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Sample records for nanostructured composite materials

  1. Nanostructured composite reinforced material

    DOEpatents

    Seals, Roland D [Oak Ridge, TN; Ripley, Edward B [Knoxville, TN; Ludtka, Gerard M [Oak Ridge, TN

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  2. Composite materials formed with anchored nanostructures

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2015-03-10

    A method of forming nano-structure composite materials that have a binder material and a nanostructure fiber material is described. A precursor material may be formed using a mixture of at least one metal powder and anchored nanostructure materials. The metal powder mixture may be (a) Ni powder and (b) NiAl powder. The anchored nanostructure materials may comprise (i) NiAl powder as a support material and (ii) carbon nanotubes attached to nanoparticles adjacent to a surface of the support material. The process of forming nano-structure composite materials typically involves sintering the mixture under vacuum in a die. When Ni and NiAl are used in the metal powder mixture Ni.sub.3Al may form as the binder material after sintering. The mixture is sintered until it consolidates to form the nano-structure composite material.

  3. Composite, nanostructured, super-hydrophobic material

    DOEpatents

    D'Urso, Brian R.; Simpson, John T.

    2007-08-21

    A hydrophobic disordered composite material having a protrusive surface feature includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite material having an etched surface wherein the protrusive phase protrudes from the surface to form a protrusive surface feature, the protrusive feature being hydrophobic.

  4. Composite Nanostructured Material Fabrication By Electrochemical Scanning Probe Microscopy

    DTIC Science & Technology

    1992-10-31

    achieve selective electrodeposition onto a nanostructured surface and in techniques and procedures needed to create a nanoheterostructure , a class of... nanoheterostructures . As an example of such a structure we would start with a nanostructure consisting of a metal film of material A which has nanometer-scale...selective electrodeposition onto a nanostructured surface and in techniques and procedures needed to create a nanoheterostructure . The first attempts to

  5. Nanostructured materials

    NASA Astrophysics Data System (ADS)

    Moriarty, Philip

    2001-03-01

    Nanostructured materials may be defined as those materials whose structural elements - clusters, crystallites or molecules - have dimensions in the 1 to 100 nm range. The explosion in both academic and industrial interest in these materials over the past decade arises from the remarkable variations in fundamental electrical, optical and magnetic properties that occur as one progresses from an `infinitely extended' solid to a particle of material consisting of a countable number of atoms. This review details recent advances in the synthesis and investigation of functional nanostructured materials, focusing on the novel size-dependent physics and chemistry that results when electrons are confined within nanoscale semiconductor and metal clusters and colloids. Carbon-based nanomaterials and nanostructures including fullerenes and nanotubes play an increasingly pervasive role in nanoscale science and technology and are thus described in some depth. Current nanodevice fabrication methods and the future prospects for nanostructured materials and nanodevices are discussed.

  6. A brief review on graphene/inorganic nanostructure composites: materials for the future

    NASA Astrophysics Data System (ADS)

    Mitra, S.; Banerjee, S.; Datta, A.; Chakravorty, D.

    2016-09-01

    The exotic physical properties of graphene have led to intense research activities on the synthesis and characterization of graphene composites during the last decade. The methods developed for preparation of such materials and the different application areas are reviewed. Mainly the inorganic nanostructure/graphene composites have been discussed. The techniques of ex-situ and in-situ hybridization respectively, have been pointed out. Some of the application areas such as batteries, ultracapacitors for energy storage, fuel cells and solar cells for energy generation are discussed. The possible future directions of research are highlighted.

  7. The Process of Nanostructuring of Metal (Iron) Matrix in Composite Materials for Directional Control of the Mechanical Properties

    PubMed Central

    Zemtsova, Elena

    2014-01-01

    We justified theoretical and experimental bases of synthesis of new class of highly nanostructured composite nanomaterials based on metal matrix with titanium carbide nanowires as dispersed phase. A new combined method for obtaining of metal iron-based composite materials comprising the powder metallurgy processes and the surface design of the dispersed phase is considered. The following stages of material synthesis are investigated: (1) preparation of porous metal matrix; (2) surface structuring of the porous metal matrix by TiC nanowires; (3) pressing and sintering to give solid metal composite nanostructured materials based on iron with TiC nanostructures with size 1–50 nm. This material can be represented as the material type “frame in the frame” that represents iron metal frame reinforcing the frame of different chemical compositions based on TiC. Study of material functional properties showed that the mechanical properties of composite materials based on iron with TiC dispersed phase despite the presence of residual porosity are comparable to the properties of the best grades of steel containing expensive dopants and obtained by molding. This will solve the problem of developing a new generation of nanostructured metal (iron-based) materials with improved mechanical properties for the different areas of technology. PMID:24695459

  8. The process of nanostructuring of metal (iron) matrix in composite materials for directional control of the mechanical properties.

    PubMed

    Zemtsova, Elena; Yurchuk, Denis; Smirnov, Vladimir

    2014-01-01

    We justified theoretical and experimental bases of synthesis of new class of highly nanostructured composite nanomaterials based on metal matrix with titanium carbide nanowires as dispersed phase. A new combined method for obtaining of metal iron-based composite materials comprising the powder metallurgy processes and the surface design of the dispersed phase is considered. The following stages of material synthesis are investigated: (1) preparation of porous metal matrix; (2) surface structuring of the porous metal matrix by TiC nanowires; (3) pressing and sintering to give solid metal composite nanostructured materials based on iron with TiC nanostructures with size 1-50 nm. This material can be represented as the material type "frame in the frame" that represents iron metal frame reinforcing the frame of different chemical compositions based on TiC. Study of material functional properties showed that the mechanical properties of composite materials based on iron with TiC dispersed phase despite the presence of residual porosity are comparable to the properties of the best grades of steel containing expensive dopants and obtained by molding. This will solve the problem of developing a new generation of nanostructured metal (iron-based) materials with improved mechanical properties for the different areas of technology.

  9. Lightweight Beryllium Free Nanostructured Nanostructured Composites

    DTIC Science & Technology

    2007-11-02

    Plasma Processes, Inc. Lightweight Beryllium Free Nanostructured Composites SBIR Contract DASG60-02-P-41 Phase I Final Report 1/15/03 Submitted by...Report Type N/A Dates Covered (from... to) - Title and Subtitle Lightweight Beryllium Free Nanostructured Nanostructured Composites Contract

  10. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    NASA Astrophysics Data System (ADS)

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-03-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10–20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed.

  11. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors.

    PubMed

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-03-14

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10-20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed.

  12. Hydrothermal synthesis of nanostructured graphene/polyaniline composites as high-capacitance electrode materials for supercapacitors

    PubMed Central

    Wang, Ronghua; Han, Meng; Zhao, Qiannan; Ren, Zonglin; Guo, Xiaolong; Xu, Chaohe; Hu, Ning; Lu, Li

    2017-01-01

    As known to all, hydrothermal synthesis is a powerful technique for preparing inorganic and organic materials or composites with different architectures. In this reports, by controlling hydrothermal conditions, nanostructured polyaniline (PANi) in different morphologies were composited with graphene sheets (GNS) and used as electrode materials of supercapacitors. Specifically, ultrathin PANi layers with total thickness of 10–20 nm are uniformly composited with GNS by a two-step hydrothermal-assistant chemical oxidation polymerization process; while PANi nanofibers with diameter of 50~100 nm are obtained by a one-step direct hydrothermal process. Benefitting from the ultrathin layer and porous structure, the sheet-like GNS/PANi composites can deliver specific capacitances of 532.3 to 304.9 F/g at scan rates of 2 to 50 mV/s. And also, this active material showed very good stability with capacitance retention as high as ~99.6% at scan rate of 50 mV/s, indicating a great potential for using in supercapacitors. Furthermore, the effects of hydrothermal temperatures on the electrochemical performances were systematically studied and discussed. PMID:28291246

  13. Nanostructured Carbon/Antimony Composites as Anode Materials for Lithium-Ion Batteries with Long Life.

    PubMed

    Cheng, Yong; Yi, Zheng; Wang, Chunli; Wang, Lidong; Wu, Yaoming; Wang, Limin

    2016-08-05

    A series of nanostructured carbon/antimony composites have been successfully synthesized by a simple sol-gel, high-temperature carbon thermal reduction process. In the carbon/antimony composites, antimony nanoparticles are homogeneously dispersed in the pyrolyzed nanoporous carbon matrix. As an anode material for lithium-ion batteries, the C/Sb10 composite displays a high initial discharge capacity of 1214.6 mAh g(-1) and a reversible charge capacity of 595.5 mAh g(-1) with a corresponding coulombic efficiency of 49 % in the first cycle. In addition, it exhibits a high reversible discharge capacity of 466.2 mAh g(-1) at a current density of 100 mA g(-1) after 200 cycles and a high rate discharge capacity of 354.4 mAh g(-1) at a current density of 1000 mA g(-1) . The excellent cycling stability and rate discharge performance of the C/Sb10 composite could be due to the uniform dispersion of antimony nanoparticles in the porous carbon matrix, which can buffer the volume expansion and maintain the integrity of the electrode during the charge-discharge cycles.

  14. Nanostructured materials in potentiometry.

    PubMed

    Düzgün, Ali; Zelada-Guillén, Gustavo A; Crespo, Gastón A; Macho, Santiago; Riu, Jordi; Rius, F Xavier

    2011-01-01

    Potentiometry is a very simple electrochemical technique with extraordinary analytical capabilities. It is also well known that nanostructured materials display properties which they do not show in the bulk phase. The combination of the two fields of potentiometry and nanomaterials is therefore a promising area of research and development. In this report, we explain the fundamentals of potentiometric devices that incorporate nanostructured materials and we highlight the advantages and drawbacks of combining nanomaterials and potentiometry. The paper provides an overview of the role of nanostructured materials in the two commonest potentiometric sensors: field-effect transistors and ion-selective electrodes. Additionally, we provide a few recent examples of new potentiometric sensors that are based on receptors immobilized directly onto the nanostructured material surface. Moreover, we summarize the use of potentiometry to analyze processes involving nanostructured materials and the prospects that the use of nanopores offer to potentiometry. Finally, we discuss several difficulties that currently hinder developments in the field and some future trends that will extend potentiometry into new analytical areas such as biology and medicine.

  15. Synthesis and characterization of bismuth telluride based nanostructured thermoelectric composite materials

    NASA Astrophysics Data System (ADS)

    Keshavarz Khorasgani, Mohsen

    Thermoelectric (TE) materials and devices are attractive in solid-state energy conversion applications such as waste heat recovery, air-conditioning, and refrigeration. Since the 1950's lots of unremitting efforts have been made to enhance the efficiency of energy conversion in TE materials (i. e. improving the figure of merit (ZT)), however, most of commercial bulk TE materials still suffer from low efficiency with ZTs around unity. To enhance the performance of bismuth telluride based TE alloys, we have developed composite TE materials, based on the idea that introducing more engineered interfaces in the bulk TE materials may lead to thermal conductivity reduction due to increased phonon scattering by these interfaces. In this approach it is expected that the electronic transport properties of the material are not effectively affected. Consequently, ZT enhancement can be achieved. In this dissertation we will discuss synthesis and characterization of two types of bismuth telluride based bulk composite TE materials. The first type is engineered to contain the presence of coherent interfaces between phases in the material resulting from different mixtures of totally miscible compounds with similar composition. The second type includes the nanocomposites with embedded foreign nano-particles in which the matrix and the particles are delimited by incoherent interfaces. The synthesis procedure, micro- and nano-structures as well as thermoelectric properties of these composites will be presented. In our study on the composites with coherent interfaces, we produced a series of different composites of p-type bismuth antimony telluride alloys and studied their microstructure and thermoelectric properties. Each composite consists of two phases that were obtained in powder form by mechanical alloying. Mixed powders in various proportions of the two different phases were consolidated by hot extrusion to obtain each bulk composite. The minimum grain size of bulk composites as

  16. Nanostructured materials for hydrogen storage

    DOEpatents

    Williamson, Andrew J.; Reboredo, Fernando A.

    2007-12-04

    A system for hydrogen storage comprising a porous nano-structured material with hydrogen absorbed on the surfaces of the porous nano-structured material. The system of hydrogen storage comprises absorbing hydrogen on the surfaces of a porous nano-structured semiconductor material.

  17. Nanostructured TiO2-coated activated carbon composite as an electrode material for asymmetric hybrid capacitors.

    PubMed

    Kim, Sang-Ok; Lee, Joong Kee

    2012-02-01

    A nanostructured TiO2-coated activated carbon (TAC) composite was synthesized by a modified sol-gel reaction and employed it as a negative electrode active material for an asymmetric hybrid capacitor. The structural characterization showed that the TiO2 nano-layer was deposited on the surface of the activated carbon and the TAC composite has a highly mesoporous structure. The evaluation of electrochemical characteristics of the TAC electrode was carried out by galvanostatic charge/discharge cycling tests and electrochemical impedance spectroscopy. The obtained specific capacitance of the TAC composite was 42.87 F/g, which showed by 27.1% higher than that of the activated carbon (AC). The TAC composite also exhibited an excellent cycle performance and kept 95% of initial capacitance over 500 cycles.

  18. Microstructure and composition analysis of nanostructured materials using HREM and FEG-TEM

    PubMed

    Li; Ping; Huang; Yu; Ye

    2000-10-01

    The microstructure in nanostructured (NS) materials synthesized by different methods have been characterized by electron microscopy methods. NS-Pd was prepared by inert-gas condensation and in situ compacting method (IGCC), NS-alloys by amorphous crystallization method (ACM) and NS-Cu and Cu100-xFe(x) alloy by mechanical alloying (MA) methods. The experimental results have revealed that different preparation techniques lead to different microstructures. The grain boundaries have ordered and disordered structures and high density of defects were frequently detected in NS-materials synthesized by IGCC and MA. For the NS-alloys produced by ACM, however, the structures of GBs are similar to those in coarse-grained materials and the grains have nearly perfect crystal structure. For immiscible systems, a supersaturated Fe-Cu solid solution can be obtained by MA, but it is difficult using IGCC.

  19. Incorporation of ZnO and their composite nanostructured material into a cotton fabric platform for wearable device applications.

    PubMed

    Veluswamy, Pandiyarasan; Sathiyamoorthy, Suhasini; Khan, Faizan; Ghosh, Aranya; Abhijit, Majumdar; Hayakawa, Yasuhiro; Ikeda, Hiroya

    2017-02-10

    The central idea of this paper is to innovate a new approach for the development of wearable device materials through the coating of cotton fabric with ZnO and Sb-/Ag-/ZnO composites. The study was designed in order to have a clear understanding of the role of ZnO as well as the modified composite thereof under investigation. Cotton fabric with uniform ZnO/ZnO-composite layers on the surface was successfully synthesized via a solvothermal method. The growth behaviors were investigated by comparing ZnO and ZnO-composites. The structural, morphological, chemical states, optical, electrical and thermopower properties of these fabrics were studied. Nanostructured ZnO-composite fabric had enhanced UV shielding with a value of 83.96. It is found that the ZnO-composite fabrics have increased electrical conductivity. The thermopower value of the ZnO-composite fabric could reach 471.9μVK(-1). Such materials are anticipated to be worthwhile as wearable electronic devices and as protective textiles.

  20. Lyotropic liquid crystal engineering moving beyond binary compositional space - ordered nanostructured amphiphile self-assembly materials by design.

    PubMed

    van 't Hag, Leonie; Gras, Sally L; Conn, Charlotte E; Drummond, Calum J

    2017-03-10

    Ordered amphiphile self-assembly materials with a tunable three-dimensional (3D) nanostructure are of fundamental interest, and crucial for progressing several biological and biomedical applications, including in meso membrane protein crystallization, as drug and medical contrast agent delivery vehicles, and as biosensors and biofuel cells. In binary systems consisting of an amphiphile and a solvent, the ability to tune the 3D cubic phase nanostructure, lipid bilayer properties and the lipid mesophase is limited. A move beyond the binary compositional space is therefore required for efficient engineering of the required material properties. In this critical review, the phase transitions upon encapsulation of more than 130 amphiphilic and soluble additives into the bicontinuous lipidic cubic phase under excess hydration are summarized. The data are interpreted using geometric considerations, interfacial curvature, electrostatic interactions, partition coefficients and miscibility of the alkyl chains. The obtained lyotropic liquid crystal engineering design rules can be used to enhance the formulation of self-assembly materials and provides a large library of these materials for use in biomedical applications (242 references).

  1. Nanostructured Materials for Solar Cells

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila; Raffaelle, Ryne; Castro, Stephanie; Fahey, S.; Gennett, T.; Tin, P.

    2003-01-01

    The use of both inorganic and organic nanostructured materials in producing high efficiency photovoltaics is discussed in this paper. Recent theoretical results indicate that dramatic improvements in device efficiency may be attainable through the use of semiconductor quantum dots in an ordinary p-i-n solar cell. In addition, it has also recently been demonstrated that quantum dots can also be used to improve conversion efficiencies in polymeric thin film solar cells. A similar improvement in these types of cells has also been observed by employing single wall carbon nanotubes. This relatively new carbon allotrope may assist both in the disassociation of excitons as well as carrier transport through the composite material. This paper reviews the efforts that are currently underway to produce and characterize these nanoscale materials and to exploit their unique properties.

  2. Nanostructured Energetic Materials

    DTIC Science & Technology

    2006-11-01

    for the nanoenergetic composites prepared using mesoporous Fe2O3 gel, nanoparticles of WO3, MoO3, Bi2O3 , and CuO mixed with Al-nanoparticles and...used in the energetic composite. For example, in the energetic reactions of the composites containing Fe2O3, WO3, MoO3, Bi2O3 , and CuO, combined...MA), WO3 (Aldrich, WI), MoO3 and Bi2O3 (Accumet Materials, NY) and nanoparticles of Al (avg. size 80 nm with 2 nm passivation layer from

  3. Hierarchically Nanostructured Materials for Sustainable Environmental Applications

    NASA Astrophysics Data System (ADS)

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-11-01

    This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

  4. Hierarchically nanostructured materials for sustainable environmental applications

    PubMed Central

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-01-01

    This review presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions, and multiple functionalities toward water remediation, biosensing, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing, and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology. PMID:24790946

  5. Nanostructured Black Phosphorus/Ketjenblack-Multiwalled Carbon Nanotubes Composite as High Performance Anode Material for Sodium-Ion Batteries.

    PubMed

    Xu, Gui-Liang; Chen, Zonghai; Zhong, Gui-Ming; Liu, Yuzi; Yang, Yong; Ma, Tianyuan; Ren, Yang; Zuo, Xiaobing; Wu, Xue-Hang; Zhang, Xiaoyi; Amine, Khalil

    2016-06-08

    Sodium-ion batteries are promising alternatives to lithium-ion batteries for large-scale applications. However, the low capacity and poor rate capability of existing anodes for sodium-ion batteries are bottlenecks for future developments. Here, we report a high performance nanostructured anode material for sodium-ion batteries that is fabricated by high energy ball milling to form black phosphorus/Ketjenblack-multiwalled carbon nanotubes (BPC) composite. With this strategy, the BPC composite with a high phosphorus content (70 wt %) could deliver a very high initial Coulombic efficiency (>90%) and high specific capacity with excellent cyclability at high rate of charge/discharge (∼1700 mAh g(-1) after 100 cycles at 1.3 A g(-1) based on the mass of P). In situ electrochemical impedance spectroscopy, synchrotron high energy X-ray diffraction, ex situ small/wide-angle X-ray scattering, high resolution transmission electronic microscopy, and nuclear magnetic resonance were further used to unravel its superior sodium storage performance. The scientific findings gained in this work are expected to serve as a guide for future design on high performance anode material for sodium-ion batteries.

  6. An investigation of electromagnetic response of composite polymer materials containing carbon nanostructures within the range of frequencies 10 MHz - 1.1 THz

    NASA Astrophysics Data System (ADS)

    Suslyaev, V. I.; Kuznetsov, V. L.; Zhuravlev, V. A.; Mazov, I. N.; Korovin, E. Yu.; Moseenkov, S. I.; Dorozhkin, K. V.

    2013-01-01

    Electromagnetic characteristics of composite polymer materials based on multilayer carbon nanotubes (MCNTs) and nano-onion carbon structures in a polymethylmethacrylate (PMMA) matrix are investigated. The purpose is to identify a functional relationship between the size, kind, type of processing, concentration of nanotubes and electromagnetic characteristics of composite materials within the frequency range 10 MHz - 1.1 THz. Use is made of the coaxial waveguide, resonator, and quasi-optical methods. The spectra of reflection and transmission coefficients are reported. The composite materials based on carbon nanostructures are shown to actively interact with electromagnetic radiation in a wide range of frequencies.

  7. Surface doping of composite plasmonic material by functional graphene nanostructures for organic solar cell applications

    NASA Astrophysics Data System (ADS)

    Chen, Chi-Chu; Yang, Cheng-Du; Kao, Yi-Lun; Chiu, Nan-Fu

    2015-05-01

    In this paper, we're binding gold nanoparticles (GNPs) and reduced graphene oxide (rGO) by cystamine (Cys). The PEDOT:PSS mix GNPs/Cys/rGO as a hole transport layer of the solar cell. From the experimental result shows the PEDOT:PSS/GNPs/Cys/rGO/ITO film than ITO film have the best transmittance. It's transmittance was decreased for 1.01% at 545 nm wavelength. The sheet resistance of PEDOT:PSS/GNPs/Cys/rGO/ITO was reduce than PEDOT:PSS/ITO, when it was doped with Gold nanoparticles (GNPs) and rGO on ITO glass. The former is than the latter decreased for 1%. For these reasons due to impact by surface doping of composite plasmonic material.

  8. Nanostructured conductive polymeric materials

    NASA Astrophysics Data System (ADS)

    Al-Saleh, Mohammed H.

    Conductive polymer composites (CPCs) are a suitable alternative to metals in many applications due to their light-weight, corrosion resistance, low cost, ease of processing and design flexibility. CPCs have been formulated using different types of conductive fillers. In this PhD thesis, the focus is on CPCs for electrostatic discharge (ESD) protection and electromagnetic interference (EMI) attenuation. Despite the versatility of conductive fillers, carbon black (CB) has been the dominant filler to make CPCs for ESD protection applications because CB/polymer composites have a cost advantage over all other CPCs. For EMI shielding, stainless steel fibres and metal coated fibers are the preferred fillers, however CPCs made of those fibers are not the dominant EMI shielding materials. Metal coated and polymer plated polymers are the most widely used EMI shielding options. The limited use of CPCs in the EMI shielding market is because the high filler loading required to formulate a composite with an adequate level of shielding remarkably increases the composite price. In order to increase the competitiveness of CPCs, percolation threshold should be minimized as much as possible and composites with high EMI shielding capabilities at low filler loading should be formulated because all conductive fillers are expensive compared to polymers. In this thesis, two different methodologies to reduce percolation threshold in CPCs have been successfully developed and a CPC with exceptional EMI shielding capability has been formulated using copper nanowires as conductive filler. The first percolation threshold reduction technique is based on the selective localization of CB at the interface of immiscible polymer blend. The technique requires adding a copolymer that prefers the blend's interface and for which CB nanoparticles has the highest affinity. The second method is based on producing a CPC powder and then using this powder as a conductive filler to produce composite by dry

  9. Nano-structured composite of Si/(S-doped-carbon nanowire network) as anode material for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Shao, Dan; Tang, Daoping; Yang, Jianwen; Li, Yanwei; Zhang, Lingzhi

    2015-11-01

    Novel nanostructured silicon composites, Si/Poly(3,4-ethylenedioxythiophene) nanowire network (Si/PNW) and Si/(S-doped-carbon nanowire network) (Si/S-CNW), are prepared by a soft-template polymerization of 3,4-ethylenedioxythiophene (EDOT) using sodium dodecyl sulfate (SDS) as surfactant with the presence of Si nanoparticles and a subsequent carbonization of Si/PNW, respectively. The presence of Si nanoparticles in the soft-template polymerization of EDOT plays a critical role in the formation of PEDOT nanowire network instead of 1D nanowire. After the carbonization of PEDOT, the S-doped-carbon nanowire network matrix shows higher electrical conductivity than PNW counterpart, which facilitates to construct robust conductive bridges between Si nanoparticles and provide large electrode/electrolyte interfaces for rapid charge transfer reactions. Thus, Si/S-CNW composite exhibits excellent cycling stability and rate capability as anode material, retaining a specific capacity of 820 mAh g-1 after 400 cycles with a very small capacity fade of 0.09% per cycle.

  10. Block copolymer based composition and morphology control in nanostructured hybrid materials for energy conversion and storage: solar cells, batteries, and fuel cells.

