymer / fullerene blends to an air-based process route. It is found that carbazole based co-polymers are particularly stable, and can be processed in air (by spin-coating) into organic photovoltaic devices (OPV) without any apparent loss in device efficiency. I then show that spray-coating can be used to deposit a range of semiconductor materials into smooth, thin-films, including PEDOT:PSS, MoOx (from a precursor) and a series of polymer:fullerene blends. Using such a technique, we are able to scale up an array of devices having an area of 7 cm2, and using a PBDTTT-EFT:PC70BM blend, obtain OPVs having a power conversion efficiency (PCE) of 8.7%. I then discuss spray-coating as a method to fabricate photovoltaic devices based on CH3NH3PbI(3-x)Clx perovskite films. Here, by optimization of deposition parameters, devices are created having a PCE of 11.1%.

  16. Laser deposition of SmCo thin film and coating on different substrates

    NASA Astrophysics Data System (ADS)

    Allocca, L.; Bonavolontà, C.; Giardini, A.; Lopizzo, T.; Morone, A.; Valentino, M.; Verrastro, M. F.; Viggiano, V.

    2008-10-01

    Thin films and coatings of permanent magnetic materials are very important for different electronic and micromechanical applications. This paper deals with the fabrication, using pulsed laser deposition (PLD) technique, of good quality magnetic SmCo thin films on polycarbonate, steel, silicon and amorphous quartz substrates, for low cost electronic applications like radio frequency identification (RFID) antennas and electromechanical devices for fuel feeding control in the automotive. X-ray fluorescence and magnetic scanning measurements using giant magneto-resistive (GMR) sensors have been performed to study the functional magnetic properties of the deposited thin films.

  17. Experimental observation of rainbow scattering by a coated cylinder: twin primary rainbows and thin-film interference.

    PubMed

    Adler, C L; Lock, J A; Nash, J K; Saunders, K W

    2001-03-20

    We experimentally examine the primary rainbow created by the illumination of a coated cylinder. We present a simple technique for varying the coating thickness over a wide range of values, and we see evidence for two different scattering regimes. In one, where the coating thickness is large, twin rainbows are produced. In the second, where the coating is thin enough to act as a thin film, a single rainbow is produced whose intensity varies periodically as the coating thickness varies. We find good agreement with previous theoretical predictions.

  18. Preparation and antimicrobial assay of ceramic brackets coated with TiO2 thin films

    PubMed Central

    Cao, Shuai; Wang, Ye; Cao, Lin; Wang, Yu; Lin, Bingpeng; Lan, Wei

    2016-01-01

    Objective Different methods have been utilized to prevent enamel demineralization and other complications during orthodontic treatment. However, none of these methods can offer long-lasting and effective prevention of orthodontic complications or interventions after complications occur. Considering the photocatalytic effect of TiO2 on organic compounds, we hoped to synthesize a novel bracket with a TiO2 thin film to develop a photocatalytic antimicrobial effect. Methods The sol-gel dip coating method was used to prepare TiO2 thin films on ceramic bracket surfaces. Twenty groups of samples were composed according to the experimental parameters. Crystalline structure and surface morphology were characterized by X-ray diffraction and scanning electron microscopy, respectively; film thickness was examined with a surface ellipsometer. The photocatalytic properties under ultraviolet (UV) light irradiation were analyzed by evaluating the degradation ratio of methylene blue (MB) at a certain time. Antibacterial activities of selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. Results Films with 5 coating layers annealed at 700℃ showed the greatest photocatalytic activity in terms of MB decomposition under UV light irradiation. TiO2 thin films with 5 coating layers annealed at 700℃ exhibited the greatest antimicrobial activity under UV-A light irradiation. Conclusions These results provide promising guidance in prevention of demineralization by increasing antimicrobial activities of film coated brackets. PMID:27226960

  19. Studies on Nanostructure Aluminium Thin Film Coatings Deposited using DC magnetron Sputtering Process

    NASA Astrophysics Data System (ADS)

    Singh M, Muralidhar; G, Vijaya; MS, Krupashankara; Sridhara, B. K.; Shridhar, T. N.

    2016-09-01

    Nanostructured thin film metallic coatings has become an area of intense research particularly in applications related solar, sensor technologies and many other optical applications such as laser windows, mirrors and reflectors. Thin film metallic coatings were deposited using DC magnetron sputtering process. The deposition rate was varied to study its influence on optical behavior of Aluminum thin films at a different argon flow rate. Studies on the optical response of these nanostructure thin film coatings were characterized using UV-VIS-NIR spectrophotometer with integrating sphere in the wavelength range of (250-2500nm) and Surface morphology were carried out using atomic force microscope with roughness ranging from 2 to 20nm and thickness was measured using Dektak measuring instrument. The reflection behavior of aluminium coatings on polycarbonate substrates has been evaluated. UV-VIS-NIR Spectrophotometer analysis indicates higher reflectance of 96% for all the films in the wavelength range of 250 nm to 2500 nm. Nano indentation study revealed that there was a considerable change in hardness values of the films prepared at different conditions.

  20. Study of two different thin film coating methods in transmission laser micro-joining of thin Ti-film coated glass and polyimide for biomedical applications.

    PubMed

    Sultana, T; Georgiev, G L; Baird, R J; Auner, G W; Newaz, G; Patwa, R; Herfurth, H J

    2009-07-01

    Biomedical devices and implants require precision joining for hermetic sealing which can be achieved with low power lasers. The effect of two different thin metal film coating methods was studied in transmission laser micro-joints of titanium-coated glass and polyimide. The coating methods were cathodic arc physical vapor deposition (CA-PVD) and electron beam evaporation (EB-PVD). Titanium-coated glass joined to polyimide film can have neural electrode application. The improvement of the joint quality will be essential for robust performance of the device. Low power fiber laser (wave length = 1100 nm) was used for transmission laser micro-joining of thin titanium (Ti) film (approximately 200 nm) coated Pyrex borosilicate 7740 glass wafer (0.5 mm thick) and polyimide (Imidex) film (0.2 mm thick). Ti film acts as the coupling agent in the joining process. The Ti film deposition rate in the CA-PVD was 5-10 A/s and in the EB-PVD 1.5 A/s. The laser joint strength was measured by a lap shear test, the Ti film surfaces were analyzed by atomic force microscopy (AFM) and the lap shear tested joints were analyzed by optical microscopy and scanning electron microscopy (SEM). The film properties and the failure modes of the joints were correlated to joint strength. The CA-PVD produced around 4 times stronger laser joints than EB-PVD. The adhesion of the Ti film on glass by CA-PVD is better than that of the EB-PVD method. This is likely to be due to a higher film deposition rate and consequently higher adhesion or sticking coefficient for the CA-PVD particles arriving on the substrate compared to that of the EB-PVD film. EB-PVD shows poor laser bonding properties due to the development of thermal hotspots which occurs from film decohesion.

  1. Conductivity of PEDOT:PSS on Spin-Coated and Drop Cast Nanofibrillar Cellulose Thin Films

    NASA Astrophysics Data System (ADS)

    Valtakari, Dimitar; Liu, Jun; Kumar, Vinay; Xu, Chunlin; Toivakka, Martti; Saarinen, Jarkko J.

    2015-10-01

    Aqueous dispersion of conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) was deposited on spin-coated and drop cast nanofibrillar cellulose (NFC)-glycerol (G) matrix on a glass substrate. A thin glycerol film was utilized on plasma-treated glass substrate to provide adequate adhesion for the NFC-glycerol (NFC-G) film. The effects of annealing temperature, the coating method of NFC-G, and the coating time intervals on the electrical performance of the PEDOT:PSS were characterized. PEDOT:PSS on drop cast NFC-G resulted in 3 orders of magnitude increase in the electrical conductivity compared to reference PEDOT:PSS film on a reference glass substrate, whereas the optical transmission was only slightly decreased. The results point out the importance of the interaction between the PEDOT:PSS and the NFC-G for the electrical and barrier properties for thin film electronics applications.

  2. Marangoni effects on a thin liquid film coating a sphere with axial or radial thermal gradients

    NASA Astrophysics Data System (ADS)

    Kang, Di; Nadim, Ali; Chugunova, Marina

    2016-11-01

    We study the time evolution of a thin liquid film coating the outer surface of a sphere in the presence of gravity, surface tension and thermal gradients. We derive the fourth-order nonlinear partial differential equation that models the thin film dynamics, including Marangoni terms arising from the dependence of surface tension on temperature. We consider two different heating regimes with axial or radial thermal gradients. We analyze the stability of a uniform coating under small perturbations and carry out numerical simulations in COMSOL for a range of parameter values. In the case of an axial temperature gradient, we find steady states with either uniform film thickness, or with drops forming at the top or bottom of the sphere, depending on the total volume of liquid in the film, dictating whether gravity or Marangoni effects dominate. In the case of a radial temperature gradient, a stability analysis reveals the most unstable non-axisymmetric modes on an initially uniform coating film.

  3. Application of Pcvd Process to Uniform Coating of TiO2 Thin Films on Polypropylene Beads

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Joo; Pham, Hung Cuong; Kim, Kyo-Seon

    The growth of the TiO2 thin films coated on the polypropylene beads was analyzed experimentally in a rotating cylindrical plasma chemical vapor deposition (PCVD) reactor. The precursors for the thin films were generated by plasma reactions, and they deposited on the polypropylene beads to become the uniform thin films. The TiO2 thin films grow more quickly on the polypropylene beads by increasing the mass flow rate of TTIP, or the rotation speed of the reactor. The smaller number of polypropylene beads in the reactor increases the growth rate of the thin films. The high-quality TiO2 thin films can be coated on particles uniformly by using the rotating cylindrical PCVD process. The particles coated with high-quality TiO2 thin films can be applied to the removal of air and water pollutants by a photodegradation reaction of TiO2.

  4. Spectral angle resolved scattering of thin film coatings.

    PubMed

    Schröder, Sven; Unglaub, David; Trost, Marcus; Cheng, Xinbin; Zhang, Jinlong; Duparré, Angela

    2014-02-01

    The light scattering of interference coatings is strongly dependent on the wavelength. In addition to the general strong increase of scattering as the wavelengths get shorter, dramatic scatter effects in and around the resonance regions can occur. This is discussed in detail for highly reflective and chirped mirrors. A new instrument is presented which enables spectral angle resolved scatter measurements of high-quality optical components to be performed between 250 and 1500 nm.

  5. Self-Healing Glassy Thin Coating for High-Temperature Applications.

    PubMed

    Castanié, Sandra; Carlier, Thibault; Méar, François O; Saitzek, Sébastien; Blach, Jean-François; Podor, Renaud; Montagne, Lionel

    2016-02-17

    Glass thin films (with nanometer to micrometer thicknesses) are promising in numerous applications, both as passive coatings and as active components. Self-healing is a feature of many current technological developments as a means of increasing the lifetime of materials. In the context of these developments, we report on the elaboration of the first self-healing glassy thin-film coating developed specifically for high-temperature applications. This coating is obtained by pulsed laser deposition of alternating layers of vanadium boride (VB) and a multicomponent oxide glass. Self-healing is obtained through the oxidation of VB at the operating temperature. The investigation of the effect of elaboration parameters on the coating composition and morphology made it possible to obtain up to seven-layer coatings, with good homogeneity and perfect interfaces, and with a total thickness of less than 1 μm. The autonomic self-healing capacity of the coating has been demonstrated by an in situ experiment, which shows that a crack of nanometric dimension can be healed within a few minutes at 700 °C.

  6. Thin coatings for heavy industry: Advanced coatings for pipes and valves

    NASA Astrophysics Data System (ADS)

    Vernhes, Luc

    Pipes and valves are pressure vessels that regulate the flow of materials (liquids, gases, and slurries) by controlling the passageways. To optimize processes, reduce costs, and comply with government regulations, original equipment manufacturers (OEMs) must maintain their products in state-of-the-art condition. The first valves were invented over 3,000 years ago to supply water to farms and cities. They were made with bronze alloys, providing good corrosion resistance and acceptable tribological performance. The industrial revolution drove manufacturers to develop new and improved tribological materials. In the 20th century, innovative alloys such as Monel copper-nickel and Stellite cobalt-chrome as well as hard chrome plating were introduced to better control tribological properties and maximize in-service life. Since then, new materials have been regularly introduced to extend the range of applications for valves. For example, Teflon fluoropolymers are used in corrosive chemical and petrochemical processes, the nickel-based superalloys Hastelloy and Inconel for petrochemical applications, and creep-resistant chromium-rich F91 steel for supercritical power plants. Recently, the valve industry has embraced the use of hard thermal sprayed coatings for the most demanding applications, and is investing heavily in research to develop the most suitable coatings for specific uses. There is increasing evidence that the optimal solution to erosive, corrosive, and fretting wear problems lies in the design and manufacture of multi-layer, graded, and/or nanostructured coatings and coating systems that combine controlled hardness with high elastic modulus, high toughness, and good adhesion. The overall objectives of this thesis were 1) to report on advances in the development of structurally controlled hard protective coatings with tailored mechanical, elastoplastic, and thermal properties; and 2) to describe enhanced wear-, erosion-, and corrosion-resistance and other

  7. Emissivity of freestanding membranes with thin metal coatings

    SciTech Connect

    Zwol, P. J. van Vles, D. F.; Voorthuijzen, W. P.; Péter, M.; Vermeulen, H.; Zande, W. J. van der; Sturm, J. M.; Kruijs, R. W. E. van de; Bijkerk, F.

    2015-12-07

    Freestanding silicon nitride membranes with thicknesses down to a few tens of nanometers find use as TEM windows or soft X-ray spectral purity filters. As the thickness of a membrane decreases, emissivity vanishes, which limits radiative heat emission and resistance to heat loads. We show that thin metal layers with thicknesses in the order of 1 nm enhance the emissivity of thin membranes by two to three orders of magnitude close to the theoretical limit of 0.5. This considerably increases thermal load capacity of membranes in vacuum environments. Our experimental results are in line with classical theory in which we adapt thickness dependent scattering terms in the Drude and Lorentz oscillators.

  8. Perfectly absorbing ultra thin interference coatings for hydrogen sensing.

    PubMed

    Serhatlioglu, Murat; Ayas, Sencer; Biyikli, Necmi; Dana, Aykutlu; Solmaz, Mehmet E

    2016-04-15

    Here we numerically demonstrate a straightforward method for optical detection of hydrogen gas by means of absorption reduction and colorimetric indication. A perfectly absorbing metal-insulator-metal (MIM) thin film interference structure is constructed using a silver metal back reflector, silicon dioxide insulator, and palladium as the upper metal layer and hydrogen catalyst. The thickness of silicon dioxide allows the maximizing of the electric field intensity at the Air/SiO2 interface at the quarter wavelengths and enabling perfect absorption with the help of highly absorptive palladium thin film (∼7 nm). While the exposure of the MIM structure to H2 moderately increases reflection, the relative intensity contrast due to formation of metal hydride is extensive. By modifying the insulator film thickness and hence the spectral absorption, the color is tuned and eye-visible results are obtained.

  9. Nanoindentation study of electrodeposited Ag thin coating: An inverse calculation of anisotropic elastic-plastic properties

    SciTech Connect

    Cheng, Guang; Sun, Xin; Wang, Yuxin; Tay, See Leng; Gao, Wei

    2017-01-01

    A new inverse method was proposed to calculate the anisotropic elastic-plastic properties (flow stress) of thin electrodeposited Ag coating utilizing nanoindentation tests, previously reported inverse method for isotropic materials and three-dimensional (3-D) finite element analyses (FEA). Indentation depth was ~4% of coating thickness (~10 μm) to avoid substrate effect and different indentation responses were observed in the longitudinal (L) and the transverse (T) directions. The estimated elastic-plastic properties were obtained in the newly developed inverse method by matching the predicted indentation responses in the L and T directions with experimental measurements considering indentation size effect (ISE). The results were validated with tensile flow curves measured from free-standing (FS) Ag film. The current method can be utilized to characterize the anisotropic elastic-plastic properties of coatings and to provide the constitutive properties for coating performance evaluations.

  10. Bimodal Latex Effect on Spin-Coated Thin Conductive Polymer-Single-Walled Carbon Nanotube Layers.

    PubMed

    Moradi, Mohammad-Amin; Larrakoetxea Angoitia, Katalin; van Berkel, Stefan; Gnanasekaran, Karthikeyan; Friedrich, Heiner; Heuts, Johan P A; van der Schoot, Paul; van Herk, Alex M

    2015-11-10

    We synthesize two differently sized poly(methyl methacrylate-co-tert-butyl acrylate) latexes by emulsion polymerization and mix these with a sonicated single-walled carbon nanotube (SWCNT) dispersion, in order to prepare 3% SWCNT composite mixtures. We spin-coat these mixtures at various spin-speed rates and spin times over a glass substrate, producing a thin, transparent, solid, conductive layer. Keeping the amount of SWCNTs constant, we vary the weight fraction of our smaller 30-nm latex particles relative to the larger 70-nm-sized ones. We find a maximum in the electrical conductivity up to 370 S/m as a function of the weight fraction of smaller particles, depending on the overall solid content, the spin speed, and the spin time. This maximum occurs at 3-5% of the smaller latex particles. We also find a more than 2-fold increase in conductivity parallel to the radius of spin-coating than perpendicular to it. Atomic force microscopy points at the existence of lanes of latex particles in the spin-coated thin layer, while large-area transmission electron microscopy demonstrates that the SWCNTs are aligned over a grid fixed on the glass substrate during the spin-coating process. We extract the conductivity distribution on the surface of the thin film and translate this into the direction of the SWCNTs in it.

  11. Spin Coated Nano Scale PMMA Films for Organic Thin Film Transistors

    NASA Astrophysics Data System (ADS)

    Shekar, B. Chandar; Sathish, S.; Sengoden, R.

    Nano scale poly methyl methacrylate (PMMA) films are prepared by spin coating the solution of PMMA on to p-Si substrate. The thickness of the films coated is measured by Ellipsometry. The SA-XRD spectrum of the as grown and annealed films indicated the amorphous nature. The SEM analysis revealed no pinholes, pits and dendritic features on the surface. Both as grown and annealed films indicated smooth surface and amorphous structure. The capacitance-voltage (C-V) behaviour of the metal-insulator-semiconductor (MIS) structure with Al/PMMA/p-Si has been studied. The C-V behaviour carried out for various frequencies (f) ranging from 20 kHz to 1 MHz and for a bias voltage range of -20 V to +20 V. Both as grown and annealed films showed a small flat band voltage (VFB) shift towards the negative voltage. The small shift in the VFB observed may be due to charge traps and de-traps. The obtained C-V behaviour for as grown and annealed films indicated that as grown PMMA nano scale thin films do not have many defects such as voids and inhomogeneity etc. The observed C-V behavior, a very low shift in the flat band voltage (VFB 0); reasonably higher dielectric constant values; thermal stability up to 2800C; amorphous and smooth surface implies that nano scale thin PMMA film coated by spin coating could be used as an efficient dielectric layer in field effect organic thin film transistors (OTFTs).

  12. Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives

    NASA Astrophysics Data System (ADS)

    Na, Jin Yeong; Kang, Boseok; Sin, Dong Hun; Cho, Kilwon; Park, Yeong Don

    2015-08-01

    Spin-coating has been used extensively in the fabrication of electronic devices; however, the effects of the processing parameters have not been fully explored. Here, we systematically characterize the effects of the spin-coating time on the microstructure evolution during semiconducting polymer solidification in an effort to establish the relationship between this parameter and the performances of the resulting polymer field-effect transistors (FETs). We found that a short spin-coating time of a few seconds dramatically improve the morphology and molecular order in a conjugated polymer thin film because the π-π stacking structures formed by the polymer molecules grow slowly and with a greater degree of order due to the residual solvent present in the wet film. The improved ordering is correlated with improved charge carrier transport in the FETs prepared from these films. We also demonstrated the effects of various processing additives on the resulting FET characteristics as well as on the film drying behavior during spin-coating. The physical properties of the additives are found to affect the film drying process and the resulting device performance.

  13. Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives

    PubMed Central

    Na, Jin Yeong; Kang, Boseok; Sin, Dong Hun; Cho, Kilwon; Park, Yeong Don

    2015-01-01

    Spin-coating has been used extensively in the fabrication of electronic devices; however, the effects of the processing parameters have not been fully explored. Here, we systematically characterize the effects of the spin-coating time on the microstructure evolution during semiconducting polymer solidification in an effort to establish the relationship between this parameter and the performances of the resulting polymer field-effect transistors (FETs). We found that a short spin-coating time of a few seconds dramatically improve the morphology and molecular order in a conjugated polymer thin film because the π-π stacking structures formed by the polymer molecules grow slowly and with a greater degree of order due to the residual solvent present in the wet film. The improved ordering is correlated with improved charge carrier transport in the FETs prepared from these films. We also demonstrated the effects of various processing additives on the resulting FET characteristics as well as on the film drying behavior during spin-coating. The physical properties of the additives are found to affect the film drying process and the resulting device performance. PMID:26299676

  14. Understanding Solidification of Polythiophene Thin Films during Spin-Coating: Effects of Spin-Coating Time and Processing Additives.

    PubMed

    Na, Jin Yeong; Kang, Boseok; Sin, Dong Hun; Cho, Kilwon; Park, Yeong Don

    2015-08-24

    Spin-coating has been used extensively in the fabrication of electronic devices; however, the effects of the processing parameters have not been fully explored. Here, we systematically characterize the effects of the spin-coating time on the microstructure evolution during semiconducting polymer solidification in an effort to establish the relationship between this parameter and the performances of the resulting polymer field-effect transistors (FETs). We found that a short spin-coating time of a few seconds dramatically improve the morphology and molecular order in a conjugated polymer thin film because the π-π stacking structures formed by the polymer molecules grow slowly and with a greater degree of order due to the residual solvent present in the wet film. The improved ordering is correlated with improved charge carrier transport in the FETs prepared from these films. We also demonstrated the effects of various processing additives on the resulting FET characteristics as well as on the film drying behavior during spin-coating. The physical properties of the additives are found to affect the film drying process and the resulting device performance.

  15. Ultra-Thin Pyrocarbon Films as a Versatile Coating Material

    NASA Astrophysics Data System (ADS)

    Kaplas, Tommi; Kuzhir, Polina

    2017-02-01

    The properties and synthesis procedures of the nanometrically thin pyrolyzed photoresist films (PPF) and the pyrolytic carbon films (PCF) were compared, and a number of similarities were found. Closer examination showed that the optical properties of these films are almost identical; however, the DC resistance of PPF is about three times higher than that of PCF. Moreover, we observed that the wettability of amorphous PPF and PCF was almost comparable to crystalline graphite. Potential applications executed by utilizing the small difference in the synthesis procedure of these two materials are suggested.

  16. Ultra-Thin Pyrocarbon Films as a Versatile Coating Material.

    PubMed

    Kaplas, Tommi; Kuzhir, Polina

    2017-12-01

    The properties and synthesis procedures of the nanometrically thin pyrolyzed photoresist films (PPF) and the pyrolytic carbon films (PCF) were compared, and a number of similarities were found. Closer examination showed that the optical properties of these films are almost identical; however, the DC resistance of PPF is about three times higher than that of PCF. Moreover, we observed that the wettability of amorphous PPF and PCF was almost comparable to crystalline graphite. Potential applications executed by utilizing the small difference in the synthesis procedure of these two materials are suggested.

  17. Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains

    NASA Astrophysics Data System (ADS)

    Diao, Ying; Tee, Benjamin C.-K.; Giri, Gaurav; Xu, Jie; Kim, Do Hwan; Becerril, Hector A.; Stoltenberg, Randall M.; Lee, Tae Hoon; Xue, Gi; Mannsfeld, Stefan C. B.; Bao, Zhenan

    2013-07-01

    Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach—termed fluid-enhanced crystal engineering (FLUENCE)—that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm2 V-1 s-1 and 11 cm2 V-1 s-1. FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics.

  18. Sorbent coated glass wool fabric as a thin film microextraction device.

    PubMed

    Riazi Kermani, Farhad; Pawliszyn, Janusz

    2012-11-06

    A new approach for thin film microextraction (TFME) with mixed-phase sorptive coating is presented. Carboxen/polydimethylsiloxane (CAR/PDMS) and polydimethylsiloxane/divinylbenzene (PDMS/DVB) TFME samplers were prepared using spin coating and glass wool fabric mesh as substrate. The samplers were easily tailored in size and shape by cutting tools. Good durability and flat-shape stability were observed during extraction, stirring in water, and thermal desorption. The latter characteristic obviates the need for an extra framed holder for rapid TFME and makes the samplers more robust and easier to deploy. The samplers combine the advantages of adsorptive solid-phase microextraction (SPME) and TFME, including one-step solvent-free extraction and preconcentration, direct thermal desorption, and enhanced sensitivity without sacrificing analysis time due to thin film geometry. The analytical performance of these new devices was demonstrated using water samples spiked with N-nitrosamines (NAs) as model compounds. Over an order of magnitude enhancement of extraction efficiencies was obtained for the model compounds compared with the SPME fibers of similar coatings and PDMS thin film membrane. The results of this study indicate that these novel thin film devices are promising for rapid and efficient microextraction of polar analytes in water.

  19. Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains.

    PubMed

    Diao, Ying; Tee, Benjamin C-K; Giri, Gaurav; Xu, Jie; Kim, Do Hwan; Becerril, Hector A; Stoltenberg, Randall M; Lee, Tae Hoon; Xue, Gi; Mannsfeld, Stefan C B; Bao, Zhenan

    2013-07-01

    Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach--termed fluid-enhanced crystal engineering (FLUENCE)--that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm(2) V(-1) s(-1) and 11 cm(2) V(-1) s(-1). FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics.

  20. Long-term corrosion protection by a thin nano-composite coating

    NASA Astrophysics Data System (ADS)

    Ejenstam, Lina; Tuominen, Mikko; Haapanen, Janne; Mäkelä, Jyrki M.; Pan, Jinshan; Swerin, Agne; Claesson, Per M.

    2015-12-01

    We report and discuss the corrosion protective properties of a thin nano-composite coating system consisting of an 11 μm thick polyester acrylate (PEA) basecoat, covered by an approximately 1-2 μm thick layer of TiO2 nanoparticles carrying a 0.05 μm thick hexamethyl disiloxane (HMDSO) top coat. The corrosion protective properties were evaluated on carbon steel substrates immersed in 3 wt% NaCl solution by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) measurements. The protective properties of each layer, and of each pair of layers, were also evaluated to gain further understanding of the long-term protective properties offered by the nano-composite coating. The full coating system showed excellent corrosion protective properties in the corrosive environment of 3 wt% NaCl-solution for an extended period of 100 days, during which the coating impedance, at the lower frequency limit (0.01 Hz), remained above 108 Ω cm2. We suggest that the excellent corrosion protective properties of the complete coating system is due to a combination of (i) good adhesion and stability of the PEA basecoat, (ii) the surface roughness and the elongated diffusion path provided by the addition of TiO2 nanoparticles, and (iii) the low surface energy provided by the HMDSO top coat.

  1. Low earth orbit environmental effects on osmium and related optical thin-film coatings

    NASA Technical Reports Server (NTRS)

    Gull, T. R.; Herzig, H.; Osantowski, J. F.; Toft, A. R.

    1985-01-01

    A number of samples of optical thin film materials were flown on Shuttle flight STS-8 as part of an experiment to evaluate their interaction with residual atomic oxygen in low earth orbit. Osmium was selected because of its usefulness as a reflective optical coating for far-UV instruments and for confirmation of results from previous Shuttle flights in which such coatings disappeared. Reflectance data and photographic evidence are presented to support the hypothesis that the osmium disappearance is due to reaction with oxygen to form a volatile oxide. Platinum and iridium, which were included for comparison, fared much better.

  2. Solar Selective Coatings Prepared From Thin-Film Molecular Mixtures and Evaluated

    NASA Technical Reports Server (NTRS)

    Jaworske, Don A.

    2003-01-01

    Thin films composed of molecular mixtures of metal and dielectric are being considered for use as solar selective coatings for a variety of space power applications. By controlling molecular mixing during ion-beam sputter deposition, researchers can tailor the solar selective coatings to have the combined properties of high solar absorptance and low infrared emittance. On orbit, these combined properties simultaneously maximize the amount of solar energy captured by the coating and minimize the amount of thermal energy radiated. The solar selective coatings are envisioned for use on minisatellites, for applications where solar energy is used to power heat engines or to heat remote regions in the interior of the spacecraft. Such systems may be useful for various missions, particularly those to middle Earth orbit. Sunlight must be concentrated by a factor of 100 or more to achieve the desired heat inlet operating temperature. At lower concentration factors, the temperature of the heat inlet surface of the heat engine is too low for efficient operation, and at high concentration factors, cavity type heat receivers become attractive. The an artist's concept of a heat engine, with the annular heat absorbing surface near the focus of the concentrator coated with a solar selective coating is shown. In this artist's concept, the heat absorbing surface powers a small Stirling convertor. The astronaut's gloved hand is provided for scale. Several thin-film molecular mixtures have been prepared and evaluated to date, including mixtures of aluminum and aluminum oxide, nickel and aluminum oxide, titanium and aluminum oxide, and platinum and aluminum oxide. For example, a 2400- Angstrom thick mixture of titanium and aluminum oxide was found to have a solar absorptance of 0.93 and an infrared emittance of 0.06. On the basis of tests performed under flowing nitrogen at temperatures as high as 680 C, the coating appeared to be durable at elevated temperatures. Additional durability

  3. Rayleigh instability in polymer thin films coated in the nanopores of anodic aluminum oxide templates.

    PubMed

    Tsai, Chia-Chan; Chen, Jiun-Tai

    2014-01-14

    We study the Rayleigh instability of polystyrene (PS) thin films coated in the nanopores of anodic aluminum oxide (AAO) templates. After thermal annealing, the surface of the PS thin films undulates and the nanostructures transform from nanotubes to Rayleigh-instability-induced nanostructures (short nanorods with encapsulated air bubbles). With longer annealing times, the nanostructures further transform to nanorods with longer lengths. PS samples with two different molecular weights (24 and 100 kg/mol) are used, and their instability transformation processes are compared. The morphology diagrams of the nanostructures at different stages are also constructed to elucidate the mechanism of the morphology transformation.

  4. Postdeposition treatment of IBS coatings for UV applications with optimized thin-film stress properties.

    PubMed

    Bischoff, Martin; Nowitzki, Tobias; Voß, Oliver; Wilbrandt, Steffen; Stenzel, Olaf

    2014-02-01

    Ion-beam-sputtering (IBS) single-layer and multilayer coating designs for UV applications were examined after the deposition process as well as after a defined postdeposition treatment. High internal compressive film stress as well as moderate absorption losses in the UV spectral range were measured at the as-deposited thin films. Due to a controlled postdeposition treatment process, the absorption losses and the high compressive stress can be reduced significantly. We show that the remaining thin-film stress of SiO2 and HfO2 multilayer designs can be specifically manipulated by the parameters of the postdeposition treatment. Even zero and tensile stress can be achieved for complex multilayer coatings.

  5. Near-field radiative heat transfer between metamaterials coated with silicon carbide thin films

    SciTech Connect

    Basu, Soumyadipta Yang, Yue; Wang, Liping

    2015-01-19

    In this letter, we study the near-field radiative heat transfer between two metamaterial substrates coated with silicon carbide (SiC) thin films. It is known that metamaterials can enhance the near-field heat transfer over ordinary materials due to excitation of magnetic plasmons associated with s polarization, while strong surface phonon polariton exists for SiC. By careful tuning of the optical properties of metamaterial, it is possible to excite electrical and magnetic resonances for the metamaterial and surface phonon polaritons for SiC at different spectral regions, resulting in the enhanced heat transfer. The effect of the SiC film thickness at different vacuum gaps is investigated. Results obtained from this study will be beneficial for application of thin film coatings for energy harvesting.

  6. Setup for high-temperature surface Brillouin light scattering: Application to opaque thin films and coatings

    NASA Astrophysics Data System (ADS)

    Faurie, D.; Girodon-Boulandet, N.; Kaladjian, A.; Challali, F.; Abadias, G.; Djemia, P.

    2017-02-01

    A setup combining surface Brillouin light scattering with a high-temperature chamber has been developed. The temperature of the sample is controlled with a Bühler HDK chamber for optical measurements (maximum temperature of 1600 °C), in controlled atmospheres or high vacuum (10-6 mbar). This setup allows the study of sound velocity of surface acoustic waves and of the elastic constants of opaque thin films and coatings in situ as a function of temperature from surface Brillouin light scattering, by analyzing the backscattered light from the sample at a fixed angle of incidence. In this paper, we will demonstrate the applications of this setup for metallic glass thin films devitrification study and evaluation of high temperature elastic properties of hard nitride coatings. This kind of study using surface acoustic waves is rare, in contrast to those made on transparent bulk materials.

  7. Durable thin film coatings for reflectors used in low earth orbit

    NASA Technical Reports Server (NTRS)

    Mcclure, Donald J.

    1989-01-01

    This paper discusses the properties of thin film coatings used to provide a durable reflective surface for solar concentrators used in the solar dynamic system designed for the Space Station. The material system to be used consists of an adhesion promotion layer, a silver reflective layer, and a protective layer of aluminum oxide and silicon dioxide. The performance characteristics of this system are described and compared to those of several alternative systems which use aluminum as the reflective layer.

  8. Thin film transistors on plastic substrates with reflective coatings for radiation protection

    DOEpatents

    Wolfe, Jesse D.; Theiss, Steven D.; Carey, Paul G.; Smith, Patrick M.; Wickboldt, Paul

    2003-11-04

    Fabrication of silicon thin film transistors (TFT) on low-temperature plastic substrates using a reflective coating so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The TFT can be used in large area low cost electronics, such as flat panel displays and portable electronics such as video cameras, personal digital assistants, and cell phones.

  9. Thin film transistors on plastic substrates with reflective coatings for radiation protection

    DOEpatents

    Wolfe, Jesse D.; Theiss, Steven D.; Carey, Paul G.; Smith, Patrick M.; Wickbold, Paul

    2006-09-26

    Fabrication of silicon thin film transistors (TFT) on low-temperature plastic substrates using a reflective coating so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The TFT can be used in large area low cost electronics, such as flat panel displays and portable electronics such as video cameras, personal digital assistants, and cell phones.

  10. Structure and morphology of thin films of linear aliphatic polyesters prepared by spin-coating.

    PubMed

    Hernández, J J; Rueda, D R; García-Gutiérrez, M C; Nogales, A; Ezquerra, T A; Soccio, M; Lotti, N; Munari, A

    2010-07-06

    Thin films, with thicknesses from 10 to 400 nm of linear aliphatic polyesters (X, Y), based on propylenediol (X = 3) and on dicarboxylic acid of different chain length (Y = 2, 3, and 4 CH(2) units) were prepared by spin coating of CHCl(3) polymer solutions with different polymer concentrations. Morphology and structure of the spin coated thin films were investigated by atomic force microscopy (AFM) and by grazing incidence X-ray scattering techniques at small, (GISAXS) and wide angles (GIWAXS). AFM revealed a strong dewetting for all three polymers for coatings thinner than 100 nm. The polymer films are clearly semicrystalline for thicknesses higher than 50 nm. GIWAXS of the thicker films revealed their oriented crystalline nature. An edge-on-lamellae morphology is clearly shown by the AFM-phase images even for relatively thin films. SAXS with the beam parallel to the sample plane also support the presence of lamellae perpendicular to the substrate. The use of a mu-beam helped to interpret the GIWAXS patterns and allowed to obtain oriented WAXS patterns from melt solidified filaments. Thus, a crystal chain packing is proposed for the three polymers and consequently the indexing of the observed reflections. Accordingly, the polymer chains lie parallel to the substrate being the bc plane of the monoclinic crystal unit cell parallel to the substrate.

  11. Finite difference time domain method for simulation of damage initiation in thin film coatings

    NASA Astrophysics Data System (ADS)

    Smalakys, Linas; Momgaudis, Balys; Grigutis, Robertas; Melninkaitis, Andrius

    2016-12-01

    Time resolved digital holography (TRDH) is a versatile tool that provides valuable insights into the dynamics of femtosecond damage initiation by providing spatiotemporal information of excited material. However, interpreting of TRDH data in thin film dielectric coatings is rather complicated without appropriate theoretical models that are able to correctly describe underlying nature of damage formation. Therefore, a model based on finite difference time domain (FDTD) method with complete Keldysh theory for nonlinear ionization of atoms and multiple rate equation (MRE) method for conduction band electrons was developed. The model was used to reproduce both temporal and spatial characteristics of TRDH experiment performed on Ta2O5 dielectric coating. Fitted material parameters were then applied to indirectly estimate LIDT of the coating.

  12. Space Plasma Testing of High-Voltage Thin-Film Solar Arrays with Protective Coatings

    NASA Technical Reports Server (NTRS)

    Tlomak, Pawel; Hausgen, Paul E.; Merrill, John; Senft, Donna; Piszczor, Michael F., Jr.

    2007-01-01

    This paper gives an overview of the space plasma test program for thin-film photovoltaics (TFPV) technologies developed at the Air Force Research Laboratory (AFRL). The main objective of this program is to simulate the effects of space plasma characteristic of LEO and MEO environments on TFPV. Two types of TFPV, amorphous silicon (a-Si) and copper-indium-gallium-diselenide (CIGS), coated with two types of thin-film, multifunctional coatings were used for these studies. This paper reports the results of the first phase of this program, namely the results of preliminary electrostatic charging, arcing, dielectric breakdown, and collection current measurements carried out with a series of TFPV exposed to simulated space plasma at the NASA Glenn Plasma Interaction Facility. The experimental data demonstrate that multifunctional coatings developed for this program provide effective protection against the plasma environment while minimizing impact on power generation performance. This effort is part of an ongoing program led by the Space Vehicles Directorate at the AFRL devoted to the development and space qualification of TFPV and their protective coatings.

  13. Reduction of bacterial adhesion on dental composite resins by silicon-oxygen thin film coatings.

    PubMed

    Mandracci, Pietro; Mussano, Federico; Ceruti, Paola; Pirri, Candido F; Carossa, Stefano

    2015-01-29

    Adhesion of bacteria on dental materials can be reduced by modifying the physical and chemical characteristics of their surfaces, either through the application of specific surface treatments or by the deposition of thin film coatings. Since this approach does not rely on the use of drugs or antimicrobial agents embedded in the materials, its duration is not limited by their possible depletion. Moreover it avoids the risks related to possible cytotoxic effects elicited by antibacterial substances released from the surface and diffused in the surrounding tissues. In this work, the adhesion of Streptococcus mutans and Streptococcus mitis was studied on four composite resins, commonly used for manufacturing dental prostheses. The surfaces of dental materials were modified through the deposition of a-SiO(x) thin films by plasma enhanced chemical vapor deposition. The chemical bonding structure of the coatings was analyzed by Fourier-transform infrared spectroscopy. The morphology of the dental materials before and after the coating deposition was assessed by means of optical microscopy and high-resolution mechanical profilometry, while their wettability was investigated by contact angle measurements. The sample roughness was not altered after coating deposition, while a noticeable increase of wettability was detected for all the samples. Also, the adhesion of S. mitis decreased in a statistically significant way on the coated samples, when compared to the uncoated ones, which did not occur for S. mutans. Within the limitations of this study, a-SiO(x) coatings may affect the adhesion of bacteria such as S. mitis, possibly by changing the wettability of the composite resins investigated.

  14. Biocompatibility evaluation of sputtered zirconium-based thin film metallic glass-coated steels

    PubMed Central

    Subramanian, Balasubramanian; Maruthamuthu, Sundaram; Rajan, Senthilperumal Thanka

    2015-01-01

    Thin film metallic glasses comprised of Zr48Cu36Al8Ag8 (at.%) of approximately 1.5 μm and 3 μm in thickness were prepared using magnetron sputtering onto medical grade 316L stainless steel. Their structural and mechanical properties, in vitro corrosion, and antimicrobial activity were analyzed. The amorphous thin film metallic glasses consisted of a single glassy phase, with an absence of any detectable peaks corresponding to crystalline phases. Elemental composition close to the target alloy was noted from EDAX analysis of the thin film. The surface morphology of the film showed a smooth surface on scanning electron microscopy and atomic force microscopy. In vitro electrochemical corrosion studies indicated that the zirconium-based metallic glass could withstand body fluid, showing superior resistance to corrosion and electrochemical stability. Interactions between the coated surface and bacteria were investigated by agar diffusion, solution suspension, and wet interfacial contact methods. The results indicated a clear zone of inhibition against the growth of microorganisms such as Escherichia coli and Staphylococcus aureus, confirming the antimicrobial activity of the thin film metallic glasses. Cytotoxicity studies using L929 fibroblast cells showed these coatings to be noncytotoxic in nature. PMID:26491304

  15. TiO2 nanoparticle thin film-coated optical fiber Fabry-Perot sensor.

    PubMed

    Jiang, Mingshun; Li, Qiu-Shun; Wang, Jun-Nan; Jin, Zhongwei; Sui, Qingmei; Ma, Yaohong; Shi, Jianguo; Zhang, Faye; Jia, Lei; Yao, Wei-Guo; Dong, Wen-Fei

    2013-02-11

    In this paper, a novel TiO(2) nanoparticle thin film coated optical fiber Fabry-Perot (F-P) sensor had been developed for refractive index (RI) sensing by monitoring the shifts of the fringe contrast in the reflectance spectra. Using in situ liquid phase deposition approach, the TiO(2) nanoparticle thin film could be formed on the fiber surface in a controlled fashion. The optical properties of as-prepared F-P sensors were investigated both theoretically and experimentally. The results indicated that the RI sensitivity of F-P sensors could be effectively improved after the deposition of nanoparticle thin-films. It was about 69.38 dB/RIU, which was 2.6 times higher than that of uncoated one. The linear RI measurement range was also extended from 1.333~1.457 to 1.333~1.8423. More importantly, its optical properties exhibited the unique temperature-independent performance. Therefore, owing to these special optical properties, the TiO(2) nanoparticle thin film coated F-P sensors have great potentials in medical diagnostics, food quality testing, environmental monitoring, biohazard detection and homeland security, even at elevated temperature.

  16. Biocompatibility evaluation of sputtered zirconium-based thin film metallic glass-coated steels.

    PubMed

    Subramanian, Balasubramanian; Maruthamuthu, Sundaram; Rajan, Senthilperumal Thanka

    2015-01-01

    Thin film metallic glasses comprised of Zr48Cu36Al8Ag8 (at.%) of approximately 1.5 μm and 3 μm in thickness were prepared using magnetron sputtering onto medical grade 316L stainless steel. Their structural and mechanical properties, in vitro corrosion, and antimicrobial activity were analyzed. The amorphous thin film metallic glasses consisted of a single glassy phase, with an absence of any detectable peaks corresponding to crystalline phases. Elemental composition close to the target alloy was noted from EDAX analysis of the thin film. The surface morphology of the film showed a smooth surface on scanning electron microscopy and atomic force microscopy. In vitro electrochemical corrosion studies indicated that the zirconium-based metallic glass could withstand body fluid, showing superior resistance to corrosion and electrochemical stability. Interactions between the coated surface and bacteria were investigated by agar diffusion, solution suspension, and wet interfacial contact methods. The results indicated a clear zone of inhibition against the growth of microorganisms such as Escherichia coli and Staphylococcus aureus, confirming the antimicrobial activity of the thin film metallic glasses. Cytotoxicity studies using L929 fibroblast cells showed these coatings to be noncytotoxic in nature.

  17. Mechanical measurements on lithium phosphorous oxynitride coated silicon thin film electrodes for lithium-ion batteries during lithiation and delithiation

    NASA Astrophysics Data System (ADS)

    Al-Obeidi, Ahmed; Kramer, Dominik; Boles, Steven T.; Mönig, Reiner; Thompson, Carl V.

    2016-08-01

    The development of large stresses during lithiation and delithiation drives mechanical and chemical degradation processes (cracking and electrolyte decomposition) in thin film silicon anodes that complicate the study of normal electrochemical and mechanical processes. To reduce these effects, lithium phosphorous oxynitride (LiPON) coatings were applied to silicon thin film electrodes. Applying a LiPON coating has two purposes. First, the coating acts as a stable artificial solid electrolyte interphase. Second, it limits mechanical degradation by retaining the electrode's planar morphology during cycling. The development of stress in LiPON-coated electrodes was monitored using substrate curvature measurements. LiPON-coated electrodes displayed highly reproducible cycle-to-cycle behavior, unlike uncoated electrodes which had poorer coulombic efficiency and exhibited a continual loss in stress magnitude with continued cycling due to film fracture. The improved mechanical stability of the coated silicon electrodes allowed for a better investigation of rate effects and variations of mechanical properties during electrochemical cycling.

  18. Dip coated nickel zinc oxide thin films: Structural, optical and magnetic investigations

    NASA Astrophysics Data System (ADS)

    Kayani, Zohra Nazir; Kiran, Faiza; Riaz, Saira; Zia, Rehana; Naseem, Shahzad

    2015-01-01

    Dip-coating technique was used to deposit NiZnO thin films on glass substrates at varying withdrawal speed in the range of 150-350 mm/s and annealed at 500 °C for 4 h. X-ray diffraction (XRD) results showed that the deposited NiZnO thin films have a pure wurtzite structure without any significant change in the structure caused by substituting Zn ion with Ni ion. Crystallite size increased from 248 to 497 nm with increase in withdrawal speed. Vibrating Sample magnetometer (VSM) results indicated that NiZnO thin films exhibit ferromagnetic properties. Increase in saturation magnetization with increase in withdrawal speed is observed. Evaluated optical band gap of the films reduced from 3.18 eV to 2.50 eV with the increase in withdrawal speed of the substrate.

  19. Dip coated TiO2 nanostructured thin film: synthesis and application

    NASA Astrophysics Data System (ADS)

    Vanaraja, Manoj; Muthukrishnan, Karthika; Boomadevi, Shanmugam; Karn, Rakesh Kumar; Singh, Vijay; Singh, Pramod K.; Pandiyan, Krishnamoorthy

    2016-02-01

    TiO2 thin film was fabricated by dip coating method using titanium IV chloride as precursor and sodium carboxymethyl cellulose as thickening as well as capping agent. Structural and morphological features of TiO2 thin film were characterized by X-ray diffractometer and field emission scanning electron microscope, respectively. Crystallinity of the film was confirmed with high-intensity peak at (101) plane, and its average crystallite size was found to be 28 nm. The ethanol-sensing properties of TiO2 thin film was studied by the chemiresistive method. Furthermore, various gases were tested in order to verify the selectivity of the sensor. Among the several gases, the fabricated TiO2 sensor showed very high selectivity towards ethanol at room temperature.

  20. Polyphenol Coating as an Interlayer for Thin-Film Composite Membranes with Enhanced Nanofiltration Performance.

    PubMed

    Zhang, Xi; Lv, Yan; Yang, Hao-Cheng; Du, Yong; Xu, Zhi-Kang

    2016-11-30

    Thin-film composite (TFC) nanofiltration membranes are prepared via interfacial polymerization with a polyphenol coating as an interlayer for the thin and smooth polyamide selective layer. The polyphenol interlayer is simply fabricated by the codeposition of tannic acid and diethylenetriamine without changing the surface morphology of the polysulfone ultrafiltration substrate. An interfacial polymerization is conducted from piperazidine and trimesoyl chloride on the polyphenol interlayer to construct the polyamide selective layer. The as-prepared TFC nanofiltration membranes show nearly tripled fold of water permeation flux as compared with those prepared at the same condition without an interlayer. They also exhibit a high rejection to Na2SO4 (>98%) because the thin and defect-free polyamide selective layer is formed on the polyphenol interlayer. These nanofiltration properties have high reproducibility, which means the TFC nanofiltration membranes are suitable for scale-up industrial applications.

  1. Hybrid Thin Film Organosilica Sol-Gel Coatings To Support Neuronal Growth and Limit Astrocyte Growth.

    PubMed

    Capeletti, Larissa Brentano; Cardoso, Mateus Borba; Dos Santos, João Henrique Zimnoch; He, Wei

    2016-10-07

    Thin films of silica prepared by a sol-gel process are becoming a feasible coating option for surface modification of implantable neural sensors without imposing adverse effects on the devices' electrical properties. In order to advance the application of such silica-based coatings in the context of neural interfacing, the characteristics of silica sol-gel are further tailored to gain active control of interactions between cells and the coating materials. By incorporating various readily available organotrialkoxysilanes carrying distinct organic functional groups during the sol-gel process, a library of hybrid organosilica coatings is developed and investigated. In vitro neural cultures using PC12 cells and primary cortical neurons both reveal that, among these different types of hybrid organosilica, the introduction of aminopropyl groups drastically transforms the silica into robust neural permissive substrate, supporting neuron adhesion and neurite outgrowth. Moreover, when this organosilica is cultured with astrocytes, a key type of glial cells responsible for glial scar response toward neural implants, such cell growth promoting effect is not observed. These findings highlight the potential of organo-group-bearing silica sol-gel to function as advanced coating materials to selectively modulate cell response and promote neural integration with implantable sensing devices.

  2. Models for the optical simulations of fractal aggregated soot particles thinly coated with non-absorbing aerosols

    NASA Astrophysics Data System (ADS)

    Wu, Yu; Cheng, Tianhai; Zheng, Lijuan; Chen, Hao

    2016-10-01

    Light absorption enhancement of aged soot aerosols is highly sensitive to the morphologies and mixing states of soot aggregates and their non-absorbing coatings, such as organic materials. The quantification of these effects on the optical properties of thinly coated soot aerosols is simulated using an effective model with fixed volume fractions. Fractal aggregated soot was simulated using the diffusion limited aggregation (DLA) algorithm and discretized into soot dipoles. The dipoles of non-absorbing aerosols, whose number was fixed by the volume fraction, were further generated from the neighboring random edge dipoles. Their optical properties were calculated using the discrete dipole approximation (DDA) method and were compared with other commonly used models. The optical properties of thinly coated soot calculated using the fixed volume fraction model are close to (less than ~10% difference) the results of the fixed coating thickness model, except their asymmetry parameters (up to ~25% difference). In the optical simulations of thinly coated soot aerosols, this relative difference of asymmetry parameters and phase functions between these realistic models may be notable. The realizations of the fixed volume fraction model may introduce smaller variation of optical results than those of the fixed coating thickness model. Moreover, the core-shell monomers model and homogeneous aggregated spheres model with the Maxwell-Garnett (MG) theory may underestimate (up to ~20%) the cross sections of thinly coated soot aggregates. The single core-shell sphere model may largely overestimate (up to ~150%) the cross sections and single scattering albedo of thinly coated soot aggregates, and it underestimated (up to ~60%) their asymmetry parameters. It is suggested that the widely used single core-shell sphere approximation may not be suitable for the single scattering calculations of thinly coated soot aerosols.

  3. Nanostructured ZnO thin films prepared by sol-gel spin-coating

    NASA Astrophysics Data System (ADS)

    Heredia, E.; Bojorge, C.; Casanova, J.; Cánepa, H.; Craievich, A.; Kellermann, G.

    2014-10-01

    ZnO thin films deposited on silica flat plates were prepared by spin-coating and studied by applying several techniques for structural characterization. The films were prepared by depositing different numbers of layers, each deposition being followed by a thermal treatment at 200 °C to dry and consolidate the successive layers. After depositing all layers, a final thermal treatment at 450 °C during 3 h was also applied in order to eliminate organic components and to promote the crystallization of the thin films. The total thickness of the multilayered films - ranging from 40 nm up to 150 nm - was determined by AFM and FESEM. The analysis by GIXD showed that the thin films are composed of ZnO crystallites with an average diameter of 25 nm circa. XR results demonstrated that the thin films also exhibit a large volume fraction of nanoporosity, typically 30-40 vol.% in thin films having thicknesses larger than ∼70 nm. GISAXS measurements showed that the experimental scattering intensity is well described by a structural model composed of nanopores with shape of oblate spheroids, height/diameter aspect ratio within the 0.8-0.9 range and average diameter along the sample surface plane in the 5-7 nm range.

  4. Photophysical property and photostability of J-aggregate thin films of thiacyanine dyes prepared by the spin-coating method.

    PubMed

    Tani, Katsuhiko; Ito, Chizuru; Hanawa, Yasuhiro; Uchida, Mamoru; Otaguro, Kunihiko; Horiuchi, Hiroaki; Hiratsuka, Hiroshi

    2008-01-24

    By use of electrostatic interactions of dye molecules and poly(diallyldimethylammonium chloride) (PDDA), the spin-coating technique has been successfully applied to the preparation of stable J-aggregate thin films of thiacarbocyanine dyes on a polycarbonate or quartz plate. The J-aggregate thin films were prepared by the spin-coating of PDDA aqueous solution on dye thin films prepared on a substrate by the spin-coating of 2,2,3,3-tetrafluoro-1-propanol solution of dyes. Photophysical properties of the dye thin films and J-aggregate thin films were studied by measuring the fluorescence spectra, quantum yields, and lifetimes. Coherent size of the J-aggregates was estimated to be 3-12 by means of the absorption bandwidth (full width at half maximum) or radiative lifetime. Photostability of the J-aggregate thin films was also studied in terms of photodegradation efficiency under argon and oxygen in comparison with the dye thin films, and J-aggregate thin films were found to be more stable than the corresponding dye thin films.

  5. The chocolate-egg problem: Fabrication of thin elastic shells through coating

    NASA Astrophysics Data System (ADS)

    Lee, Anna; Marthelot, Joel; Brun, Pierre-Thomas; Reis, Pedro M.

    2015-03-01

    We study the fabrication of thin polymeric shells based on the coating of a curved surface by a viscous fluid. Upon polymerization of the resulting thin film, a slender solid structure is delivered after demolding. This technique is extensively used, empirically, in manufacturing, where it is known as rotational molding, as well as in the food industry, e.g. for chocolate-eggs. This problem is analogous to the Landau-Levich-Derjaguin coating of plates and fibers and Bretherton's problem of film deposition in cylindrical channels, albeit now on a double-curved geometry. Here, the balance between gravity, viscosity, surface tension and polymerization rate can yield a constant thickness film. We seek to identify the physical ingredients that govern the final film thickness and its profile. In our experiments using organosilicon, we systematically vary the properties of the fluid, as well as the curvature of the substrate onto which the film is coated, and characterize the final thickness profile of the shells. A reduced model is developed to rationalize the process.

  6. Optimizing vanadium pentoxide thin films and multilayers from dip-coated nanofluid precursors.

    PubMed

    Glynn, Colm; Creedon, Donal; Geaney, Hugh; O'Connell, John; Holmes, Justin D; O'Dwyer, Colm

    2014-02-12

    Using an alkoxide-based precursor, a strategy for producing highly uniform thin films and multilayers of V2O5 is demonstrated using dip coating. Defect-free and smooth films of V2O5 on different surfaces can be deposited from liquid precursors. We show how pinholes are formed due to heterogeneous nucleation during hydrolysis as the precursor forms a nanofluid. Using knowledge of instability formation often found in composite nanofluid films and the influence of cluster formation on the stability of these films, we show how polymer-precursor mixtures provide optimum uniformity and very low surface roughness in amorphous V2O5 and also orthorhombic V2O5 after crystallization by heating. Pinhole and roughness instability formation during the liquid stage of the nanofluid on gold and ITO substrates is suppressed giving a uniform coating. Practically, understanding evolution pathways that involve dewetting processes, nucleation, decomposition, or hydrolysis in complex nanofluids provides a route for improved uniformity of thin films. The method could be extended to improve the consistency in sequential or iterative multilayer deposits of a range of liquid precursors for functional materials and coatings.

  7. Maskless deposition technique for the physical vapor deposition of thin film and multilayer coatings with subnanometer precision and accuracy

    DOEpatents

    Vernon, Stephen P.; Ceglio, Natale M.

    2000-01-01

    The invention is a method for the production of axially symmetric, graded and ungraded thickness thin film and multilayer coatings that avoids the use of apertures or masks to tailor the deposition profile. A motional averaging scheme permits the deposition of uniform thickness coatings independent of the substrate radius. Coating uniformity results from an exact cancellation of substrate radius dependent terms, which occurs when the substrate moves at constant velocity. If the substrate is allowed to accelerate over the source, arbitrary coating profiles can be generated through appropriate selection and control of the substrate center of mass equation of motion. The radial symmetry of the coating profile is an artifact produced by orbiting the substrate about its center of mass; other distributions are obtained by selecting another rotation axis. Consequently there is a direct mapping between the coating thickness and substrate equation of motion which can be used to tailor the coating profile without the use of masks and apertures.

  8. Preparation of metal oxide thin films using coating photolysis process with ArF excimer laser

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Tetsuo; Watanabe, Akio; Imai, Yoji; Niino, Hiroyuki; Yabe, Akira; Yamaguchi, Iwao; Manabe, Takaaki; Kumagai, Toshiya; Mizuta, Susumu

    2000-11-01

    The preparation of metal oxide thin films have been developed using the metalorganic (MO) compounds coating photolysis process with ArF excimer laser irradiation at room temperature. The effect of the starting materials and irradiation method on the product films was investigated by FT-IR, UV, XRD and SEM. It was found that metal acetylacetonates or metal 2-ethylhexanoate was effective as the starting materials. When using metal acetylacetonates as the starting materials, crystallized TiO2, In2O3 and ZrO2 were obtained with ArF laser irradiation at 50 mJ/cm2 at a repetition rate of 5 Hz for 5 min. When using An-acac, Fe, Sn, or In 2-ethylhexanoate as the starting material, a two-step process consisting of both preliminary weak (10mJ/cm2) and sufficiently strong irradiation (50mJ/cm2) was found to be effective for obtaining crystallized ZnO, Fe2O3, SnO2 and In2O3 films. In addition, crystallized complex oxide thin films such as ITO, PbTo3 and PbZrO3 were successfully obtained from the metal acetylacetonates or metal 2-ethylhexanoate using MO coating photolysis process. Patterned metal oxide thin films were also obtained by the ArF laser irradiation through the photomask, followed by leaching with solvents. The crystallization mechanism was discussed from the point of view of the photochemical reaction and photothermal reaction.

  9. Morphology control in thin films of PS:PLA homopolymer blends by dip-coating deposition

    NASA Astrophysics Data System (ADS)

    Vital, Alexane; Vayer, Marylène; Tillocher, Thomas; Dussart, Rémi; Boufnichel, Mohamed; Sinturel, Christophe

    2017-01-01

    In this work, smooth polymer films of PS, PLA and their blends, with thicknesses ranging from 20 nm up to 400 nm and very few defects on the surface were obtained by dip-coating. In contrast to the process of spin-coating which is conventionally used to prepare thin films of polymer blends, we showed that depending on the deposition parameters (withdrawal speed and geometry of the reservoir), various morphologies such as layered films and laterally phase-separated domains could be formed for a given blend/solvent pair, offering much more opportunities compared to the spin-coating process. This diversity of morphologies was explained by considering the superposition of different phenomena such as phase separation process, dewetting and vitrification in which parameters such as the drying time, the compatibility of the polymer/solvent pairs and the affinity of the polymer towards the interfaces were suspected to play a significant role. For that purpose, the process of dip-coating was examined within the capillary and the draining regimes (for low and high withdrawal speed respectively) in order to get a full description of the thickness variation and evaporation rate as a function of the deposition parameters.

  10. Conformal nano-thin modified polyelectrolyte coatings for encapsulation of cells.

    PubMed

    Granicka, L H; Antosiak-Iwańska, M; Godlewska, E; Strawski, M; Szklarczyk, M; Maranowski, B; Kowalewski, C; Wiśniewsk, J

    2011-10-01

    Encapsulation of cells in polymeric shells allows for separation of biological material from produced factors, which may find biotechnological and biomedical applications. Human T-lymphocyte cell line Jurkat as well as rat pancreatic islets were encapsulated using LbL technique within shells of polyelectrolyte modified by incorporation of biotin complexed with avidin to improve cell coating and to create the potential ability to elicit specific biochemical responses. The coating with nano-thin modified shells allowed for maintenance of the evaluated cells' integrity and viability during the 8-day culture. The different PE impact may be observed on different biological materials. The islets exhibited lower mitochondrial activity than the Jurkat cells. Nevertheless, coating of cells with polyelectrolyte modified membrane allowed for functioning of both model cell types: 10 μm leukemia cells or 150 μm islets during the culture. Applied membranes maintained the molecular structure during the culture period. The conclusion is that applied modified membrane conformation may be recommended for coating shells for biomedical purposes.

  11. Behavior of optical thin-film materials and coatings under proton and gamma irradiation.

    PubMed

    Di Sarcina, Ilaria; Grilli, Maria Luisa; Menchini, Francesca; Piegari, Angela; Scaglione, Salvatore; Sytchkova, Anna; Zola, Danilo

    2014-02-01

    Optical materials and coatings are exposed to the flux of energetic particles when used in either space applications or nuclear energy plants. The study of their behavior in such an environment is important to avoid failure of the optical components during their operation. The optical performance of several thin-film materials ((HfO2, Ta2O5, Nb2O5, TiO2, SiO2) and coatings, under irradiation with high-dose gamma rays (5.8 MGy) and exposure to low-energy (60 keV) protons, has been investigated. Some variations of optical properties have been detected in silicon oxide after irradiation, while the other materials are stable in such conditions.

  12. Nanoscratch test — A tool for evaluation of cohesive and adhesive properties of thin films and coatings

    NASA Astrophysics Data System (ADS)

    Tomastik, J.; Ctvrtlik, R.

    2013-04-01

    Thin films and coatings play an essential role in the whole range of applications. The example par excellence are optical thin films that broaden the possibilities of design of optical components. Analogically to other applications of thin films their mechanical properties are very important for their successful applicability and reliability. This becomes especially vital when they are employed in rough service conditions. As thin films on substrates inherently create a compact system the strength of the film-substrate interface is of great importance. Several experimental methods have been developed for qualification and quantification of the mechanical stability of the film-substrate system. In this paper, some brief introduction into the nanoscratch test is introduced. It is currently the most widely used method to evaluate and to test cohesive-adhesive properties of thin films and coatings.

  13. Durability of cutting inserts coated with ion-plated AlTiN thin films

    NASA Astrophysics Data System (ADS)

    Bădănac, A.; Bosoancă, G.; Manole, V.; Bălan, A. C.; Popa, M.; Huşanu, V.

    2015-11-01

    It is known that during the cutting processes, due to the high contact pressures, to the high temperatures, to the relative velocities and shocks between the contact surfaces tool-part can lead to a wear more or less pronounced of the metal carbide cutting inserts. Are known numerous coating processes regarding the increasing the durability of the used cutting inserts, namely by deposition of different materials, having protection role for the cutting inserts locating and clearance surfaces, methods as: vapor chemical deposition at low pressure, pulverization, cathodic arc ion plating, vacuum thermal evaporation and condensation from the vapor phase. Researches carried out by authors in this paper, have followed the deposition of aluminum and titanium materials (AlTiN) in thin layers, on surface of some metal carbide cutting inserts profiled. The depositions of AlTiN materials are new coatings which consists in deposition of the compound solid of AlTiN in the form of vapor in thin layers on different tools or/and the cutting inserts. In the purpose of increasing the cutting inserts durability, they used deposition method by cathodic arc ion plating in vacuum. The authors chose this method due to its advantages, which can be enumerate: the relatively low costs of the equipment, the simplicity in operation, the possibility to be used also to realize researches and industrial installations. As a result of using this method was found a considerable increase of the durability for the metal carbide cutting inserts coated with AlTiN materials, used in the cutting process compared to cutting inserts which were not coated.

  14. Enhancement of the photoprotection and nanomechanical properties of polycarbonate by deposition of thin ceramic coatings

    SciTech Connect

    Mailhot, B.; Rivaton, A.; Gardette, J.-L.; Moustaghfir, A.; Tomasella, E.; Jacquet, M.; Ma, X.-G.; Komvopoulos, K.

    2006-05-15

    The chemical reactions resulting from ultraviolet radiation produce discoloration and significant changes in the surface properties of polycarbonate (PC). To prevent photon absorption from irradiation and oxygen diffusion and to enhance the surface nanomechanical properties of PC, thin ceramic coatings of ZnO and Al{sub 2}O{sub 3} (both single- and multi-layer) were deposited on bulk PC by radio-frequency magnetron sputtering. The samples were irradiated at wavelengths greater than 300 nm, representative of outdoor conditions. Despite the effectiveness of ZnO to protect PC from irradiation damage, photocatalytic oxidation at the PC/ZnO interface was the limiting factor. To overcome this deficiency, a thin Al{sub 2}O{sub 3} coating was used both as intermediate and top layer because of its higher hardness and wear resistance than ZnO. Therefore, PC/Al{sub 2}O{sub 3}/ZnO, PC/ZnO/Al{sub 2}O{sub 3}, and PC/Al{sub 2}O{sub 3}/ZnO/Al{sub 2}O{sub 3} layered media were fabricated and their photodegradation properties were examined by infrared and ultraviolet-visible spectroscopy. It was found that the photocatalytic activity at the PC/ZnO interface was reduced in the presence of the intermediate Al{sub 2}O{sub 3} layer that limited the oxygen permeability. Nanomechanical experiments performed with a surface force apparatus revealed that the previous coating systems enhanced both the surface nanohardness and the elastic modulus and reduced the coefficient of friction in the order of ZnO, Al{sub 2}O{sub 3}, and Al{sub 2}O{sub 3}/ZnO/Al{sub 2}O{sub 3}. Although irradiation increased the nanohardness and the elastic modulus of PC, the irradiation effect on the surface mechanical properties of ceramic-coated PC was secondary.

  15. Enhanced structural color generation in aluminum metamaterials coated with a thin polymer layer.

    PubMed

    Cheng, Fei; Yang, Xiaodong; Rosenmann, Daniel; Stan, Liliana; Czaplewski, David; Gao, Jie

    2015-09-21

    A high-resolution and angle-insensitive structural color generation platform is demonstrated based on triple-layer aluminum-silica-aluminum metamaterials supporting surface plasmon resonances tunable across the entire visible spectrum. The color performances of the fabricated aluminum metamaterials can be strongly enhanced by coating a thin transparent polymer layer on top. The results show that the presence of the polymer layer induces a better impedance matching for the plasmonic resonances to the free space so that strong light absorption can be obtained, leading to the generation of pure colors in cyan, magenta, yellow and black (CMYK) with high color saturation.

  16. Time domain scattering and radar cross section calculations for a thin, coated perfectly conducting plate

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Beggs, John H.

    1991-01-01

    Radar cross section (RCS) calculations for flat, perfectly conducting plates are readily available through the use of conventional frequency domain techniques such as the Method of Moments (MOM). However, if the plate is covered with a dielectric material that is relatively thick in comparison with the wavelength in the material, these frequency domain techniques become increasingly difficult to apply. We present the application of the Finite Difference Time Domain (FDTD) Technique to the problem of electromagnetic scattering and RCS calculations from a thin, perfectly conducting plate that is coated with a thick layer of lossless dielectric material. Both time domain and RCS calculations are presented and disclosed.

  17. Time domain scattering and radar cross section calculations for a thin, coated perfectly conducting plate

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Beggs, John H.

    1991-01-01

    Radar cross section (RCS) calculations for flat, perfectly conducting plates are readily available through the use of conventional frequency domain techniques such as the Method of Moments (MOM). However, if the plate is covered with a dielectric material that is relatively thick in comparison with the wavelength in the material, these frequency domain techniques become increasingly difficult to apply. The application is presented of the Finite Difference Time Domain (FDTD) technique to the problem of electromagnetic scattering and RCS calculations from a thin, perfectly conducting plate that is coated with a thick layer of lossless dielectric material. Both time domain and RCS calculations are presented and discussed.

  18. Fabrication and characterization of high mobility spin-coated zinc oxide thin film transistors

    NASA Astrophysics Data System (ADS)

    Singh, Shaivalini; Chakrabarti, P.

    2012-10-01

    A ZnO based thin film transistor (TFT) with bottom-gate configuration and SiO2 as insulating layer has been fabricated and characterized. The ZnO thin film was prepared by spin coating the sol-gel solution on the p-type Si wafers. The optical and structural properties of ZnO films were investigated using UV measurements and scanning electron microscope (SEM). The result of UV-visible study confirms that the films have a good absorbance in UV region and relatively low absorbance in the visible region. The TFT exhibited an off-current of 2.5×10-7 A. The values of field effect channel mobility and on/off current ratio extracted for the device, measured 11 cm2/V.s and ~102 respectively. The value of threshold voltage was found to be 1.3 V.

  19. EUV reflectometry for thickness and density determination of thin film coatings

    NASA Astrophysics Data System (ADS)

    Döring, S.; Hertlein, F.; Bayer, A.; Mann, K.

    2012-06-01

    An EUV reflectometer for the analysis of surfaces and thin films regarding refractive index, surface roughness, and mass density at the wavelength of 12.98 nm was developed. The setup uses a laser produced plasma source with an oxygen gas puff target for the generation of narrow-band EUV radiation and a flexible Kirkpatrick-Baez optics for focusing. We present EUV reflectometry (EUVR) measurements conducted on a series of carbon thin films to determine thickness and mass density of the coatings. In case of the thickness measurements results are compared to data obtained from nondestructive standard methods, i.e., grazing incidence X-ray reflectometry and spectroscopic ellipsometry. In addition, we propose a method to deduce the mass density of a sample directly from the fitted index of refraction obtained from EUVR measurements.

  20. Spectroscopic studies of UV irradiated erythrosine B thin films prepared by spin coating technique.

    PubMed

    Zeyada, H M; El-Mallah, H M; Atwee, T; El-Damhogi, D G

    2017-05-15

    The spectroscopic studies of erythrosine B thin films manufactured by the spin coating technique have been presented. The spectra of infrared absorption allow characterization of vibrational modes for erythrosine B in powder form, pristine and UV irradiated thin films. The absorption spectra recorded in UV-vis-NIR for pristine films of erythrosine B display two main bands. UV irradiation on erythrosine B films decreased absorbance over the spectra. Indirect allowed transition with optical energy gap of 2.57eV is observed in pristine films. UV irradiation introduced structural defects and decreased optical band gap. Some of the optical absorption parameters and their relation to UV irradiation times, namely molar extinction coefficient (ε), electronic dipole strength (q(2)), and oscillator strength (f), of the principal optical transitions have also been evaluated.

  1. Characterization and simulation on antireflective coating of amorphous silicon oxide thin films with gradient refractive index

    NASA Astrophysics Data System (ADS)

    Huang, Lu; Jin, Qi; Qu, Xingling; Jin, Jing; Jiang, Chaochao; Yang, Weiguang; Wang, Linjun; Shi, Weimin

    2016-08-01

    The optical reflective properties of silicon oxide (SixOy) thin films with gradient refractive index are studied both theoretically and experimentally. The thin films are widely used in photovoltaic as antireflective coatings (ARCs). An effective finite difference time domain (FDTD) model is built to find the optimized reflection spectra corresponding to structure of SixOy ARCs with gradient refractive index. Based on the simulation analysis, it shows the variation of reflection spectra with gradient refractive index distribution. The gradient refractive index of SixOy ARCs can be obtained in adjustment of SiH4 to N2O ratio by plasma-enhanced chemical vapor deposition (PECVD) system. The optimized reflection spectra measured by UV-visible spectroscopy confirms to agree well with that simulated by FDTD method.

  2. Synthesis and characterization of nanocomposite polymer blend electrolyte thin films by spin-coating method

    NASA Astrophysics Data System (ADS)

    Chapi, Sharanappa; Niranjana, M.; Devendrappa, H.

    2016-05-01

    Solid Polymer blend electrolytes based on Polyethylene oxide (PEO) and poly vinyl pyrrolidone (PVP) complexed with zinc oxide nanoparticles (ZnO NPs; Synthesized by Co-precipitation method) thin films have prepared at a different weight percent using the spin-coating method. The complexation of the NPs with the polymer blend was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The variation in film morphology was examined by polarized optical micrographs (POMs). The thermal behavior of blends was investigated under non-isothermal conditions by differential thermal analyses (DTA). A single glass transition temperature for each blend was observed, which supports the existence of compatibility of such system. The obtained results represent that the ternary based thin films are prominent materials for battery and optoelectronic device applications.

  3. Differential Adhesive and Bioactive Properties of the Polymeric Surface Coated with Graphene Oxide Thin Film.

    PubMed

    Thampi, Sudhin; Nandkumar, A Maya; Muthuvijayan, Vignesh; Parameswaran, Ramesh

    2017-02-08

    Surface engineering of implantable devices involving polymeric biomaterials has become an essential aspect for medical implants. A surface enhancement technique can provide an array of unique surface properties that improve its biocompatibility and functionality as an implant. Polyurethane-based implants that have found extensively acclaimed usage as an implant in biomedical applications, especially in the area of cardiovascular devices, still lack any mechanism to ward off bacterial or platelet adhesion. To bring out such a defense mechanism we are proposing a surface modification technique. Graphene oxide (GO) in very thin film form was wrapped onto the electrospun fibroporous polycarbonate urethane (PCU) membrane (GOPCU) by a simple method of electrospraying. In the present study, we have developed a simple single-step method for coating a polymeric substrate with a thin GO film and evaluated the novel antiadhesive activity of these films. SEM micrographs after coating showed the presence of very thin GO films over the PCU membrane. On the GOPCU surface, the contact angle was shifted by ∼30°, making the hydrophobic PCU surface slightly hydrophilic, while Raman spectral characterization and mapping showed the presence and distribution of GO over 75% of the membrane. A reduced platelet adhesion on the GOPCU surface was observed; meanwhile, bacterial adhesion also got reduced by 85% for Staphylococcus aureus (Gram positive, cocci) and 64% for Pseudomonas aeruginosa (Gram negative, bacilli). A cell adhesion study conducted using mammalian fibroblast cells projected its proliferation percentage in a MTT assay, with 82% cell survival on PCU and 86% on GOPCU after 24 h culture, while a study for an extended period of 72 h showed 87% of survival on PCU and 88% on GOPCU. This plethora of functionalities by a simple modification technique makes thin GO films a self-sufficient surface engineering material for future biomedical applications.

  4. Effect of Doping on beta-Tricalcium Phosphate Bioresorbable Bulk Material and Thin Film Coatings

    NASA Astrophysics Data System (ADS)

    Abdalla, Suhaila

    Magnesium has emerged as a revolutionary biodegradable metal for use as an orthopedic material, it has several advantages over the current metallic materials in use, including eliminating the effects of stress shielding, improving biocompatibility and inhibiting degradation rates, thus removing the requirement of a second surgery for implant removal. Due to the rapid degradation of magnesium, it is necessary to control the corrosion rates of the materials to match the rates of bone healing. This dissertation reports on the effect of doping on the properties of beta-tricalcium phosphate (beta-TCP). It also reports on its application as a thin film coating on magnesium alloys for implant applications. Adding various dopants to beta-TCP significantly influences critical properties. In this study, discs were fabricated in two compositions: (i) undoped beta-TCP, (ii) beta-TCP doped with 1.0 wt % MgO, 0.5 wt % ZnO, and 1.0 wt % TiO2. Films were fabricated from these compositions using the pulsed laser deposition (PLD) technique. These coatings were then characterized for corrosive, hardness, and cytocompatibility. The XRD patterns of the coating confirm the amorphous nature of the films. The presence of the metal oxides in beta-TCP improved ceramic densification. The application of these doped coatings was also found to increase the hardness by 88 %, the modulus of elasticity by 66 %, and improve corrosion resistance of the magnesium alloy substrate; with a 2.4 % improvement in Ecorr and 95 % decrease in icorr. Cell viability was studied using an osteoblast precursor cell line MC3T3-E1 to assure that the biocompatibility of these ceramics was not altered due to the dopants. Long-term biodegradation studies were conducted by measuring weight change and surface microstructure as a function of time in simulated body fluid. The results suggest that these coatings could be used for bioresorbable implants with improved corrosion resistance and increased hardness.

  5. Enhanced Field Emission from Vertically Oriented Graphene by Thin Solid Film Coatings

    NASA Astrophysics Data System (ADS)

    Bagge-Hansen, Michael

    Recent progress and a coordinated national research program have brought considerable effort to bear on the synthesis and application of carbon nanostructures for field emission. At the College of William and Mary, we have developed field emission arrays of vertically oriented graphene (carbon nanosheets, CNS) that have demonstrated promising cathode performance, delivering emission current densities up to 2 mA/mm2 and cathode lifetime >800 hours. The work function (φ) of CNS and other carbonaceous cathode materials has been reported to be φ˜4.5-5.1 eV. The application of low work function thin films can achieve several orders of magnitude enhancement of field emission. Initially, the intrinsic CNS field emission was studied. The mean height of the CNS was observed to decrease as a function of operating time at a rate of ˜0.05 nm/h (I 1˜40 muA/mm2). The erosion mechanism was studied using a unique UHV diode design which allowed line-of-site assessment from the field emission region in the diode to the ion source of a mass spectrometer. The erosion of CNS was found to occur by impingement of hyperthermal H and O neutrals and ions generated at the surface oxide complex of the Cu anode by electron stimulated desorption. Techniques for minimizing this erosion are presented. The Mo2C (φ˜3.7 eV) beading on CNS at previously reported carbide formation temperatures of ˜800°C was circumvented by physical vapor deposition of Mo and vacuum annealing at ˜300°C which resulted in a conformal Mo2C coating and stable field emission of 1˜50 muA/mm2. For a given applied field, the emission current was >102 greater than uncoated CNS. ThO2 thin film coatings were presumed to be even more promising because of a reported work function of φ ˜2.6 eV. The fundamental behavior of the initial oxidation of polycrystalline Th was studied in UHV (p<1x10-11 Torr), followed by studies of thin film coatings on Ir and thermionic emission characteristics. Although a work function of 3

  6. Note: Automatic layer-by-layer spraying system for functional thin film coatings

    NASA Astrophysics Data System (ADS)

    Seo, Seongmin; Lee, Sangmin; Park, Yong Tae

    2016-03-01

    In this study, we have constructed an automatic spray machine for producing polyelectrolyte multilayer films containing various functional materials on wide substrates via the layer-by-layer (LbL) assembly technique. The proposed machine exhibits advantages in terms of automation, process speed, and versatility. Furthermore, it has several features that allow a fully automated spraying operation, such as various two-dimensional spraying paths, control of the flow rate and operating speed, air-assist fan-shaped twin-fluid nozzles, and an optical display. The robot uniformly sprays aqueous mixtures containing complementary (e.g., oppositely charged, capable of hydrogen bonding, or capable of covalent bonding) species onto a large-area substrate. Between each deposition of opposite species, samples are spray-rinsed with deionized water and blow-dried with air. The spraying, rinsing, and drying areas and times are adjustable by a computer program. Twenty-bilayer flame-retardant thin films were prepared in order to compare the performance of the spray-assisted LbL assembly with a sample produced by conventional dipping. The spray-coated film exhibited a reduction of afterglow time in vertical flame tests, indicating that the spray-LbL technique is a simple method to produce functional thin film coatings.

  7. Plasmonic enhancement of thin-film solar cells using gold-black coatings

    SciTech Connect

    Fredricksen, Christopher J.; Panjwani, D. R.; Arnold, J. P.; Figueiredo, P. N.; Rezaie, F. K.; Colwell, J. E.; Baillie, K.; Peppernick, Samuel J.; Joly, Alan G.; Beck, Kenneth M.; Hess, Wayne P.; Peale, Robert E.

    2011-08-11

    Coatings of conducting gold-black nano-structures on commercial thin-film amorphous-silicon solar cells enhance the short-circuit current by 20% over a broad spectrum from 400 to 800 nm wavelength. The efficiency, i.e. the ratio of the maximum electrical output power to the incident solar power, is found to increase 7% for initial un-optimized coatings. Metal blacks are produced cheaply and quickly in a low-vacuum process requiring no lithographic patterning. The inherently broad particle-size distribution is responsible for the broad spectrum enhancement in comparison to what has been reported for mono-disperse lithographically deposited or self-assembled metal nano-particles. Photoemission electron microscopy reveals the spatial-spectral distribution of hot-spots for plasmon resonances, where scattering of normally-incident solar flux into the plane increases the effective optical path in the thin film to enhance light harvesting. Efficiency enhancement is correlated with percent coverage and particle size distribution, which are determined from histogram and wavelet analysis of scanning electron microscopy images. Electrodynamic simulations reveal how the gold-black particles scatter the radiation and locally enhance the field strength.

  8. Surface chemistry of coated lithium manganese nickel oxide thin film cathodes studied by XPS

    SciTech Connect

    Baggetto, Loic; Dudney, Nancy J; Veith, Gabriel M

    2013-01-01

    The effect of coating high voltage LiMn1.5Ni0.5O4 spinel cathode thin films with three metal oxide thin layers is discussed. The changes in surface chemistry of the electrodes are measured by X-ray photoelectron spectroscopy. ZnO is found to decompose during the first charge whereas Al2O3 and ZrO2 are stable for more than 100 cycles. ZrO2, however, importantly limits the available Li storage capacity of the electrochemical reaction due to poorer kinetics. Al2O3 offers the best results in term of capacity retention. Upon cycling, the evidence of a signal at 75.4 eV in the Al2p binding energy spectrum indicates the partial conversion of Al2O3 into Al2O2F2. Moreover, the continuous formation of PEO , esters and LixPOyFz compounds on the surface of the electrodes is found for all coating materials.

  9. Morphology, microstructure, stress and damage properties of thin film coatings for the LCLS x-ray mirrors

    SciTech Connect

    Soufli, R; Baker, S L; Robinson, J C; Gullikson, E M; McCarville, T J; Pivovaroff, M J; Stefan, P; Hau-Riege, S P; Bionta, R

    2009-04-23

    The development and properties of reflective coatings for the x-ray offset mirror systems of the Linac Coherent Light Source (LCLS) free-electron laser (FEL) are discussed in this manuscript. The uniquely high instantaneous dose of the LCLS FEL beam translates to strict limits in terms of materials choice, thus leading to an x-ray mirror design consisting of a reflective coating deposited on a silicon substrate. Coherent wavefront preservation requirements for these mirrors result in stringent surface figure and finish specifications. DC-magnetron sputtered B{sub 4}C and SiC thin film coatings with optimized stress, roughness and figure properties for the LCLS x-ray mirrors are presented. The evolution of microstructure, morphology, and stress of these thin films versus deposition conditions is discussed. Experimental results on the performance of these coatings with respect to FEL damage are also presented.

  10. "Black art" of thin film coating: why this term is used and how to change this mind-set

    NASA Astrophysics Data System (ADS)

    Jansen, S. W.; Hatchett, Philip J.; Hughes, S. W.; Jones, D. Paul; Gibson, Desmond R.

    1996-08-01

    The words 'black art' are often associated with thin film coating. We cast our spell on a coating plant and, as if by magic, the glass is transformed. The problem is that the spell sometimes fails and we end up with stone instead of gold. When we ask the magician (coating technician) what went wrong, the answer is all too often 'I did it exactly the same way as the last time'. This creates the perception that thin film coating is a black art because clearly something different did happen. What we don't know is which of the multitude of parameters went wrong, and often the only way to find out is through a process of elimination. This is very costly to the industry both in monetary value and image.

  11. Carbonaceous thin film coating with Fe-N4 site for enhancement of dioxovanadium ion reduction

    NASA Astrophysics Data System (ADS)

    Maruyama, Jun; Hasegawa, Takahiro; Iwasaki, Satoshi; Fukuhara, Tomoko; Orikasa, Yuki; Uchimoto, Yoshiharu

    2016-08-01

    It has been found that carbonaceous materials containing a transition metal coordinated by 4 nitrogens in the square-planar configuration (metal-N4 site) on the surface possessed a catalytic activity for various electrochemical reactions related to energy conversion and storage; i.e., oxygen reduction, hydrogen evolution, and quite recently, the electrode reactions in vanadium redox flow batteries (VRFB). The catalyst for the VRFB positive electrode discharge reaction, i.e., the dioxovanadium ion reduction, was formed by coating the surface of cup-stack carbon nanotubes with a carbonaceous thin film with the Fe-N4 site generated by the sublimation, deposition, and pyrolysis of iron phthalocyanine. In this study, the influence of the physical properties of the catalyst on the electrochemical reactions was investigated to optimize the coating. With an increase in the coating, the specific surface area increased, whereas the pore size decreased. The surface Fe concentration was increased in spite of the Fe aggregation inside the carbon matrix. The catalytic activity enhancement was achieved due to the increase in the specific surface area and the surface Fe concentration, but was lowered due to the decrease in the pore size, which was disadvantageous for the penetration of the electrolyte and the mass transfer.

  12. Surface characterization of an energetic material, pentaerythritoltetranitrate (PETN), having a thin coating achieved through a starved addition microencapsulation technique

    SciTech Connect

    Worley, C.M.

    1986-05-07

    The objective of this research was to: (1) determine the nature of a thin coating on an explosive material which was applied using a starved addition microencapsulation technique, (2) understand the coating/crystal bond, and (3) investigate the wettability/adhesion of plastic/solvent combinations using the coating process. The coating used in this work was a Firestone Plastic Company copolymer (FPC-461) of vinylchloride/trifluorochloroethylene in a 1.5/1.0 weight ratio. The energetic explosive examined was pentaerythritoltetranitrate (PETN). The coating process used was starved addition followed by a solvent evaporation technique. Surface analytical studies, completed for characterization of the coating process, show (1) evidence that the polymer coating is present, but not continuous, over the surface of PETN; (2) the average thickness of the polymer coating is between 16-32 A and greater than 44 A, respectively, for 0.5 and 20 wt % coated PETN; (3) no changes in surface chemistry of the polymer or the explosive material following microencapsulation; and (4) the presence of explosive material on the surface of 0.5 wt % FPC-461 coated explosives. 5 refs., 15 figs., 6 tabs.

  13. Theory and practical considerations of multilayer dielectric thin-film stacks in Ag-coated hollow waveguides.

    PubMed

    Bledt, Carlos M; Melzer, Jeffrey E; Harrington, James A

    2014-02-01

    This analysis explores the theory and design of dielectric multilayer reflection-enhancing thin film stacks based on high and low refractive index alternating layers of cadmium sulfide (CdS) and lead sulfide (PbS) on silver (Ag)-coated hollow glass waveguides (HGWs) for low loss transmission at midinfrared wavelengths. The fundamentals for determining propagation losses in such multilayer thin-film-coated Ag hollow waveguides is thoroughly discussed, and forms the basis for further theoretical analysis presented in this study. The effects on propagation loss resulting from several key parameters of these multilayer thin film stacks is further explored in order to bridge the gap between results predicted through calculation under ideal conditions and deviations from such ideal models that often arise in practice. In particular, the effects on loss due to the number of dielectric thin film layers deposited, deviation from ideal individual layer thicknesses, and surface roughness related scattering losses are presented and thoroughly investigated. Through such extensive theoretical analysis the level of understanding of the underlying loss mechanisms of multilayer thin-film Ag-coated HGWs is greatly advanced, considerably increasing the potential practical development of next-generation ultralow-loss mid-IR Ag/multilayer dielectric-coated HGWs.

  14. Boosting the Transparency of Thin Layers by Coatings of Opposing Susceptibility: How Metals Help See Through Dielectrics

    PubMed Central

    Shakhs, Mohammed Al; Augusto, Lucian; Markley, Loïc; Chau, Kenneth J.

    2016-01-01

    We propose a hypothesis that a very thin layer can be made more transparent by adding a thin coating with susceptibility of opposing sign. Two experimental tests backed by a theoretical model support this hypothesis. First, we show that the visible and near-infrared transmission through a semi-transparent silver film can be enhanced by up to ~70% and spectrally tailored depending on the type and thickness of the dielectric coating. Material types explored as dielectric coating layers include conventional metal oxides (titanium dioxide) and lesser-explored elemental semiconductors (undoped silicon, p-type silicon, and germanium). Second, and more surprisingly, we show that coating a 50-nm-thick silicon nitride membrane with a 10-nm-thick silver layer can modestly enhance the transmission by up to 6 ± 1% in the blue part of the spectrum. Transmission enhancements are observed for three silver-coated membranes in different configurations. Thinner silver coatings are theoretically capable of enhancement factors greater than 10%, but implementation is restricted by challenges in making smooth and continuous silver films below 10 nm in thickness. This study is important because it is the first demonstration of reciprocity with respect to the transmission enhancements achieved by combining thin metallic and dielectric layers. PMID:26860979

  15. Optimization of the antireflection coating of thin epitaxial crystalline silicon solar cells

    DOE PAGES

    Selj, Josefine K.; Young, David; Grover, Sachit

    2015-08-28

    In this study we use an effective weighting function to include the internal quantum efficiency (IQE) and the effective thickness, Te, of the active cell layer in the optical modeling of the antireflection coating (ARC) of very thin crystalline silicon solar cells. The spectrum transmitted through the ARC is hence optimized for efficient use in the given cell structure and the solar cell performance can be improved. For a 2-μm thick crystalline silicon heterojunction solar cell the optimal thickness of the Indium Tin Oxide (ITO) ARC is reduced by ~8 nm when IQE data and effective thickness are taken intomore » account compared to the standard ARC optimization, using the AM1.5 spectrum only. The reduced ARC thickness will shift the reflectance minima towards shorter wavelengths and hence better match the absorption of very thin cells, where the short wavelength range of the spectrum is relatively more important than the long, weakly absorbed wavelengths. For this cell, we find that the optimal thickness of the ITO starts at 63 nm for very thin (1 μm) active Si layer and then increase with increasing Te until it saturates at 71 nm for Te > 30 μm.« less

  16. Optimization of the antireflection coating of thin epitaxial crystalline silicon solar cells

    SciTech Connect

    Selj, Josefine K.; Young, David; Grover, Sachit

    2015-08-28

    In this study we use an effective weighting function to include the internal quantum efficiency (IQE) and the effective thickness, Te, of the active cell layer in the optical modeling of the antireflection coating (ARC) of very thin crystalline silicon solar cells. The spectrum transmitted through the ARC is hence optimized for efficient use in the given cell structure and the solar cell performance can be improved. For a 2-μm thick crystalline silicon heterojunction solar cell the optimal thickness of the Indium Tin Oxide (ITO) ARC is reduced by ~8 nm when IQE data and effective thickness are taken into account compared to the standard ARC optimization, using the AM1.5 spectrum only. The reduced ARC thickness will shift the reflectance minima towards shorter wavelengths and hence better match the absorption of very thin cells, where the short wavelength range of the spectrum is relatively more important than the long, weakly absorbed wavelengths. For this cell, we find that the optimal thickness of the ITO starts at 63 nm for very thin (1 μm) active Si layer and then increase with increasing Te until it saturates at 71 nm for Te > 30 μm.

  17. Growth of YBCO Thin Films on TiN(001) and CeO2-Coated TiN Surfaces

    DTIC Science & Technology

    2012-02-01

    substrates. Thin CeO2 (~200 nm thick) and YBCO (~300 nm thick) layers were grown on TiN-coated MgO substrates, using pulsed laser deposition. While YBCO ...and YBCO (300 nm thick) layers were grown on TiN-coated MgO substrates, using pulsed laser deposition. While YBCO grown directly on TiN was of poor...grown on the TiN-coated MgO and then an 300 nm thick YBCO layers was subsequently depos- ited. For other samples, YBCO deposition directly on the

  18. Thermal conductivity of ZrO2-4mol%Y2O3 thin coatings by pulsed thermal imaging method

    SciTech Connect

    Jang, Byung-Koog; Sun, Jiangang; Kim, Seongwon; Oh, Yoon-Suk; Lee, Sung-Min; Kim, Hyung-Tae

    2015-12-01

    Thin ZrO2-4mol% Y2O3 coatings were deposited onto ZrO2 substrates by electron beam-physical vapor deposition. The coated samples revealed a feather-like columnar microstructure. The main phase of the ZrO2-4mol% Y2O3 coatings was the tetragonal phase. To evaluate the influence of the coating’s thickness on the thermal conductivity of thin ZrO2-4mol% Y2O3 coatings, the pulsed thermal imaging method was employed to obtain the thermal conductivity of the coating layer in the two-layer (coating and substrate) samples with thickness between 56 and 337 micrometers. The thermal conductivity of the coating layer was successfully evaluated and compared well with those obtained by the laser flash method for similar coatings. The thermal conductivity of coatings shows an increasing tendency with an increase in the coating’s thickness.

  19. Strong thin membrane structure for use as solar sail comprising substrate with reflective coating on one surface and an infra red emissivity increasing coating on the other surface

    NASA Technical Reports Server (NTRS)

    Frazer, Robert E. (Inventor)

    1982-01-01

    Production of strong lightweight membrane structure by applying a thin reflective coating such as aluminum to a rotating cylinder, applying a mesh material such as nylon over the aluminum coating, coating the mesh overlying the aluminum with a polymerizing material such as a para-xylylene monomer gas to polymerize as a film bound to the mesh and the aluminum, and applying an emissivity increasing material such as chromium and silicon monoxide to the polymer film to disperse such material colloidally into the growing polymer film, or applying such material to the final polymer film, and removing the resulting membrane structure from the cylinder. Alternatively, such membrane structure can be formed by etching a substrate in the form of an organic film such as a polyimide, or a metal foil, to remove material from the substrate and reduce its thickness, applying a thin reflective coating such as aluminum on one side of the substrate and applying an emissivity increasing coating such as chromium and silicon monoxide on the reverse side of the substrate.

  20. Thermal stability of piezoelectric properties and infrared sensor performance of spin-coated polyurea thin films

    NASA Astrophysics Data System (ADS)

    Morimoto, Masahiro; Koshiba, Yasuko; Misaki, Masahiro; Ishida, Kenji

    2015-10-01

    We have investigated the temperature dependence of the piezoelectric coefficients and infrared sensor performance of spin-coated thin films of polyundecylurea (PUA11). The piezoelectric coefficients of the PUA11 films remained constant at temperatures above 180 °C and these films demonstrated thermal resistance superior to those of poly(vinylidene fluoride/trifluoroethylene) [P(VDF/TrFE)] films. The infrared sensor performance of the PUA11 films was measured after annealing at 125 °C for 500 h and was found to have retained 84% of its preannealing level. The thermal stability of the PUA11 films was higher than that of the P(VDF/TrFE) films; moreover, PUA11 is also expected to have superior electrothermal stability.

  1. Studies on VOx thin films deposited over Si3N4 coated Si substrates

    NASA Astrophysics Data System (ADS)

    Raj, P. Deepak; Gupta, Sudha; Sridharan, M.

    2015-06-01

    Vanadium oxide (VOx) thin films were deposited on to the silicon nitride (Si3N4) coated silicon (Si) substrate using reactive direct current magnetron sputtering at different substrate temperatures (Ts). The deposited films were characterized for their structural, morphological, optical and electrical properties. The average grain size of the deposited films was in the range of 95 to 178 nm and the strain varied from 0.071 to 0.054 %. The optical bandgap values of the films were evaluated using UV-Vis spectroscopy and lies in the range of 2.46 to 3.88 eV. The temperature coefficient of resistance (TCR) for the film deposited at 125 °C was -1.23%/°C with the sheet resistivity of 2.7 Ω.cm.

  2. Structural and electrical properties of sol-gel spin coated indium doped cadmium oxide thin films

    SciTech Connect

    Rajammal, R.; Savarimuthu, E. Arumugam, S.

    2014-04-24

    The indium doped CdO thin films have been prepared by the sol-gel spin coating technique and the influence of indium doping concentration on the structural and electrical properties of the deposited films has been investigated. The indium doping concentration in the solution has been varied from 0-10 wt% insteps of 2wt%. A indium doping concentration of 6wt% has been found to be optimum for preparing the films and at this stage a minimum resistivity of 5.92×10{sup −4}Ω cm and a maximum carrier concentration of 1.20×10{sup 20}cm{sup −3} have been realized.

  3. Preparation of a Functionally Graded Fluoropolymer Thin Film and Its Application to Antireflective Coating

    NASA Astrophysics Data System (ADS)

    Senda, Kazuo; Matsuda, Tsuyoshi; Kawanishi, Takumi; Tanaka, Kuniaki; Usui, Hiroaki

    2013-05-01

    Fluoropolymer thin films were prepared by the ion-assisted vapor deposition polymerization (IAD) of 2-(perfluorohexyl) ethylacrylate (Rf-6) under Ar ion irradiation. The ion acceleration voltage Va largely affected the film characteristics. With increasing Va, the adhesion strength between the film and the substrate improved, while the surface energy and the refractive index increased. To attain a high adhesion strength, a low surface energy, and a low optical reflectivity simultaneously, a functionally graded film was prepared by varying Va from 300 to 0 V continually in the course of film growth. As a consequence, an antireflective coating with good adhesion and low surface energy was obtained. The optical reflectivity of a glass substrate was reduced from 4.9 to 0.55% at a wavelength of 400 nm by depositing a 100-nm-thick single-layer functionally graded fluoropolymer film. The surface energy of this film was 8.5 mJ/m2.

  4. Plasma polymerized thin coating as a protective layer of carbon nanotubes grafted on carbon fibers

    NASA Astrophysics Data System (ADS)

    Einig, A.; Rumeau, P.; Desrousseaux, S.; Magga, Y.; Bai, J. B.

    2013-04-01

    Nanoparticles addition is widely studied to improve properties of carbon fiber reinforced composites. Here, hybrid carbon fiber results from grafting of carbon nanotubes (CNT) by Chemical Vapor Deposition (CVD) on the carbon fiber for mechanical reinforcement and conductive properties. Both tows and woven fabrics made of the hybrid fibers are added to the matrix for composite processing. However handling hybrid fibers may induce unwilling health risk due to eventual CNT release and a protective layer is required. A thin coating layer is deposited homogeneously by low pressure plasma polymerization of an organic monomer without modifying the morphology and the organization of grafted CNTs. The polymeric layer effect on the electrical behavior of hybrid fiber is assessed by conductivity measurements. Its influence on the mechanical properties is also studied regarding the interface adhesion between fiber and matrix. The protective role of layer is demonstrated by means of friction constraints applied to the hybrid fiber.

  5. Ellipsometry study on gold-nanoparticle-coated gold thin film for biosensing application

    PubMed Central

    Moirangthem, Rakesh Singh; Chang, Yia-Chung; Wei, Pei-Kuen

    2011-01-01

    The amplified plasmonic response from various distributions of gold nanoparticles (AuNPs) coated on top of gold thin film was studied via ellipsometry under total internal reflection mode. The surface plasmon resonance dip can be tuned from the visible to near infrared by simply varying the AuNP concentration. Theoretical modeling based on effective medium theory with a multi-slice model has been employed to fit the experimental results. Additionally, this experimental tool has been further extended to study bio-molecular interactions with metal surfaces as well as in studying protein-protein interaction without any labeling. Hence, this technique could provide a non-destructive way of designing tunable label-free optical biosensors with very high sensitivity. PMID:21991549

  6. Dip coated nanocrystalline CdZnS thin films for solar cell application

    NASA Astrophysics Data System (ADS)

    Dongre, J. K.; Chaturvedi, Mahim; Patil, Yuvraj; Sharma, Sandhya; Jain, U. K.

    2015-07-01

    Nanocrystalline cadmium sulfide (CdS) and zinc cadmium sulfide (ZnCdS) thin films have been grown via simple and low cost dip coating technique. The prepared films are characterized by X-ray diffraction (XRD), atomic force microscopic (AFM) and UV-VIS spectrophotometer techniques to reveal their structural, morphological and optical properties. XRD shows that both samples grown have zinc blende structure. The grain size is calculated as 6.2 and 8 nm using Scherrer's formula. The band gap value of CdS and CdZnS film is estimated to be 2.58 and 2.69 eV respectively by UV-vis spectroscopy. Photoelectrochemical (PEC) investigations are carried out using cell configuration as n-CdZnS/(1M NaOH + 1M Na2S + 1M S)/C. The photovoltaic output characteristic is used to calculate fill-factor (FF) and solar conversion efficiency (η).

  7. Secondary electron yield measurements from thin surface coatings for NLC electron cloud reduction

    SciTech Connect

    Le Pimpec, F

    2004-05-17

    In the beam pipe of the positron damping ring of the Next Linear Collider, electrons will be created by beam interaction with the surrounding vacuum chamber wall and give rise to an electron cloud. Several solutions are possible for avoiding the electron cloud, without changing the beam bunch structure or the diameter of the vacuum chamber. Some of the currently available solutions for preventing this spurious electron load include reducing residual gas ionization by the beam, minimizing beam photon-induced electron production, and lowering the secondary electron yield (SEY) of the chamber wall. We will report on recent SEY measurements performed at SLAC on TiN coatings and TiZrV non-evaporable getter thin films.

  8. Synthesis and characterization of SnO2 thin films prepared by dip-coating method

    NASA Astrophysics Data System (ADS)

    Carvalho, D. H. Q.; Schiavon, M. A.; Raposo, M. T.; de Paiva, R.; Alves, J. L. A.; Paniago, Roberto. M.; Speziali, N. L.; Ferlauto, A. S.; Ardisson, J. D.

    The optical, electrical and structural properties of SnOare responsible for a large number of technological 2 applications such as gas sensors, optical-electonic devices, varistors and displays. In this paper, we report the preparation of SnO thin films deposited on glass, quartz and silicon substrates by the technique of sol-gel dip-2coating. The films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ellipsometry and Mössbauer spectroscopy. We combine the experimental results with ab initio all-electrons calculations, using the density functional theory within the framework of the full-potential linear augmented plane waves method, in order to extract hyperfine parameters. The results show that the synthesis method is able to produce good quality films and that the theory can be helpful to determine quantities difficult to be measured experimentally.

  9. Studies on spin coated PANI/PMMA composite thin film: Effect of post-deposition heating

    NASA Astrophysics Data System (ADS)

    Yadav, J. B.; Patil, R. B.; Puri, R. K.; Puri, Vijaya

    2008-12-01

    Adhesion, structural and optical properties of spin coated PANI/PMMA composite thin films of different composition on glass substrate are reported. The effect of post-deposition heating for 100 °C, 125 °C and 150 °C is also reported. The adhesion of the film was found to increase from 712 ± 5 × 104 N/m 2 to 1602 ± 3 × 10 4 N/m 2 and refractive index decreased from 1.852 ± 0.005 to 1.650 ± 0.004 with increase in concentration of PMMA. Due to post-deposition heating adhesion, optical band gap increased but refractive index decreased.

  10. Wear and Durability Variation Compared with Thickness of Cutting Inserts Coated with AlTiN Thin Films

    NASA Astrophysics Data System (ADS)

    Bădănac, A.; Lupescu, O.; Manole, V.; Ungureanu, C.; Popa, M.

    2016-08-01

    During the use of cutting tools in the cutting process, they lose their exploitation indices after a certain range of working, due to the occurrence of wear phenomenon. Wear occurs due to the parameters variation of the working regimes, fact that involves in order to not overcoming the limits of the maximum allowable wear, application of methods, to increase their durability. In order to increase the cutting tools durability are known various methods of surface coating with materials with better properties than the material of the cutting tool. In the case of cutting inserts, are known many researches concerning their coating by vacuum deposition of thin layers of metal, methods as: physical vapour deposition and chemical vapour deposition. The coatings realized by vacuum deposition have gained special attention because of their unique physical and chemical properties for example excellent resistance to oxidation at high temperatures. The main characteristics which are checked in the deposition process of thin layers are: thickness and the wear resistance. In this study the authors carried out researches regarding the coatings of AlTiN in thin layers, on surface of some cutting inserts. It was measured the variation of the wear and durability compared with the thickness of AlTiN thin layers deposited on the cutting inserts.

  11. Thin films of spin-crossover coordination polymers with large thermal hysteresis loops prepared by nanoparticle spin coating.

    PubMed

    Tanaka, Daisuke; Aketa, Naoki; Tanaka, Hirofumi; Tamaki, Takashi; Inose, Tomoko; Akai, Tomoki; Toyama, Hirotaka; Sakata, Osami; Tajiri, Hiroo; Ogawa, Takuji

    2014-09-11

    This communication describes the synthesis of spin-crossover nanoparticles, which can disperse in various organic solvents without an excess amount of surfactants. The nanoparticles form homogeneous thin films on substrates by spin coating. The films show abrupt spin transitions with large thermal hysteresis loops.

  12. Tissue engineering of biphasic joint cartilage transplants.

    PubMed

    Kreklau, B; Sittinger, M; Mensing, M B; Voigt, C; Berger, G; Burmester, G R; Rahmanzadeh, R; Gross, U

    1999-09-01

    In isolated posttraumatic or idiopathic joint defects the chondral layers and adjacent subchondral spongy bone are usually destructed. For regeneration we suggest the in vitro formation of a cartilage-coated biomaterial carriers (biphases) in order to fill the correspondingjoint defects. In this study Biocoral, a natural coralline material made of calcium carbonate, and calcite, a synthetic calcium carbonate, were used as supports for the cultivation of bovine chondrocytes in a three-dimensional polymer fleece. The cell-polymer-structure was affixed to the biomaterial with a fibrin-cell-solution. The artificial cartilage formed a new matrix and fused with the underlying biomaterial. The results indicate a promising technical approach to anchor tissue engineered cartilage in joint defects.

  13. Ion beam sputter-deposited thin film coatings for protection of spacecraft polymers in low Earth orbit

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Mirtich, M. J.; Rutledge, S. K.; Swec, D. M.; Nahra, H. K.

    1985-01-01

    Ion beam sputter-deposited thin films of Al2O3, SiO2, and a codeposited mixture of predominantly SiO2 with small amounts of a fluoropolymer were evaluated both in laboratory plasma ashing tests and in space on board shuttle flight STS-8 for effectiveness in preventing oxidation of polyimide Kapton. Measurements of mass loss and optical performance of coated and uncoated polyimide samples exposed to the low Earth orbital environment are presented. Optical techniques were used to measure loss rates of protective films exposed to atomic oxygen. Results of the analysis of the space flight exposed samples indicate that thin film metal oxide coatings are very effective in protecting the polyimide. Metal oxide coatings with a small amount of fluoropolymer codeposited have the additional benefit of great flexibility.

  14. Ion beam sputter-deposited thin film coatings for protection of spacecraft polymers in low earth orbit

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Mirtich, M. J.; Rutledge, S. K.; Swec, D. M.; Nahra, H. K.

    1985-01-01

    Ion beam sputter-deposited thin films at Al2O3, SiO2, and a codeposited mixture of predominantly SiO2 with small amounts of fluoropolymer were evaluated both in laboratory plasma ashing tests and in space on board Shuttle flight STS-8 for effectiveness in preventing oxidation of polyimide Kapton. Measurements of mass loss and optical performance of coated and uncoated polyimide samples exposed to the low earth orbital environment are presented. Optical techniques were used to measure loss rates of protective films exposed to atomic oxygen. Results of the analysis of the space flight exposed samples indicate that thin film metal oxide coatings are very effective in protecting the polyimide. Metal oxide coatings with a small amount of fluoropolymer codeposited have the additional benefit of great flexibility.

  15. Electrostatic bonding of thin (approximately 3 mil) 7070 cover glass to Ta2O5 AR-coated thin (approximately 2 mil) silicon wafers and solar cells

    NASA Technical Reports Server (NTRS)

    Egelkrout, D. W.; Horne, W. E.

    1980-01-01

    Electrostatic bonding (ESB) of thin (3 mil) Corning 7070 cover glasses to Ta2O5 AR-coated thin (2 mil) silicon wafers and solar cells is investigated. An experimental program was conducted to establish the effects of variations in pressure, voltage, temperature, time, Ta2O5 thickness, and various prebond glass treatments. Flat wafers without contact grids were used to study the basic effects for bonding to semiconductor surfaces typical of solar cells. Solar cells with three different grid patterns were used to determine additional requirements caused by the raised metallic contacts.

  16. Direct-Coated Photoconducting Nanocrystalline PbS Thin Films with Tunable Band Gap

    NASA Astrophysics Data System (ADS)

    Vankhade, Dhaval; Kothari, Anjana; Chaudhuri, Tapas K.

    2016-06-01

    Nanocrystalline PbS thin films are deposited on glass by direct coating from a precursor solution of lead acetate and thiourea in methanol. A single coating has a thickness of 50 nm and greater thicknesses are obtained from layer by layer deposition. The films are smooth and shiny with roughness (rms) of about 1.5 nm. X-ray diffraction studies show that films are cubic PbS with crystallite size about 10 nm. The films are p-type with dark electrical conductivities in the range of 0.4-0.5 S/cm. These films are basically photoconducting. Photoconductivity monotonically increases with increase in thickness. The band gap of the films strongly depends on the thickness of the films. The band gap decreases from 2.4 eV to 1.6 eV as the thickness is increased from 50 nm to 450 nm. The tunability of the band gap is useful for technical applications, such as solar cells and photodetectors.

  17. The Characteristics of an Antibacterial TiAgN Thin Film Coated by Physical Vapor Deposition Technique.

    PubMed

    Kang, Byeong-Mo; Jeong, Woon-Jo; Park, Gye-Choon; Yoon, Dong-Joo; Ahn, Ho-Geun; Lim, Yeong-Seog

    2015-08-01

    In this work, we found the characteristics of an antibacterial TiAgN thin film coated on the pure titanium specimen via the physical vapor deposition process (PVD). TiAgN thin films were coated using TiAg alloy targets by arc ion plating method. Changing the process parameters, the surface analysis of TiAgN thin film was observed by FE-SEM and the force of adhesion was measured with Scratch Tester. The proliferation of human gingival fibroblast (HGF) cells was examined by XTT test assay and the antibacterial properties were investigated by culturing Streptococus Mutans (KCTC 3065) using paper disk techniques. At the result of experiment, cytotoxic effects were not found and the antibacterial effects against Streptococus Mutans were appeared over 5 wt% TiAgN specimens.

  18. Thin film deposition at atmospheric pressure using dielectric barrier discharges: Advances on three-dimensional porous substrates and functional coatings

    NASA Astrophysics Data System (ADS)

    Fanelli, Fiorenza; Bosso, Piera; Mastrangelo, Anna Maria; Fracassi, Francesco

    2016-07-01

    Surface processing of materials by atmospheric pressure dielectric barrier discharges (DBDs) has experienced significant growth in recent years. Considerable research efforts have been directed for instance to develop a large variety of processes which exploit different DBD electrode geometries for the direct and remote deposition of thin films from precursors in gas, vapor and aerosol form. This article briefly reviews our recent progress in thin film deposition by DBDs with particular focus on process optimization. The following examples are provided: (i) the plasma-enhanced chemical vapor deposition of thin films on an open-cell foam accomplished by igniting the DBD throughout the entire three-dimensional (3D) porous structure of the substrate, (ii) the preparation of hybrid organic/inorganic nanocomposite coatings using an aerosol-assisted process, (iii) the DBD jet deposition of coatings containing carboxylic acid groups and the improvement of their chemical and morphological stability upon immersion in water.

  19. Co-precipitation of tobramycin into biomimetically coated orthopedic fixation pins employing submicron-thin seed layers of hydroxyapatite.

    PubMed

    Sörensen, Jan H; Lilja, Mirjam; Åstrand, Maria; Sörensen, Torben C; Procter, Philip; Strømme, Maria; Steckel, Hartwig

    2014-01-01

    The migration, loosening and cut-out of implants and nosocomial infections are current problems associated with implant surgery. New innovative strategies to overcome these issues are emphasized in today's research. The current work presents a novel strategy involving co-precipitation of tobramycin with biomimetic hydroxyapatite (HA) formation to produce implant coatings that control local drug delivery to prevent early bacterial colonization of the implant. A submicron- thin HA layer served as seed layer for the co-precipitation process and allowed for incorporation of tobramycin in the coating from a stock solution of antibiotic concentrations as high as 20 mg/ml. Concentrations from 0.5 to 20 mg/ml tobramycin and process temperatures of 37 °C and 60 °C were tested to assess the optimal parameters for a thin tobramycin- delivering HA coating on discs and orthopedic fixation pins. The morphology and thickness of the coating and the drug-release profile were evaluated via scanning electron microscopy and high performance liquid chromatography. The coatings delivered pharmaceutically relevant amounts of tobramycin over a period of 12 days. To the best of our knowledge, this is the longest release period ever observed for a fast-loaded biomimetic implant coating. The presented approach could form the foundation for development of combination device/antibiotic delivery vehicles tailored to meet well-defined clinical needs while combating infections and ensuring fast implant in-growth.

  20. Structural and optical characterisation of tin dioxide thin films by sol-gel dip coating technique

    NASA Astrophysics Data System (ADS)

    Lekshmy, S. Sujatha; Berlin, I. John; Maneeshya, L. V.; Anitha; Joy, K.

    2015-02-01

    Tin oxide (SnO2) thin films were deposited on quartz substrates using sol-gel dip coating technique. X-ray diffraction (XRD) pattern indicated that the film annealed in air at 350°C was amorphous in nature, whereas, the films annealed in oxygen atmosphere at 350°C showed crystalline phase. The films were further annealed in oxygen atmosphere at 450°C and 550°C. All the diffraction peaks can be indexed to the tetragonal phase of SnO2 The surface morphology (SEM) showed that surface of all films were continuous and without micro cracks. The Energy dispersive X-ray spectroscopy (EDXS) spectra indicated an increase in the concentration of oxygen content with increase in annealing temperature. The energy band gap value for the film annealed in air was 3.88 eV. The optical band gap increased to 4.05 eV when annealed in O2 atmosphere. The photoluminescence (PL) spectra showed the presence of emission peaks in UV region and visible region of the electromagnetic spectra. Transparent oxide semiconductor SnO2 film finds potential application as an active channel layer for transparent thin film transistor.

  1. Photochromic glass thin film formed by the sol-gel coating method

    NASA Astrophysics Data System (ADS)

    Nakazumi, Hiroyuki; Nagashiro, Rie; Matsumoto, Shinya; Isagawa, Kakuzoh

    1994-10-01

    The photochromic gel thin films using 1'-butyl-3',3'-dimethyl-6-nitro-spiro[2H-1- benzopyran-2,2'-indoline] (1) and 1'-butyl-spiro[2H-indole-2,3'- [3H]naphtho[2,1-b][1,4]oxazine] (2) dispersed in sol in the sol-gel processing were prepared and photochromic behaviors of these films were investigated. A good transparent coating layer on glass surface was formed in the range of ca. 6 - 10 wt% of 1 or 2 to alkoxysilane, and was colored by UV irradiation. The absorption band formed by UV-irradiation disappeared by thermal decay and also by Vis irradiation for 1. The thermal fading of the colored form to the spiro form 1 or 2 is dependent on a matrix of the gels, the colored forms in the film starting from methyltriethoxysilane (MTES), which is expected to include larger pores than in the film starting from tetraethoxysilane (TEOS) or silane oligomer, show faster thermal fading which roughly follows the first order kinetics. The colored form in the gel is stabilized, compared with that in solution or bulk gel, and it is suggested that there are some kinds of colored species in thin gel films containing spiropyran 1, which may be some aggregates, whereas only a colored species from spironaphthooxazine 2 is suggested. Photochromic behavior of 2 in sol was also examined.

  2. Characterizations of multilayer ZnO thin films deposited by sol-gel spin coating technique

    NASA Astrophysics Data System (ADS)

    Khan, M. I.; Bhatti, K. A.; Qindeel, Rabia; Alonizan, Norah; Althobaiti, Hayat Saeed

    In this work, zinc oxide (ZnO) multilayer thin films are deposited on glass substrate using sol-gel spin coating technique and the effect of these multilayer films on optical, electrical and structural properties are investigated. It is observed that these multilayer films have great impact on the properties of ZnO. X-ray Diffraction (XRD) confirms that ZnO has hexagonal wurtzite structure. Scanning Electron Microscopy (SEM) showed the crack-free films which have uniformly distributed grains structures. Both micro and nano particles of ZnO are present on thin films. Four point probe measured the electrical properties showed the decreasing trend between the average resistivity and the number of layers. The optical absorption spectra measured using UV-Vis. showed the average transmittance in the visible region of all films is 80% which is good for solar spectra. The performance of the multilayer as transparent conducting material is better than the single layer of ZnO. This work provides a low cost, environment friendly and well abandoned material for solar cells applications.

  3. X-ray photoelectron spectroscopy study of the growth kinetics of biomimetically grown hydroxyapatite thin-film coatings

    NASA Astrophysics Data System (ADS)

    McLeod, K.; Kumar, S.; Dutta, N. K.; Smart, R. St. C.; Voelcker, N. H.; Anderson, G. I.

    2010-09-01

    Hydroxyapatite (HA) thin-film coatings grown biomimetically using simulated body fluid (SBF) are desirable for a range of applications such as improved fixation of fine- and complex-shaped orthopedic and dental implants, tissue engineering scaffolds and localized and sustained drug delivery. There is a dearth of knowledge on two key aspects of SBF-grown HA coatings: (i) the growth kinetics over short deposition periods, hours rather than weeks; and (ii) possible difference between the coatings deposited with and without periodic SBF replenishment. A study centred on these aspects is reported. X-ray photoelectron spectroscopy (XPS) has been used to study the growth kinetics of SBF-grown HA coatings for deposition periods ranging from 0.5 h to 21 days. The coatings were deposited with and without periodic replenishment of SBF. The XPS studies revealed that: (i) a continuous, stable HA coating fully covered the titanium substrate after a growth period of 13 h without SBF replenishment; (ii) thicker HA coatings about 1 μm in thickness resulted after a growth period of 21 days, both with and without SBF replenishment; and (iii) the Ca/P ratio at the surface of the HA coating was significantly lower than that in its bulk. No significant difference between HA grown with and without periodic replenishment of SBF was found. The coatings were determined to be carbonated, a characteristic desirable for improved implant fixation. The atomic force and scanning electron microscopies results suggested that heterogeneous nucleation and growth are the primary deposition mode for these coatings. Primary osteoblast cell studies demonstrated the biocompatibility of these coatings, i.e., osteoblast colony coverage of approximately 80%, similar to the control substrate (tissue culture polystyrene).

  4. Corrosion resistance of sintered NdFeB coated with SiC/Al bilayer thin films by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Huang, Yiqin; Li, Heqin; Zuo, Min; Tao, Lei; Wang, Wei; Zhang, Jing; Tang, Qiong; Bai, Peiwen

    2016-07-01

    The poor corrosion resistance of sintered NdFeB imposes a great challenge in industrial applications. In this work, the SiC/Al bilayer thin films with the thickness of 510 nm were deposited on sintered NdFeB by magnetron sputtering to improve the corrosion resistance. A 100 nm Al buffer film was used to reduce the internal stress between SiC and NdFeB and improve the surface roughness of the SiC thin film. The morphologies and structures of SiC/Al bilayer thin films and SiC monolayer film were investigated with FESEM, AFM and X-ray diffraction. The corrosion behaviors of sintered NdFeB coated with SiC monolayer film and SiC/Al bilayer thin films were analyzed by polarization curves. The magnetic properties were measured with an ultra-high coercivity permanent magnet pulse tester. The results show that the surface of SiC/Al bilayer thin films is more compact and uniform than that of SiC monolayer film. The corrosion current densities of SiC/Al bilayer films coated on NdFeB in acid, alkali and salt solutions are much lower than that of SiC monolayer film. The SiC/Al bilayer thin films have little influence to the magnetic properties of NdFeB.

  5. Advanced Fabrication Method for the Preparation of MOF Thin Films: Liquid-Phase Epitaxy Approach Meets Spin Coating Method.

    PubMed

    Chernikova, Valeriya; Shekhah, Osama; Eddaoudi, Mohamed

    2016-08-10

    Here, we report a new and advanced method for the fabrication of highly oriented/polycrystalline metal-organic framework (MOF) thin films. Building on the attractive features of the liquid-phase epitaxy (LPE) approach, a facile spin coating method was implemented to generate MOF thin films in a high-throughput fashion. Advantageously, this approach offers a great prospective to cost-effectively construct thin-films with a significantly shortened preparation time and a lessened chemicals and solvents consumption, as compared to the conventional LPE-process. Certainly, this new spin-coating approach has been implemented successfully to construct various MOF thin films, ranging in thickness from a few micrometers down to the nanometer scale, spanning 2-D and 3-D benchmark MOF materials including Cu2(bdc)2·xH2O, Zn2(bdc)2·xH2O, HKUST-1, and ZIF-8. This method was appraised and proved effective on a variety of substrates comprising functionalized gold, silicon, glass, porous stainless steel, and aluminum oxide. The facile, high-throughput and cost-effective nature of this approach, coupled with the successful thin film growth and substrate versatility, represents the next generation of methods for MOF thin film fabrication. Therefore, paving the way for these unique MOF materials to address a wide range of challenges in the areas of sensing devices and membrane technology.

  6. Very thin spin-coated silver films via transparent silver ink for surface plasmon resonance sensor applications.

    PubMed

    Son, Jung-Han; Lee, Dong Hun; Cho, Yong-Jin; Lee, Myung-Hyun

    2012-07-01

    We fabricated very thin silver films with thicknesses of 20 nm, 40 nm, and 60 nm on a prism using a spin coating method for surface plasmon resonance (SPR) image sensor module applications. An aqueous silver ionic complex solution was spin-coated and then thermally cured for 10 minutes at 150 degrees C in an oven. The spin-coated solid silver films possessed silver crystallinity. The prism modules with the 20-nm-, 40-nm- and 60-nm-thick thin silver films were applied to an SPR image sensor system. The coefficients of determination for the 20-nm-, 40-nm- and 60-nm-thick silver films were 0.923, 0.990 and 0.989, respectively when standard ethanol solutions with 0.1% intervals in the range of 20.0% to 20.5% were applied. The correlation is high-performed and the coefficients of determination are as close as 1. The spin coating method of very thin silver films for SPR image sensor modules is expected to be a very cost-effective solution because the films can be formed at a low temperature in a short period of time without requiring a vacuum system.

  7. Method and apparatus for enhanced evanescent fluorescence and color filtering using a high refractive index thin film coating

    DOEpatents

    Kao, Hung Pin; Schoeniger, Joseph; Yang, Nancy

    2001-01-01

    A technique for increasing the excitation and collection of evanescent fluorescence radiation emanating from a fiber optic sensor having a high refractive index (n.sub.r), dielectric thin film coating has been disclosed and described. The invention comprises a clad optical fiber core whose cladding is removed on a distal end, the distal end coated with a thin, non-porous, titanium dioxide sol-gel coating. It has been shown that such a fiber will exhibit increased fluorescence coupling due in part by 1) increasing the intensity of the evanescent field at the fiber core surface by a constructive interference effect on the propagating light, and 2) increasing the depth of penetration of the field in the sample. The interference effect created by the thin film imposes a wavelength dependence on the collection of the fluorescence and also suggests a novel application of thin films for color filtering as well as increasing collected fluorescence in fiber sensors. Collected fluorescence radiation increased by up to 6-fold over that of a bare fused silica fiber having a numerical aperture (N.A.) of O.6.