    PubMed

    Orilall, M Christopher; Wiesner, Ulrich

    2011-02-01

    The development of energy conversion and storage devices is at the forefront of research geared towards a sustainable future. However, there are numerous issues that prevent the widespread use of these technologies including cost, performance and durability. These limitations can be directly related to the materials used. In particular, the design and fabrication of nanostructured hybrid materials is expected to provide breakthroughs for the advancement of these technologies. This tutorial review will highlight block copolymers as an emerging and powerful yet affordable tool to structure-direct such nanomaterials with precise control over structural dimensions, composition and spatial arrangement of materials in composites. After providing an introduction to materials design and current limitations, the review will highlight some of the most recent examples of block copolymer structure-directed nanomaterials for photovoltaics, batteries and fuel cells. In each case insights are provided into the various underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-polymer chemistry methodologies for the efficient creation of multiscale functional materials. Examples include nanostructured ceramics, ceramic-carbon composites, ceramic-carbon-metal composites and metals with morphologies ranging from hexagonally arranged cylinders to three-dimensional bi-continuous cubic networks. The review ends with an outlook towards the synthesis of multicomponent and hierarchical multifunctional hybrid materials with different nano-architectures from self-assembly of higher order blocked macromolecules which may ultimately pave the way for the further development of energy conversion and storage devices.

  11. Atomistic simulation of nanostructured materials

    NASA Astrophysics Data System (ADS)

    Zhu, Ronghua

    Atomistic based computer modeling and simulation of nanostructured materials has become an important subfield of materials research. Based on the multiresolution method, which combines the continuum mechanics, kinetic Monte Carlo method and molecular dynamics method, we study the nanostructured materials grown by quantum-dot self-assembly, mechanical properties of strained semiconductors, and mechanical properties of carbon nanotube reinforced composites. This thesis covers the following three main contributions. 1. Self-organization of semiconductors InAs/GaAs in Stranski-Krastanov growth mode is studied using kinetic Monte Carlo simulations method coupled with the Green's function solution for the elastic strain energy distribution. The relevant growth parameters such as growth temperature, surface coverage, flux rate, and growth interruption time are investigated. It is shown clearly that when the long-range strain energy is included in the simulation, ordered uniform size distribution can be achieved. To address the effect of material anisotropy, the anisotropic substrates of GaAs with different growth orientations (001), (111), and (113) and an isotropic substrate Iso (001), reduced from cubic GaAs, are also investigated. Simulation results show that at selected growth parameters for temperature, coverage, and growth interruption time, strain energy field in the substrate is the key factor that controls the pattern of island distribution. Furthermore, layer-by-layer growth of quantum dots is also simulated briefly, and vertical alignment is observed that could lead to progressively uniform island sizes and spatial ordering. 2. Since the misfit strain will be induced during the quantum dots epitaxial growth, the mechanical property of the grown semiconductors will be influenced. In this thesis, utilizing the basic continuum mechanics, we present a molecular dynamic prediction for the elastic stiffness C11, C12 and C 44 in strained silicon and InAs as functions

  12. Hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite positive electrode materials for rechargeable lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Zegeye, Tilahun Awoke; Kuo, Chung-Feng Jeffrey; Wotango, Aselefech Sorsa; Pan, Chun-Jern; Chen, Hung-Ming; Haregewoin, Atetegeb Meazah; Cheng, Ju-Hsiang; Su, Wei-Nien; Hwang, Bing-Joe

    2016-08-01

    Herein, we design hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite (MC-Meso C-doped TiO2/S) as a positive electrode material for lithium-sulfur batteries. The hybrid MC-Meso C-doped TiO2 host material is produced by a low-cost, hydrothermal and annealing process. The resulting conductive material shows dual microporous and mesoporous behavior which enhances the effective trapping of sulfur and polysulfides. The hybrid MC-Meso C-doped TiO2/S composite material possesses rutile TiO2 nanotube structure with successful carbon doping while sulfur is uniformly distributed in the hybrid MC-Meso C-doped TiO2 composite materials after the melt-infusion process. The electrochemical measurement of the hybrid material also shows improved cycle stability and rate performance with high sulfur loading (61.04%). The material delivers an initial discharge capacity of 802 mAh g-1 and maintains it at 578 mAh g-1 with a columbic efficiency greater than 97.1% after 140 cycles at 0.1 C. This improvement is thought to be attributed to the unique hybrid nanostructure of the MC-Meso C-doped TiO2 host and the good dispersion of sulfur in the narrow pores of the MC spheres and the mesoporous C-doped TiO2 support.

  13. Nanostructured composite material graphite/TiO2 and its antibacterial activity under visible light irradiation.

    PubMed

    Dědková, Kateřina; Lang, Jaroslav; Matějová, Kateřina; Peikertová, Pavlína; Holešinský, Jan; Vodárek, Vlastimil; Kukutschová, Jana

    2015-08-01

    The paper addresses laboratory preparation, characterization and in vitro evaluation of antibacterial activity of graphite/TiO2 nanocomposites. Composites graphite/TiO2 with various ratio of TiO2 nanoparticles (30wt.%, and 50wt.%) to graphite were prepared using a thermal hydrolysis of titanylsulfate in the presence of graphite particles, and subsequently dried at 80°C. X-ray powder diffraction, transmission electron microscopy and Raman microspectroscopy served as phase-analytical methods distinguishing anatase and rutile phases in the prepared composites. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A developed modification of the standard microdilution test was used for in vitro evaluation of daylight induced antibacterial activity, using four common human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Antibacterial activity of the graphite/TiO2 nanocomposites could be based mainly on photocatalytic reaction with subsequent potential interaction of reactive oxygen species with bacterial cells. During the antibacterial activity experiments, the graphite/TiO2 nanocomposites exhibited antibacterial activity, where differences in the onset of activity and activity against bacterial strains were observed. The highest antibacterial activity evaluated as minimum inhibitory concentration was observed against P. aeruginosa after 180min of irradiation.

  14. Nanostructured Ti-Zr-Pd-Si-(Nb) bulk metallic composites: Novel biocompatible materials with superior mechanical strength and elastic recovery.

    PubMed

    Hynowska, A; Blanquer, A; Pellicer, E; Fornell, J; Suriñach, S; Baró, M D; Gebert, A; Calin, M; Eckert, J; Nogués, C; Ibáñez, E; Barrios, L; Sort, J

    2015-11-01

    The microstructure, mechanical behaviour, and biocompatibility (cell culture, morphology, and cell adhesion) of nanostructured Ti45 Zr15 Pd35- x Si5 Nbx with x = 0, 5 (at. %) alloys, synthesized by arc melting and subsequent Cu mould suction casting, in the form of rods with 3 mm in diameter, are investigated. Both Ti-Zr-Pd-Si-(Nb) materials show a multi-phase (composite-like) microstructure. The main phase is cubic β-Ti phase (Im3m) but hexagonal α-Ti (P63/mmc), cubic TiPd (Pm3m), cubic PdZr (Fm3m), and hexagonal (Ti, Zr)5 Si3 (P63/mmc) phases are also present. Nanoindentation experiments show that the Ti45 Zr15 Pd30 Si5 Nb5 sample exhibits lower Young's modulus than Ti45 Zr15 Pd35 Si5 . Conversely, Ti45 Zr15 Pd35 Si5 is mechanically harder. Actually, both alloys exhibit larger values of hardness when compared with commercial Ti-40Nb, (HTi-Zr-Pd-Si ≈ 14 GPa, HTi-Zr-Pd-Si-Nb ≈ 10 GPa and HTi-40Nb ≈ 2.7 GPa). Concerning the biological behaviour, preliminary results of cell viability performed on several Ti-Zr-Pd-Si-(Nb) discs indicate that the number of live cells is superior to 94% in both cases. The studied Ti-Zr-Pd-Si-(Nb) bulk metallic system is thus interesting for biomedical applications because of the outstanding mechanical properties (relatively low Young's modulus combined with large hardness), together with the excellent biocompatibility.

  15. Prediction of Material Properties of Nanostructured Polymer Composites Using Atomistic Simulations

    NASA Technical Reports Server (NTRS)

    Hinkley, J.A.; Clancy, T.C.; Frankland, S.J.V.

    2009-01-01

    Atomistic models of epoxy polymers were built in order to assess the effect of structure at the nanometer scale on the resulting bulk properties such as elastic modulus and thermal conductivity. Atomistic models of both bulk polymer and carbon nanotube polymer composites were built. For the bulk models, the effect of moisture content and temperature on the resulting elastic constants was calculated. A relatively consistent decrease in modulus was seen with increasing temperature. The dependence of modulus on moisture content was less consistent. This behavior was seen for two different epoxy systems, one containing a difunctional epoxy molecule and the other a tetrafunctional epoxy molecule. Both epoxy structures were crosslinked with diamine curing agents. Multifunctional properties were calculated with the nanocomposite models. Molecular dynamics simulation was used to estimate the interfacial thermal (Kapitza) resistance between the carbon nanotube and the surrounding epoxy matrix. These estimated values were used in a multiscale model in order to predict the thermal conductivity of a nanocomposite as a function of the nanometer scaled molecular structure.

  16. Nanostructured materials for thermoelectric applications.

    PubMed

    Bux, Sabah K; Fleurial, Jean-Pierre; Kaner, Richard B

    2010-11-28

    Recent studies indicate that nanostructuring can be an effective method for increasing the dimensionless thermoelectric figure of merit (ZT) in materials. Most of the enhancement in ZT can be attributed to large reductions in the lattice thermal conductivity due to increased phonon scattering at interfaces. Although significant gains have been reported, much higher ZTs in practical, cost-effective and environmentally benign materials are needed in order for thermoelectrics to become effective for large-scale, wide-spread power and thermal management applications. This review discusses the various synthetic techniques that can be used in the production of bulk scale nanostructured materials. The advantages and disadvantages of each synthetic method are evaluated along with guidelines and goals presented for an ideal thermoelectric material. With proper optimization, some of these techniques hold promise for producing high efficiency devices.

  17. Nanoprobes, nanostructured materials and solid state materials

    NASA Astrophysics Data System (ADS)

    Yin, Houping

    2005-07-01

    Novel templates have been developed to prepare nanostructured porous materials through nonsurfactant templated pathway. And new applications of these materials, such as drug delivery and molecular imprinting, have been explored. The relationship between template content and pore structure has been investigated. The composition and pore structures were studied in detail using IR, TGA, SEM, TEM, BET and XRD. The obtained mesoporous materials have tunable diameters in the range of 2--12 nm. Due to the many advantages of this nonsurfactant templated pathway, such as environment friendly and biocompatibility, controlled release of antibiotics in the nanoporous materials were studied. The in vitro release properties were found to depend on the silica structures which were well tuned by varying the template content. A controlled long-term release pattern of vancomycin was achieved when the template content was 30 wt% or lower. Nanoscale electrochemical probes with dimensions as small as 50 nm in diameter and 1--2 mum in length were fabricated using electron beam deposition on the apex of conventional micron size electrodes. The electroactive region was limited to the extreme tip of the nanoprobe by coating with an insulating polymer and re-opening of the coating at the extreme tip. The novel nanoelectrodes thus prepared were employed to probe neurons in mouse brain slice and the results suggest that the nanoprobes were capable of recording neuronal excitatory postsynaptic potential signals. Interesting solid state chemistry was found in oxygenated iron phthalocyanine. Their Mossbauer spectra show the formation of four oxygenated species apart from the unoxygenated parent compound. The oxygen-bridged compounds formed in the solid matrix bear no resemblance to the one formed by solution chemistry. Tentative assignment of species has been made with the help of Mossbauer and IR spectroscopy. An effort to modify aniline trimer for potential nanoelectronics applications and to

  18. Method of fabrication of anchored nanostructure materials

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-11-26

    Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.

  19. Superconducting nanostructured materials.

    SciTech Connect

    Metlushko, V.

    1998-07-13

    Within the last year it has been realized that the remarkable properties of superconducting thin films containing a periodic array of defects (such as sub-micron sized holes) offer a new route for developing a novel superconducting materials based on precise control of microstructure by modern photolithography. A superconductor is a material which, when cooled below a certain temperature, loses all resistance to electricity. This means that superconducting materials can carry large electrical currents without any energy loss--but there are limits to how much current can flow before superconductivity is destroyed. The current at which superconductivity breaks down is called the critical current. The value of the critical current is determined by the balance of Lorentz forces and pinning forces acting on the flux lines in the superconductor. Lorentz forces proportional to the current flow tend to drive the flux lines into motion, which dissipates energy and destroys zero resistance. Pinning forces created by isolated defects in the microstructure oppose flux line motion and increase the critical current. Many kinds of artificial pinning centers have been proposed and developed to increase critical current performance, ranging from dispersal of small non-superconducting second phases to creation of defects by proton, neutron or heavy ion irradiation. In all of these methods, the pinning centers are randomly distributed over the superconducting material, causing them to operate well below their maximum efficiency. We are overcome this drawback by creating pinning centers in aperiodic lattice (see Fig 1) so that each pin site interacts strongly with only one or a few flux lines.

  20. Nanostructured cathode materials for rechargeable lithium batteries

    NASA Astrophysics Data System (ADS)

    Myung, Seung-Taek; Amine, Khalil; Sun, Yang-Kook

    2015-06-01

    The prospect of drastic climate change and the ceaseless fluctuation of fossil fuel prices provide motivation to reduce the use of fossil fuels and to find new energy conversion and storage systems that are able to limit carbon dioxide generation. Among known systems, lithium-ion batteries are recognized as the most appropriate energy storage system because of their high energy density and thus space saving in applications. Introduction of nanotechnology to electrode material is beneficial to improve the resulting electrode performances such as capacity, its retention, and rate capability. The nanostructure is highly available not only when used alone but also is more highlighted when harmonized in forms of core-shell structure and composites with carbon nanotubes, graphene or reduced graphene oxides. This review covers syntheses and electrochemical properties of nanoscale, nanosized, and nanostructured cathode materials for rechargeable lithium batteries.

  1. Composite material

    DOEpatents

    Hutchens, Stacy A [Knoxville, TN; Woodward, Jonathan [Solihull, GB; Evans, Barbara R [Oak Ridge, TN; O'Neill, Hugh M [Knoxville, TN

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  2. Anchored nanostructure materials and method of fabrication

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2012-11-27

    Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.

  3. Quantitative Characterization of Nanostructured Materials

    SciTech Connect

    Dr. Frank Bridges, University of California-Santa Cruz

    2010-08-05

    The two-and-a-half day symposium on the "Quantitative Characterization of Nanostructured Materials" will be the first comprehensive meeting on this topic held under the auspices of a major U.S. professional society. Spring MRS Meetings provide a natural venue for this symposium as they attract a broad audience of researchers that represents a cross-section of the state-of-the-art regarding synthesis, structure-property relations, and applications of nanostructured materials. Close interactions among the experts in local structure measurements and materials researchers will help both to identify measurement needs pertinent to real-world materials problems and to familiarize the materials research community with the state-of-the-art local structure measurement techniques. We have chosen invited speakers that reflect the multidisciplinary and international nature of this topic and the need to continually nurture productive interfaces among university, government and industrial laboratories. The intent of the symposium is to provide an interdisciplinary forum for discussion and exchange of ideas on the recent progress in quantitative characterization of structural order in nanomaterials using different experimental techniques and theory. The symposium is expected to facilitate discussions on optimal approaches for determining atomic structure at the nanoscale using combined inputs from multiple measurement techniques.

  4. Nanostructured materials in electroanalysis of pharmaceuticals.

    PubMed

    Rahi, A; Karimian, K; Heli, H

    2016-03-15

    Basic strategies and recent developments for the enhancement of the sensory performance of nanostructures in the electroanalysis of pharmaceuticals are reviewed. A discussion of the properties of nanostructures and their application as modified electrodes for drug assays is presented. The electrocatalytic effect of nanostructured materials and their application in determining low levels of drugs in pharmaceutical forms and biofluids are discussed.

  5. Nanostructured energetic composites: synthesis, ignition/combustion modeling, and applications.

    PubMed

    Zhou, Xiang; Torabi, Mohsen; Lu, Jian; Shen, Ruiqi; Zhang, Kaili

    2014-03-12

    Nanotechnology has stimulated revolutionary advances in many scientific and industrial fields, particularly in energetic materials. Powder mixing is the simplest and most traditional method to prepare nanoenergetic composites, and preliminary findings have shown that these composites perform more effectively than their micro- or macro-sized counterparts in terms of energy release, ignition, and combustion. Powder mixing technology represents only the minimum capability of nanotechnology to boost the development of energetic material research, and it has intrinsic limitations, namely, random distribution of fuel and oxidizer particles, inevitable fuel pre-oxidation, and non-intimate contact between reactants. As an alternative, nanostructured energetic composites can be prepared through a delicately designed process. These composites outperform powder-mixed nanocomposites in numerous ways; therefore, we comprehensively discuss the preparation strategies adopted for nanostructured energetic composites and the research achievements thus far in this review. The latest ignition and reaction models are briefly introduced. Finally, the broad promising applications of nanostructured energetic composites are highlighted.

  6. Clay nanotube composites for antibacterial nanostructured coatings

    NASA Astrophysics Data System (ADS)

    Boyer, Christen J.

    A surging demand for the development of new antimicrobial nanomaterials exists due to the frequency of medical device-associated infections and the transfer of pathogens from highly touched objects. Naturally occurring halloysite clay nanotubes (HNTs) have shown to be ideal particles for polymer reinforcement, time-release drug delivery, nano-reactor synthesis, and as substrate material for nanostructured coatings. This research demonstrates the feasibility of a novel method for coating HNTs with metals for antibacterial applications. The first ever ability to coat HNTs through electrolysis was developed for customizable and multi-functional antibacterial nanoparticle platforms. HNTs were investigated as substrate for the deposition of copper (Cu) and silver (Ag) metal nanoparticles through electrochemical syntheses, and as a platform for nano-structured antibacterial polymer composites. Characterization of interfacial and material properties demonstrated the feasibility of electrolysis as a new efficient and replicable nano-scale surface modification route. Methods of encapsulating HNTs in nanofibers, three-dimensional printer filaments, and multifunctional polymer rubbers were also realized. The nanofabrication methods, nanoparticles, and polymer composites created in this work were novel, scalable, easy-to-replicate, and displayed antibacterial features with tunable properties.

  7. Nanostructured Energetic Materials with Sol-Gel Methods

    SciTech Connect

    Gash, A; Satcher, J; Simpson, R; Clapsaddle, B

    2003-11-25

    The utilization of sol-gel chemical methodology to prepare nanostructured energetic materials as well as the concepts of nanoenergetics is described. The preparation and characterization of two totally different compositions is detailed. In one example, nanostructured aerogel and xerogel composites of sol-gel iron (III) oxide and ultra fine grained aluminum (UFG Al) are prepared, characterized, and compared to a conventional micron-sized Fe{sub 2}O{sub 3}/Al thermite. The exquisite degree of mixing and intimate nanostructuring of this material is illustrated using transmission and scanning electron microscopies (TEM and SEM). The nanocomposite material has markedly different energy release (burn rate) and thermal properties compared to the conventional composite, results of which will be discussed. Small-scale safety characterization was performed aerogels and xerogels of the nanostructured thermite. The second nanostructured energetic material consists of a nanostructured hydrocarbon resin fuel network with fine ammonium perchlorate (NH{sub 4}ClO{sub 4}) oxidizer present.

  8. Processes for fabricating composite reinforced material

    DOEpatents

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2015-11-24

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  9. Computational Materials: Modeling and Simulation of Nanostructured Materials and Systems

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Hinkley, Jeffrey A.

    2003-01-01

    The paper provides details on the structure and implementation of the Computational Materials program at the NASA Langley Research Center. Examples are given that illustrate the suggested approaches to predicting the behavior and influencing the design of nanostructured materials such as high-performance polymers, composites, and nanotube-reinforced polymers. Primary simulation and measurement methods applicable to multi-scale modeling are outlined. Key challenges including verification and validation of models are highlighted and discussed within the context of NASA's broad mission objectives.

  10. Copper-micrometer-sized diamond nanostructured composites

    NASA Astrophysics Data System (ADS)

    Nunes, D.; Livramento, V.; Shohoji, N.; Fernandes, H.; Silva, C.; Correia, J. B.; Carvalho, P. A.

    2011-12-01

    Reinforcement of a copper matrix with diamond enables tailoring the properties demanded for thermal management applications at high temperature, such as the ones required for heat sink materials in low activated nuclear fusion reactors. For an optimum compromise between thermal conductivity and mechanical properties, a novel approach based on multiscale diamond dispersions is proposed: a Cu-nanodiamond composite produced by milling is used as a nanostructured matrix for further dispersion of micrometer-sized diamond (μDiamond). A series of Cu-nanodiamond mixtures have been milled to establish a suitable nanodiamond fraction. A refined matrix with homogeneously dispersed nanoparticles was obtained with 4 at.% μDiamond for posterior mixture with microdiamond and subsequent consolidation. Preliminary consolidation by hot extrusion of a mixture of pure copper and μDiamond has been carried out to define optimal processing parameters. The materials produced were characterized by x-ray diffraction, scanning and transmission electron microscopy and microhardness measurements.

  11. Nanostructured Materials: Symthesis in Supercritical Fluids

    SciTech Connect

    Lin, Yuehe; Ye, Xiangrong; Wai, Chien M.

    2009-03-24

    This chapter summarizes the recent developent of synthesis and characterization of nanostructured materials synthesized in supercritical fluids. Nanocomposite catalysts such as Pt and Pd on carbon nanotube support have been synthesized and used for fuel cell applications.

  12. Nanostructured Diclofenac Sodium Releasing Material

    NASA Astrophysics Data System (ADS)

    Nikkola, L.; Vapalahti, K.; Harlin, A.; Seppälä, J.; Ashammakhi, N.

    2008-02-01

    Various techniques have been developed to produce second generation biomaterials for tissue repair. These include extrusion, molding, salt leaching, spinning etc, but success in regenerating tissues has been limited. It is important to develop porous material, yet with a fibrous structure for it to be biomimetic. To mimic biological tissues, the extra-cellular matrix usually contains fibers in nano scale. To produce nanostructures, self-assembly or electrospinning can be used. Adding a drug release function to such a material may advance applications further for use in controlled tissue repair. This turns the resulting device into a multifunctional porous, fibrous structure to support cells and drug releasing properties in order to control tissue reactions. A bioabsorbable poly(ɛ-caprolactone-co-D,L lactide) 95/5 (PCL) was made into diluted solution using a solvent, to which was added 2w-% of diclofenac sodium (DS). Nano-fibers were made by electrospinning onto substrate. Microstructure of the resulting nanomat was studied using SEM and drug release profiles with UV/VIS spectroscopy. Thickness of the electrospun nanomat was about 2 mm. SEM analysis showed that polymeric nano-fibers containing drug particles form a highly interconnected porous nano structure. Average diameter of the nano-fibers was 130 nm. There was a high burst peak in drug release, which decreased to low levels after one day. The used polymer has slow a degradation rate and though the nanomat was highly porous with a large surface area, drug release rate is slow. It is feasible to develop a nano-fibrous porous structure of bioabsorbable polymer, which is loaded with test drug. Drug release is targeted at improving the properties of biomaterial for use in controlled tissue repair and regeneration.

  13. Nanostructured Materials for Renewable Energy

    SciTech Connect

    2009-11-01

    This factsheet describes a research project whose overall objective is to advance the fundamental understanding of novel photoelectronic organic device structures integrated with inorganic nanostructures, while also expanding the general field of nanomaterials for renewable energy devices and systems.

  14. Silk fibroin nanostructured materials for biomedical applications

    NASA Astrophysics Data System (ADS)

    Mitropoulos, Alexander N.

    Nanostructured biopolymers have proven to be promising to develop novel biomedical applications where forming structures at the nanoscale normally occurs by self-assembly. However, synthesizing these structures can also occur by inducing materials to transition into other forms by adding chemical cross-linkers, changing pH, or changing ionic composition. Understanding the generation of nanostructures in fluid environments, such as liquid organic solvents or supercritical fluids, has not been thoroughly examined, particularly those that are based on protein-based block-copolymers. Here, we examine the transformation of reconstituted silk fibroin, which has emerged as a promising biopolymer due to its biocompatibility, biodegradability, and ease of functionalization, into submicron spheres and gel networks which offer applications in tissue engineering and advanced sensors. Two types of gel networks, hydrogels and aerogels, have small pores and large surface areas that are defined by their structure. We design and analyze silk nanoparticle formation using a microfluidic device while offering an application for drug delivery. Additionally, we provide a model and characterize hydrogel formation from micelles to nanoparticles, while investigating cellular response to the hydrogel in an in vitro cell culture model. Lastly, we provide a second model of nanofiber formation during near-critical and supercritical drying and characterize the silk fibroin properties at different drying pressures which, when acting as a stabilizing matrix, shows to improve the activity of entrapped enzymes dried at different pressures. This work has created new nanostructured silk fibroin forms to benefit biomedical applications that could be applied to other fibrous proteins.

  15. Synthesis and processing of nanostructured materials

    SciTech Connect

    Siegel, R.W.

    1992-12-01

    Significant and growing interest is being exhibited in the novel and enhanced properties of nanostructured materials. These materials, with their constituent phase or grain structures modulated on a length scale less than 100 nm, are artificially synthesized by a wide variety of physical, chemical, and mechanical methods. In this NATO Advanced Study Institute, where mechanical behavior is emphasized, nanostructured materials with modulation dimensionalities from one (multilayers) to three (nanophase materials) are mainly considered. No attempt is made in this review to cover in detail all of the diverse methods available for the synthesis of nanostructured materials. Rather, the basic principles involved in their synthesis are discussed in terms of the special properties sought using examples of particular synthesis and processing methodologies. Some examples of the property changes that can result from one of these methods, cluster assembly of nanophase materials, are presented.