  8. Thickness-dependent photocatalytic performance of nanocrystalline TiO2 thin films prepared by sol-gel spin coating

    NASA Astrophysics Data System (ADS)

    Wu, Chung-Yi; Lee, Yuan-Ling; Lo, Yu-Shiu; Lin, Chen-Jui; Wu, Chien-Hou

    2013-09-01

    TiO2 nanocrystalline thin films on soda lime glass have been prepared by sol-gel spin coating. The thin films were characterized for surface morphology, crystal structure, chemical composition, thickness, and transparency by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ellipsometry, and UV-vis spectrophotometry. The films prepared by titanium tetraisopropoxide (TTIP) as the precursor under pH of 3.5 ± 0.5 and with calcination temperature of 450 ̊C for 3 h exhibited superior homogeneous aggregation, good optical transparency, superhydrophilicity, and reliable thickness. The effect of film thickness on the photocatalytic degradation of acid yellow 17 was investigated under UV irradiation. The photocatalytic activity was strongly correlated with the number of coatings and followed Langmuir-type kinetics. Under the same film thickness, TiO2 thin films prepared by 0.1 M TTIP exhibited more efficient photocatalytic activity than those prepared by 0.3 M TTIP. For thin films prepared by 0.1 M TTIP, the maximum specific photocatalytic activity occurred at 5 coatings with thickness of 93 ± 1 nm. A model was proposed to rationalize the dependence of the film thickness on the photocatalytic activity, which predicts the existence of an optimum film thickness.

  9. Biocompatibility versus peritoneal mesothelial cells of polypropylene prostheses for hernia repair, coated with a thin silica/silver layer.

    PubMed

    Muzio, Giuliana; Perero, Sergio; Miola, Marta; Oraldi, Manuela; Ferraris, Sara; Vernè, Enrica; Festa, Federico; Canuto, Rosa Angela; Festa, Valentino; Ferraris, Monica

    2016-04-29

    Hernias are generally repaired using synthetic prostheses. Infection may already be present or develop during implantation. Based on the increasing resistance to antibiotics, and the well-known antimicrobial properties of silver (Ag), the possibility of coating hernia prostheses with a nanostructured layer containing Ag was explored. Prostheses (Clear Mesh Composite [CMC]) made up of two polypropylene layers (macroporous light mesh and thin transparent film) were tested with human mesothelial cells from omentum biopsies. Mesotheliocytes modulate abdominal wall healing producing cytokines, growth factors, and adhesion molecules. Evaluating the growth of these cells on CMC or film alone showed that cell numbers on CMC increased over time, and were higher than those on film alone. Vimentin immunostaining confirmed the cells to be mesotheliocytes. Subsequently, the biocompatibility of mesh layer, coated or not with a thin layer of Ag/SiO2 -nanoclusters, was analyzed, showing no difference in absence or presence of Ag/SiO2 . Differently, TGF-β2 production, involved in tissue repair and fibrosis, increased in the presence of Ag/SiO2 . Moreover, Ag/SiO2 -coated mesh showed antibacterial properties. In conclusion, the mesh layer coated with Ag/SiO2 afforded cell growth, and showed antibacterial activity. Coating only the mesh layer did not decrease film transparency, and did not favor the formation of adhesions on the visceral side. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  10. Kinetically-controlled synthesis of ultra-small silica nanoparticles and ultra-thin coatings

    NASA Astrophysics Data System (ADS)

    Ding, Tao; Yao, Lin; Liu, Cuicui

    2016-02-01

    The understanding of silica as a polymer-like globule allows us to synthesize ultra-small silica nanoparticles (NPs) via a kinetic controlled process. The synthetic system is quite simple with Tetraethyl orthosilicate (TESO) as the precursor and H2O as the solvent and reactant. The reaction conditions are gentle with a temperature of around 35 to 60 °C with an incubation time of 7-12 hours. The final product of the silica NPs is very uniform and could be as small as 10 nm. The silica NPs can further grow up to 18 nm under the controlled addition of the precursors. Also, these silica NPs can be used as seeds to generate larger silica NPs with sizes ranging from 20 to 100 nm, which can be a useful supplement to the size range made by the traditional Stöber method. Moreover, these ultra-small Au NPs can be used as a depletion reagent or as building blocks for an ultrathin silica coating, which has significant applications in fine-tuning the plasmons of AuNPs and thin spacers for surface enhanced spectroscopies.The understanding of silica as a polymer-like globule allows us to synthesize ultra-small silica nanoparticles (NPs) via a kinetic controlled process. The synthetic system is quite simple with Tetraethyl orthosilicate (TESO) as the precursor and H2O as the solvent and reactant. The reaction conditions are gentle with a temperature of around 35 to 60 °C with an incubation time of 7-12 hours. The final product of the silica NPs is very uniform and could be as small as 10 nm. The silica NPs can further grow up to 18 nm under the controlled addition of the precursors. Also, these silica NPs can be used as seeds to generate larger silica NPs with sizes ranging from 20 to 100 nm, which can be a useful supplement to the size range made by the traditional Stöber method. Moreover, these ultra-small Au NPs can be used as a depletion reagent or as building blocks for an ultrathin silica coating, which has significant applications in fine-tuning the plasmons of Au

  11. Engineering Multifunctional Living Paints: Thin, Convectively-Assembled Biocomposite Coatings of Live Cells and Colloidal Latex Particles Deposited by Continuous Convective-Sedimentation Assembly

    NASA Astrophysics Data System (ADS)

    Jenkins, Jessica Shawn

    Advanced composite materials could be revolutionized by the development of methods to incorporate living cells into functional materials and devices. This could be accomplished by continuously and rapidly depositing thin ordered arrays of adhesive colloidal latex particles and live cells that maintain stability and preserve microbial reactivity. Convective assembly is one method of rapidly assembling colloidal particles into thin (<10 microm thick), ordered films with engineered compositions, thicknesses, and particle packing that offer several advantages over thicker randomly ordered composites, including enhanced cell stability and increased reactivity through minimized diffusion resistance to nutrients and reduced light scattering. This method can be used to precisely deposit live bacteria, cyanobacteria, yeast, and algae into biocomposite coatings, forming reactive biosensors, photoabsorbers, or advanced biocatalysts. This dissertation developed new continuous deposition and coating characterization methods for fabricating and characterizing <10 microm thick colloid coatings---monodispersed latex particle or cell suspensions, bimodal blends of latex particles or live cells and microspheres, and trimodal formulations of biomodal latex and live cells on substrates such as aluminum foil, glass, porous Kraft paper, polyester, and polypropylene. Continuous convective-sedimentation assembly (CSA) is introduced to enable fabrication of larger surface area and long coatings by constantly feeding coating suspension to the meniscus, thus expanding the utility of convective assembly to deposit monolayer or very thin films or multi-layer coatings composed of thin layers on a large scale. Results show thin, tunable coatings can be fabricated from diverse coating suspensions and critical coating parameters that control thickness and structure. Particle size ratio and charge influence deposition, convective mixing or demixing and relative particle locations. Substrate

  12. Silver activation on thin films of Ag-ZrCN coatings for antimicrobial activity.

    PubMed

    Ferreri, I; Calderon V, S; Escobar Galindo, R; Palacio, C; Henriques, M; Piedade, A P; Carvalho, S

    2015-10-01

    Nowadays, with the increase of elderly population and related health problems, knee and hip joint prosthesis are being widely used worldwide. However, failure of these invasive devices occurs in a high percentage thus demanding the revision of the chirurgical procedure. Within the reasons of failure, microbial infections, either hospital or subsequently-acquired, contribute in high number to the statistics. Staphylococcus epidermidis (S. epidermidis) has emerged as one of the major nosocomial pathogens associated with these infections. Silver has a historic performance in medicine due to its potent antimicrobial activity, with a broad-spectrum on the activity of different types of microorganisms. Consequently, the main goal of this work was to produce Ag-ZrCN coatings with antimicrobial activity, for the surface modification of hip prostheses. Thin films of ZrCN with several silver concentrations were deposited onto stainless steel 316 L, by DC reactive magnetron sputtering, using two targets, Zr and Zr with silver pellets (Zr+Ag target), in an atmosphere containing Ar, C2H2 and N2. The antimicrobial activity of the modified surfaces was tested against S. epidermidis and the influence of an activation step of silver was assessed by testing samples after immersion in a 5% (w/v) NaClO solution for 5 min. The activation procedure revealed to be essential for the antimicrobial activity, as observed by the presence of an inhibition halo on the surface with 11 at.% of Ag. The morphology analysis of the surface before and after the activation procedure revealed differences in silver distribution indicating segregation/diffusion of the metallic element to the film's surface. Thus, the results indicate that the silver activation step is responsible for an antimicrobial effect of the coatings, due to silver oxidation and silver ion release.

  13. Functionalized Antimicrobial Composite Thin Films Printing for Stainless Steel Implant Coatings.

    PubMed

    Floroian, Laura; Ristoscu, Carmen; Mihailescu, Natalia; Negut, Irina; Badea, Mihaela; Ursutiu, Doru; Chifiriuc, Mariana Carmen; Urzica, Iuliana; Dyia, Hussien Mohammed; Bleotu, Coralia; Mihailescu, Ion N

    2016-06-09

    In this work we try to address the large interest existing nowadays in the better understanding of the interaction between microbial biofilms and metallic implants. Our aimed was to identify a new preventive strategy to control drug release, biofilm formation and contamination of medical devices with microbes. The transfer and printing of novel bioactive glass-polymer-antibiotic composites by Matrix-Assisted Pulsed Laser Evaporation into uniform thin films onto 316 L stainless steel substrates of the type used in implants are reported. The targets were prepared by freezing in liquid nitrogen mixtures containing polymer and antibiotic reinforced with bioglass powder. The cryogenic targets were submitted to multipulse evaporation by irradiation with an UV KrF* (λ = 248 nm, τFWHM ≤ 25 ns) excimer laser source. The prepared structures were analyzed by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and profilometry, before and after immersion in physiological fluids. The bioactivity and the release of the antibiotic have been evaluated. We showed that the incorporated antibiotic underwent a gradually dissolution in physiological fluids thus supporting a high local treatment efficiency. Electrochemical measurements including linear sweep voltammetry and impedance spectroscopy studies were carried out to investigate the corrosion resistance of the coatings in physiological environments. The in vitro biocompatibility assay using the MG63 mammalian cell line revealed that the obtained nanostructured composite films are non-cytotoxic. The antimicrobial effect of the coatings was tested against Staphylococcus aureus and Escherichia coli strains, usually present in implant-associated infections. An anti-biofilm activity was evidenced, stronger against E. coli than the S. aureus strain. The results proved that the applied method allows for the fabrication of implantable biomaterials which shield metal ion release and possess

  14. A novel pillar indentation splitting test for measuring fracture toughness of thin ceramic coatings

    DOE PAGES

    Sebastiani, Marco; Johanns, K. E.; Herbert, Erik G.; ...

    2014-05-16

    Fracture toughness is an important material property that plays a role in determining the in-service mechanical performance and adhesion of thin ceramic films. Unfortunately, measuring thin film fracture toughness is affected by influences from the substrate and the large residual stresses that can exist in the films. In this paper, we explore a promising new technique that potentially overcomes these problems based on nanoindentation testing of micro-pillars produced by focused ion beam milling of the films. By making the pillar diameter approximately equal to its length, the residual stress in the pillar’s upper portion is almost fully relaxed, and whenmore » indented with a sharp Berkovich indenter, the pillars fracture by splitting at reproducible loads that are readily quantified by a sudden displacement excursion in the load displacement behavior. Cohesive finite element simulations are used to analyze and develop, for a given material, a simple relation between the critical load at failure, pillar radius, and fracture toughness. The main novel aspect of this work is that neither crack geometries nor crack sizes need to be measured post test. Furthermore, the residual stress can be measured at the same time with toughness, by comparing the indentation results from the stress-free pillars and the as-deposited film. The method is tested on three different hard coatings formed by physical vapor deposition: titanium nitride, chromium nitride, and a CrAlN/Si3N4 nanocomposite. Results compare well to independently measured values of fracture toughness for the three brittle films. The technique offers several benefits over existing methods.« less

  15. A novel pillar indentation splitting test for measuring fracture toughness of thin ceramic coatings

    SciTech Connect

    Sebastiani, Marco; Johanns, K. E.; Herbert, Erik G.; Carassiti, Fabio; Pharr, George Mathews

    2014-05-16

    Fracture toughness is an important material property that plays a role in determining the in-service mechanical performance and adhesion of thin ceramic films. Unfortunately, measuring thin film fracture toughness is affected by influences from the substrate and the large residual stresses that can exist in the films. In this paper, we explore a promising new technique that potentially overcomes these problems based on nanoindentation testing of micro-pillars produced by focused ion beam milling of the films. By making the pillar diameter approximately equal to its length, the residual stress in the pillar’s upper portion is almost fully relaxed, and when indented with a sharp Berkovich indenter, the pillars fracture by splitting at reproducible loads that are readily quantified by a sudden displacement excursion in the load displacement behavior. Cohesive finite element simulations are used to analyze and develop, for a given material, a simple relation between the critical load at failure, pillar radius, and fracture toughness. The main novel aspect of this work is that neither crack geometries nor crack sizes need to be measured post test. Furthermore, the residual stress can be measured at the same time with toughness, by comparing the indentation results from the stress-free pillars and the as-deposited film. The method is tested on three different hard coatings formed by physical vapor deposition: titanium nitride, chromium nitride, and a CrAlN/Si3N4 nanocomposite. Results compare well to independently measured values of fracture toughness for the three brittle films. The technique offers several benefits over existing methods.

  16. Mixed organotin(IV) chalcogenides: from molecules to Sn-S-Se semiconducting thin films deposited by spin-coating.

    PubMed

    Bouška, Marek; Střižík, Lukáš; Dostál, Libor; Růžička, Aleš; Lyčka, Antonín; Beneš, Ludvík; Vlček, Milan; Přikryl, Jan; Knotek, Petr; Wágner, Tomáš; Jambor, Roman

    2013-02-04

    Put the right spin on it: Mixed monomeric organotin(IV) chalcogenides of the general formula L(2)Sn(2)EX(2) containing two terminal Sn-X (X = Se, Te) bonds were prepared and were tested as potential single-source precursors for the deposition of semiconducting thin films. Spin-coating deposition of [{2,6-(Me(2)NCH(2))(2)C(6)H(3)}SnSe](2)(μ-S), as the useful single-source precursor, provided amorphous Sn-S-Se semiconducting thin films.

  17. Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

    SciTech Connect

    Nowak, G. Störmer, M.; Horstmann, C.; Kampmann, R.; Höche, D.; Lorenz, U.; Müller, M.; Schreyer, A.; Becker, H.-W.; Haese-Seiller, M.; Moulin, J.-F.; Pomm, M.; Randau, C.; Hall-Wilton, R.

    2015-01-21

    Due to the present shortage of {sup 3}He and the associated tremendous increase of its price, the supply of large neutron detection systems with {sup 3}He becomes unaffordable. Alternative neutron detection concepts, therefore, have been invented based on solid {sup 10}B converters. These concepts require development in thin film deposition technique regarding high adhesion, thickness uniformity and chemical purity of the converter coating on large area substrates. We report on the sputter deposition of highly uniform large-area {sup 10}B{sub 4}C coatings of up to 2 μm thickness with a thickness deviation below 4% using the Helmholtz-Zentrum Geesthacht large area sputtering system. The {sup 10}B{sub 4}C coatings are x-ray amorphous and highly adhesive to the substrate. Material analysis by means of X-ray-Photoelectron Spectroscopy, Secondary-Ion-Mass-Spectrometry, and Rutherford-Back-Scattering (RBS) revealed low impurities concentration in the coatings. The isotope composition determined by Secondary-Ion-Mass-Spectrometry, RBS, and inelastic nuclear reaction analysis of the converter coatings evidences almost identical {sup 10}B isotope contents in the sputter target and in the deposited coating. Neutron conversion and detection test measurements with variable irradiation geometry of the converter coating demonstrate an average relative quantum efficiency ranging from 65% to 90% for cold neutrons as compared to a black {sup 3}He-monitor. Thus, these converter coatings contribute to the development of {sup 3}He-free prototype detectors based on neutron grazing incidence. Transferring the developed coating process to an industrial scale sputtering system can make alternative {sup 3}He-free converter elements available for large area neutron detection systems.

  18. Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

    NASA Astrophysics Data System (ADS)

    Nowak, G.; Störmer, M.; Becker, H.-W.; Horstmann, C.; Kampmann, R.; Höche, D.; Haese-Seiller, M.; Moulin, J.-F.; Pomm, M.; Randau, C.; Lorenz, U.; Hall-Wilton, R.; Müller, M.; Schreyer, A.

    2015-01-01

    Due to the present shortage of 3He and the associated tremendous increase of its price, the supply of large neutron detection systems with 3He becomes unaffordable. Alternative neutron detection concepts, therefore, have been invented based on solid 10B converters. These concepts require development in thin film deposition technique regarding high adhesion, thickness uniformity and chemical purity of the converter coating on large area substrates. We report on the sputter deposition of highly uniform large-area 10B4C coatings of up to 2 μm thickness with a thickness deviation below 4% using the Helmholtz-Zentrum Geesthacht large area sputtering system. The 10B4C coatings are x-ray amorphous and highly adhesive to the substrate. Material analysis by means of X-ray-Photoelectron Spectroscopy, Secondary-Ion-Mass-Spectrometry, and Rutherford-Back-Scattering (RBS) revealed low impurities concentration in the coatings. The isotope composition determined by Secondary-Ion-Mass-Spectrometry, RBS, and inelastic nuclear reaction analysis of the converter coatings evidences almost identical 10B isotope contents in the sputter target and in the deposited coating. Neutron conversion and detection test measurements with variable irradiation geometry of the converter coating demonstrate an average relative quantum efficiency ranging from 65% to 90% for cold neutrons as compared to a black 3He-monitor. Thus, these converter coatings contribute to the development of 3He-free prototype detectors based on neutron grazing incidence. Transferring the developed coating process to an industrial scale sputtering system can make alternative 3He-free converter elements available for large area neutron detection systems.

  19. Kinetic Effects on Self-Assembly and Function of Protein-Polymer Bioconjugates in Thin Films Prepared by Flow Coating.

    PubMed

    Chang, Dongsook; Huang, Aaron; Olsen, Bradley D

    2017-01-01

    The self-assembly of nanostructured globular protein arrays in thin films is demonstrated using protein-polymer block copolymers based on a model protein mCherry and the polymer poly(oligoethylene glycol acrylate) (POEGA). Conjugates are flow coated into thin films on a poly(ethylene oxide) grafted Si surface, forming self-assembled cylindrical nanostructures with POEGA domains selectively segregating to the air-film interface. Long-range order and preferential arrangement of parallel cylinders templated by selective surfaces are demonstrated by controlling relative humidity. Long-range order increases with coating speed when the film thicknesses are kept constant, due to reduced nucleation per unit area of drying film. Fluorescence emission spectra of mCherry in films prepared at <25% relative humidity shows a small shift suggesting that proteins are more perturbed at low humidity than high humidity or the solution state.

  20. Kinetic Effects on Self-Assembly and Function of Protein-Polymer Bioconjugates in Thin Films Prepared by Flow Coating

    SciTech Connect

    Chang, Dongsook; Huang, Aaron; Olsen, Bradley D.

    2016-11-04

    The self-assembly of nanostructured globular protein arrays in thin films is demonstrated using protein–polymer block copolymers based on a model protein mCherry and the polymer poly(oligoethylene glycol acrylate) (POEGA). Conjugates are flow coated into thin films on a poly(ethylene oxide) grafted Si surface, forming self-assembled cylindrical nanostructures with POEGA domains selectively segregating to the air–film interface. Long-range order and preferential arrangement of parallel cylinders templated by selective surfaces are demonstrated by controlling relative humidity. Long-range order increases with coating speed when the film thicknesses are kept constant, due to reduced nucleation per unit area of drying film. Fluorescence emission spectra of mCherry in films prepared at <25% relative humidity shows a small shift suggesting that proteins are more perturbed at low humidity than high humidity or the solution state.

  1. Polyurea spin-coated thin films: Pyro- and piezoelectric properties and application to infrared sensors

    NASA Astrophysics Data System (ADS)

    Morimoto, Masahiro; Koshiba, Yasuko; Misaki, Masahiro; Ishida, Kenji

    2015-04-01

    We have investigated the pyro- and piezoelectric properties of polyurea spin-coated films with thermal and chemical stability and their performance as infrared sensors. The piezoelectric coefficient d33 was measured by a laser Doppler vibrometer to be 23.5 pC/N. This coefficient increased with the poling electric field up to around 75 MV/m, suggesting that the polyurea dipole is aligned by applying an electric field greater than 75 MV/m. When a triangular thermal wave was applied, a square-wave pyroelectric current was observed and the pyroelectric coefficient measured to be 5.11 µC/(m2·K). The infrared sensor performance of the polyurea thin film was examined by measuring the voltage sensitivity to infrared irradiation. The obtained result of 70.4 V/W at 1 Hz is consistent with the results calculated from the measured pyroelectric coefficient. Our findings suggest that the performance of the sensor may be improved by increasing the pyroelectric coefficient of the polyurea films.

  2. Thin polyphenylene vinylene electrophoretically and spin-coated films - photoelectrical properties

    NASA Astrophysics Data System (ADS)

    Mladenova, D.; Zhivkov, I.; Ouzzane, I.; Vala, M.; Heinrichova, P.; Budurova, D.; Weiter, M.

    2012-12-01

    Electrophoretic deposition (EPD) and spin coating (SC) techniques were compared on poly[2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) used as a model material. Absorption spectra measured in a toluene solution and a toluene/ acetonitrile suspension with the same MDMO-PPV concentration of 0.0033 g.l-1 were analysed. An observed broadening of the characteristic absorption peak could be related to the formation of tightly-folded polymer chains in the suspension. Thin films of about 300 nm thickness were prepared by EPD from suspension and SC from solution with a concentration of 0.0033 g.l-1 and 8.95 g.l-1, respectively. The ITO|MDMO-PPV|Al structures with EPD MDMO-PPV films behave as a photovoltaic cell, while the same sample configuration with SC MDMO-PPV films acts more like a photoresistor. EPD and SC films exhibit the same charge-carrier photogeneration mechanism. It was clearly demonstrated that the EPD method uses the deposited material more efficiently, producing films with better photoelectrical properties.

  3. Dip coated nanocrystalline CdZnS thin films for solar cell application

    SciTech Connect

    Dongre, J. K. Chaturvedi, Mahim; Patil, Yuvraj; Sharma, Sandhya; Jain, U. K.

    2015-07-31

    Nanocrystalline cadmium sulfide (CdS) and zinc cadmium sulfide (ZnCdS) thin films have been grown via simple and low cost dip coating technique. The prepared films are characterized by X-ray diffraction (XRD), atomic force microscopic (AFM) and UV-VIS spectrophotometer techniques to reveal their structural, morphological and optical properties. XRD shows that both samples grown have zinc blende structure. The grain size is calculated as 6.2 and 8 nm using Scherrer’s formula. The band gap value of CdS and CdZnS film is estimated to be 2.58 and 2.69 eV respectively by UV-vis spectroscopy. Photoelectrochemical (PEC) investigations are carried out using cell configuration as n-CdZnS/(1M NaOH + 1M Na2S + 1M S)/C. The photovoltaic output characteristic is used to calculate fill-factor (FF) and solar conversion efficiency (η)

  4. Distinct surface hydration behaviors of boron-rich boride thin film coatings

    NASA Astrophysics Data System (ADS)

    Lu, Xinhong; Liu, Wei; Ouyang, Jun; Tian, Yun

    2014-08-01

    In this work, the surface boron chemical states and surface hydration behaviors of the as-deposited and annealed boron-rich boride thin film coatings, including AlMgB14, TiB2 and AlMgB14-TiB2, were systematically studied by use of X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The XPS results indicate that boron at annealed AlMgB14 film surface can be oxidized; surprisingly, such oxidation does not lead to the formation of boric acid in ambient air. Instead, boric acid can be produced at the surface of annealed TiB2 film and AlMgB14-TiB2 film. It is shown, via the water contact angle measurements, that these boride films exhibit distinct surface wettability characteristics, which are believed to result in the observed surface hydration processes. Furthermore, we found anatase TiO2 formation plays a major role in the surface wetting behaviors for these boride films.

  5. Cocktails of paste coatings for performance enhancement of CuInGaS(2) thin-film solar cells.

    PubMed

    An, Hee Sang; Cho, Yunae; Park, Se Jin; Jeon, Hyo Sang; Hwang, Yun Jeong; Kim, Dong-Wook; Min, Byoung Koun

    2014-01-22

    To fabricate low-cost and printable wide-bandgap CuInxGa1-xS2 (CIGS) thin-film solar cells, a method based on a precursor solution was developed. In particular, under this method, multiple coatings with two pastes with different properties (e.g., viscosity) because of the different binder materials added were applied. Paste A could form a thin, dense layer enabling a high-efficiency solar cell but required several coating and drying cycles for the desired film thickness. On the other hand, paste B could easily form one-micrometer-thick films by means of a one-time spin-coating process but the porous microstructure limited the solar cell performance. Three different configurations of the CIGS films (A + B, B + A, and A + B + A) were realized by multiple coatings with the two pastes to find the optimal stacking configuration for a combination of the advantages of each paste. Solar cell devices using these films showed a notable difference in their photovoltaic characteristics. The bottom dense layer increased the minority carrier diffusion length and enhanced the short-circuit current. The top dense layer could suppress interface recombination but exhibited a low optical absorption, thereby decreasing the photocurrent. As a result, the A + B configuration could be suggested as a desirable simple stacking structure. The solar cell with A + B coating showed a highly improved efficiency (4.66%) compared to the cell with a film prepared by paste B only (2.90%), achieved by simple insertion of a single thin (200 nm), dense layer between the Mo back contact and a thick porous CIGS layer.

  6. Structural, morphological, optical and electrical properties of Cu0.87Se thin films coated by electron beam evaporation method

    NASA Astrophysics Data System (ADS)

    Bhuvaneswari, P. V.; Ramamurthi, K.; Ramesh Babu, R.; Moorthy Babu, S.

    2015-09-01

    Copper selenide powder was synthesized adopting a two-step chemical route. X-ray diffraction analysis showed that the synthesized material consists of mixed phases of Cu3Se2, Cu7Se4 and Cu0.87Se. Synthesized material was used to deposit thin films at the substrate temperature of 200, 300, 400 and 500 °C by electron beam evaporation method. The substrate temperature of 200 °C yielded amorphous film, whereas the substrate temperature of 300, 400 and 500 °C produced Cu0.87Se single-phase thin film. Atomic force microscopic studies showed that the film coated at 400 °C possesses relatively lower average roughness. The direct band gap of Cu0.87Se varies from 1.67 to 1.81 eV. Thin film coated at 400 °C shows the minimum resistivity of 5.2 × 10-4 Ω cm, whereas the film coated at 300 °C possesses the maximum mobility of 8.2 cm2/Vs.

  7. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  8. Synthesis and characterization of transparent conductive zinc oxide thin films by sol-gel spin coating method

    NASA Astrophysics Data System (ADS)

    Winarski, David

    Zinc oxide has been given much attention recently as it is promising for various semiconductor device applications. ZnO has a direct band gap of 3.3 eV, high exciton binding energy of 60 meV and can exist in various bulk powder and thin film forms for different applications. ZnO is naturally n-type with various structural defects, which sparks further investigation into the material properties. Although there are many potential applications for this ZnO, an overall lack of understand and control of intrinsic defects has proven difficult to obtain consistent, repeatable results. This work studies both synthesis and characterization of zinc oxide in an effort to produce high quality transparent conductive oxides. The sol-gel spin coating method was used to obtain highly transparent ZnO thin films with high UV absorbance. This research develops a new more consistent method for synthesis of these thin films, providing insight for maintaining quality control for each step in the procedure. A sol-gel spin coating technique is optimized, yielding highly transparent polycrystalline ZnO thin films with tunable electrical properties. Annealing treatment in hydrogen and zinc atmospheres is researched in an effort to increase electrical conductivity and better understand intrinsic properties of the material. These treatment have shown significant effects on the properties of ZnO. Characterization of doped and undoped ZnO synthesized by the sol-gel spin coating method was carried out using scanning electron microscopy, UV-Visible range absorbance, X-ray diffraction, and the Hall Effect. Treatment in hydrogen shows an overall decrease in the number of crystal phases and visible absorbance while zinc seems to have the opposite effect. The Hall Effect has shown that both annealing environments increase the n-type conductivity, yielding a ZnO thin film with a carrier concentration as high as 3.001 x 1021 cm-3.

  9. Examination of the influence of coatings on thin superalloy sections. Volume 2: Detailed procedures and data. [corrosion resistance

    NASA Technical Reports Server (NTRS)

    Kaufman, M.

    1974-01-01

    The effects of an aluminide coating, Codep B-1, and of section thickness were investigated on two cast nickel base superalloys, Rene 80 and Rene 120. Cast section thicknesses ranged from 0.038 cm to 0.15 cm. Simulated engine exposures for 1000 hours at 899C or 982C in a jet fuel burner rig with cyclic air cooling were studied, as were the effects of surface machining before coating and re-machining and re-coating after exposures. The properties evaluated included tensile at room temperature., 871C and 982C, stress rupture at 760C, 871C, 982C and 1093C, high cycle mechanical fatigue at room temperature., and thermal fatigue with a 1093C peak temperature. Thin sections had tensile strengths similar to standard size bars up to 871C and lower strengths at 982C and above, with equivalent elongation, and stress rupture life was lower for thin sections at all test conditions. The aluminide coating lowered tensile and rupture strengths up to 871C, with greater effects on thinner specimens. Elevated temperature exposure lowered tensile and rupture strengths of thinner specimens at the lower test temperatures. Surface machining had little effect on properties, but re-machining after exposure reduced thickness and increased metallurgical changes enough to lower properties at most test conditions.

  10. Ultra-thin atomic-layer deposited alumina incorporating silica sol makes ultra-durable antireflection coatings

    NASA Astrophysics Data System (ADS)

    Li, Jia; Lan, Pinjun; Xu, Hua; Zhang, Xianpeng; Yang, Ye; Tan, Ruiqin; Jylhä, Olli; Lu, Yuehui

    2012-11-01

    We propose a strategy to make soda-lime glass maintain both high transparency and long-term durability in stringent high temperature and humid environments. Experiments reveal that the double-layered coatings with 110-nm-thick SiO2 and ultra-thin 25-nm- or 50-nm-thick Al2O3 layers, prepared by sol-gel dip coating and atomic layer deposition (ALD), respectively, exhibit the improvement of 5.88-6.32% in Tave (the average transmittance from the wavelength of 400-700 nm), as compared with that of the bare glass. On the other hand, the highly accelerated temperature and humidity stress test (HAST) confirms that both samples can sustain the 180 h test without any proven transmittance degradation, while the normalized Tave of the bare glass drastically drops to 43.1% of the initial value after the 108 h HAST. It implies that the ultra-thin Al2O3 films prepared by ALD, followed by dip-coated low-index layers such as SiO2 or nanostructured layer, can achieve both higher average transmittance and better durability, which would be of significance for the applications of ALD and dip coating techniques in the fields of consumer electronics, architecture with glass facades, and photovoltaics.

  11. Structural characterization and comparison of iridium, platinum and gold/palladium ultra-thin film coatings for STM of biomolecules

    SciTech Connect

    Sebring, R.; Arendt, P.; Imai, B.; Bradbury, E.M.; Gatewood, J.; Panitz, J.; Yau, P.

    1997-10-30

    Scanning tunneling microscopy (STM) is capable of atomic resolution and is ideally suited for imaging surfaces with uniform work function. A biological sample on a conducting substrate in air does not meet this criteria and requires a conductive coating for stable and reproducible STM imaging. In this paper, the authors describe the STM and transmission electron microscopy (TEM) characterization of ultra-thin ion-beam sputtered films of iridium and cathode sputtered gold/palladium and platinum films on highly ordered pyrolytic graphite (HOPG) which were developed for use as biomolecule coatings. The goals were the development of metal coatings sufficiently thin and fine grained that 15--20 {angstrom} features of biological molecules could be resolved using STM, and the development of a substrate/coating system which would allow complementary TEM information to be obtained for films and biological molecules. The authors demonstrate in this paper that ion-beam sputtered iridium on highly ordered pyrolytic graphite (HOPG) has met both these goals. The ion-beam sputtered iridium produced a very fine grained (< 10 {angstrom}) continuous film at 5--6 {angstrom} thickness suitable for stable air STM imaging. In comparison, cathode sputtered platinum produced 16 {angstrom} grains with the thinnest continuous film at 15 {angstrom} thickness, and the sputtered gold/palladium produced 25 {angstrom} grains with the thinnest continuous film at 18 {angstrom} thickness.

  12. Tribo-mechanical properties of thin boron coatings deposited on polished cobalt alloy surfaces for orthopedic applications

    PubMed Central

    Klepper, C. C.; Williams, J. M.; Truhan, J.J.; Qu, J.; Riester, L.; Hazelton, R. C.; Moschella, J.J.; Blau, P.J.; Anderson, J.P.; Popoola, O.O.; Keitz, M.D.

    2008-01-01

    This paper presents experimental evidence that thin (<∼200 nm) boron coatings, deposited with a (vacuum) cathodic arc technique on pre-polished Co-Cr-Mo surfaces, could potentially extend the life of metal-on-polymer orthopedic devices using cast Co-Cr-Mo alloy for the metal component. The primary tribological test used a linear, reciprocating pin-on-disc arrangement, with pins made of ultra-high molecular weight polyethylene. The disks were cast Co-Cr-Mo samples that were metallographically polished and then coated with boron at a substrate bias of 500 V and at about 100 °C. The wear tests were carried out in a saline solution to simulate the biological environment. The improvements were manifested by the absence of a detectable wear track scar on the coated metal component, while significant polymer transfer film was detected on the uncoated (control) samples tested under the same conditions. The polymer transfer track was characterized with both profilometry and Rutherford Backscattering Spectroscopy. Mechanical characterization of the thin films included nano-indentation, as well as additional pin-on-disk tests with a steel ball to demonstrate adhesion, using ultra-high frequency acoustic microscopy to probe for any void occurrence at the coating-substrate interface. PMID:19340285

  13. The long-period fiber grating coated with Langmuir-Blodgett thin film for applications on biochemistry sensors

    NASA Astrophysics Data System (ADS)

    Wang, Liwei; Zhang, Min; Liao, Yanbiao; Zhu, Jing

    2005-11-01

    The resonant wavelength of long-period fiber gratings (LPFGs) is very sensitive to the ambient refractive index. LPFGs will have many potential applications on biochemistry sensors and environment monitor system. At present, LPFGs chemical sensors can only measure the medium, which has lower refractive index than that of the fiber cladding, however, the detecting range can be greatly enlarged if the LPFGs coated with Langmuir-Blodgett thin film are used. LPFGs will have more extensive applications with the mature of the L-B thin film technology. In this paper, the spectrum performance of the resonant wavelength of LPFGs varying with the changes of the ambient refractive index (1< n < 1.8) is theoretically analyzed. As the ambient index is increased, each resonance wavelength first shifts toward the shorter-wavelength direction and then disappears where the value of n is about 1.45. When the ambient index is larger than that of the cladding (~1.45), the resonance wavelengths reappear at slightly longer wavelength than those measured in ambient air. According to the mode coupling method, the theoretical four-layered fiber model is developed on the relationships among the resonant wavelengths of LPFGs coated with L-B thin film, the refractive index and thickness of the L-B thin film, and ambient refractive index. The shift of the resonant wavelength is calculated through numeric method and is presented graphically.

  14. Long-Wavelength Infrared Sensing by Cytochrome C Protein Thin Film Deposited by the Spin Coating Method

    PubMed Central

    Lai, Bo-Yu; Chu, Chung-Hao; Su, Guo-Dung John

    2013-01-01

    High infrared absorption, large temperature coefficient of resistance (TCR) and small 1/f noise are preferred characteristics for sensing materials used in bolometers. In this paper, we discuss a cytochrome c protein as a potential sensing material for long-wavelength bolometers. We simulated and experimentally proved high infrared absorption of cytochrome c in the wavelength between 8 μm and 14 μm. Cytochrome c thin films were deposited on a hydrophilic surface using the spin coating method. The resistance variation with temperature is measured and we show that the TCR of cytochrome c thin films is consistently higher than 20%. The measured values of 1/f noise were as low as 2.33 × 10−13 V2/Hz at 60 Hz. Finally, we test the reliability of cytochrome c by measuring the resistance changes over time under varying conditions. We found that cytochrome c thin films deteriorated significantly without appropriate packaging. PMID:24264331

  15. Long-wavelength infrared sensing by cytochrome C protein thin film deposited by the spin coating method.

    PubMed

    Lai, Bo-Yu; Chu, Chung-Hao; Su, Guo-Dung John

    2013-11-20

    High infrared absorption, large temperature coefficient of resistance (TCR) and small 1/f noise are preferred characteristics for sensing materials used in bolometers. In this paper, we discuss a cytochrome c protein as a potential sensing material for long-wavelength bolometers. We simulated and experimentally proved high infrared absorption of cytochrome c in the wavelength between 8 μm and 14 μm. Cytochrome c thin films were deposited on a hydrophilic surface using the spin coating method. The resistance variation with temperature is measured and we show that the TCR of cytochrome c thin films is consistently higher than 20%. The measured values of 1/f noise were as low as 2.33 × 10⁻¹³ V²/Hz at 60 Hz. Finally, we test the reliability of cytochrome c by measuring the resistance changes over time under varying conditions. We found that cytochrome c thin films deteriorated significantly without appropriate packaging.

  16. Responsive polymer/gold nanoparticle composite thin films fabricated by solvent-induced self-assembly and spin-coating.

    PubMed

    Li, Dongxiang; Lee, Ji Yong; Kim, Dong Ha

    2011-02-15

    Self-assembled poly(4-vinylpyridine)-grafted gold (Au) nanoparticles (NPs) and polystyrene-b-poly(4-vinylpyridine) block copolymers were fabricated by the introduction of a selective solvent to a common solution. The assembled mixtures were spin-coated onto solid substrates to fabricate composite gold/polymer thin films composed of copolymer-hybridized Au NPs and independent copolymer micelles. The obtained composite Au thin films had variable localized surface plasmon resonance (LSPR) bands and microscopic morphologies upon vapor annealing with selective solvents because the adsorption and dissolving of solvent molecules into the films could rearrange the copolymer block. The hybrid nanostructured Au thin films may have potential in vapor sensing and organic assays.

  17. Linking Precursor Alterations to Nanoscale Structure and Optical Transparency in Polymer Assisted Fast-Rate Dip-Coating of Vanadium Oxide Thin Films

    NASA Astrophysics Data System (ADS)

    Glynn, Colm; Creedon, Donal; Geaney, Hugh; Armstrong, Eileen; Collins, Timothy; Morris, Michael A.; Dwyer, Colm O.'

    2015-06-01

    Solution processed metal oxide thin films are important for modern optoelectronic devices ranging from thin film transistors to photovoltaics and for functional optical coatings. Solution processed techniques such as dip-coating, allow thin films to be rapidly deposited over a large range of surfaces including curved, flexible or plastic substrates without extensive processing of comparative vapour or physical deposition methods. To increase the effectiveness and versatility of dip-coated thin films, alterations to commonly used precursors can be made that facilitate controlled thin film deposition. The effects of polymer assisted deposition and changes in solvent-alkoxide dilution on the morphology, structure, optoelectronic properties and crystallinity of vanadium pentoxide thin films was studied using a dip-coating method using a substrate withdrawal speed within the fast-rate draining regime. The formation of sub-100 nm thin films could be achieved rapidly from dilute alkoxide based precursor solutions with high optical transmission in the visible, linked to the phase and film structure. The effects of the polymer addition was shown to change the crystallized vanadium pentoxide thin films from a granular surface structure to a polycrystalline structure composed of a high density of smaller in-plane grains, resulting in a uniform surface morphology with lower thickness and roughness.

  18. Linking Precursor Alterations to Nanoscale Structure and Optical Transparency in Polymer Assisted Fast-Rate Dip-Coating of Vanadium Oxide Thin Films.

    PubMed

    Glynn, Colm; Creedon, Donal; Geaney, Hugh; Armstrong, Eileen; Collins, Timothy; Morris, Michael A; O'Dwyer, Colm

    2015-06-30

    Solution processed metal oxide thin films are important for modern optoelectronic devices ranging from thin film transistors to photovoltaics and for functional optical coatings. Solution processed techniques such as dip-coating, allow thin films to be rapidly deposited over a large range of surfaces including curved, flexible or plastic substrates without extensive processing of comparative vapour or physical deposition methods. To increase the effectiveness and versatility of dip-coated thin films, alterations to commonly used precursors can be made that facilitate controlled thin film deposition. The effects of polymer assisted deposition and changes in solvent-alkoxide dilution on the morphology, structure, optoelectronic properties and crystallinity of vanadium pentoxide thin films was studied using a dip-coating method using a substrate withdrawal speed within the fast-rate draining regime. The formation of sub-100 nm thin films could be achieved rapidly from dilute alkoxide based precursor solutions with high optical transmission in the visible, linked to the phase and film structure. The effects of the polymer addition was shown to change the crystallized vanadium pentoxide thin films from a granular surface structure to a polycrystalline structure composed of a high density of smaller in-plane grains, resulting in a uniform surface morphology with lower thickness and roughness.

  19. Linking Precursor Alterations to Nanoscale Structure and Optical Transparency in Polymer Assisted Fast-Rate Dip-Coating of Vanadium Oxide Thin Films

    PubMed Central

    Glynn, Colm; Creedon, Donal; Geaney, Hugh; Armstrong, Eileen; Collins, Timothy; Morris, Michael A.; Dwyer, Colm O’

    2015-01-01

    Solution processed metal oxide thin films are important for modern optoelectronic devices ranging from thin film transistors to photovoltaics and for functional optical coatings. Solution processed techniques such as dip-coating, allow thin films to be rapidly deposited over a large range of surfaces including curved, flexible or plastic substrates without extensive processing of comparative vapour or physical deposition methods. To increase the effectiveness and versatility of dip-coated thin films, alterations to commonly used precursors can be made that facilitate controlled thin film deposition. The effects of polymer assisted deposition and changes in solvent-alkoxide dilution on the morphology, structure, optoelectronic properties and crystallinity of vanadium pentoxide thin films was studied using a dip-coating method using a substrate withdrawal speed within the fast-rate draining regime. The formation of sub-100 nm thin films could be achieved rapidly from dilute alkoxide based precursor solutions with high optical transmission in the visible, linked to the phase and film structure. The effects of the polymer addition was shown to change the crystallized vanadium pentoxide thin films from a granular surface structure to a polycrystalline structure composed of a high density of smaller in-plane grains, resulting in a uniform surface morphology with lower thickness and roughness. PMID:26123117

  20. Temperature dependence of microwave absorption phenomena in single and biphase soft magnetic microwires

    NASA Astrophysics Data System (ADS)

    El Kammouni, Rhimou; Vázquez, Manuel; Lezama, Luis; Kurlyandskaya, Galina; Kraus, Ludek

    2014-11-01

    The microwave absorption phenomena of single and biphase magnetic microwires with soft magnetic behavior have been investigated as a function of DC applied magnetic field using two alternative techniques: (i) absorption measurements in the temperature range of 4-300 K using a spectrometer operating at X-band frequency, at 9.5 GHz, and (ii) room-temperature, RT, ferromagnetic resonance measurements in a network analyzer in the frequency range up to 20 GHz. Complementary low-frequency magnetic characterization was performed in a Vibrating Sample Magnetometer. Studies have been performed for 8 μm diameter small-magnetostriction amorphous CoFeSiB single-phase microwire, coated by micrometric Pyrex layer, and after electroplating an external shell, 2 μm or 4 μm thick, of FeNi alloys. For single phase CoFeSiB microwire, a single absorption is observed, whose DC field dependence of resonance frequency at RT fits to a Kittel-law behavior for in-plane magnetized thin film. The temperature dependence behavior shows a monotonic increase in the resonance field, Hr, with temperature. A parallel reduction of the circular anisotropy field, HK, is deduced from the temperature dependence of hysteresis loops. For biphase, CoFeSiB/FeNi, microwires, the absorption phenomena at RT also follow the Kittel condition. The observed opposite evolution with temperature of resonance field, Hr, in 2 and 4 μm thick FeNi samples is interpreted considering the opposite sign of magnetostriction of the respective FeNi layers. The stress-induced magnetic anisotropy field, HK, in the FeNi shell is deduced to change sign at around 130 K.

  1. Morphology, conductivity, and wetting characteristics of PEDOT:PSS thin films deposited by spin and spray coating

    NASA Astrophysics Data System (ADS)

    Zabihi, F.; Xie, Y.; Gao, S.; Eslamian, M.

    2015-05-01

    The goal of this paper is to study the characteristics of PEDOT:PSS thin films and the effects of varying the processing parameters on the structure, functionality, and surface wetting of spun-on and spray-on PEDOT:PSS thin films. PEDOT:PSS is a polymer mixture, which is electrically conductive and transparent and, therefore, is an attractive material for some optoelectronic applications, such as organic and perovskite solar cells. In this work, the films are fabricated using spin coating (a lab-scale method) and spray coating (an up-scalable method). The effects of spinning speed, drying time, and post-annealing temperature on spun-on samples and the effects of the substrate temperature and number of spray passes (deposition layers) on spray-on samples, as well as the effect of precursor solution concentration on both cases are investigated. Various characterization tools, such as AFM, SEM, XRD, confocal laser scanning microscopy (CLSM), and electrical conductivity measurements are used to determine the film roughness, thickness, structure, and morphology. The solution precursor physical data, such as contact angle on glass substrates, viscosity, and interfacial tension, are also obtained within a practical range of temperatures and concentrations. It is found that in both spin and spray coating routes, only well-controlled operating conditions result in the formation of conductive and defect-free PEDOT:PSS films. The formation of PEDOT:PSS thin films with small grains composed of PEDOT forming the core of the grains and PSS forming a shell or coating, which are evenly distributed in a PSS-rich matrix, is favored. Conditions leading to the above-mentioned electrically conductive scenario are identified. Other topics, such as the formation of defects and dewetting, are also elucidated.

  2. Piezoelectric immunochip coated with thin films of bacterial cellulose nanocrystals for dengue detection.

    PubMed

    Pirich, Cleverton Luiz; de Freitas, Rilton Alves; Torresi, Roberto Manuel; Picheth, Guilherme Fadel; Sierakowski, Maria Rita

    2017-06-15

    Low-cost piezoelectric devices, such as simple frequency monitoring quartz crystal microbalance (QCM) devices, have good clinical utility as fast diagnostic tools for the detection of several diseases. However, unspecific antigen recognition, poor molecular probe adsorption and the need for sample dilution are still common drawbacks that hinder their use in routine diagnosis. In this work, piezoelectric sensors were previously coated with thin films of bacterial cellulose nanocrystals (CN) to provide a more sensitive and adapted interface for the attachment of monoclonal immunoglobulin G (IgGNS1) and to favor specific detection of non-structural protein 1 (NS1) of dengue fever. The assembly of the immunochip surface was analyzed by atomic force microscopy (AFM) and the NS1 detection was followed by quartz crystal microbalance with (QCM-D) and without energy dissipation monitoring (QCM). The CN surface was able to immobilize 2.30±0.5mgm(-2) of IgGNS1, as confirmed by AFM topography and phase images along with QCM-D. The system was able to detect the NS1 protein in serum with only 10-fold dilution in the range of 0.01-10µgmL(-1) by both QCM and QCM-D. The limits of detection of the two devices were 0.1μgmL(-1) for QCM-D and 0.32μgmL(-1) for QCM. As a result, QCM-D and QCM apparatuses can be used to follow NS1 recognition and have good potential for more sensitive, fast and/or less expensive diagnostic assays for dengue.

  3. Throughput of Ultraviolet Nanoimprint in Pentafluoropropane Using Spin Coat Films under Thin Residual Layer Conditions

    NASA Astrophysics Data System (ADS)

    Hiroshima, Hiroshi; Suzuki, Kenta

    2012-06-01

    In UV nanoimprint, UV-curable resin is usually supplied as droplets, but, from the viewpoint of throughput, it is not the best approach in some cases. When the pattern density of a given layout can be regarded as uniform, UV-curable resin should be supplied as a film with a uniform thickness if no other critical problems occur. Fine line-and-space (L/S) patterns with widths of 45, 65, and 90 nm were successfully fabricated with a residual layer thickness of 20 nm by UV-NIL in pentafluoropropane (PFP) using a spin coat UV-curable resin, PAK-01, and the throughput of UV-NIL in PFP for the fabrication of such fine L/S patterns with a thin residual layer was investigated. The resin filling of UV-NIL in air was not completed in 15 s but that of UV-NIL in PFP was completed in 0.6 s. The filling speed of UV-NIL in PFP is 80 times higher than that of UV-NIL in air. This value is one order of magnitude larger for the fabrication of patterns with a width of 300 µm in our previous work, and the high-throughput process is presumably due to the large capillary pressure, which may be canceled out for UV-NIL in air, of fine grooves of the L/S patterns. Simulation revealed that a virtual imprint pressure of 2.2 MPa should be produced by the capillary pressure for UV-NIL in PFP. Simulations also revealed that the complete filling time is proportional to the square of the space width and that the resin filling would be completed in 0.1 s for a space width of less than 40 µm.

  4. Biphasic water splitting by osmocene

    PubMed Central

    Ge, Peiyu; Todorova, Tanya K.; Patir, Imren Hatay; Olaya, Astrid J.; Vrubel, Heron; Mendez, Manuel; Hu, Xile; Corminboeuf, Clémence; Girault, Hubert H.

    2012-01-01

    The photochemical reactivity of osmocene in a biphasic water-organic solvent system has been investigated to probe its water splitting properties. The photoreduction of aqueous protons to hydrogen under anaerobic conditions induced by osmocene dissolved in 1,2-dichloroethane and the subsequent water splitting by the osmocenium metal-metal dimer formed during H2 production were studied by electrochemical methods, UV-visible spectrometry, gas chromatography, and nuclear magnetic resonance spectroscopy. Density functional theory computations were used to validate the reaction pathways. PMID:22665787

  5. Thin-film metal coated insulation barrier in a Josephson tunnel junction. [Patent application

    DOEpatents

    Hawkins, G.A.; Clarke, J.

    1975-10-31

    A highly stable, durable, and reproducible Josephson tunnel junction consists of a thin-film electrode of a hard superconductor, a thin oxide insulation layer over the electrode constituting a Josephson tunnel junction barrier, a thin-film layer of stabilizing metal over the barrier, and a second thin-film hard superconductive electrode over the stabilizing film. The thin stabilizing metal film is made only thick enough to limit penetration of the electrode material through the insulation layer so as to prevent a superconductive short.

  6. Examination of the influence of coatings on thin superalloy sections. Volume 1: Description and analysis

    NASA Technical Reports Server (NTRS)

    Kaufman, M.

    1974-01-01

    The effects of an aluminide coating and of section thickness were investigated on two cast nickel-base superalloys. Cast section thickness ranged from 0.038 cm to 0.15 cm. Simulated engine exposures in a jet fuel burner rig with cyclic air cooling were studied. The effects of surface machining before coating and re-machining and re-coating after exposures were examined. The properties evaluated included tensile strength, stress rupture, high-cycle mechanical fatigue, and thermal fatigue. A metallurgical analysis was made of the microstructures of the coated and uncoated alloy.

  7. Engineering the microstructure and permeability of thin multilayer latex biocatalytic coatings containing E. coli.

    PubMed

    Lyngberg, O K; Ng, C P; Thiagarajan, V; Scriven, L E; Flickinger, M C

    2001-01-01

    The microstructure and permeability of rehydrated 20-100 microm thick partially coalesced (vinyl-actetate acrylic copolymer) SF091 latex coatings and a 118 microm thick model trilayer biocatalytic coating consisting of two sealant SF091 layers containing a middle layer of viable E. coli HB101 + latex were studied as delaminated films in a diffusion apparatus with KNO(3) as the diffussant. The permeability of the hydrated coatings is due to diffusive transport through the pore space between the partially coalesced SF091 latex particles. Coating microstructure was visualized by fast freeze cryogenic scanning electron microscopy (cryo-SEM). The effective diffusion coefficient of SF091 latex coatings (diffusive permeability/film thickness) was determined as the ratio of the effective diffusivity of KNO(3) to its diffusivity in water (D(eff)/D). Polymer particle coalescence was arrested by two methods to increase coating permeability. The first used glycerol with coating drying at 4 degrees C, near the glass transition temperature (T(g)). The second method used sucrose or trehalose as a filler to arrest coalescence; the filler was then dissolved away. D(eff)/D was measured as a function of film thickness; content of glycerol, sucrose, and trehalose; drying time; and rehydration time. D(eff)/D varied from 3 x 10(-4) for unmodified SF091 coatings to 6.8 x 10(-2) for coatings containing sucrose. D(eff)/D was reduced by the flattening of latex particles against the surface of the solid substrate, as well as by the presence of the colloid stabilizer hydroxyethylcellulose (HEC). When corrected for the flattened particle layer, D(eff)/D of HEC-free coatings was as high as 0.20, which agreed with the value predicted from analysis of cryo-SEM images of the coat surface. D(eff)/D decreased by one-half in approximately 5 days in rehydrated SF091 coatings, indicating that significant wet coalescence occurs after glycerol, sucrose, or trehalose are leached from the films. D

  8. Conformal coating of thin polymer electrolyte layer on nanostructured electrode materials for three-dimensional battery applications.

    PubMed

    Gowda, Sanketh R; Reddy, Arava Leela Mohana; Shaijumon, Manikoth M; Zhan, Xiaobo; Ci, Lijie; Ajayan, Pulickel M

    2011-01-12

    Various three-dimensional (3D) battery architectures have been proposed to address effective power delivery in micro/nanoscale devices and for increasing the stored energy per electrode footprint area. One step toward obtaining 3D configurations in batteries is the formation of core-shell nanowires that combines electrode and electrolyte materials. One of the major challenges however in creating such architectures has been the coating of conformal thin nanolayers of polymer electrolytes around nanostructured electrodes. Here we show conformal coatings of 25-30 nm poly(methyl methacralate) electrolyte layers around individual Ni-Sn nanowires used as anodes for Li ion battery. This configuration shows high discharge capacity and excellent capacity retention even at high rates over extended cycling, allowing for scalable increase in areal capacity with electrode thickness. Our results demonstrate conformal nanoscale anode-electrolyte architectures for an efficient Li ion battery system.

  9. Effect of substrate crystalline morphology on the adhesion of plasma enhanced chemical vapor deposited thin silicon oxide coatings on polyamide

    NASA Astrophysics Data System (ADS)

    Rochat, G.; Leterrier, Y.; Plummer, C. J. G.; Mânson, J.-A. E.; Szoszkiewicz, R.; Kulik, A. J.; Fayet, P.

    2004-05-01

    The influence of the surface morphology of semicrystalline polyamide 12 (PA12) on the adhesion of thin silicon oxide coatings is analyzed by means of uniaxial fragmentation tests and scanning local-acceleration microscopy (SLAM). Two types of PA12 substrates are investigated, namely, as-received PA12, which contains large spherulites, and quenched PA12, which has a relatively smooth, homogeneous surface structure. The adhesion of the coating is found to be identical for the two types of PA12. This indicates that plasma deposition of the oxide leads to an equivalent functionalization of the two types of surfaces. Nonetheless, localized delamination is observed at spherulite boundaries, and is argued to result from strain concentrations in the corresponding soft zones, revealed by SLAM measurements.

  10. Thin casein films as prepared by spin-coating: influence of film thickness and of pH.

    PubMed

    Müller-Buschbaum, P; Gebhardt, R; Maurer, E; Bauer, E; Gehrke, R; Doster, W

    2006-06-01

    Casein films were successfully prepared with the spin-coating technique of aqueous casein solutions on base-treated glass surfaces. The film structure is investigated in real space with optical microscopy and atomic force microscopy and for the first time in reciprocal space with grazing incidence small-angle X-ray scattering (GISAXS). The size of the substructures detected in the film increases with pH from 170 nm (pH 5.1) up to 490 nm (pH 9.4). Dynamic light scattering experiments reveal that the average diameters of casein micelles in solution exhibit the same quantitative increase. This result suggests that the substructures detected in the bulklike films with GISAXS reflect intact casein micelles. However, with thin homogeneous casein films, the micelle size diminishes with decreasing film thickness. This indicates that the moderate pressures introduced by spin-coating force the micelles to rearrange into a more compact structure.

  11. Application of thin-film interference coatings in infrared reflection spectroscopy of organic samples in contact with thin metal films.

    PubMed

    Reithmeier, Martina; Erbe, Andreas

    2011-03-20

    A thin dielectric IR-transparent interlayer is introduced between an IR-transparent medium of incidence and a thin metal film. The interlayer increases the intensity of light on the metal/sample interface at certain wavenumbers. By computations, the reflectivities of the system "calcium fluoride (CaF)-germanium (Ge)-gold (Au) sample" are analyzed as a function of incidence angle and Ge layer thickness. Absorbance spectra with acetonitrile as a sample are recorded for different angles of incidence and polarizations and compared to computations. A characteristic feature of the absorbance spectra is the occurrence of interference fringes distributed between 1000 and 6000 cm(-1), i.e., over the complete mid-IR wavelength range into the near-IR. These fringes could be used in analytical spectroscopy.

  12. Optical Gratings Coated with Thin Si3N4 Layer for Efficient Immunosensing by Optical Waveguide Lightmode Spectroscopy.

    PubMed

    Diéguez, Lorena; Caballero, David; Calderer, Josep; Moreno, Mauricio; Martínez, Elena; Samitier, Josep

    2012-04-10

    New silicon nitride coated optical gratings were tested by means of Optical Waveguide Lightmode Spectroscopy (OWLS). A thin layer of 10 nm of transparent silicon nitride was deposited on commercial optical gratings by means of sputtering. The quality of the layer was tested by x-ray photoelectron spectroscopy and atomic force microscopy. As a proof of concept, the sensors were successfully tested with OWLS by monitoring the concentration dependence on the detection of an antibody-protein pair. The potential of the Si3N4 as functional layer in a real-time biosensor opens new ways for the integration of optical waveguides with microelectronics.

  13. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study.

    PubMed

    Sapsanis, Christos; Omran, Hesham; Chernikova, Valeriya; Shekhah, Osama; Belmabkhout, Youssef; Buttner, Ulrich; Eddaoudi, Mohamed; Salama, Khaled N

    2015-07-24

    A prototypical metal-organic framework (MOF), a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc) ligands (Cu(bdc)·xH2O), was grown successfully as a thin film on interdigitated electrodes (IDEs). IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs). Accordingly, the resultant IDEs coated with the Cu(bdc)·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance.

  14. Zeolite thin film-coated spherical end-face fiber sensors for detection of trace organic vapors

    NASA Astrophysics Data System (ADS)

    Ning, Xiangping; Zhao, Chun Liu; Yang, Jingyi; Chan, Chi Chiu

    2016-04-01

    A novel zeolite thin film-coated spherical end face fiber sensor for detection of trace organic vapors was experimentally demonstrated. The spherical end-face was fabricated by electrical arc discharge on the end face of a standard single-mode fiber. The proposed sensor comprise of the fiber's spherical end-face covered with a layer of zeolite thin film. The zeolite film and spherical end face constituted an arc-shaped inline Fabry-Perot (F-P) cavity, which improves the interference performance. The trace chemical vapor concentration was measured by monitoring the shift of F-P interference wavelength which induced by the organic vapor molecular adsorption of the zeolite film. The proposed trace organic vapors sensor performed with the enhanced sensitivity 0.91 nm/ppm with the range from 0 to 70 ppm.

  15. Upper Threshold Fields of Dendritic Flux Jumps in Gold-Coated MgB2 Thin Films

    NASA Astrophysics Data System (ADS)

    Choi, Eun-Mi; Lee, Hyun-Sook; Lee, Jae Yeap; Lee, Sung-Ik; Olsen, Å. A. F.; Yurchenko, V. V.; Shantsev, D. V.; Johansen, T. H.; Kim, Hyeong-Jin; Cho, Moo-Hyun

    We measured the magneto-optical images (MOIs) and the magnetic hysteresis (M - H) curves of c-axis-oriented MgB2 thin films to investigate the flux penetration in the form of dendritic avalanches. In order to understand the role of the thermal effects, we prepared Au-coated MgB2 thin films with different thicknesses of gold. While the MOI provides a spatially resolved flux pattern, the M - H curve presents global and average information about the flux noise associated with avalanches. These two types of measurements complement each other. The upper threshold field, above which the flux noise disappears, was determined from the M-H curves while the lower threshold field was determined from both the M - H curves and the MO images. The field range where the flux penetrates via avalanches is found to be smaller for thicker gold layers. These results are important for many superconducting applications.

  16. Study on fabrication of TiO2 thin films by spin - coating and their optical properties

    NASA Astrophysics Data System (ADS)

    Zharvan, Vicran; Daniyati, Risqa; Nur Ichzan A., S.; Yudoyono, Gatut; Darminto

    2016-03-01

    Study on fabrication of TiO2 thin films and their optical properties in UV-VIS spectrum has been conducted. TiO2 nanopowders were prepared by co-precipitation method with varying mixing duration for 5, 10 and 25 hours using TiCl3 as precursor. The as-synthesized TiO2 phase is anatase having crystalline size of 14.25 nm, 13.75 nm and 12.62, respectively for the corresponding mixing duration. Thin films of TiO2 were fabricated by spin coating method and then checked by XRD diffractometer and UV-Vis Spectrophotometer to examine their structure and band gap energy. The prepared films also contain anatase phase of TiO2 with respective band gap of 3.70 eV, 3.74 eV and 3.76 eV, depending on the powders and their treatment.