  16. Composite Materials

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Composites are lighter and stronger than metals. Aramid fibers like Kevlar and Nomex were developed by DuPont Corporation and can be combined in a honeycomb structure which can give an airplane a light, tough structure. Composites can be molded into many aerodynamic shapes eliminating rivets and fasteners. Langley Research Center has tested composites for both aerospace and non-aerospace applications. They are also used in boat hulls, military shelters, etc.

  17. Shockwave Consolidation of Nanostructured Thermoelectric Materials

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.; Taylor, Patrick; Nemir, David

    2014-01-01

    Nanotechnology based thermoelectric materials are considered attractive for developing highly efficient thermoelectric devices. Nano-structured thermoelectric materials are predicted to offer higher ZT over bulk materials by reducing thermal conductivity and increasing electrical conductivity. Consolidation of nano-structured powders into dense materials without losing nanostructure is essential towards practical device development. Using the gas atomization process, amorphous nano-structured powders were produced. Shockwave consolidation is accomplished by surrounding the nanopowder-containing tube with explosives and then detonating. The resulting shock wave causes rapid fusing of the powders without the melt and subsequent grain growth. We have been successful in generating consolidated nano-structured bismuth telluride alloy powders by using the shockwave technique. Using these consolidated materials, several types of thermoelectric power generating devices have been developed. Shockwave consolidation is anticipated to generate large quantities of nanostructred materials expeditiously and cost effectively. In this paper, the technique of shockwave consolidation will be presented followed by Seebeck Coefficient and thermal conductivity measurements of consolidated materials. Preliminary results indicate a substantial increase in electrical conductivity due to shockwave consolidation technique.

  18. Nanostructured metal-polyaniline composites

    DOEpatents

    Wang, Hsing-Lin; Li, Wenguang; Bailey, James A.; Gao, Yuan

    2010-08-31

    Metal-polyaniline (PANI) composites are provided together with a process of preparing such composites by an electrodeless process. The metal of the composite can have nanoscale structural features and the composites can be used in applications such as catalysis for hydrogenation reactions and for analytical detection methods employing SERS.

  19. Three-Dimensional Composite Nanostructures for Lean NOx Emission Control

    SciTech Connect

    Gao, Pu-Xian

    2013-07-31

    This final report to the Department of Energy (DOE) and National Energy Technology Laboratory (NETL) for DE-EE0000210 covers the period from October 1, 2009 to July 31, 2013. Under this project, DOE awarded UConn about $1,248,242 to conduct the research and development on a new class of 3D composite nanostructure based catalysts for lean NOx emission control. Much of the material presented here has already been submitted to DOE/NETL in quarterly technical reports. In this project, through a scalable solution process, we have successfully fabricated a new class of catalytic reactors, i.e., the composite nanostructure array (nano-array) based catalytic converters. These nanocatalysts, distinct from traditional powder washcoat based catalytic converters, directly integrate monolithic substrates together with nanostructures with well-defined size and shape during the scalable hydrothermal process. The new monolithic nanocatalysts are demonstrated to be able to save raw materials including Pt-group metals and support metal oxides by an order of magnitude, while perform well at various oxidation (e.g., CO oxidation and NO oxidation) and reduction reactions (H{sub 2} reduction of NOx) involved in the lean NOx emissions. The size, shape and arrangement of the composite nanostructures within the monolithic substrates are found to be the key in enabling the drastically reduced materials usage while maintaining the good catalytic reactivity in the enabled devices. The further understanding of the reaction kinetics associated with the unique mass transport and surface chemistry behind is needed for further optimizing the design and fabrication of good nanostructure array based catalytic converters. On the other hand, the high temperature stability, hydrothermal aging stability, as well as S-poisoning resistance have been investigated in this project on the nanocatalysts, which revealed promising results toward good chemical and mechanical robustness, as well as S

  20. Dye-sensitized composite semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Tennakone, K.; Bandaranayake, P. K. M.; Jayaweera, P. V. V.; Konno, A.; Kumara, G. R. R. A.

    2002-04-01

    Understanding of the charge transport and recombination mechanisms of dye-sensitized solar cells based on semiconductor nanostructures is essential for the improvement of their performance. A great deal of information on these systems have been obtained from studies on a single material (mostly TiO 2 and to a lesser extent ZnO and SnO 2). We have conducted extensive measurements on composite dye-sensitized nanosturctures and found that the composite systems possess unusual properties. Dye-sensitized photoelectrochemical cells made from nanocrystalline films of some materials (e.g., SnO 2) yield comparatively small open-circuit voltages and energy and quantum conversion efficiencies, despite excellent dye-semiconductor interaction. However, on deposition of ultra-thin shells of insulators or high band gap semiconductors on the crystallites, a dramatic increase in the above parameters is observed. Outer shells were found to have insignificant or in most cases a negative effect on TiO 2 films. We explain the above findings on the basis of vast differences in the leakage rates of trapped electrons in different materials which is sensitive to the effective electron mass. Electrons injected to the conduction band in dye-sensitization enter into shallow traps from which they get thermally reemitted to the conduction band. The building up of the electron quasi-fermi level and transport depends on this process. The spread of the hydrogenic wave function of a trapped electron increases inverse exponentially with the effective mass so that the electron leakage and their recombination with acceptors ‘outside’ become severe when the crystallite size is comparable to the Bohr radius of the trapped electron. Such recombinations are effectively suppressed by deposition of thin films on the crystallites. Excited dye molecules anchored to the outer shell injects electrons to the conduction band via tunneling.

  1. Supercritical carbon dioxide approach to nanostructured materials

    NASA Astrophysics Data System (ADS)

    Ye, Xiang-Rong

    Supercritical fluid technology is a novel and emerging strategy to generate nanomaterials in small areas, within high-aspect-ratio structures, on complicated surfaces and poor wettable substrates with high uniformity, high homogeneity and minimum environmental problems. In this dissertation, several strategies were developed for thin film deposition and nanocomposite fabrication. In developing supercritical fluid immersion deposition (SFID), supercritical or near supercritical CO2 was used as a new solvent for immersion deposition, a galvanic displacement process traditionally carried out in aqueous HF solutions containing metal ions, to selectively develop Pd, Cu, Ag and other metal films on featured and non-featured Si substrates. Annealing of thin palladium films deposited by SFID can lead to the formation of palladium silicide in small features on Si substrates. Deposition of metal films on germanium substrates was also achieved through SFID. Through hydrogen reduction of metal-beta-diketone complexes in supercritical CO2, a rapid, convenient and environmentally benign approach has been developed to synthesize a variety of nanostructured materials: (1) Metal (Pd, Ni and Cu) nanowires and nanorods sheathed within multi-walled carbon nanotube (MWCNT) templates; (2) nanoparticles of palladium, rhodium and ruthenium decorated onto functionalized MWCNTs. These highly dispersed nanoparticles are expected to exhibit promising catalytic properties for a variety of chemical or electrochemical reactions; (3) Cu, Pd or Cu-Pd alloy nanocrystals deposited onto SiO2 nanowires (NWs), SiO2 microfibers, or SiC NWs. Different types of nanostructures were achieved, including nanocrystal-NW, spherical aggregation-NW, shell-NW composites and "mesoporous" metals supported by the framework of NWs.

  2. Engineering hybrid nanostructures of active materials: Applications as electrode materials in lithium ion rechargeable batteries

    NASA Astrophysics Data System (ADS)

    Huang, Huan

    Aiming to significantly improve the electrochemical properties of electroactive materials for lithium ion batteries, three novel hybrid nanostructures were developed in this thesis. These include nanostructure A: V2O 5 coated on polymer electrolyte-grafted carbon black, nanostructure B: electrode materials incorporated into an electronically conductive carbon web, and nanostructure C: electrode materials dispersed in a conductive porous carbon matrix. Nanocomposites possessing nanostructure A are fast electronic and ionic transport materials. The improved kinetic properties are due to the incorporated carbon core and the grafted polymer electrolyte in the unique structure. The V2O5 xerogel coated polymer electrolyte-grafted carbon blacks, or V2O5/C-PEG, can reach a capacity as high as 320 mAh/g, and exhibit outstanding rate sustainability (e.g. 190 mAh/g at 14C). This class of nanostructured composites is promising for high power/current applications. Nanostructure B was extremely successful when applied to very poorly conductive active materials, such as LiFePO4 and Li3V 2(PO4)3. In this nanostructure, the web-like carbon framework not only supplies a facile electron transport path, but also provides excellent electronic contact between carbon and the insulating active materials. At room temperature, the LiFePO4/C nanocomposite successfully reaches almost full capacity, along with greatly improved rate sustainability and excellent cycling stability. At elevated temperatures (e.g. 40°C and 60°C), the full capacity is readily accessible over a wide rate range, even at a very fast rate of 2C or 5C. The Li3V2(PO4) 3/C nanocomposite can extract all three lithium in the formula at a rate of 1C, resulting in a high capacity of 200 mAh/g. Therefore, through designing hybrid nanostructures with nanostructure B, we can make insulating active materials into good cathode materials. Nanostructure C was employed for Sn-based anode materials, in order to improve their cycling

  3. Nanostructured materials in the food industry.

    PubMed

    Augustin, Mary Ann; Sanguansri, Peerasak

    2009-01-01

    Nanotechnology involves the application, production, and processing of materials at the nanometer scale. Biological- and physical-inspired approaches, using both conventional and innovative food processing technologies to manipulate matter at this scale, provide the food industry with materials with new functionalities. Understanding the assembly behavior of native and modified food components is essential in developing nanostructured materials. Functionalized nanostructured materials are finding applications in many sectors of the food industry, including novel nanosensors, new packaging materials with improved mechanical and barrier properties, and efficient and targeted nutrient delivery systems. An improved understanding of the benefits and the risks of the technology based on sound scientific data will help gain the acceptance of nanotechnology by the food industry. New horizons for nanotechnology in food science may be achieved by further research on nanoscale structures and methods to control interactions between single molecules.

  4. Superhydrophobicity on nanostructured porous hydrophilic material

    NASA Astrophysics Data System (ADS)

    Jiang, Hong-Ren; Chan, Deng-Chi

    2016-04-01

    By applying laser oxidation, ablation, and plasma treatment to modify a surface of polydimethylsiloxane, we show that creating hydrophobic sites on an originally superhydrophilic nanostructured porous surface greatly changes the wetting properties of the surface. The modified surface may even become superhydrophobic while the ratio of added hydrophobic site to the surface is relatively low. The relation between the contact angles and the effect of hydrophobic sites is further tested in blade scraping method and a similar result is also obtained. This method to achieve superhydrophobicity on the hydrophilic nanostructured porous material may open possibilities for achieving superhydrophobicity and enable functional superhydrophobic surfaces with heterogeneous components.

  5. UV fluorescence enhancement from nanostructured aluminum materials

    NASA Astrophysics Data System (ADS)

    Montanari, Danielle E.; Dean, Nathan; Poston, Pete E.; Blair, Steve; Harris, Joel M.

    2016-09-01

    Interest in label-free detection of biomolecules has given rise to the need for UV plasmonic materials. DNA bases and amino acid residues have electronic resonances in the UV which allow for sensitive detection of these species by surface-enhanced UV fluorescence spectroscopy. Electrochemical roughening has been used extensively to generate plasmonically-active metal surfaces that produce localized enhancement of excitation and emission of electromagnetic radiation from surface-bound molecules. Electrochemically roughened gold and silver surfaces produce enhancement in the visible and near-IR regions, but to the best of our knowledge, application of this technique for producing UV-enhancing substrates has not been reported. Using electropolishing of aluminum, we are able to generate nanostructured surfaces that produce enhanced spectroscopic detection of molecules in the UV. Aluminum is a natural choice for substrate composition as it exhibits a relatively large quality factor in the UV. We have fabricated electropolished aluminum films with nanometer scale roughness and have studied UV-excited fluorescence enhancement from submonolayer coverage of tryptophan on these substrates using a UV-laser based spectrometer. Quantitative dosing by dip-coating was used to deposit known surface concentrations of the aromatic amino acid tryptophan, so that fluorescence enhancement could be evaluated. Compared to a dielectric substrate (surface-oxidized silicon), we observe a 180-fold enhancement in the total fluorescence emitted by tryptophan on electropolished aluminum under photobleaching conditions, allowing detection of sub-monolayer coverages of molecules essential for development of biosensor technologies.

  6. Giant magnetoresistive nanostructured materials by electrodeposition

    NASA Astrophysics Data System (ADS)

    Myung, No Sang

    NiFe/Cu and CoFe/Cu multilayers and NiFe compositional modulated alloys (CMA) electrodeposited by newly developed flow-through electrochemical reactor. Sub-micron (Ni)Cu and nano-size (CoFe)Cu granular alloys have been electrodeposited by magneto-electrodeposition method. These two methods eliminate the problems confronted by conventional methods and provide a new direction in fabrication of nanostructured materials by electrodeposition. Prior to fabrication of GMR materials, electrodeposition kinetics of individual metals (Co, NiFe, Cu) were studied. In Co electrodeposition and dissolution from sulfate bath, substrates have a great impact on the initial growth mode of film. On polycrystalline platinum metal, cobalt film grew in hemispherical shape (nodule) where it grew in right conical shape on amorphous glass carbon. In NiFe alloys electrodeposition, the effects of applied current density, solution composition, substrate and solution hydrodynamics on current efficiency, film composition, crystal structure, corrosion resistant, and magnetic properties of NiFe alloys from all-chloride and citrate-sulfate-chloride bath have been studied. Citrate ions enhance the anomalous codeposition phenomena in NiFe electrodeposition. In crystal structure studies on electrodeposited. NiFe, the narrow mixed phase solid region was noted around 50% Fe. In addition, the smallest grain size were also observed in that region. In corrosion studies, the maximum corrosion resistance was observed at 50% Fe in naturally aerated 0.5 M NaCl. In Ni/Cu and Co/Cu multilayers by single bath technique, the optimum deposition potential ranges of pure copper and nickel (cobalt) were determined to minimize copper codeposition during nickel (cobalt) deposition and to minimize cobalt dissolution during copper deposition. Well defined laminated NiFe/Cu and CoFe/Cu multilayers and NiFe compositional modulated alloys (CMA) were successfully electrodeposited by utilizing flow-through electrochemical

  7. Screen-printed nanostructured composites as thermal interface materials for insulated gate bipolar transistors heat dissipation applications

    NASA Astrophysics Data System (ADS)

    Chang, Tien-Chan; Fuh, Yiin-Kuen; Lee, Rui-Zhong; Li-Yuan, Liu; Lee, Yueh-Mu

    2016-10-01

    Thermal interface materials (TIMs) are of crucial importance in enhancing heat transfer and minimizing exceedingly high temperatures in high-density electronics. TIMs functionally aim to reduce the microscale crevices by penetrating the gap between the contacting rigid surfaces. We prepared silver nanoparticles (SNPs) and single-wall carbon nanotubes (SWCNTs)-based nanocomposites with graphite nanoplatelets (GNPs) by using a screen printing technique for conformal spreading of SNPs and SWCNTs with various weight-loading ratios on top of a layer containing the GNPs and measured its thermal conductivity and electrical conductivities in both through-plane and in-plane directions. In particular, the 10% SNPs enhanced TIMs showed highly anisotropic behavior in both electrical and thermal conductivities, viz., in-plane electrical conductivity exceeds its through-plane counterpart by three orders of magnitude, the highest in-plane electrical conductivity was 7.85 S/cm, and through-plane electrical conductivity was 0.00287 S/cm. Similarly, anisotropic behavior was found for the in-plane thermal conductivity ˜8.4 W/mK and through-plane thermal conductivity ˜0.35943 W/mK. In addition, scanning electron microscopy (SEM) was performed to reveal the typical morphology and elements' existence of screen-printed TIMs. The proposed TIMs were put into the actual 15-kW converter to test the thermal management performance.

  8. Gas sensors based on nanostructured materials.

    PubMed

    Jiménez-Cadena, Giselle; Riu, Jordi; Rius, F Xavier

    2007-11-01

    Gas detection is important for controlling industrial and vehicle emissions, household security and environmental monitoring. In recent decades many devices have been developed for detecting CO(2), CO, SO(2), O(2), O(3), H(2), Ar, N(2), NH(3), H(2)O and several organic vapours. However, the low selectivity or the high operation temperatures required when most gas sensors are used have prompted the study of new materials and the new properties that come about from using traditional materials in a nanostructured mode. In this paper, we have reviewed the main research studies that have been made of gas sensors that use nanomaterials. The main quality characteristics of these new sensing devices have enabled us to make a critical review of the possible advantages and drawbacks of these nanostructured material-based sensors.

  9. Nanostructure studies of strongly correlated materials.

    PubMed

    Wei, Jiang; Natelson, Douglas

    2011-09-01

    Strongly correlated materials exhibit an amazing variety of phenomena, including metal-insulator transitions, colossal magnetoresistance, and high temperature superconductivity, as strong electron-electron and electron-phonon couplings lead to competing correlated ground states. Recently, researchers have begun to apply nanostructure-based techniques to this class of materials, examining electronic transport properties on previously inaccessible length scales, and applying perturbations to drive systems out of equilibrium. We review progress in this area, particularly emphasizing work in transition metal oxides (Fe(3)O(4), VO(2)), manganites, and high temperature cuprate superconductors. We conclude that such nanostructure-based studies have strong potential to reveal new information about the rich physics at work in these materials.

  10. Could Nano-Structured Materials Enable the Improved Pressure Vessels for Deep Atmospheric Probes?

    NASA Technical Reports Server (NTRS)

    Srivastava, D.; Fuentes, A.; Bienstock, B.; Arnold, J. O.

    2005-01-01

    A viewgraph presentation on the use of Nano-Structured Materials to enable pressure vessel structures for deep atmospheric probes is shown. The topics include: 1) High Temperature/Pressure in Key X-Environments; 2) The Case for Use of Nano-Structured Materials Pressure Vessel Design; 3) Carbon based Nanomaterials; 4) Nanotube production & purification; 5) Nanomechanics of Carbon Nanotubes; 6) CNT-composites: Example (Polymer); 7) Effect of Loading sequence on Composite with 8% by volume; 8) Models for Particulate Reinforced Composites; 9) Fullerene/Ti Composite for High Strength-Insulating Layer; 10) Fullerene/Epoxy Composite for High Strength-Insulating Layer; 11) Models for Continuous Fiber Reinforced Composites; 12) Tensile Strength for Discontinuous Fiber Composite; 13) Ti + SWNT Composites: Thermal/Mechanical; 14) Ti + SWNT Composites: Tensile Strength; and 15) Nano-structured Shell for Pressure Vessels.

  11. Aerogel Derived Nanostructured Thermoelectric Materials

    SciTech Connect

    Wendell E Rhine, PI; Dong, Wenting; Greg Caggiano, PM

    2010-10-08

    America’s dependence on foreign sources for fuel represents a economic and security threat for the country. These non renewable resources are depleting, and the effects of pollutants from fuels such as oil are reaching a problematic that affects the global community. Solar concentration power (SCP) production systems offer the opportunity to harness one of the United States’ most under utilized natural resources; sunlight. While commercialization of this technology is increasing, in order to become a significant source of electricity production in the United States the costs of deploying and operating SCP plants must be further reduced. Parabolic Trough SCP technologies are close to meeting energy production cost levels that would raise interest in the technology and help accelerate its adoption as a method to produce a significant portion of the Country’s electric power needs. During this program, Aspen Aerogels will develop a transparent aerogel insulation that can replace the costly vacuum insulation systems that are currently used in parabolic trough designs. During the Phase I program, Aspen Aerogels will optimize the optical and thermal properties of aerogel to meet the needs of this application. These properties will be tested, and the results will be used to model the performance of a parabolic trough HCE system which uses this novel material in place of vacuum. During the Phase II program, Aspen Aerogels will scale up this technology. Together with industry partners, Aspen Aerogels will build and test a prototype Heat Collection Element that is insulated with the novel transparent aerogel material. This new device will find use in parabolic trough SCP applications.

  12. Thermoelectric Properties of Solution Synthesized Nanostructured Materials.

    PubMed

    Finefrock, Scott W; Yang, Haoran; Fang, Haiyu; Wu, Yue

    2015-01-01

    Thermoelectric nanocomposites made by solution synthesis and compression of nanostructured chalcogenides could potentially be low-cost, scalable alternatives to traditional solid-state synthesized materials. We review the progress in this field by comparing the power factor and/or the thermoelectric figure of merit, ZT, of four classes of materials: (Bi,Sb)2(Te,Se)3, PbTe, ternary and quaternary copper chalcogenides, and silver chalcogenides. We also discuss the thermal conductivity reduction associated with multiphased nanocomposites. The ZT of the best solution synthesized materials are, in several cases, shown to be equal to or greater than the corresponding bulk materials despite the generally reduced mobility associated with solution synthesized nanocomposites. For the solution synthesized materials with the highest performance, the synthesis and processing conditions are summarized to provide guidance for future work.

  13. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R. G.; Wiberley, S. E.

    1985-01-01

    Various topics relating to composite structural materials for use in aircraft structures are discussed. The mechanical properties of high performance carbon fibers, carbon fiber-epoxy interface bonds, composite fractures, residual stress in high modulus and high strength carbon fibers, fatigue in composite materials, and the mechanical properties of polymeric matrix composite laminates are among the topics discussed.

  14. Metal-polymer composites comprising nanostructures and applications thereof

    DOEpatents

    Wang, Hsing-Lin [Los Alamos, NM; Jeon, Sea Ho [Dracut, MA; Mack, Nathan H [Los Alamos, NM

    2012-04-03

    Metal-polymer composites, and methods of making and use thereof, said composites comprising a thermally-cured dense polyaniline substrate; an acid dopant; and, metal nanostructure deposits wherein the deposits have a morphology dependent upon the acid dopant.

  15. Metal-polymer composites comprising nanostructures and applications thereof

    DOEpatents

    Wang, Hsing-Lin; Jeon, Sea Ho; Mack, Nathan H.

    2011-08-02

    Metal-polymer composites, and methods of making and use thereof, said composites comprising a thermally-cured dense polyaniline substrate; an acid dopant; and, metal nanostructure deposits wherein the deposits have a morphology dependent upon the acid dopant.

  16. Dissociation of formaldehyde in nanostructured carbon materials

    NASA Astrophysics Data System (ADS)

    George, Aaron; Santiso, Erik; Buongiorno Nardelli, Marco; Gubbins, K. E.

    2004-11-01

    Chemical reactions are frequently carried out in nano-structured media, such as micellar or colloidal solutions, nano-porous media, hydrogels or organogels, or in systems involving nano-particles. Nanostructured environments have been shown to enhance reaction rates through a variety of catalytic effects, such as high surface area, interactions with the nano-structure or confinement. However, at present there is little understanding of the role of the nano-structured material in such reactions and the mechanisms involved are subject of ongoing scientific debate. In this work, we have used state-of-the-art electronic structure techniques to study the prototypical example of the reaction of formaldehyde dissociation (H_2CO arrow H2 + CO) within various configurations of a graphitic pore. Using the Nudged Elastic Band (NEB) method for transition states analysis, we have found that the activation en ergy of the dissociation can be influenced by the presence of a graphitic pore. In particular, while a graphene surface reduces the activation barrier for the reaction, this catalytic effect is enhanced by the presence of two planar sheets, which mimic the geometry of a nano-pore. This can likewise induce a decrease of the activation energy, thus making the reaction more energetically favor able. The reaction activation energy has a dependence on the width of the pore (distance between sheets). A decrease is seen to a point of decreasing width, then a change in the favorable reaction path occurs. It is also found the presence of a vacancy can drastically change the reaction path. These conclusions will be discussed in terms of the charge transfer mechanism seen in the catalytic process.

  17. Nanostructured Materials Development for Space Power

    NASA Technical Reports Server (NTRS)

    Raffaelle, Ryne P.; Landi, B. J.; Elich, J. B.; Gennett, T.; Castro, S. L.; Bailey, Sheila G.; Hepp, Aloysius F.

    2003-01-01

    There have been many recent advances in the use of nanostructured materials for space power applications. In particular, the use of high purity single wall nanotubes holds promise for a variety of generation and storage devices including: thin film lithium ion batteries, microelectronic proton exchange membrane (PEM) fuel cells, polymeric thin film solar cells, and thermionic power supplies is presented. Semiconducting quantum dots alone and in conjunction with carbon nanotubes are also being investigated for possible use in high efficiency photovoltaic solar cells. This paper will review some of the work being done at RIT in conjunction with the NASA Glenn Research Center to utilize nanomaterials in space power devices.

  18. Mechanical properties of nanostructure of biological materials

    NASA Astrophysics Data System (ADS)

    Ji, Baohua; Gao, Huajian

    2004-09-01

    Natural biological materials such as bone, teeth and nacre are nanocomposites of protein and mineral with superior strength. It is quite a marvel that nature produces hard and tough materials out of protein as soft as human skin and mineral as brittle as classroom chalk. What are the secrets of nature? Can we learn from this to produce bio-inspired materials in the laboratory? These questions have motivated us to investigate the mechanics of protein-mineral nanocomposite structure. Large aspect ratios and a staggered alignment of mineral platelets are found to be the key factors contributing to the large stiffness of biomaterials. A tension-shear chain (TSC) model of biological nanostructure reveals that the strength of biomaterials hinges upon optimizing the tensile strength of the mineral crystals. As the size of the mineral crystals is reduced to nanoscale, they become insensitive to flaws with strength approaching the theoretical strength of atomic bonds. The optimized tensile strength of mineral crystals thus allows a large amount of fracture energy to be dissipated in protein via shear deformation and consequently enhances the fracture toughness of biocomposites. We derive viscoelastic properties of the protein-mineral nanostructure and show that the toughness of biocomposite can be further enhanced by the viscoelastic properties of protein.

  19. Thermionic Converters Based on Nanostructured Carbon Materials

    NASA Astrophysics Data System (ADS)

    Koeck, Franz A. M.; Wang, Yunyu; Nemanich, Robert J.

    2006-01-01

    Thermionic energy converters are based on electron emission through thermal excitation and collection where the thermal energy is directly converted into electrical power. Conventional thermionic energy converters based on emission from planar metal emitters have been limited due to space charge. This paper presents a novel approach to thermionic energy conversion by focusing on nanostructured carbon materials, sulfur doped nanocrystalline diamond and carbon nanotube films as emitters. These materials exhibit intrinsic field enhancement which can be exploited in lowering the emission barrier, i.e. the effective work function. Moreover, emission from these materials is described in terms of emission sites as a result of a non-uniform spatial distribution of the field enhancement factor. This phenomenon can prove advantageous in a converter configuration to mitigate space charge effects by reducing the transit time of electrons in the gap due to an accelerated charge carrier transport.

  20. Composite material dosimeters

    DOEpatents

    Miller, Steven D.

    1996-01-01

    The present invention is a composite material containing a mix of dosimeter material powder and a polymer powder wherein the polymer is transparent to the photon emission of the dosimeter material powder. By mixing dosimeter material powder with polymer powder, less dosimeter material is needed compared to a monolithic dosimeter material chip. Interrogation is done with excitation by visible light.

  1. Nanostructured energetic materials derived from sol-gel chemistry

    SciTech Connect

    Simpson, R L; Tillotson, T M; Hrubesh, L W; Gash, A E

    2000-03-15

    Initiation and detonation properties are dramatically affected by an energetic material's microstructural properties. Sol-gel chemistry allows intimacy of mixing to be controlled and dramatically improved over existing methodologies. One material goal is to create very high power energetic materials which also have high energy densities. Using sol-gel chemistry we have made a nanostructured composite energetic material. Here a solid skeleton of fuel, based on resorcinol-formaldehyde, has nanocrystalline ammonium perchlorate, the oxidizer, trapped within its pores. At optimum stoichiometry it has approximately the energy density of HMX. Transmission electron microscopy indicated no ammonium perchlorate crystallites larger than 20 nm while near-edge soft x-ray absorption microscopy showed that nitrogen was uniformly distributed, at least on the scale of less than 80 nm. Small-angle neutron scattering studies were conducted on the material. Those results were consistent with historical ones for this class of nanostructured materials. The average skeletal primary particle size was on the order of 2.7 nm, while the nanocomposite showed the growth of small 1 nm size crystals of ammonium perchlorate with some clustering to form particles greater than 10 nm.

  2. Nanostructured materials for applications in heterogeneous catalysis.

    PubMed

    Zaera, Francisco

    2013-04-07

    In this review, a brief survey is offered on the main nanotechnology synthetic approaches available to heterogeneous catalysis, and a few examples are provided of their usefulness for such applications. We start by discussing the use of colloidal, reverse micelle, and dendrimer chemistry in the production of active metal and metal oxide nanoparticles with well-defined sizes, shapes, and compositions, as a way to control the surface atomic ensembles available for selective catalysis. Next we introduce the use of sol-gel and atomic layer deposition chemistry for the production and modification of high-surface-area supports and active phases. Reference is then made to the more complex active sites that can be created or carved on such supports by using organic structure-directing agents. We follow with an examination of the ability to achieve multiple functionality in catalysis via the design of dumbbells, core@shell, and other complex nanostructures. Finally, we consider the mixed molecular-nanostructure approach that can be used to develop more demanding catalytic sites, by derivatizing the surface of solids or tethering or immobilizing homogeneous catalysts or other chemical functionalities. We conclude with a personal and critical perspective on the importance of fully exploiting the synergies between nanotechnology and surface science to optimize the search for new catalysts and catalytic processes.

  3. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1983-01-01

    Transverse properties of fiber constituents in composites, fatigue in composite materials, matrix dominated properties of high performance composites, numerical investigation of moisture effects, numerical investigation of the micromechanics of composite fracture, advanced analysis methods, compact lug design, and the RP-1 and RP-2 sailplanes projects are discussed.

  4. Multifunctional nanostructured materials for multimodal cancer imaging and therapy.

    PubMed

    Liao, Jinfeng; Qi, Tingting; Chu, Bingyang; Peng, Jinrong; Luo, Feng; Qian, Zhiyong

    2014-01-01

    This paper reviews the recent research and development of multifunctional nanostructured materials for multimodal imaging and therapy. The biomedical applications for multifunctional imaging, diagnosis and therapy are discussed for several nanostructured materials such as polymeric nanoparticles, magnetic nanoparticles, gold nanomaterials, carbon materials, quantum dots and silica nanoparticles. Due to the unique features of nanostructured materials including the large surface area, structural diversity, multifunctionality, and long circulation time in blood, these materials have emerged as attractive preferences for optimized therapy. Multimodal imaging can be introduced to nanostructured materials for precise and fast diagnosis of cancer, which overcomes the shortcoming of single-imaging modality. Meanwhile, nanostructured materials can be also used to deliver therapeutic agents to the disease site in order to accomplish multimodal imaging and simultaneous diagnosis and therapy.

  5. Final Technical Progress Report NANOSTRUCTURED MAGNETIC MATERIALS

    SciTech Connect

    Charles M. Falco

    2012-09-13

    This report describes progress made during the final phase of our DOE-funded program on Nanostructured Magnetic Materials. This period was quite productive, resulting in the submission of three papers and presentation of three talks at international conferences and three seminars at research institutions. Our DOE-funded research efforts were directed toward studies of magnetism at surfaces and interfaces in high-quality, well-characterized materials prepared by Molecular Beam Epitaxy (MBE) and sputtering. We have an exceptionally well-equipped laboratory for these studies, with: Thin film preparation equipment; Characterization equipment; Equipment to study magnetic properties of surfaces and ultra-thin magnetic films and interfaces in multi-layers and superlattices.

  6. Supramolecular materials: Self-organized nanostructures

    SciTech Connect

    Stupp, S.I.; LeBonheur, V.; Walker, K.

    1997-04-18

    Miniaturized triblock copolymers have been found to self-assemble into nanostructures that are highly regular in size and shape. Mushroom-shaped supramolecular structures of about 200 kilodaltons form by crystallization of the chemically identical blocks and self-organize into films containing 100 or more layers stacked in a polar arrangement. The polar supramolecular material exhibits spontaneous second-harmonic generation from infrared to green photons and has an adhesive tape-like character with nonadhesive-hydrophobic and hydrophilic-sticky opposite surfaces. The films also have reasonable shear strength and adhere tenaciously to glass surfaces on one side only. The regular and finite size of the supramolecular units is believed to be mediated by repulsive forces among some of the segments in the triblock molecules. A large diversity of multifunctional materials could be formed from regular supramolecular units weighing hundreds of kilodaltons. 21 refs., 10 figs.

  7. Tough Composite Materials

    NASA Technical Reports Server (NTRS)

    Vosteen, L. F. (Compiler); Johnson, N. J. (Compiler); Teichman, L. A. (Compiler)

    1984-01-01

    Papers and working group summaries are presented which address composite material behavior and performance improvement. Topic areas include composite fracture toughness and impact characterization, constituent properties and interrelationships, and matrix synthesis and characterization.

  8. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1979-01-01

    Technology utilization of fiber reinforced composite materials is discussed in the areas of physical properties, and life prediction. Programs related to the Composite Aircraft Program are described in detail.

  9. Electrochemical synthesis of nanostructured materials for electrochemical energy conversion and storage.

    PubMed

    Li, Gao-Ren; Xu, Han; Lu, Xue-Feng; Feng, Jin-Xian; Tong, Ye-Xiang; Su, Cheng-Yong

    2013-05-21

    Electrochemical synthesis represents a highly efficient method for the fabrication of nanostructured energy materials, and various nanostructures, such as nanorods, nanowires, nanotubes, nanosheets, dendritic nanostructures, and composite nanostructures, can be easily fabricated with advantages of low cost, low synthetic temperature, high purity, simplicity, and environmental friendliness. The electrochemical synthesis, characterization, and application of electrochemical energy nanomaterials have advanced greatly in the past few decades, allowing an increasing understanding of nanostructure-property-performance relationships. Herein, we highlight some recent progress in the electrochemical synthesis of electrochemical energy materials with the assistance of additives and templates in solution or grafted onto metal or conductive polymer supports, with special attention to the effects on surface morphologies, structures and, more importantly, electrochemical performance. The methodology for preparing novel electrochemical energy nanomaterials and their potential applications has been summarized. Finally, we outline our personal perspectives on the electrochemical synthesis and applications of electrochemical energy nanomaterials.

  10. Nano-composite materials

    DOEpatents

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  11. Templated Electrodeposition of Highly Porous Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Yang, Han-Chang; Lim, Stephanie; Liu, Jiabin; Wu, Qian; Cheng, X. M.

    2011-03-01

    The fabrication of nanoporous materials has been of great interest for applications such as biosensors, photonic materials and energy storage. Compared to many other methods, the templated electrodeposition method is low cost, fast, and compatible with large-scale production. In this work, we developed a templated electrochemical deposition technique for fabricating highly ordered and highly porous nanostructured materials. The fabrication involves the following steps: self-assembly of monodispersed polystyrene spheres, electrochemical deposition of the desired materials, and sphere removal by a dissolution process. Deposition of Au and Ni layered metallic nanoporous structures were studied using different electrolytes at appropriate potentials. The pore size of the materials was tuned by using different sizes of template polystyrene spheres ranging from 50nm to 1000nm. Scanning electron microscopy images confirmed the highly ordered 3-dimensional hexagonal closed pack (hcp) structures in the samples. The templated electrochemical deposition technique provides a promising alternative approach to preparing highly porous anode materials for battery applications. Work supported by Bryn Mawr K/G fund for faculty research.

  12. Nanostructured reduced graphene oxide/Fe2O3 composite as a high-performance anode material for lithium ion batteries.

    PubMed

    Zhu, Xianjun; Zhu, Yanwu; Murali, Shanthi; Stoller, Meryl D; Ruoff, Rodney S

    2011-04-26

    Reduced graphene oxide/Fe(2)O(3) composite was prepared using a facile two-step synthesis by homogeneous precipitation and subsequent reduction of the G-O with hydrazine under microwave irradiation to yield reduced graphene oxide (RG-O) platelets decorated with Fe(2)O(3) nanoparticles. As an anode material for Li-ion batteries, the RG-O/Fe(2)O(3) composite exhibited discharge and charge capacities of 1693 and 1227 mAh/g, respectively, normalized to the mass of Fe(2)O(3) in the composite (and ∼1355 and 982 mAh/g, respectively, based on the total mass of the composite), with good cycling performance and rate capability. Characterization shows that the Fe(2)O(3) nanoparticles are uniformly distributed on the surface of the RG-O platelets in the composite. The total specific capacity of RG-O/Fe(2)O(3) is higher than the sum of pure RG-O and nanoparticle Fe(2)O(3), indicating a positive synergistic effect of RG-O and Fe(2)O(3) on the improvement of electrochemical performance. The synthesis approach presents a promising route for a large-scale production of RG-O platelet/metal oxide nanoparticle composites as electrode materials for Li-ion batteries.

  13. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1979-01-01

    A multifaceted program is described in which aeronautical, mechanical, and materials engineers interact to develop composite aircraft structures. Topics covered include: (1) the design of an advanced composite elevator and a proposed spar and rib assembly; (2) optimizing fiber orientation in the vicinity of heavily loaded joints; (3) failure mechanisms and delamination; (4) the construction of an ultralight sailplane; (5) computer-aided design; finite element analysis programs, preprocessor development, and array preprocessor for SPAR; (6) advanced analysis methods for composite structures; (7) ultrasonic nondestructive testing; (8) physical properties of epoxy resins and composites; (9) fatigue in composite materials, and (10) transverse thermal expansion of carbon/epoxy composites.

  14. Gold nanostructure materials in diabetes management

    NASA Astrophysics Data System (ADS)

    Si, Satyabrata; Pal, Arttatrana; Mohanta, Jagdeep; Sagar Satapathy, Smith

    2017-04-01

    Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia, and is now one of the most non-communicable diseases globally and can be lethal if not properly controlled. Prolonged exposure to chronic hyperglycemia, without proper management, can lead to various vascular complications and represents the main cause of morbidity and mortality in diabetes patients. Studies have indicated that major long-term complications of diabetes arise from persistent oxidative-nitrosative stress and dysregulation in multiple metabolic pathways. Presently, the main focus for diabetes management is to optimize the available techniques to ensure adequate blood sugar level, blood pressure and lipid profile, thereby minimizing the diabetes complications. In this regard, nanomedicine utilizing gold nanostructures has great potential and seems to be a promising option. The present review highlights the basic concepts and up-to-date literature survey of gold nanostructure materials in management of diabetes in several ways, which include sensing, imaging, drug delivery and therapy. The work can be of interest to various researchers working on basic and applied sciences including nanosciences.

  15. Nanostructured photovoltaic materials using block polymer assemblies

    NASA Astrophysics Data System (ADS)

    Mastroianni, Sarah Elizabeth

    Despite its potential as an abundant, sustainable alternative to non-renewable energy sources, solar energy currently is underutilized. Photovoltaics, which convert energy from sunlight into electricity, commonly are made from inorganic semiconductor materials that require expensive manufacturing and processing techniques. Alternatively, organic materials can be used to produce flexible and lightweight organic photovoltaic (OPV) devices, which can be prepared using solution-based processing techniques. However, OPV devices are limited by low efficiencies and short lifetimes compared to their inorganic counterparts. In OPV systems, charge carriers are generated in the active layer via the separation of excitons (electron-hole pairs) at interfaces between donor and acceptor materials. Because excitons have a limited diffusion length (˜10 nm), they may recombine before reaching a donor-acceptor interface if domain sizes are large. This exciton recombination can limit device efficiency; thus, the design parameters for improved active layer morphologies include large interfacial areas, small size scales, and continuous conducting pathways. Currently, most OPV devices are prepared by blending donor and acceptor materials in bulk heterojunction (BHJ) devices, often resulting in non-ideal, process-dependent morphologies. Alternatively, the self-assembly of block polymers (BP)s offers a reproducible means to generate nanostructured active layers. The work presented in this dissertation examines the synthetic approaches to preparing BPs containing different electroactive materials: non-conjugated, amorphous poly(vinyl-m-triphenylamine) [PVmTPA] and conjugated poly(3-alkythiophene) [P3AT] p-type materials as well as fullerene-based n-type materials. The synthesis and self-assembly of a model poly(methyl methacrylate)- b-PVmTPA system is presented. This work was extended to synthesize PVmTPA BPs with complementary poly(methyl methacrylate- co-hydroxyethyl methacrylate) [P

  16. Nanostructured Materials for Li-Ion Batteries and Beyond.

    PubMed

    Li, Xifei; Sun, Xueliang

    2016-04-07

    This Special Issue "Nanostructured Materials for Li-Ion Batteries and Beyond" of Nanomaterials is focused on advancements in the synthesis, optimization, and characterization of nanostructured materials, with an emphasis on the application of nanomaterials for building high performance Li-ion batteries (LIBs) and future systems.[...].

  17. Engineering Near-Field Transport of Energy using Nanostructured Materials

    DTIC Science & Technology

    2015-12-12

    applications. Recent computational studies on near-field radiative heat transfer (NFRHT) suggest that radiative energy transport between suitably chosen...Approved for Public Release; Distribution Unlimited Final Report: Engineering Near-Field Transport of Energy using Nanostructured Materials The views...Engineering Near-Field Transport of Energy using Nanostructured Materials Report Title The transport of heat at the nanometer scale is becoming

  18. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1984-01-01

    Progress is reported in studies of constituent materials composite materials, generic structural elements, processing science technology, and maintaining long-term structural integrity. Topics discussed include: mechanical properties of high performance carbon fibers; fatigue in composite materials; experimental and theoretical studies of moisture and temperature effects on the mechanical properties of graphite-epoxy laminates and neat resins; numerical investigations of the micromechanics of composite fracture; delamination failures of composite laminates; effect of notch size on composite laminates; improved beam theory for anisotropic materials; variation of resin properties through the thickness of cured samples; numerical analysis composite processing; heat treatment of metal matrix composites, and the RP-1 and RP2 gliders of the sailplane project.

  19. Thermal and Thermoelectric Properties of Nanostructured Materials and Interfaces

    NASA Astrophysics Data System (ADS)

    Liao, Hao-Hsiang

    Many modern technologies are enabled by the use of thin films and/or nanostructured composite materials. For example, many thermoelectric devices, solar cells, power electronics, thermal barrier coatings, and hard disk drives contain nanostructured materials where the thermal conductivity of the material is a critical parameter for the device performance. At the nanoscale, the mean free path and wavelength of heat carriers may become comparable to or smaller than the size of a nanostructured material and/or device. For nanostructured materials made from semiconductors and insulators, the additional phonon scattering mechanisms associated with the high density of interfaces and boundaries introduces additional resistances that can significantly change the thermal conductivity of the material as compared to a macroscale counterpart. Thus, better understanding and control of nanoscale heat conduction in solids is important scientifically and for the engineering applications mentioned above. In this dissertation, I discuss my work in two areas dealing with nanoscale thermal transport: (1) I describe my development and advancement of important thermal characterization tools for measurements of thermal and thermoelectric properties of a variety of materials from thin films to nanostructured bulk systems, and (2) I discuss my measurements on several materials systems done with these characterization tools. First, I describe the development, assembly, and modification of a time-domain thermoreflectance (TDTR) system that we use to measure the thermal conductivity and the interface thermal conductance of a variety of samples including nanocrystalline alloys of Ni-Fe and Co-P, bulk metallic glasses, and other thin films. Next, a unique thermoelectric measurement system was designed and assembled for measurements of electrical resistivity and thermopower of thermoelectric materials in the temperature range of 20 to 350 °C. Finally, a commercial Anter Flashline 3000 thermal

  20. Nanostructured Electrode Materials for Electrochemical Capacitor Applications

    PubMed Central

    Choi, Hojin; Yoon, Hyeonseok

    2015-01-01

    The advent of novel organic and inorganic nanomaterials in recent years, particularly nanostructured carbons, conducting polymers, and metal oxides, has enabled the fabrication of various energy devices with enhanced performance. In this paper, we review in detail different nanomaterials used in the fabrication of electrochemical capacitor electrodes and also give a brief overview of electric double-layer capacitors, pseudocapacitors, and hybrid capacitors. From a materials point of view, the latest trends in electrochemical capacitor research are also discussed through extensive analysis of the literature and by highlighting notable research examples (published mostly since 2013). Finally, a perspective on next-generation capacitor technology is also given, including the challenges that lie ahead. PMID:28347044

  1. Modeling plasticity of materials with nanostructure

    NASA Astrophysics Data System (ADS)

    Kudinova, N. R.

    2017-02-01

    A new approach to modeling of the plasticity of materials with the particle size in the range from 3 to 20 nm (nanostructure) has been proposed. It is based on classical thermodynamic approach employing the surface tension of nanoparticles. Its main advantage is the minimum number of physical parameters in use. In the context of the proposed model, we calculated the dependence of the melting temperature on the nanoparticle size which is consistent with experimental data. The volume density of the surface energy of nanoparticles was also determined. This energy is assumed to be a significant part of the internal energy during deformation Yield point was interpreted as the result of changes of grains surface energy during the deformation. The obtained yield point dependence on the grain size was related to the Hall–Petch law, and this resulted in confirmation of the hypothesis on the crucial role of surface tension forces in the initial stage of plastic deformation of nanomaterials.

  2. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Wiberley, S. E.

    1978-01-01

    The purpose of the RPI composites program is to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, reliability and life prediction. Concommitant goals are to educate engineers to design and use composite materials as normal or conventional materials. A multifaceted program was instituted to achieve these objectives.

  3. Cavitational synthesis of nanostructured inorganic materials for enhanced heterogeneous catalysis

    NASA Astrophysics Data System (ADS)

    Krausz, Ivo Michael

    The synthesis of nanostructured inorganic materials by hydrodynamic cavitation processing was investigated. The goal of this work was to develop a general synthesis technique for nanostructured materials with a control over crystallite size in the 1--20 nm range. Materials with crystallite sizes in this range have shown enhanced catalytic activity compared to materials with larger crystallite sizes. Several supported and unsupported inorganic materials were studied to understand the effects of cavitation on crystallite size. Cavitation processing of calcium fluoride resulted in more spherical particles, attached to one another by melted necks. This work produced the first evidence of shock wave heating of nanostructured materials by hydrodynamic cavitation processing. Hydrodynamic cavitation synthesis of various catalytic support materials indicated that their phase composition and purity could be controlled by adjustment of the processing parameters. Zirconia/alumina supports synthesized using hydro-dynamic cavitation and calcined to 1368 K retained a high purity cubic zirconia phase, whereas classically prepared samples showed a phase transformation to monoclinic zirconia. Similarly, the synthesis of alumina resulted in materials with varying Bohmite and Bayerite contents as a function of the process parameters. High temperature calcination resulted in stable alumina supports with varying amounts of delta-, and theta-alumina. Synthesis studies of palladium and silver showed modest variations in crystallite size as a function of cavitation process parameters. Calcination resulted in larger grain materials, indicating a disappearance of intergrain boundaries. Based on these results, a new synthesis method was studied involving controlled agglomeration of small silver crystallites by hydrodynamic cavitation processing, followed by deposition on alumina. The optimal pH, concentration, and processing time for controlling the silver crystallite size in the cavitation

  4. A Hybrid Laser/Aerosol Method for the Synthesis of Porous Nanostructured Calcium Phosphate Materials for Bone Tissue Engineering Applications

    DTIC Science & Technology

    2005-01-01

    carbon-based materials [4]. Nanostructured calcium phosphate bioceramics comprising mixtures of resorbable and nonresorbable calcium phosphate phases are...over the phase composition and microstructure of coatings of these mixtures, establishing them as suitable bioceramic substrates for bone tissue

  5. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R.; Wiberley, S. E.

    1986-01-01

    Overall emphasis is on basic long-term research in the following categories: constituent materials, composite materials, generic structural elements, processing science technology; and maintaining long-term structural integrity. Research in basic composition, characteristics, and processing science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to present and future problems. Detailed descriptions of the progress achieved in the various component parts of this comprehensive program are presented.

  6. Electrically conductive composite material

    DOEpatents

    Clough, R.L.; Sylwester, A.P.

    1988-06-20

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  7. Electrically conductive composite material

    SciTech Connect

    Clough, R.L.; Sylwester, A.P.

    1989-05-23

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  8. Composite Structural Materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

    1984-01-01

    The development and application of filamentary composite materials, is considered. Such interest is based on the possibility of using relatively brittle materials with high modulus, high strength, but low density in composites with good durability and high tolerance to damage. Fiber reinforced composite materials of this kind offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been made since the initial developments in the mid 1960's. There were only limited applied to the primary structure of operational vehicles, mainly as aircrafts.

  9. Electrically conductive composite material

    DOEpatents

    Clough, Roger L.; Sylwester, Alan P.

    1989-01-01

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistant pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like.

  10. Metallic glass nanostructures of tunable shape and composition.

    PubMed

    Liu, Yanhui; Liu, Jingbei; Sohn, Sungwoo; Li, Yanglin; Cha, Judy J; Schroers, Jan

    2015-04-22

    Metals of hybrid nano-/microstructures are of broad technological and fundamental interests. Manipulation of shape and composition on the nanoscale, however, is challenging, especially for multicomponent alloys such as metallic glasses. Although top-down approaches have demonstrated nanomoulding, they are limited to very few alloy systems. Here we report a facile method to synthesize metallic glass nanoarchitectures that can be applied to a broad range of glass-forming alloys. This strategy, using multitarget carousel oblique angle deposition, offers the opportunity to achieve control over size, shape and composition of complex alloys at the nanoscale. As a consequence, nanostructures of programmable three-dimensional shapes and tunable compositions are realized on wafer scale for metallic glasses including the marginal glass formers. Realizing nanostructures in a wide compositional range allows chemistry optimization for technological usage of metallic glass nanostructures, and also enables the fundamental study on size, composition and fabrication dependences of metallic glass properties.