  17. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study

    PubMed Central

    Sapsanis, Christos; Omran, Hesham; Chernikova, Valeriya; Shekhah, Osama; Belmabkhout, Youssef; Buttner, Ulrich; Eddaoudi, Mohamed; Salama, Khaled N.

    2015-01-01

    A prototypical metal-organic framework (MOF), a 2D periodic porous structure based on the assembly of copper ions and benzene dicarboxylate (bdc) ligands (Cu(bdc)·xH2O), was grown successfully as a thin film on interdigitated electrodes (IDEs). IDEs have been used for achieving planar CMOS-compatible low-cost capacitive sensing structures for the detection of humidity and volatile organic compounds (VOCs). Accordingly, the resultant IDEs coated with the Cu(bdc)·xH2O thin film was evaluated, for the first time, as a capacitive sensor for gas sensing applications. A fully automated setup, using LabVIEW interfaces to experiment conduction and data acquisition, was developed in order to measure the associated gas sensing performance. PMID:26213943

  18. Marine corrosion protective coatings of hexagonal boron nitride thin films on stainless steel.

    PubMed

    Husain, Esam; Narayanan, Tharangattu N; Taha-Tijerina, Jose Jaime; Vinod, Soumya; Vajtai, Robert; Ajayan, Pulickel M

    2013-05-22

    Recently, two-dimensional, layered materials such as graphene and hexagonal boron nitride (h-BN) have been identified as interesting materials for a range of applications. Here, we demonstrate the corrosion prevention applications of h-BN in marine coatings. The performance of h-BN/polymer hybrid coatings, applied on stainless steel, were evaluated using electrochemical techniques in simulated seawater media [marine media]. h-BN/polymer coating shows an efficient corrosion protection with a low corrosion current density of 5.14 × 10(-8) A/cm(2) and corrosion rate of 1.19 × 10(-3) mm/year and it is attributed to the hydrofobic, inert and dielectric nature of boron nitride. The results indicated that the stainless steel with coatings exhibited improved corrosion resistance. Electrochemical impedance spectroscopy and potentiodynamic analysis were used to propose a mechanism for the increased corrosion resistance of h-BN coatings.

  19. Method for repair of thin glass coatings. [on space shuttle orbiter tiles

    NASA Technical Reports Server (NTRS)

    Holt, J. W.; Helman, D. D.; Smiser, L. W.

    1982-01-01

    A method of repairing cracks or damaged areas in glass, in particular, glass coatings provided on tile. The method includes removing the damaged area using a high speed diamond burr drilling out a cavity that extends slightly into the base material of the tile. All loose material is then cleaned from the drilled out cavity and the cavity is filled adjacent the upper surface of the coating with a filler material including chopped silica fibers mixed with a binder. The filler material is packed into the cavity and a repair coating is applied by means of a brush or sprayed thereover. The repair includes borosilicate suspended in solution. Heat is applied at approximately 2100 F. for approximately five minutes for curing the coating, causing boron silicide particles of the coating to oxidize forming a very fluid boron-oxide rich glass which reacts with the other frits to form an impervious, highly refractory layer.

  20. PVC-plasticizer DEHP in medical products: do thin coatings really reduce DEHP leaching into blood?

    PubMed

    Hildenbrand, Sibylle L; Lehmann, Hans-Dieter; Wodarz, Roman; Ziemer, Gerhard; Wendel, Hans P

    2005-10-01

    The hemocompatibility of artificial surfaces in extracorporeal blood circulation systems can be improved by coatings. According to the literature, heparin coatings should avoid the leaching of the plasticizer di(2-ethylhexyl) phthalate (DEHP) into the blood from components made from plasticized polyvinyl chloride (PVC). DEHP and its metabolites are known to impair the fertility of male rodents; effects on human fertility are assumed. Three different surface coatings with and without heparin were examined in a Chandler Loop model at 37 degrees C using fresh human blood to evaluate their hemocompatibility and barrier property to plasticizer. The levels of toxic oxidation products of DEHP generated in the blood, particularly, were found as high as in the uncoated tubing. The coatings improved the hemocompatibility, but are not safe protection against the hazardous metabolites of DEHP. For pregnant women, neonates and children, we would recommend using the available surface-coated plasticized PVC tubing sets, but free of DEHP.

  1. Electrical and optical properties of p-type codoped ZnO thin films prepared by spin coating technique

    NASA Astrophysics Data System (ADS)

    Pathak, Trilok Kumar; Kumar, Vinod; Swart, H. C.; Purohit, L. P.

    2016-03-01

    Undoped, doped and codoped ZnO thin films were synthesized on glass substrates using a spin coating technique. Zinc acetate dihydrate, ammonium acetate and aluminum nitrate were used as precursor for zinc, nitrogen and aluminum, respectively. X-ray diffraction shows that the thin films have a hexagonal wurtzite structure for the undoped, doped and co-doped ZnO. The transmittance of the films was above 80% and the band gap of the film varied from 3.20 eV to 3.24 eV for undoped and doped ZnO. An energy band diagram to describe the photoluminescence from the thin films was also constructed. This diagram includes the various defect levels and possible quasi-Fermi levels. A minimum resistivity of 0.0834 Ω-cm was obtained for the N and Al codoped ZnO thin films with p-type carrier conductivity. These ZnO films can be used as a window layer in solar cells and in UV lasers.

  2. Gd doping effect on structural, electrical and magnetic properties of ZnO thin films synthesized by sol-gel spin coating technique

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjeev; Thangavel, Rajalingam

    2017-03-01

    Nanocrystalline Gd-doped ZnO thin films were deposited on sapphire (0001) substrates using sol-gel spin coating technique. The structural and optical properties of deposited thin films were characterized by X-ray diffraction (XRD) and micro Raman spectroscopy. Structural and optical studies show that the doped Gd ions occupy Zn sites retaining the wurtzite symmetry. Photoluminescence (PL) studies reveal the presence of oxygen vacancies in Gd doped ZnO thin films. The resistivity of Gd doped ZnO thin film decreases with increase in Gd doping upto 4%. Gd-doped ZnO films demonstrate weak magnetic ordering at room temperature.

  3. Substrate-Independent Robust and Heparin-Mimetic Hydrogel Thin Film Coating via Combined LbL Self-Assembly and Mussel-Inspired Post-Cross-linking.

    PubMed

    Ma, Lang; Cheng, Chong; He, Chao; Nie, Chuanxiong; Deng, Jie; Sun, Shudong; Zhao, Changsheng

    2015-12-02

    In this work, we designed a robust and heparin-mimetic hydrogel thin film coating via combined layer-by-layer (LbL) self-assembly and mussel-inspired post-cross-linking. Dopamine-grafted heparin-like/-mimetic polymers (DA-g-HepLP) with abundant carboxylic and sulfonic groups were synthesized by the conjugation of adhesive molecule, DA, which exhibited substrate-independent adhesive affinity to various solid surfaces because of the formation of irreversible covalent bonds. The hydrogel thin film coated substrates were prepared by a three-step reaction: First, the substrates were coated with DA-g-HepLP to generate negatively charged surfaces. Then, multilayers were obtained via LbL coating of chitosan and the DA-g-HepLP. Finally, the noncovalent multilayers were oxidatively cross-linked by NaIO4. Surface ATR-FTIR and XPS spectra confirmed the successful fabrication of the hydrogel thin film coatings onto membrane substrates; SEM images revealed that the substrate-independent coatings owned 3D porous morphology. The soaking tests in highly alkaline, acid, and concentrated salt solutions indicated that the cross-linked hydrogel thin film coatings owned high chemical resistance. In comparison, the soaking tests in physiological solution indicated that the cross-linked hydrogel coatings owned excellent long-term stability. The live/dead cell staining and morphology observations of the adhered cells revealed that the heparin-mimetic hydrogel thin film coated substrates had low cell toxicity and high promotion ability for cell proliferation. Furthermore, systematic in vitro investigations of protein adsorption, platelet adhesion, blood clotting, and blood-related complement activation confirmed that the hydrogel film coated substrates showed excellent hemocompatibility. Both the results of inhibition zone and bactericidal activity indicated that the gentamycin sulfate loaded hydrogel thin films had significant inhibition capability toward both Escherichia coli and

  4. Hydrophobic coating of solid materials by plasma-polymerized thin film using tetrafluoroethylene

    NASA Technical Reports Server (NTRS)

    Hozumi, K.; Kitamura, K.; Kitade, T.

    1980-01-01

    Glass slides were coated with plasma-polymerized tetrafluoroethylene films of different thickness using the glow discharge technique in a tube-shaped chamber, and the plasma conditions, film growth rates, light permeability of the polymer films, and particle bond strength in the polymer films were studied. Ashed sections of mouse organs and ashed bacillus spores were also coated to give them hydrophobic treatment without damaging their shapes or appearance. The hydrophobic coating of the specimens was successful, and the fine ash patterns were strongly fixed onto the glass slides, making permanent preparations.

  5. Acoustoelectric Effect on the Responses of SAW Sensors Coated with Electrospun ZnO Nanostructured Thin Film

    PubMed Central

    Tasaltin, Cihat; Ebeoglu, Mehmet Ali; Ozturk, Zafer Ziya

    2012-01-01

    In this study, zinc oxide (ZnO) was a very good candidate for improving the sensitivity of gas sensor technology. The preparation of an electrospun ZnO nanostructured thin film on a 433 MHz Rayleigh wave based Surface Acoustic Wave (SAW) sensor and the investigation of the acoustoelectric effect on the responses of the SAW sensor are reported. We prepared an electrospun ZnO nanostructured thin film on the SAW devices by using an electrospray technique. To investigate the dependency of the sensor response on the structure and the number of the ZnO nanoparticles, SAW sensors were prepared with different coating loads. The coating frequency shifts were adjusted to fall between 100 kHz and 2.4 MHz. The sensor measurements were performed against VOCs such as acetone, trichloroethylene, chloroform, ethanol, n-propanol and methanol vapor. The sensor responses of n-propanol have opposite characteristics to the other VOCs, and we attributed these characteristics to the elastic effect/acoustoelectric effect.

  6. Hydroxyapatite coatings on nanotubular titanium dioxide thin films prepared by radio frequency magnetron sputtering.

    PubMed

    Shin, Jinho; Lee, Kwangmin; Koh, Jeongtae; Son, Hyeju; Kim, Hyunseung; Lim, Hyun-Pil; Yun, Kwidug; Oh, Gyejeong; Lee, Seokwoo; Oh, Heekyun; Lee, Kyungku; Hwang, Gabwoon; Park, Sang-Won

    2013-08-01

    In this study, hydroxyapatite (HA) was coated on anodized titanium (Ti) surfaces through radio frequency magnetron sputtering in order to improve biological response of the titanium surface. All the samples were blasted with resorbable blasting media (RBM). RBM-blasted Ti surface, anodized Ti surface, as-sputtered HA coating on the anodized Ti surface, and heat-treated HA coating on the anodized Ti surface were prepared. The samples were characterized using scanning electron microscopy and X-ray photoemission spectroscopy, and biologic responses were evaluated. The top of the TiO2 nanotubes was not closed by HA particles when the coating time is less than 15 minutes. It was demonstrated that the heat-treated HA was well-crystallized and this enhanced the cell attachment of the anodized Ti surface.

  7. Fly ash based geopolymer thin coatings on metal substrates and its thermal evaluation.

    PubMed

    Temuujin, Jadambaa; Minjigmaa, Amgalan; Rickard, William; Lee, Melissa; Williams, Iestyn; van Riessen, Arie

    2010-08-15

    Class F fly ash based Na-geopolymer formulations have been applied as fire resistant coatings on steel. The main variables for the coating formulations were Si: Al molar and water: cement weight ratios. We have determined that the adhesive strength of the coatings strongly depend on geopolymer composition. The ease with which geopolymer can be applied onto metal surfaces and the resultant thickness depend on the water content of the formulation. Adhesive strengths of greater than 3.5 MPa have been achieved on mild steel surfaces for compositions with Si:Al of 3.5. Microstructure evolution and thermal properties of the optimised coating formulations show that they have very promising fire resistant characteristics.

  8. Evaluation of an Innovative Use of Removable Thin Film Coating Technology for the Abatement of Hazardous Contaminants

    PubMed Central

    Lumia, Margaret E.; Gentile, Charles; Gochfeld, Michael; Efthimion, Philip; Robson, Mark

    2015-01-01

    This study evaluates a new decontamination technique for the mitigation and abatement of hazardous particulates. The traditional decontamination methods used to clean facilities and equipment are time-consuming, prolonging workers' exposure time, may generate airborne hazards, and can be expensive. The use of removable thin film coating as a decontamination technique for surface contamination proved to be a more efficient method of decontamination. This method was tested at three different sites on different hazardous metals. One application of the coating reduced the levels of these metals 90% and had an average reduction of one magnitude. The paired t-tests that were performed for each metal demonstrated that there was a statistically significant reduction of the metal after the use of the coating: lead (p = 0.03), beryllium (p = 0.05), aluminum (p = 0.006), iron (p = 0.0001), and copper (p = 0.004). The Kendall tau-b correlation coefficient demonstrates that there was a positive correlation between the initial levels of contamination and the removal efficiency for all the samples taken from different locations on the floor for each of the three sites. This new decontamination technique worked efficiently, requiring only one application, which decreased exposure time and did not generate any airborne dust. PMID:19437305

  9. Employing Synergetic Effect of Doping and Thin Film Coating to Boost the Performance of Lithium-Ion Battery Cathode Particles.

    PubMed

    Patel, Rajankumar L; Jiang, Ying-Bing; Choudhury, Amitava; Liang, Xinhua

    2016-05-04

    Atomic layer deposition (ALD) has evolved as an important technique to coat conformal protective thin films on cathode and anode particles of lithium ion batteries to enhance their electrochemical performance. Coating a conformal, conductive and optimal ultrathin film on cathode particles has significantly increased the capacity retention and cycle life as demonstrated in our previous work. In this work, we have unearthed the synergetic effect of electrochemically active iron oxide films coating and partial doping of iron on LiMn1.5Ni0.5O4 (LMNO) particles. The ionic Fe penetrates into the lattice structure of LMNO during the ALD process. After the structural defects were saturated, the iron started participating in formation of ultrathin oxide films on LMNO particle surface. Owing to the conductive nature of iron oxide films, with an optimal film thickness of ~0.6 nm, the initial capacity improved by ~25% at room temperature and by ~26% at an elevated temperature of 55 °C at a 1C cycling rate. The synergy of doping of LMNO with iron combined with the conductive and protective nature of the optimal iron oxide film led to a high capacity retention (~93% at room temperature and ~91% at 55 °C) even after 1,000 cycles at a 1C cycling rate.

  10. Employing Synergetic Effect of Doping and Thin Film Coating to Boost the Performance of Lithium-Ion Battery Cathode Particles

    NASA Astrophysics Data System (ADS)

    Patel, Rajankumar L.; Jiang, Ying-Bing; Choudhury, Amitava; Liang, Xinhua

    2016-05-01

    Atomic layer deposition (ALD) has evolved as an important technique to coat conformal protective thin films on cathode and anode particles of lithium ion batteries to enhance their electrochemical performance. Coating a conformal, conductive and optimal ultrathin film on cathode particles has significantly increased the capacity retention and cycle life as demonstrated in our previous work. In this work, we have unearthed the synergetic effect of electrochemically active iron oxide films coating and partial doping of iron on LiMn1.5Ni0.5O4 (LMNO) particles. The ionic Fe penetrates into the lattice structure of LMNO during the ALD process. After the structural defects were saturated, the iron started participating in formation of ultrathin oxide films on LMNO particle surface. Owing to the conductive nature of iron oxide films, with an optimal film thickness of ~0.6 nm, the initial capacity improved by ~25% at room temperature and by ~26% at an elevated temperature of 55 °C at a 1C cycling rate. The synergy of doping of LMNO with iron combined with the conductive and protective nature of the optimal iron oxide film led to a high capacity retention (~93% at room temperature and ~91% at 55 °C) even after 1,000 cycles at a 1C cycling rate.

  11. Effect of Magnesium and Osteoblast Cell Presence on Hydroxyapatite Formation on (Ti,Mg)N Thin Film Coatings

    NASA Astrophysics Data System (ADS)

    Onder, Sakip; Calikoglu-Koyuncu, Ayse Ceren; Torun Kose, Gamze; Kazmanli, Kursat; Kok, Fatma Nese; Urgen, Mustafa

    2016-07-01

    TiN and (Ti,Mg)N thin film coatings were deposited on Ti substrates by an arc-physical vapor deposition technique. The effect of cell presence on hydroxyapatite (HA) formation was investigated using surfaces with four different Mg contents (0, 8.1, 11.31, and 28.49 at.%). Accelerated corrosion above 10 at.% Mg had a negative effect on the performance in terms of both cell proliferation and mineralization. In the absence of cells, Mg-free TiN coatings and low-Mg (8.1 at.%)-doped (Ti,Mg)N surfaces led to an early HA deposition (after 7 days and 14 days, respectively) in cell culture medium (DMEM), but the crystallinity was low. More crystalline HA structures were obtained in the presence of the cells. HA deposits with an ideal Ca/P ratio were obtained at least a week earlier, at day 14, in TiN and low-Mg (8.1 at.%)-doped (Ti,Mg)N compared with that of high-Mg-containing surfaces (>10 at.%). A thicker mineralized matrix was formed on low-Mg (8.1 at.%)-doped (Ti,Mg)N relative to that of the TiN sample. Low-Mg doping (<10 at.%) into TiN coatings resulted in better cell proliferation and thicker mineralized matrix formation, so it could be a promising alternative for hard tissue applications.

  12. Employing Synergetic Effect of Doping and Thin Film Coating to Boost the Performance of Lithium-Ion Battery Cathode Particles

    PubMed Central

    Patel, Rajankumar L.; Jiang, Ying-Bing; Choudhury, Amitava; Liang, Xinhua

    2016-01-01

    Atomic layer deposition (ALD) has evolved as an important technique to coat conformal protective thin films on cathode and anode particles of lithium ion batteries to enhance their electrochemical performance. Coating a conformal, conductive and optimal ultrathin film on cathode particles has significantly increased the capacity retention and cycle life as demonstrated in our previous work. In this work, we have unearthed the synergetic effect of electrochemically active iron oxide films coating and partial doping of iron on LiMn1.5Ni0.5O4 (LMNO) particles. The ionic Fe penetrates into the lattice structure of LMNO during the ALD process. After the structural defects were saturated, the iron started participating in formation of ultrathin oxide films on LMNO particle surface. Owing to the conductive nature of iron oxide films, with an optimal film thickness of ~0.6 nm, the initial capacity improved by ~25% at room temperature and by ~26% at an elevated temperature of 55 °C at a 1C cycling rate. The synergy of doping of LMNO with iron combined with the conductive and protective nature of the optimal iron oxide film led to a high capacity retention (~93% at room temperature and ~91% at 55 °C) even after 1,000 cycles at a 1C cycling rate. PMID:27142704

  13. Theory of Hydrostatic Lubrication for Like Charge Polymer Hydrogel Coated and Cartilage Coated Surfaces

    NASA Astrophysics Data System (ADS)

    Sokoloff, Jeffrey

    2011-03-01

    Polysaccharides hydrogels provide excellent lubrication of tissues and organs in humans and animals. It is argued on the basis of a solution of the Poisson-Boltzmann equation and scaling arguments that most asperities in ``contact'' at the interface between two hydrogel coated surfaces should be separated by a thin fluid layer, which is held in place by ion osmotic pressure. It is likely to be responsible for the excellent lubricating of these hydrogels. Although it appears that the same mechanism should operate in cartilage coated surfaces, it turns out that the friction coefficient is two orders of magnitude larger once equilibrium is established. A model will be provided which combines the biphasic model, traditionally used to explain the time dependence of the friction coefficient for two cartilage surfaces in contact , and the ion osmotic pressure mechanism used to explain the very low equilibrium friction coefficient for hydrogel interfaces.

  14. Spatially Uniform Thin-Film Formation of Polymeric Organic Semiconductors on Lyophobic Gate Insulator Surfaces by Self-Assisted Flow-Coating.

    PubMed

    Bulgarevich, Kirill; Sakamoto, Kenji; Minari, Takeo; Yasuda, Takeshi; Miki, Kazushi

    2017-02-22

    Surface hydrophobization by self-assembled monolayer formation is a powerful technique for improving the performance of organic field-effect transistors (OFETs). However, organic thin-film formation on such a surface by solution processing often fails due to the repellent property of the surface against common organic solvents. Here, a scalable unidirectional coating technique that can solve this problem, named self-assisted flow-coating, is reported. Producing a specially designed lyophobic-lyophilic pattern on the lyophobic surface enables organic thin-film formation in the lyophobic surface areas by flow-coating. To demonstrate the usefulness of this technique, OFET arrays with an active layer of poly(2,5-bis(3-hexadecylthiophene-2-yl)thieno[3,2-b]thiophene) are fabricated. The ideal transfer curves without hysteresis behavior are obtained for all OFETs. The average field-effect hole mobility in the saturation regime is 0.273 and 0.221 cm(2)·V(-1)·s(-1) for the OFETs with the channels parallel and perpendicular to the flow-coating direction, respectively, and the device-to-device variation is less than 3% for each OFET set. Very small device-to-device variation is also obtained for the on-state current, threshold voltage, and subthreshold swing. These results indicate that the self-assisted flow-coating is a promising coating technique to form spatially uniform thin films of polymeric organic semiconductors on lyophobic gate insulator surfaces.

  15. Optimal structure of light trapping in thin-film solar cells: dielectric nanoparticles or multilayer antireflection coatings?

    PubMed

    Zhao, Yongxiang; Chen, Fei; Shen, Qiang; Zhang, Lianmeng

    2014-08-10

    Recent research has found an alternative way to enhance light trapping of thin-film solar cells by using dielectric nanoparticles deposited on the cell surface. To improve the performance of light trapping, a systematic study on the influence of dielectric nanoparticles on enhancement efficiency is performed in this paper. We prove that the optimal dielectric nanoparticles are substantially equivalent to the multilayer antireflection coatings (ARCs) with a "low-high-low" dielectric constant profile. Moreover, it is demonstrated that the use of a simple two-layer SiO2/SiC ARC can reach 34.15% enhancement, which has exceeded the ideal limit of 32% of nanoparticles structure including plasmonic Ag nanoparticles, dielectric SiC, and TiO2 nanoparticles. That means the optimal multilayer ARCs structure is obviously superior to the optimal dielectric nanoparticles structure, and the deposition of a simple two-layer SiO2/SiC structure on top of a thin-film silicon solar cell can significantly enhance photoelectron generation and hence, result in superior performance of thin-film solar cells.

  16. Optical enhancement of Au doped ZrO2 thin films by sol-gel dip coating method

    NASA Astrophysics Data System (ADS)

    John Berlin, I.; Joy, K.

    2015-01-01

    Homogeneous and transparent Au doped ZrO2 thin films were prepared by sol-gel dip coating method. The films have mixed phase of tetragonal, monoclinic and face centered cubic with crack free surface. Due to the increase in Au doping concentration many-body interaction occurs between free carriers and ionized impurities causing decrease in optical band gap from 5.72 to 5.40 eV. Localized surface plasmon resonance peak of the Au doped films appeared at 610 nm. Conversion of photons to surface plasmons allows the sub-wavelength manipulation of electromagnetic radiation. Hence the prepared Au doped ZrO2 thin films can be applied in nanoscale photonic devices such as lenses, switches, waveguides etc. Moreover the photoluminescence (PL) intensity of Au doped ZrO2 thin films decrease due to decrease in the radiative recombination, life time of the excitons and suppression of grain growth of ZrO2 with increasing Au dopant.

  17. Annealing effect of double dip coated ZnAl2O4 thin films

    NASA Astrophysics Data System (ADS)

    Chandramohan, R.; Dhanasekaran, V.; Sundaram, K.; Mahalingam, T.

    2013-02-01

    Thin films of ZnAl2O4 were prepared by dip technique involving chemical solutions. Investigations on the effect of post heat treatment on the structural, optical properties of ZnAl2O4 thin films were studied and reported. Xray diffraction patterns revealed that the thin films are polycrystalline cubic structure of ZnAl2O4. The microstructural properties of ZnAl2O4 thin films were calculated and crystallite size tends to increase with increase of annealing temperatures. The texture coefficients have been evaluated and found to be greater than unity revealing high texturing of the architecture of the film. The optical band gap values were found to be in the range of 3.48 - 3.62 eV. The n and k were found to decrease with increase of post annealing temperature. The SEM revealed the uniform distribution of spherical grains.

  18. Photoelectrochemical cell having photoanode with thin boron phosphide coating as a corrosion resistant layer

    DOEpatents

    Baughman, Richard J.; Ginley, David S.

    1984-01-01

    A surface prone to corrosion in corrosive environments is rendered anticorrosive by CVD growing a thin continuous film, e.g., having no detectable pinholes, thereon, of boron phosphide. In one embodiment, the film is semiconductive. In another aspect, the invention is an improved photoanode, and/or photoelectrochemical cell with a photoanode having a thin film of boron phosphide thereon rendering it anitcorrosive, and providing it with unexpectedly improved photoresponsive properties.

  19. Polymer-assisted conformal coating of TiO2 thin films

    NASA Astrophysics Data System (ADS)

    Gillman, E. S.; Costello, D.; Moreno, M.; Raspopin, A.; Kasica, R.; Chen, L.

    2010-08-01

    Conformal coating of nanofabricated structures with a high-index dielectric material is a common problem for a diverse set of integrated photonic and plasmonic devices such as planar waveguides, on-chip spectrometers, gratings, flat panel displays, optical sensors, and integrated optical devices. In this paper we were recently able to demonstrate an alternate method for conformally coating photonic nanostructures using a low cost, polymer-assisted deposition (PAD) process for the metal-oxide TiO2. In a PAD process a thermally curable, hybrid high refractive index polymer solution is spin-coated onto a substrate. The polymer controls the viscosity and binds the metal ions, resulting in a homogeneous distribution of the precursor in solution. When cured at elevated temperature, the hybrid polymer coating decomposes to form a metal oxide-rich film that has a high refractive index that conformally fills the voids in nanofabricated structures. The resulting films have refractive indices higher than 1.83 in the visible region and film thicknesses between 250-500 nm depending on the level of metal-oxide loading, cure temperature, and number of coatings.

  20. Investigation of non-quarter wave design on multilayer optical thin film coatings from a heat transfer point of view

    NASA Astrophysics Data System (ADS)

    Ocak, Mustafa; Sert, Cüneyt; Okutucu, Tuba Ö.

    2013-11-01

    In this study multilayer thin film optical coatings, which are indispensable parts of optical systems are investigated from a heat transfer point of view. Laser irradiation induced temperature distribution on a multilayer coating stack is obtained by discretizing the heat diffusion equation using the finite volume method. In order to obtain mathematical representation of the energy flow and Electric Field Intensity (EFI) through the stack, Maxwell equations are solved by using the commercial software MacLeod®. Laser energy, which is absorbed by the multilayer stack in terms of heat, is calculated as a function of space and time by using the computed EFI, coating materials' optical properties and Gaussian laser beam parameters. Computed heat load is used in the finite volume solver ANSYS FLUENT® through a user defined function. Temperature distribution on a 19 layer HR multilayer coating stack irradiated by 1064 nm laser beam are obtained for both quarter wave and non-quarter wave designed configurations. Results of numerical simulations show that maximum temperature rise is seen in the first high index layer for quarter wave design (QWD). In addition to that, high temperatures are also seen in film/film interfaces, which is associated to both EFI distribution on the stack and wide differences in material properties between high and low index film layers. Non-quarter wave design (NQWD) is seen to be successful in decreasing temperatures at high index layers and at film/film interfaces. But it also changes the EFI distribution inside the multilayer stack, increasing absorbed laser energy and resulting in higher temperatures at modified low index layers.

  1. Thin magnesium layer confirmed as an antibacterial and biocompatible implant coating in a co‑culture model.

    PubMed

    Zaatreh, Sarah; Haffner, David; Strauss, Madlen; Dauben, Thomas; Zamponi, Christiane; Mittelmeier, Wolfram; Quandt, Eckhard; Kreikemeyer, Bernd; Bader, Rainer

    2017-04-01

    Implant-associated infections commonly result from biofilm‑forming bacteria and present severe complications in total joint arthroplasty. Therefore, there is a requirement for the development of biocompatible implant surfaces that prevent bacterial biofilm formation. The present study coated titanium samples with a thin, rapidly corroding layer of magnesium, which were subsequently investigated with respect to their antibacterial and cytotoxic surface properties using a Staphylococcus epidermidis (S. epidermidis) and human osteoblast (hOB) co‑culture model. Primary hOBs and S. epidermidis were co‑cultured on cylindrical titanium samples (Ti6Al4V) coated with pure magnesium via magnetron sputtering (5 µm thickness) for 7 days. Uncoated titanium test samples served as controls. Vital hOBs were identified by trypan blue staining at days 2 and 7. Planktonic S. epidermidis were quantified by counting the number of colony forming units (CFU). The quantification of biofilm‑bound S. epidermidis on the surfaces of test samples was performed by ultrasonic treatment and CFU counting at days 2 and 7. The number of planktonic and biofilm‑bound S. epidermidis on the magnesium‑coated samples decreased by four orders of magnitude when compared with the titanium control following 7 days of co‑culture. The number of vital hOBs on the magnesium‑coated samples was observed to increase (40,000 cells/ml) when compared with the controls (20,000 cells/ml). The results of the present study indicate that rapidly corroding magnesium‑coated titanium may be a viable coating material that possesses antibacterial and biocompatible properties. A co‑culture test is more rigorous than a monoculture study, as it accounts for confounding effects and assesses additional interactions that are more representative of in vivo situations. These results provide a foundation for the future testing of this type of surface in animals.

  2. Acute Biphasic Effects of Ayahuasca.

    PubMed

    Schenberg, Eduardo Ekman; Alexandre, João Felipe Morel; Filev, Renato; Cravo, Andre Mascioli; Sato, João Ricardo; Muthukumaraswamy, Suresh D; Yonamine, Maurício; Waguespack, Marian; Lomnicka, Izabela; Barker, Steven A; da Silveira, Dartiu Xavier

    2015-01-01

    Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca's chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.

  3. Acute Biphasic Effects of Ayahuasca

    PubMed Central

    Schenberg, Eduardo Ekman; Alexandre, João Felipe Morel; Filev, Renato; Cravo, Andre Mascioli; Sato, João Ricardo; Muthukumaraswamy, Suresh D.; Yonamine, Maurício; Waguespack, Marian; Lomnicka, Izabela; Barker, Steven A.; da Silveira, Dartiu Xavier

    2015-01-01

    Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8–13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30–50 and 50–100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca’s chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered. PMID:26421727

  4. Uniform coating of TiO2 thin films on particles by rotating cylindrical PCVD reactor.

    PubMed

    Kim, Dong-Joo; Baeg, Jin-Ook; Moon, Sang-Jin; Kim, Kyo-Seon

    2009-07-01

    We analyzed TiO2 thin film growth on glass particles in a rotating cylindrical plasma chemical vapor deposition (PCVD) reactor and numerically investigated the effects of several process variables on the film growth. An increase in titanium tetra-isopropoxide (TTIP) or O2 partial pressure can enhance the film growth rate on the particles because the concentration of TiO(x), which is the main precursor for thin film growth, becomes higher in the reactor. As the particle diameter decreases, the TiO(x) concentration increases and the thin film on the particles grows more quickly. The neutral-radical reaction between TTIP and O radicals for TiO(x) generation in TTIP + O2 plasmas can be important to enhance the thin film growth rate on the particles. The growth rate of TiO2 film predicted in this study was 1 approximately 20 nm/min, which is in good agreement with the published experimental results. This study suggests that a uniform TiO2 thin film on particles can be obtained by using a rotating cylindrical PCVD reactor.

  5. Growth of long triisopropylsilylethynyl pentacene (TIPS-PEN) nanofibrils in a polymer thin film during spin-coating.

    PubMed

    Park, Minwoo; Min, Yuho; Lee, Yu-Jeong; Jeong, Unyong

    2014-03-01

    This study demonstrates the growth of long triisopropylsilyethynyl pentacene (TIPS-PEN) nanofibrils in a thin film of a crystalline polymer, poly(ε-caprolactone) (PCL). During spin-coating, TIPS-PEN molecules are locally extracted around the PCL grain boundaries and they crystallize into [010] direction forming long nanofibrils. Molecular weight of PCL and weight fraction (α) of TIPS-PEN in PCL matrix are key factors to the growth of nanofibrils. Long high-quality TIPS-PEN nanofibrils are obtained with high-molecular-weight PCL and at the α values in the range of 0.03-0.1. The long nanofibrils are used as an active layer in a field-effect organic transistor.

  6. Poly(ester sulphonic acid) coated mercury thin film electrodes: characterization and application in batch injection analysis stripping voltammetry of heavy metal ions.

    PubMed

    Brett, C M; Fungaro, D A

    2000-01-10

    Mercury-thin film electrodes coated with a thin film of poly(ester sulphonic acid) (PESA) have been investigated for application in the analysis of trace heavy metals by square wave anodic stripping voltammetry using the batch injection analysis (BIA) technique. Different polymer dispersion concentrations in water/acetone mixed solvent are investigated and are characterised by electrochemical impedance measurements on glassy carbon and on mercury film electrodes. The influence of electrolyte anion, acetate or nitrate, on polymer film properties is demonstrated, acetate buffer being shown to be preferable for stripping voltammetry applications. Although stripping currents are between 30 and 70% less at the coated than at bare mercury thin film electrodes, the influence of model surfactants on stripping response is shown to be very small. The effect of the composition of the modifier film dispersion on calibration plots is shown; however, detection limits of around 5 nM are found for all modified electrodes tested. This coated electrode is an alternative to Nafion-coated mercury thin film electrodes for the analysis of trace metals in complex matrices, particularly useful when there is a high concentration of non-ionic detergents.

  7. Effect of the polymer concentration on the Rayleigh-instability-type transformation in polymer thin films coated in the nanopores of anodic aluminum oxide templates.

    PubMed

    Tsai, Chia-Chan; Chen, Jiun-Tai

    2015-03-03

    We study the Rayleigh-instability-type transformation of polystyrene (PS) thin films coated in the nanopores of anodic aluminum oxide (AAO) templates. The PS thin films are fabricated using a solution-wetting method, in which the wall thicknesses are controlled by the concentrations of the polymer solutions and the diameters of the nanopores. By thermal annealing, the surfaces of the thin films undulate and the morphologies transform from nanotubes to Rayleigh-instability-induced nanostructures (short nanorods) and long nanorods. To understand the mechanism of the morphology transformation further, we construct the morphology diagrams by annealing the PS thin films at different temperatures and times. We observe that the morphology diagrams of the PS thin films prepared by different concentrations are similar, indicating that the transformation kinetics are not affected by the film thicknesses. The values of the undulation wavelengths, however, are controlled by the film thicknesses and the diameters of the nanopores.

  8. Method and apparatus for coating a patterned thin film on a substrate from a fluid source with continuous feed capability

    DOEpatents

    Burrows, Paul E.; Sapochak, Linda S.

    2009-09-22

    A method and apparatus for forming patterned coatings of thin film, non-polymerizable compounds on a substrate. A mixture of the non-polymerizable compound and a liquid carrier is pumped into the interior of a heated evaporation box having an internal temperature sufficient to convert substantially all of the non-polymerizable compound and liquid carrier to a gaseous form. The non-polymerizable compound and liquid carrier are then removed from the evaporation box via exit slit in the evaporation box. Adjacent to the exit slit, and maintained in a vacuum, is a first substrate upon which the non-polymerizable compound condenses. The first substrate is in motion, for example on a web roller, thereby allowing a continuous coating of the non-polymerizable compound to be applied to the first substrate. Once the non-polymerizable compound is applied to one side of the first substrate, an energy source is then directed toward the opposite side of the first substrate. In this manner, a portion of the non-polymerizable compound is removed from the first substrate. A second substrate is then provided adjacent to the first substrate, and the non-polymerizable compound is thereby transferred from the first substrate onto the second substrate. By repeatedly transferring portions of the non-polymerizable material from the first substrate to the second substrate in this manner, the thin film, non-polymerizable materials can be formed onto the second substrate in a predetermined pattern, and in a continuous and highly efficient process.

  9. Thermocapillary flow of thin Cu-water nanoliquid film during spin coating process

    NASA Astrophysics Data System (ADS)

    Maity, Susanta

    2017-01-01

    Unsteady flow of thin Cu-water nanoliquid film over a horizontal rotating disk is studied numerically using finite difference technique under the assumption of planar interface. It is also assumed that the disk is cooling axisymmetrically from below. The effects of the nanolayer thickness and nanoparticle radius are considered for investigation. It is found that the film thinning rate decreases with increase of the nanoparticle volume fraction. It is also found that thickness of liquid decreases with increase of the thermocapillary parameter. The results show that the rate of film thinning is more for the thermal conductivity model of Yu and Choi [47] compared to the model of Maxwell [46]. It is observed that the film thinning rate increases with increase of nanolayer thickness but it decreases with the nanoparticle radius. A curve R=R_c(z,t) in R-z plane is delineated along which temperature gradient T_z is zero and positive or negative according to RR_c respectively. Furthermore, it is shown that the region for T_z>0 enlarges with increase of the nanoparticle volume fraction and the nanolayer thickness.

  10. Optical properties and switching durability of TiO2 top-coated magnesium-nickel thin-film switchable mirrors

    NASA Astrophysics Data System (ADS)

    Bao, Shanhu; Zhang, Xiaoli; Jin, Ping; Yoshimura, Kazuki

    2015-04-01

    An amorphous TiO2 film (180 nm) was deposited as a protective layer on the surface of a triple-layer thin-film switchable mirror (Pd/Ti/Mg4Ni deposited on glass) by a sol-gel coating process, and its optical switching behavior and switching lifetime under 4% hydrogen gas loading were evaluated. The use of a TiO2 coating extended the switching durability to about 1600 cycles, which is a fourfold increase compared with that of uncoated mirrors. The switching response of the Pd/Ti/Mg4Ni thin film was not affected by the presence of the TiO2 film, with hydrogenation and dehydrogenation speeds being almost the same as those of uncoated mirrors. The optical properties of the TiO2-coated mirrors were improved in the hydrogenated state, and a diffuse reflection phenomenon was observed in the dehydrogenated state.

  11. Fabrication and characterization of 6,13-bis(triisopropylsilylethynyl)-pentacene active semiconductor thin films prepared by flow-coating method

    NASA Astrophysics Data System (ADS)

    Mohamad, Khairul Anuar; Rusnan, Fara Naila; Seria, Dzulfahmi Mohd Husin; Saad, Ismail; Alias, Afishah; Katsuhiro, Uesugi; Hisashi, Fukuda

    2015-08-01

    Investigation on the physical characterization and comparison of organic thin film based on a soluble 6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene is reported. Oriented thin-films of pentacene have been successfully deposited by flow-coating method, in which the chloroform solution is sandwiched between a transparent substrate and a slide glass, followed by slow-drawing of the substrate with respect to the slide glass. Molecular orientation of flow-coated TIPS-pentacene is comparable to that of the thermal-evaporated pentacene thin film by the X-ray diffraction (XRD) results. XRD results showed that the morphology of flow-coated soluble pentacene is similar to that of the thermal-evaporated pentacene thin films in series of (00l) diffraction peaks where the (001) diffraction peaks are strongest in the nominally out-of-plane intensity and interplanar spacing located at approximately 2θ = 5.33° (d-spacing, d001 = 16 Å). Following that, ITO/p-TIPS-pentacene/n-ZnO/Au vertical diode was fabricated. The diode exhibited almost linear characteristics at low voltage with nonlinear characteristics at higher voltage which similar to a pn junction behavior. The results indicated that the TIPS-pentacene semiconductor active thin films can be used as a hole injection layer for fabrication of a vertical organic transistor.

  12. Thin film fabrication of PMMA/MEH-PPV immiscible blends by corona discharge coating and its application to polymer light emitting diodes.

    PubMed

    Jung, Hee Joon; Park, Youn Jung; Choi, Sang Hun; Hong, Jae-Min; Huh, June; Cho, Jun Han; Kim, Jung Hyun; Park, Cheolmin

    2007-02-13

    We introduce a new and facile process, corona discharge coating (CDC), to fabricate thin polymer films of the immiscible poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) and poly(methyl methacrylate) (PMMA) blends. The method is based on utilizing directional electric flow, known as electric wind, of the charged unipolar particles generated by corona discharge between a metallic needle and a bottom plate under high electric field (5-10 kV/cm). The electric flow rapidly spreads out the polymer solution on the bottom plate and subsequently forms a smooth and flat thin film over a large area within a few seconds. The method is found to be effective for fabricating uniform thin polymer films with areas larger than approximately 30 mm2. The thin films obtained by CDC exhibit unique microstructures where well-defined spherical and cylindrical domains of approximately 50 nm in diameter coexist. These nanosized domains are found to be much smaller than those in films made by conventional spin coating, which suggests that CDC is beneficial for fabricating phase-separated thin film structures with significantly increased interfacial areas. The effects of the applied voltage, tip-to-plate distance, and substrates on the film formation as well as the resulting microstructure are investigated. Furthermore, the light emitting performance of a device prepared by CDC is compared with one made by spin coating.

  13. Optical and surface characterization of amorphous boron nitride thin films for use as blood compatible coatings

    NASA Astrophysics Data System (ADS)

    Lousinian, S.; Kalfagiannis, N.; Logothetidis, S.

    2009-10-01

    The aim of this work is the investigation of the haemocompatibility properties of homogeneous and amorphous boron nitride (a-BN) thin films, through the adsorption of two basic blood plasma proteins, human serum albumin (HSA) and fibrinogen (Fib). The a-BN thin films were grown onto c-Si(100) substrates under different values of substrate bias voltage, employing the radio frequency (RF) magnetron sputtering technique. For the consideration of the optical, compositional and structural properties of the films, Spectroscopic Ellipsometry (SE) in the Vis-UV spectral region was used, while for the study of surface topography and surface charge distribution as well as of the wetting properties of the a-BN thin films, Atomic Force Microscopy (AFM), Electric Force Microscopy (EFM) and Contact Angle measurements were additionally employed. The properties of the thin films were correlated with their haemocompatibility, through the estimation of the ratio of HSA/Fib surface concentration. The sp 3 content of the samples does not seem to correlate with the haemocompatibility of the a-BN thin films. However, the surface properties determine the thrombogenicity potential of the studied samples. More precisely, the a-BN films with a less negatively charged surface exhibit the smallest possibility of clot formation, possibly due to the interactions between the charged chains of the Fib molecules and the a-BN surface, while slight changes in the surface roughness do not affect their haemocompatibility properties. The wetting properties determine the thickness of the adsorbed Fib as well as the ratio of HSA/Fib surface concentration.

  14. Corrosion Protection Of Front Surface Aluminum Mirror Coatings With Dielectric Thin Films Deposited By Reactive Ion Plating

    NASA Astrophysics Data System (ADS)

    Guenther, Karl H.; Penny, Iain; Willey, Ronald R.

    1990-01-01

    Front surface metal mirrors need protection of the inherently fragile metal film normally deposited by evaporation in high vacuum. Dielectric thin films, also deposited by thermal or electron beam evaporation in high vacuum, provide limited protection because of their less than dense packing. These films usually have a columnar structure with voids between the columns. The voids give access to the metal film for humidity and corrosive gases or liquids. Sainty et al. [Appl. Opt. 23, 1116 (1984)] made some progress in developing better protective coatings with ion assisted deposition. We manufactured protected front surface aluminum mirrors using reactive ion plating deposition. When immersed in 0.2M NaOH, our best mirror survived for 20 hours while only degrading to a transmission of 10%, exceeding the results of Sainty et al. by a factor of 5 under the same test conditions. Electron beam evaporated dielectric coatings provided protection for about 1.5 to 2 hours in the same solution. We will discuss the reason for the significant improvement brought about by low voltage reactive ion plating deposition, and its advantage for large scale production.

  15. Large-area thin self-supporting carbon foils with MgO coatings

    NASA Astrophysics Data System (ADS)

    Stolarz, Anna; Maier-Komor, Peter

    2002-03-01

    Large area self-supporting carbon foils in the thickness of range of 8-22 μg/cm 2, coated with approximately 4 μg/cm 2 MgO have been prepared by e-gun evaporation. They were mounted on frames with apertures of 130 cm 2. Problems related to the parting agent preparation, floating procedure, and mounting onto frames are discussed. Special precautions necessary to avoid damage during foil drying, storage and transportation are suggested.

  16. Characterization of Ni-doped TiO2 thin films deposited by dip-coating technique

    NASA Astrophysics Data System (ADS)

    Kharoubi, Abdelmalek; Bouaza, A.; Benrabah, B.; Ammari, A.; Khiali, A.

    2015-12-01

    Undoped and Ni-doped TiO2 thin films have been prepared by sol-gel dip-coating method on glass and silicon substrates. X-ray diffraction studies show that both TiO2 and Ni-doped TiO2 thin films are of anatase phase with (1 0 1) as preferential orientation. From the UV-visible spectroscopy analysis, all films exhibits a high transparency ~ 80% and shows that the optical band gap decreases from 3.66 to 3.59 eV, which may be related with the phase composition and impurities. Fourier transformed infrared spectroscopy (FTIR) study confirms the presence of Ti-O, Ti=O and O-H bands. Thermal analysis by differential scanning calorimetriy (DSC) shows endothermic reactions between 30 °C and 280 °C and exothermic reactions between 370 °C and 540 °C corresponding to the crystallization of TiO2 in the anatase phase. The Nyquist plots suggests that the equivalent circuit of the films is an RpCp parallel circuit and shows an increase in resistance Rp with increasing the Ni concentration and a decrease in capacity Cp.

  17. Aging effects of the precursor solutions on the properties of spin coated Ga-doped ZnO thin films

    NASA Astrophysics Data System (ADS)

    Serrao, Felcy Jyothi; Dharmaprakash, S. M.

    2015-06-01

    In this study, gallium doped zinc oxide thin films (GZO) were grown on a glass substrate by a simple sol-gel process and spin coating technique using zinc acetate and gallium nitrate (3at%) as precursors for Zn and Ga ions respectively. The effects of aging time of the precursor solution on the structural and optical properties of the GZO films were investigated. The surface morphology, grain size, film thickness and optical properties of the GZO films were found to depend directly on the sol aging time. XRD studies reveal that the films are polycrystalline with a hexagonal wurtzite structure and show the c-axis grain orientation. Optical transmittance spectra of all the films exhibited transmittance higher than about 82% within the visible wavelength region. A sharp fundamental absorption edge with a slight blue shifting was observed with an increase in sol aging time which can be explained by Burstein-Moss effect. The result indicates that an appropriate aging time of the sol is important for the improvement of the structural and optical properties of GZO thin films derived from sol-gel method.

  18. Aging effects of the precursor solutions on the properties of spin coated Ga-doped ZnO thin films

    SciTech Connect

    Serrao, Felcy Jyothi Dharmaprakash, S. M.

    2015-06-24

    In this study, gallium doped zinc oxide thin films (GZO) were grown on a glass substrate by a simple sol-gel process and spin coating technique using zinc acetate and gallium nitrate (3at%) as precursors for Zn and Ga ions respectively. The effects of aging time of the precursor solution on the structural and optical properties of the GZO films were investigated. The surface morphology, grain size, film thickness and optical properties of the GZO films were found to depend directly on the sol aging time. XRD studies reveal that the films are polycrystalline with a hexagonal wurtzite structure and show the c-axis grain orientation. Optical transmittance spectra of all the films exhibited transmittance higher than about 82% within the visible wavelength region. A sharp fundamental absorption edge with a slight blue shifting was observed with an increase in sol aging time which can be explained by Burstein-Moss effect. The result indicates that an appropriate aging time of the sol is important for the improvement of the structural and optical properties of GZO thin films derived from sol-gel method.

  19. The Effects of Thermal Annealing on ZnO Thin Films Produced by Spin-Coating Method on Quartz Substrates

    NASA Astrophysics Data System (ADS)

    Ertek, Özlem; Okur, İbrahim

    2015-07-01

    In this work, zinc oxide (ZnO) thin films on quartz substrates were fabricated using the spin-coating method. Thermal annealings from to have been performed in increments and for two annealing durations (0.5 h and 8 h). X-ray diffraction (XRD) spectra, scanning electron microscopy micrographs, and UV-Vis absorption spectra of all the samples have been elucidated from mechanical and optical points of view. It has been observed that for all annealing temperatures, the crystal phase has been obtained. After annealings, a new crystal phase related to (willemite) has also been appeared in XRD spectra. This phase remained stable up to annealing together with the ZnO crystal phase. It has been found that the nano/micro rod diameters of the ZnO crystals reach to a maximum at the annealing for both annealing durations. For annealings, ZnO nanorods appeared to be split into two homogeneous nanorods of length of and of width of (350 nm) which was not the case for all other annealing temperatures. After annealings, ZnO nano/micro rods started to disappear and formed homogeneous ZnO thin films.

  20. Highly sensitive detection of organophosphorus pesticides by acetylcholinesterase-coated thin film bulk acoustic resonator mass-loading sensor.

    PubMed

    Chen, Da; Wang, Jingjing; Xu, Yan; Li, Dehua; Zhang, Luyin; Li, Zhaoxin

    2013-03-15

    An acetylcholinesterase-coated thin film bulk acoustic resonator has been developed for the detection of organophosphorus pesticides. The thin film bulk acoustic resonator acts as a robust mass-sensitive transducer for bio-sensing. This device works in thickness shear mode with a resonance at 1.97 GHz. The detection is based on the inhibitory effects of organophosphorus compounds on the enzymatic activity of the acetylcholinesterase immobilized on one of the faces of the acoustic resonator. The enzyme reaction in the substrate solution and the inhibitory effect is observed are real time by measuring the frequency shift. The presence of organophosphorus pesticides can be detected from the diminution of the frequency shift compared with the levels found in their absence. The device exhibits linear responses, good reproducibility, simple operation, portability and a low detection limit of 5.3×10(-11) M for paraoxon. The detection results of organophosphorus pesticide residues in practical samples show that the proposed sensor has the feasibility and sensing accuracy comparable to gas chromatography.

  1. Microstructural and compositional analysis of strontium-doped lead zirconate titanate thin films on gold-coated silicon substrates.

    PubMed

    Sriram, S; Bhaskaran, M; Mitchell, D R G; Short, K T; Holland, A S; Mitchell, A

    2009-02-01

    This article discusses the results of transmission electron microscopy (TEM)-based characterization of strontium-doped lead zirconate titanate (PSZT) thin films. The thin films were deposited by radio frequency magnetron sputtering at 300 degrees C on gold-coated silicon substrates, which used a 15 nm titanium adhesion layer between the 150 nm thick gold film and (100) silicon. The TEM analysis was carried out using a combination of high-resolution imaging, energy filtered imaging, energy dispersive X-ray (EDX) analysis, and hollow cone illumination. At the interface between the PSZT films and gold, an amorphous silicon-rich layer (about 4 nm thick) was observed, with the film composition remaining uniform otherwise. The films were found to be polycrystalline with a columnar structure perpendicular to the substrate. Interdiffusion between the bottom metal layers and silicon was observed and was confirmed using secondary ion mass spectrometry. This occurs due to the temperature of deposition (300 degrees C) being close to the eutectic point of gold and silicon (363 degrees C). The diffused regions in silicon were composed primarily of gold (analyzed by EDX) and were bounded by (111) silicon planes, highlighted by the triangular diffused regions observed in the two-dimensional TEM image.

  2. Polymer-coated compliant receivers for intact laser-induced forward transfer of thin films: experimental results and modelling

    NASA Astrophysics Data System (ADS)

    Feinaeugle, Matthias; Horak, Peter; Sones, Collin L.; Lippert, Thomas; Eason, Rob W.

    2014-09-01

    In this study, we investigate both experimentally and numerically laser-induced forward transfer (LIFT) of thin films to determine the role of a thin polymer layer coating the receiver with the aim of modifying the rate of deceleration and reduction of material stress preventing intact material transfer. A numerical model of the impact phase during LIFT shows that such a layer reduces the modelled stress. The evolution of stress within the transferred deposit and the substrate as a function of the thickness of the polymer layer, the transfer velocity and the elastic properties of the polymer are evaluated. The functionality of the polymer layer is verified experimentally by LIFT printing intact 1- m-thick bismuth telluride films and polymeric light-emitting diode pads onto a layer of 12-m-thick polydimethylsiloxane and 50-nm-thick poly(3,4-ethylenedioxythiophene) blended with poly(styrenesulfonate) (PEDOT:PSS), respectively. Furthermore, it is demonstrated experimentally that the introduction of such a compliant layer improves adhesion between the deposit and its substrate.

  3. Effect of annealing on the structural, morphological and photoluminescence properties of ZnO thin films prepared by spin coating.

    PubMed

    Kumar, Vinod; Kumar, Vijay; Som, S; Yousif, A; Singh, Neetu; Ntwaeaborwa, O M; Kapoor, Avinashi; Swart, H C

    2014-08-15

    Zinc oxide (ZnO) thin films were deposited on silicon substrates by a sol-gel method using the spin coating technique. The ZnO films were annealed at 700°C in an oxygen environment using different annealing times ranging from 1 to 4 h. It was observed that all the annealed films exhibited a hexagonal wurtzite structure. The particle size increased from 65 to 160 nm with the increase in annealing time, while the roughness of the films increased from 2.3 to 10.6 nm with the increase in the annealing time. Si diffusion from the substrate into the ZnO layer occurred during the annealing process. It is likely that the Si and O2 influenced the emission of the ZnO by reducing the amount of Zn defects and the creation of new oxygen related defects during annealing in the O2 atmosphere. The emission intensity was found to be dependent on the reflectance of the thin films.

  4. Luminescence of (Mg,Zn)Al2O4:Tb mixed spinel thin films prepared by spin-coating

    NASA Astrophysics Data System (ADS)

    Kroon, R. E.; Tabaza, W. A. I.; Swart, H. C.

    2015-03-01

    MgAl2O4 and ZnAl2O4 both have the spinel structure and similar lattice constants, but the bandgap of MgAl2O4 is about double that of ZnAl2O4, making it interesting to consider the mixed spinel (MgxZn1-x)Al2O4 as a possible host for luminescent ions. Prior to preparing thin films, the Mg:Zn ratio and Tb concentration were optimized for green luminescence from the 5D4 - 7F5 transition of Tb3+ ions using nanocrystalline samples prepared by combustion synthesis. Thin films with x = 0.75 and 0.5 mol% Tb were spin-coated on Si(100) substrates using a solution of the nitrates of Mg, Zn, Al and Tb in ethanol, with ethylene glycol as complexing agent. Samples about 200 nm thick were obtained by sequentially depositing 10 layers at 3000 rpm for 30 s. Samples were annealed for 1 h in air before measuring their luminescence properties. For the sample annealed at 600 °C, x-ray diffraction showed the thin film had a strong (111) preferential orientation. Atomic force microscopy revealed a root means square roughness of 1 nm and Auger electron spectroscopy depth profiles showed a uniform layer with a sharp interface at the Si substrate. With an increase in annealing temperature up to 1000 °C, the luminescence increased while the surface became slightly rougher and the layer-substrate interface more interdiffused. Annealing the samples at 1200 °C resulted in diffusion of Si through the layer and the formation of an additional phase. While the green Tb emission was slightly reduced, blue emission from the 5D3 level of Tb3+ was greatly enhanced in these samples.

  5. Novel intercore-cladding lithium niobate thin film coated MOEMS fiber sensor/modulator

    NASA Technical Reports Server (NTRS)

    Jamlson, Tracee L.; Konreich, Phillip; Yu, Chung

    2005-01-01

    A MOEMS fiber modulator/sensor is fabricated by depositing a lithium niobate sol-gel thin film between the core and cladding of a fiber preform. The preform is then drawn into 125-micron fibers. Such a MOEMS modulator design is expected to enhance existing lithium niobate undersea acousto-optic sound wave detectors. In our proposed version, the lithium niobate thin film alters the ordinary silica core/cladding boundary conditions such that, when a stress or strain is applied to the fiber, the core light confinement factor changes, leading to modulation of fiber light transmission. Test results of the lithium niobate embedded fiber with a 1550-nm, 4-mW laser source revealed a reduction in light transmission with applied tension. As a comparison, using the same laser source, an ordinary silica core/cladding fiber did not exhibit any reduction in transmitted light when the same strain was applied. Further experimental work and theoretical analysis is ongoing.

  6. A graphene-oxide-based thin coating on the separator: an efficient barrier towards high-stable lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Yunbo; Miao, Lixiao; Ning, Jing; Xiao, Zhichang; Hao, Long; Wang, Bin; Zhi, Linjie

    2015-06-01

    The electrochemical performance of lithium-sulfur (Li-S) batteries can be significantly improved by simply coating a thin barrier layer on the separator. The spray-coating of a mixture of graphene oxides (GO) and oxidized carbon nanotubes (o-CNT) can achieve a barrier coating of only 0.3 mg cm-2, which is much less than conventional interlayers and has no negative impact on the energy density but significantly enhances the electrochemical performances of the whole battery device. Due to the binding forces induced by functional groups on GO and the interconnected nanoscale channels provided by o-CNT, the thus fabricated Li-S batteries show dramatically improved specific discharge capacities of up to 750 mAh g-1 at 1 C even after 100 cycles, more than twice those of batteries without barrier coatings.

  7. Study of the picosecond laser damage in HfO2/SiO2-based thin-film coatings in vacuum

    NASA Astrophysics Data System (ADS)

    Kozlov, A. A.; Papernov, S.; Oliver, J. B.; Rigatti, A.; Taylor, B.; Charles, B.; Smith, C.

    2016-12-01

    The laser damage thresholds of various HfO2/SiO2-based thin film coatings, including multilayer dielectric (MLD) gratings and high reflectors of different designs, prepared by E-beam and Plasma Ion Assisted Deposition (PIAD) methods, were investigated in vacuum, dry nitrogen, and after air-vacuum cycling. Single and multiple-pulse damage thresholds and their pulse-length scaling in the range of 0.6 to 100 ps were measured using a vacuum damage test station operated at 1053nm. The E-beam deposited high reflectors showed higher damage thresholds with square-root pulse-length scaling, as compared to PIAD coatings, which typically show slower power scaling. The former coatings appeared to be not affected by air/vacuum cycling, contrary to PIAD mirrors and MLD gratings. The relation between 1-on-1 and N-on-1 damage thresholds was found dependent on coating design and deposition methods.

  8. Optimized 2D array of thin silicon pillars for efficient antireflective coatings in the visible spectrum

    PubMed Central

    Proust, Julien; Fehrembach, Anne-Laure; Bedu, Frédéric; Ozerov, Igor; Bonod, Nicolas

    2016-01-01

    Light reflection occuring at the surface of silicon wafers is drastically diminished by etching square pillars of height 110 nm and width 140 nm separated by a 100 nm gap distance in a square lattice. The design of the nanostructure is optimized to widen the spectral tolerance of the antireflective coatings over the visible spectrum for both fundamental polarizations. Angle and polarized resolved optical measurements report a light reflection remaining under 5% when averaged in the visible spectrum for both polarizations in a wide angular range. Light reflection remains almost insensitive to the light polarization even in oblique incidence. PMID:27109643

  9. High-performance FeSe0.5Te0.5 thin films fabricated on less-well-textured flexible coated conductor templates

    NASA Astrophysics Data System (ADS)

    Xu, Zhongtang; Yuan, Pusheng; Ma, Yanwei; Cai, Chuanbing

    2017-03-01

    We report on the transport properties of FeSe0.5Te0.5 (FST) thin films fabricated on less-well-textured flexible coated conductor templates with LaMnO3 (LMO) as buffer layers using pulsed laser deposition. The LMO buffer layers exhibit large in-plane misalignment of ˜7.72°, which is unfavorable for cuprate-coated conductors due to the high grain boundaries. The FST thin films show a superconducting transition temperature of 16.8 K, higher than that of bulk materials due to the compressive strain between LMO and FST. Atomic force microscopy observations reveal that island-like features appear at the surfaces of both LMO and FST, confirming the island growth mode. A self-field transport critical-current density of up to 0.43 MA cm-2 at 4.2 K has been observed in FST thin films, which is much higher than that in powder-in-tube processed FST tapes. The films are capable of carrying current densities of over 105 A cm-2 in the whole applied magnetic field up to 9 T, showing great potential for high-field applications. The results indicate that, for FST, highly textured metal tapes are not needed to produce coated conductors with high performance, which is of great advantage over cuprate-coated conductors.

  10. Synthesis of Superhard Thin Films and Coatings Based on Light Elements

    DTIC Science & Technology

    2007-11-02

    V.M. Torres, B.J. Wilkens, D.J. Smith, J. Kouvetakis and I.S.T. Tsong, “Elastic properties of nanocrystalline zirconium -silicon-boron thin films ”, J...III nitrides on silicon substrates via a reflective lattice-matched zirconium diboride buffer layer”, Appl. Phys. Lett. 82, 2398-2400 (2003). REPORT...nitrides on silicon substrates via a reflective lattice-matched zirconium diboride buffer layer”, J. Kouvetakis, I.S.T. Tsong, J. Tolle and R

  11. CdSe:In-In{sub 2}O{sub 3} coatings with n-type conductivity produced by air annealing of CdSe-In thin films

    SciTech Connect

    Garcia, V.M.; George, P.J.; Nair, M.T.S.; Nair, P.K.