  11. Exploring Deformation Mechanisms in Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Greer, Julia R.; Jang, Dongchan; Gu, X. Wendy

    2012-10-01

    effects of multiple grain boundaries spanning the sample volume (nanocrystalline and polycrystalline metals). This overview sheds light on the relative importance of intrinsic versus extrinsic length scale limitations on deformation mechanisms in nanostructured metals, which has significant implications for the development of new materials with tunable mechanical properties.

  12. Growth of Carbon Nanostructure Materials Using Laser Vaporization

    NASA Technical Reports Server (NTRS)

    Zhu, Shen; Su, Ching-Hua; Lehozeky, S.

    2000-01-01

    Since the potential applications of carbon nanotubes (CNT) was discovered in many fields, such as non-structure electronics, lightweight composite structure, and drug delivery, CNT has been grown by many techniques in which high yield single wall CNT has been produced by physical processes including arc vaporization and laser vaporization. In this presentation, the growth mechanism of the carbon nanostructure materials by laser vaporization is to be discussed. Carbon nanoparticles and nanotubes have been synthesized using pulsed laser vaporization on Si substrates in various temperatures and pressures. Two kinds of targets were used to grow the nanostructure materials. One was a pure graphite target and the other one contained Ni and Co catalysts. The growth temperatures were 600-1000 C and the pressures varied from several torr to 500 torr. Carbon nanoparticles were observed when a graphite target was used, although catalysts were deposited on substrates before growing carbon films. When the target contains catalysts, carbon nanotubes (CNT) are obtained. The CNT were characterized by scanning electron microscopy, x-ray diffraction, optical absorption and transmission, and Raman spectroscopy. The temperature-and pressure-dependencies of carbon nanotubes' growth rate and size were investigated.

  13. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1982-01-01

    The promise of filamentary composite materials, whose development may be considered as entering its second generation, continues to generate intense interest and applications activity. Fiber reinforced composite materials offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been achieved since the initial developments in the mid 1960's. Rather limited applications to primary aircraft structure have been made, however, mainly in a material-substitution mode on military aircraft, except for a few experiments currently underway on large passenger airplanes in commercial operation. To fulfill the promise of composite materials completely requires a strong technology base. NASA and AFOSR recognize the present state of the art to be such that to fully exploit composites in sophisticated aerospace structures, the technology base must be improved. This, in turn, calls for expanding fundamental knowledge and the means by which it can be successfully applied in design and manufacture.

  14. Composite Material Switches

    NASA Technical Reports Server (NTRS)

    Javadi, Hamid (Inventor)

    2001-01-01

    A device to protect electronic circuitry from high voltage transients is constructed from a relatively thin piece of conductive composite sandwiched between two conductors so that conduction is through the thickness of the composite piece. The device is based on the discovery that conduction through conductive composite materials in this configuration switches to a high resistance mode when exposed to voltages above a threshold voltage.

  15. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1982-01-01

    Research in the basic composition, characteristics, and processng science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to problems. Detailed descriptions of the progress achieved in the various component parts of his program are presented.

  16. High volume production of nanostructured materials

    DOEpatents

    Ripley, Edward B.; Morrell, Jonathan S.; Seals, Roland D.; Ludtka, Gerard M.

    2009-10-13

    A system and method for high volume production of nanoparticles, nanotubes, and items incorporating nanoparticles and nanotubes. Microwave, radio frequency, or infrared energy vaporizes a metal catalyst which, as it condenses, is contacted by carbon or other elements such as silicon, germanium, or boron to form agglomerates. The agglomerates may be annealed to accelerate the production of nanotubes. Magnetic or electric fields may be used to align the nanotubes during their production. The nanotubes may be separated from the production byproducts in aligned or non-aligned configurations. The agglomerates may be formed directly into tools, optionally in compositions that incorporate other materials such as abrasives, binders, carbon-carbon composites, and cermets.

  17. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1987-01-01

    The development and application of composite materials to aerospace vehicle structures which began in the mid 1960's has now progressed to the point where what can be considered entire airframes are being designed and built using composites. Issues related to the fabrication of non-resin matrix composites and the micro, mezzo and macromechanics of thermoplastic and metal matrix composites are emphasized. Several research efforts are presented. They are entitled: (1) The effects of chemical vapor deposition and thermal treatments on the properties of pitch-based carbon fiber; (2) Inelastic deformation of metal matrix laminates; (3) Analysis of fatigue damage in fibrous MMC laminates; (4) Delamination fracture toughness in thermoplastic matrix composites; (5) Numerical investigation of the microhardness of composite fracture; and (6) General beam theory for composite structures.

  18. Lyotropic liquid crystal directed synthesis of nanostructured materials

    PubMed Central

    Wang, Cuiqing; Chen, Dairong; Jiao, Xiuling

    2009-01-01

    This review introduces and summarizes lyotropic liquid crystal (LLC) directed syntheses of nanostructured materials consisting of porous nanostructures and zero-dimensional (0-D), one-dimensional (1-D) and two-dimensional (2-D) nanostructures. After a brief introduction to the liquid crystals, the LLCs used to prepare mesoporous materials are discussed; in particular, recent advances in controlling mesostructures are summarized. The LLC templates directing the syntheses of nanoparticles, nanorods, nanowires and nanoplates are also presented. Finally, future development in this field is discussed. PMID:27877273

  19. The influence of nanostructured materials on biointerfacial interactions.

    PubMed

    Koegler, Peter; Clayton, Andrew; Thissen, Helmut; Santos, Gil Nonato C; Kingshott, Peter

    2012-12-01

    Control over biointerfacial interactions in vitro and in vivo is the key to many biomedical applications: from cell culture and diagnostic tools to drug delivery, biomaterials and regenerative medicine. The increasing use of nanostructured materials is placing a greater demand on improving our understanding of how these new materials influence biointerfacial interactions, including protein adsorption and subsequent cellular responses. A range of nanoscale material properties influence these interactions, and material toxicity. The ability to manipulate both material nanochemistry and nanotopography remains challenging in its own right, however, a more in-depth knowledge of the subsequent biological responses to these new materials must occur simultaneously if they are ever to be affective in the clinic. We highlight some of the key technologies used for fabrication of nanostructured materials, examine how nanostructured materials influence the behavior of proteins and cells at surfaces and provide details of important analytical techniques used in this context.

  20. Polyaniline nanostructures expedient as working electrode materials in supercapacitors

    NASA Astrophysics Data System (ADS)

    Gedela, Venkata Ramana; Srikanth, Vadali Venkata Satya Siva

    2014-04-01

    Granular type polyaniline (PANi), PANi nanofibers (NFs), and PANi nanotubes (NTs) expedient as working electrode materials for supercapacitors are synthesized. The synthesis procedure used in this work facilitates not only the synthesis of solid powders of the PANi nanostructures, but also thin films constituted by the same PANi nanostructures in the same experiment. PANi NFs are found to exhibit faster electrode kinetics and better capacitance when compared to PANi NTs and granular PANi. Specific capacitance and energy storage per unit mass of PANi NFs are 239.47 Fg-1 (at 0.5 Ag-1) and 43.2 Wh kg-1, respectively. Electrical conductivity of PANi NFs is also better when compared to the other two nanostructures. Properties of the three PANi nanostructures are explicated in correlation with crystallinity, intrinsic oxidation state, doping degree, BET surface area, and ordered mesoporosity pertaining to the nanostructures.

  1. Development of Nanostructured Materials with Improved Radiation Tolerance for Advanced Nuclear Systems

    SciTech Connect

    Zinghang Zhang; K. Ted Hartwig

    2009-08-12

    This project will explore the fundamental mechanisms through which interfaces in nanolayered structures and grain boundaries of bulk nanomaterials are able to attract and rapidly eliminate point defects and unwanted foreign species. Candidate materials that will be studied include both nanostructured multilayer composites synthesized by magnetron sputtering and structural bulk nanomaterials produced by severed plastic deformation, equal channel angular extrusion.

  2. Surface analysis of nanostructured carbonaceous materials

    NASA Astrophysics Data System (ADS)

    Wepasnick, Kevin Andrew

    The characterization of surfaces is central to understanding its interaction with other materials. Current ground-breaking research in interfacial science is focusing on surfaces which have a nanoscopic-size to their structuring. In particular, carbon nanotubes (CNTs) have been explored extensively. However, to utilize these materials in commercial and scientific applications, the surfaces are often modified to tailor specific properties, such as dispersion, sorption, and reactivity. The focus of this thesis is to apply surface analytical techniques to explore the chemical and structural characteristics of modified nanostructured surfaces. Specifically studied are the covalent surface modifications of CNTs by strategies that involve the direct incorporation of specific elements into the graphene sidewalls by commonly used wet chemical oxidants. These resulting CNTs are then evaluated in terms of their change in surface chemistry and structure. X-ray photoelectron spectroscopy (XPS) was used to characterize the surface oxidation, while chemical derivatization techniques in conjunction with XPS afforded the concentration of carboxyl, carbonyl, and hydroxyl groups on the CNT surface. Transmission electron microscopy (TEM) was able to provide detailed structural information on the modified CNT, including the extent of sidewall damage. Results indicate that the distribution of oxygen-containing functional groups was insensitive to the reaction conditions, but was dependent upon the identity of the oxidant. These trends in functional group concentration were then applied to determining environmental properties, specifically divalent metal cation sorption. Consistently, the increases in COOH functional groups result in an increase in sorption capacity of divalent metal cations, such as Zn2+ and Cd2+. Furthermore, the interactions of size-selected metal and metal-oxide nanoclusters with graphite surfaces were studied by atomic force microscopy (AFM), scanning tunneling

  3. Modified Composite Materials Workshop

    NASA Technical Reports Server (NTRS)

    Dicus, D. L. (Compiler)

    1978-01-01

    The reduction or elimination of the hazard which results from accidental release of graphite fibers from composite materials was studied at a workshop. At the workshop, groups were organized to consider six topics: epoxy modifications, epoxy replacement, fiber modifications, fiber coatings and new fibers, hybrids, and fiber release testing. Because of the time required to develop a new material and acquire a design data base, most of the workers concluded that a modified composite material would require about four to five years of development and testing before it could be applied to aircraft structures. The hybrid working group considered that some hybrid composites which reduce the risk of accidental fiber release might be put into service over the near term. The fiber release testing working group recommended a coordinated effort to define a suitable laboratory test.

  4. Nano-structured polymer composites and process for preparing same

    DOEpatents

    Hillmyer, Marc; Chen, Liang

    2013-04-16

    A process for preparing a polymer composite that includes reacting (a) a multi-functional monomer and (b) a block copolymer comprising (i) a first block and (ii) a second block that includes a functional group capable of reacting with the multi-functional monomer, to form a crosslinked, nano-structured, bi-continuous composite. The composite includes a continuous matrix phase and a second continuous phase comprising the first block of the block copolymer.

  5. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1983-01-01

    Progress and plans are reported for investigations of: (1) the mechanical properties of high performance carbon fibers; (2) fatigue in composite materials; (3) moisture and temperature effects on the mechanical properties of graphite-epoxy laminates; (4) the theory of inhomogeneous swelling in epoxy resin; (5) numerical studies of the micromechanics of composite fracture; (6) free edge failures of composite laminates; (7) analysis of unbalanced laminates; (8) compact lug design; (9) quantification of Saint-Venant's principles for a general prismatic member; (10) variation of resin properties through the thickness of cured samples; and (11) the wing fuselage ensemble of the RP-1 and RP-2 sailplanes.

  6. Review on the application of nanostructure materials in solar cells

    NASA Astrophysics Data System (ADS)

    Afshar, Elham N.; Xosrovashvili, Georgi; Rouhi, Rasoul; Gorji, Nima E.

    2015-07-01

    In recent years, nanostructure materials have opened a promising route to future of the renewable sources, especially in the solar cells. This paper considers the advantages of nanostructure materials in improving the performance and stability of the solar cell structures. These structures have been employed for various performance/energy conversion enhancement strategies. Here, we have investigated four types of nanostructures applied in solar cells, where all of them are named as quantum solar cells. We have also discussed recent development of quantum dot nanoparticles and carbon nanotubes enabling quantum solar cells to be competitive with the conventional solar cells. Furthermore, the advantages, disadvantages and industrializing challenges of nanostructured solar cells have been investigated.

  7. Synthesis, characterization, and properties of low-dimensional nanostructured materials

    NASA Astrophysics Data System (ADS)

    Hu, Xianluo

    2007-05-01

    Nanometer scale structures represent an exciting and rapidly expanding area of research. Studies on new physical/chemical properties and applications of nanomaterials and nanostructures are possible only when nanostructured materials are made available with desired size, morphology, crystal and microstructure, and composition. Thus, controlled synthesis of nanomaterials is the essential aspect of nanotechnology. This thesis describes the development of simple and versatile solution-based approaches to synthesize low-dimensional nanostructures. The first major goal of this research is to design and fabricate morphology-controlled alpha-Fe 2O3 nanoarchitectures in aqueous solution through a programmed microwave-assisted hydrothermal route, taking advantage of microwave irradiation and hydrothermal effects. Free-standing alpha-Fe2O3 nanorings are prepared by hydrolysis of FeCl3 in the presence of phosphate ions. The as-formed architecture of alpha-Fe2O 3 nanorings is an exciting new member in the family of iron oxide nanostructures. Our preliminary results demonstrate that sensors made of the alpha-Fe 2O3 nanorings exhibit high sensitivity not only for bio-sensing of hydrogen peroxide in a physiological solution but also for gas-sensing of alcohol vapor at room temperature. Moreover, monodisperse alpha-Fe 2O3 nanocrystals with continuous aspect-ratio tuning and fine shape control are achieved by controlling the experimental conditions. The as-formed alpha-Fe2O3 exhibits shape-dependent infrared optical properties. The growth process of colloidal alpha-Fe 2O3 crystals in the presence of phosphate ions is discussed. In addition, through an efficient microwave-assisted hydrothermal process, self-assembled hierarchical alpha-Fe2O3 nanoarchitectures are synthesized on a large scale. The second major goal of this research is to develop convenient microwave-hydrothermal approaches for the fabrication of carbon-based nanocomposites: (1) A one-pot solution-phase route, namely

  8. ZnS nanostructure arrays: a developing material star.

    PubMed

    Fang, Xiaosheng; Wu, Limin; Hu, Linfeng

    2011-02-01

    Semiconductor nanostructure arrays are of great scientific and technical interest because of the strong non-linear and electro-optic effects that occur due to carrier confinement in three dimensions. The use of such nanostructure arrays with tailored geometry, array density, and length-diameter-ratio as building blocks are expected to play a crucial role in future nanoscale devices. With the unique properties of a direct wide-bandgap semiconductor, such as the presence of polar surfaces, excellent transport properties, good thermal stability, and high electronic mobility, ZnS nanostructure arrays has been a developing material star. The research on ZnS nanostructure arrays has seen remarkable progress over the last five years due to the unique properties and important potential applications of nanostructure arrays, which are summarized here. Firstly, a survey of various methods to the synthesis of ZnS nanostructure arrays will be introduced. Next recent efforts on exploiting the unique properties and applications of ZnS nanostructure arrays are discussed. Potential future directions of this research field are also highlighted.

  9. Nanoporous and Nanostructured Materials for Energy Storage and Sensor Applications

    NASA Astrophysics Data System (ADS)

    Vu, Anh D.

    The major objective of this work is to design nanostructured and nanoporous materials targeting the special needs of the energy storage and sensing fields. Nanostructured and nanoporous materials are increasingly finding applications in many fields, including electrical energy storage and explosive sensing. The advancement of energy storage devices is important to the development of three fields that have strong effects on human society: renewable energy, transportation, and portable devices. More sensitive explosive sensors will help to prevent terrorism activities and boost national security. Hierarchically porous LiFePO4 (LFP)/C composites were prepared using a surfactant and colloidal crystals as dual templates. The surfactant serves as the template for mesopores and polymeric colloidal spheres serve as the template for macropores. The confinement of the surfactant-LFP-carbon precursor in the colloidal templates is crucial to suppress the fast crystallization of LFP and helps to maintain the ordered structure. The obtained composites with high surface areas and ordered porous structure showed excellent rate performance when used as cathode materials for LIBs, which will allow them to be used as a power source for EVs and HEVs. The synthesis of LiFePO 4 in three dimensionally confined spaces within the colloidal template resulted in the formation of spherical particles. Densely packed LiFePO 4 spheres in a carbon matrix were obtained by spin-casting the LFP-carbon precursor on a quartz substrate and then pyrolyzing it. The product showed high capacity and could be charged /discharged with very little capacity fading over many cycles. Three-dimensionally ordered mesoporous carbons were prepared from nano-sized silica sphere colloidal crystal templates. These materials with very high surface areas and ordered porous structure showed high capacitance and excellent rate capability when used as electrodes for supercapacitors. Mesoporous silica thin films of different

  10. Advanced nanostructured materials for energy storage and conversion

    NASA Astrophysics Data System (ADS)

    Hutchings, Gregory S.

    Due to a global effort to reduce greenhouse gas emissions and to utilize renewable sources of energy, much effort has been directed towards creating new alternatives to fossil fuels. Identifying novel materials for energy storage and conversion can enable radical changes to the current fuel production infrastructure and energy utilization. The use of engineered nanostructured materials in these systems unlocks unique catalytic activity in practical configurations. In this work, research efforts have been focused on the development of nanostructured materials to address the need for both better energy conversion and storage, with applications toward Li-O2 battery electrocatalysts, electrocatalytic generation of H2, conversion of furfural to useful chemicals and fuels, and Li battery anode materials. Highly-active alpha-MnO2 materials were synthesized for use as bifunctional oxygen reduction (ORR) and evolution (OER) catalysts in Li-O2 batteries, and were evaluated under operating conditions with a novel in situ X-ray absorption spectroscopy configuration. Through detailed analysis of local coordination and oxidation states of Mn atoms at key points in the electrochemical cycle, a self-switching behavior affecting the bifunctional activity was identified and found to be critical. In an additional study of materials for lithium batteries, nanostructured TiO2 anode materials doped with first-row transition metals were synthesized and evaluated for improving battery discharge capacity and rate performance, with Ni and Co doping at low levels found to cause the greatest enhancement. In addition to battery technology research, I have also sought to find inexpensive and earth-abundant electrocatalysts to replace state-of-the-art Pt/C in the hydrogen evolution reaction (HER), a systematic computational study of Cu-based bimetallic electrocatalysts was performed. During the screening of dilute surface alloys of Cu mixed with other first-row transition metals, materials with

  11. Aerogel/polymer composite materials

    NASA Technical Reports Server (NTRS)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2010-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  12. Development of Methods for Surface Modification of Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Marsh, David A.

    The surfaces of a material become increasingly more influential when the dimensions are reduced, because a larger percentage of the atoms are exposed on the surface. The surface environment of nanostructured materials dictates both physical properties and function, but is synthetically challenging to control. Although the desired functionality is commonly introduced via post-synthetic modification, it would be advantageous to minimize the number of synthetic steps by having specific function installed in the precursor. This work describes efforts to investigate new precursor complexes for the synthesis of nanoparticles, in addition to electrochemical studies on single monolayer films for electrocatalysis. Chapter 2 focuses on the preparation of magnetic nanoaparticles, and the synthesis of a polymerizable surfactant, stacac, to be used to generate composite materials. Although an iron complex of stacac could be used as a precursor for magnetic nanoparticles, favorable composite materials could only be produced by introduction of stacac after isolation of magnetic nanoparticles. Chapter 3 describes the synthesis of Au(I) complexes with various thiourea-based ligands, to be used as precursors for gold nanoparticles. The experimental conditions were varied and parameters were found where addition of a reducing agent generated solution-stable gold nanoparticles in a reproducible manner. It was determined that only aggregated gold nanoparticles were produced when Au(I) complexes were generated in situ and the use of crystalline precursors resulted in soluble gold nanoparticles. Chapter 4 discusses the preparation of electrocatalysts for the oxidation of water with a focus on accurately determining the active surface area. A monolayer of cobalt was prepared on a gold electrode by underpotential deposition and used as an electrocatalyst for water oxidation. Because the surface area of gold can be measured directly, deposition of a single monolayer produced negligible

  13. Preparation of nanostructured materials having improved ductility

    DOEpatents

    Zhao, Yonghao; Zhu, Yuntian T.

    2010-04-20

    A method for preparing a nanostructured aluminum alloy involves heating an aluminum alloy workpiece at temperature sufficient to produce a single phase coarse grained aluminum alloy, then refining the grain size of the workpiece at a temperature at or below room temperature, and then aging the workpiece to precipitate second phase particles in the nanosized grains of the workpiece that increase the ductility without decreasing the strength of the workpiece.

  14. Modeling of space environment impact on nanostructured materials. General principles

    NASA Astrophysics Data System (ADS)

    Voronina, Ekaterina; Novikov, Lev

    2016-07-01

    In accordance with the resolution of ISO TC20/SC14 WG4/WG6 joint meeting, Technical Specification (TS) 'Modeling of space environment impact on nanostructured materials. General principles' which describes computer simulation methods of space environment impact on nanostructured materials is being prepared. Nanomaterials surpass traditional materials for space applications in many aspects due to their unique properties associated with nanoscale size of their constituents. This superiority in mechanical, thermal, electrical and optical properties will evidently inspire a wide range of applications in the next generation spacecraft intended for the long-term (~15-20 years) operation in near-Earth orbits and the automatic and manned interplanetary missions. Currently, ISO activity on developing standards concerning different issues of nanomaterials manufacturing and applications is high enough. Most such standards are related to production and characterization of nanostructures, however there is no ISO documents concerning nanomaterials behavior in different environmental conditions, including the space environment. The given TS deals with the peculiarities of the space environment impact on nanostructured materials (i.e. materials with structured objects which size in at least one dimension lies within 1-100 nm). The basic purpose of the document is the general description of the methodology of applying computer simulation methods which relate to different space and time scale to modeling processes occurring in nanostructured materials under the space environment impact. This document will emphasize the necessity of applying multiscale simulation approach and present the recommendations for the choice of the most appropriate methods (or a group of methods) for computer modeling of various processes that can occur in nanostructured materials under the influence of different space environment components. In addition, TS includes the description of possible

  15. Nanostructured Materials for Advanced Electrochemical Energy Storage Applications

    NASA Astrophysics Data System (ADS)

    Wilson, Benjamin E.

    This dissertation discusses work aimed at developing and improving nanostructured materials for electrochemical energy storage, specifically electrochemical double layer capacitors (EDLCs) and lithium-ion batteries (LIBs). This was achieved through a combination of templating, precursor selection, and heteroatom doping to control the morphology and composition of the materials for improved performance in both types of energy storage. The first part of the thesis discusses EDLCs. First, a new method to produce soft-templated carbon materials is described. This process allows for improved production of mesoporous carbon made through soft templating. The work continues with using ionic liquids to dope nitrogen into hard templated mesoporous carbon. This led to a 40% improvement in specific capacitance due to improved conductivity. The section concludes with an investigation of physical and electrochemical properties of twelve ionic liquid electrolytes to determine which parameters are most important to achieve a high energy density. The second part discusses my work on LIBs, starting with a design of a low-cost electrochemical cell for in-situ X-ray diffraction monitoring during galvanostatic cycling. It continues with the development of a novel cathode material, Li8ZrO6, with a high lithium content. In this material, the redox activity is localized on oxygen atoms. Li8ZrO6 displays initial capacities higher than those of commercial materials but has large polarization. The capacity is further improved with transition metal doping, leading to a final specific capacity of over 175 mAh/g after 140 cycles at a rate of C/5.

  16. European Composite Honeycomb Material

    NASA Astrophysics Data System (ADS)

    Tschepe, Christoph; Sauerbrey, Martin; Klebor, Maximillian; Henriksen, Torben

    2014-06-01

    A European CFRP honeycomb material for high demanding structure applications like antenna reflectors and optical benches was developed in the frame of an ESA GSTP project.The composite honeycomb was designed according to requirements defined by the European space industry. A developed manufacturing technique based on prepreg moulding enables the production of homogeneous CFRP honeycomb blocks. All characteristic material properties, including compression, tension and shear strength and CTE, were determined in a comprehensive verification test campaign. Competitiveness to comparable products was further verified by a representative breadboard.