    1996-09-01

    Conversion of chemically deposited intrinsic CdSe thin films to n-type coatings by a postdeposition process is described. A Cd:Se-In thin film consisting of a CdSe thin film {approximately}0.15 {micro}m thick and a thermally evaporated indium film {approximately} 0.02 {micro}m thick was air annealed at 325 C for 1 h. The resulting thin film coating of CdSe:In (0.15 {micro}m)-In{sub 2}O{sub 3} (0.03 {micro}m) exhibits a sheet resistance of 790 {Omega}/{open_square} and an n-type conductivity of {approximately} 400 {Omega}{sup {minus}1} cm{sup {minus}1} for the In{sub 2}O{sub 3} top layer. Etching of the film with 1 M HCl for 6 h removes the superficial In{sub 2}O{sub 3} from the coating, and the underlying CdSe with indium doping shows a sheet resistance of 15 k{Omega}/{open_square} which corresponds to electrical conductivity (n-type) of {approximately}0.4 {Omega}{sup {minus}1} cm{sup {minus}1}. The composition of the film and its variation along the depth are established through analyses of X-ray diffraction pattern and x-ray fluorescence spectra as well as the photocurrent response of the annealed films recorded before and after chemical etching.

  12. Near infrared ray annealing effects on the properties of Al-doped ZnO thin films prepared by spin-coating method.

    PubMed

    Jun, Min-Chul; Park, Sang-Uk; Chae, Moon-Soon; Shin, Dong-Jin; Ha, Jae-Geun; Koo, Sang-Mo; Lee, Kyung-Ju; Moon, Byung-Moo; Song, Chi-Young; Koh, Jung-Hyuk

    2013-09-01

    In this research, we will present Al doped ZnO thin films for transparent conducting oxide applications. Aluminum doped zinc oxide (AZO) thin films have been deposited on the glass substrates by sol-gel spin-coating method using zinc acetate dehydrate (Zn(CH3COO)2 2H2O) and aluminum chloride hexahydrate (AlCl3 x 6H2O) as cation sources. In this study, we investigated the effects of near infrared ray (NIR) annealing on the structural, optical and electrical characteristics of the AZO thin films. The experimental results showed that AZO thin films have a hexagonal wurtzite crystal structure and had a good transmittance higher than 85% within the visible wavelength region. It was also found that the additional energy of NIR helps to improve the electrical properties of Al doped ZnO transparent conducting oxides.

  13. Formation of silicon nanodots via ion beam sputtering of ultrathin gold thin film coatings on Si

    PubMed Central

    2011-01-01

    Ion beam sputtering of ultrathin film Au coatings used as a physical catalyst for self-organization of Si nanostructures has been achieved by tuning the incident particle energy. This approach holds promise as a scalable nanomanufacturing parallel processing alternative to candidate nanolithography techniques. Structures of 11- to 14-nm Si nanodots are formed with normal incidence low-energy Ar ions of 200 eV and fluences above 2 × 1017 cm-2. In situ surface characterization during ion irradiation elucidates early stage ion mixing migration mechanism for nanodot self-organization. In particular, the evolution from gold film islands to the formation of ion-induced metastable gold silicide followed by pure Si nanodots formed with no need for impurity seeding. PMID:21711934

  14. Preparation of platinum- and silver-incorporated TiO2 coatings in thin-film photoreactor for the photocatalytic decomposition of o-cresol.

    PubMed

    Kuo, Yu-Lin; Su, Te-Li; Chuang, Kai-Jen; Chen, Hua-Wei; Kung, Fu-Chen

    2011-12-01

    Platinum-incorporated TiO2 (Pt-TiO2) and silver-incorporated TiO2 (Ag-TiO2) coatings on sapphire tubes of a thin-film photoreactor were prepared using a photoreduction process. Results of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) revealed that the Ag-TiO2 coatings consisted of a mixture of Ag2O, Ag and TiO2 particles, owing to the partial oxidization of silver particles on the TiO2 coatings, while the Pt-TiO2 coating contained a mixture of Pt and TiO2 particles. Diffuse reflectance UV-Vis spectra (DRS) showed that metal particles (Ag or Pt) incorporated into the TiO2 coatings promoted optical absorption in the visible region and made it possible for the coatings to be excited by visible light. Photoluminescence (PL) spectra showed that the PL intensity of the Pt-TiO2 coating was lower than that of the Ag-TiO2 and TiO2 coatings, indicating that the Pt-TiO2 coating had a higher efficiency of charge carrier trapping, immigration and transfer, which subsequently promoted the pseudo-first-order rate constants after the UV/TiO2 process. The Pt-TiO2 coatings for the photocatalytic decomposition of o-cresol under UV light irradiation corresponded to a higher pseudo-first-order rate constant (k) of 0.02 min(-1) when compared with the photocatalytic decomposition rates of pure TiO2 coatings (k = 0.0062 min(-1)) and Ag-TiO2 coatings (k = 0.01 min(-1)). The experimental results also indicated that the photodegradation rate of the Pt-TiO2 coating under visible light irradiation was significantly higher than the photodegradation rates of the Ag-TiO2 and pure TiO2 coatings.

  15. Comparison of Y2O3:Bi3+ phosphor thin films fabricated by the spin coating and radio frequency magnetron techniques

    NASA Astrophysics Data System (ADS)

    Jafer, R. M.; Yousif, A.; Kumar, Vinod; Pathak, Trilok Kumar; Purohit, L. P.; Swart, H. C.; Coetsee, E.

    2016-09-01

    The reactive radio-frequency (RF) magnetron sputtering and spin coating fabrication techniques were used to fabricate Y2-xO3:Bix=0.5% phosphor thin films. The two techniques were analysed and compared as part of investigations being done on the application of down-conversion materials for a Si solar cell. The morphology, structural and optical properties of these thin films were investigated. The X-ray diffraction results of the thin films fabricated by both techniques showed cubic structures with different space groups. The optical properties showed different results because the Bi3+ ion is very sensitive towards its environment. The luminescence results for the thin film fabricated by the spin coating technique is very similar to the luminescence observed in the powder form. It showed three obvious emission bands in the blue and green regions centered at about 360, 410 and 495 nm. These emissions were related to the 3P1-1S0 transition of the Bi3+ ion situated in the two different sites of the Y2O3 matrix with I a-3(206) space group. Whereas the thin film fabricated by the radio frequency magnetron technique showed a broad single emission band in the blue region centered at about 416 nm. This was assigned to the 3P1-1S0 transition of the Bi3+ ion situated in one of the Y2O3 matrix's sites with a Fm-3 (225) space group. The spin coating fabrication technique is suggested to be the best technique to fabricate the Y2O3:Bi3+ phosphor thin films.

  16. Characteristic of skin formation using zircon- and graphite-coated mold in thin wall ductile iron fabrication

    NASA Astrophysics Data System (ADS)

    Dhaneswara, Donanta; Suharno, Bambang; Nugroho, Janu Ageng; Ariobimo, Rianti Dewi S.; Sofyan, Nofrijon

    2017-03-01

    One of the problems in thin wall ductile iron (TWDI) fabrication is skin formation during the casting. The presence of this skin will decrease strength and strain of the TWDI. One of the ways to control this skin formation is to change the cooling rate during the process through a mold coating. In testing the effectiveness of skin prevention, the following variables were used for the mold coating i.e. (i) graphite: (ii) zirconium; and (iii) double layer of graphite-zirconium. After the process, the plates were characterized by non-etching, etching, tensile test, and SEM observation. The results showed that the average skin formation using graphite: 65 µm; zirconium: 13.04 µm; and double layer of graphite-zirconium: 33.25 µm. It seems that zirconium has the most effect on the skin prevention due to sulfur binding and magnesium locked, which then prevented rapid cooling resulting in less skin formation. The results also showed the number of nodules obtained in specimen with graphite: 703 nodules/mm2 with average diameter of 12.57 µm, zirconium: 798 nodules/mm2 with average diameter of 12.15 µm, and double layer of graphite-zirconium: 697 nodules/mm2 with average diameter of 11.9 µm and nodularity percentage of 82.58%, 84.53%, and 84.22%, respectively. Tensile test showed that the strength of the specimen with graphite is 301.1 MPa, with zirconium is 388.8 MPa, and with double layer of graphite-zirconium is 304 MPa. In overall, zirconium give the best performance on the skin formation prevention in TWDI fabrication.

  17. Vertical phase separation and liquid-liquid dewetting of thin PS/PCL blend films during spin coating.

    PubMed

    Ma, Meng; He, Zhoukun; Yang, Jinghui; Wang, Qi; Chen, Feng; Wang, Ke; Zhang, Qin; Deng, Hua; Fu, Qiang

    2011-02-01

    Thin films of an amorphous polymer, polystyrene (PS), and a crystalline polymer, poly(ε-caprolactone) (PCL), blend were prepared by spin coating a toluene solution. Surface chemical compositions of the blend films were measured by X-ray photoelectron spectroscopy (XPS), and the surface and interface topographical changes were followed by atomic force microscopy (AFM). By changing the PS concentration and keeping the PCL concentration of the solution at 1 wt %, a great variety of morphologies were constructed. The results show that the morphology of the blend films can be divided into three regions with increasing PS concentration. In region I, PS island domains are embedded in PCL crystals when the PS concentration is lower than 0.3 wt % and the size of the PS island increases with increasing PS concentration. In region II, holes with different sizes surrounded by a low rim are obtained when the concentration of PS is between 0.35 and 0.5 wt %. After selectively washing the PS domains, we studied the interface morphology of PS/PCL and found that the upper PS-rich layer extended into the bottom PCL layer, forming a trench surrounding the holes. In region III, an enriched two-layer structure with the PS-rich layer on top of the blend films and the PCL-rich crystal layer underneath is obtained when the concentration of PS is higher than 0.5 wt %. Last, the formation mechanism of the different surface and interface morphologies is further discussed in terms of the vertical phase separation to a layered structure, followed by liquid-liquid dewetting and crystallization processes during spin coating.

  18. A Novel Inter Core-Cladding Lithium Niobate Thin Film Coated Fiber Modulator/Sensor

    NASA Technical Reports Server (NTRS)

    Jamison, Tracee L.; Komriech, Phillip; Yu, Chung

    2004-01-01

    A fiber modulator/sensor has been fabricated by depositing a lithium niobate sol-gel thin film between the core and cladding of a fiber preform. The preform is then drawn into 125 micron fiber. The proposed design of lithium niobate cylinder fibers can enhance the existing methodology for detecting sound waves under water utilizing the acoustooptic properties of lithium niobate. Upon application of a stress or strain, light propagating inside the core, according to the principle of total internal reflection, escapes, into the cladding because of the photoelastic boundary layer of lithium niobate. Test results of the lithium niobate fiber reveal a reduction in the 1550 nm, 4mW source with applied tension. The source power from an ordinary quartz fiber under the same stress condition remained invariant to applied tension.

  19. Niobium thin film coating on a 500-MHz copper cavity by plasma deposition

    SciTech Connect

    Haipeng Wang; Genfa Wu; H. Phillips; Robert Rimmer; Anne-Marie Valente; Andy Wu

    2005-05-16

    A system using an Electron Cyclotron Resonance (ECR) plasma source for the deposition of a thin niobium film inside a copper cavity for superconducting accelerator applications has been designed and is being constructed. The system uses a 500-MHz copper cavity as both substrate and vacuum chamber. The ECR plasma will be created to produce direct niobium ion deposition. The central cylindrical grid is DC biased to control the deposition energy. This paper describes the design of several subcomponents including the vacuum chamber, RF supply, biasing grid and magnet coils. Operational parameters are compared between an operating sample deposition system and this system. Engineering work progress toward the first plasma creation will be reported here.

  20. Conductive conformal thin film coatings for textured PV: ALD versus sputtering

    NASA Astrophysics Data System (ADS)

    Dameron, Arrelaine; Christensen, Steven; Galante, Marie; Berry, Joseph; Gillaspie, Dane; Perkins, John; Ginley, David; Gennett, Thomas

    2011-09-01

    Next-generation photovoltaic structures require well-established deposition routes to conformal and conducting materials with defined chemical, physical and electronic composition. This work reports on the preliminary findings associated with conformal metal oxides on structured substrates including: 1) Discovery of sputtering process conditions that can be made semi-conformal when combined with in-situ techniques such as ion-beam milling for honing surface structures; 2) Development of relevant ALD chemistries that are materials-properties competitive with sputtered materials; 3) Evaluation of chemically-functionalized surface structures that maximize surface area but are structurally tailored for efficient gas flow and to minimize line-of-sight shadowing. The initial experiments have centered on combinations of amorphous and crystalline indium oxide, zinc oxide, aluminum zinc oxide, indium tin oxide, fluorinated tin oxide and indium zinc oxide. This presentation will describe these initial experiments and elucidate key physiochemical nature of the deposited thin films.

  1. Electrical Properties Analysis of Copper doped CdTe/CdS Deposited Thin Films on ITO Coated Glass Substrates

    NASA Astrophysics Data System (ADS)

    Lesinski, Darren; Flaherty, James; Sahiner, M. Alper

    CdTe proves to be a viable source for renewable energy in the form of photovoltaic conversion. While CdTe/CdS naturally provide interesting results adding dopants to the cell can yield higher conversion efficiencies. Copper, famous for its electrical properties, can be used as a dopant in the CdTe layer. In conjunction with its dopant characteristics Copper also improves cell performance by acting as a low resistant and high current back contact. All thin films were synthesized using pulsed laser deposition onto ITO coated glass substrates. The CdS layer across all cells has an approximate thickness of 1500 Angstroms. The following CdTe layer has an approximate thickness of 5500 Angstroms. This created the base cell that was then doped. Cu, typically deposited using sublimation or vapor deposition, was done by PLD as well. Two of the three base cells were treated with Cu using the same deposition parameters. The third cell also received a CdCl treatment on top of the Cu layer to understand the effect when the oxygen layer is deferred. Ellipsometer measurements were used to confirm layer thickness. XRD analysis was used to confirm the presence of Cu and the crystal structure of the thin films. A Hall Effect Measurement system was used to measure active charge carrier concentration introduced by dopant. Also, a Keithley sourcemeter was utilized to determine photovoltaic properties. Notable results discussed will be the effects of Copper dopant on the electrical properties of CdS/CdTe based solar cells.

  2. Thin-film optical notch filter spectacle coatings for the treatment of migraine and photophobia.

    PubMed

    Hoggan, Ryan N; Subhash, Amith; Blair, Steve; Digre, Kathleen B; Baggaley, Susan K; Gordon, Jamison; Brennan, K C; Warner, Judith E A; Crum, Alison V; Katz, Bradley J

    2016-06-01

    Previous evidence suggests optical treatments hold promise for treating migraine and photophobia. We designed an optical notch filter, centered at 480nm to reduce direct stimulation of intrinsically photosensitive retinal ganglion cells. We used thin-film technology to integrate the filter into spectacle lenses. Our objective was to determine if an optical notch filter, designed to attenuate activity of intrinsically photosensitive retinal ganglion cells, could reduce headache impact in chronic migraine subjects. For this randomized, double-masked study, our primary endpoint was the Headache Impact Test (HIT-6; GlaxoSmithKline, Brentford, Middlesex, UK). We developed two filters: the therapeutic filter blocked visible light at 480nm; a 620nm filter was designed as a sham. Participants were asked to wear lenses with one of the filters for 2weeks; after 2weeks when no lenses were worn, they wore lenses with the other filter for 2weeks. Of 48 subjects, 37 completed the study. Wearing either the 480 or 620nm lenses resulted in clinically and statistically significant HIT-6 reductions. However, there was no significant difference when comparing overall effect of the 480 and 620nm lenses. Although the 620nm filter was designed as a sham intervention, research published following the trial indicated that melanopsin, the photopigment in intrinsically photosensitive retinal ganglion cells, is bi-stable. This molecular property may explain the unexpected efficacy of the 620nm filter. These preliminary findings indicate that lenses outfitted with a thin-film optical notch filter may be useful in treating chronic migraine.

  3. Remote quantitative temperature and thickness measurements of plasma-deposited titanium nitride thin coatings on steel using a laser interferometric thermoreflectance optical thermometer

    SciTech Connect

    Liu Yue; Mandelis, Andreas; Choy, Mervyn; Wang, Chinhua; Segal, Lee

    2005-08-15

    An optical thermometer based on the principle of laser thermoreflectance has been introduced to monitor the surface temperature of thin coatings on steel parts undergoing an industrial titanium nitride (TiN) alloy deposition process. To study the feasibility of the optical thermometer, various thermo-optical parameters of TiN affected by the deposition process have been investigated; namely, the reflectance-temperature relation, the thermoreflectance coefficient, and the coating thickness dependence of thermoreflectance and of total reflectance. A theory of interferometric thermoreflectance has been introduced to model the total reflectance variations during the coating process. An inverse reflectance-temperature relation for the TiN-D2 steel substrate system has been found and a first-order Taylor series expansion used to model thermoreflectance has been shown to yield a thermoreflectance coefficient which is independent of temperature. Both results are in quantitative agreement with the Drude-Zener theory of conductors and semi-conductors. An empirical formula has been derived to effectively model the experimental thermoreflectance coefficient dependence of the TiN-D2 steel system on TiN coating thickness, in qualitative agreement with scattering mechanisms of the Boltzmann transport theory in conductors and semiconductors. The good agreement of theoretical interferometric thermoreflectance simulations with in situ measurements during a specific industrial TiN sputter-coating growth process and the independence of the thermoreflectance and thin-coating-thickness reflectance coefficients from temperature show the potential of using this nonintrusive noncontacting technique as an optical thermometer to determine surface temperatures of physically inaccessible samples undergoing industrial coating deposition processes.

  4. CuInSe₂ thin-film solar cells with 7.72 % efficiency prepared via direct coating of a metal salts/alcohol-based precursor solution.

    PubMed

    Ahn, Sejin; Son, Tae Hwa; Cho, Ara; Gwak, Jihye; Yun, Jae Ho; Shin, Keeshik; Ahn, Seoung Kyu; Park, Sang Hyun; Yoon, Kyunghoon

    2012-09-01

    A simple direct solution coating process for forming CuInSe₂ (CIS) thin films was described, employing a low-cost and environmentally friendly precursor solution. The precursor solution was prepared by mixing metal acetates, ethanol, and ethanolamine. The facile formation of a precursor solution without the need to prefabricate nanoparticles enables a rapid and easy processing, and the high stability of the solution in air further ensures the precursor preparation and the film deposition in ambient conditions without a glove box. The thin film solar cell fabricated with the absorber film prepared by this route showed an initial conversion efficiency of as high as 7.72 %.

  5. Study on polarization characteristics of BiFeO3 thin films prepared by sol-gel spin-coating technology

    NASA Astrophysics Data System (ADS)

    Jia, Ze; Wu, Xiao; Zhang, Mingming; Xu, Jianlong; Zhang, Naiwen; Liou, Juin J.

    2015-07-01

    The ferroelectric polarization properties of bismuth ferrite (BFO) thin films deposited on Pt(111)/TiO2/SiO2/Si(100) substrates by sol-gel spin-coating technology affected by the processes and dopants have been studied and analyzed tentatively. The results indicate BFO thin film should be introduced to a rapid thermal annealing (RTA) process at N2 atmosphere. The enhanced ferroelectric polarization properties were observed in Mn and La doped BFO thin films, because ion substitution may improve the inherent volatility of Bi atoms, valence fluctuation of Fe ions and magnetic spin structures, reducing the formation of oxygen vacancies. The increased remnant polarization observed in the BFO thin film with a lead zirconate titanate (PZT) seeding layer has also been analyzed as the probable results of small changes of lattice parameters caused by constraint stress, reduced defects and decreased leakage current density, which are contributed by the PZT seeding layer possibly. Moreover, the remnant polarization approximately 79 μC/cm2 is observed in (Bi0.95La0.05)FeO3 (BLFO) thin film with a PZT seeding layer, which is twice and treble the values of BFO thin films with and without a PZT seeding layer, indicating PZT seeding layer is much more effective for BLFO thin film which has a substitution at A site.

  6. Biphasic Electrical Field Stimulation Aids in Tissue Engineering of Multicell-Type Cardiac Organoids

    PubMed Central

    Chiu, Loraine L.Y.; Iyer, Rohin K.; King, John-Paul

    2011-01-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence. PMID:18783322

  7. Biphasic electrical field stimulation aids in tissue engineering of multicell-type cardiac organoids.

    PubMed

    Chiu, Loraine L Y; Iyer, Rohin K; King, John-Paul; Radisic, Milica

    2011-06-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence.

  8. Hydroxyapatite/polylactide biphasic combination scaffold loaded with dexamethasone for bone regeneration.

    PubMed

    Son, Jun-Sik; Kim, Su-Gwan; Oh, Ji-Su; Appleford, Mark; Oh, Sunho; Ong, Joo L; Lee, Kyu-Bok

    2011-12-15

    This study presents a novel design of a ceramic/polymer biphasic combination scaffold that mimics natural bone structures and is used as a bone graft substitute. To mimic the natural bone structures, the outside cortical-like shells were composed of porous hydroxyapatite (HA) with a hollow interior using a polymeric template-coating technique; the inner trabecular-like core consisted of porous poly(D,L-lactic acid) (PLA) that was loaded with dexamethasone (DEX) and was directly produced using a particle leaching/gas forming technique to create the inner diameter of the HA scaffold. It was observed that the HA and PLA parts of the fabricated HA/PLA biphasic scaffold contained open and interconnected pore structures, and the boundary between both parts was tightly connected without any gaps. It was found that the structure of the combination scaffold was analogous to that of natural bone based on micro-computed tomography analysis. Additionally, the dense, uniform apatite layer was formed on the surface of the HA/PLA biphasic scaffold through a biomimetic process, and DEX was successfully released from the PLA of the biphasic scaffold over a 1-month period. This release caused human embryonic palatal mesenchyme cells to proliferate, differentiate, produce ECM, and form tissue in vitro. Therefore, it was concluded that this functionally graded scaffold is similar to natural bone and represents a potential bone-substitute material.

  9. Thin metal organic frameworks coatings by cathodic electrodeposition for solid-phase microextraction and analysis of trace exogenous estrogens in milk.

    PubMed

    Lan, Hangzhen; Pan, Daodong; Sun, Yangying; Guo, Yuxing; Wu, Zhen

    2016-09-21

    Cathodic electrodeposition (CED) has received great attention in metal-organic frameworks (MOFs) synthesis due to its distinguished properties including simplicity, controllability, mild synthesis conditions, and product continuously. Here, we report the fabrication of thin (Et3NH)2Zn3(BDC)4 (E-MOF-5) film coated solid phase microextraction (SPME) fiber by a one-step in situ cathodic electrodeposition strategy. Several etched stainless steel fibers were placed in parallel in order to achieve simultaneously electrochemical polymerization. The influence of different polymerization parameters Et3NHCl concentration and polymerization time were evaluated. The proposed method requires only 20 min for the preparation of E-MOF-5 coating. The optimum coating showed excellent thermal stability and mechanical durability with a long lifetime of more than 120 repetitions SPME operations, and also exhibited higher extraction selectivity and capacity to four estrogens than commonly-used commercial PDMS coating. The limits of detection for the estrogens were 0.17-0.56 ng mL(-1). Fiber-to-fiber reproducibility (n = 8) was in the respective ranges of 3.5%-6.1% relative standard deviation (RSD) for four estrogens for triplicate measurements at 200 ng mL(-1). Finally, the (E-MOF-5) coated fiber was evaluated for ethinylestradiol (EE2), bisphenol A (BPA), diethylstilbestrol (DES), and hexestrol (HEX) extraction in the spiked milk samples. The extraction performance of this new coating was satisfied enough for repeatable use without obvious decline.

  10. a-SiCxNy:H thin films for applications in solar cells as passivation and antireflective coatings

    NASA Astrophysics Data System (ADS)

    Swatowska, Barbara; Kluska, Stanisława; Lewińska, Gabriela; Golańska, Julia; Stapiński, Tomasz

    2016-12-01

    Amorphous a-SiCxNy:H thin films may be an alternative to a-Si:N:H coatings which are commonly used in silicon solar cells. This material was obtained by PECVD (13.56 MHz) method. The reaction gases used: silane, methane, nitrogen and ammonia. The structure of the layers were investigated by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). IR absorption spectra of a-SiCxNy:H layers confirmed the presence of various hydrogen bonds - it is important for passivation of Si structural defects. The ellipsometric measurements were implemented to determine the thickness of layers d, refractive index n, extinction coefficient k and energy gap Eg. The values of the energy gap of a-SiCxNy:H layers are in the range from 1.89 to 4.34 eV. The correlation between energy gap of materials and refractive index was found. Generally the introduction of N and/or C into the amorphous silicon network rapidly increases the Eg values.

  11. High-κ TiO2 thin film prepared by sol-gel spin-coating method

    NASA Astrophysics Data System (ADS)

    Kumar, Arvind; Mondal, Sandip; Rao, K. S. R. Koteswara

    2015-06-01

    High-k TiO2 thin film on p-type silicon substrate was fabricated by a combined sol-gel and spin coating method. Thus deposited titania film had anatase phase with a small grain size of 16 nm and surface roughness of ≅ 0.6 nm. The oxide capacitance (Cox), flat band capacitance (CFB), flat band voltage (VFB), oxide trapped charge (Qot), calculated from the high frequency (1 MHz) C-V curve were 0.47 nF, 0.16 nF, - 0.91 V, 4.7x10-12 C, respectively. As compared to the previous reports, a high dielectric constant of 94 at 1 MHz frequency was observed in the devices investigated here and an equivalent oxide thickness (EOT) was 4.1 nm. Dispersion in accumulation capacitance shows a linear relationship with AC frequencies. Leakage current density was found in acceptable limits (2.1e-5 A/cm2 for -1 V and 5.7e-7 A/cm2 for +1 V) for CMOS applications.

  12. Characteristic study on volatile organic compounds optical fiber sensor with zeolite thin film-coated spherical end

    NASA Astrophysics Data System (ADS)

    Wu, Binqing; Zhao, Chunliu; Kang, Juan; Wang, Dongning

    2017-03-01

    In this paper, characteristic of volatile organic compounds (VOCs) optical fiber sensor with zeolite thin film-coated spherical end were investigated detailedly. The zeolite film and spherical end constituted an arc-shaped inline Fabry-Perot (F-P) cavity, and VOCs were measured by monitoring the wavelength shift of F-P interference which induced by the VOCs molecule adsorption of the zeolite film. The responses of the optical fiber sensor for monitoring isopropanol and formaldehyde were observed and especially observing the response of the optical fiber sensor in the mixed VOCs state. Experimental results show that the sensitivities of the optical fiber sensor for monitoring isopropanol and formaldehyde are 281.9 pm/ppm and 4.99 pm/ppm, respectively. The optical fiber sensor is more suitable for isopropanol measurement than formaldehyde. In the mixed VOCs state, the characteristic of the optical fiber sensor for isopropanol measurement is slightly changed when the air chamber is mixed with low concentration of formaldehyde, but the optical fiber sensor is still effective for isopropanol measurement.

  13. Micro-structuring of CIGS thin-film coated on Mo back contact by ultrafast laser 'rail-roading' patterning.

    PubMed

    Jeoung, Sae Chae; Lee, Heung-Soon; Yahng, Ji Sang; Lee, Hyun Kyu; Moon, Heh Young; Kim, Kyoun Joon; Lee, Dong Geun; Park, Duck Hoon; Yu, Young Sam; Ji, Suk-Jae

    2011-08-29

    We report selective patterning process, laser 'rail-roading' scribing method, of which operating principle is based on transient force balance between the material properties including cohesion and adhesion forces subjected to underlying substrate and laser-induced shock compression and shear forces. By using dual fs-laser beam lines with an interval larger than laser spot size, we provide a proof of the concept by patterning the photovoltaic modules based on CIGS (Cu(In,Ga)Se2) coated on Mo electrode. With varying the interval between the two laser beam tracks, we can provide intact Mo back contact surface without any residues in a manner of more facile, high-speed and high scribing efficiency. We have interpreted the effect of the ambient gases and grooving width on the scribing performance in terms of the cohesion forces between the grains of CIGS thin films as well as adhesion force between underlying Mo layer and CIGS, which are mainly governed by local laser ablation and peening process followed by laser-induced shock compression, respectively.

  14. Conditions for the Formation of P3 HT Organogels During Spin-Coating: Tuning Electrical Properties in Thin Films

    NASA Astrophysics Data System (ADS)

    Lee, Cameron S.; Yen, Wen; Holt, Adam; Sangoro, Joshua; Sokolov, Alexei; Dadmun, Mark D.

    2015-03-01

    Poly(3-hexyl thiophene) (P3HT) is widely studied as a model conjugated polymer in many electrical and photovoltaic applications, and has become the benchmark polymer when studying the physics of these devices. The assembly and growth of P3HT as organogels offers a structure that can bridge the electrodes, providing more efficient transport throughout the active layer. In this work, we identify and discuss a novel set of conditions for P3HT organogel network formation by controlling the spin-coating process from various solvents. The onset of organogel formation was monitored by in situ static light scattering, which measured both the thinning rate and off-specular scattering during film formation. Optical microscopy and thermal annealing experiments provide ex situ confirmation of organogel fabrication. The role of solution characteristics, including solvent boiling point, P3HT solubility, and initial P3HT solution concentration are examined to correlate these parameters to the rate of film formation, organogel-onset concentration, and overall network size. The properties of the film and their correlation to the fabrication parameters were also analyzed within the context of the hole mobility and density-of-states of the organogel, as measured from impedance spectroscopy.

  15. Fabrication of a thin-layer solid optical tissue phantom by a spin-coating method: pilot study

    NASA Astrophysics Data System (ADS)

    Bae, Yunjin; Son, Taeyoon; Park, Jihoon; Jung, Byungjo

    2013-02-01

    Solid optical tissue phantoms (OTPs) have been widely used for many purposes. This study introduces a spin-coating method (SCM) to fabricate a thin-layer solid OTP (TSOTP) with epidermal thickness. TSOTPs are fabricated by controlling the spin speed (250 to 2500 rpm), absorber concentration (0.2% to 1.0%), and the number of layers. The results show that the thicknesses of the TSOTPs are homogeneous in the region of interest. The one-layer TSOTP achieves maximum and minimum thicknesses of 65±0.28 μm (250 rpm) and 5.1±0.17 μm (2500 rpm), respectively, decreasing exponentially as a function of the spin speed. The thicknesses of the multilayer TSOTPs increases as a function of the number of layers and are correlated strongly with the spin speed (R2≥0.95). The concentration of the OTP mixture does not directly affect the thickness of the TSOTP; however, the absorption coefficients exponentially increase as a function of absorber concentration (R2≥0.98). These results suggest that the SCM can be used to fabricate homogeneous TSOTPs with various thicknesses by controlling the spin speed and number of layers. Finally, a double-layer OTP that combines epidermal TSOTP and dermal OTP is manufactured as a preliminary study to investigate the practical feasibility of TSOTPs.

  16. Growth of CdS thin films on indium coated glass substrates via chemical bath deposition and subsequent air annealing

    NASA Astrophysics Data System (ADS)

    Ghosh, Biswajit; Kumar, Kamlesh; Singh, Balwant Kr; Banerjee, Pushan; Das, Subrata

    2014-11-01

    In the present work attempts were made to synthesize indium doped CdS films by fabricating In/CdS bilayers using CBD-CdS on vacuum evaporated In thin films and subsequent air annealing. 135 nm CdS films were grown onto 20 nm and 35 nm indium coated glass substrate employing chemical bath deposition technique. The In/CdS bilayers thus formed were subjected to heat treatment at the temperatures between 200 and 400 °C for 4 min in the muffle furnace to facilitate indium to diffuse into the CdS films. XRD pattern ascertained no noticeable shift in lattice constant implying grain boundary metal segregation, while secondary ion mass spectrometry indicated the diffusion profile of indium into CdS matrices. Mass spectrometry results showed that substantial diffusion of indium had been taken place within CdS at 400 °C. Dark and photocurrent with different illumination time were measured to ascertain the photosensitivity of pure and composite CdS films.

  17. Concentration influence on structural and optical properties of SnO2 thin films synthesized by the spin coating technique.

    NASA Astrophysics Data System (ADS)

    Belhamri, Soumia; Hamdadou, Nasr-Eddine

    2016-10-01

    Tin dioxide is an n-type semiconductor, with wide band gap 3.6 eV and special properties such as high optical transmission in the visible range, the infrared reflection and chemical stability. The objective of our work is to study the effect of solution concentration on the properties of SnO2 thin films, which were deposited on glass substrate by sol-gel spin coating technique and characterized by X-ray diffraction, UV-visible spectroscopy after annealing for one hour at 500°C. X ray diffraction spectra (XRD) showed that the films deposited at different concentrations (0.7 mol/l, 1 mol/l, 1.5 mol/l) are polycrystalline with a rutile type tetragonal. The grains have two preferred orientations along the directions (110) and (101) corresponding to 2θ = 26,744° and 34,113° respectively. We have also noted that the grain size change between 20 and 40 nm. The peak of diffraction becomes less intense when the solution concentration is more than 0.7 mol / l. The opticall transmittance of the films in the visible spectrum was in the range of 59 - 44%.

  18. Fabrication of a thin-layer solid optical tissue phantom by a spin-coating method: pilot study.

    PubMed

    Bae, Yunjin; Son, Taeyoon; Park, Jihoon; Jung, Byungjo

    2013-02-01

    Solid optical tissue phantoms (OTPs) have been widely used for many purposes. This study introduces a spin-coating method (SCM) to fabricate a thin-layer solid OTP (TSOTP) with epidermal thickness. TSOTPs are fabricated by controlling the spin speed (250 to 2500 rpm), absorber concentration (0.2% to 1.0%), and the number of layers. The results show that the thicknesses of the TSOTPs are homogeneous in the region of interest. The one-layer TSOTP achieves maximum and minimum thicknesses of 65±0.28 μm (250 rpm) and 5.1±0.17 μm (2500 rpm), respectively, decreasing exponentially as a function of the spin speed. The thicknesses of the multilayer TSOTPs increases as a function of the number of layers and are correlated strongly with the spin speed (R2≥0.95). The concentration of the OTP mixture does not directly affect the thickness of the TSOTP; however, the absorption coefficients exponentially increase as a function of absorber concentration (R2≥0.98). These results suggest that the SCM can be used to fabricate homogeneous TSOTPs with various thicknesses by controlling the spin speed and number of layers. Finally, a double-layer OTP that combines epidermal TSOTP and dermal OTP is manufactured as a preliminary study to investigate the practical feasibility of TSOTPs.

  19. Ultra-high mobility transparent organic thin film transistors grown by an off-centre spin-coating method.

    PubMed

    Yuan, Yongbo; Giri, Gaurav; Ayzner, Alexander L; Zoombelt, Arjan P; Mannsfeld, Stefan C B; Chen, Jihua; Nordlund, Dennis; Toney, Michael F; Huang, Jinsong; Bao, Zhenan

    2014-01-01

    Organic semiconductors with higher carrier mobility and better transparency have been actively pursued for numerous applications, such as flat-panel display backplane and sensor arrays. The carrier mobility is an important figure of merit and is sensitively influenced by the crystallinity and the molecular arrangement in a crystal lattice. Here we describe the growth of a highly aligned meta-stable structure of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) from a blended solution of C8-BTBT and polystyrene by using a novel off-centre spin-coating method. Combined with a vertical phase separation of the blend, the highly aligned, meta-stable C8-BTBT films provide a significantly increased thin film transistor hole mobility up to 43 cm(2) Vs(-1) (25 cm(2) Vs(-1) on average), which is the highest value reported to date for all organic molecules. The resulting transistors show high transparency of >90% over the visible spectrum, indicating their potential for transparent, high-performance organic electronics.

  20. Effect of tungsten on the electrochromic behaviour of sol-gel dip coated molybdenum oxide thin films

    SciTech Connect

    Dhanasankar, M.; Purushothaman, K.K.; Muralidharan, G.

    2010-05-15

    The paper describes the results obtained on the performance of Mo oxide and mixed W/Mo oxide thin films for possible electrochromic applications. Mo and W/Mo oxide films were deposited on conductive (FTO) glass substrates using sol-gel dip coating method. The films were annealed at 250 {sup o}C for 30 min. The structure and morphology of Mo and W/Mo oxide films were examined using XRD, SEM and EDS. XRD results indicate the amorphous nature of the Mo and W/Mo oxide films annealed for 30 min. The CV measurements revealed that the films prepared with 10 wt.% of tungsten exhibit maximum anodic/cathodic diffusion coefficient of 24.99/12.71 x 10{sup -11} cm{sup 2}/s. The same film exhibits a maximum transmittance variation ({Delta}T%) of 83.4% at 630 nm and 81.06% at 550 nm with the optical density of 1.00 and 1.13 respectively.

  1. High-κ TiO{sub 2} thin film prepared by sol-gel spin-coating method

    SciTech Connect

    Kumar, Arvind; Mondal, Sandip; Rao, K. S. R. Koteswara

    2015-06-24

    High-k TiO{sub 2} thin film on p-type silicon substrate was fabricated by a combined sol-gel and spin coating method. Thus deposited titania film had anatase phase with a small grain size of 16 nm and surface roughness of ≅ 0.6 nm. The oxide capacitance (C{sub ox}), flat band capacitance (C{sub FB}), flat band voltage (V{sub FB}), oxide trapped charge (Q{sub ot}), calculated from the high frequency (1 MHz) C-V curve were 0.47 nF, 0.16 nF, − 0.91 V, 4.7x10{sup −12} C, respectively. As compared to the previous reports, a high dielectric constant of 94 at 1 MHz frequency was observed in the devices investigated here and an equivalent oxide thickness (EOT) was 4.1 nm. Dispersion in accumulation capacitance shows a linear relationship with AC frequencies. Leakage current density was found in acceptable limits (2.1e-5 A/cm{sup 2} for −1 V and 5.7e-7 A/cm{sup 2} for +1 V) for CMOS applications.

  2. Reactive decontamination of absorbing thin film polymer coatings: model development and parameter determination

    NASA Astrophysics Data System (ADS)

    Varady, Mark; Mantooth, Brent; Pearl, Thomas; Willis, Matthew

    2014-03-01

    A continuum model of reactive decontamination in absorbing polymeric thin film substrates exposed to the chemical warfare agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (known as VX) was developed to assess the performance of various decontaminants. Experiments were performed in conjunction with an inverse analysis method to obtain the necessary model parameters. The experiments involved contaminating a substrate with a fixed VX exposure, applying a decontaminant, followed by a time-resolved, liquid phase extraction of the absorbing substrate to measure the residual contaminant by chromatography. Decontamination model parameters were uniquely determined using the Levenberg-Marquardt nonlinear least squares fitting technique to best fit the experimental time evolution of extracted mass. The model was implemented numerically in both a 2D axisymmetric finite element program and a 1D finite difference code, and it was found that the more computationally efficient 1D implementation was sufficiently accurate. The resulting decontamination model provides an accurate quantification of contaminant concentration profile in the material, which is necessary to assess exposure hazards.

  3. Synthesis and Analysis of MnTiO3 Thin Films on ITO Coated Glass Substrates

    NASA Astrophysics Data System (ADS)

    Martin, Emerick; Sahiner, Mehmet-Alper

    Perovskites like Manganese Titanium Oxide have interesting chemical properties that may be advantageous to the development of p-n junction photovoltaic cells. Due to the limited understanding behind the compound, it is essential to know the characteristics of it when it is deposited in thin film form. The cells were created using pulsed laser deposition method for two separate mediums (first layers after ITO). ZnO was deposited onto ITO glass for the first sample. For the second sample, a layer of pure Molybdenum was deposited onto the ITO glass. The MnTiO3 was then deposited onto both samples. There was a target thickness of 1000 Angstroms, but ellipsometry shows that, for the Mo based sample, that film thickness was around 1500 Angstroms. There were inconclusive results for the ZnO based sample. The concentration of active carriers was measured using a Hall Effect apparatus for the Mo based sample. The XRD analyses were used to confirm the perovskite structure of the films. Measurements for photoelectric conversion efficiency were taken using a Keathley 2602 ScourceMeter indicated low values for efficiency. The structural information that is correlated with the low electrical performance of this sample will be discussed. SHU-NJSGC Summer 2015 Fellowship.

  4. Brush-Coated Nanoparticle Polymer Thin Films: structure-mechanical-optical properties

    SciTech Connect

    Green, Peter F.

    2014-08-15

    Our work was devoted to understanding the structure and properties of a class of thin film polymer nanocomposites (PNCs). PNCs are composed of polymer hosts into which nanoparticles (metallic nanoparticles, quantum dots, nanorods, C60, nanotubes) are incorporated. PNCs exhibit a diverse range of functional properties (optical, electronic, mechanical, biomedical, structural), determined in part by the chemical composition of the polymer host and the type of nanoparticle. The properties PNCs rely not only on specific functional, size-dependent, behavior of the nanoparticles, but also on the dispersion, and organizational order in some cases, inter-nanoparticle separation distances, and on relative interactions between the nanoparticles and the host. Therefore the scientific challenges associated with understanding the interrelations between the structure and function/properties of PNCs are far more complex than may be understood based only on the knowledge of the compositions of the constituents. The challenges of understanding the structure-function behavior of PNCs are further compounded by the fact that control of the dispersion of the nanoparticles within the polymer hosts is difficult; one must learn how to disperse inorganic particles within an organic host. The goal of this proposal was to develop an understanding of the connection between the structure and the thermal (glass transition), mechanical and optical properties of a specific class of PNCs. Specifically PNCs composed of polymer chain grafted gold nanoparticles within polymer hosts. A major objective was to understand how to develop basic principles that enable the fabrication of functional materials possessing optimized morphologies and combinations of materials properties.

  5. Mechanical Property Enhancement of Ti-6Al-4V by Multilayer Thin Solid Film Ti/TiO2 Nanotubular Array Coating for Biomedical Application

    NASA Astrophysics Data System (ADS)

    Zalnezhad, Erfan; Baradaran, Saeid; Bushroa, A. R.; Sarhan, Ahmed A. D.

    2014-02-01

    With the intention of improving the mechanical properties of Ti-6Al-4V, samples were first coated with pure titanium using the physical vapor deposition (PVD) magnetron sputtering technique. The Taguchi optimization method was used to attain a higher coating on substrate adhesion. Second, pure titanium-coated samples with higher adhesion were anodized to generate TiO2 nanotubes. Next, the TiO2-coated specimens were heat treated at annealing temperatures of 753.15 K and 923.15 K (480 °C and 650 °C). The XRD results indicate that the varying heat treatment temperatures produced different phases, namely, anatase [753.15 K (480 °C)] and rutile [923.15 K (650 °C)]. Finally, the coated samples' mechanical properties (surface hardness, adhesion, and fretting fatigue life) were investigated. The fretting fatigue lives of TiO2-coated specimens at 753.15 K and 923.15 K (480 °C and 650 °C) annealing temperatures were significantly enhanced compared to uncoated samples at low and high cyclic fatigue. The results also indicate that TiO2-coated samples heat treated at an annealing temperature of 753.15 K (480 °C) (anatase phase) are more suitable for increasing fretting fatigue life at high cyclic fatigue (HCF), while at low cyclic fatigue, the annealing temperature of 923.15 K (650 °C) seemed to be more appropriate. The fretting fatigue life enhancement of thin-film TiO2 nanotubular array-coated Ti-6Al-4V is due to the ceramic nature of TiO2 which produces a hard surface as well as a lower coefficient of friction of the TiO2 nanotube surface that decreases the fretting between contacting components, namely, the sample and friction pad surfaces.

  6. Computational study of low-friction quasicrystalline coatings via simulations of thin film growth of hydrocarbons and rare gases

    NASA Astrophysics Data System (ADS)

    Setyawan, Wahyu

    Quasicrystalline compounds (QC) have been shown to have lower friction compared to other structures of the same constituents. The abscence of structural interlocking when two QC surfaces slide against one another yields the low friction. To use QC as low-friction coatings in combustion engines where hydrocarbon-based oil lubricant is commonly used, knowledge of how a film of lubricant forms on the coating is required. Any adsorbed films having non-quasicrystalline structure will reduce the self-lubricity of the coatings. In this manuscript, we report the results of simulations on thin films growth of selected hydrocarbons and rare gases on a decagonal Al73Ni10Co17 quasicrystal (d-AlNiCo). Grand canonical Monte Carlo method is used to perform the simulations. We develop a set of classical interatomic many-body potentials which are based on the embedded-atom method to study the adsorption processes for hydrocarbons. Methane, propane, hexane, octane, and benzene are simulated and show complete wetting and layered films. Methane monolayer forms a pentagonal order commensurate with the d-AlNiCo. Propane forms disordered monolayer. Hexane and octane adsorb in a close-packed manner consistent with their bulk structure. The results of hexane and octane are expected to represent those of longer alkanes which constitute typical lubricants. Benzene monolayer has pentagonal order at low temperatures which transforms into triangular lattice at high temperatures. The effects of size mismatch and relative strength of the competing interactions (adsorbate-substrate and between adsorbates) on the film growth and structure are systematically studied using rare gases with Lennard-Jones pair potentials. It is found that the relative strength of the interactions determines the growth mode, while the structure of the film is affected mostly by the size mismatch between adsorbate and substrate's characteristic length. On d-AlNiCo, xenon monolayer undergoes a first-order structural

  7. Regulation of the forming process and the set voltage distribution of unipolar resistance switching in spin-coated CoFe2O4 thin films.

    PubMed

    Mustaqima, Millaty; Yoo, Pilsun; Huang, Wei; Lee, Bo Wha; Liu, Chunli

    2015-01-01

    We report the preparation of (111) preferentially oriented CoFe2O4 thin films on Pt(111)/TiO2/SiO2/Si substrates using a spin-coating process. The post-annealing conditions and film thickness were varied for cobalt ferrite (CFO) thin films, and Pt/CFO/Pt structures were prepared to investigate the resistance switching behaviors. Our results showed that resistance switching without a forming process is preferred to obtain less fluctuation in the set voltage, which can be regulated directly from the preparation conditions of the CFO thin films. Therefore, instead of thicker film, CFO thin films deposited by two times spin-coating with a thickness about 100 nm gave stable resistance switching with the most stable set voltage. Since the forming process and the large variation in set voltage have been considered as serious obstacles for the practical application of resistance switching for non-volatile memory devices, our results could provide meaningful insights in improving the performance of ferrite material-based resistance switching memory devices.

  8. Annealing time dependence of the physical, electrical and pH response characteristics of spin coated TiO2 thin films

    NASA Astrophysics Data System (ADS)

    Zulkefle, M. A.; Rahman, R. A.; Yusoff, K. A.; Abdullah, W. F. H.; Rusop, M.; Herman, S. H.

    2015-11-01

    Titanium dioxide (TiO2) thin film was deposited on indium tin oxide (ITO) substrate and used as sensing membrane of EGFET pH sensor. The thin film was fabricated using sol- gel spin coating method. All samples were annealed at 400 °C but the annealing time was varied. This is done to study the effects of annealing time on physical and electrical properties of titanium dioxide thin film. The sensitivity of each sample towards H+ ion was measured and result shows that sample annealed for 45 minutes has the highest sensitivity (52.6 mV/pH). It is found that increasing annealing duration will increase the pH sensitivity but a limit will be reached at certain point. Longer annealing processes done beyond this point will results in lower pH sensitivity.

  9. Sol-gel deposited aluminum-doped and gallium-doped zinc oxide thin-film transparent conductive electrodes with a protective coating of reduced graphene oxide

    NASA Astrophysics Data System (ADS)

    Zhu, Zhaozhao; Mankowski, Trent; Balakrishnan, Kaushik; Shikoh, Ali Sehpar; Touati, Farid; Benammar, Mohieddine A.; Mansuripur, Masud; Falco, Charles M.

    2016-04-01

    Using a traditional sol-gel deposition technique, we successfully fabricated aluminum-doped zinc oxide (AZO) and gallium-doped zinc oxide (GZO) thin films on glass substrates. Employing a plasma treatment method as the postannealing process, we produced thin-film transparent conductive electrodes exhibiting excellent optical and electrical properties, with transmittance greater than 90% across the entire visible spectrum and the near-infrared range, as well as good sheet resistance under 200 Ω/sq. More importantly, to improve the resilience of our fabricated thin-film samples at elevated temperatures and in humid environments, we deposited a layer of reduced graphene oxide (rGO) as protective overcoating. The stability of our composite AZO/rGO and GZO/rGO samples improved substantially compared to that of their counterparts with no rGO coating.

  10. Effect of Fe incorporation on the optical behavior of ZnO thin films prepared by sol-gel derived spin coating techniques

    NASA Astrophysics Data System (ADS)

    Rakkesh, R. Ajay; Malathi, R.; Balakumar, S.

    2013-02-01

    In this work, Fe doped Zinc Oxide (ZnO) thin films were fabricated on the glass substrate by sol-gel derived spin coating technique. X-ray Diffraction studies revealed that the obtained pure and Fe doped ZnO thin films were in the wurtzite and spinel phase respectively. The three well defined Raman lines at 432, 543 and 1091 cm-1 also confirmed the lattice structure of the ZnO thin film has wurtzite symmetry. While doping Fe atoms in the ZnO, there was a significant change in the phase from wurtzite to spinel structure; owing to Fe (III) ions being incorporated into the lattice through substitution of Zn (II) ions. Room temperature PL spectra showed that the role of defect mediated red emissions at 612 nm was due to radial recombination of a photogenerated hole with an electron that belongs to the Fe atoms, which were discussed in detail.

  11. Metal separations using aqueous biphasic partitioning systems

    SciTech Connect

    Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.; Vojta, Y.; Gartelmann, J.; Mego, W.

    1996-05-01

    Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.

  12. Biphasic Pulmonary Blastoma Associated with Cerebral Metastasis.

    PubMed

    Kilic, Dalokay; Yilmaz, Cem; Tepeoglu, Merih; Vural, Cigdem; Caner, Hakan

    2016-01-01

    Pulmonary blastoma is a very rare malignant tumor of the lungs. A biphasic pulmonary blastoma was histologically diagnosed by a characteristic finding as it was mainly constituted of immature tumor tissue that had both epithelial and mesenchymal components. We present a case of a 68-year-old man with biphasic pulmonary blastoma. The patient underwent cranial metastatectomy and left lung upper lobectomy. Although the tumor was resected, there was rapid metastasis to the cranial, liver, kidney and multiple bones. Although radiotherapy and chemotherapy were administrated, the patient died about 6 months postoperatively. Close follow-up and aggressive chemotherapy should be considered for such tumours. In the light of this case, the authors review the pathologic, clinical, radiological and therapeutic features of this very rare malignant lung tumor.

  13. Biomimetic biphasic scaffolds for osteochondral defect repair

    PubMed Central

    Li, Xuezhou; Ding, Jianxun; Wang, Jincheng; Zhuang, Xiuli; Chen, Xuesi

    2015-01-01

    The osteochondral defects caused by vigorous trauma or physical disease are difficult to be managed. Tissue engineering provides a possible option to regenerate the damaged osteochondral tissues. For osteochondral reconstruction, one intact scaffold should be considered to support the regeneration of both cartilage and subchondral bone. Therefore, the biphasic scaffolds with the mimic structures of osteochondral tissues have been developed to close this chasm. A variety of biomimetic bilayer scaffolds fabricated from natural or synthetic polymers, or the ones loading with growth factors, cells, or both of them make great progresses in osteochondral defect repair. In this review, the preparation and in vitro and/or in vivo verification of bioinspired biphasic scaffolds are summarized and discussed, as well as the prospect is predicted. PMID:26816644

  14. Slurry spin coating of thin film yttria stabilized zirconia/gadolinia doped ceria bi-layer electrolytes for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Joong; Kim, Manjin; Neoh, Ke Chean; Han, Gwon Deok; Bae, Kiho; Shin, Jong Mok; Kim, Gyu-Tae; Shim, Joon Hyung

    2016-09-01

    Thin ceramic bi-layered membrane comprising yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC) is fabricated by the cost-effective slurry spin coating technique, and it is evaluated as an electrolyte of solid oxide fuel cells (SOFCs). It is demonstrated that the slurry spin coating method is capable of fabricating porous ceramic films by adjusting the content of ethyl-cellulose binders in the source slurry. The porous GDC layer deposited by spin coating under an optimal condition functions satisfactorily as a cathode-electrolyte interlayer in the test SOFC stack. A 2-μm-thick electrolyte membrane of the spin-coated YSZ/GDC bi-layer is successfully deposited as a dense and stable film directly on a porous NiO-YSZ anode support without any interlayers, and the SOFC produces power output over 200 mW cm-2 at 600 °C, with an open circuit voltage close to 1 V. Electrochemical impedance spectra analysis is conducted to evaluate the performance of the fuel cell components in relation with the microstructure of the spin-coated layers.

  15. Selective light emission in nonbonding electron transitions in poly(vinyl pyrrolidone) molecules on spin-coating in thin layers.

    PubMed

    Mishra, A; Ram, S

    2009-12-24

    It is shown that polymer molecules of poly(vinyl pyrrolidone) (PVP) rearranged in thin layers present surface-enhanced light emission in selective bands over a wide 260-860 nm range of spectrum. Four bands occur in spin-coated films by a dilute solution in water at 288, 395, 560, and 760 nm upon irradiating with an ultraviolet 200-250 nm light. The second and third bands are strong by contributing 82% intensity of the spectrum. Randomly dispersed PVP molecules in solution exhibit a single band (broad) at 425 nm {pi(0) <-- n(1)pi(2)* transition in the nonbonding electrons n(1) in the C=O (2s(2)p(4)) group of pyrrolidone ring} and a harmonic band 650-860 nm (weak) of roughly twice its wavelength. In films, this band is split up into two well-separated pi(0) <-- n(1)pi(2)* (395 nm) and pi(0) <-- n(2)pi(1)* (560 nm) bands. Localized nonbonding electrons n(2) of the C-N (2s(2)p(3)) moiety of pyrrolidone ring excite and emit part of the energy in the pi(0) <-- n(2)pi(1)* transition with as much intensity as in the pi(0) <-- n(1)pi(2)* band. Localization of n(1) and n(2) electrons on molecular layers of films favors the resonance >N-C=O structure with three C=O stretching bands 1615, 1635, and 1665 cm(-1) against a single band 1638 cm(-1) in randomly dispersed molecules (solution). The C-N stretching frequency is decreased by 30 cm(-1). Results are useful for molecular designing of optical films for down-energy conversion, optical switching, and biological sensors.

  16. Growth and physical properties of p-Zn x Cd1- x S thin films thermally evaporated on ITO-coated glass substrates

    NASA Astrophysics Data System (ADS)

    Yoon, Eun Jeong; Han, Dong Hun; Lee, Jeoung Ju; Lee, Jong Duk; Kang, Kwang Yong; Lee, Seung Hwan; Shewale, Prashant Shivaji

    2015-01-01

    Zn x Cd1- x S ( x = 0.15, 0.44, 0.62, 0.80, and 0.95) thin films of about 340 nm in thickness were deposited on indium-tin-oxide (ITO)-coated glass substrates by using thermal evaporation of high-purity ZnS and CdS mixed tablets in high vacuum. X-ray diffraction spectra showed that the Zn x Cd1- x S thin films were preferentially grown along the (111) orientation. The Zn x Cd1- x S crystal structure was a mixture structure of the ZnS and the CdS cubic zincblende structures with lattice constants a = 5.670 Å to a = 5.734 Å for CdS and a = 5.437 Å for ZnS. The ( αh ν)2 vs. h ν plots for the Zn x Cd1- x S thin films showed that all samples had direct transition band gaps. The energy band gaps of the Zn x Cd1- x S thin films increased monotonically from 2.45 eV for x = 0.15 to 3.37 eV for x = 0.95. The dynamical behavior of the charge carriers in the Zn x Cd1- x S thin films was investigated by using the photoinduced discharge characteristics (PIDC) technique.

  17. Effect of co doping to the optical properties of ZnO:Co Thin films deposited on glass substrate by sol-gel spray coating technique

    NASA Astrophysics Data System (ADS)

    Marito Siagian, Sinta; Sutanto, Heri; Permatasari, Anes

    2017-01-01

    This study aims are to analyze the effect of cobalt doping concentration to the optical properties ZnO:Co thin films deposited by using sol-gel spray coating technique. Deposition of ZnO and ZnO:Co thin films has been successfully formed on a glass substrate using sol-gel method of spray coating technique with a variation of doping Co as much as 3%, 5%, 7%, 9%, and 11%. Solution of ZnO:Co synthesized by mixing zinc acetate dehydrate (Zn (COOCH3)2.2H2O into a isopropanol ((CH3)2CHOH) then monoethanolamine (MEA) and cobalt nitrate are added as a dopant at room temperature, then ZnO:Co sprayed on a glass substrate that has been heated at a temperature of 450°C. A thin film further characterized using spectrophotometer Uv-Vis to determine the value of absorbance and transmittance. Energy band gap was determined by using tauc plot that uses the absorbance value. The results show that there has been a difference in the value of the Energy band gap of ZnO with and without of Co doping. The addition of Co doping causes the decrease of small energy band gap. The magnitude of the energy band gap of thin films of ZnO is 3.337 eV and ZnO:Co 3% is 3.129 eV. Thin film that has narrower band gap was applied for material photocatalyst

  18. Polyacrylonitrile block copolymers for the preparation of a thin carbon coating around TiO2 nanorods for advanced lithium-ion batteries.

    PubMed

    Oschmann, Bernd; Bresser, Dominic; Tahir, Muhammad Nawaz; Fischer, Karl; Tremel, Wolfgang; Passerini, Stefano; Zentel, Rudolf

    2013-11-01

    Herein, a new method for the realization of a thin and homogenous carbonaceous particle coating, made by carbonizing RAFT polymerization derived block copolymers anchored on anatase TiO2 nanorods, is presented. These block copolymers consist of a short anchor block (based on dopamine) and a long, easily graphitizable block of polyacrylonitrile. The grafting of such block copolymers to TiO2 nanorods creates a polymer shell, which can be visualized by atomic force microscopy (AFM). Thermal treatment at 700 °C converts the polyacrylonitrile block to partially graphitic structures (as determined by Raman spectroscopy), establishing a thin carbon coating (as determined by transmission electron microscopy, TEM, analysis). The carbon-coated TiO2 nanorods show improved electrochemical performance in terms of achievable specific capacity and, particularly, long-term cycling stability by reducing the average capacity fading per cycle from 0.252 mAh g(-1) to only 0.075 mAh g(-1) .

  19. Biphasic and boundary lubrication mechanisms in artificial hydrogel cartilage: A review.

    PubMed

    Murakami, Teruo; Yarimitsu, Seido; Nakashima, Kazuhiro; Sakai, Nobuo; Yamaguchi, Tetsuo; Sawae, Yoshinori; Suzuki, Atsushi

    2015-12-01

    Various studies on the application of artificial hydrogel cartilage to cartilage substitutes and artificial joints have been conducted. It is expected in clinical application of artificial hydrogel cartilage that not only soft-elastohydrodynamic lubrication but biphasic, hydration, gel-film and boundary lubrication mechanisms will be effective to sustain extremely low friction and minimal wear in daily activities similar to healthy natural synovial joints with adaptive multimode lubrication. In this review article, the effectiveness of biphasic lubrication and boundary lubrication in hydrogels in thin film condition is focused in relation to the structures and properties of hydrogels. As examples, the tribological behaviors in three kinds of poly(vinyl alcohol) hydrogels with high water content are compared, and the importance of lubrication mechanism in biomimetic artificial hydrogel cartilage is discussed to extend the durability of cartilage substitute.

  20. Comparison of single-biphasic versus sequential-biphasic shocks on defibrillation threshold in pigs.

    PubMed

    Csanadi, Z; Jones, D L; Wood, G K; Klein, G J

    1997-06-01

    Current generation implantable cardioverter defibrillators use monophasic, biphasic, or sequential pulse shocks, most of which truncate after a given time, dumping the remaining charge on the capacitor through an internal resistor. We hypothesized that having an additional current pathway, and delivering the majority of the remaining charge on a single capacitor to the two pathways using additional shock phases, would improve defibrillation efficacy. This hypothesis was tested by comparing DFTs using a simulated single capacitor, single-biphasic shock (two 5-ms pulses separated by 0.2 ms), delivered to coupled pairs of electrodes, to those using a sequential-biphasic shock (four 5-ms pulses separated by 0.2 ms) delivered to separate opposing electrodes, delivered from the same electrodes for both waveforms. In eight open-chest anesthetized pigs, four mesh electrodes (Medtronic TX-7, 6.5 cm2), were sutured on the epicardium of the anterior and posterior surfaces of each ventricle. Shocks were delivered from a 200-microF capacitor bank. Triplicate DFTs were obtained using each waveform in a randomized crossover design. Initial leading edge voltage (mean +/- SEM: 420 +/- 33 V vs 497 +/- 34 V; P < 0.05), initial peak current (4.8 +/- 0.4 A vs 13 +/- 1.1 A; P < 0.001), and delivered energy (16.9 +/- 2.6 J vs 30.4 +/- 5.3 J; P < 0.05) at the DFT were all significantly lower using sequential-biphasic shocks than those using single-biphasic shocks, respectively. We conclude that for direct heart defibrillation, it is worthwhile to combine sequential capability to biphasic shocks and deliver the remaining charge on the capacitor to the two different pathways.

  1. The enhanced photocatalytic activity and self-cleaning properties of mesoporous SiO2 coated Cu-Bi2O3 thin films.

    PubMed

    Shan, Wenjie; Hu, Yun; Zheng, Mengmeng; Wei, Chaohai

    2015-04-28

    Mesoporous SiO2 coated Cu-Bi2O3 thin films (meso-SiO2/Cu-Bi2O3) were prepared on glass substrates using a simple sol-gel/spin-coating method. The structure and optical properties were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, a UV-vis spectrophotometer and a water contact angle meter. The photocatalytic activity and self-cleaning properties of the films were investigated through the degradation of methyl orange and stearic acid, respectively. It was found that the meso-SiO2/Cu-Bi2O3 thin films were highly transparent and showed excellent superhydrophilicity even in the dark. The thin films exhibited enhanced photocatalytic activity and self-cleaning properties compared to pure Bi2O3 films, which was attributed to the cooperation of the interfacial charge transfer between Bi2O3 and surface Cu species as well as the unique mesoporous SiO2 structure. The results showed that the films can be used as promising self-cleaning and antifogging materials.

  2. Field emission of silicon emitter arrays coated with sol-gel (Ba0.65Sr0.35)1-xLaxTiO3 thin films

    NASA Astrophysics Data System (ADS)

    Lu, H.; Pan, J. S.; Chen, X. F.; Zhu, W. G.

    2007-07-01

    (Ba0.65Sr0.35)1-xLaxTiO3 (BSLT) thin films with different La concentrations have been deposited on Si field emitter arrays (FEAs) using sol-gel technology for field electron emission applications. The films exhibit the perovskite structure at low La substitution level (x ≤0.5) and the pyrochlore phase at high La concentration (x ≥0.75). The 30-nm-thick BSLT (x =0.25) thin film has higher crystallinity of perovskite structure in the surface region. An x-ray photoelectron spectroscopy study indicates that the oxygen vacancy concentration decreases with La substitution. With respect to the undoped Ba0.65Sr0.35TiO3 thin film, the Fermi level shifts down for the BSLT sample with x =0.1 ascribed to the decreasing oxygen vacancy concentration, and then shifts up for the BSLT sample with x =0.25 attributed to the increasing La substitution level. In highly doped films with an x value over 0.5, it shifts down again associated with the second pyrochlore phase formation. The best enhancement in field emission is found for the BSLT-coated (x =0.25) Si FEAs due to the improved perovskite structure in the surface region and up-moved Fermi level of the coating.

  3. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces.

    PubMed

    Wijesinghe, W P S L; Mantilaka, M M M G P G; Chathuranga Senarathna, K G; Herath, H M T U; Premachandra, T N; Ranasinghe, C S K; Rajapakse, R P V J; Rajapakse, R M G; Edirisinghe, Mohan; Mahalingam, S; Bandara, I M C C D; Singh, Sanjleena

    2016-06-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO2 thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value.

  4. Electrical investigation of TiO2 thin films coated on glass and silicon substrates—effect of UV and visible light illumination

    NASA Astrophysics Data System (ADS)

    Amirtharajan, Saranya; Jeyaprakash, Pandiarajan; Natarajan, Jeyakumaran; Natarajan, Prithivikumaran

    2016-04-01

    The conducting nature of nanocrystalline TiO2 thin film coated on glass and silicon (Si) substrates was studied in detail. The films were prepared through sol-gel spin-coating method with variation in coating parameters viz, the thickness of the film and the post annealing temperature. The thickness of the films was measured using Stylus profilometer. The resistivity of the film, as a function of film thickness, under the illumination of UV, visible light, and dark conditions was found using the four-probe method. The results show that the resistivity of the film decreases with increase in thickness of the film. The decrease in resistivity of the film is attributed to increase in cross-sectional area and rearrangement and removal of defects. Illumination of the samples under visible and UV light further decreases the resistivity of the film. The electrical resistivity of TiO2 film coated on Si substrate was observed to be lesser than that of the glass substrate.

  5. Optical Thin Film Coatings

    DTIC Science & Technology

    1981-06-01

    metal silicides which may be of interest for computer memories. This ion-bombardment/alloying process is far superior to the more common thermal...mirrors, which are replicated on a beryllium sub- strate. Many of Jobin-Yvon’s larger gratings are also produced by replication, both in France and at

  6. Influence of annealing on p-type Cu2ZnSnS4 thin film by dip coating solution growth technique for the application of solar cell

    NASA Astrophysics Data System (ADS)

    Maheshwari, B. Uma; Senthil Kumar, V.

    2014-09-01

    Thin films of Cu2ZnSnS4 have been deposited by solution growth dip coating method. Different Cu/Zn/Sn/S molar ratios were applied, which tells the properties of copper, Zinc, Tin, and Sulfide using X-ray diffraction, UV-vis, Energy dispersive X-ray spectroscopy, and scanning electron spectroscopy. The pure CZTS thin film showed the phase transformation from Kesterite (tetragonal) to Kesterite (orthorhombic) crystal structure. Optical measurement analysis reveals that layers have relatively high absorption coefficient in the visible spectrum with a band gap reduction of 1.51-1.49 eV with an increase in the annealing temperature from room temperature to 300 °C for 1 h in hot air furnace without any presence of an inert gas. Optical conductivity was observed to increase from 1012 to 1013 (sec)-1 and electrical conductivity was of the order of 102 (Ω cm)-1.

  7. Refractometric sensors based on multimode interference in a thin-film coated single-mode-multimode-single-mode structure with reflection configuration.

    PubMed

    Del Villar, Ignacio; Socorro, Abian B; Corres, Jesus M; Arregui, Francisco J; Matias, Ignacio R

    2014-06-20

    Thin-film coated single-mode-multimode-single-mode (SMS) structures have been analyzed both theoretically and experimentally with the aim of detecting different refractive indices. By adequate selection of the thickness of the thin film and of the diameter of the multimode segment in the SMS structure, a seven-fold improvement can be obtained in the sensitivity of the device to the surrounding medium refractive index, achieving a maximum sensitivity of 1199.18  nm/refractive index unit for the range of refractive indices from 1.321 to 1.382. Using layer-by-layer self-assembly for deposition, both on the cladding and on the tip of the multimode segment, allows the reflected power to increase, which avoids the application of a mirror on the tip of the multimode segment.

  8. Structural, optical, morphological and electrical properties of undoped and Al-doped ZnO thin films prepared using sol—gel dip coating process

    NASA Astrophysics Data System (ADS)

    Boukhenoufa, N.; Mahamdi, R.; Rechem, D.

    2016-11-01

    In this work, sol—gel dip-coating technique was used to elaborate ZnO pure and ZnO/Al films. The impact of Al-doped concentration on the structural, optical, surface morphological and electrical properties of the elaborated samples was investigated. It was found that better electrical and optical performances have been obtained for an Al concentration equal to 5%, where the ZnO thin films exhibit a resistivity value equal to 1.64104 Ω·cm. Moreover, highest transparency has been recorded for the same Al concentration value. The obtained results from this investigation make the developed thin film structure a potential candidate for high optoelectronic performance applications.

  9. RuO2 thin films deposited by spin coating on silicon substrates: pH-dependence of the microstructure and catalytic properties.

    PubMed

    Nowakowski, P; Kopia, A; Villain, S; Fremy, M-A; Kusinski, J; Gavarri, J-R

    2010-03-01

    RuO(2) thin films have been deposited on Si substrates by spin coating with precursor solutions having a pH varying between 1.4 and 4. X-ray diffraction and transmission electron microscopy analyses are used to determine correlations between the solution pH and the film microstructure. As the pH varies, the RuO(2) crystal sizes reach a minimum value then increase; the porosity increases at the substrate/film interface with formation of large cavities. The catalytic activity of these RuO(2) layers in the presence of flowing air-methane is analysed by Fourier transform infrared spectroscopy of the conversion of CH(4) into CO(2). The increasing porosity seems to improve the catalytic conversion rate of methane. Electrical impedance spectroscopy analyses show that the conductivity strongly depends on the thin-film microstructure and porosity.

  10. Enhancement of the critical current density in FeO-coated MgB2 thin films at high magnetic fields

    PubMed Central

    Surdu, Andrei E; Hamdeh, Hassan H; Al-Omari, I A; Sellmyer, David J; Socrovisciuc, Alexei V; Prepelita, Andrei A; Koparan, Ezgi T; Yanmaz, Ekrem; Ryazanov, Valery V; Hahn, Horst

    2011-01-01

    Summary The effect of depositing FeO nanoparticles with a diameter of 10 nm onto the surface of MgB2 thin films on the critical current density was studied in comparison with the case of uncoated MgB2 thin films. We calculated the superconducting critical current densities (J c) from the magnetization hysteresis (M–H) curves for both sets of samples and found that the J c value of FeO-coated films is higher at all fields and temperatures than the J c value for uncoated films, and that it decreases to ~105 A/cm2 at B = 1 T and T = 20 K and remains approximately constant at higher fields up to 7 T. PMID:22259764

  11. Sol-gel spin coated well adhered MoO3 thin films as an alternative counter electrode for dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Mutta, Geeta R.; Popuri, Srinivasa R.; Wilson, John I. B.; Bennett, Nick S.

    2016-11-01

    In this work, we aim to develop a viable, inexpensive and non-toxic material for counter electrodes in dye sensitized solar cells (DSSCs). We employed an ultra-simple synthesis process to deposit MoO3 thin films at low temperature by sol-gel spin coating technique. These MoO3 films showed good transparency. It is predicted that there will be 150 times reduction of precursors cost by realizing MoO3 thin films as a counter electrode in DSSCs compared to commercial Pt. We achieved a device efficiency of about 20 times higher than that of the previous reported values. In summary we develop a simple low cost preparation of MoO3 films with an easily scaled up process along with good device efficiency. This work encourages the development of novel and relatively new materials and paves the way for massive reduction of industrial costs which is a prime step for commercialization of DSSCs.

  12. Structural properties 3,16-bis triisopropylsilylethynyl (pentacene) (TIPS-pentacene) thin films onto organic dielectric layer using slide coating method

    SciTech Connect

    Rusnan, Fara Naila; Mohamad, Khairul Anuar; Seria, Dzul Fahmi Mohd Husin; Saad, Ismail; Ghosh, Bablu K.; Alias, Afishah

    2015-08-28

    3,16-bis triisopropylsilylethynyl (Pentacene) (TIPS-Pentacene) compactable interface property is important in order to have a good arrangement of molecular structure. Comparison for TIPS-Pentacene deposited between two different surface layers conducted. 0.1wt% TIPS-Pentacene diluted in chloroform were deposited onto poly(methylmeaclyrate) (PMMA) layered transparent substrates using slide coating method. X-ray diffraction (XRD) used to determine crystallinity of thin films. Series of (00l) diffraction peaks obtained with sharp first peaks (001) for TIPS-Pentacene deposited onto PMMA layer at 5.35° and separation of 16.3 Å. Morphology and surface roughness were carried out using scanning electron microscope (SEM) and surface profilemeter LS500, respectively.TIPS-Pentacene deposited onto PMMA layer formed needled-like-shape grains with 10.26 nm surface roughness. These properties were related as thin film formed and its surface roughness plays important role towards good mobility devices.

  13. Soil decontamination using aqueous biphasic separation

    SciTech Connect

    Chaiko, D.J.; Mensah-Biney, R.; Gupta, D.

    1994-02-01

    This paper summarizes efforts to develop a biphasic extraction process for separating ultrafine particulate contaminants from soils having high amounts of silt and clay. This work has thus far dealt with the removal of refractory uranium particles from the soils at Fernald, Ohio. The separation process involves the selective partitioning of ultra-fine particles between two immiscible aqueous phases. The authors have conducted batch extraction studies and are now beginning to scaleup the process for pilot-plant testing at Argonne National Laboratory (ANL). The results of these extraction studies are discussed.

  14. Structural, optical, and electrical properties of ZnO thin films deposited by sol-gel dip-coating process at low temperature

    NASA Astrophysics Data System (ADS)

    Kim, Soaram; Nam, Giwoong; Yoon, Hyunsik; Park, Hyunggil; Choi, Hyonkwang; Kim, Jong Su; Kim, Jin Soo; Kim, Do Yeob; Kim, Sung-O.; Leem, Jae-Young

    2014-07-01

    Sol-gel dip-coating was used to prepare ZnO thin films with relaxed residual stress by lowering the deposition temperature from room temperature (25°C) to -25°C. The effect of deposition temperature on the structural, optical, and electrical properties of the films was characterized using scanning electron microscopy (SEM), Raman spectroscopy, photoluminescence (PL), ultraviolet-visible (UV-Vis) spectroscopy and reflectance accessory, and the van der Pauw method. All the thin films were deposited successfully onto quartz substrates and exhibited fibrous root morphology. At low temperature, the deposition rate was higher than at room temperature (RT) because of enhanced viscosity of the films. Further, lowering the deposition temperature affected the structural, optical, and electrical properties of the ZnO thin films. The surface morphology, residual stress, PL properties, and optical transmittance and reflectance of the films were measured, and this information was used to determine the absorption coefficient, optical band gap, Urbach energy, refractive index, refractive index at infinite wavelength, extinction coefficient, single-oscillator energy, dispersion energy, average oscillator wavelength, moments M -1 and M -3, dielectric constant, optical conductivity, and electrical resistivity of the ZnO thin films.

  15. Thickness Dependent Structural and Dielectric Properties of Calcium Copper Titanate Thin Films Produced by Spin-Coating Method for Microelectronic Devices

    NASA Astrophysics Data System (ADS)

    Thiruramanathan, P.; Sankar, S.; Marikani, A.; Madhavan, D.; Sharma, Sanjeev K.

    2017-03-01

    Calcium copper titanate (CaCu3Ti4O12, CCTO) thin films have been deposited on platinized silicon [(111)Pt/Ti/SiO2/Si] substrate through a sol-gel spin coating technique and annealed at 600-900°C with a variation of 100°C per sample for 3 h. The activation energy for crystalline growth, as well as optimal annealing temperature (900°C) of the CCTO crystallites was studied by x-ray diffraction analysis (XRD). Thickness dependent structural, morphological, and optical properties of CCTO thin films were observed. The field emission scanning electron microscopy (FE-SEM) verified that the CCTO thin films are uniform, fully covered, densely packed, and the particle size was found to be increased with film thickness. Meanwhile, quantitative analysis of dielectric properties (interfacial capacitance, dead layers, and bulk dielectric constant) of CCTO thin film with metal-insulator-metal (M-I-M) structures has been investigated systematically using a series capacitor model. Room temperature dielectric properties of all the samples exhibit dispersion at low frequencies, which can be explained based on Maxwell-Wagner two-layer models and Koop's theory. It was found that the 483 nm thick CCTO film represents a high dielectric constant (ɛ r = 3334), low loss (tan δ = 3.54), capacitance (C = 4951 nF), which might satisfy the requirements of embedded capacitor.

  16. Nanoporous TiO2/polyion thin-film-coated long-period grating sensors for the direct measurement of low-molecular-weight analytes.

    PubMed

    Yang, Rui-Zhu; Dong, Wen-Fei; Meng, Xiang; Zhang, Xu-Lin; Sun, Yun-Lu; Hao, Ya-Wei; Guo, Jing-Chun; Zhang, Wen-Yi; Yu, Yong-Sen; Song, Jun-Feng; Qi, Zhi-Mei; Sun, Hong-Bo

    2012-06-12

    We present novel nanoporous TiO(2)/polyion thin-film-coated long-period fiber grating (LPFG) sensors for the direct measurement of low-molecular-weight chemicals by monitoring the resonance wavelength shift. The hybrid overlay films are prepared by a simple layer-by-layer deposition approach, which is mainly based on the electrostatic interaction of TiO(2) nanoparticles and polyions. By the alternate immersion of LPFG into dispersions of TiO(2) nanoparticles and polyions, respectively, the so-formed TiO(2)/polyion thin film exhibits a unique nanoporous internal structure and has a relative higher refractive index than LPFG cladding. In particular, the porosity of the thin film reduces the diffusion coefficient and enhances the permeability retention of low-molecular-weight analytes within the porous film. The increases in the refractive index of the LPFG overlay results in a distinguished modulation of the resonance wavelength. Therefore, the detection sensitivity of LPFG sensors has been greatly improved, according to theoretical simulation. After the structure of the TiO(2)/polyion thin film was optimized, glucose solutions as an example with a low concentration of 10(-7) M was easily detected and monitored at room temperature.

  17. Thin carbon layer coated Ti3+-TiO2 nanocrystallites for visible-light driven photocatalysis

    NASA Astrophysics Data System (ADS)

    Jiang, Baojiang; Tang, Yunqi; Qu, Yang; Wang, Jian-Qiang; Xie, Ying; Tian, Chungui; Zhou, Wei; Fu, Honggang

    2015-03-01

    Black TiO2 containing Ti3+ attracts enormous attention due to its excellent visible-light driven photocatalytic activity. Herein, an in situ thermal decomposition approach to synthesize uniform thin carbon coated Ti3+-TiO2 nanocrystals is presented. During the oleic acid-assisted solvothermal process, the crystal size and morphology of TiO2 were controlled through oleic acid with carboxylic acid groups. Then the residual small quantities of oleic acid anchored on TiO2 were used as a carbon source, which could be in situ pyrolyzed into a carbon layer on TiO2 at high temperature and under an inert atmosphere. Meanwhile, Ti4+ species were partly reduced into Ti3+ states/oxygen vacancies on the surface of TiO2 due to the carbothermal reduction reaction for the carbon-encapsulated Ti3+-TiO2 structure. A series of characterizations indicated that the 20-25 nm TiO2 nanocrystals obtained were wrapped evenly by 1-2 nm carbon layers, which had an important effect on the energy band structure change of TiO2. The presence of the carbon layer also improves the Ti3+ stability and the conduction behavior of the composites. The Ti3+ states/oxygen vacancies created on the surface of TiO2 were responsible for the remarkable photogenerated charge separation and extended visible-light absorption range. Furthermore, Ti3+ states/oxygen vacancies and the carbon layer together could enhance the adsorption ability of O2 so as to promote the photogenerated electrons captured by the adsorbed O2, leading to a great increase in the charge separation. As a result, the composites exhibit high photocatalytic performance for organic pollutants under visible light irradiation. This simple and new method may pave the way to practical applications for efficient photocatalytic degradation under visible light.Black TiO2 containing Ti3+ attracts enormous attention due to its excellent visible-light driven photocatalytic activity. Herein, an in situ thermal decomposition approach to synthesize uniform

  18. Dynamin 2 regulates biphasic insulin secretion and plasma glucose homeostasis

    PubMed Central

    Fan, Fan; Ji, Chen; Wu, Yumei; Ferguson, Shawn M.; Tamarina, Natalia; Philipson, Louis H.; Lou, Xuelin

    2015-01-01

    Alterations in insulin granule exocytosis and endocytosis are paramount to pancreatic β cell dysfunction in diabetes mellitus. Here, using temporally controlled gene ablation specifically in β cells in mice, we identified an essential role of dynamin 2 GTPase in preserving normal biphasic insulin secretion and blood glucose homeostasis. Dynamin 2 deletion in β cells caused glucose intolerance and substantial reduction of the second phase of glucose-stimulated insulin secretion (GSIS); however, mutant β cells still maintained abundant insulin granules, with no signs of cell surface expansion. Compared with control β cells, real-time capacitance measurements demonstrated that exocytosis-endocytosis coupling was less efficient but not abolished; clathrin-mediated endocytosis (CME) was severely impaired at the step of membrane fission, which resulted in accumulation of clathrin-coated endocytic intermediates on the plasma membrane. Moreover, dynamin 2 ablation in β cells led to striking reorganization and enhancement of actin filaments, and insulin granule recruitment and mobilization were impaired at the later stage of GSIS. Together, our results demonstrate that dynamin 2 regulates insulin secretory capacity and dynamics in vivo through a mechanism depending on CME and F-actin remodeling. Moreover, this study indicates a potential pathophysiological link between endocytosis and diabetes mellitus. PMID:26413867

  19. Biphasic cell responses on laterally mobile films

    NASA Astrophysics Data System (ADS)

    Kourouklis, Andreas; Lerum, Ronald; Bermudez, Harry

    2013-03-01

    The engineering of polymer surfaces or matrices that are capable of controlling cell adhesion has been widely explored. In nearly all of these works, the polymer chains (and ligands) are chemically attached to the underlying substrate, and therefore these systems are inherently static. By contrast, cellular environments such as the extracellular matrix (ECM) are dynamic and remodeled by biochemical reactions and biophysical forces. Borrowing this concept from Nature, we created polymer films by an interfacial self-assembly process, whereby individual chains can exhibit lateral mobility (in-plane diffusive motion). NIH 3T3 fibroblasts seeded on such RGD-presenting polymer films show biphasic responses in spreading and adhesion strength to lateral mobility, with a minimal response for intermediate mobility values. Futhermore, preliminary immuno-staining experiments reveal that the total area of focal adhesions demonstrates a similar biphasic trend to the cellular-scale behaviors. In contrast, actin filaments or stress fibers appear to be unaffected by the substrate lateral mobility. These results show that lateral mobility is an important, although not fully explored aspect of mechano-sensing by cells, and can potentially give new perspectives on cell-ECM interactions. National Science Foundation

  20. Fourier-transform spectral interferometry for in situ group delay dispersion monitoring of thin film coating processes.

    PubMed

    Schlichting, Sebastian; Willemsen, Thomas; Ehlers, Henrik; Morgner, Uwe; Ristau, Detlev

    2016-10-03

    A fast Fourier-based measurement system to determine phase, group delay, and group delay dispersion during optical coating processes is proposed. The in situ method is based on a Michelson interferometer with a broad band light source and a very fast spectrometer. To our knowledge, group delay dispersion measurements directly on the moving substrates during a deposition process for complex interference coatings have been demonstrated for the first time. Especially for the very precise production of chirped mirrors it is advantageous to get information about the phase properties of the grown layer stack to react on errors and retrieve more information about the coating process.

  1. Biphasic microtiter method for campylobacter recovery and enumeration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We developed a biphasic method for recovery and enumeration of campylobacters. The biphasic system was composed of 96-well microtiter plates containing Campy-Line Agar (CLA) prepared 2X for all ingredients except for 1X agar (0.1 ml per well). Samples of pure Campylobacter spp. isolates, post-chi...

  2. Comparison between Quantitative Buffy Coat (QBC) and Giemsa-stained Thin Film (GTF) technique for blood protozoan infections in wild rats.

    PubMed

    Sahimin, N; Alias, S N; Woh, P Y; Edah, M A; Mohd Zain, S N

    2014-09-01

    The quantitative buffy coat (QBC) technique and conventional Giemsa thin blood smear was compared to determine the sensitivity and specificity of the technique in detecting blood parasitic infection of the rodent populations from four urban cities in Peninsular Malaysia. A total of 432 blood samples from four rat species (Rattus norvegicus, Rattus rattus diardii, Rattus exulans and Rattus argentiventer) were screened using both techniques and successfully detected two blood protozoan species (Trypanosoma lewisi and Plasmodium sp.) with Trypanosoma lewisi predominantly infecting the population. Results showed that Giemsa-stained thin film (GTF) was the better detection method on blood parasitemia (46.7%) compared to Quantitative Buffy Coat method (38.9%) with overall detection technique sensitivity and specificity at 83.2% and 74.8% respectively. The sensitivity in detection of Trypanosoma lewisi was 84.4% with value slightly lower for Plasmodium sp. infections at 76.6%. Statistical analysis proved that GTF technique was significantly more sensitive in the detection of blood protozoan infections in the rodent population compared to QBC (p<0.05).

  3. Effects of dip-coating speed and annealing temperature on structural, morphological and optical properties of sol-gel nano-structured TiO2 thin films

    NASA Astrophysics Data System (ADS)

    Touam, Tahar; Atoui, Mohamed; Hadjoub, Ilhem; Chelouche, Azeddine; Boudine, Boubekeur; Fischer, Alexis; Boudrioua, Azzedine; Doghmane, Abdellaziz

    2014-09-01

    We reported material characterization of the nano-structured TiO2 thin films prepared by the sol-gel dip-coating process on glass substrates. The dependence of the structural, morphological and optical properties of the synthesized films on the fabrication parameters such as withdrawal velocity and annealing temperature were investigated by the techniques of X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV-visible spectrophotometry. The results indicate that for the TiO2 films annealed at 500 °C there exhibits (1 0 1) XRD peak corresponding to the anatase phase of TiO2. The latter is consistent with the recorded Raman signal observed at 142 cm-1 (Eg mode) and 391 cm-1 (B1g mode), respectively. From the analyses made on the SEM micrographs and AFM images, it was revealed that the morphology and surface roughness of the thin films would depend on the withdrawal speed and the heat treatment temperature. The UV-visible spectroscopy analyses show that all the films were transparent in the visible region with an average transmittance of more than 70%. With an increase on the dip-coating speed from 1 cm/min to 3 cm/min, we observed a spectral red shift of the absorption edge from 3.76 eV to 3.71 eV, indicating a decrease in the bandgap energy (Eg) of the films.

  4. The use of magnetron sputtering for the deposition of thin titanium coatings on the surface of bioresorbable electrospun fibrous scaffolds for vascular tissue engineering: A pilot study

    NASA Astrophysics Data System (ADS)

    Bolbasov, E. N.; Antonova, L. V.; Stankevich, K. S.; Ashrafov, A.; Matveeva, V. G.; Velikanova, E. A.; Khodyrevskaya, Yu. I.; Kudryavtseva, Yu. A.; Anissimov, Y. G.; Tverdokhlebov, S. I.; Barbarash, L. S.

    2017-03-01

    The deposition of thin titanium coatings using magnetron spattering on the surface of bioresorbable fibrous scaffolds produced by electrospinning was investigated. Parameters that allow the surface modification without damaging the "macro" structure of scaffolds were determined. Physicochemical properties of the modified scaffolds were described using SEM, EDS, DSC, optical goniometry, and mechanical testing. It was shown that plasma treatment has a significant influence on the scaffolds' fiber surface relief. The modification process leads to a slight decrease of the scaffold mechanical performance mainly caused by polymer crystallization. Increasing the deposition time increases the amount of titanium on the surface. The biocompatibility of the modified scaffolds was studied using hybridoma of the endothelial cells of human umbilical vein and human lung carcinoma (EA.hy 926 cell line). Cell adhesion, viability, and secretion of interleukin-6 (IL6), interleukin-8 (IL8), and vascular endothelial growth factor (VEGF) were investigated. It was demonstrated that the deposition of thin titanium coatings on the fibrous scaffolds' surface enhances cell adhesion. Additionally, it was determined that modified scaffolds have proangiogenic activity.

  5. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    SciTech Connect

    K. Osseo-Asare; X. Zeng

    2002-01-01

    The objective of this research project is to develop an aqueous biphase extraction process for the treatment of fine coals. Aqueous biphase extraction is an advanced separation technology that relies on the ability of an aqueous system consisting of a water-soluble polymer and another component, e.g., another polymer, an inorganic salt, or a nonionic surfactant, to separate into two immiscible aqueous phases. The principle behind the partition of solid particles in aqueous biphase systems is the physicochemical interaction between the solid surface and the surrounding liquid solution. In order to remove sulfur and mineral matter from fine coal with aqueous biphasic extraction, it is necessary to know the partitioning behavior of coal, as well as the inorganic mineral components. Therefore, in this research emphasis was placed on the partitioning behavior of fine coal particles as well as model fine inorganic particles in aqueous biphase systems.

  6. Synthesis and characterization of ZnO:TiO{sub 2} nano composites thin films deposited on glass substrate by sol-gel spray coating technique

    SciTech Connect

    Sutanto, Heri Nurhasanah, Iis; Hidayanto, Eko; Wibowo, Singgih; Hadiyanto

    2015-12-29

    In this work, (ZnO){sub x}:(TiO{sub 2}){sub 1-x} nano composites thin films, with x = 1, 0.75, 0.5, 0.25, and 0, have been prepared by sol–gel spray coating technique onto glass substrate. Pure TiO{sub 2} and ZnO thin films were synthesized from titanium isopropoxide-based and zinc acetate-based precursor solutions, respectively, whereas the composite films were obtained from the mixture of these solutions at the specific % vol ratios. The properties and performance of nano composite ZnO, TiO{sub 2} and ZnO:TiO{sub 2} thin films at different composition have been investigated. Ultraviolet – Visible (UV-Vis) Spectrophotometer and Scanning Electron Microscopy (SEM) were employed in order to get morphology and transmittance of thin films. Testing the ability of photocatalytic activity of obtained films was conducted on photodegradation of methylene blue (MB) dye and organic pollutants of wastewater under a 30 watt UV light irradiation, then testing BOD, COD and TPC were conducted. Using the Tauc model, the band-gap energy decreased from 3.12 eV to 3.02 eV for the sample with x = 1 and 0, respectively. This decrease occured along with the replacement of percentage of ZnO by TiO{sub 2} on the films. This decrease also reduced the minimum energy that required for electron excitation. Obtained thin films had nanoscale roughness level with range 3.64 to 17.30 nm. The film with x= 0 has the biggest removal percentage on BOD, COD and TPC mesurements with percentage 54.82%, 62.73% and 99.88%, respectively.

  7. Synthesis and characterization of ZnO:TiO2 nano composites thin films deposited on glass substrate by sol-gel spray coating technique

    NASA Astrophysics Data System (ADS)

    Sutanto, Heri; Nurhasanah, Iis; Hidayanto, Eko; Wibowo, Singgih; Hadiyanto

    2015-12-01

    In this work, (ZnO)x:(TiO2)1-x nano composites thin films, with x = 1, 0.75, 0.5, 0.25, and 0, have been prepared by sol-gel spray coating technique onto glass substrate. Pure TiO2 and ZnO thin films were synthesized from titanium isopropoxide-based and zinc acetate-based precursor solutions, respectively, whereas the composite films were obtained from the mixture of these solutions at the specific % vol ratios. The properties and performance of nano composite ZnO, TiO2 and ZnO:TiO2 thin films at different composition have been investigated. Ultraviolet - Visible (UV-Vis) Spectrophotometer and Scanning Electron Microscopy (SEM) were employed in order to get morphology and transmittance of thin films. Testing the ability of photocatalytic activity of obtained films was conducted on photodegradation of methylene blue (MB) dye and organic pollutants of wastewater under a 30 watt UV light irradiation, then testing BOD, COD and TPC were conducted. Using the Tauc model, the band-gap energy decreased from 3.12 eV to 3.02 eV for the sample with x = 1 and 0, respectively. This decrease occured along with the replacement of percentage of ZnO by TiO2 on the films. This decrease also reduced the minimum energy that required for electron excitation. Obtained thin films had nanoscale roughness level with range 3.64 to 17.30 nm. The film with x= 0 has the biggest removal percentage on BOD, COD and TPC mesurements with percentage 54.82%, 62.73% and 99.88%, respectively.

  8. Osseointegration is improved by coating titanium implants with a nanostructured thin film with titanium carbide and titanium oxides clustered around graphitic carbon.

    PubMed

    Veronesi, Francesca; Giavaresi, Gianluca; Fini, Milena; Longo, Giovanni; Ioannidu, Caterina Alexandra; Scotto d'Abusco, Anna; Superti, Fabiana; Panzini, Gianluca; Misiano, Carlo; Palattella, Alberto; Selleri, Paolo; Di Girolamo, Nicola; Garbarino, Viola; Politi, Laura; Scandurra, Roberto

    2017-01-01

    Titanium implants coated with a 500nm nanostructured layer, deposited by the Ion Plating Plasma Assisted (IPPA) technology, composed of 60% graphitic carbon, 25% titanium oxides and 15% titanium carbide were implanted into rabbit femurs whilst into the controlateral femurs uncoated titanium implants were inserted as control. At four time points the animals were injected with calcein green, xylenol orange, oxytetracycline and alizarin. After 2, 4 and 8weeks femurs were removed and processed for histology and static and dynamic histomorphometry for undecalcified bone processing into methylmethacrylate, sectioned, thinned, polished and stained with Toluidine blue and Fast green. The overall bone-implant contacts rate (percentage of bone-implant contacts/weeks) of the TiC coated implant was 1.6 fold than that of the uncoated titanium implant. The histomorphometric analyses confirmed the histological evaluations. More precisely, higher Mineral Apposition Rate (MAR, μm/day) (p<0.005) and Bone Formation Rate (BFR, μm(2)/μm/day) (p<0.0005) as well as Bone Implant Contact (Bic) and Bone Ingrowth values (p<0.0005) were observed for the TiC coated implants compared to uncoated implants. In conclusion the hard nanostructured TiC layer protects the bulk titanium implant against the harsh conditions of biological tissues and in the same time, stimulating adhesion, proliferation and activity of osteoblasts, induces a better bone-implant contacts of the implant compared to the uncoated titanium implant.

  9. Degradation and Characterization of Resorbable Phosphate-Based Glass Thin-Film Coatings Applied by Radio-Frequency Magnetron Sputtering.

    PubMed

    Stuart, Bryan W; Gimeno-Fabra, Miquel; Segal, Joel; Ahmed, Ifty; Grant, David M

    2015-12-16

    Quinternary phosphate-based glasses of up to 2.67 μm, deposited by radio-frequency magnetron sputtering, were degraded in distilled water and phosphate-buffered saline (PBS) to investigate their degradation characteristics. Magnetron-sputtered coatings have been structurally compared to their compositionally equivalent melt-quenched bulk glass counterparts. The coatings were found to have structurally variable surfaces to melt-quenched glass such that the respective bridging oxygen to nonbridging oxygen bonds were 34.2% to 65.8% versus 20.5% to 79.5%, forming metaphosphate (PO3)(-) (Q(2)) versus less soluble (P2O7)(4-) (Q(1)) and (PO4)(3-) (Q(0)), respectively. This factor led to highly soluble coatings, exhibiting a t(1/2) degradation dependence in the first 2 h in distilled water, followed by a more characteristic linear profile because the subsequent layers were less soluble. Degradation was observed to preferentially occur, forming voids characteristic of pitting corrosion, which was confirmed by the use of a focused ion beam. Coating degradation in PBS precipitated a (PO3)(-) metaphosphate, an X-ray amorphous layer, which remained adherent to the substrate and seemingly formed a protective diffusion barrier, which inhibited further coating degradation. The implications are that while compositionally similar, sputter-deposited coatings and melt-quenched glasses are structurally dissimilar, most notably, with regard to the surface layer. This factor has been attributed to surface etching of the as-deposited coating layer during deposition and variation in the thermal history between the processes of magnetron sputtering and melt quenching.

  10. Proof of damage-free selective removal of thin dielectric coatings on silicon wafers by irradiation with femtosecond laser pulses

    SciTech Connect

    Rublack, Tino; Muchow, Markus; Schade, Martin; Leipner, Hartmut S.; Seifert, Gerhard

    2012-07-15

    The microstructural impact of selective femtosecond laser ablation of thin dielectric layers from monocrystalline silicon wafers was investigated. Various spots opened by 280 fs laser pulses at {lambda} = 1.03 {mu}m wavelength and 50 fs pulses at 800 nm, respectively, were analyzed in detail using Raman and transmission electron microscopy. The results show clearly that the thin dielectric films can be removed without any detectable modification of the Si crystal structure in the opened area. In contrast, in adjacent regions corresponding to laser fluence slightly below the breaking threshold, a thin layer of amorphous silicon with a maximum thickness of about 50 nm is found at the Si/SiO{sub 2} interface after laser irradiation. More than one pulse on the same position, however, causes structural modification of the silicon after thin film ablation in any case.

  11. Silicon micro venturi nozzles for cost-efficient spray coating of thin organic P3HT/PCBM layers

    NASA Astrophysics Data System (ADS)

    Betz, Michael A.; Büchele, Patric; Brünnler, Manfred; Deml, Sonja; Lechner, Alfred

    2017-01-01

    Improvements on spray coating are of particular interest to different fields of technology as it is a scalable deposition method and processing from solutions offer various application possibilities outside of typical facilities. When it comes to the deposition of expensive and film-forming media such as organic semiconductors, consumption and nozzle cleaning issues are of particular importance. We demonstrate the simple steps to design and fabricate micro venturi nozzles for economical spray coating with a consumption as low as 30-50 µl · min-1. For spray coating an active area of 25 cm2 a 2.45-4.01 fold coating efficiency is observed compared to a conventional airbrush nozzle set. The electrical characterization of first diodes sprayed with an active layer thickness of ~750 nm using a single micronozzle at a coating speed of 1.7 cm2 · min-1 reveals a good external quantum efficiency of 72.9% at 532 nm and a dark current of ~7.4 · 10-5 mA · cm-2, both measured at  -2 V. Furthermore, the high resistance of the micronozzles against solvents and most acids is provided through realization in a silicon wafer with silicon dioxide encapsulation, therefore allowing easy and effective cleaning.

  12. Advances in microreaction technology for portable fuel cell applications: Wall coating of thin catalytic films in microreactors

    NASA Astrophysics Data System (ADS)

    Bravo Bersano, Jaime Cristian

    This research has focused on the need to coat microreactor systems composed of channels in the micron size range of 100 to 1000 mum. The experimental procedures and learning are outlined in terms of slurry and surface preparation requirements which are detailed in the experimental section. This system is motivated and applied to micro methanol steam reformers. Thus, a detailed discussion on the driving motivation is given in the introduction. The low temperatures required for steam-reforming of methanol ˜ 493°K (220°C) make it possible to utilize the reformate as a feed to the fuel cell anode. The group of catalysts that shows the highest activity for methanol steam reforming (SR) at low temperature has composition of CuO/ZnO/Al 2O3, which is also the catalyst used for methanol synthesis. Steam reforming of methanol is a highly endothermic process. Conventional reactor configurations, such as a packed bed reactor, operate in a heat transfer limited mode for this reaction. Using catalyst in packed bed form for portable devices is also not convenient due to high pressure drop and possible channeling of gases in addition to poor heat transfer. A wall-coated catalyst represents a superior geometry since it provides lower pressure drop and ease of manufacturing. Due to their small size, microreactors are especially suited for endothermic reactions whose reactivity depends on the rate of heat input. A brief review on microreaction technology is given with a comprehensive survey for catalyst integration into microreactors for catalytic heterogeneous gas phase reactions. The strength of this research is the model that was developed to coat the interior of micron sized capillaries with coats of CuO/ZnO/Al2O 3 slurries as thick as 25 mum in the dry state. The details of the model are given in terms Taylor's theory and Rayleigh's theory. A model is presented that can predict the coat thickness based on experimental conditions The model combines Taylor's experimental work

  13. Mechanisms of LiCoO2 Cathode Degradation by Reaction with HF and Protection by Thin Oxide Coatings.

    PubMed

    Tebbe, Jonathon L; Holder, Aaron M; Musgrave, Charles B

    2015-11-04

    Reactions of HF with uncoated and Al and Zn oxide-coated surfaces of LiCoO2 cathodes were studied using density functional theory. Cathode degradation caused by reaction of HF with the hydroxylated (101̅4) LiCoO2 surface is dominated by formation of H2O and a LiF precipitate via a barrierless reaction that is exothermic by 1.53 eV. We present a detailed mechanism where HF reacts at the alumina coating to create a partially fluorinated alumina surface rather than forming AlF3 and H2O and thus alumina films reduce cathode degradation by scavenging HF and avoiding H2O formation. In contrast, we find that HF etches monolayer zinc oxide coatings, which thus fail to prevent capacity fading. However, thicker zinc oxide films mitigate capacity loss by reacting with HF to form a partially fluorinated zinc oxide surface. Metal oxide coatings that react with HF to form hydroxyl groups over H2O, like the alumina monolayer, will significantly reduce cathode degradation.

  14. Optical properties of nanostructured TiO2 thin films and their application as antireflection coatings on infrared detectors.

    PubMed

    Jayasinghe, R C; Perera, A G U; Zhu, H; Zhao, Y

    2012-10-15

    Oblique-angle deposited titanium dioxide (TiO(2)) nanorods have attracted much attention as good antireflection (AR) coating material due to their low n profile. Therefore, it is necessary to better understand the optical properties of these nanorods. TiO(2) nanorods grown on glass and Si substrates were characterized in the visible (0.4-0.8 μm) and infrared (2-12 μm) regions to extract their complex n profiles empirically. Application of these nanorods in multilayer AR coatings on infrared detectors is also discussed. Optimization of graded index profile of these AR coatings in the broad infrared region (2-12 μm) even at oblique angles of incidence is discussed. The effective coupling between the incoming light and multiple nanorod layers for reducing the reflection is obtained by optimizing the effect from Fabry-Perot oscillations. An optimized five-layer AR coating on GaN shows the reflectance less than 3.3% for normal incidence and 10.5% at 60° across the whole 2-8 μm spectral range.

  15. Thickness and structure change of titanium(IV) oxide thin films synthesized by the sol-gel spin coating method

    NASA Astrophysics Data System (ADS)

    Lewkowicz, Aneta; Synak, Anna; Grobelna, Beata; Bojarski, Piotr; Bogdanowicz, Robert; Karczewski, Jakub; Szczodrowski, Karol; Behrendt, Mirosław

    2014-08-01

    Titanium dioxide is a well-known material in nanotechnology, while it provides new opportunities due to its interesting properties, for example, as a semiconductor with a quite significant forbidden band gap energy of 3.2 eV. In this study, thin films of titanium dioxide (TiO2) were synthesized in amorphous and crystallographic systems using the sol-gel process. Atomic Force Microscopy (AFM), Raman spectroscopy and X-ray diffraction (XRD) techniques were applied to obtain structural characteristics of the prepared films. We estimated that TiO2 thin films crystallize in anatase phase between temperatures 380 °C and 700 °C, and into anatase-rutile phase at 650 °C, while rutile phase exists alone above 800 °C. The changes in porosity of materials in relation to temperature were calculated as well. The refractive index of titanium dioxide thin films from ellipsometric measurements is also provided.

  16. Studies on VO{sub x} thin films deposited over Si{sub 3}N{sub 4} coated Si substrates

    SciTech Connect

    Raj, P. Deepak; Sridharan, M.; Gupta, Sudha

    2015-06-24

    Vanadium oxide (VO{sub x}) thin films were deposited on to the silicon nitride (Si{sub 3}N{sub 4}) coated silicon (Si) substrate using reactive direct current magnetron sputtering at different substrate temperatures (T{sub s}). The deposited films were characterized for their structural, morphological, optical and electrical properties. The average grain size of the deposited films was in the range of 95 to 178 nm and the strain varied from 0.071 to 0.054 %. The optical bandgap values of the films were evaluated using UV-Vis spectroscopy and lies in the range of 2.46 to 3.88 eV. The temperature coefficient of resistance (TCR) for the film deposited at 125 °C was -1.23%/°C with the sheet resistivity of 2.7 Ω.cm.

  17. Photocatalytic antibacterial performance of glass fibers thin film coated with N-doped SnO2/TiO2.

    PubMed

    Kongsong, Peerawas; Sikong, Lek; Niyomwas, Sutham; Rachpech, Vishnu

    2014-01-01

    Both N-doped and undoped thin films of 3SnO2/TiO2 composite were prepared, by sol-gel and dip-coating methods, and then calcined at 600 °C for 2 hours. The films were characterized by FTIR, XRD, UV-Vis, SEM, and XPS, and their photocatalytic activities to degrade methylene blue in solution were determined, expecting these activities to correlate with the inactivation of bacteria, which was confirmed. The doped and undoped films were tested for activities against Gram-negative Escherichia coli (E. coli) and Salmonella typhi (S. typhi), and Gram-positive Staphylococcus aureus (S. aureus). The effects of doping on these composite films included reduced energy band gap, high crystallinity of anatase phase, and small crystallite size as well as increased photocatalytic activity and water disinfection efficiency.

  18. Photocatalytic Antibacterial Performance of Glass Fibers Thin Film Coated with N-Doped SnO2/TiO2

    PubMed Central

    Sikong, Lek; Niyomwas, Sutham; Rachpech, Vishnu

    2014-01-01

    Both N-doped and undoped thin films of 3SnO2/TiO2 composite were prepared, by sol-gel and dip-coating methods, and then calcined at 600°C for 2 hours. The films were characterized by FTIR, XRD, UV-Vis, SEM, and XPS, and their photocatalytic activities to degrade methylene blue in solution were determined, expecting these activities to correlate with the inactivation of bacteria, which was confirmed. The doped and undoped films were tested for activities against Gram-negative Escherichia coli (E. coli) and Salmonella typhi (S. typhi), and Gram-positive Staphylococcus aureus (S. aureus). The effects of doping on these composite films included reduced energy band gap, high crystallinity of anatase phase, and small crystallite size as well as increased photocatalytic activity and water disinfection efficiency. PMID:24693250

  19. Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO2 nanoparticles on a Si substrate

    PubMed Central

    Joost, Urmas; Šutka, Andris; Visnapuu, Meeri; Tamm, Aile; Lembinen, Meeri; Antsov, Mikk; Utt, Kathriin; Smits, Krisjanis; Nõmmiste, Ergo

    2017-01-01

    Colorimetric gas sensing is demonstrated by thin films based on ultrasmall TiO2 nanoparticles (NPs) on Si substrates. The NPs are bound into the film by p-toluenesulfonic acid (PTSA) and the film is made to absorb volatile organic compounds (VOCs). Since the color of the sensing element depends on the interference of reflected light from the surface of the film and from the film/silicon substrate interface, colorimetric detection is possible by the varying thickness of the NP-based film. Indeed, VOC absorption causes significant swelling of the film. Thus, the optical path length is increased, interference wavelengths are shifted and the refractive index of the film is decreased. This causes a change of color of the sensor element visible by the naked eye. The color response is rapid and changes reversibly within seconds of exposure. The sensing element is extremely simple and cheap, and can be fabricated by common coating processes. PMID:28243561

  20. Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO2 nanoparticles on a Si substrate.

    PubMed

    Joost, Urmas; Šutka, Andris; Visnapuu, Meeri; Tamm, Aile; Lembinen, Meeri; Antsov, Mikk; Utt, Kathriin; Smits, Krisjanis; Nõmmiste, Ergo; Kisand, Vambola

    2017-01-01

    Colorimetric gas sensing is demonstrated by thin films based on ultrasmall TiO2 nanoparticles (NPs) on Si substrates. The NPs are bound into the film by p-toluenesulfonic acid (PTSA) and the film is made to absorb volatile organic compounds (VOCs). Since the color of the sensing element depends on the interference of reflected light from the surface of the film and from the film/silicon substrate interface, colorimetric detection is possible by the varying thickness of the NP-based film. Indeed, VOC absorption causes significant swelling of the film. Thus, the optical path length is increased, interference wavelengths are shifted and the refractive index of the film is decreased. This causes a change of color of the sensor element visible by the naked eye. The color response is rapid and changes reversibly within seconds of exposure. The sensing element is extremely simple and cheap, and can be fabricated by common coating processes.

  1. Method and system using power modulation for maskless vapor deposition of spatially graded thin film and multilayer coatings with atomic-level precision and accuracy

    DOEpatents

    Montcalm, Claude; Folta, James Allen; Tan, Swie-In; Reiss, Ira

    2002-07-30

    A method and system for producing a film (preferably a thin film with highly uniform or highly accurate custom graded thickness) on a flat or graded substrate (such as concave or convex optics), by sweeping the substrate across a vapor deposition source operated with time-varying flux distribution. In preferred embodiments, the source is operated with time-varying power applied thereto during each sweep of the substrate to achieve the time-varying flux distribution as a function of time. A user selects a source flux modulation recipe for achieving a predetermined desired thickness profile of the deposited film. The method relies on precise modulation of the deposition flux to which a substrate is exposed to provide a desired coating thickness distribution.

  2. Photocatalytic degradation of glyphosate in water by N-doped SnO2/TiO2 thin-film-coated glass fibers.

    PubMed

    Kongsong, Peerawas; Sikong, Lek; Niyomwas, Sutham; Rachpech, Vishnu

    2014-01-01

    Photocatalytic degradation of glyphosate contaminated in water was investigated. The N-doped SnO2/TiO2 films were prepared via sol-gel method, and coated on glass fibers by dipping method. The effects of nitrogen doping on coating morphology, physical properties and glyphosate degradation rates were experimentally determined. Main variable was the concentration of nitrogen doping in range 0-40 mol%. Nitrogen doping results in shifting the absorption wavelengths and narrowing the band gap energy those lead to enhancement of photocatalytic performance. The near optimal 20N/SnO2/TiO2 composite thin film exhibited about two- and four-folds of glyphosate degradation rates compared to the undoped SnO2/TiO2 and TiO2 films when photocatalytic treatment were performed under UV and solar irradiations, respectively, due to its narrowest band gap energy (optical absorption wavelength shifting to visible light region) and smallest crystallite size influenced by N-doping.

  3. Performance of thin-ceramic-coated combustion chamber with gasoline and methanol as fuels in a two-stroke SI engine

    NASA Astrophysics Data System (ADS)

    Poola, Ramesh B.; Nagalingam, B.; Gopalakrishnan, K. V.

    The performance of a conventional, carbureted, two-stroke spark-ignition (SI) engine can be improved by providing moderate thermal insulation in the combustion chamber. This will help to improve the vaporization characteristics in particular at part load and medium loads with gasoline fuel and high-latent-heat fuels such as methanol. In the present investigation, the combustion chamber surface was coated with a 0.5-mm thickness of partially stabilized zirconia, and experiments were carried out in a single-cylinder, two-stroke SI engine with gasoline and methanol as fuels. Test results indicate that with gasoline as a fuel, the thin ceramic-coated combustion chamber improves the part load to medium load operation considerably, but it affects the performance at higher speeds and at higher loads to the extent of knock and loss of brake power by about 18%. However, with methanol as a fuel, the performance is better under most of the operating range and free from knock. Carbon monoxide (CO) emissions are significantly reduced, by about 3 to 4% volume, for both gasoline and methanol fuels due to relatively lean operation and more complete combustion. NO(x) emissions were not measured. The results show that moderate thermal insulation of the two-stroke SI engine's combustion chamber is better suited to methanol fuel with respect to thermal efficiency, CO emissions, and knock-free operation compared to gasoline fuel.

  4. Photocatalytic Treatment of Desalination Concentrate Using Optical Fibers Coated With Nanostructured Thin Films: Impact of Water Chemistry and Seasonal Climate Variations.

    PubMed

    Lin, Lu; Wang, Huiyao; Luo, Hongmei; Xu, Pei

    2016-05-01

    Treatment of desalination concentrate can reduce concentrate volume for disposal, increase water recovery and convert waste to resource. However, concentrate treatment is costly and energy intensive due to high concentrations of salt and recalcitrant organic matter in concentrate. Photocatalytic oxidation provides a novel energy neutral technology for concentrate treatment by degrading organic contaminants. Polymer-assisted hydrothermal deposition method was used to synthesize innovative pure and Fe-doped TiO2 mixed-phase nanocomposite thin films on side-glowing optical fibers (SOFs). The properties of the photocatalysts-coated SOF were characterized by surface morphology, nanostructure, crystallite size and phase and zeta potential. Photodegradation efficiency and durability of the photocatalysts treating different types of desalination concentrate was studied under natural sunlight. Synthetic solutions and reverse osmosis (RO) concentrates from brackish water and municipal wastewater desalination facilities were tested to elucidate the impact of water chemistry, operating conditions and seasonal climate variations (solar irradiation intensity and temperature) on photocatalytic efficiency. High ionic strength and divalent electrolyte ions in RO concentrate accelerated photocatalytic process, whereas the presence of carbonate species and organic matter hindered photodegradation. Outdoor testing of immobilized continuous-flow photoreactors suggested that the catalyst-coated SOFs can utilize a wide spectrum of natural sunlight and achieved durable photocatalytic performance.

  5. Direct Observation on Spin-Coating Process of PS- b -P2VP Thin Films

    SciTech Connect

    Ogawa, Hiroki; Takenaka, Mikihito; Miyazaki, Tsukasa; Fujiwara, Akihiko; Lee, Byeongdu; Shimokita, Keisuke; Nishibori, Eiji; Takata, Masaki

    2016-05-10

    We studied the structural development of symmetric poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) block copolymers during spin-coating using in situ grazing incidence small angle X-ray scattering (GISAXS) measurements. During the spin-coating process, after the formation of the micelles in dilute solution, the selective solvent induced two kinds of the morphological transition. Firstly, the disordered spherical micelles were transformed into a BCC lattice of spheres of which the (110) plane was oriented perpendicularly to the substrate surface. Secondly, further evaporation induced a transition from spheres on the BCC lattice into cylindrical structures. The orientation of the cylinders perpendicular to the substrate surface was induced by solvent convection perpendicular to the substrate, which occurs during rapid solvent evaporation. After this transition, vitrification of PS and P2VP prevented any further transition from cylinders to the more thermodynamically stable lamellar structures, as are generally observed as the bulk equilibrium state.

  6. Novel Measurements of Aerosol Particle Interfaces Using Biphasic Microfluidics

    NASA Astrophysics Data System (ADS)

    Metcalf, A. R.; Dutcher, C. S.

    2014-12-01

    Secondary organic aerosol (SOA) particles are nearly ubiquitous in the atmosphere and yet there remains large uncertainties in their formation processes and ambient properties. These particles are complex microenvironments, which can contain multiple interfaces due to internal aqueous-organic phase partitioning and to the external liquid-vapor surface. These aerosol interfaces can profoundly affect the fate of condensable organic compounds emitted into the atmosphere by altering the way in which organic vapors interact with the ambient aerosol. Aerosol interfaces affect particle internal structure, species uptake, equilibrium partitioning, activation to cloud condensation or ice nuclei, and optical properties. For example, organic thin films can shield the core of the aerosol from the ambient environment, which may disrupt equilibrium partitioning and mass transfer. To improve our ability to accurately predict the fate of SOA in the atmosphere, we must improve our knowledge of aerosol interfaces and their interactions with the ambient environment. Few technologies exist to accurately probe aerosol interfaces at atmospherically-relevant conditions. In this talk, a novel method using biphasic microscale flows will be introduced for generating, trapping, and perturbing complex interfaces at atmospherically relevant conditions. These microfluidic experiments utilize high-speed imaging to monitor interfacial phenomena at the microscale and are performed with phase contrast and fluorescence microscopy on a temperature-controlled inverted microscope stage. From these experiments, interfacial thermodynamic properties such as surface tension, rheological properties such as interfacial moduli, and kinetic properties such as mass transfer coefficients can be measured or inferred. Chemical compositions of the liquid phases studied here span a range of viscosities and include electrolyte and water soluble organic acid species often observed in the atmosphere, such as mixtures

  7. Vacuum arc plasma deposition of thin titanium dioxide films on silicone elastomer as a functional coating for medical applications.

    PubMed

    Boudot, Cécile; Kühn, Marvin; Kühn-Kauffeldt, Marina; Schein, Jochen

    2017-05-01

    Silicone elastomer is a promising material for medical applications and is widely used for implants with blood and tissue contact. However, its strong hydrophobicity limits adhesion of tissue cells to silicone surfaces, which can impair the healing process. To improve the biological properties of silicone, a triggerless pulsed vacuum cathodic arc plasma deposition technique was applied to deposit titanium dioxide (TiO2) films onto the surface. Scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and contact angle measurements were used for coating characterization. Deposited films were about 150nm thick and exhibited good adhesion to the underlying silicone substrate. Surface wettability and roughness both increased after deposition of the TiO2 layer. In addition, cell-biological investigations demonstrated that the in-vitro cytocompatibility of TiO2-coated samples was greatly improved without impacting silicone's nontoxicity. For validation of use in medical devices, further investigations were conducted and demonstrated stability of surface properties in an aqueous environment for a period of 68days and the coating's resistance to several sterilization methods.

  8. Water-Dispersible Silica-Coated Upconverting Liposomes: Can a Thin Silica Layer Protect TTA-UC against Oxygen Quenching?

    PubMed Central

    2017-01-01

    Light upconversion by triplet–triplet annihilation (TTA-UC) in nanoparticles has received considerable attention for bioimaging and light activation of prodrugs. However, the mechanism of TTA-UC is inherently sensitive for quenching by molecular oxygen. A potential oxygen protection strategy is the coating of TTA-UC nanoparticles with a layer of oxygen-impermeable material. In this work, we explore if (organo)silica can fulfill this protecting role. Three synthesis routes are described for preparing water-dispersible (organo)silica-coated red-to-blue upconverting liposomes. Their upconversion properties are investigated in solution and in A549 lung carcinoma cells. Although it was found that the silica offered no protection from oxygen in solution and after uptake in A549 cancer cells, upon drying of the silica-coated liposome dispersion in an excess of (organo)silica precursor, interesting liposome–silica nanocomposite materials were obtained that were capable of generating blue light upon red light excitation in air. PMID:28317022

  9. Effect of the silanization conditions on chromatographic behavior of an open-tubular capillary column coated with a modified silica-gel thin layer.

    PubMed

    Nakano, Yusuke; Kitagawa, Shinya; Miyabe, Kanji; Tsuda, Takao

    2005-10-01

    The performance of an open-tubular capillary column coated with a modified silica-gel thin layer was investigated, particularly concerning the effect of the silanization process on it. Although the increase in the octadecyltriethoxysilane (ODTES) concentration in the silanization process could enhance the retention factor of naphthalene, its theoretical plate number was significantly reduced (ODTES, 5 to 50%; k, 0.2 to 4.3; N, 79600 to 2600 m(-1)). Namely, the increase in the retention factor was accompanied by a decrease in the theoretical plate number. A similar phenomenon was also observed when octadecyldimethylchlorosilane (ODCS) was used as the silanization regent. However, increases in both the retention factor and the theoretical plate number could be achieved (sample, naphthalene; k, 0.05 to 0.09; N, 149000 to 220000 m(-1)) by a NaOH treatment to the fabricated thin porous silica-gel layer before silanization with ODCS. The electrochromatographic separation of proteins and peptides by using the NaOH-treated column could obtain more peaks than electrophoretic separation.

  10. Studies on visible light photocatalytic and antibacterial activities of nanostructured cobalt doped ZnO thin films prepared by sol-gel spin coating method

    NASA Astrophysics Data System (ADS)

    Poongodi, G.; Anandan, P.; Kumar, R. Mohan; Jayavel, R.

    2015-09-01

    Nanostructured cobalt doped ZnO thin films were deposited on glass substrate by sol-gel spin coating technique and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and UV-Vis spectroscopy. The XRD results showed that the thin films were well crystalline with hexagonal wurtzite structure. The results of EDAX and XPS revealed that Co was doped into ZnO structure. FESEM images revealed that the films possess granular morphology without any crack and confirm that Co doping decreases the grain size. UV-Vis transmission spectra show that the substitution of Co in ZnO leads to band gap narrowing. The Co doped ZnO films were found to exhibit improved photocatalytic activity for the degradation of methylene blue dye under visible light in comparison with the undoped ZnO film. The decrease in grain size and extending light absorption towards the visible region by Co doping in ZnO film contribute equally to the improved photocatalytic activity. The bactericidal efficiency of Co doped ZnO films were investigated against a Gram negative (Escherichia coli) and a Gram positive (Staphylococcus aureus) bacteria. The optical density (OD) measurement showed better bactericidal activity at higher level of Co doping in ZnO.

  11. Studies on visible light photocatalytic and antibacterial activities of nanostructured cobalt doped ZnO thin films prepared by sol-gel spin coating method.

    PubMed

    Poongodi, G; Anandan, P; Kumar, R Mohan; Jayavel, R

    2015-09-05

    Nanostructured cobalt doped ZnO thin films were deposited on glass substrate by sol-gel spin coating technique and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and UV-Vis spectroscopy. The XRD results showed that the thin films were well crystalline with hexagonal wurtzite structure. The results of EDAX and XPS revealed that Co was doped into ZnO structure. FESEM images revealed that the films possess granular morphology without any crack and confirm that Co doping decreases the grain size. UV-Vis transmission spectra show that the substitution of Co in ZnO leads to band gap narrowing. The Co doped ZnO films were found to exhibit improved photocatalytic activity for the degradation of methylene blue dye under visible light in comparison with the undoped ZnO film. The decrease in grain size and extending light absorption towards the visible region by Co doping in ZnO film contribute equally to the improved photocatalytic activity. The bactericidal efficiency of Co doped ZnO films were investigated against a Gram negative (Escherichia coli) and a Gram positive (Staphylococcus aureus) bacteria. The optical density (OD) measurement showed better bactericidal activity at higher level of Co doping in ZnO.

  12. Optical properties of double layer thin films zinc oxide doping aluminum (ZnO/Al) were deposited on glass substrates by sol gel method spray coating technique

    NASA Astrophysics Data System (ADS)

    Permatasari, Anes; Sutanto, Heri; Marito Siagian, Sinta

    2017-01-01

    Thin films of double layer of ZnO/Al has succeeded in deposition on a glass substrate using sol-gel method and spray coating techniques. Variations of doping Al as much as 2%, 4%, 6% and 8%. ZnO precursor synthesized using zinc acetate dehydrate (Zn(COOCH3)2.2H2O), isopropanol ((CH3)2CHOH) and monoethanolamine (MEA) were stirred using a magnetic stirrer for 45 minutes. ZnO precursor get homogeneous and then added of aluminum nitrate nonahydrate predetermined doping concentration and stirred again for 15 minutes. Deposition solution is done by the spray on a glass substrate and then heated at a temperature of 450°C. A layer of ZnO/Al deposited over the ZnO to produce a thin layer of a double layer. Optical properties layer of ZnO/Al characterized using UV-Vis spectrophotometer. Based on data from UV-Vis absorbance was determined the value of the energy band gap. Pure and dopped layers has different energy due the Al dopping. For pure ZnO layer has energy band gap of 3.347 eV and decreased to 3.09 eV for ZnO layer with Al dopant.