  17. Preparation and properties on hollow nano-structured smoke material

    NASA Astrophysics Data System (ADS)

    Liu, Xiang-cui; Dai, Meng-yan; Fang, Guo-feng; Shi, Wei-dong; Cheng, Xiang; Liu, Hai-feng; Zhang, Tong

    2013-09-01

    In recent years, the weapon systems of laser guidance and infrared (IR) imaging guidance have been widely used in modern warfare because of their high precision and strong anti-interference. Notwithstanding, military smoke, as a rapid and effective passive jamming means, can effectively counteract the attack of enemy precision-guided weapons by scattering and absorbability. Conventional smoke has good attenuation capability only to visible light (0.4-0.76 μm), but hardly any effect to other electromagnetic wave band. The weapon systems of laser guidance and IR imaging guidance usually work in broad band, including near IR (1-3 μm), middle IR (3-5 μm), far IR (8-14 μm), and so on. Accordingly, exploiting and using new efficient obscurant materials, which is one of the important factors that develop smoke technology, have become a focus and attracted more interests around the world. Then nano-structured materials that are developing very quickly have turned into our new choice. Hollow nano-structured materials (HNSM) have many special properties because of their nano-size wall-thickness and sub-micron grain-size. After a lot of HNSM were synthesized in this paper, their physical and chemical properties, including grain size, phase composition, microstructure, optical properties and resistivity were tested and analysed. Then the experimental results of the optical properties showed that HNSM exhibit excellent wave-absorbing ability in ultraviolet, visible and infrared regions. On the basis of the physicochemmical properties, HNSM are firstly applied in smoke technology field. And the obscuration performance of HNSM smoke was tested in smoke chamber. The testing waveband included 1.06μm and 10.6μm laser, 3-5μm and 8-14μm IR radiation. Then the main parameters were obtained, including the attenuation rate, the transmission rate, the mass extinction coefficient, the efficiency obscuring time, and the sedimentation rate, etc. The main parameters of HNSM smoke were

  18. Advanced composite materials and processes

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.

    1991-01-01

    Composites are generally defined as two or more individual materials, which, when combined into a single material system, results in improved physical and/or mechanical properties. The freedom of choice of the starting components for composites allows the generation of materials that can be specifically tailored to meet a variety of applications. Advanced composites are described as a combination of high strength fibers and high performance polymer matrix materials. These advanced materials are required to permit future aircraft and spacecraft to perform in extended environments. Advanced composite precursor materials, processes for conversion of these materials to structures, and selected applications for composites are reviewed.

  19. Nanostructure materials for biosensing and bioimaging applications

    NASA Astrophysics Data System (ADS)

    Law, Wing Cheung

    not fully understand, three possible factors are concluded after systematic researches: (i) an increase of the absolute mass in each binding event, (ii) an increase in the bulk refractive index of the analyte, and (iii) coupling between the localized surface plasmon resonance (LSPR) of metallic nanoparticles and surface plasmon resonance (SPR) of the sensing film. Indeed, the role of plasmonic coupling in sensitivity enhancement is still an open question. In order to obtain a better understanding of this phenomenon, at the end of part I, extended studies were performed to investigate how the LSPR properties of metallic nanoparticle labels correlate with the enhancement factor. For this purpose, gold nanorods (Au-NRs) were chosen as the amplification labels because of the easy tunability of LSPR peak of Au-NR. After reading the "Result and Discussion" section, the readers will have better understanding of "plasmonic coupling" between the sensing film and the metallic labels with suitable operating laser source. In the second part of the thesis, the bioimaging part, the application of nanostructure materials in live cancer cell imaging and small animal imaging were demonstrated. There are different types of imaging technique available in laboratories and clinics: optical imaging, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), thermography and ultrasound imaging. Although such imaging techniques have been well developed and used over a decade, improving the sensitivity, enhancing the contrast, decreasing the acquisition time and reducing the toxicity of the contrast agent are highly desirable. For optical imaging, the scientists discovered that the use of near infrared fluorescence materials can assist the surgeon to locate the tumor, the nerve and the lymph node more accurately. For CT scan, the use of Au-NR as the contrast agent can improve the sensitivity. Iron oxide nanoparticle or gadolinium ion containing

  20. Scaling laws for van der Waals interactions in nanostructured materials.

    PubMed

    Gobre, Vivekanand V; Tkatchenko, Alexandre

    2013-01-01

    Van der Waals interactions have a fundamental role in biology, physics and chemistry, in particular in the self-assembly and the ensuing function of nanostructured materials. Here we utilize an efficient microscopic method to demonstrate that van der Waals interactions in nanomaterials act at distances greater than typically assumed, and can be characterized by different scaling laws depending on the dimensionality and size of the system. Specifically, we study the behaviour of van der Waals interactions in single-layer and multilayer graphene, fullerenes of varying size, single-wall carbon nanotubes and graphene nanoribbons. As a function of nanostructure size, the van der Waals coefficients follow unusual trends for all of the considered systems, and deviate significantly from the conventionally employed pairwise-additive picture. We propose that the peculiar van der Waals interactions in nanostructured materials could be exploited to control their self-assembly.

  1. Potential applications of nanostructured materials in nuclear waste management.

    SciTech Connect

    Braterman, Paul S. (The University of North Texas, Denton, TX); Phol, Phillip Isabio; Xu, Zhi-Ping (The University of North Texas, Denton, TX); Brinker, C. Jeffrey; Yang, Yi; Bryan, Charles R.; Yu, Kui; Xu, Huifang (University of New Mexico, Albuquerque, NM); Wang, Yifeng; Gao, Huizhen

    2003-09-01

    This report summarizes the results obtained from a Laboratory Directed Research & Development (LDRD) project entitled 'Investigation of Potential Applications of Self-Assembled Nanostructured Materials in Nuclear Waste Management'. The objectives of this project are to (1) provide a mechanistic understanding of the control of nanometer-scale structures on the ion sorption capability of materials and (2) develop appropriate engineering approaches to improving material properties based on such an understanding.

  2. Conducting nanotubes or nanostructures based composites, method of making them and applications

    NASA Technical Reports Server (NTRS)

    Gupta, Mool C. (Inventor); Yang, Yonglai (Inventor); Dudley, Kenneth L. (Inventor); Lawrence, Roland W. (Inventor)

    2013-01-01

    An electromagnetic interference (EMI) shielding material includes a matrix of a dielectric or partially conducting polymer, such as foamed polystyrene, with carbon nanotubes or other nanostructures dispersed therein in sufficient concentration to make the material electrically conducting. The composite is formed by dispersing the nanotube material in a solvent in which the dielectric or partially conducting polymer is soluble and mixing the resulting suspension with the dielectric or partially conducting polymer. A foaming agent can be added to produce a lightweight foamed material. An organometallic compound can be added to enhance the conductivity further by decomposition into a metal phase.

  3. Nanostructured Materials Developed for Solar Cells

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Castro, Stephanie L.; Raffaelle, Ryne P.; Fahey, Stephen D.; Gennett, Thomas; Tin, Padetha

    2004-01-01

    There has been considerable investigation recently regarding the potential for the use of nanomaterials and nanostructures to increase the efficiency of photovoltaic devices. Efforts at the NASA Glenn Research Center have involved the development and use of quantum dots and carbon nanotubes to enhance inorganic and organic cell efficiencies. Theoretical results have shown that a photovoltaic device with a single intermediate band of states resulting from the introduction of quantum dots offers a potential efficiency of 63.2 percent. A recent publication extended the intermediate band theory to two intermediate bands and calculated a limiting efficiency of 71.7 percent. The enhanced efficiency results from converting photons of energy less than the band gap of the cell by an intermediate band. The intermediate band provides a mechanism for low-energy photons to excite carriers across the energy gap by a two-step process.

  4. Briquettes with nanostructured materials used to modify of cast iron

    NASA Astrophysics Data System (ADS)

    Znamenskii, L. G.; Ivochkina, O. V.; Varlamov, A. S.; Petrova, N. I.

    2016-05-01

    A method is developed to fabricate briquettes with nanostructured materials aimed at modification of cast iron resulting in the improvement of the physicochemical properties of cast iron and its castings. This improvement is achieved by grain refinement, stable modification, the elimination of pyroelectric effect upon modification, and a decrease in the sensitivity to chilling upon melt solidification.

  5. Compositional ordering and stability in nanostructured, bulk thermoelectric alloys.

    SciTech Connect

    Hekmaty, Michelle A.; Faleev, S.; Medlin, Douglas L.; Leonard, F.; Lensch-Falk, J.; Sharma, Peter Anand; Sugar, J. D.

    2009-09-01

    Thermoelectric materials have many applications in the conversion of thermal energy to electrical power and in solid-state cooling. One route to improving thermoelectric energy conversion efficiency in bulk material is to embed nanoscale inclusions. This report summarize key results from a recently completed LDRD project exploring the science underpinning the formation and stability of nanostructures in bulk thermoelectric and the quantitative relationships between such structures and thermoelectric properties.

  6. Inelastic light scattering spectroscopy in Si/SiGe nanostructures: Strain, chemical composition and thermal properties

    NASA Astrophysics Data System (ADS)

    Tsybeskov, L.; Mala, S. A.; Wang, X.; Baribeau, J.-M.; Wu, X.; Lockwood, D. J.

    2016-11-01

    We present a review of recent studies of inelastic light scattering spectroscopy in two types of Si/SiGe nanostructures: planar superlattices and cluster (dot) multilayers including first- and second-order Raman scattering, polarized Raman scattering and low-frequency inelastic light scattering associated with folded acoustic phonons. The results are used in semi-quantitative analysis of chemical composition, strain and thermal conductivity in these technologically important materials for electronic and optoelectronic devices.

  7. Self-assembled peptide nanostructures for functional materials

    NASA Astrophysics Data System (ADS)

    Sardan Ekiz, Melis; Cinar, Goksu; Aref Khalily, Mohammad; Guler, Mustafa O.

    2016-10-01

    Nature is an important inspirational source for scientists, and presents complex and elegant examples of adaptive and intelligent systems created by self-assembly. Significant effort has been devoted to understanding these sophisticated systems. The self-assembly process enables us to create supramolecular nanostructures with high order and complexity, and peptide-based self-assembling building blocks can serve as suitable platforms to construct nanostructures showing diverse features and applications. In this review, peptide-based supramolecular assemblies will be discussed in terms of their synthesis, design, characterization and application. Peptide nanostructures are categorized based on their chemical and physical properties and will be examined by rationalizing the influence of peptide design on the resulting morphology and the methods employed to characterize these high order complex systems. Moreover, the application of self-assembled peptide nanomaterials as functional materials in information technologies and environmental sciences will be reviewed by providing examples from recently published high-impact studies.

  8. Spark Plasma Sintering for Nanostructured Smart Materials

    DTIC Science & Technology

    2009-03-02

    formulation originally proposed and now widely accepted Eshelby’s model. For paramagnetic materials (such as TiNi SMA material), the magnetic...consideration as depicted in Fig.2.5 (a). Essentially, Eq(2) conveys that due to the weak magnetization of paramagnetic materials constituting the...Equation (2.2) is valid for most paramagnetic materials such as TiNi for which the magnetization vector M » 0 . Equation (2.1) can thus be written as

  9. Nanostructured polymeric materials for hydrogen storage

    SciTech Connect

    Liu, Di-Jia

    2013-03-01

    The objective of this project is to develop a new class of hydrogen storage adsorbent, nanostructured porous organic polymers (POPs), through collaboration between Argonne National Laboratory and The University of Chicago. POPs have excellent thermal stability and tolerance to gas contaminants such as moisture. They also have low skeleton density and high intrinsic porosity via covalent bonds, capable of maintaining specific surface area (SSA) during high pressure pelletizing for better volumetric density. Furthermore, they can be produced at a commercial scale with the existing industrial infrastructure. The team’s approach focused on improving hydrogen uptake capacity and the heat of adsorption by enhancing SSA, porosity control, and framework-adsorbate interactions through rational design and synthesis at the molecular level. The design principles aim at improving the following attributes of the polymers: (a) high SSA to provide sufficient interface with H2; (b) narrow pore diameter to enhance van der Waals interactions in the confined space; and (c) “metallic” features, either through π- conjugation or metal doping, to promote electronic orbital interactions with hydrogen.

  10. Processing composite materials

    NASA Technical Reports Server (NTRS)

    Baucom, R. M.

    1982-01-01

    The fabrication of several composite structural articles including DC-10 upper aft rudders, L-1011 vertical fins and composite biomedical appliances are discussed. Innovative composite processing methods are included.

  11. Novel thermal properties of nanostructured materials.

    SciTech Connect

    Eastman, J. A.

    1999-01-13

    A new class of heat transfer fluids, termed nanofluids, has been developed by suspending nanocrystalline particles in liquids. Due to the orders-of-magnitude larger thermal conductivities of solids compared to those of liquids such as water, significantly enhanced thermal properties are obtained with nanofluids. For example, an approximately 20% improvement in effective thermal conductivity is observed when 5 vol.% CuO nanoparticles are added to water. Even more importantly, the heat transfer coefficient of water under dynamic flow conditions is increased more than 15% with the addition of less than 1 vol.% CuO particles. The use of nanofluids could impact many industrial sectors, including transportation, energy supply and production, electronics, textiles, and paper production by, for example, decreasing pumping power needs or reducing heat exchanger sizes. In contrast to the enhancement in effective thermal transport rates that is obtained when nanoparticles are suspended in fluids, nanocrystalline coatings are expected to exhibit reduced thermal conductivities compared to coarse-grained coatings. Reduced thermal conductivities are predicted to arise because of a reduction in the mean free path of phonons due to presence of grain boundaries. This behavior, combined with improved mechanical properties, makes nanostructured zirconia coatings excellent candidates for future applications as thermal barriers. Yttria-stabilized zirconia (YSZ) thin films are being produced by metal-organic chemical vapor deposition techniques. Preliminary results have indicated that the thermal conductivity is reduced by approximately a factor-of-two at room temperature in 10 nm grain-sized YSZ compared to coarse-grained or single crystal YSZ.

  12. Plasmon and compositional mapping of plasmonic nanostructures

    NASA Astrophysics Data System (ADS)

    Ringe, Emilie; Collins, Sean M.; DeSantis, Christopher J.; Skrabalak, Sara E.; Midgley, Paul A.

    2014-11-01

    Recently, co-reduction of Au and Pd has allowed the synthesis of complex Au core/AuPd shell nanoparticles with elongated tips and cubic-like symmetry. Optical studies have shown strong plasmonic behavior and high refractive index sensitivities. In this paper, we describe the composition and the near-field plasmonic behavior of those complex structures. Monochromated STEM-EELS, Cathodoluminescence, and EDS mapping reveals the different resonant modes in these particles, and shows that Pd, a poor plasmonic metal, does not prevent strong resonances and could actually be extremely helpful for plasmon-enhanced catalysis.

  13. Methods for fabrication of positional and compositionally controlled nanostructures on substrate

    DOEpatents

    Zhu, Ji; Grunes, Jeff; Choi, Yang-Kyu; Bokor, Jeffrey; Somorjai, Gabor

    2013-07-16

    Fabrication methods disclosed herein provide for a nanoscale structure or a pattern comprising a plurality of nanostructures of specific predetermined position, shape and composition, including nanostructure arrays having large area at high throughput necessary for industrial production. The resultant nanostracture patterns are useful for nanostructure arrays, specifically sensor and catalytic arrays.

  14. Nanostructured Block Copolymer Solutions and Composites: Mechanical and Structural Properties

    NASA Astrophysics Data System (ADS)

    Walker, Lynn

    2015-03-01

    Self-assembled block copolymer templates are used to control the nanoscale structure of materials that would not otherwise order in solution. In this work, we have developed a technique to use close-packed cubic and cylindrical mesophases of a thermoreversible block copolymer (PEO-PPO-PEO) to impart spatial order on dispersed nanoparticles. The thermoreversible nature of the template allows for the dispersion of particles synthesized outside the template. This feature extends the applicability of this templating method to many particle-polymer systems, including proteins, and also permits a systematic evaluation of the impact of design parameters on the structure and mechanical properties of the nanocomposites. The criteria for forming co-crystals have been characterized using small-angle scatting and the mechanical properties of these soft crystals determined. Numerous crystal structures have been reported for the block copolymer system and we have taken advantage of several to generate soft co-crystals. The result of this templating is spatially ordered nanoparticle arrays embedded within the block copolymer nanostructure. These soft materials can be shear aligned into crystals with long range order and this shear alignment is discussed. Finally, the dynamics of nanoparticles within the nanostructured material are characterized with fluorescence recovery after photobleaching (FRAP). The applications and general behavior of these nanostructured hydrogels are outlined.

  15. Bioapplicable, nanostructured and nanocomposite materials for catalytic and biosensor applications

    NASA Astrophysics Data System (ADS)

    Patel, Alpa C.

    Novel, nanostructured porous nanocomposites and bioapplicable materials have been successfully developed for catalytic, sensor and reinforcement applications. For the first time, porous silver nanoparticle/silica composites were synthesized using a simple method of silver nitrate reduction. The glucose template present inside the mesoporous silica material reduces silver nitrate to silver nanoparticles. The particles thus formed are lodged inside the porous silica matrix. Organic/inorganic hybrid nanofiber mats were fabricated for the first time using the electrospinning technology. The fiber mats have high surface area and good mechanical properties. These fibers mats are then used in reinforcement applications, by utilizing them as fillers in dental materials. The mechanical properties of dental materials thus produced are seen to improve dramatically with the addition of just a small amount of fiber sample. An in-situ method was used to produce silver and gold nanoparticles inside porous silica nanofibers via electrospinning. Metal salts used to produce the nanoparticles are mixed with silica and polymer precursors and spun into fibers. The fibers are then heat-treated to reduce the metal salt into metal nanoparticles. The factors affecting the size and distribution of the nanoparticles inside the porous fibers were studied. The fibers thus produced were then tested for catalytic activity. Horseradish peroxidase (HRP) enzyme was also encapsulated in porous silica nanofibers via electrospinning. The fibers showed significant enhancement in enzyme activity, which was three orders of magnitude greater than that of the non-templated, conventional microporous silica materials. The factors affecting the enzyme activity, like pH, temperature, etc., was also studied. The response time of the encapsulated enzymes to the external reagents was ˜ 2 to 3 seconds, showing high efficiency of the fibers to sensor applications. Finally, the encapsulation and alignment of

  16. Applications of ultrasound to the synthesis of nanostructured materials.

    PubMed

    Bang, Jin Ho; Suslick, Kenneth S

    2010-03-12

    Recent advances in nanostructured materials have been led by the development of new synthetic methods that provide control over size, morphology, and nano/microstructure. The utilization of high intensity ultrasound offers a facile, versatile synthetic tool for nanostructured materials that are often unavailable by conventional methods. The primary physical phenomena associated with ultrasound that are relevant to materials synthesis are cavitation and nebulization. Acoustic cavitation (the formation, growth, and implosive collapse of bubbles in a liquid) creates extreme conditions inside the collapsing bubble and serves as the origin of most sonochemical phenomena in liquids or liquid-solid slurries. Nebulization (the creation of mist from ultrasound passing through a liquid and impinging on a liquid-gas interface) is the basis for ultrasonic spray pyrolysis (USP) with subsequent reactions occurring in the heated droplets of the mist. In both cases, we have examples of phase-separated attoliter microreactors: for sonochemistry, it is a hot gas inside bubbles isolated from one another in a liquid, while for USP it is hot droplets isolated from one another in a gas. Cavitation-induced sonochemistry provides a unique interaction between energy and matter, with hot spots inside the bubbles of approximately 5000 K, pressures of approximately 1000 bar, heating and cooling rates of >10(10) K s(-1); these extraordinary conditions permit access to a range of chemical reaction space normally not accessible, which allows for the synthesis of a wide variety of unusual nanostructured materials. Complementary to cavitational chemistry, the microdroplet reactors created by USP facilitate the formation of a wide range of nanocomposites. In this review, we summarize the fundamental principles of both synthetic methods and recent development in the applications of ultrasound in nanostructured materials synthesis.

  17. Combination of lightweight elements and nanostructured materials for batteries.

    PubMed

    Chen, Jun; Cheng, Fangyi

    2009-06-16

    In a society that increasingly relies on mobile electronics, demand is rapidly growing for both primary and rechargeable batteries that power devices from cell phones to vehicles. Existing batteries utilize lightweight active materials that use electrochemical reactions of ions such as H(+), OH(-) and Li(+)/Mg(2+) to facilitate energy storage and conversion. Ideal batteries should be inexpensive, have high energy density, and be made from environmentally friendly materials; batteries based on bulk active materials do not meet these requirements. Because of slow electrode process kinetics and low-rate ionic diffusion/migration, most conventional batteries demonstrate huge gaps between their theoretical and practical performance. Therefore, efforts are underway to improve existing battery technologies and develop new electrode reactions for the next generation of electrochemical devices. Advances in electrochemistry, surface science, and materials chemistry are leading to the use of nanomaterials for efficient energy storage and conversion. Nanostructures offer advantages over comparable bulk materials in improving battery performance. This Account summarizes our progress in battery development using a combination of lightweight elements and nanostructured materials. We highlight the benefits of nanostructured active materials for primary zinc-manganese dioxide (Zn-Mn), lithium-manganese dioxide (Li-Mn), and metal (Mg, Al, Zn)-air batteries, as well as rechargeable lithium ion (Li-ion) and nickel-metal hydride (Ni-MH) batteries. Through selected examples, we illustrate the effect of structure, shape, and size on the electrochemical properties of electrode materials. Because of their numerous active sites and facile electronic/ionic transfer and diffusion, nanostructures can improve battery efficiency. In particular, we demonstrate the properties of nanostructured active materials including Mg, Al, Si, Zn, MnO(2), CuV(2)O(6), LiNi(0.8)Co(0.2)O(2), LiFePO(4), Fe(2)O(3

  18. Probing Compositional Variation within Hybrid Nanostructures

    SciTech Connect

    Yuhas, Benjamin D.; Habas, Susan E.; Fakra, Sirine C.; Mokari, Taleb

    2010-06-22

    We present a detailed analysis of the structural and magnetic properties of solution-grown PtCo-CdS hybrid structures in comparison to similar free-standing PtCo alloy nanoparticles. X-ray absorption spectroscopy is utilized as a sensitive probe for identifying subtle differences in the structure of the hybrid materials. We found that the growth of bimetallic tips on a CdS nanorod substrate leads to a more complex nanoparticle structure composed of a PtCo alloy core and thin CoO shell. The core-shell architecture is an unexpected consequence of the different nanoparticle growth mechanism on the nanorod tip, as compared to free growth in solution. Magnetic measurements indicate that the PtCo-CdS hybrid structures are superparamagnetic despite the presence of a CoO shell. The use of X-ray spectroscopic techniques to detect minute differences in atomic structure and bonding in complex nanosystems makes it possible to better understand and predict catalytic or magnetic properties for nanoscale bimetallic hybrid materials.

  19. Biocompatibility and nanostructured materials: applications in nanomedicine.

    PubMed

    Adabi, Mahdi; Naghibzadeh, Majid; Adabi, Mohsen; Zarrinfard, Mohammad Ali; Esnaashari, Seyedeh Sara; Seifalian, Alexander M; Faridi-Majidi, Reza; Tanimowo Aiyelabegan, Hammed; Ghanbari, Hossein

    2017-06-01

    There has been huge interest in applications of nanomaterials in biomedical science, including diagnosis, drug delivery, and development of human organs. Number of these nanomaterials has been already studied in human or at pre-clinical trial. There is a growing concern on potential toxicity and adverse effects of nanomaterials on human health, including lack of standard method of assessment of toxicology of these materials. Our investigation indicated that the bare and small nanoparticle have higher toxicity than modified and bulk materials, respectively. In addition, spherical nanoparticles have less toxicity than rod nanoparticles due to immune response of body.

  20. Composite material and method for production of improved composite material

    NASA Technical Reports Server (NTRS)

    Farley, Gary L. (Inventor)

    1996-01-01

    A laminated composite material with improved interlaminar strength and damage tolerance having short rods distributed evenly throughout the composite material perpendicular to the laminae. Each rod is shorter than the thickness of the finished laminate, but several times as long as the thickness of each lamina. The laminate is made by inserting short rods in layers of prepreg material, and then stacking and curing prepreg material with rods inserted therethrough.

  1. Laser Propagation in Nanostructured Ultra-Low-Density Materials

    SciTech Connect

    Fournier, K. B.; Colvin, J.; Yogo, A; Kemp, G. E.; Matsukuma, H.; Tanaka, N.; Zhang, Z.; Koga, K.; Tosaki, S.; Nishimura, H.

    2016-03-15

    The nanostructure of very-low-density aerogels (< 10 mg/cm3) affects the laser heating and propagation of the subsequent heat front. Simulations treat these materials as an atomistic medium without any structure differentiating between near-solid-density material and voids. Thus, simulations fail to predict the effects of the aerogel’s physical micro or nanostructure on the laser-matter interaction. We have designed an experiment using the GEKKO XII laser and ILE diagnostics to characterize the ionization-wave propagation and x-ray yield from aerogel and mass-matched gaseous targets as the laser passes through each. By design, the gas and aerogel targets will have identical densities and identical effective ionization states.

  2. Equivalent-Continuum Modeling of Nano-Structured Materials

    NASA Technical Reports Server (NTRS)

    Odegard, Gregory M.; Gates, Thomas S.; Nicholson, Lee M.; Wise, Kristopher E.

    2001-01-01

    A method has been developed for modeling structure-property relationships of nano-structured materials. This method serves as a link between computational chemistry and solid mechanics by substituting discrete molecular structures with an equivalent-continuum model. It has been shown that this substitution may be accomplished by equating the vibrational potential energy of a nano-structured material with the strain energy of representative truss and continuum models. As an important example with direct application to the development and characterization of single-walled carbon nanotubes, the model has been applied to determine the effective continuum geometry of a graphene sheet. A representative volume element of the equivalent-continuum model has been developed with an effective thickness. This effective thickness has been shown to be similar to, but slightly smaller than, the interatomic spacing of graphite.