  13. Effect of zinc addition and vacuum annealing time on the properties of spin-coated low-cost transparent conducting 1 at% Ga-ZnO thin films.

    PubMed

    Srivastava, Amit Kumar; Kumar, Jitendra

    2013-12-01

    Pure and 1 at% gallium (Ga)-doped zinc oxide (ZnO) thin films have been prepared with a low-cost spin coating technique on quartz substrates and annealed at 500 °C in vacuum ∼10(-3) mbar to create anion vacancies and generate charge carriers for photovoltaic application. Also, 0.5-1.5 at% extra zinc species were added in the precursor sol to investigate changes in film growth, morphology, optical absorption, electrical properties and photoluminescence. It is shown that 1 at% Ga-ZnO thin films with 0.5 at% extra zinc content after vacuum annealing for 60 min correspond to wurtzite-type hexagonal structure with (0001) preferred orientation, electrical resistivity of ∼9 × 10(-3) Ω cm and optical transparency of ∼65-90% in the visible range. Evidence has been advanced for the presence of defect levels within bandgap such as zinc vacancy (VZn), zinc interstitial (Zni), oxygen vacancy (Vo) and oxygen interstitial (Oi). Further, variation in ZnO optical bandgap occurring with Ga doping and insertion of additional zinc species has been explained by invoking two competing phenomena, namely bandgap widening and renormalization, usually observed in semiconductors with increasing carrier concentration.

  14. Effect of zinc addition and vacuum annealing time on the properties of spin-coated low-cost transparent conducting 1 at% Ga–ZnO thin films

    PubMed Central

    Srivastava, Amit Kumar; Kumar, Jitendra

    2013-01-01

    Pure and 1 at% gallium (Ga)-doped zinc oxide (ZnO) thin films have been prepared with a low-cost spin coating technique on quartz substrates and annealed at 500 °C in vacuum ∼10−3 mbar to create anion vacancies and generate charge carriers for photovoltaic application. Also, 0.5–1.5 at% extra zinc species were added in the precursor sol to investigate changes in film growth, morphology, optical absorption, electrical properties and photoluminescence. It is shown that 1 at% Ga–ZnO thin films with 0.5 at% extra zinc content after vacuum annealing for 60 min correspond to wurtzite-type hexagonal structure with (0001) preferred orientation, electrical resistivity of ∼9 × 10−3 Ω cm and optical transparency of ∼65–90% in the visible range. Evidence has been advanced for the presence of defect levels within bandgap such as zinc vacancy (VZn), zinc interstitial (Zni), oxygen vacancy (Vo) and oxygen interstitial (Oi). Further, variation in ZnO optical bandgap occurring with Ga doping and insertion of additional zinc species has been explained by invoking two competing phenomena, namely bandgap widening and renormalization, usually observed in semiconductors with increasing carrier concentration. PMID:27877622

  15. Effect of zinc addition and vacuum annealing time on the properties of spin-coated low-cost transparent conducting 1 at% Ga-ZnO thin films

    NASA Astrophysics Data System (ADS)

    Srivastava, Amit Kumar; Kumar, Jitendra

    2013-12-01

    Pure and 1 at% gallium (Ga)-doped zinc oxide (ZnO) thin films have been prepared with a low-cost spin coating technique on quartz substrates and annealed at 500 °C in vacuum ˜10-3 mbar to create anion vacancies and generate charge carriers for photovoltaic application. Also, 0.5-1.5 at% extra zinc species were added in the precursor sol to investigate changes in film growth, morphology, optical absorption, electrical properties and photoluminescence. It is shown that 1 at% Ga-ZnO thin films with 0.5 at% extra zinc content after vacuum annealing for 60 min correspond to wurtzite-type hexagonal structure with (0001) preferred orientation, electrical resistivity of ˜9 × 10-3 Ω cm and optical transparency of ˜65-90% in the visible range. Evidence has been advanced for the presence of defect levels within bandgap such as zinc vacancy (VZn), zinc interstitial (Zni), oxygen vacancy (Vo) and oxygen interstitial (Oi). Further, variation in ZnO optical bandgap occurring with Ga doping and insertion of additional zinc species has been explained by invoking two competing phenomena, namely bandgap widening and renormalization, usually observed in semiconductors with increasing carrier concentration.

  16. Vorticity banding in biphasic polymer blends.

    PubMed

    Caserta, Sergio; Guido, Stefano

    2012-11-27

    Pattern formation under the action of flow is a subject of considerable scientific interest with applications going from microfluidics to granular materials. Here, we present a systematic investigation of shear-induced banding in confined biphasic liquid-liquid systems, i.e., formation of alternating regions of high and low volume fraction of droplets in a continuous phase (shear bands). This phenomenon is investigated in immiscible polymer blends sheared in a sliding parallel plate flow cell. Starting from a spatially uniform distribution of droplets, the formation of bands aligned along the flow direction is observed, eventually leading to an almost complete separation between droplet-rich and continuous phase regions. The initial band size is related to the gap dimension; the merging of bands and consequent spacing reduction has also been observed for long times. Shear banding is only observed when the viscosity of the dispersed phase is lower as compared to the continuous phase and in a limited range of the applied shear rate. Rheological measurements show that band formation is associated with a viscosity decrease with respect to the homogeneous case, thus implying that system microstructure is somehow evolving toward reduced viscous dissipation under flow.

  17. Growth of thin films of dicyanovinylanisole on quartz and teflon-coated quartz by physical vapor transport

    NASA Technical Reports Server (NTRS)

    Pearson, Earl F.

    1994-01-01

    Organic compounds offer the possibility of molecular engineering in order to optimize the nonlinearity and minimize damage due to the high-power lasers used in nonlinear optical devices. Recently dicyanovinylanisole (DIVA), ((2-methoxyphenyl) methylenepropanedinitrile) has been shown to have a second order nonlinearity 40 times that of alpha-quartz. Debe et. al. have shown that a high degree of orientational order exists for thin films of phthalocyanine grown by physical vapor transport in microgravity. The microgravity environment eliminates convective flow and was critical to the formation of highly ordered dense continuous films in these samples. This work seeks to discover the parameters necessary for the production of thin continuous films of high optical quality in Earth gravity. These parameters must be known before the experiment can be planned for growing DIVA in a microgravity environment. The microgravity grown films are expected to be denser and of better optical quality than the unit gravity films as was observed in the phthalocyanine films.

  18. Bio-mimetic scaling of mechanical behavior of thin films, coatings, and surfaces by Laser Interference Metallurgy

    SciTech Connect

    Daniel, Claus; Balk, Thomas John; Wobben, Thomas; M�cklich, Frank

    2005-01-01

    Biological solutions to enhance strength and stability often use hierarchical composite structures. The effect is not based on large chemical variations, but instead is realized by structural composites with long-range order. Laser Interference Metallurgy is a newly developed technique that utilizes this biological approach to optimize the mechanical properties of surfaces and thin films. The possibility of scaling mechanical properties is quantitatively analyzed and compared with the biological approach.

  19. Ion-exchange voltammetry with nafion/poly(sodium 4-styrenesulfonate) mixed coatings on mercury film electrodes: characterization studies and application to the determination of trace metals.

    PubMed

    Rocha, Luciana S; Pinheiro, José Paulo; Carapuça, Helena M

    2006-09-12

    This work aimed to produce improved polymer coatings for the modification of thin mercury film electrodes (TMFEs). The goal is to obtain sensitive, reproducible, mechanically stable and antifouling devices suitable for the determination of trace metal cations in complex media. Therefore, novel mixed coatings of two sulfonated cation-exchange polymers of dissimilar characteristics-Nafion (NA) and poly(sodium 4-styrenesulfonate) (PSS)-were produced by solvent evaporation onto glassy carbon electrodes. The effect of the mass ratio (NA:PSS) on the film morphology was studied by scanning electron microscopy, revealing the formation of biphasic polymer systems, where PSS bead-shaped clusters appeared randomly dispersed into a uniform and compact NA environment. The permselectivity/ion-exchange features of the mixed films onto glassy carbon were evaluated using cathecol, urate, and dopamine. To allow trace metal analysis, thin mercury films were plated through the NA/PSS coatings, being the reproducibility and ion-exchange features of the mixed coatings-TMFE evaluated using lead ions. The best NA/PSS coating was found for the mass ratio of 5.3. Analytical performance of the NA/PSS-TMFE yielded a detection limit of 5.5 nM (3sigma), and the application of this modified electrode to an untreated polluted estuarine water sample produced significant improvements in the quality of the signal compared with that for a bare TMFE.

  20. The structure and composition of chromate conversion coatings formed on aluminum-copper alloy AA2024-T3 and thin film analogs of constituent intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Vasquez, Marvin Jaime

    2002-01-01

    A comprehensive suite of spectroscopy have been used to study the composition and structure of Chromate Conversion Coatings (CCC) formed on Aluminum Copper (Al-Cu) alloy AA2024-T3 and constituent Intermetallic Compounds (IMCs). Based on previous work the CCC formed over the IMCs is expected to be thinner and therefore different in structure and composition than the CCC formed on the matrix. The formation of the CCC over the different IMCs is expected to be dependent on the chemistry and the interaction of the IMCs with accelerators such as ferricyanide. Surface chemical and structural data determined by X-ray Photoelectron Spectroscopy (XPS), Synchrotron Infrared Microspectroscopy, X-ray Absorption Near Edge Spectroscopy (XANES), Extended X-ray Absorption Fine Structure (EXAFS), Secondary Ion Mass Spectrometry (SIMS), and Secondary Electron Microscopy/Energy Dispersive Analysis of X-rays (SEM/EDAX) have been developed to refine an existing model for the CCC formed on the AA2024-T3 surface, an Al-Cu aircraft alloy, by considering the composition and structure of the CCC formed on constituent intermetallic compounds (IMCs). The limited corrosion behavior of AA2024-T3 aluminum alloy is generally attributed to the presence of a variety of constituent IMC. These IMC particles are of the order of 1--20 mum which makes their direct analysis exceedingly difficult and has lead to a limited understanding of their surface chemical properties relative to CCC formation. To overcome this limitation, it was necessary to develop for the first time large area samples composed of compositionally homogenous thin films of the various IMCs found on the AA2024-T3 surface, which were galvanically attached to thin films of Al-4.2wt%Cu (representative of the AA2024-T3 matrix). This was performed in a two-step process: Disks of IMC compositions were formed by Reactive Arc Melting (RAM), followed by ultra-fast laser ablation of the RAM IMCs resulting in the formation of homogenous thin films

  1. Photocatalytic Functional Coating of TiO2 Thin Film Deposited by Cyclic Plasma Chemical Vapor Deposition at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Kwon, Jung-Dae; Rha, Jong-Joo; Nam, Kee-Seok; Park, Jin-Seong

    2011-08-01

    Photocatalytic TiO2 thin films were prepared with titanium tetraisopropoxide (TTIP) using cyclic plasma chemical vapor deposition (CPCVD) at atmospheric pressure. The CPCVD TiO2 films contain carbon-free impurities up to 100 °C and polycrystalline anatase phases up to 200 °C, due to the radicals and ion-bombardments. The CPCVD TiO2 films have high transparency in the visible wavelength region and absorb wavelengths below 400 nm (>3.2 eV). The photocatalytic effects of the CPCVD TiO2 and commercial sprayed TiO2 films were measured by decomposing methylene blue (MB) solution under UV irradiation. The smooth CPCVD TiO2 films showed a relatively lower photocatalytic efficiency, but superior catalyst-recycling efficiency, due to their high adhesion strength on the substrates. This CPCVD technique may provide the means to produce photocatalytic thin films with low cost and high efficiency, which would be a reasonable candidate for practical photocatalytic applications, because of the reliability and stability of their photocatalytic efficiency in a practical environment.

  2. Influence of Biphasic Stimulation on Olfactory Ensheathing Cells for Neuroprosthetic Devices

    PubMed Central

    Hassarati, Rachelle T.; Foster, L. John R.; Green, Rylie A.

    2016-01-01

    The recent success of olfactory ensheathing cell (OEC) assisted regeneration of injured spinal cord has seen a rising interest in the use of these cells in tissue-engineered systems. Previously shown to support neural cell growth through glial scar tissue, OECs have the potential to assist neural network formation in living electrode systems to produce superior neuroprosthetic electrode surfaces. The following study sought to understand the influence of biphasic electrical stimulation (ES), inherent to bionic devices, on cell survival and function, with respect to conventional metallic and developmental conductive hydrogel (CH) coated electrodes. The CH utilized in this study was a biosynthetic hydrogel consisting of methacrylated poly(vinyl-alcohol) (PVA), heparin and gelatin through which poly(3,4-ethylenedioxythiophene) (PEDOT) was electropolymerised. OECs cultured on Pt and CH surfaces were subjected to biphasic ES. Image-based cytometry yielded little significant difference between the viability and cell cycle of OECs cultured on the stimulated and passive samples. The significantly lower voltages measured across the CH electrodes (147 ± 3 mV) compared to the Pt (317 ± 5 mV), had shown to influence a higher percentage of viable cells on CH (91–93%) compared to Pt (78–81%). To determine the functionality of these cells following electrical stimulation, OECs co-cultured with PC12 cells were found to support neural cell differentiation (an indirect measure of neurotrophic factor production) following ES. PMID:27757072

  3. Assessment of balanced biphasic defibrillation waveforms in transthoracic atrial cardioversion.

    PubMed

    Krasteva, V; Trendafilova, E; Cansell, A; Daskalov, I

    2001-01-01

    Various electrical pulses have been used for defibrillation. The monophasic damped sinusoid waveform, initiated in 60 s, was adopted in virtually all defibrillators. Biphasic pulses were introduced recently, achieving success with less energy. A biphasic exponential waveform was modelled with 4 ms duration per phase with a balanced 3:1 ratio of the first to second phase peak voltages and implemented in a defibrillator. A version obtained by chopping the pulses with a 5 kHz frequency was also used. It was hypothesized that the modelled transmembrane voltage decay time is a parameter that could be associated with successful defibrillation. The results of cardioversion for two groups of patients with the 'classic' monophasic waveform and with the biphasic pulses were compared. The mean efficient energy with the damped sinusoid was 205 +/- 85 J, versus 88 +/- 43 J with the biphasic pulses, yielding a ratio of 2.32 (1.92 to 3.2 for fibrillation and flutter, respectively). An acceptable agreement between model data and clinical results was found. The transmembrane voltage decay time ratios for monophasic versus biphasic pulses was in the approximate range of 2.5 to 3.5.

  4. Biphasic catalysis in water/carbon dioxide micellar systems

    DOEpatents

    Jacobson, Gunilla B.; Tumas, William; Johnston, Keith P.

    2002-01-01

    A process is provided for catalyzing an organic reaction to form a reaction product by placing reactants and a catalyst for the organic reaction, the catalyst of a metal complex and at least one ligand soluble within one of the phases of said aqueous biphasic system, within an aqueous biphasic system including a water phase, a dense phase fluid, and a surfactant adapted for forming an emulsion or microemulsion within the aqueous biphasic system, the reactants soluble within one of the phases of the aqueous biphasic system and convertible in the presence of the catalyst to a product having low solubility in the phase in which the catalyst is soluble; and, maintaining the aqueous biphasic system under pressures, at temperatures, and for a period of time sufficient for the organic reaction to occur and form the reaction product and to maintain sufficient density on the dense phase fluid, the reaction product characterized as having low solubility in the phase in which the catalyst is soluble.

  5. Biphasic nanofibrous constructs with seeded cell layers for osteochondral repair.

    PubMed

    Jin, Guang-Zhen; Kim, Jung-Ju; Park, Jeong-Hui; Seo, Seog-Jin; Kim, Joong-Hyun; Lee, Eun-Jung; Kim, Hae-Won

    2014-11-01

    Biphasic scaffolds have gained increasing attention for the regeneration of osteochondral interfacial tissue because they are expected to effectively define the interfacial structure of tissue that comprises stratified cartilage with a degree of calcification. Here, we propose a biphasic nanofiber construct made of poly(lactide-co-caprolactone) (PLCL) and its mineralized form (mPLCL) populated with cells. Primary rat articular chondrocytes (ACs) and bone marrow-derived mesenchymal stem cells (MSCs) were cultured on the layers of bare PLCL and mPLCL nanofibers, respectively, for 7 days, and the biphasic cell-nanofiber construct was investigated at 4 weeks after implantation into nude mice. Before implantation, the ACs and MSCs grown on each layer of PLCL and mPLCL nanofibers exhibited phenotypes typical of chondrocytes and osteoblasts, respectively, under proper culture conditions, as analyzed by electron microscopy, histological staining, cell growth kinetics, and real-time polymerase chain reaction. The biphasic constructs also showed the development of a possible formation of cartilage and bone tissue in vivo. Results demonstrated that the cell-laden biphasic nanofiber constructs may be useful for the repair of osteochondral interfacial tissue structure.

  6. Confocal Raman microspectrometry: a vectorial electromagnetic treatment of the light focused and collected through a planar interface and its application to the study of a thin coating.

    PubMed

    Sourisseau, C; Maraval, P

    2003-11-01

    In-depth confocal Raman microspectrometry (CRM) studies through a planar interface between materials of mismatched refraction indices are known to be affected by a decrease of both the collected Raman intensity and the axial resolution as a function of the penetration depth. Following a previous model, which takes the refraction, diffraction, and spherical aberration effects into account when focusing a Gaussian incident laser beam with a high numerical aperture objective lens, a complete vectorial treatment of these phenomena is considered. It is demonstrated that off-axis refraction effects cannot be neglected and that the dimension of the confocal pinhole aperture plays a crucial role on the effective focal plane position and on the collection efficiency. We thus propose a more rigorous and complete approach to the problem, and we find a very good agreement between experimental and theoretical Raman intensity variations for a thick polyethylene sample as a function of the penetration depth. As compared with calculations where only refraction was considered, we confirm that the lengthening of the focus even for a large penetration depth is significantly reduced upon diffraction effects. As an illustrative example, the theoretical Raman responses for a thin coating of approximately 20 microns on a polymer substrate were investigated and compared to experimental results already published. Even though the interfacial region is spread over approximately 5-6 microns when using a 100x objective and a confocal pinhole of 200 microns diameter, it is definitively concluded that the apparent axial resolution is not drastically deteriorated with increasing depth and that the coating thickness may be directly estimated with a precision of approximately 1.0 micron (5%).

  7. Biphasic nanoparticles made by electrified jetting

    NASA Astrophysics Data System (ADS)

    Lahann, Joerg

    2005-03-01

    Nano-colloids have recently attracted intense attention due to unique properties that are distinctly different from bulk solid-state materials; including unique magnetic, electronic, optical, chemical, and biological characteristics. The vision that these nano-objects could essentially act as functional components in novel device generations, which ``magically'' assemble following a master blueprint void any human manipulation, has resulted in a new ``gold rush'' in materials science. These concepts have results in the synthesis of a multitude of nano-objects, such as nano-wires, nano-rods, nano-disks, or nano-prisms.^ Recently, nano-particles with anisotropic materials distributions (biphasic nano-particles) moved in the focus of research. Our approach differs fundamentally from the above-mentioned methods in that it takes advantage of electrified polymer jets to create anisotropic materials distributions in nano-objects. jetting is a process to generate liquid jets by use of electrostatic forces. It is well-known that high electrical potentials (typically several thousand volts) applied between the jetting liquids that are fed through a capillary and a collecting substrate will induce jetting of a charged liquid. The differences in the final morphologies from similar processes are mainly determined by the properties of the jetting liquids and the process parameters. transmission electron microscopy, scanning electron microscopy, and scanning laser confocal microscopy, we demonstrate the applicability of the process to control size, shape, and materials distribution at the nanoscale. The resulting anisotropic nanoparticles may have potential applications for targeted drug delivery or as electro-rehological fluids. a) F. M. Van der Kooij, K. Kassapidou and H. N. W. Lekkerkerker, Liquid crystal phase transitions in suspensions of polydisperse plate-like particles, Nature 406, 868 (2000); b) C. A. Mirkin, R. L. Letsinger, R. C. Mucic and J. J. Storhoff, A DNA

  8. Cross-linked chitosan thin film coated onto glass plate as an effective adsorbent for adsorption of reactive orange 16.

    PubMed

    Jawad, Ali H; Azharul Islam, Md; Hameed, B H

    2017-02-01

    Fabrication of an immobilized cross-linked chitosan-epichlorohydrine thin film (CLCETF) onto glass plate for adsorption of reactive orange 16 (RO16) dye was successfully studied using the direct casting technique. Adsorption experiments were performed as a function of contact time, initial dye concentration (25mg/L to 350mg/L), and pH (3-11). The adsorption isotherm followed the Langmuir model. The adsorption capacity of CLECTF for RO16 was 356.50mg/g at 27±2°C. The kinetics closely followed the pseudo-second-order model. Results supported the potential use of an immobilized CLECTF as effective adsorbent for the treatment of reactive dye without using filtration process.

  9. Spectroscopic ellipsometry of Zn(1-x)Cu(x)O thin films based on a modified sol-gel dip-coating technique.

    PubMed

    Al-Khanbashi, Hibah A; Shirbeeny, W; Al-Ghamdi, A A; Bronstein, Lyudmila M; Mahmoud, Waleed E

    2014-01-24

    Nanocrystalline Zn(1-x)Cu(x)O thin films (x=0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by sol-gel dip-coating technique on a quartz substrate. These films were annealed at 350°C for 2 h. The X-ray diffraction showed a hexagonal crystal structure with high intensity peak for the (002) reflection plane indicating preferential growth along the c-axis of the crystal lattice. The peak position related to the (002) peak was shifted as a result of the copper ion incorporation, confirming the interstitial substitution of the zinc ions by the copper ions. This interstitial substitution leads to a decrease of an average crystallite size and lattice constants and an increase of the micro-strain up to 2 at.% of the copper amount. The surface morphology was explored by scanning electron microscopy which confirmed the homogenous distribution of nanoparticles in the deposited films along the quartz substrates. The energy dispersion X-ray spectroscopy revealed absence of impurities in the as-deposited films. The high resolution electron microscopy and selected area electron diffraction depicted that the films have polycrystalline nature. The film thickness and optical constants of the Zn(1-x)Cu(x)O thin films were estimated by fitting the spectroscopic ellipsometric data (ψ and Δ) using three different models. The refractive index was fitted using harmonic oscillator model from which the oscillator and the dispersive energies were found. The dielectric constant, dielectric loss, energy loss functions were also determined.

  10. Spectroscopic ellipsometry of Zn1-xCuxO thin films based on a modified sol-gel dip-coating technique

    NASA Astrophysics Data System (ADS)

    Al-Khanbashi, Hibah A.; Shirbeeny, W.; Al-Ghamdi, A. A.; Bronstein, Lyudmila M.; Mahmoud, Waleed E.

    2014-01-01

    Nanocrystalline Zn1-xCuxO thin films (x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by sol-gel dip-coating technique on a quartz substrate. These films were annealed at 350 °C for 2 h. The X-ray diffraction showed a hexagonal crystal structure with high intensity peak for the (0 0 2) reflection plane indicating preferential growth along the c-axis of the crystal lattice. The peak position related to the (0 0 2) peak was shifted as a result of the copper ion incorporation, confirming the interstitial substitution of the zinc ions by the copper ions. This interstitial substitution leads to a decrease of an average crystallite size and lattice constants and an increase of the micro-strain up to 2 at.% of the copper amount. The surface morphology was explored by scanning electron microscopy which confirmed the homogenous distribution of nanoparticles in the deposited films along the quartz substrates. The energy dispersion X-ray spectroscopy revealed absence of impurities in the as-deposited films. The high resolution electron microscopy and selected area electron diffraction depicted that the films have polycrystalline nature. The film thickness and optical constants of the Zn1-xCuxO thin films were estimated by fitting the spectroscopic ellipsometric data (ψ and Δ) using three different models. The refractive index was fitted using harmonic oscillator model from which the oscillator and the dispersive energies were found. The dielectric constant, dielectric loss, energy loss functions were also determined.

  11. Morphological and physicochemical properties of dip-coated poly {(2,5-diyl pyrrole) [4-nitrobenzylidène]} (PPNB) thin films: towards photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Mouchaal, Younes; Gherrass, Hamou; Bendoukha Reguig, Abdelkarim; Hachemaoui, Aïcha; Yahiaoui, Ahmed; Makha, Mohamed; Khelil, Abdelbacet; Bernede, Jean-Christian

    2015-02-01

    A new material: conjugated poly {(2,5-diyl pyrrole) [4-nitrobenzylidène]}, that we called (PPNB), has been synthesized and characterized. The cyclic voltammetry has been used in order to estimate first oxidation (Ep) and reduction (En) potentials of our polymer. These values have been assigned, respectively, to the position of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and determination of the energy band gap which have been estimated to be 6.16, 3.89 and 2.27 eV respectively. Energy levels values of the HOMO and LUMO of the PPNB polymeric donor material were evaluated and the results are compatible with an electron transfer to C60 within an eventual junction, such values show that PPNB could be probed for applications in organic solar cells as donor material. PPNB Thin films have been deposited by dip-coating technique from Dichloromethane solvent with different polymer concentrations, and a dipping speed of 3.0 cm/min. For morphological characterization of the films scanning electron microscopy (SEM) was carried out. The samples, when observed by SEM, reveals that the films deposited are less dense, uniform. Cross-sectional SEM micrographs PPNB films show that thickness of the layers is homogeneous and has value of 35-40 nm. Optical characteristics of the polymer thin films were studied using UV-vis spectroscopy; absorption of wide range of wavelengths from 350 to 700 nm was observed. The optical band gap energy ranges between 1.9 eV and 1.94 eV. Based on these analyzes we realized heterojunction organic solar cells with the structure: ITO/Au/PPNB/C60/BCP/Al, the cells had a photovoltaique effect after J-V measuring, however the efficiency of photo generation under AM1.5 illumination was weak (about 0.02%) and needs to be improved.

  12. A Solid-State Thin-Film Ag/AgCl Reference Electrode Coated with Graphene Oxide and Its Use in a pH Sensor

    PubMed Central

    Kim, Tae Yong; Hong, Sung A; Yang, Sung

    2015-01-01

    In this study, we describe a novel solid-state thin-film Ag/AgCl reference electrode (SSRE) that was coated with a protective layer of graphene oxide (GO). This layer was prepared by drop casting a solution of GO on the Ag/AgCl thin film. The potential differences exhibited by the SSRE were less than 2 mV for 26 days. The cyclic voltammograms of the SSRE were almost similar to those of a commercial reference electrode, while the diffusion coefficient of Fe(CN)63− as calculated from the cathodic peaks of the SSRE was 6.48 × 10−6 cm2/s. The SSRE was used in conjunction with a laboratory-made working electrode to determine its suitability for practical use. The average pH sensitivity of this combined sensor was 58.5 mV/pH in the acid-to-base direction; the correlation coefficient was greater than 0.99. In addition, an integrated pH sensor that included the SSRE was packaged in a secure digital (SD) card and tested. The average sensitivity of the chip was 56.8 mV/pH, with the correlation coefficient being greater than 0.99. In addition, a pH sensing test was also performed by using a laboratory-made potentiometer, which showed a sensitivity of 55.4 mV/pH, with the correlation coefficient being greater than 0.99. PMID:25789490

  13. Effect of calcinations temperature on microstructures, photocatalytic activity and self-cleaning property of TiO2 and SnO2/TiO2 thin films prepared by sol-gel dip coating process

    NASA Astrophysics Data System (ADS)

    Sangchay, Weerachai

    2014-06-01

    The purpose of this research was to study the effect of calcinations temperature on phase transformation, crystallite size, morphology, photocatalytic activity and self-cleaning properties of TiO2 and SnO2/TiO2 thin films. The thin films were preparation by sol-gel dip coating process and calcinations at the temperature of 500 °C, 600 °C and 700 °C for 2 h with the heating rate of 10 °C/mim. The microstructures of the fabricated thin films were characterized by XRD and SEM techniques. The photocatalytic activity of the thin films was also tested via the degradation of methylene blue solution under UV irradiation. Finally, self-cleaning properties of thin films were evaluated by measuring the contact angle of water droplet on the thin films with and without UV irradiation. It was found that SnO2/TiO2 thin films calcinations at the temperature of 500 °C shows the highest of photocatalytic activity and self-cleaning properties.

  14. COATING METHOD

    DOEpatents

    Townsend, R.G.

    1959-08-25

    A method is described for protectively coating beryllium metal by etching the metal in an acid bath, immersing the etched beryllium in a solution of sodium zincate for a brief period of time, immersing the beryllium in concentrated nitric acid, immersing the beryhlium in a second solution of sodium zincate, electroplating a thin layer of copper over the beryllium, and finally electroplating a layer of chromium over the copper layer.

  15. Hydrodynamics of dip-coated thin films in the presence of evaporation, and, Surfactant structures controlling spontaneous dewetting

    NASA Astrophysics Data System (ADS)

    Qu, Dan

    In this dissertation, we discuss the investigation of two problems in dynamic wetting: the hydrodynamics of dip-coated, finite-length films of evaporative fluids and the surfactant structures controlling the spontaneous dewetting of a surfactant solution. While films pulled from non-volatile fluids on a vertical substrate are essentially infinite in length, films pulled from volatile fluids have a finite length. We examine such finite films using three well-controlled oligomer liquids as well as surfactant solutions. We find that the finite length of the film is controlled by a global balance between mass lost by evaporation and mass input by viscous forces. While the attendant thermally driven Marangoni flows have small impact on the mass balance, they do alter the velocity field in the film in the direction parallel to the substrate. Using measured film profiles, wit have developed a novel method to determine the combined effects of evaporation and Marangoni flow on velocity and pressure fields in the film. This method is independent of any specific model of the evaporation process. In preliminary studies with surfactant solutions, we observed strong effects of solutal Marangoni flows on dip-coated films. For the second problem, we examine the structures of self-assemblies left on a solid as a contact line spontaneously retreats across a surface during an autophobing event. We find that surfactants of a continuous structural gradient are deposited: from molecules lying down on the surface with low packing densities in a region never touched by the solution, to molecules standing up with higher packing densities in a region where the contact line has moved slowly. Despite significant free volumes within the self-assemblies, we see no evidence of clustering of molecules. We see a clear correlation between contact line speed and the surfactant structures. We show that the dynamics during at least a later period of the autophobing event is dominated by the time

  16. Biphasic materials for bone grafting and hyperthermia treatment of cancer.

    PubMed

    Arcos, D; del Real, R P; Vallet-Regí, M

    2003-04-01

    Three biphasic materials have been synthesized from a magnetic glass-ceramic (Si-Ca-Fe) and a bioactive sol-gel glass (Si-P-Ca). The ratios of glass-ceramic:sol-gel glass used in this work were 1:1, 2:1, and 5:1. These materials show bioactive and magnetic properties and can be used as thermoseeds for hyperthermia treatment of bone tumors. The sol-gel glass content affects the textural properties of the glass-ceramic, giving rise to porosity, which plays a fundamental role in the formation of an apatite-like layer on the surface. On the other hand, as the sol-gel glass content increases, the magnetic properties change due to the diffusion of Fe ions to the glassy phases of the biphasic materials. The biphasic nature of these materials allows the changing of both properties, depending on the requirements of the patient.

  17. Progress on the biphase turbine at Cerro Prieto

    SciTech Connect

    Cerini, D.; Hays, L.; Studhalter, W.

    1997-12-31

    The status of a Biphase turbine power plant being installed at the Cerro Prieto geothermal field is presented. The major modules for the power plant are completed except for a back pressure steam turbine. The power plant will be started in April 1997 with the Biphase turbine alone followed by the addition of the steam turbine module two months later. The current power plant performance level is 2780 kWe due to a decline in the well. An increase in power output to 4060 kWe by adding the flow from another well is planned. The addition of five Biphase power plants with a total power output of 21.2 megawatts is described.

  18. Tunable biphasic drug release from ethyl cellulose nanofibers fabricated using a modified coaxial electrospinning process

    NASA Astrophysics Data System (ADS)

    Li, Chen; Wang, Zhuan-Hua; Yu, Deng-Guang; Williams, Gareth R.

    2014-05-01

    This manuscript reports a new type of drug-loaded core-shell nanofibers that provide tunable biphasic release of quercetin. The nanofibers were fabricated using a modified coaxial electrospinning process, in which a polyvinyl chloride (PVC)-coated concentric spinneret was employed. Poly (vinyl pyrrolidone) (PVP) and ethyl cellulose (EC) were used as the polymer matrices to form the shell and core parts of the nanofibers, respectively. Scanning and transmission electron microscopy demonstrated that the nanofibers had linear morphologies and core-shell structures. The quercetin was found to be present in the nanofibers in the amorphous physical status, on the basis of X-ray diffraction results. In vitro release profiles showed that the PVP shell very rapidly freed its drug cargo into the solution, while the EC core provided the succedent sustained release. Variation of the drug loading permitted the release profiles to be tuned.

  19. Modulation of ultrafast laser-induced magnetization precession in BiFeO3-coated La0.67Sr0.33MnO3 thin films

    NASA Astrophysics Data System (ADS)

    Wan, Qian; Jin, KuiJuan; Wang, JieSu; Yao, HongBao; Gu, JunXing; Guo, HaiZhong; Xu, XiuLai; Yang, GuoZhen

    2017-04-01

    The ultrafast laser-excited magnetization dynamics of ferromagnetic (FM) La0.67Sr0.33MnO3 (LSMO) thin films with BiFeO3 (BFO) coating layers grown by laser molecular beam epitaxy are investigated using the optical pump-probe technique. Uniform magnetization precessions are observed in the films under an applied external magnetic field by measuring the time-resolved magneto-optical Kerr effect. The magnetization precession frequencies of the LSMO thin films with the BFO coating layers are lower than those of uncoated LSMO films, which is attributed to the suppression of the anisotropy field induced by the exchange interaction at the interface between the antiferromagnetic order of BFO and the FM order of LSMO.

  20. Plasma Diagnostics for Plasma Polymer Coatings Used in Fabrication of Thin Wall CH Shells for Direct Drive OMEGA Cryogenic Experiments

    NASA Astrophysics Data System (ADS)

    Ross, P.; Nikroo, A.; Czechowicz, D.; Dicken, M.

    2002-11-01

    High aspect ratio CH shells, 1 μm thick, 9001 μm diameter, are crucial for the success of the cryogenic direct drive inertial confinement fusion (ICF) experiments at the OMEGA laser facility at the University of Rochester's Laboratory for Laser Energetics (LLE). Plasma polymer coatings are currently used in fabrication of such shells, which can be made substantially stronger by altering parameters. High strength is important for inherently fragile high aspect ratio shells. The plasma characteristics used in the deposition process were studied in order to determine a correlation between the plasma parameters and the strength of shells. Several plasma processing parameters such as deposition pressure, power and relative and absolute gas flow rates were varied. The plasma was studied using several techniques such as optical emission spectroscopy, Langmuir probe diagnostics, and mass spectrometry. These diagnostic results were then correlated with direct measurements of the target strength (burst testing and buckle testing) and permeability to determine the ideal parameters for creating the strongest and most permeable ICF targets.

  1. Microfluidic electrospinning of biphasic nanofibers with Janus morphology

    PubMed Central

    Srivastava, Yasmin; Marquez, Manuel; Thorsen, Todd

    2009-01-01

    In this paper a method of electrospinning conducting and nonconducting biphasic Janus nanofibers using microfluidic polydimethylsiloxane (PDMS)-based manifolds is described. Key benefits of using microfluidic devices for nanofiber synthesis include rapid prototyping, ease of fabrication, and the ability to spin multiple Janus fibers in parallel through arrays of individual microchannels. Biphasic Janus nanofibers of polyvinylpyrrolidone (PVP)+polypyrrole (PPy)∕PVP nanofibers with an average diameter of 250 nm were successfully fabricated using elastomeric microfluidic devices. Fiber characterization and confirmation of the Janus morphology was subsequently carried out using a combination of scanning electron microscopy, energy dispersion spectroscopy, and transmission electron microscopy. PMID:19693390

  2. Case Report: Multifocal biphasic squamoid alveolar renal cell carcinoma

    PubMed Central

    Lopez, Jose Ignacio

    2016-01-01

    A multifocal biphasic squamoid alveolar renal cell carcinoma in a 68-year-old man is reported. Four different peripheral tumor nodules were identified on gross examination. A fifth central tumor corresponded to a conventional clear cell renal cell carcinoma. Biphasic squamoid alveolar renal cell carcinoma is a rare tumor that has been very recently characterized as a distinct histotype within the spectrum of papillary renal cell carcinoma. Immunostaining with cyclin D1 seems to be specific of this tumor subtype. This is the first reported case with multifocal presentation. PMID:27158455

  3. Transmission photocathodes based on stainless steel mesh and quartz glass coated with N-doped DLC thin films prepared by reactive magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Balalykin, N. I.; Huran, J.; Nozdrin, M. A.; Feshchenko, A. A.; Kobzev, A. P.; Arbet, J.

    2016-03-01

    The influence was investigated of N-doped diamond-like carbon (DLC) films properties on the quantum efficiency of a prepared transmission photocathode. N-doped DLC thin films were deposited on a silicon substrate, a stainless steel mesh and quartz glass (coated with 5 nm thick Cr adhesion film) by reactive magnetron sputtering using a carbon target and gas mixture Ar, 90%N2+10%H2. The elements' concentration in the films was determined by RBS and ERD. The quantum efficiency was calculated from the measured laser energy and the measured cathode charge. For the study of the vectorial photoelectric effect, the quartz type photocathode was irradiated by intensive laser pulses to form pin-holes in the DLC film. The quantum efficiency (QE), calculated at a laser energy of 0.4 mJ, rose as the nitrogen concentration in the DLC films was increased and rose dramatically after the micron-size perforation in the quartz type photocathodes.

  4. Crack suppression of silica glass formed by zoned F2 laser-induced photochemical surface modification of hard silicone thin film coating on polycarbonate

    NASA Astrophysics Data System (ADS)

    Nojiri, Hidetoshi; Okoshi, Masayuki

    2016-12-01

    The surface layer of a hard silicone thin film coating on polycarbonate was modified to silica glass (SiO2) through F2-laser-induced photochemical reactions. To obtain samples with higher abrasion resistances, SiO2 films of 1 µm thickness and over were successfully formed without cracking, by zoning the laser-irradiated area of micrometer order. With the conversion of silicone to SiO2, the volumetric shrinkage of the sample was induced, which simply depended on the number of photons, by varying the single-pulse fluence and irradiation time of a F2 laser. The ratio of volumetric shrinkage to the original silicone was estimated to be approximately 0.85, generating tensile stress in SiO2. The stress could be suppressed to be lower than 48 MPa for typical SiO2 by reducing the laser-irradiated area to be of micrometer order. Also, when the length of one side of the irradiated area is 1 mm, the thickness of the SiO2 film is expected to increase to approximately 5 µm.

  5. Partial PEGylation of superparamagnetic iron oxide nanoparticles thinly coated with amine-silane as a source of ultrastable tunable nanosystems for biomedical applications.

    PubMed

    Cano, Manuel; Núñez-Lozano, Rebeca; Lumbreras, Rocío; González-Rodríguez, Verena; Delgado-García, Alberto; Jiménez-Hoyuela, José Manuel; de la Cueva-Méndez, Guillermo

    2017-01-05

    The development of superparamagnetic iron oxide nanoparticle (SPION)-based diagnostic and therapeutic nanosystems holds a promise of revolutionizing biomedicine, helping to solve important unmet clinical needs. Such potential will only be fulfilled if appropriate methods for SPION production and for their subsequent tailoring to specific applications are established, something that remains challenging. Here, we report a simple and low cost method to fabricate structurally and colloidally ultrastable, water soluble SPIONs. We used thermal decomposition to produce SPIONs of the highest quality, which were then thinly coated with an amine-silane derivative by ligand exchange, conferring hydrophilicity and great structural stability on the nanoparticles. Subsequent partial covalent occupancy of surface amine groups with polyethyleneglycol (PEG) was carried out to give them excellent colloidal stability, whilst still leaving reactive anchoring points for further functionalization. The correct composition and physicochemical properties of our PEGylated SPIONs and their precursors were confirmed using a broad range of analytical techniques, and we also demonstrated the biocompatible character of the resulting nanoparticles, as well as their suitability as T2 MRI contrast agents in vivo. Finally, using a near infra-red fluorophore, we also confirmed that these SPIONs are amenable to further tuning, to adapt them to a wide range of applications or to optimize their performance in particular settings. In summary, our work provides a novel and robust method for the production of SPIONs that can be used as a tunable platform for the development of smart diagnostic and therapeutic nanosystems.

  6. Fabrication of a thermoelectric generator on a polymer-coated substrate via laser-induced forward transfer of chalcogenide thin films

    NASA Astrophysics Data System (ADS)

    Feinaeugle, M.; Sones, C. L.; Koukharenko, E.; Eason, R. W.

    2013-11-01

    We have demonstrated the fabrication of a thermoelectric energy harvesting device via laser-induced forward transfer of intact solid thin films. Thermoelectric chalcogenide materials, namely bismuth telluride (Bi2Te3), bismuth selenide (Bi2Se3) and bismuth antimony telluride (Bi0.5Sb1.5Te3), were sequentially printed using a nanosecond excimer laser onto an elastomeric polydimethylsiloxane-coated glass substrate to form thermocouples connected in series creating a thermoelectric generator. The resulting generator Seebeck coefficient and series resistance per leg pair were measured to be 0.17 mV K-1 and 10 kΩ respectively. It was shown that laser-induced forward transfer allows device fabrication from inorganic semiconductor compounds on inexpensive elastic polymer substrates and demonstrates the ability to print materials with pre-defined thermoelectric properties. This allows the rapid manufacturing of a complete thermoelectric device on mm2-areas with μm-scale precision, without the need of further lithographic steps.

  7. Annealing effects on structural, electrical and optical properties of antimony-tinoxide thin films deposited by sol gel dip coating technique

    NASA Astrophysics Data System (ADS)

    Lekshmy, S. Sujatha; Anitha, V. S.; Berlin, I. John; Joy, K.

    2014-01-01

    Antimony-doped tin dioxide possess interesting physical and chemical properties. These properties have a wide range of applications such as catalysis and optoelectronic devices. In the present study, antimony-doped tin oxide (SnO2:Sb) thin films were deposited on the quartz substrates by sol-gel dip coating technique. The films were annealed at temperatures 350°C, 550°C and 850°C in air for 2 hours. The structure and surface morphologies were observed by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). XRD patterns shows tetragonal structure for the SnO2:Sb films annealed at different temperatures. Crystallite size increased from 6 to 14 nm as annealing temperature increased from 350°C to 850°C. SEM studies reveals crack free and smooth surface for all the films. The grains are found to be homogenously distributed for films annealed at higher temperature. The electrical conductivity of the films annealed at 350°C and 550°C decreased and increased for the films annealed at 850°C. The optical properties of the films were investigated in the UV-visible-NIR region (200-900 nm) using UV spectra. The transmittance of the films decreased for films annealed at higher temperature. The optical energy band gap values (4.13 eV-4.83 eV) increased with the increase in annealing temperature.

  8. Silicon nitride anti-reflection coating on the glass and transparent conductive oxide interface for thin film solar cells and modules

    NASA Astrophysics Data System (ADS)

    Iwahashi, T.; Morishima, M.; Fujibayashi, T.; Yang, R.; Lin, J.; Matsunaga, D.

    2015-10-01

    Anti-reflection coating (ARC) is well known as an important technique to enhance solar cell performance. Typical ARC has been applied on the glass surface to reduce light reflection loss at the air/glass interface. However, reflection loss occurs not only at glass surface but also at other interfaces such as glass/transparent conductive oxide (TCO) interface. The refractive index of SiNx is tunable from 1.6 to 2.7, and the range from 1.7 to 2.0 is suitable for ARC at glass/TCO interface. In this study, we examined the AR effect of silicon nitride (SiNx) deposited by plasma enhanced chemical vapor deposition at the glass/TCO interface with thin film silicon solar cell and module. Reflectivity reduction of 1.6% for glass/ZnO substrate has been obtained with optimal SiNx layer, which contribute 2.0% gain in cell efficiency. Besides, we also confirmed the relative efficiency gain of around 2% for large-sized solar module, leading to a world-record large area stabilized module conversion efficiency of 12.34%.

  9. Annealing effects on structural, electrical and optical properties of antimony-tinoxide thin films deposited by sol gel dip coating technique

    SciTech Connect

    Lekshmy, S. Sujatha Anitha, V. S. Berlin, I. John Joy, K.

    2014-01-28

    Antimony-doped tin dioxide possess interesting physical and chemical properties. These properties have a wide range of applications such as catalysis and optoelectronic devices. In the present study, antimony-doped tin oxide (SnO2:Sb) thin films were deposited on the quartz substrates by sol-gel dip coating technique. The films were annealed at temperatures 350°C, 550°C and 850°C in air for 2 hours. The structure and surface morphologies were observed by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). XRD patterns shows tetragonal structure for the SnO2:Sb films annealed at different temperatures. Crystallite size increased from 6 to 14 nm as annealing temperature increased from 350°C to 850°C. SEM studies reveals crack free and smooth surface for all the films. The grains are found to be homogenously distributed for films annealed at higher temperature. The electrical conductivity of the films annealed at 350°C and 550°C decreased and increased for the films annealed at 850°C. The optical properties of the films were investigated in the UV-visible-NIR region (200-900 nm) using UV spectra. The transmittance of the films decreased for films annealed at higher temperature. The optical energy band gap values (4.13 eV-4.83 eV) increased with the increase in annealing temperature.

  10. Influence of Ga doping ratio on the saturable absorption mechanism in Ga doped ZnO thin solid films processed by sol–gel spin coating technique

    NASA Astrophysics Data System (ADS)

    Sandeep, K. M.; Bhat, Shreesha; Dharmaprakash, S. M.; Byrappa, K.

    2017-03-01

    In the present study, the nonlinear optical properties of sol–gel spin coated gallium doped zinc oxide (GZO) thin solid films are explored with nanosecond laser pulses using the z-scan technique. The higher doping ratios of Ga result in a large redshift of the energy gap (0.38 eV) due to the existence of enhanced grain boundary defects in GZO films. A positive nonlinear absorption coefficient is observed in undoped 1 at.wt.% GZO and 2 at.wt.% GZO films, and a negative nonlinear absorption coefficient in 3 at.wt.% GZO film. Fewer defects in undoped 1% GZO and 2% GZO films resulted in reverse saturable absorption (RSA), whereas a saturable absorption (SA) mechanism is observed in 3% GZO films and is attributed to the enhanced defect concentration in the band structure of GZO. However, all the films showed a self-defocusing mechanism, derived by a closed aperture z-scan technique. The present work sheds light on the defect mechanism involved in the observed nonlinear properties of GZO films.

  11. Sensing of digestive proteins in saliva with a molecularly imprinted poly(ethylene-co-vinyl alcohol) thin film coated quartz crystal microbalance sensor.

    PubMed

    Lee, Mei-Hwa; Thomas, James L; Tseng, Hong-Yi; Lin, Wei-Che; Liu, Bin-Da; Lin, Hung-Yin

    2011-08-01

    The quartz crystal microbalance (QCM) has a sensitivity comparable to that of the surface plasmon resonance (SPR) transducer. Molecularly imprinted polymers (MIPs) have a much lower cost than natural antibodies, they are easier to fabricate and more stable, and they exhibit satisfactory recognition ability when integrated onto sensing transducers. Hence, MIP-based QCM sensors have been used to recognize small molecules and, recently, microorganisms, but only a few have been adopted in protein sensing. In this work, a mixed salivary protein and poly(ethylene-co-vinyl alcohol), EVAL, solution is coated onto a QCM chip and a molecularly imprinted EVAL thin film formed by thermally induced phase separation (TIPS). The optimal ethylene mole ratios of the commercially available EVALs for the imprinting of amylase, lipase and lysozyme were found to be 32, 38, and 44 mol %, respectively. Finally, the salivary protein-imprinted EVAL-based QCM sensors were used to detect amylase, lipase and lysozyme in real samples (saliva) and their effectiveness was compared with that of a commercial ARCHITECT ci 8200 chemical analysis system. The limits of detection (LOD) for those salivary proteins were as low as ∼pM.

  12. Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    1993-01-01

    In order to reduce heat transfer between a hot gas heat source and a metallic engine component, a thermal insulating layer of material is placed between them. This thermal barrier coating is applied by plasma spray processing the thin films. The coating has been successfully employed in aerospace applications for many years. Lewis Research Center, a leader in the development engine components coating technology, has assisted Caterpillar, Inc. in applying ceramic thermal barrier coatings on engines. Because these large engines use heavy fuels containing vanadium, engine valve life is sharply decreased. The barrier coating controls temperatures, extends valve life and reduces operating cost. Additional applications are currently under development.

  13. Effect of longitudinal electric field on capillary instability of a thin axisymmetric layer of liquid dielectric coating a dielectric fiber

    NASA Astrophysics Data System (ADS)

    Korovin, V. M.

    2016-12-01

    The flow of a viscous dielectric liquid surrounded with a gas is investigated in the process of capillary disintegration of a thin axisymmetric liquid layer on an undeformable cylindrical dielectric fiber in a uniform electric field is investigated. An asymptotic analysis of the system of equations and hydrodynamic boundary conditions written with allowance for surface ponderomotive forces is carried out for the case when the average thickness of the layer is much smaller than the radius of the fiber cross section. The problem of the transition of the liquid configuration from the state of a stationary cylindrical layer to the hydrodynamic state in the form of a regular sequence of drops is formulated. In this formulation, a nonlinear parabolic equation that describes the evolution of the local thickness of the layer on the time interval to the instant of drop formation is derived. The effect of the key parameters on the capillary instability is analyzed based on the linearized version of the resultant equation and the linearized electrostatic problem of calculating the field perturbations.

  14. Detection of water in jet fuel using layer-by-layer thin film coated long period grating sensor.

    PubMed

    Puckett, Sean D; Pacey, Gilbert E

    2009-04-15

    The quantitative measurement of jet fuel additives in the field is of interest to the Air Force. The "smart nozzle" project was designed as a state-of-the-art diagnostics package attached to a single-point refueling nozzle for assessing key fuel properties as the fuel is dispensed. The objective of the work was to show proof of concept that a layer-by-layer thin film and long period grating fibers could be used to detect the presence of water in jet fuel. The data for the nafion/PDMA film and a long period grating fiber is a combination capable of quantitative measurement of water in kerosene. The average response (spectral loss wavelength shift) to the kerosene sample ranged from -6.0 for 15 ppm to -126.5 for 60 ppm water. The average calculated value for the check standard was 21.71 and ranged from 21.25 to 22.00 with a true value of 22.5 ppm water. Potential interferences were observed and are judged to be insignificant in real samples.

  15. Coating of plasma polymerized film

    NASA Technical Reports Server (NTRS)

    Morita, S.; Ishibashi, S.

    1980-01-01

    Plasma polymerized thin film coating and the use of other coatings is suggested for passivation film, thin film used for conducting light, and solid body lubrication film of dielectrics of ultra insulators for electrical conduction, electron accessories, etc. The special features of flow discharge development and the polymerized film growth mechanism are discussed.

  16. A biphasic model for micro-indentation of a hydrogel-based contact lens.

    PubMed

    Chen, Xiaoming; Dunn, Alison C; Sawyer, W Gregory; Sarntinoranont, Malisa

    2007-04-01

    The stiffness and hydraulic permeability of soft contact lenses may influence its clinical performance, e.g., on-eye movement, fitting, and wettability, and may be related to the occurrence of complications; e.g., lesions. It is therefore important to determine these properties in the design of comfortable contact lenses. Micro-indentation provides a nondestructive means of measuring mechanical properties of soft, hydrated contact lenses. However, certain geometrical and material considerations must be taken into account when analyzing output force-displacement (F-D) data. Rather than solely having a solid response, mechanical behavior of hydrogel contact lenses can be described as the coupled interaction between fluid transport through pores and solid matrix deformation. In addition, indentation of thin membranes ( approximately 100 microm) requires special consideration of boundary conditions at lens surfaces and at the indenter contact region. In this study, a biphasic finite element model was developed to simulate the micro-indentation of a hydrogel contact lens. The model accounts for a curved, thin hydrogel membrane supported on an impermeable mold. A time-varying boundary condition was implemented to model the contact interface between the impermeable spherical indenter and the lens. Parametric studies varying the indentation velocities and hydraulic permeability show F-D curves have a sensitive region outside of which the force response reaches asymptotic limits governed by either the solid matrix (slow indentation velocity, large permeability) or the fluid transport (high indentation velocity, low permeability). Using these results, biphasic properties (Young's modulus and hydraulic permeability) were estimated by fitting model results to F-D curves obtained at multiple indentation velocities (1.2 and 20 microm/s). Fitting to micro-indentation tests of Etafilcon A resulted in an estimated permeability range of 1.0 x 10(-15) to 5.0 x 10(-15) m(4)N s and

  17. A biphasic basal body temperature record during pregnancy.

    PubMed

    Urman, B C; McComb, P F

    1989-01-01

    A case of biphasic temperature record is reported during the course of an ectopic pregnancy. Possible implications of this phenomenon may improve our understanding of the role of ovum transmigration and the endocrinological interaction of pregnancy with hormonal control of ovulation.

  18. TREATMENT OF TYPE 2 DIABETES WITH BIPHASIC INSULIN ANALOGUES

    PubMed Central

    Rizvi, Ali A.

    2016-01-01

    The majority of patients with Type 2 diabetes require insulin therapy for treating hyperglycaemia. There are several regimens available for insulin initiation and maintenance. Insulin analogues have been developed to mimic normal physiology as closely as possible. Biphasic analogues can target both fasting and postprandial hyperglycaemia, with the added advantage of being premixed and thus convenient for the patient. A practical and feasible option is to initiate insulin with one or more biphasic preparations at mealtimes, thus providing both basal and prandial coverage. Individual titration of dose and frequency of daily injections with biphasic insulin preparations has the potential for improving glycaemic control with a high degree of patient acceptance. Drawbacks include a more rigid regimen, a relative lack of flexibility, and a somewhat higher degree of glycaemic variability and hypoglycaemia when compared to multiple daily basal-bolus injections. Awareness of the advantages and limitations of biphasic insulin analogues can assist clinicians in their appropriate use for the treatment of patients with Type 2 diabetes. PMID:27918600

  19. Biphasic dose response in low level light therapy - an update.

    PubMed

    Huang, Ying-Ying; Sharma, Sulbha K; Carroll, James; Hamblin, Michael R

    2011-01-01

    Low-level laser (light) therapy (LLLT) has been known since 1967 but still remains controversial due to incomplete understanding of the basic mechanisms and the selection of inappropriate dosimetric parameters that led to negative studies. The biphasic dose-response or Arndt-Schulz curve in LLLT has been shown both in vitro studies and in animal experiments. This review will provide an update to our previous (Huang et al. 2009) coverage of this topic. In vitro mediators of LLLT such as adenosine triphosphate (ATP) and mitochondrial membrane potential show biphasic patterns, while others such as mitochondrial reactive oxygen species show a triphasic dose-response with two distinct peaks. The Janus nature of reactive oxygen species (ROS) that may act as a beneficial signaling molecule at low concentrations and a harmful cytotoxic agent at high concentrations, may partly explain the observed responses in vivo. Transcranial LLLT for traumatic brain injury (TBI) in mice shows a distinct biphasic pattern with peaks in beneficial neurological effects observed when the number of treatments is varied, and when the energy density of an individual treatment is varied. Further understanding of the extent to which biphasic dose responses apply in LLLT will be necessary to optimize clinical treatments.

  20. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

  1. Thin Film Inorganic Electrochemical Systems.

    DTIC Science & Technology

    1995-07-01

    determined that thin film cathodes of LiCoO2 can be readily performed by either spray pyrolysis or spin coating . These cathodes are electrochemically...active. We have also determined that thin film anodes of Li4Ti5O12 can be prepared by spray pyrolysis or spin coating . These anodes are also

  2. Electrochemical Characterization of CdSe-Coated ZnO Nanowire Extremely-Thin-Absorber Solar Cells

    NASA Astrophysics Data System (ADS)

    Jones, Treavor Zachary

    Four different CdSe-coated nanostructured ZnO ETA configurations as photoelectrochemical cells with polysulfide electrolyte were studied using both conventional and electrochemical characterization techniques. ETA configurations with different ZnO nanowire lengths of 500 nm and 1000 nm were varied with different CdSe absorber-layer thicknesses of 15 nm and 45 nm to examine the effects on PV performance, carrier transport, and carrier recombination. Linear-sweep voltammetry (J-V) measurements showed that longer ZnO nanowires with thinner CdSe absorber layers gave better PV performance with the 1000 nm length/15 nm CdSe thickness samples having the highest JSC ˜4.4 mA/cm2, VOC ˜0.38 V, Pmax ˜0.52 mW/cm2, and second-highest FF ˜0.32. Mott-Schottky (MS) analysis was performed on individual ETA-layer materials to obtain estimates of their ND and VFB for insight into how individual layers in an ETA cell can assist in carrier separation. MS results were shown to be irrespective of illumination, exposed area, or the electrolyte used. Annealed ZnO nanowires had an ND ˜2x10 19 cm-3, a VFB ˜(-0.4) V. versus Ag/AgCl, and were observed to be n-type. MS analysis of planar CdSe showed it to be slightly n-type and gave parameter estimates of ND ˜3x10 17 cm-3 and VFB ˜-1.1 V v. Ag/AgCl, which were also used to calculate its VBI to be ˜0.4 V, and its depletion width, W to be ˜44 nm. Carrier transport studies were performed using IMPS and photocurrent decay measurements to estimate the time constant for carrier transport, with the fastest observed for shorter nanowires and thicker CdSe absorber layers at ˜10 micros. Carrier recombination studies were also performed using IMVS, photovoltage decay, and EIS measurements to estimate the time constant for carrier recombination, with the slowest estimated for the samples with 45 nm CdSe thickness samples at ˜100 ms. Therefore, shorter nanowires with thicker CdSe absorber layers showed the best potential for improving carrier

  3. Advanced thin film thermocouples

    NASA Technical Reports Server (NTRS)

    Kreider, K. G.; Semancik, S.; Olson, C.

    1984-01-01

    The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

  4. 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.

  5. Effect of self-assembled nanofibrous silk/polycaprolactone layer on the osteoconductivity and mechanical properties of biphasic calcium phosphate scaffolds.

    PubMed

    Roohani-Esfahani, S I; Lu, Z F; Li, J J; Ellis-Behnke, R; Kaplan, D L; Zreiqat, H

    2012-01-01

    We here present the first successful report on combining nanostructured silk and poly(ε-caprolactone) (PCL) with a ceramic scaffold to produce a composite scaffold that is highly porous (porosity ∼85%, pore size ∼500 μm, ∼100% interconnectivity), strong and non-brittle with a surface that resembles extracellular matrix (ECM). The ECM-like surface was developed by self-assembly of nanofibrous structured silk (20-80 nm diameter, similar to native collagen found in ECM) over a thin PCL layer which is coated on biphasic calcium phosphate (BCP) scaffolds. The effects of different concentrations of silk solution on the mechanical and physical properties of the scaffolds were also comprehensively examined. Our results showed that using silk only (irrespective of concentration) for the modification of ceramic scaffolds could drastically reduce the compressive strength of the modified scaffolds in aqueous media, and the modification made a limited contribution to improving scaffold toughness. Using PCL/nanostructured silk the compressive strength and modulus of the modified scaffolds reached 0.42 MPa (compared with 0.07 MPa for BCP) and ∼25 MPa (compared with 5 MPa for BCP), respectively. The failure strain of the modified scaffold increased more than 6% compared with a BCP scaffold (failure strain of less than 1%), indicating a transformation from brittle to elastic behavior. The cytocompatibility of ECM-like composite scaffolds was investigated by studying the attachment, morphology, proliferation and bone-related gene expression of primary human bone-derived cells. Cells cultured on the developed scaffolds for 7 days had significant up-regulation of cell proliferation (∼1.6-fold higher, P<0.001) and osteogenic gene expression levels (collagen type I, osteocalcin and bone sialoprotein) compared with the other groups tested.

  6. The role of film interfaces in near-ultraviolet absorption and pulsed-laser damage in ion-beam-sputtered coatings based on HfO2/SiO2 thin-film pairs

    DOE PAGES

    Ristau, Detlev; Papernov, S.; Kozlov, A. A.; ...

    2015-11-23

    The role of thin-film interfaces in the near-ultraviolet absorption and pulsed-laser–induced damage was studied for ion-beam–sputtered and electron-beam–evaporated coatings comprised from HfO2 and SiO2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage-threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO2 single-layer film and for a film containing seven narrow HfO2 layers separated by SiO2 layers. The seven-layer film was designed to have a total optical thickness of HfO2 layers, equal to one wave at 355 nm and an E-field peak and average intensity similar to a single-layer HfO2more » film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces, as compared to HfO2 film material. The relevance of obtained absorption data to coating near-ultraviolet, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO2 film in both sputtered and evaporated coatings. Here, the results are explained through the similarity of interfacial film structure with structure formed during the co-deposition of HfO2 and SiO2 materials.« less

  7. The role of film interfaces in near-ultraviolet absorption and pulsed-laser damage in ion-beam-sputtered coatings based on HfO2/SiO2 thin-film pairs

    SciTech Connect

    Ristau, Detlev; Papernov, S.; Kozlov, A. A.; Oliver, J. B.; Smith, C.; Jensen, L.; Gunster, S.; Madebach, H.