  3. Nanostructured core-shell electrode materials for electrochemical capacitors

    NASA Astrophysics Data System (ADS)

    Jiang, Long-bo; Yuan, Xing-zhong; Liang, Jie; Zhang, Jin; Wang, Hou; Zeng, Guang-ming

    2016-11-01

    Core-shell nanostructure represents a unique system for applications in electrochemical energy storage devices. Owing to the unique characteristics featuring high power delivery and long-term cycling stability, electrochemical capacitors (ECs) have emerged as one of the most attractive electrochemical storage systems since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review aims to summarize recent progress on core-shell nanostructures for advanced supercapacitor applications in view of their hierarchical architecture which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The core-shell nanostructures include carbon/carbon, carbon/metal oxide, carbon/conducting polymer, metal oxide/metal oxide, metal oxide/conducting polymer, conducting polymer/conducting polymer, and even more complex ternary core-shell nanoparticles. The preparation strategies, electrochemical performances, and structural stabilities of core-shell materials for ECs are summarized. The relationship between core-shell nanostructure and electrochemical performance is discussed in detail. In addition, the challenges and new trends in core-shell nanomaterials development have also been proposed.

  4. Nanostructured Assemblies of Thermoelectric Composite Materials

    SciTech Connect

    Peter K. Dorhout; Ellen R. Fisher

    2008-02-26

    At the end of the funding period (March 2003) for our program in ferroelectric oxide nanomaterials, we had 3 publications in print, one more had been submitted and two more were in preparation in peer-reviewed journals and invited symposia lectures had been given since starting the project in the Fall of 1999. We hired two postdoctoral fellows, Dr. Ki-Seog Chang and Dr. Wenzhong Wang. We have also trained two graduate students, Ms. Keri Williams and Ms. Bernadette Hernandez, and one undergraduate student (Mr. Michael Scancella).

  5. 2D Hybrid Nanostructured Dirac Materials for Broadband Transparent Electrodes.

    PubMed

    Guo, Yunfan; Lin, Li; Zhao, Shuli; Deng, Bing; Chen, Hongliang; Ma, Bangjun; Wu, Jinxiong; Yin, Jianbo; Liu, Zhongfan; Peng, Hailin

    2015-08-05

    Broadband transparent electrodes based on 2D hybrid nanostructured Dirac materials between Bi2 Se3 and graphene are synthesized using a chemical vapor deposition (CVD) method. Bi2 Se3 nanoplates are preferentially grown along graphene grain boundaries as "smart" conductive patches to bridge the graphene boundary. These hybrid films increase by one- to threefold in conductivity while remaining highly transparent over broadband wavelength. They also display outstanding chemical stability and mechanical flexibility.

  6. Optical properties of nanostructured materials: a review

    NASA Astrophysics Data System (ADS)

    Flory, François; Escoubas, Ludovic; Berginc, Gérard

    2011-01-01

    Depending on the size of the smallest feature, the interaction of light with structured materials can be very different. This fundamental problem is treated by different theories. If first order theories are sufficient to describe the scattering from low roughness surfaces, second order or even higher order theories must be used for high roughness surfaces. Random surface structures can then be designed to distribute the light in different propagation directions. For complex structures such as black silicon, which reflects very little light, the theory needs further development. When the material is periodically structured, we speak about photonic crystals or metamaterials. Different theoretical approaches have been developed and experimental techniques are rapidly progressing. However, some work still remains to understand the full potential of this field. When the material is structured in dimension much smaller than the wavelength, the notion of complex refractive index must be revisited. Plasmon resonance can be excited by a progressing wave on metallic nanoparticles inducing a shaping of the absorption band and of the dispersion of the extinction coefficient. This addresses the problem of the permittivity of such metallic nanoparticles. The coupling between several metallic nanoparticles induces a field enhancement in the surrounding media, which can increase phenomena like scattering, absorption, luminescence, or Raman scattering. For semiconductor nanoparticles, electron confinement also induces a modulated absorption spectra. The refractive index is then modified. The bandgap of the material is changed because of the discretization of the electron energy, which can be controlled by the nanometers size particles. Such quantum dots behave like atoms and become luminescent. The lifetime of the electron in the excited states are much larger than in continuous energy bands. Electrons in coupled quantum dots behave as they do in molecules. Many applications

  7. Supersonic Nanocrystal Deposition for Nanostructured Materials

    DTIC Science & Technology

    2001-11-01

    element. Previous work has characterized the nanoerystals produced by ablation of silver microparticles. In addition to silver and cadmium selenide , several...silver and cadmium selenide in argon the kinetic energy per atom is limited to 0.03 eV/atom while for helium it is up to 0.3 cV/atom. Therefore materials...2. Cadmium Selenide nanocrystals deposited at low kinetic energy in argon carrier gas. The main TEM micrograph shows the overall size distribution and

  8. Tailoring properties and functionalities of nanostructures through compositions, components and morphologies

    NASA Astrophysics Data System (ADS)

    Weng, Lin

    The field of nanoscience and nanotechnology has made significant progresses over the last thirty years. Sophisticated nanostructures with tunable properties for novel physics and applications have been successfully fabricated, characterized and underwent practical test. In this thesis, I will focus on our recent efforts to develop new strategies to manipulate the properties of nanostructures. Particularly, three questions have been answered from our perspective, based on the nanomaterials synthesized: (1) How does the composition affect a novel nanostructure? We started from single-molecule precursors to reach nanostructures whose bulk counterparts only exist under extreme conditions. Fe3S and Fe3S2 are used as examples to demonstrate this synthetic strategy. Their potential magnetic properties have been measured, which may lead to interesting findings in astronomy and materials science. (2) How to achieve modularity control at nanoscale by a general bottom-up approach? Starting with reviewing the current status of this field, our recent experimental progresses towards delicate modularity control are presented by abundant novel heteronanostructures. An interesting catalytic mechanism of these nanostructures has also been verified, which involves the interaction between phonons, photons, plasmons, and excitons. (3) What can the morphology difference tell us about the inside of nanostructures? By comparing a series of data from three types of CdSe/CdS core-shell structures, a conclusion has been reached on the CdS growth mechanism on CdSe under different conditions, which also may lead to a solution to the asymmetry problem in the synthesis of CdSe/CdS nanorods. Finally this thesis is concluded by a summary and future outlook.

  9. In situ neutron scattering study of nanostructured PbTe-PbS bulk thermoelectric material

    SciTech Connect

    Ren, Fei; Schmidt, Robert D; Case, Eldon D; An, Ke

    2016-01-01

    Nanostructures play an important role in thermoelectric materials. Their thermal stability, such as phase change and evolution at elevated temperatures, is thus of great interest to the thermoelectric community. In this study, in situ neutron diffraction was used to examine the phase evolution of nanostructured bulk PbTe-PbS materials fabricated using hot pressing and pulsed electrical current sintering (PECS). The PbS second phase was observed in all samples in the as-pressed condition. The temperature dependent lattice parameter and phase composition data show an initial formation of PbS precipitates followed by a redissolution during heating. The redissolution process started around 570 600 K, and completed at approximately 780 K. During cooling, the PECS sample followed a reversible curve while the heating/cooling behavior of the hot pressed sample was irreversible.

  10. Erosion-resistant composite material

    DOEpatents

    Finch, C.B.; Tennery, V.J.; Curlee, R.M.

    A highly erosion-resistant composite material is formed of chemical vapor-deposited titanium diboride on a sintered titanium diboride-nickel substrate. This material may be suitable for use in cutting tools, coal liquefaction systems, etc.

  11. Fabrication and characterization of nanostructured III-V thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Novotny, Clint; Sharifi, Fred

    2013-09-01

    Approximately two thirds of all fossil fuel used is lost as heat. Thermoelectric materials, which convert heat into electrical energy, may provide a solution to partially recover some of this lost energy. To date, most commercial thermoelectric materials are too inefficient to be a viable option for most waste heat applications. This research proposes to investigate the fabrication and characterization of nanostructured III-V semiconductor thermoelectric materials with the goal of increasing the performance of existing technology. In order to improve thermoelectric material efficiency, either the lattice thermal conductivity must be lowered or the thermoelectric power factor must be increased. This research will focus on the latter by modifying the density of states of the semiconductor material and studying the effect of quantum confinement on the material's thermoelectric properties. Using focused ion beam milling, nanostructured cantilevers are fabricated from single crystal wafers. An all around gate dielectric and electrode are deposited to create a depletion region along the outer core of the cantilever, thus creating an inner conductive core. The Seebeck coefficient can then be measured as a function of confinement by varying the gate voltage. This technique can be applied to various material systems to investigate the effects of confinement on their thermoelectric properties.

  12. Nanostructured Mo-based electrode materials for electrochemical energy storage.

    PubMed

    Hu, Xianluo; Zhang, Wei; Liu, Xiaoxiao; Mei, Yueni; Huang, Yunhui

    2015-04-21

    The development of advanced energy storage devices is at the forefront of research geared towards a sustainable future. Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport features, and attractive physicochemical properties. They have been extensively explored in various fields of energy storage and conversion. This review is focused largely on the recent progress in nanostructured Mo-based electrode materials including molybdenum oxides (MoO(x), 2 ≤ x ≤ 3), dichalconides (MoX2, X = S, Se), and oxysalts for rechargeable lithium/sodium-ion batteries, Mg batteries, and supercapacitors. Mo-based compounds including MoO2, MoO3, MoO(3-y) (0 < y < 1), MMo(x)O(y) (M = Fe, Co, Ni, Ca, Mn, Zn, Mg, or Cd; x = 1, y = 4; x = 3, y = 8), MoS2, MoSe2, (MoO2)2P2O7, LiMoO2, Li2MoO3, etc. possess multiple valence states and exhibit rich chemistry. They are very attractive candidates for efficient electrochemical energy storage systems because of their unique physicochemical properties, such as conductivity, mechanical and thermal stability, and cyclability. In this review, we aim to provide a systematic summary of the synthesis, modification, and electrochemical performance of nanostructured Mo-based compounds, as well as their energy storage applications in lithium/sodium-ion batteries, Mg batteries, and pseudocapacitors. The relationship between nanoarchitectures and electrochemical performances as well as the related charge-storage mechanism is discussed. Moreover, remarks on the challenges and perspectives of Mo-containing compounds for further development in electrochemical energy storage applications are proposed. This review sheds light on the sustainable development of advanced rechargeable batteries and supercapacitors with nanostructured Mo-based electrode materials.

  13. Ceramic materials and nanostructures for chemical sensing

    NASA Astrophysics Data System (ADS)

    Azad, Abdul-Majeed; Akbar, Sheikh A.

    2005-11-01

    High selectivity, enhanced sensitivity, short response time and long shelf-life are some of the key features sought in the solid-state ceramic-based chemical sensors. Since the sensing mechanism and catalytic activity are predominantly surface-dominated, benign surface features in terms of higher aspect ratio, large surface area and, open and connected porosity, are required to realize a successful material. In order to incorporate these morphological features, a technique based on rigorous thermodynamic consideration of the metal/metal oxide coexistence, is described. By modulating the oxygen partial pressure across the equilibrium M/MO proximity line, formation and growth of new oxide surface on an atomic/ submolecular level under conditions of "oxygen deprivation", with exotic morphological features has been achieved in a number of metal oxides that are potential sensor materials. This paper describes the methodology and discusses the results obtained in the case of two model systems, viz., tungsten oxide (WO3) and titanium oxide (TiO2).

  14. Characterization of gas tunnel type plasma sprayed hydroxyapatite-nanostructure titania composite coatings

    NASA Astrophysics Data System (ADS)

    Yugeswaran, S.; Kobayashi, A.; Ucisik, A. Hikmet; Subramanian, B.

    2015-08-01

    Hydroxyapatite (HA) can be coated onto metal implants as a ceramic biocompatible coating to bridge the growth between implants and human tissue. Meanwhile many efforts have been made to improve the mechanical properties of the HA coatings without affecting its bioactivity. In the present study, nanostructure titania (TiO2) was mixed with HA powder and HA-nanostructure TiO2 composite coatings were produced by gas tunnel type plasma spraying torch under optimized spraying conditions. For this purpose, composition of 10 wt% TiO2 + 90 wt% HA, 20 wt% TiO2 + 80 wt% HA and 30 wt% TiO2 + 70 wt% HA were selected as the feedstock materials. The phase, microstructure and mechanical properties of the coatings were characterized. The obtained results validated that the increase in weight percentage of nanostructure TiO2 in HA coating significantly increased the microhardness, adhesive strength and wear resistance of the coatings. Analysis of the in vitro bioactivity and cytocompatibility of the coatings were done using conventional simulated body fluid (c-SBF) solution and cultured green fluorescent protein (GFP) labeled marrow stromal cells (MSCs) respectively. The bioactivity results revealed that the composite coating has bio-active surface with good cytocompatibility.

  15. Nanostructured electrocatalyst for fuel cells : silica templated synthesis of Pt/C composites.

    SciTech Connect

    Stechel, Ellen Beth; Switzer, Elise E.; Fujimoto, Cy H.; Atanassov, Plamen Borissov; Cornelius, Christopher James; Hibbs, Michael R.

    2007-09-01

    Platinum-based electrocatalysts are currently required for state-of-the-art fuel cells and represent a significant portion of the overall fuel cell cost. If fuel cell technology is to become competitive with other energy conversion technologies, improve the utilization of precious metal catalysts is essential. A primary focus of this work is on creating enhanced nanostructured materials which improve precious-metal utilization. The goal is to engineer superior electrocatalytic materials through the synthesis, development and investigation of novel templated open frame structures synthesized in an aerosol-based approach. Bulk templating methods for both Pt/C and Pt-Ru composites are evaluated in this study and are found to be limited due to the fact that the nanostructure is not maintained throughout the entire sample. Therefore, an accurate examination of structural effects was previously impossible. An aerosol-based templating method of synthesizing nanostructured Pt-Ru electrocatalysts has been developed wherein the effects of structure can be related to electrocatalytic performance. The aerosol-based templating method developed in this work is extremely versatile as it can be conveniently modified to synthesize alternative materials for other systems. The synthesis method was able to be extended to nanostructured Pt-Sn for ethanol oxidation in alkaline media. Nanostructured Pt-Sn electrocatalysts were evaluated in a unique approach tailored to electrocatalytic studies in alkaline media. At low temperatures, nanostructured Pt-Sn electrocatalysts were found to have significantly higher ethanol oxidation activity than a comparable nanostructured Pt catalyst. At higher temperatures, the oxygen-containing species contribution likely provided by Sn is insignificant due to a more oxidized Pt surface. The importance of the surface coverage of oxygen-containing species in the reaction mechanism is established in these studies. The investigations in this work present

  16. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1981-01-01

    The composite aircraft program component (CAPCOMP) is a graduate level project conducted in parallel with a composite structures program. The composite aircraft program glider (CAPGLIDE) is an undergraduate demonstration project which has as its objectives the design, fabrication, and testing of a foot launched ultralight glider using composite structures. The objective of the computer aided design (COMPAD) portion of the composites project is to provide computer tools for the analysis and design of composite structures. The major thrust of COMPAD is in the finite element area with effort directed at implementing finite element analysis capabilities and developing interactive graphics preprocessing and postprocessing capabilities. The criteria for selecting research projects to be conducted under the innovative and supporting research (INSURE) program are described.

  17. Nanostructured materials for applications in drug delivery and tissue engineering*

    PubMed Central

    GOLDBERG, MICHAEL; LANGER, ROBERT; JIA, XINQIAO

    2010-01-01

    Research in the areas of drug delivery and tissue engineering has witnessed tremendous progress in recent years due to their unlimited potential to improve human health. Meanwhile, the development of nanotechnology provides opportunities to characterize, manipulate and organize matter systematically at the nanometer scale. Biomaterials with nano-scale organizations have been used as controlled release reservoirs for drug delivery and artificial matrices for tissue engineering. Drug-delivery systems can be synthesized with controlled composition, shape, size and morphology. Their surface properties can be manipulated to increase solubility, immunocompatibility and cellular uptake. The limitations of current drug delivery systems include suboptimal bioavailability, limited effective targeting and potential cytotoxicity. Promising and versatile nano-scale drug-delivery systems include nanoparticles, nanocapsules, nanotubes, nanogels and dendrimers. They can be used to deliver both small-molecule drugs and various classes of biomacromolecules, such as peptides, proteins, plasmid DNA and synthetic oligodeoxynucleotides. Whereas traditional tissue-engineering scaffolds were based on hydrolytically degradable macroporous materials, current approaches emphasize the control over cell behaviors and tissue formation by nano-scale topography that closely mimics the natural extracellular matrix (ECM). The understanding that the natural ECM is a multifunctional nanocomposite motivated researchers to develop nanofibrous scaffolds through electrospinning or self-assembly. Nanocomposites containing nanocrystals have been shown to elicit active bone growth. Drug delivery and tissue engineering are closely related fields. In fact, tissue engineering can be viewed as a special case of drug delivery where the goal is to accomplish controlled delivery of mammalian cells. Controlled release of therapeutic factors in turn will enhance the efficacy of tissue engineering. From a materials

  18. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1988-01-01

    A decade long program to develop critical advanced composite technology in the areas of physical properties, structural concept and analysis, manufacturing, reliability, and life predictions is reviewed. Specific goals are discussed. The status of the chemical vapor deposition effects on carbon fiber properties; inelastic deformation of metal matrix laminates; fatigue damage in fibrous MMC laminates; delamination fracture toughness in thermoplastic matrix composites; and numerical analysis of composite micromechanical behavior are presented.

  19. Scaling Laws for van der Waals Interactions in Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Gobre, Vivekanand; Tkatchenko, Alexandre

    2014-03-01

    Van der Waals (vdW) forces originate from interactions between fluctuating multipoles in matter and play a significant role in the structure and stability of nanostructured materials. Many models used to describe vdW interactions in nanomaterials are based on a simple pairwise-additive approximation, neglecting the strong electrodynamic response effects caused by long-range fluctuations in matter. We develop and utilize an efficient microscopic method to demonstrate that vdW interactions in nanomaterials act at distances greater than typically assumed, and can be characterized by different scaling laws depending on the dimensionality and size of the system. Specifically, we study the behaviour of vdW interactions in single-layer and multilayer graphene, fullerenes of varying size, single-wall carbon nanotubes and graphene nanoribbons. As a function of nanostructure size, the van der Waals coefficients follow unusual trends for all of the considered systems, and deviate significantly from the conventionally employed pairwise-additive picture. We propose that the peculiar van der Waals interactions in nanostructured materials could be exploited to control their self-assembly.

  20. Nanostructured Materials for Room-Temperature Gas Sensors.

    PubMed

    Zhang, Jun; Liu, Xianghong; Neri, Giovanni; Pinna, Nicola

    2016-02-03

    Sensor technology has an important effect on many aspects in our society, and has gained much progress, propelled by the development of nanoscience and nanotechnology. Current research efforts are directed toward developing high-performance gas sensors with low operating temperature at low fabrication costs. A gas sensor working at room temperature is very appealing as it provides very low power consumption and does not require a heater for high-temperature operation, and hence simplifies the fabrication of sensor devices and reduces the operating cost. Nanostructured materials are at the core of the development of any room-temperature sensing platform. The most important advances with regard to fundamental research, sensing mechanisms, and application of nanostructured materials for room-temperature conductometric sensor devices are reviewed here. Particular emphasis is given to the relation between the nanostructure and sensor properties in an attempt to address structure-property correlations. Finally, some future research perspectives and new challenges that the field of room-temperature sensors will have to address are also discussed.

  1. Mechanical Properties of Nanostructured Materials Determined Through Molecular Modeling Techniques

    NASA Technical Reports Server (NTRS)

    Clancy, Thomas C.; Gates, Thomas S.

    2005-01-01

    The potential for gains in material properties over conventional materials has motivated an effort to develop novel nanostructured materials for aerospace applications. These novel materials typically consist of a polymer matrix reinforced with particles on the nanometer length scale. In this study, molecular modeling is used to construct fully atomistic models of a carbon nanotube embedded in an epoxy polymer matrix. Functionalization of the nanotube which consists of the introduction of direct chemical bonding between the polymer matrix and the nanotube, hence providing a load transfer mechanism, is systematically varied. The relative effectiveness of functionalization in a nanostructured material may depend on a variety of factors related to the details of the chemical bonding and the polymer structure at the nanotube-polymer interface. The objective of this modeling is to determine what influence the details of functionalization of the carbon nanotube with the polymer matrix has on the resulting mechanical properties. By considering a range of degree of functionalization, the structure-property relationships of these materials is examined and mechanical properties of these models are calculated using standard techniques.

  2. Assembling and properties of the polymer-particle nanostructured materials

    NASA Astrophysics Data System (ADS)

    Sheparovych, Roman

    Complementary properties of the soft and hard matter explain its common encounter in many natural and manmade applications. A combination of flexible organic macromolecules and hard mineral clusters results in new materials far advantageous than its constituents alone. In this work we study assembling of colloidal nanocrystals and polymers into complex nanostructures. Magnetism, surface wettability and adhesion comprise properties of interest for the obtained nanocomposites. Applying a magnetic field induces a reversible 1D ordering of the magnetically susceptible particles. This property was employed in the fabrication of the permanent chains of magnetite nanocrystals (d=15nm). In the assembling process the aligned particles were bound together using polyelectrolyte macromolecules. The basics of the binding process involved an electrostatic interaction between the positively charged polyelectrolyte and the negative surface of the particles (aqueous environment). Adsorption of the polymer molecules onto several adjacent particles in the aligned 1D aggregate results in the formation of the permanent particulate chains. Positive charges of the adsorbed polyelectrolyte molecules stabilize the dispersion of the obtained nanostructures in water. Magnetization measurements revealed that superparamagnetic nanoparticles, being assembled into 1D ordered structures, attain magnetic coercivity. This effect originates from the magnetostatic interaction between the neighboring magnetite nanocrystals. The preferable dipole alignment of the assembled nanoparticles is directed along the chain axis. Another system studied in this project includes polymer-particle responsive surface coatings. Tethered polymer chains and particles bearing different functionalities change surface properties upon restructuring of the composite layer. When the environment favors polymer swelling (good solvent), the polymer chains segregate to the surface and cover the particles. In the opposite case

  3. Composite materials: A compilation

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Design, analysis and fabrication techniques for boron-aluminum composite-structure technology is presented and a new method of joining different laminated composites without mechanical fasteners is proposed. Also discussed is a low-cost procedure for rigidifying expanded honeycomb tubing and piping simulations. A brief note on patent information is added.

  4. Strain-Detecting Composite Materials

    NASA Technical Reports Server (NTRS)

    Wallace, Terryl A. (Inventor); Smith, Stephen W. (Inventor); Piascik, Robert S. (Inventor); Horne, Michael R. (Inventor); Messick, Peter L. (Inventor); Alexa, Joel A. (Inventor); Glaessgen, Edward H. (Inventor); Hailer, Benjamin T. (Inventor)

    2016-01-01

    A composite material includes a structural material and a shape-memory alloy embedded in the structural material. The shape-memory alloy changes crystallographic phase from austenite to martensite in response to a predefined critical macroscopic average strain of the composite material. In a second embodiment, the composite material includes a plurality of particles of a ferromagnetic shape-memory alloy embedded in the structural material. The ferromagnetic shape-memory alloy changes crystallographic phase from austenite to martensite and changes magnetic phase in response to the predefined critical macroscopic average strain of the composite material. A method of forming a composite material for sensing the predefined critical macroscopic average strain includes providing the shape-memory alloy having an austenite crystallographic phase, changing a size and shape of the shape-memory alloy to thereby form a plurality of particles, and combining the structural material and the particles at a temperature of from about 100-700.degree. C. to form the composite material.