    2015-11-23

    The role of thin-film interfaces in the near-ultraviolet absorption and pulsed-laser–induced damage was studied for ion-beam–sputtered and electron-beam–evaporated coatings comprised from HfO2 and SiO2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage-threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO2 single-layer film and for a film containing seven narrow HfO2 layers separated by SiO2 layers. The seven-layer film was designed to have a total optical thickness of HfO2 layers, equal to one wave at 355 nm and an E-field peak and average intensity similar to a single-layer HfO2 film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces, as compared to HfO2 film material. The relevance of obtained absorption data to coating near-ultraviolet, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO2 film in both sputtered and evaporated coatings. Here, the results are explained through the similarity of interfacial film structure with structure formed during the co-deposition of HfO2 and SiO2 materials.

  8. Phase separation in NiCrN coatings induced by N2 addition in the gas phase: A way to generate magnetic thin films by reactive sputtering of a non-magnetic NiCr target

    NASA Astrophysics Data System (ADS)

    Luciu, I.; Duday, D.; Choquet, P.; Perigo, E. A.; Michels, A.; Wirtz, T.

    2016-12-01

    Magnetic coatings are used for a lot of applications from data storage in hard discs, spintronics and sensors. Meanwhile, magnetron sputtering is a process largely used in industry for the deposition of thin films. Unfortunately, deposition of magnetic coatings by magnetron sputtering is a difficult task due to the screening effect of the magnetic target lowering the magnetic field strength of the magnet positioned below the target, which is used to generate and trap ions in the vicinity of the target surface to be sputtered. In this work we present an efficient method to obtain soft magnetic thin films by reactive sputtering of a non-magnetic target. The aim is to recover the magnetic properties of Ni after dealloying of Ni and Cr due to the selective reactivity of Cr with the reactive nitrogen species generated during the deposition process. The effects of nitrogen content on the dealloying and DC magnetron sputtering (DCMS) deposition processes are studied here. The different chemical compositions, microstructures and magnetic properties of DCMS thin films obtained by sputtering in reactive gas mixtures with different ratios of Ar/N2 from a non-magnetic Ni-20Cr target have been determined. XPS data indicate that the increase of nitrogen content in the films has a strong influence on the NiCr phase decomposition into Ni and CrN, leading to ferromagnetic coatings due to the Ni phase. XRD results show that the obtained Ni-CrN films consist of a metallic fcc cubic Ni phase mixed with fcc cubic CrN. The lattice parameter decreases with the N2 content and reaches the theoretical value of the pure fcc-Ni, when Cr is mostly removed from the Ni-Cr phase. Dealloying of Cr from a Ni80-Cr20 solid solution is achieved in our experimental conditions and the deposition of Ni ferromagnetic coatings embedding CrN from a non-magnetic target is possible with reactive DC magnetron sputtering.

  9. pH- and thermosensitive thin lipid layer coated mesoporous magnetic nanoassemblies as a dual drug delivery system towards thermochemotherapy of cancer.

    PubMed

    Pradhan, Lina; Srivastava, R; Bahadur, D

    2014-07-01

    A new pH-sensitive and thermosensitive dual drug delivery system consisting of thin lipid layer encapsulated mesoporous magnetite nanoassemblies (MMNA) has been developed which can deliver two anticancer drugs simultaneously. The formulation of lipid layer used is 5:2:2:2 w/w, DPPC:cholesterol:DSPE-PEG2000:MMNA. The structure, morphology and magnetic properties of MMNA and lipid coated MMNA (LMMNA) were thoroughly characterized. This hybrid system was investigated for its ability to carry two anticancer drugs as well as its ability to provide heat under an alternating current magnetic field (ACMF). A very high loading efficiency of up to ∼81% of doxorubicin hydrochloride (DOX) with an ∼0.02 mg mg(-1) loading capacity and ∼60% of paclitaxel (TXL) with an ∼0.03 mg mg(-1) loading capacity are obtained with LMMNA. A sustained release of drug is observed over a period of 172 h, with better release, of ∼88:53% (DOX:TXL), at pH 4.3 compared to the ∼28:26% (DOX:TXL) in physiological conditions (pH 7.4). An enhanced release of ∼72 and ∼68% is recorded for DOX and TXL, respectively, during the first hour with the application of an ACMF (∼43°C). A greater in vitro cytotoxic effect is observed with the two drugs compared to them individually in HeLa, MCF-7 and HepG2 cancer cells. With the application of an ACMF for 10 min, the cell killing efficiency is improved substantially due to simultaneous thermo- and chemotherapy. Confocal microscopy confirms the internalization of drug loaded MMNA and LMMNA by cells and their morphological changes during thermochemotherapy.

  10. Role of associated defects in oxygen ion conduction and surface exchange reaction for epitaxial samaria-doped ceria thin films as catalytic coatings

    DOE PAGES

    Yang, Nan; Shi, Yanuo; Schweiger, Sebastian; ...

    2016-05-18

    Samaria-doped ceria (SDC) thin films are particularly important for energy and electronic applications such as micro-solid oxide fuel cells, electrolysers, sensors and memristors. In this paper we report a comparative study investigating ionic conductivity and surface reactions for well-grown epitaxial SDC films varying the samaria doping concentration. With increasing doping above 20 mol% of samaria, an enhancement in the defect association was observed by Raman spectroscopy. The role of such defect associates on the films` oxygen ion transport and exchange was investigated by electrochemical impedance spectroscopy and electrochemical strain microscopy (ESM). The measurements reveal that the ionic transport has amore » sharp maximum in ionic conductivity and drop in its activation energy down to 0.6 eV for 20 mol% doping. Increasing the doping concentration further up to 40 mol%, raises the activation energy substantially by a factor of two. We ascribe the sluggish transport kinetics to the "bulk" ionic-near ordering in case of the heavily doped epitaxial films. Analysis of the ESM first order reversal curve measurements indicate that these associated defects may have a beneficial role by lowering the activation of the oxygen exchange "surface" reaction for heavily doped 40 mol% of samaria. We reveal in a model experiment through a solid solution series of samaria doped ceria epitaxial films that the occurrence of associate defects in the bulk affects the surface charging state of the films to increase the exchange rates. Lastly, the implication of these findings are the design of coatings with tuned oxygen surface exchange by control of bulk associate clusters for future electro-catalytic applications.« less

  11. Role of associated defects in oxygen ion conduction and surface exchange reaction for epitaxial samaria-doped ceria thin films as catalytic coatings

    SciTech Connect

    Yang, Nan; Shi, Yanuo; Schweiger, Sebastian; Strelcov, Evgheni; Foglietti, Vittorio; Orgiani, Pasquale; Balestrino, Giuseppe; Kalinin, Sergei V.; Jennifer L. M. Rupp; Aruta, Carmela; Belianinov, Alex

    2016-05-18

    Samaria-doped ceria (SDC) thin films are particularly important for energy and electronic applications such as micro-solid oxide fuel cells, electrolysers, sensors and memristors. In this paper we report a comparative study investigating ionic conductivity and surface reactions for well-grown epitaxial SDC films varying the samaria doping concentration. With increasing doping above 20 mol% of samaria, an enhancement in the defect association was observed by Raman spectroscopy. The role of such defect associates on the films` oxygen ion transport and exchange was investigated by electrochemical impedance spectroscopy and electrochemical strain microscopy (ESM). The measurements reveal that the ionic transport has a sharp maximum in ionic conductivity and drop in its activation energy down to 0.6 eV for 20 mol% doping. Increasing the doping concentration further up to 40 mol%, raises the activation energy substantially by a factor of two. We ascribe the sluggish transport kinetics to the "bulk" ionic-near ordering in case of the heavily doped epitaxial films. Analysis of the ESM first order reversal curve measurements indicate that these associated defects may have a beneficial role by lowering the activation of the oxygen exchange "surface" reaction for heavily doped 40 mol% of samaria. We reveal in a model experiment through a solid solution series of samaria doped ceria epitaxial films that the occurrence of associate defects in the bulk affects the surface charging state of the films to increase the exchange rates. Lastly, the implication of these findings are the design of coatings with tuned oxygen surface exchange by control of bulk associate clusters for future electro-catalytic applications.

  12. FinalReport for completed IPP-0110 and 0110A Projects:"High Energy Ion Technology of Interfacial Thin Film Coatings for Electronic, Optical and Industrial Applications"

    SciTech Connect

    Brown, Ian

    2009-09-01

    The DOE-supported IPP (Initiatives for Proliferation Prevention) Project, IPP-0110, and its accompanying 'add-on project' IPP-0110A, entitled 'High Energy Ion Technology of Interfacial Thin Film Coatings for Electronic, Optical and Industrial Applications' was a collaborative project involving the Lawrence Berkeley National Laboratory (LBNL) as the U.S. DOE lab; the US surface modification company, Phygen, Inc., as the US private company involved; and the High Current Electronics Institute (HCEI) of the Russian Academy of Sciences, Tomsk, Siberia, Russia, as the NIS Institute involved. Regular scientific research progress meetings were held to which personnel came from all participating partners. The meetings were held mostly at the Phygen facilities in Minneapolis, Minnesota (with Phygen as host) with meetings also held at Tomsk, Russia (HCEI as host), and at Berkeley, California (LBNL as host) In this way, good exposure of all researchers to the various different laboratories involved was attained. This report contains the Final Reports (final deliverables) from the Russian Institute, HCEI. The first part is that for IPP-0110A (the 'main part' of the overall project) and the second part is that for the add-on project IPP-0110A. These reports are detailed, and contain all aspects of all the research carried out. The project was successful in that all deliverables as specified in the proposals were successfully developed, tested, and delivered to Phygen. All of the plasma hardware was designed, made and tested at HCEI, and the performance was excellent. Some of the machine and performance parameters were certainly of 'world class'. The goals and requirements of the IPP Project were well satisfied. I would like to express my gratitude to the DOE IPP program for support of this project throughout its entire duration, and for the unparalleled opportunity thereby provided for all of the diverse participants in the project to join in this collaborative research. The

  13. Role of Associated Defects in Oxygen Ion Conduction and Surface Exchange Reaction for Epitaxial Samaria-Doped Ceria Thin Films as Catalytic Coatings.

    PubMed

    Yang, Nan; Shi, Yanuo; Schweiger, Sebastian; Strelcov, Evgheni; Belianinov, Alex; Foglietti, Vittorio; Orgiani, Pasquale; Balestrino, Giuseppe; Kalinin, Sergei V; Rupp, Jennifer L M; Aruta, Carmela

    2016-06-15

    Samaria-doped ceria (SDC) thin films are particularly important for energy and electronic applications such as microsolid oxide fuel cells, electrolyzers, sensors, and memristors. In this paper, we report a comparative study investigating ionic conductivity and surface reactions for well-grown epitaxial SDC films varying the samaria doping concentration. With increasing doping above 20 mol % of samaria, an enhancement in the defect association is observed by Raman spectroscopy. The role of such associated defects on the films̀ oxygen ion transport and exchange is investigated by electrochemical impedance spectroscopy and electrochemical strain microscopy (ESM). The measurements reveal that the ionic transport has a sharp maximum in ionic conductivity and drops in its activation energy down to 0.6 eV for 20 mol % doping. Increasing the doping concentration further up to 40 mol %, it raises the activation energy substantially by a factor of 2. We ascribe the sluggish transport kinetics to the "bulk" ionic-near ordering in case of the heavily doped epitaxial films. Analysis of the ESM first-order reversal curve measurements indicates that these associated defects may have a beneficial role by lowering the activation of the oxygen exchange "surface" reaction for heavily doped 40 mol % of samaria. In a model experiment, through a solid solution series of samaria doped ceria epitaxial films, we reveal that the occurrence of associated defects in the bulk affects the surface charging state of the SDC films to increase the exchange rates. The implication of these findings is the design of coatings with tuned oxygen surface exchange by controlling the bulk associated clusters for future electrocatalytic applications.

  14. Mechanics of Thin Films

    DTIC Science & Technology

    1992-02-06

    S. Hwang, Thermal conductivity of thin films: measurement and microstructural effects, in Thin- film heat transfer, properties and processing, ed...thermal, electrical, optical and magnetic properties . As typical examples we mention microelectronics, optical coatings and multilayers for use in optical...interplay between mechanical properties (elastic moduli), thermal properties (thermal conductivity, thermal expansion coefficient), and optical

  15. Fabrication and characterization of a diluted magnetic semiconducting TM co-doped Al:ZnO (TM=Co, Ni) thin films by sol-gel spin coating method.

    PubMed

    Siddheswaran, R; Mangalaraja, R V; Tijerina, Eduardo P; Menchaca, J-Luis; Meléndrez, M F; Avila, Ricardo E; Jeyanthi, C Esther; Gomez, M E

    2013-04-01

    Effect of transition metal oxides (TM=Co and Ni) co-doping on the crystallinity, surface morphology, grain growth and magnetic properties of nanostructure Al:ZnO thin films has been studied for diluted magnetic semiconductor applications. Al:ZnO thin films were fabricated by sol-gel spin coating on p-type Si (100) substrates. Fabrication of hexagonal wurtzite TM co-doped Al:ZnO thin films having thickness 2μm was successfully achieved. The Raman spectra of the TM co-doped Al:ZnO thin films showed a broad vibrational mode in the range 520-540cm(-1) due to crystal defects created co-doping elements in the ZnO host lattice. Scanning electron microscopy (SEM) revealed that the films are composed of uniform size, polycrystalline dense ZnO particles with defect free, smooth surfaces. The surface roughness was further verified with atomic force microscopy (AFM). The energy dispersive X-ray spectroscopic analysis (EDX) confirmed the stoichiometric compositions of the TM co-doped Al:ZnO films. The magnetic measurements exhibited that the Co, Al:ZnO and Ni, Al:ZnO thin films were ferromagnetic at room temperature.

  16. Biomimetic thin film synthesis

    SciTech Connect

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  17. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

    PubMed Central

    Passos, Helena; Luís, Andreia; Coutinho, João A. P.; Freire, Mara G.

    2016-01-01

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process. PMID:26843320

  18. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems.

    PubMed

    Passos, Helena; Luís, Andreia; Coutinho, João A P; Freire, Mara G

    2016-02-04

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  19. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

    NASA Astrophysics Data System (ADS)

    Passos, Helena; Luís, Andreia; Coutinho, João A. P.; Freire, Mara G.

    2016-02-01

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  20. Actinide recovery using aqueous biphasic extraction: Initial developmental studies

    SciTech Connect

    Chaiko, D.J.; Mensah-Biney, R.; Mertz, C.J.; Rollins, A.N.

    1992-08-01

    Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less.

  1. Biphasic dose response in low level light therapy.

    PubMed

    Huang, Ying-Ying; Chen, Aaron C-H; Carroll, James D; Hamblin, Michael R

    2009-09-01

    The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing cell death and tissue damage has been known for over forty years since the invention of lasers. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial in mainstream medicine. The biochemical mechanisms underlying the positive effects are incompletely understood, and the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light. The so-called Arndt-Schulz curve is frequently used to describe this biphasic dose response. This review will cover the molecular and cellular mechanisms in LLLT, and describe some of our recent results in vitro and in vivo that provide scientific explanations for this biphasic dose response.

  2. Biphasic interaction of Triton detergents with the erythrocyte membrane.

    PubMed Central

    Trägner, D; Csordas, A

    1987-01-01

    Octylphenoxy polyoxyethylene ethers (Triton detergents) interact with the erythrocyte membrane in a biphasic manner, i.e. they stabilize erythrocytes against hypo-osmotic haemolysis at low concentrations (0.0001-0.01%, v/v), but become haemolytic at higher concentrations. This biphasic behaviour was demonstrated with Triton X-114, Triton X-100 and Triton X-102. However, a critical chain length is a prerequisite for the haemolytic effect, because Triton X-45, which differs from the other Tritons only by the shorter chain of the polyoxyethylene residue, does not exhibit this biphasic behaviour, but goes on protecting against osmotic rupture up to saturating concentrations. Even a 1% solution of Triton X-45 does not cause haemolysis. This structural specificity of Triton X-45, namely the lack of haemolysis and efficient stabilization against osmolysis even at higher concentrations of the detergent, is exhibited at 0 degree and 37 degrees C as well as at room temperature. Three conclusions are reached: (i) a critical chain length of the octylphenoxy polyoxyethylene ethers is required for the haemolytic effect; (ii) the different structural requirements would suggest that different mechanisms are responsible for the haemolytic and the stabilizing effect of amphiphilic substances; (iii) the results suggest that haemolysis is not caused simply by dissolution of the membrane by the detergent but is a rather more specific process. PMID:3446180

  3. Biphasic Dose Response in Low Level Light Therapy

    PubMed Central

    Huang, Ying-Ying; Chen, Aaron C.-H.; Carroll, James D.; Hamblin, Michael R.

    2009-01-01

    The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing cell death and tissue damage has been known for over forty years since the invention of lasers. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial in mainstream medicine. The biochemical mechanisms underlying the positive effects are incompletely understood, and the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light. The so-called Arndt-Schulz curve is frequently used to describe this biphasic dose response. This review will cover the molecular and cellular mechanisms in LLLT, and describe some of our recent results in vitro and in vivo that provide scientific explanations for this biphasic dose response. PMID:20011653

  4. The enhancement of photo-thermo-electric conversion in tilted Bi2Sr2Co2O(y) thin films through coating a layer of single-wall carbon nanotubes light absorber.

    PubMed

    Wang, Shufang; Bai, Zilong; Yan, Guoying; Zhang, Hongrui; Wang, Jianglong; Yu, Wei; Fu, Guangsheng

    2013-07-29

    Light-induced transverse thermoelectric effect has been investigated in c-axis tilted Bi(2)Sr(2)Co(2)O(y) thin films coated with a single-wall carbon nanotubes light absorption layer. Open-circuit voltage signals were detected when the sample surface was irradiated by different lasers with wavelengths ranging from ultraviolet to near-infrared and the voltage sensitivity was enhanced as a result of the increased light absorption at the carbon nanotubes layer. Moreover, the enhancement degree was found to be dependent on the laser wavelength as well as the absorption coating size. This work opens up new strategy toward the practical applications of layered cobaltites in photo-thermo-electric conversion devices.

  5. Improved Photovoltaic Characteristics and Grain Boundary Potentials of CuIn0.7Ga0.3Se2 Thin Films Spin-Coated by Na-Dissolved Nontoxic Precursor Solution.

    PubMed

    Choi, Ik Jin; Jang, Jin Woo; Mohanty, Bhaskar Chandra; Lee, Seung Min; Cho, Yong Soo

    2016-07-13

    This work introduces the incorporation of Na into the nontoxic precursor solution of CIGS to improve photovoltaic cell performance with the optimized benefits of Na. The extensive incorporation range of 0.05 to 0.5 mol % Na is used for the simple spin-coating process of high quality absorber thin films. A cell efficiency of ∼8.21%, which corresponds to an improvement of ∼10.2% compared to the reference sample, is achieved for the 0.25 mol % Na sample with enhanced open-circuit voltage and fill factor. The improvement was further analyzed as related to InCu defects and grain boundary potentials.

  6. Regeneration of a goat femoral head using a tissue-specific, biphasic scaffold fabricated with CAD/CAM technology.

    PubMed

    Ding, Chunming; Qiao, Zhiguang; Jiang, Wenbo; Li, Haowei; Wei, Jianhe; Zhou, Guangdong; Dai, Kerong

    2013-09-01

    Tissue engineering is considered as a promising approach for the regeneration of biological joint theoretically and thus provides a potential treatment option for advanced osteoarthritis. However, no significant progresses so far have been made in regenerating biological joint. In this study, a biphasic scaffold, which was consisted of polylactic acid-coated polyglycolic acid (PGA/PLA) scaffold and poly-ε-caprolactone/hydroxyapatite (PCL/HA) scaffold, was designed and used for regeneration of goat femoral head. The content of PLA and HA was optimized to a proper ratio, thus the scaffolds could achieve appropriate stiffness which was more conducive to articular cartilage and bone regeneration respectively. Furthermore, computer-aided design and manufacturing (CAD/CAM) technology was employed to fabricate the biphasic scaffolds into the desired shape and structure. The biphasic scaffolds with fine cell biocompatibility matched perfectly. Chondrocytes and bone marrow stromal cells (BMSCs) were seeded into the scaffolds for cartilage and bone regeneration respectively. After 10 weeks of implantation in nude mice subcutaneously, the cell-scaffold constructs successfully regenerated goat femoral heads. The regenerated femoral heads presented a precise appearance in shape and size similar to that of native goat femoral heads with a smooth, continuous, avascular, and homogeneous cartilage layer on the surface and stiff bone-like tissue in the microchannels of PCL/HA scaffold. Additionally, histological examination of the regenerated cartilage and bone showed typical histological structures and biophysical properties similar to that of native ones with specific matrix deposition and a well-integrated osteochondral interface. The strategy established in the study provides a promising approach for regenerating a biological joint which could be used to reconstruct the impaired joint.

  7. Electrostatic bonding of thin (cycle sine 3 mil) 7070 cover glass to Ta2O5 AR-coated thin (cycle sine 2 mil) silicon wafers and solar cells

    NASA Technical Reports Server (NTRS)

    Egelkrout, D. W.

    1981-01-01

    Electrostatic bonding of thin cover glass to thin solar cells was researched. Silicon solar cells, wafers, and Corning 7070 glass of from about 0.002" to about 0.003" in thickness were used in the investigation to establish optimum parameters for producing mechanically acceptable bonds while minimizing thermal stresses and resultant solar cell electrical parameter degradation.

  8. The Effect of Covalently Immobilized FGF-2 on Biphasic Calcium Phosphate Bone Substitute on Enhanced Biological Compatibility and Activity.

    PubMed

    Moon, Kyung-Suk; Choi, Eun-Joo; Oh, Seunghan; Kim, Sungtae

    2015-01-01

    The purpose of this research was to covalently graft fibroblast growth factor 2 (FGF-2) onto biphasic calcium phosphate (BCP) via a bifunctional cross-linker technique and to estimate the optimal dose of FGF-2 resulting in the best osteogenic differentiation of human mesenchymal stem cells (hMSCs). SEM observation revealed that the surface of the 100 ng FGF-2 coated BCP was completely covered with the nanoparticles expected to be from the silane coupling agent. XRD, FT-IR, and XPS analysis showed that silane treatment, bifunctional cross-linker coating, and FGF-2 covalent grafts were conducted successfully without deforming the crystalline structure of BCP. An MTT assay demonstrated that FGF-2 coated BCP had good biocompatibility, regardless of the concentration of FGF-2, after 24 or 48 h of incubation. An alkaline phosphatase (ALP) activity assay (14 days of incubation) and the ALP gene expression level of real-time PCR analysis (7 days of incubation) revealed that 50, 100, and 200 ng FGF-2 coated BCP induced the highest activities among all experimental groups and control group (P < 0.05). Thus, low concentrations of FGF-2 facilitated excellent osteogenesis and were effective at enhancing osteogenic potential. Also, the bifunctional cross-linker technique is expected to be a more feasible way to induce osteogenic differentiation while minimizing the risk of FGF-2 overdose.

  9. Optical thin film devices

    NASA Astrophysics Data System (ADS)

    Mao, Shuzheng

    1991-11-01

    Thin film devices are applied to almost all modern scientific instruments, and these devices, especially optical thin film devices, play an essential role in the performances of the instruments, therefore, they are attracting more and more attention. Now there are numerous kinds of thin film devices and their applications are very diversified. The 300-page book, 'Thin Film Device and Applications,' by Prof. K. L. Chopra gives some general ideas, and my paper also outlines the designs, fabrication, and applications of some optical thin film devices made in my laboratory. Optical thin film devices have been greatly developed in the recent decades. Prof. A. Thelan has given a number of papers on the theory and techniques, Prof. H. A. Macleod's book, 'Thin Film Optical Filters,' has concisely concluded the important concepts of optical thin film devices, and Prof. J. A. Dobrowobski has proposed many successful designs for optical thin film devices. Recently, fully-automatic plants make it easier to produce thin film devices with various spectrum requirements, and some companies, such as Balzers, Leybold AG, Satis Vacuum AG, etc., have manufactured such kinds of coating plants for research or mass-production, and the successful example is the production of multilayer antireflection coatings with high stability and reproducibility. Therefore, it could be said that the design of optical thin film devices and coating plants is quite mature. However, we cannot expect that every problem has been solved, the R&D work still continues, the competition still continues, and new design concepts, new techniques, and new film materials are continually developed. Meanwhile, the high-price of fully-automatic coating plants makes unpopular, and automatic design of coating stacks is only the technique for optimizing the manual design according to the physical concepts and experience, in addition, not only the optical system, but also working environment should be taken into account when

  10. A biphasic scaffold design combined with cell sheet technology for simultaneous regeneration of alveolar bone/periodontal ligament complex.

    PubMed

    Vaquette, Cédryck; Fan, Wei; Xiao, Yin; Hamlet, Stephen; Hutmacher, Dietmar W; Ivanovski, Saso

    2012-08-01

    This study describes the design of a biphasic scaffold composed of a Fused Deposition Modeling scaffold (bone compartment) and an electrospun membrane (periodontal compartment) for periodontal regeneration. In order to achieve simultaneous alveolar bone and periodontal ligament regeneration a cell-based strategy was carried out by combining osteoblast culture in the bone compartment and placement of multiple periodontal ligament (PDL) cell sheets on the electrospun membrane. In vitro data showed that the osteoblasts formed mineralized matrix in the bone compartment after 21 days in culture and that the PDL cell sheet harvesting did not induce significant cell death. The cell-seeded biphasic scaffolds were placed onto a dentin block and implanted for 8 weeks in an athymic rat subcutaneous model. The scaffolds were analyzed by μCT, immunohistochemistry and histology. In the bone compartment, a more intense ALP staining was obtained following seeding with osteoblasts, confirming the μCT results which showed higher mineralization density for these scaffolds. A thin mineralized cementum-like tissue was deposited on the dentin surface for the scaffolds incorporating the multiple PDL cell sheets, as observed by H&E and Azan staining. These scaffolds also demonstrated better attachment onto the dentin surface compared to no attachment when no cell sheets were used. In addition, immunohistochemistry revealed the presence of CEMP1 protein at the interface with the dentine. These results demonstrated that the combination of multiple PDL cell sheets and a biphasic scaffold allows the simultaneous delivery of the cells necessary for in vivo regeneration of alveolar bone, periodontal ligament and cementum.

  11. Effects of Concentration of Precursor and Annealing Temperature on the Optical Properties of Nanostructured Al- doped Zinc Oxide (AZO) Thin films Prepared by Sol-Gel Spin Coating Technique

    NASA Astrophysics Data System (ADS)

    Yusuf, Gbadebo; Awodugba, Ayodeji; Raimi, Adepoju; Efunwole, Hezekiah; Familusi, Timothy

    2013-03-01

    This work investigates the effects of concentration of precursor and annealing temperature on the optical properties of nanostructured Al-doped (AZO) zinc oxide thin films prepared by sol-gel spin coating technique. The sols were prepared using concentration of zinc acetate dehydrate which was varied between 0.1 and 1.4 mole/liter. Aluminium chloride was used as dopant while the annealing temperature of 400° to 650° was chosen. The results show that the concentration between 0.3 to 0.6 moles/liter zinc acetate dehydrate in solution resulted in good thin films with high preferential c-axis orientation and optical transmission reveal a good transmittance within the visible wavelength spectrum region while the concentrations that fall outside this range did not yield films with good c-axis orientation. The films deposited at annealing temperatures 500° and 650° showed surface structures much smaller than 400°. The Spin coating technique creates ZnO films with potential for application as transparent electrodes in optoelectronic devices such as solar cell. The Authors would like to Acknowledge the encouragement and financial support from the Management of Osun state Polytechnic, Iree.

  12. Improved specimen coating technique for scanning electron microscope observation of decomposer microorganisms.

    PubMed

    Draggan, S

    1976-02-01

    Sputter coating of leaf litter microbe samples provides scanning electron microscope images with greater information content than either vacuum evaporation of thin metal coatings or tissue conductance.

  13. In situ measurement of cure, latex coalescence and end-use properties in thin film coatings using frequency dependent impedance sensing

    SciTech Connect

    Kranbuehl, D.E.

    1993-12-31

    As in situ frequency dependent impedance sensor (FDIMS) has been successfully used to monitor cure and buildup in end use properties of coatings. The planar microsensor is able to make continuous uninterrupted measurements of the resin while it cures as a coating with only one side exposed. It is able to monitor reaction onset, reaction rate, viscosity, buildup in hardness, reaction completion and related processes such as latex coalescence and evolution of volatiles. Effects of storage, temperature, humidity, thickness and variations in composition on the cure process can also be detected. The sensor monitors the changes in the rate of translational motion of ions and rotational motion of dipoles through frequency dependent complex impedance measurements. In this report the ability of the sensor to monitor the effects of the environmental conditions such as temperature and humidity, as well as coating formulation differences due to pigments, on the cure process is reported. The ability of the FDIMS sensor to monitor the extent to which a second coating can soften the initial coating will be discussed. The ability of the FDIMS sensors to monitor the extent to which water can diffuse into the coating will also be described.

  14. Effects of Precursor Concentration on Structural and Optical Properties of ZnO Thin Films Grown on Muscovite Mica Substrates by Sol-Gel Spin-Coating.

    PubMed

    Kim, Younggyu; Leem, Jae-Young

    2016-05-01

    The structural and optical properties of the ZnO thin films grown on mica substrates for different precursor concentrations were investigated. The surface morphologies of all the samples indicated that they consisted of granular structures with spherical nano-sized crystallites. The thickness of the ZnO thin films increased significantly and the optical band gap exhibited a blue shift with an increase in the precursor concentration. It is remarkable that the highest I(NBE)/I(DLE) ratio was observed for the ZnO thin film with 0.8 M precursor concentration, even though cracks formed on the surface of this film.

  15. Effect of annealing treatment on electrical and optical properties of Nb doped TiO2 thin films as a TCO prepared by sol-gel spin coating method

    NASA Astrophysics Data System (ADS)

    Fallah, Milad; Zamani-Meymian, Mohammad-Reza; Rahimi, Rahmatollah; Rabbani, Mahboubeh

    2014-10-01

    Anatase niobium doped TiO2 thin films (Ti0.94Nb0.06O2) were prepared on quartz substrates by sol-gel spin coating technique and various initial concentrations ([Ti + Nb] in the solution) of 0.1 M and 0.4 M. All the films dried at 100 °C and then the annealing treatment performed by three different procedures. The influence of different annealing processes and total metal concentrations was studied on crystallinity, transparency, conductivity and morphology of thin films by XRD, EDX, FT-IR and UV-vis transmittance spectroscopy, four point probe, AFM and SEM images. It was found that two-step annealing procedure under vacuum is a more proper way to increase the conductivity of TNO thin films compared to one-step annealing process. Two-step method exhibited the minimum resistivity of 4.4 Ω cm and the transparency of about 50% in the visible region with 36 nm thickness.

  16. Development of modified-release tablets of zolpidem tartrate by biphasic quick/slow delivery system.

    PubMed

    Mahapatra, Anjan Kumar; Sameeraja, N H; Murthy, P N

    2015-06-01

    Zolpidem tartrate is a non-benzodiazepine analogue of imidazopyridine of sedative and hypnotic category. It has a short half-life with usual dosage regimen being 5 mg, two times a day, or 10 mg, once daily. The duration of action is considered too short in certain circumstances. Thus, it is desirable to lengthen the duration of action. The formulation design was implemented by preparing extended-release tablets of zolpidem tartrate using the biphasic delivery system technology, where sodium starch glycolate acts as a superdisintegrant in immediate-release part and hydroxypropyl methyl cellulose as a release retarding agent in extended-release core. Tablets were prepared by direct compression. Both the core and the coat contained the drug. The pre-compression blends were evaluated for angle of repose, bulk density, and compressibility index. The tablets were evaluated for thickness, hardness, weight variation test, friability, and in vitro release studies. No interaction was observed between zolpidem tartrate and excipients from the Fourier transform infrared spectroscopy and differential scanning calorimetry analysis. The results of all the formulations prepared were compared with reference product Stilnoct®. Optimized formulations showed release patterns that match the United States Pharmacopeia (USP) guidelines for zolpidem tartrate extended-release tablets. The mechanism of drug release was studied using different mathematical models, and the optimized formulation has shown Fickian diffusion. Accelerated stability studies were performed on the optimized formulation.

  17. Cell–material interactions on biphasic polyurethane matrix

    PubMed Central

    Dicesare, Patrick; Fox, Wade M.; Hill, Michael J.; Krishnan, G. Rajesh; Yang, Shuying; Sarkar, Debanjan

    2013-01-01

    Cell–matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell–matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

  18. Biphasic patterns of diversification and the emergence of modules

    PubMed Central

    Mittenthal, Jay; Caetano-Anollés, Derek; Caetano-Anollés, Gustavo

    2012-01-01

    The intricate molecular and cellular structure of organisms converts energy to work, which builds and maintains structure. Evolving structure implements modules, in which parts are tightly linked. Each module performs characteristic functions. In this work we propose that a module can emerge through two phases of diversification of parts. Early in the first phase of this biphasic pattern, the parts have weak linkage—they interact weakly and associate variously. The parts diversify and compete. Under selection for performance, interactions among the parts increasingly constrain their structure and associations. As many variants are eliminated, parts self-organize into modules with tight linkage. Linkage may increase in response to exogenous stresses as well as endogenous processes. In the second phase of diversification, variants of the module and its functions evolve and become new parts for a new cycle of generation of higher-level modules. This linkage hypothesis can interpret biphasic patterns in the diversification of protein domain structure, RNA and protein shapes, and networks in metabolism, codes, and embryos, and can explain hierarchical levels of structural organization that are widespread in biology. PMID:22891076

  19. Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

    PubMed

    Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

    2014-04-01

    Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca(2+) release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

  20. Biphasic behavior of energy in a stepped chain

    NASA Astrophysics Data System (ADS)

    Ping-Jian, Wang; Ai-Xiang, He; Zhong-Hai, Lin; Guang-Fen, Wei; Yan-Li, Liu

    2016-06-01

    The impact energy decay in a step-up chain containing two sections is numerically studied. There is a marked biphasic behavior of energy decay in the first section. Two sections close to the interface are in compression state. The degree of compression of the first section first decreases and becomes weakest at “crossing” time of biphasic behavior of energy, then increases. The further calculations provide the dependence of the character time on mass ratio (m 1/m 2), where m 1 and m 2 are the particle mass in the first and second section respectively. The bigger the α (α = [(Ωm 1 - m 2)/(Ωm 1 + m 2)]2 with Ω = 1.345), the bigger the energy ratio is. The multipulse structure restricts the transport of energy. Project supported by the National Natural Science Foundation of China (Grant Nos. 61174007 and 61307041) and the Natural Science Foundation of Shandong Province, China (Grant No. ZR2013AL014).

  1. Biphasic cardiovascular and respiratory effects induced by β-citronellol.

    PubMed

    Ribeiro-Filho, Helder Veras; de Souza Silva, Camila Meirelles; de Siqueira, Rodrigo JoséBezerra; Lahlou, Saad; dos Santos, Armênio Aguiar; Magalhães, Pedro Jorge Caldas

    2016-03-15

    β-Citronellol is a monoterpene found in the essential oil of various plants with antihypertensive properties. In fact, β-citronellol possesses hypotensive actions due to its vasodilator abilities. Here we aimed to show that β-citronellol recruits airway sensory neural circuitry to evoke cardiorespiratory effects. In anesthetized rats, intravenous injection of β-citronellol caused biphasic hypotension, bradycardia and apnea. Bilateral vagotomy, perivagal capsaicin treatment or injection into the left ventricle abolished first rapid phase (named P1) but not delayed phase P2 of the β-citronellol effects. P1 persisted after pretreatment with capsazepine, ondansetron, HC-030031 or suramin. Suramin abolished P2 of apnea. In awake rats, β-citronellol induced biphasic hypotension and bradycardia being P1 abolished by methylatropine. In vitro, β-citronellol inhibited spontaneous or electrically-evoked contractions of rat isolated right or left atrium, respectively, and fully relaxed sustained contractions of phenylephrine in mesenteric artery rings. In conclusion, chemosensitive pulmonary vagal afferent fibers appear to mediate the cardiovascular and respiratory effects of β-citronellol. The transduction mechanism in P1 seems not to involve the activation of transient receptor potential vanilloid subtype 1 (TRPV1), transient receptor potential ankyrin subtype 1 (TRPA1), purinergic (P2X) or 5-HT3 receptors located on airways sensory nerves. P2 of hypotension and bradycardia seems resulting from a cardioinhibitory and vasodilatory effect of β-citronellol and the apnea from a purinergic signaling.

  2. Biphasic Affinity Chromatographic Approach for Deep Tyrosine Phosphoproteome Analysis.

    PubMed

    Deng, Zhenzhen; Dong, Mingming; Wang, Yan; Dong, Jing; Li, Shawn S-C; Zou, Hanfa; Ye, Mingliang

    2017-02-21

    Tyrosine phosphorylation (pTyr) is important for normal physiology and implicated in many human diseases, particularly cancer. Identification of pTyr sites is critical to dissecting signaling pathways and understanding disease pathologies. However, compared with serine/threonine phosphorylation (pSer/pThr), the analysis of pTyr at the proteome level is more challenging due to its low abundance. Here, we developed a biphasic affinity chromatographic approach where Src SH2 superbinder was coupled with NeutrAvidin affinity chromatography, for tyrosine phosphoproteome analysis. With the use of competitive elution agent biotin-pYEEI, this strategy can distinguish high-affinity phosphotyrosyl peptides from low-affinity ones, while the excess competitive agent is readily removed by using NeutrAvidin agarose resin in an integrated tip system. The excellent performance of this system was demonstrated by analyzing tyrosine phosphoproteome of Jurkat cells from which 3,480 unique pTyr sites were identified. The biphasic affinity chromatography method for deep Tyr phosphoproteome analysis is rapid, sensitive, robust, and cost-effective. It is widely applicable to the global analysis of the tyrosine phosphoproteome associated with tyrosine kinase signal transduction.

  3. Enhanced optical and electrical properties of boron-doped zinc-oxide thin films prepared by using the sol-gel dip-coating method

    NASA Astrophysics Data System (ADS)

    Lee, Sang-heon; Kim, MinSu; Jung, YuJin; Jung, Jae Hak; Kim, Soaram; Leem, Jae-Young; Kim, Howoon

    2013-11-01

    Undoped ZnO and B-dopoed ZnO (BZO) thin films with 0 to 2.5 at.% B were prepared by using sol-gel synthesis. Their optical and electrical properties and surface morphology were investigated using scanning electron microscopy, photoluminescence (PL), and van der Pauw Hall-effect measurements. All of the thin films were deposited appropriately onto quartz substrates; they exhibited a fibrous root morphology, with structures that changed in size with increasing B concentration. The PL spectra showed near-band-edge (NBE) emissions and deep-level emissions (DLE). The NBE emission and the DLE for the BZO thin films were more blue-shifted than those for the undoped ZnO thin film, and the blue shift increased the efficiency of the NBE emission of the BZO thin films. The Hall-effect data suggested that B doping also improved the electrical properties, such as the carrier concentration, Hall mobility, and resistivity, of the thin films. The resistivity and the Hall mobility decreased with increasing B concentration and were inversely proportional to the carrier concentration.

  4. Thin films of calcium phosphate and titanium dioxide by a sol-gel route: a new method for coating medical implants.

    PubMed

    Piveteau, L D; Girona, M I; Schlapbach, L; Barboux, P; Boilot, J P; Gasser, B

    1999-03-01

    Titanium is a commonly used biomaterial for dental and orthopaedic applications. To increase its ability to bond with bone, some attempts were made to coat its surface with calcium phosphate (CaP). This paper describes a new type of coating. Instead of a pure CaP layer, a mixing of titanium dioxide (TIO2) and CaP is fabricated and deposited as a coating. These layers are deposited by a sol-gel route on pure titanium substrates using various pre-treatments. The method consists of mixing a solution of tetrabutyl ortho-titanate or a sol of titanium dioxide with a solution of calcium nitrate and phosphorous esters. This composite is deposited on to commercially pure titanium plates, mechanically polished or blasted with pure crystalline aluminum oxide, using the spin-coating technique. These coatings are then fired at 650 or 850 degrees C for various times. The samples are characterized by X-ray diffraction for their crystallinity, X-ray photoelectron spectroscopy for their surface chemical composition and scanning electron microscopy for their topography. Samples treated at 850 degrees C present a well-pronounced crystallinity, and a high chemical purity at the surface. The topography is strongly related to the viscosity of the precursor and the substrate pre-treatment. Possibilities to structure the outermost layer are presented.

  5. In vivo implantation of porous titanium alloy implants coated with magnesium-doped octacalcium phosphate and hydroxyapatite thin films using pulsed laser depostion.

    PubMed

    Mróz, Waldemar; Budner, Bogusław; Syroka, Renata; Niedzielski, Kryspin; Golański, Grzegorz; Slósarczyk, Anna; Schwarze, Dieter; Douglas, Timothy E L

    2015-01-01

    The use of porous titanium-based implant materials for bone contact has been gaining ground in recent years. Selective laser melting (SLM) is a rapid prototyping method by which porous implants with highly defined external dimensions and internal architecture can be produced. The coating of porous implants produced by SLM with ceramic layers based on calcium phosphate (CaP) remains relatively unexplored, as does the doping of such coatings with magnesium (Mg) to promote bone formation. In this study, Mg-doped coatings of the CaP types octacalcium phosphate and hydroxyapatite (HA) were deposited on such porous implants using the pulsed laser deposition method. The coated implants were subsequently implanted in a rabbit femoral defect model for 6 months. Uncoated implants served as a reference material. Bone-implant contact and bone volume in the region of interest were evaluated by histopathological techniques using a tri-chromatographic Masson-Goldner staining method and by microcomputed tomography (µCT) analysis of the volume of interest in the vicinity of implants. Histopathological analysis revealed that all implant types integrated directly with surrounding bone with ingrowth of newly formed bone into the pores of the implants. Biocompatibility of all implant types was demonstrated by the absence of inflammatory infiltration by mononuclear cells (lymphocytes), neutrophils, and eosinophils. No osteoclastic or foreign body reaction was observed in the vicinity of the implants. µCT analysis revealed a significant increase in bone volume for implants coated with Mg-doped HA compared to uncoated implants.

  6. An augmented Lagrangian finite element formulation for 3D contact of biphasic tissues.

    PubMed

    Guo, Hongqiang; Spilker, Robert L

    2014-01-01

    Biphasic contact analysis is essential to obtain a complete understanding of soft tissue biomechanics, and the importance of physiological structure on the joint biomechanics has long been recognised; however, up to date, there are no successful developments of biphasic finite element contact analysis for three-dimensional (3D) geometries of physiological joints. The aim of this study was to develop a finite element formulation for biphasic contact of 3D physiological joints. The augmented Lagrangian method was used to enforce the continuity of contact traction and fluid pressure across the contact interface. The biphasic contact method was implemented in the commercial software COMSOL Multiphysics 4.2(®) (COMSOL, Inc., Burlington, MA). The accuracy of the implementation was verified using 3D biphasic contact problems, including indentation with a flat-ended indenter and contact of glenohumeral cartilage layers. The ability of the method to model multibody biphasic contact of physiological joints was proved by a 3D knee model. The 3D biphasic finite element contact method developed in this study can be used to study the biphasic behaviours of the physiological joints.

  7. Evenly distributed thin-film Ag coating on stainless plate by tricomponent Ag/silicate/PU with antimicrobial and biocompatible properties.

    PubMed

    Huang, Yi-Hsiu; Chen, Mark Hung-Chih; Lee, Bing-Heng; Hsieh, Kuo-Huang; Tu, Yuan-Kun; Lin, Jiang-Jen; Chang, Chih-Hao

    2014-11-26

    A tricomponent nanohybrid dispersion in water comprising silver nanoparticles (AgNP), nanometer-thick silicate platelets (NSP), and water-based polyurethane (PU) was developed for surface coating on orthopedic metal plates. The previously developed AgNP-on-NSP nanohybrid was homogeneously blended into a selected waterborne PU dispersion at varied weight ratios from 1/0.1 to 1/10 (w/w). PU was used to adhere the Ag nanohybrid to the metal surface. The resultant dispersions were analyzed and found to contain AgNP 2-18 nm in diameter and characterized by using UV absorption and TEM micrograph. The subsequent coating of AgNP/NSP-PU dispersion generated a film of 1.5 μm thickness on the metal plate surface, further characterized by an energy dispersive spectroscope (EDS) to show the homogeneous distribution of Ag, Si, and C elements on the metal plates. The surface antimicrobial efficacy was proven for the coating composition of AgNP/NSP to PU ranging from 1/1 to 1/5 by weight ratio but irrelevant to the thickness of the coated materials. The metal plate coated with the high Ag content at 1/1 (w/w) ratio was shown to have very low cytotoxicity toward the contacted mammal fibroblasts. Overall, the optimized tricomponent Ag/silicate/PU in water dispersion from 1/2 to 1/3 (w/w) could generate a stable film on a metal surface exhibiting both antimicrobial and biocompatible properties. The facile coating technique of the AgNP/NSP in waterborne PU is proven to be viable for fabricating infection- and cytotoxicity-free medical devices.

  8. A flow reactor setup for photochemistry of biphasic gas/liquid reactions

    PubMed Central

    Schachtner, Josef; Bayer, Patrick

    2016-01-01

    Summary A home-built microreactor system for light-mediated biphasic gas/liquid reactions was assembled from simple commercial components. This paper describes in full detail the nature and function of the required building elements, the assembly of parts, and the tuning and interdependencies of the most important reactor and reaction parameters. Unlike many commercial thin-film and microchannel reactors, the described set-up operates residence times of up to 30 min which cover the typical rates of many organic reactions. The tubular microreactor was successfully applied to the photooxygenation of hydrocarbons (Schenck ene reaction). Major emphasis was laid on the realization of a constant and highly reproducible gas/liquid slug flow and the effective illumination by an appropriate light source. The optimized set of conditions enabled the shortening of reaction times by more than 99% with equal chemoselectivities. The modular home-made flow reactor can serve as a prototype model for the continuous operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories. PMID:27829887

  9. A boundary-integral representation for biphasic mixture theory, with application to the post-capillary glycocalyx

    PubMed Central

    Sumets, P. P.; Cater, J. E.; Long, D. S.; Clarke, R. J.

    2015-01-01

    We describe a new boundary-integral representation for biphasic mixture theory, which allows us to efficiently solve certain elastohydrodynamic–mobility problems using boundary element methods. We apply this formulation to model the motion of a rigid particle through a microtube which has non-uniform wall shape, is filled with a viscous Newtonian fluid, and is lined with a thin poroelastic layer. This is relevant to scenarios such as the transport of small rigid cells (such as neutrophils) through microvessels that are lined with an endothelial glycocalyx layer (EGL). In this context, we examine the impact of geometry upon some recently reported phenomena, including the creation of viscous eddies, fluid flux into the EGL, as well as the role of the EGL in transmitting mechanical signals to the underlying endothelial cells. PMID:26345494

  10. Characterization of ZnO thin films grown on different p-Si substrate elaborated by solgel spin-coating method

    SciTech Connect

    Chebil, W.; Fouzri, A.; Fargi, A.; Azeza, B.; Zaaboub, Z.; and others

    2015-10-15

    Highlights: • High quality ZnO thin films grown on different p-Si substrates were successful obtained by sol–gel process. • PL measurement revealed that ZnO thin film grown on porous Si has the better optical quality. • I–V characteristics for all heterojunctions exhibit successful diode formation. • The diode ZnO/PSi shows a better photovoltaic effect under illumination with a maximum {sub Voc} of 0.2 V. - Abstract: In this study, ZnO thin films are deposited by sol–gel technique on p-type crystalline silicon (Si) with [100] orientation, etched silicon and porous silicon. The structural analyses showed that the obtained thin films were polycrystalline with a hexagonal wurtzite structure and preferentially oriented along the c-axis direction. Morphological study revealed the presence of rounded and facetted grains irregularly distributed on the surface of all samples. PL spectra at room temperature revealed that ZnO thin film grown on porous Si has a strong UV emission with low defects in the visible region comparing with ZnO grown on plat Si and etched Si surface. The heterojunction parameters were evaluated from the (I–V) under dark and illumination at room temperature. The ideality factor, barrier height and series resistance of heterojunction grown on different p-Si substrates are determined by using different methods. Best electrical properties are obtained for ZnO layer deposited on porous silicon.

  11. Thin Film Solid Lubricant Development

    NASA Technical Reports Server (NTRS)

    Benoy, Patricia A.

    1997-01-01

    Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

  12. Oscillatory Motion of a Bi-Phasic Slug in a Teflon Reactor

    NASA Astrophysics Data System (ADS)

    Abolhasani, Milad; Jensen, Klavs

    2015-11-01

    Bi-phasic physical/chemical processes require transfer of solute/reagent molecules across the interface. Continuous multi-phase flow approaches (using gas as the continuous phase), usually fail in providing sufficient interfacial area for transfer of molecules between the aqueous and organic phases. In continuous segmented flow platforms (with a fluorinated polymer-based reactor), the higher surface tension of the aqueous phase compared to the organic phase of a bi-phasic slug, in combination with the low surface energy of the reactor wall result in a more facile motion of the aqueous phase. Thus, upon applying a pressure gradient across the bi-phasic slug, the aqueous phase of the slug moves through the organic phase and leads the bi-phasic slug, thereby limiting the available interfacial area for the bi-phasic mass transfer only to the semi-spherical interface between the two phases. Disrupting the quasi-equilibrium state of the bi-phasic slug through reversing the pressure gradient across the bi-phasic slug causes the aqueous phase to move back through the organic phase. In this work, we experimentally investigate the dynamics of periodic alteration of the pressure gradient across a bi-phasic slug, and characterize the resulting enhanced interfacial area on the bi-phasic mass transfer rate. We demonstrate the enhanced mass transfer rate of the oscillatory flow strategy compared to the continuous multi-phase approach using bi-phasic Pd catalyzed carbon-carbon and carbon-nitrogen cross coupling reactions. NSERC Postdoctoral Fellowship, Novartis Center for Continuous Manufacturing.

  13. Bone response to titanium implants coated with thin sputtered HA film subject to hydrothermal treatment and implanted in the canine mandible.

    PubMed

    Ozeki, K; Okuyama, Y; Fukui, Y; Aoki, H

    2006-01-01

    Hydroxyapatite (HA) was coated onto titanium implants using radio frequency magnetron sputtering. The HA films were crystallized in an autoclave tube using low temperature hydrothermal treatment. The average film thickness on the implant was 1.1 microm. HA-coated and pure-titanium implants were inserted into canine mandibles for up to 24 weeks. Forty-eight implants were placed in eight beagles. After 2, 4, 12 and 24 weeks, implants were retrieved and prepared for histological observation, and the HA film thickness was determined using energy-dispersive X-ray spectroscopy. Light microscopy revealed that, after two weeks, the bone response to the HA-coated implants was much better than to the pure titanium implants, and osteoblasts were observed at the bone-implant interface. After four weeks, the screw threads of the HA-coated implants were almost completely covered with bone. The HA film thickness rapidly decreased up to four weeks of implantation, then gently decreased, reaching 0.40+/-0.03 microm at the upper region of the implant after 12 weeks. That indicates that about 80% of the HA film had dissolved after 12 weeks of implantation. The rate of decrease in the HA film thickness was greater with increasing implant depth.

  14. Thin coatings based on ZnO@C18-usnic acid nanoparticles prepared by MAPLE inhibit the development of Salmonella enterica early biofilm growth

    NASA Astrophysics Data System (ADS)

    Stan, Miruna Silvia; Constanda, Sabrina; Grumezescu, Valentina; Andronescu, Ecaterina; Ene, Ana Maria; Holban, Alina Maria; Vasile, Bogdan Stefan; Mogoantă, Laurenţiu; Bălşeanu, Tudor-Adrian; Mogoşanu, George Dan; Socol, Gabriel; Grumezescu, Alexandru Mihai; Dinischiotu, Anca; Lazar, Veronica; Chifiriuc, Mariana Carmen

    2016-06-01

    The aim of this study was to develop a nanostructured bioactive surface based on zinc oxide, sodium stearate (C18) and usnic acid (UA) exhibiting harmless effects with respect to the human cells, but with a significant antimicrobial effect, limiting the attachment and biofilm formation of food pathogens. ZnO nanoparticles were synthesized by sol-gel method and functionalized with C18 and UA. The coatings were fabricated by matrix assisted pulsed laser evaporation technique (MAPLE) and further characterized by TEM, SEM, SAED, XRD and IRM. The biological characterization of the prepared coatings consisted in cytotoxicity and antimicrobial assays. The cytotoxicity of ZnO@C18 and ZnO@C18-UA films was evaluated with respect to the human skin fibroblasts (CCD 1070SK cell line) by phase contrast microscopy, MTT assay and nitric oxide (NO) release. The covered surfaces exhibited a decreased cell attachment, effect which was more pronounced in the presence of UA as shown by purple formazan staining of adhered cells. The unattached fibroblasts remained viable after 24 h in the culture media as it was revealed by their morphology analysis and NO level which were similar to uncovered slides. The quantitative microbiological assays results have demonstrated that the bioactive coatings have significantly inhibited the adherence and biofilm formation of Salmonella enterica. The obtained results recommend these materials as efficient approaches in developing anti-adherent coatings for various industrial, medical and food processing applications.

  15. High-side Digitally Current Controlled Biphasic Bipolar Microstimulator

    PubMed Central

    Hanson, Timothy L.; Ómarsson, Björn; O'Doherty, Joseph E.; Peikon, Ian D.; Lebedev, Mikhail; Nicolelis, Miguel AL.

    2012-01-01

    Electrical stimulation of nervous tissue has been extensively used as both a tool in experimental neuroscience research and as a method for restoring of neural functions in patients suffering from sensory and motor disabilities. In the central nervous system, intracortical microstimulation (ICMS) has been shown to be an effective method for inducing or biasing perception, including visual and tactile sensation. ICMS also holds promise for enabling brain-machine-brain interfaces (BMBIs) by directly writing information into the brain. Here we detail the design of a high-side, digitally current-controlled biphasic, bipolar microstimulator, and describe the validation of the device in vivo. As many applications of this technique, including BMBIs, require recording as well as stimulation, we pay careful attention to isolation of the stimulus channels and parasitic current injection. With the realized device and standard recording hardware - without active artifact rejection - we are able to observe stimulus artifacts of less than 2 ms in duration. PMID:22328184

  16. Surface modification of biphasic calcium phosphate bioceramic powders

    NASA Astrophysics Data System (ADS)

    Yang, W. Z.; Zhou, D. L.; Yin, G. F.; Li, G. D.

    2008-11-01

    Biphasic calcium phosphate (BCP)/poly L-lactide (PLLA) biocomposite is proven to be a promising bone graft material or scaffold for bone tissue engineering. To improve the interfacial compatibility of BCP bioceramic with biopolymer-PLLA, BCP powders were surface-modified in different condition to graft polymer groups onto the surface of the BCP powders. L-lactide and L-lactic acid (LA) oligomer were used to modify the BCP surface with stannous octanoate (Sn(Oct) 2) and stannous chloride (SnCl 2) as catalyst, respectively. Results show that the surface modification effect is obvious and the amount of grafted organic group is above 6.5 wt.%. Sn(Oct) 2 and SnCl 2 are the optimal catalysts for the surface grafting reaction of L-lactide and L-LA oligomer, respectively. The surface grafting slightly increase the particle size of BCP powders and reduce the tendency for their agglomeration.

  17. High-side digitally current controlled biphasic bipolar microstimulator.

    PubMed

    Hanson, Timothy L; Ómarsson, Björn; O'Doherty, Joseph E; Peikon, Ian D; Lebedev, Mikhail A; Nicolelis, Miguel A L

    2012-05-01

    Electrical stimulation of nervous tissue has been extensively used as both a tool in experimental neuroscience research and as a method for restoring of neural functions in patients suffering from sensory and motor disabilities. In the central nervous system, intracortical microstimulation (ICMS) has been shown to be an effective method for inducing or biasing perception, including visual and tactile sensation. ICMS also holds promise for enabling brain-machine-brain interfaces (BMBIs) by directly writing information into the brain. Here we detail the design of a high-side, digitally current-controlled biphasic, bipolar microstimulator, and describe the validation of the device in vivo. As many applications of this technique, including BMBIs, require recording as well as stimulation, we pay careful attention to isolation of the stimulus channels and parasitic current injection. With the realized device and standard recording hardware-without active artifact rejection-we are able to observe stimulus artifacts of less than 2 ms in duration.

  18. Biphasic Role of Calcium in Mouse Sperm Capacitation Signaling Pathways

    PubMed Central

    Alvau, Antonio; Escoffier, Jessica; Krapf, Dario; Sánchez-Cárdenas, Claudia; Salicioni, Ana M.; Darszon, Alberto; Visconti, Pablo E.

    2016-01-01

    Mammalian sperm acquire fertilizing ability in the female tract in a process known as capacitation. At the molecular level, capacitation is associated with up-regulation of a cAMP-dependent pathway, changes in intracellular pH, intracellular Ca2+ and an increase in tyrosine phosphorylation. How these signaling systems interact during capacitation is not well understood. Results presented in this study indicate that Ca2+ ions have a biphasic role in the regulation of cAMP-dependent signaling. Media without added Ca2+ salts (nominal zero Ca2+) still contain micromolar concentrations of this ion. Sperm incubated in this medium did not undergo PKA activation or the increase in tyrosine phosphorylation suggesting that these phosphorylation pathways require Ca2+. However, chelation of the extracellular Ca2+ traces by EGTA induced both cAMP-dependent phosphorylation and the increase in tyrosine phosphorylation. The EGTA effect in nominal zero Ca2+ media was mimicked by two calmodulin antagonists, W7 and calmidazolium, and by the calcineurin inhibitor cyclosporine A. These results suggest that Ca2+ ions regulate sperm cAMP and tyrosine phosphorylation pathways in a biphasic manner and that some of its effects are mediated by calmodulin. Interestingly, contrary to wild type mouse sperm, sperm from CatSper1 KO mice underwent PKA activation and an increase in tyrosine phosphorylation upon incubation in nominal zero Ca2+ media. Therefore, sperm lacking Catsper Ca2+ channels behave as wild-type sperm incubated in the presence of EGTA. This latter result suggests that Catsper transports the Ca2+ involved in the regulation of cAMP-dependent and tyrosine phosphorylation pathways required for sperm capacitation. PMID:25597298

  19. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    SciTech Connect

    K. Osseo-Asare; X. Zeng

    2001-06-30

    Ever-stringent environmental constraints dictate that future coal cleaning technologies be compatible with micron-size particles. This research program seeks to develop an advanced coal cleaning technology uniquely suited to micron-size particles, i.e., aqueous biphase extraction. The partitioning behaviors of hematite in the dextran (Dex)/Triton X-100 (TX100) and polyethylene glycol (PEG)/dextran systems were investigated and the effects of some ionic surfactants on solid partition were studied. In both biphase systems, the particles stayed in the bottom dextran-rich phase under all pH conditions. This behavior is attributable to the fact that the hydrophilic oxide particles prefer the more hydrophilic bottom phase. Also, the strong favorable interaction between dextran and ferric oxide facilitates the dispersion of the solids in the polysaccharide-rich phase. In the Dex/TX100 system, addition of sodium dodecylsulfate (SDS) or potassium oleate had no effect on the solid partition; on the other hand, addition of dodecyltrimethylammonium bromide (DTAB) transferred the particles to the top phase or interface at high pH values. In the PEG/Dex system, the preferred location of hematite remained the bottom phase in the presence of either SDS or DTAB. The effects of anionic surfactants on the partition behavior are attributable to the fact that they are not able to replace the strongly adsorbed polysaccharide layer on the ferric oxide surface. The results with the cationic surfactant are due to electrostatic interaction between the cationic surfactant and the charged surface of the solid particles. The difference in solids partitioning in the two systems is the result of the different distribution of DTAB in these systems. In the Dex/TX100 system, DTAB prefers the top surfactant-rich phase, while it concentrates in the bottom phase in the PEG/dextran system.

  20. Copper: a biphasic regulator of caprine sperm forward progression.

    PubMed

    Roy, Debarun; Dey, Souvik; Majumder, Gopal Chandra; Bhattacharyya, Debdas

    2014-02-01

    Copper is essential for spermatogenesis and its presence has been demonstrated in male and female reproductive fluids in several mammalian species. However, little is known about the physiological significance of this trace element in the regulation of forward progression of mammalian sperm cells which is essential for sperm fertility potential in vivo. The purpose of this investigation was to determine the physiological role of the bivalent copper ion (Cu(2+)) on mammalian sperm forward motility using a chemically-defined medium and caprine cauda epididymal sperm model. Sperm forward motility was significantly enhanced by Cu(2+) in a dose-dependent manner; maximal activation (approx 20%) was noted at the 5 µM level of the metal. Above 10 µM Cu(2+) sperm motility decreased, showing that Cu(2+) exerts a biphasic regulation on sperm motility. These findings have been confirmed using a spectrophotometric motility assay, an objective method of motility analysis. At lower concentrations (up to 5 µM), copper enhanced sperm membrane lipid peroxidation as well as the level of intra-sperm cyclic adenosine mono phosphate (c-AMP), but at a higher level it caused marked inhibition of both of the biochemical parameters. The observed correlation of Cu(2+)-dependent biphasic modulation of sperm membrane lipid peroxidation and intrasperm c-AMP with sperm forward motility is consistent with the view that Cu(2+) regulation of sperm motility is mediated by membrane lipid peroxidation, which in turn modulates the level of intra-sperm c-AMP, a well-known activator of sperm motility.