  5. When 1+1>2: Nanostructured composites for hard tissue engineering applications.

    PubMed

    Uskoković, Vuk

    2015-12-01

    Multicomponent, synergistic and multifunctional nanostructures have taken over the spotlight in the realm of biomedical nanotechnologies. The most prospective materials for bone regeneration today are almost exclusively composites comprising two or more components that compensate for the shortcomings of each one of them alone. This is quite natural in view of the fact that all hard tissues in the human body, except perhaps the tooth enamel, are composite nanostructures. This review article highlights some of the most prospective breakthroughs made in this research direction, with the hard tissues in main focus being those comprising bone, tooth cementum, dentin and enamel. The major obstacles to creating collagen/apatite composites modeled after the structure of bone are mentioned, including the immunogenicity of xenogeneic collagen and continuously failing attempts to replicate the biomineralization process in vitro. Composites comprising a polymeric component and calcium phosphate are discussed in light of their ability to emulate the soft/hard composite structure of bone. Hard tissue engineering composites created using hard material components other than calcium phosphates, including silica, metals and several types of nanotubes, are also discoursed on, alongside additional components deliverable using these materials, such as cells, growth factors, peptides, antibiotics, antiresorptive and anabolic agents, pharmacokinetic conjugates and various cell-specific targeting moieties. It is concluded that a variety of hard tissue structures in the body necessitates a similar variety of biomaterials for their regeneration. The ongoing development of nanocomposites for bone restoration will result in smart, theranostic materials, capable of acting therapeutically in direct feedback with the outcome of in situ disease monitoring at the cellular and subcellular scales. Progress in this research direction is expected to take us to the next generation of biomaterials

  6. Controlling Nanostructure for Catalytic and Electrochemical Energy Storage Materials

    NASA Astrophysics Data System (ADS)

    Mushove, Tapiwa

    Materials with precisely controlled nanostructures are needed to significantly enhance the efficiencies of next-generation chemical conversion and energy storage systems. This dissertation employs light and electrochemical techniques to control nanostructure of catalytic and electrochemical energy storage materials. We also define nanostructure-function relationships for three material systems. This information could help the design and synthesis of materials with superior performance. Single layer (SL), multilayer (ML), and wave-like (WL) hematite nanotube arrays (NA) were fabricated via the electrochemical anodization of iron foils. The films' current responses during fabrication were tracked, allowing for the characterization of NA growth. Four distinct stages were identified: an ohmic response stage, an oxide film formation stage, a chemical dissolution stage, and a steady-state growth stage. Morphological and photoelectrochemical properties of the hematite electrodes were characterized and correlated with their photocatalytic performances. The IPCE of the WLNA at 350 nm was ~3 times that of the SLNA, and ~12 times that of the MLNA. Charge carrier transport and the active electrochemical surface area of the different morphologies were significant determinants of photocatalytic performance. Niobium pentoxide (Nb2O5) NA and planar electrodes were fabricated via a similar anodization technique. The Li+ intercalation behavior of the electrodes was characterized. NA electrodes exhibited a four-fold improvement in charge storage capacity and higher rate capabilities relative to planar electrodes due to larger surface areas and shorter ion diffusion lengths in the NA. Light of different wavelengths was used to control the photodeposition of noble metals on semiconducting tungsten trioxide. The metal nanoparticle sizes and weight loadings were functions of the illumination time, while geometries were controlled by the wavelength. Intrinsic variations in the plasmonic

  7. Hierarchical Assembly of Multifunctional Oxide-based Composite Nanostructures for Energy and Environmental Applications

    PubMed Central

    Gao, Pu-Xian; Shimpi, Paresh; Gao, Haiyong; Liu, Caihong; Guo, Yanbing; Cai, Wenjie; Liao, Kuo-Ting; Wrobel, Gregory; Zhang, Zhonghua; Ren, Zheng; Lin, Hui-Jan

    2012-01-01

    Composite nanoarchitectures represent a class of nanostructured entities that integrates various dissimilar nanoscale building blocks including nanoparticles, nanowires, and nanofilms toward realizing multifunctional characteristics. A broad array of composite nanoarchitectures can be designed and fabricated, involving generic materials such as metal, ceramics, and polymers in nanoscale form. In this review, we will highlight the latest progress on composite nanostructures in our research group, particularly on various metal oxides including binary semiconductors, ABO3-type perovskites, A2BO4 spinels and quaternary dielectric hydroxyl metal oxides (AB(OH)6) with diverse application potential. Through a generic template strategy in conjunction with various synthetic approaches— such as hydrothermal decomposition, colloidal deposition, physical sputtering, thermal decomposition and thermal oxidation, semiconductor oxide alloy nanowires, metal oxide/perovskite (spinel) composite nanowires, stannate based nanocompostes, as well as semiconductor heterojunction—arrays and networks have been self-assembled in large scale and are being developed as promising classes of composite nanoarchitectures, which may open a new array of advanced nanotechnologies in solid state lighting, solar absorption, photocatalysis and battery, auto-emission control, and chemical sensing. PMID:22837702

  8. Hierarchical assembly of multifunctional oxide-based composite nanostructures for energy and environmental applications.

    PubMed

    Gao, Pu-Xian; Shimpi, Paresh; Gao, Haiyong; Liu, Caihong; Guo, Yanbing; Cai, Wenjie; Liao, Kuo-Ting; Wrobel, Gregory; Zhang, Zhonghua; Ren, Zheng; Lin, Hui-Jan

    2012-01-01

    Composite nanoarchitectures represent a class of nanostructured entities that integrates various dissimilar nanoscale building blocks including nanoparticles, nanowires, and nanofilms toward realizing multifunctional characteristics. A broad array of composite nanoarchitectures can be designed and fabricated, involving generic materials such as metal, ceramics, and polymers in nanoscale form. In this review, we will highlight the latest progress on composite nanostructures in our research group, particularly on various metal oxides including binary semiconductors, ABO(3)-type perovskites, A(2)BO(4) spinels and quaternary dielectric hydroxyl metal oxides (AB(OH)(6)) with diverse application potential. Through a generic template strategy in conjunction with various synthetic approaches- such as hydrothermal decomposition, colloidal deposition, physical sputtering, thermal decomposition and thermal oxidation, semiconductor oxide alloy nanowires, metal oxide/perovskite (spinel) composite nanowires, stannate based nanocompostes, as well as semiconductor heterojunction-arrays and networks have been self-assembled in large scale and are being developed as promising classes of composite nanoarchitectures, which may open a new array of advanced nanotechnologies in solid state lighting, solar absorption, photocatalysis and battery, auto-emission control, and chemical sensing.

  9. In situ transmission electron microscopy experimentation of nanostructured materials

    NASA Astrophysics Data System (ADS)

    Alducin, Diego

    Due to the remarkable mechanical and electrical properties some nanostructured materials possess, it is important to be able to quantitatively characterize how these materials react under different types of stimulus. In situ transmission electron microscopy is a unique technique that allows the user to fully observe and record the crystallographic behavior of such materials undergoing a variety of tests. The crystallographic orientations silver nanowires were mapped in order to understand the structure and facets due to its geometry. Measuring the toughness and yield of the material led us to understand the anisotropic behavior of AgNWs. Depending on whether a load is applied to either a boundary between facets or on a facet will change the mechanical strength of the nanowire. By measuring the resistivity of the this material during deformation has also led us to understand that the intrinsic defects in the crystal structure of nanowires will change the way the material reacts to an electric potential. We have been also able to completely map the crystallographic orientations of very complex geometries of gold nanoparticles and characterize the weak forces involved in the manipulation if these nanoparticles. Finally, the elasticity of MoS2 was tested and found to be exponentially dependent upon the thickness of the nanosheets. However, the resistivity of this material does not seem to be affected by any type of deformation it is subjected to. The complete categorization of how materials interact with external stimulus while comparing the changes observed in its crystal structure is essential to understanding the underlying properties of nanostructured materials, which would not be possible without in situ transmisison electron microscopy experimentation.

  10. Vanadium-based nanostructure materials for secondary lithium battery applications

    NASA Astrophysics Data System (ADS)

    Tan, Hui Teng; Rui, Xianhong; Sun, Wenping; Yan, Qingyu; Lim, Tuti Mariana

    2015-08-01

    Vanadium-based materials, such as V2O5, LiV3O8, VO2(B) and Li3V2(PO4)3 are compounds that share the characteristic of intercalation chemistry. Their layered or open frameworks allow facile ion movement through the interspaces, making them promising cathodes for LIB applications. To bypass bottlenecks occurring in the electrochemical performances of vanadium-based cathodes that derive from their intrinsic low electrical conductivity and ion diffusion coefficients, nano-engineering strategies have been implemented to ``create'' newly emerging properties that are unattainable at the bulk solid level. Integrating this concept into vanadium-based cathodes represents a promising way to circumvent the aforementioned problems as nanostructuring offers potential improvements in electrochemical performances by providing shorter mass transport distances, higher electrode/electrolyte contact interfaces, and better accommodation of strain upon lithium uptake/release. The significance of nanoscopic architectures has been exemplified in the literature, showing that the idea of developing vanadium-based nanostructures is an exciting prospect to be explored. In this review, we will be casting light on the recent advances in the synthesis of nanostructured vanadium-based cathodes. Furthermore, efficient strategies such as hybridization with foreign matrices and elemental doping are introduced as a possible way to boost their electrochemical performances (e.g., rate capability, cycling stability) to a higher level. Finally, some suggestions relating to the perspectives for the future developments of vanadium-based cathodes are made to provide insight into their commercialization.

  11. Thin film thermocouples for thermoelectric characterization of nanostructured materials

    NASA Astrophysics Data System (ADS)

    Grayson, Matthew; Zhou, Chuanle; Varrenti, Andrew; Chyung, Seung Hye; Long, Jieyi; Memik, Seda

    2011-03-01

    The increased use of nanostructured materials as thermoelectrics requires reliable and accurate characterization of the anisotropic thermal coefficients of small structures, such as superlattices and quantum wire networks. Thin evaporated metal films can be used to create thermocouples with a very small thermal mass and low thermal conductivity, in order to measure thermal gradients on nanostructures and thereby measure the thermal conductivity and the Seebeck coefficient of the nanostructure. In this work we confirm the known result that thin metal films have lower Seebeck coefficients than bulk metals, and we also calibrate the Seebeck coefficient of a thin-film Ni/Cr thermocouple with 50 nm thickness, showing it to have about 1/4 the bulk value. We demonstrate reproducibility of this thin-filmSeebeck coefficient on multiple substrates, and we show that this coefficient does, in fact, change as a function of film thickness. We will discuss prototype measurement designs and preliminary work as to how these thin films can be used to study both Seebeck coefficients and thermal conductivities of superlattices in various geometries. The same technology can in principle be used on integrated circuits for thermal mapping, under the name ``Integrated On-Chip Thermocouple Array'' (IOTA).

  12. Self-assembled peptide nanostructures for functional materials.

    PubMed

    Ekiz, Melis Sardan; Cinar, Goksu; Khalily, Mohammad Aref; Guler, Mustafa O

    2016-10-07

    Nature is an important inspirational source for scientists, and presents complex and elegant examples of adaptive and intelligent systems created by self-assembly. Significant effort has been devoted to understanding these sophisticated systems. The self-assembly process enables us to create supramolecular nanostructures with high order and complexity, and peptide-based self-assembling building blocks can serve as suitable platforms to construct nanostructures showing diverse features and applications. In this review, peptide-based supramolecular assemblies will be discussed in terms of their synthesis, design, characterization and application. Peptide nanostructures are categorized based on their chemical and physical properties and will be examined by rationalizing the influence of peptide design on the resulting morphology and the methods employed to characterize these high order complex systems. Moreover, the application of self-assembled peptide nanomaterials as functional materials in information technologies and environmental sciences will be reviewed by providing examples from recently published high-impact studies.

  13. Fabrication of bioinspired nanostructured materials via colloidal self-assembly

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Han

    Through millions of years of evolution, nature creates unique structures and materials that exhibit remarkable performance on mechanicals, opticals, and physical properties. For instance, nacre (mother of pearl), bone and tooth show excellent combination of strong minerals and elastic proteins as reinforced materials. Structured butterfly's wing and moth's eye can selectively reflect light or absorb light without dyes. Lotus leaf and cicada's wing are superhydrophobic to prevent water accumulation. The principles of particular biological capabilities, attributed to the highly sophisticated structures with complex hierarchical designs, have been extensively studied. Recently, a large variety of novel materials have been enabled by natural-inspired designs and nanotechnologies. These advanced materials will have huge impact on practical applications. We have utilized bottom-up approaches to fabricate nacre-like nanocomposites with "brick and mortar" structures. First, we used self-assembly processes, including convective self-assembly, dip-coating, and electrophoretic deposition to form well oriented layer structure of synthesized gibbsite (aluminum hydroxide) nanoplatelets. Low viscous monomer was permeated into layered nanoplatelets and followed by photo-curing. Gibbsite-polymer composite displays 2 times higher tensile strength and 3 times higher modulus when compared with pure polymer. More improvement occurred when surface-modified gibbsite platelets were cross-linked with the polymer matrix. We observed ˜4 times higher strength and nearly 1 order of magnitude higher modulus than pure polymer. To further improve the mechanical strength and toughness of inorganicorganic nanocomposites, we exploited ultrastrong graphene oxide (GO), a single atom thick hexagonal carbon sheet with pendant oxidation groups. GO nanocomposite is made by co-filtrating GO/polyvinyl alcohol suspension on 0.2 im pore-sized membrane. It shows ˜2 times higher strength and ˜15 times higher

  14. Composite structural materials. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1980-01-01

    The use of filamentary composite materials in the design and construction of primary aircraft structures is considered with emphasis on efforts to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, and reliability and life prediction. The redesign of a main spar/rib region on the Boeing 727 elevator near its actuator attachment point is discussed. A composite fabrication and test facility is described as well as the use of minicomputers for computer aided design. Other topics covered include (1) advanced structural analysis methids for composites; (2) ultrasonic nondestructive testing of composite structures; (3) optimum combination of hardeners in the cure of epoxy; (4) fatigue in composite materials; (5) resin matrix characterization and properties; (6) postbuckling analysis of curved laminate composite panels; and (7) acoustic emission testing of composite tensile specimens.

  15. Anisotropic Thermal Properties of Nanostructured Magnetic, Carbon and Hybrid Magnetic - Carbon Materials

    NASA Astrophysics Data System (ADS)

    Ramirez, Sylvester

    In this dissertation research we investigated thermal properties of three groups of nanostructured materials: (i) magnetic; (ii) reduced graphene oxide films; and (iii) hybrid magnetic -- graphite -- graphene composites. The thermal measurements were conducted using the transient "hot disk" and "laser flash" techniques. The rare-earth free nanostructured SrFe12O19 permanent magnets were produced by the current activated pressure assisted densification technique. The thermal conductivity of the nanostructured bulk magnets was found to range from 3.8 to 5.6 W/mK for the in-plane and 2.36 W/mk to 2.65 W/mK for the cross-plane directions, respectively. The heat conduction was dominated by phonons near the room temperature. The anisotropy of heat conduction was explained by the brick-like alignment of crystalline grains with the longer grain size in-plane direction. The thermal conductivity scales up with the average grain size and mass density of the material revealing weak temperature dependence. Using the nanostructured ferromagnetic Fe3O4 composites as an example system, we incorporated graphene and graphite fillers into magnetic material without changing their morphology. It was demonstrated that addition of 5 wt. % of equal mixture of graphene and graphite flakes to the composite results in a factor of x2.6 enhancement of the thermal conductivity without significant degradation of the saturation magnetization. We investigated thermal conductivity of free-standing reduced graphene oxide films subjected to a high-temperature treatment of up to 1000°C. It was found that the high-temperature annealing dramatically increased the in-plane thermal conductivity, K, of the films from ˜3 W/mK to ˜61 W/mK at room temperature. The cross-plane thermal conductivity, K⊥, revealed an interesting opposite trend of decreasing to a very small value of ˜0.09 W/mK in the reduced graphene oxide films annealed at 1000°C. The obtained films demonstrated an exceptionally strong

  16. A new approach to the fabrication of ``smart`` near-surface nanostructure composites

    SciTech Connect

    Gea, L.; Honda, S.; Boatner, L.A.; Haynes, T.E.; Sales, B.C.; Modine, F.A.; Meldrum, A.; Budai, J.D.; Beckers, L.

    1998-01-01

    A new method for the formation of smart near-surface nanoscale composites has been developed. In this approach, small precipitates of active phases are embedded in the near-surface region of the material that is to be modified by a combination of ion implantation and thermal processing. The dispersion, concentration, and microstructure of the nanocrystals formed in the substrate material can be tailored through a careful choice of processing parameters - making this approach well suited to high value added, high technology applications. The applicability of this approach to forming smart surfaces on otherwise inactive materials was established in the case of VO{sup 2} precipitates which were embedded in Al{sub 2}O{sub 3} single crystals to create a medium suitable for optical applications--including optical data storage. Most recently, this concept has been extended to the fabrication of magnetic field sensitive nanostructured surfaces by forming magnetostrictive precipitates of materials such as Ni or RFe{sub 2} (with R = Tm, Tb, Sm) that are embedded in various single crystal oxide hosts. These nanostructured, active surface composites have been characterized using XRD, RBS, TEM, and magneto-optical techniques.

  17. Multiscale architectured materials with composition and grain size gradients manufactured using high-pressure torsion

    PubMed Central

    Kang, Ji Yun; Kim, Jung Gi; Park, Hyo Wook; Kim, Hyoung Seop

    2016-01-01

    The concept of multiscale architectured materials is established using composition and grain size gradients. Composition-gradient nanostructured materials are produced from coarse grained interstitial free steels via carburization and high-pressure torsion. Quantitative analyses of the dislocation density using X-ray diffraction and microstructural studies clearly demonstrate the gradients of the dislocation density and grain size. The mechanical properties of the gradient materials are compared with homogeneous nanostructured carbon steel without a composition gradient in an effort to investigate the gradient effect. Based on the above observations, the potential of multiscale architecturing to open a new material property is discussed. PMID:27229160

  18. Nanostructured BN-Mg composites: features of interface bonding and mechanical properties.

    PubMed

    Kvashnin, Dmitry G; Krasheninnikov, Arkady V; Shtansky, Dmitry; Sorokin, Pavel B; Golberg, Dmitri

    2016-01-14

    Magnesium (Mg) is one of the lightest industrially used metals. However, wide applications of Mg-based components require a substantial enhancement of their mechanical characteristics. This can be achieved by introducing small particles or fibers into the metal matrix. Using first-principles calculations, we investigate the stability and mechanical properties of a nanocomposite made of magnesium reinforced with boron nitride (BN) nanostructures (BN nanotubes and BN monolayers). We show that boron vacancies at the BN/Mg interface lead to a substantial increase in BN/Mg bonding establishing an efficient route towards the development of BN/Mg composite materials with enhanced mechanical properties.

  19. Structure and properties of composites based chitosan and carbon nanostructures: atomistic and coarse-grained simulation

    NASA Astrophysics Data System (ADS)

    Glukhova, O. E.; Kolesnikova, A. S.; Grishina, O. A.; Slepchenkov, M. M.

    2015-03-01

    At the present time actual task of the modern materials is the creation of biodegradable biocompatible composite materials possessing high strength properties for medical purposes. One of the most promising biomaterials from a position of creation on their basis super strong nanofibres is chitosan. The aim of this work is a theoretical study of the structural features and physico-mechanical properties of biocomposite materials based on chitosan and carbon nanostructures. As matrix nanocomposite we considered various carbon nano-objects, namely carbon nanotubes and graphene. Using the developed original software complex KVAZAR we built atomistic and coarse-grained models of the biocomposite material. To identify regularities of influence of the configuration of the carbon matrix on the mechanical and electronic properties of biocomposite we carried out a series of numerical experiments using a classical algorithm of molecular dynamics and semi-empirical methods. The obtained results allow us to suggest that the generated biocomposite based on chitosan and carbon nanostructures has high stability and strength characteristics. Such materials can be used in biomedicine as a base material for creating of artificial limbs.

  20. Soft nanostructured films for directing the assembly of functional materials

    NASA Astrophysics Data System (ADS)

    Steer, D.; Kang, M.; Leal, C.

    2017-04-01

    Lipids are a class of biological small molecules with hydrophilic and hydrophobic constituents forming the structural membranes in cells. Over the past century an extensive understanding of lipid biology and biophysics has been developed illuminating lipids as an intricate, highly tunable, and hierarchical soft-matter system. In addition to serving as cell membrane models, lipids have been investigated as microphase separated structures in aqueous solutions. In terms of applications lipids have been realized as powerful structural motifs for the encapsulation and cellular delivery of genetic material. More recently, lipids have also revealed promise as thin film materials, exhibiting long-range periodic nano-scale order and tunable orientation. In this review we summarize the pertinent understanding of lipid nanostructure development in bulk aqueous systems followed by the current and potential perturbations to these results induced by introduction of a substrate. These effects are punctuated by a summary of our published results in the field of lipid thin films with added nucleic acids and key results introducing hard materials into lipid nanostructured substrates.

  1. Soft nanostructured films for directing the assembly of functional materials.

    PubMed

    Steer, D; Kang, M; Leal, C

    2017-04-07

    Lipids are a class of biological small molecules with hydrophilic and hydrophobic constituents forming the structural membranes in cells. Over the past century an extensive understanding of lipid biology and biophysics has been developed illuminating lipids as an intricate, highly tunable, and hierarchical soft-matter system. In addition to serving as cell membrane models, lipids have been investigated as microphase separated structures in aqueous solutions. In terms of applications lipids have been realized as powerful structural motifs for the encapsulation and cellular delivery of genetic material. More recently, lipids have also revealed promise as thin film materials, exhibiting long-range periodic nano-scale order and tunable orientation. In this review we summarize the pertinent understanding of lipid nanostructure development in bulk aqueous systems followed by the current and potential perturbations to these results induced by introduction of a substrate. These effects are punctuated by a summary of our published results in the field of lipid thin films with added nucleic acids and key results introducing hard materials into lipid nanostructured substrates.

  2. Nanostructured Materials Utilized in Biopolymer-based Plastics for Food Packaging Applications.

    PubMed

    Ghanbarzadeh, Babak; Oleyaei, Seyed Amir; Almasi, Hadi

    2015-01-01

    Most materials currently used for food packaging are nondegradable, generating environmental problems. Several biopolymers have been exploited to develop materials for ecofriendly food packaging. However, the use of biopolymers has been limited because of their usually poor mechanical and barrier properties, which may be improved by adding reinforcing compounds (fillers), forming composites. Most reinforced materials present poor matrix-filler interactions, which tend to improve with decreasing filler dimensions. The use of fillers with at least one nanoscale dimension (nanoparticles) produces nanocomposites. Nanoparticles have proportionally larger surface area than their microscale counterparts, which favors the filler-matrix interactions and the performance of the resulting material. Besides nanoreinforcements, nanoparticles can have other functions when added to a polymer, such as antimicrobial activity, etc. in this review paper, the structure and properties of main kinds of nanostructured materials which have been studied to use as nanofiller in biopolymer matrices are overviewed, as well as their effects and applications.

  3. High-strength and high-ductility nanostructured and amorphous metallic materials.

    PubMed

    Kou, Hongning; Lu, Jian; Li, Ying

    2014-08-20

    The development of materials with dual properties of high strength and high ductility has been a constant challenge since the foundation of the materials science discipline. The rapid progress of nanotechnology in recent decades has further brought this challenge to a new era. This Research News highlights a few newly developed strategies to optimize advanced nanomaterials and metallic glasses with exceptional dual mechanical properties of high strength and high ductility. A general concept of strain non-localization is presented to describe the role of multiscale (i.e., macroscale, microscale, nanoscale, and atomic scale) heterogeneities in the ductility enhancement of materials reputed to be intrinsically brittle, such as nanostructured metallic materials and bulk metallic glasses. These nanomaterials clearly form a new group of materials that display an extraordinary relationship between yield strength and the uniform elongation with the same chemical composition. Several other examples of nanomaterials such as those reinforced by nanoprecipitates will also be described.

  4. Computational design of surfaces, nanostructures and optoelectronic materials

    NASA Astrophysics Data System (ADS)

    Choudhary, Kamal

    Properties of engineering materials are generally influenced by defects such as point defects (vacancies, interstitials, substitutional defects), line defects (dislocations), planar defects (grain boundaries, free surfaces/nanostructures, interfaces, stacking faults) and volume defects (voids). Classical physics based molecular dynamics and quantum physics based density functional theory can be useful in designing materials with controlled defect properties. In this thesis, empirical potential based molecular dynamics was used to study the surface modification of polymers due to energetic polyatomic ion, thermodynamics and mechanics of metal-ceramic interfaces and nanostructures, while density functional theory was used to screen substituents in optoelectronic materials. Firstly, polyatomic ion-beams were deposited on polymer surfaces and the resulting chemical modifications of the surface were examined. In particular, S, SC and SH were deposited on amorphous polystyrene (PS), and C2H, CH3, and C3H5 were deposited on amorphous poly (methyl methacrylate) (PMMA) using molecular dynamics simulations with classical reactive empirical many-body (REBO) potentials. The objective of this work was to elucidate the mechanisms by which the polymer surface modification took place. The results of the work could be used in tailoring the incident energy and/or constituents of ion beam for obtaining a particular chemistry inside the polymer surface. Secondly, a new Al-O-N empirical potential was developed within the charge optimized many body (COMB) formalism. This potential was then used to examine the thermodynamic stability of interfaces and mechanical properties of nanostructures composed of aluminum, its oxide and its nitride. The potentials were tested for these materials based on surface energies, defect energies, bulk phase stability, the mechanical properties of the most stable bulk phase, its phonon properties as well as with a genetic algorithm based evolution theory of

  5. Novel Nanostructures Enabled by On-Wire Lithography: New Materials and Architectures

    NASA Astrophysics Data System (ADS)

    Mangelson, Bryan Farrin

    Advances in nanotechnology enable researches to study and utilize new materials properties and are in large part driven by development and improvement of methods for synthesizing nanostructures. This dissertation discuses the advancement of one such method, On-Wire Lithography (OWL), a template directed electrochemical nanostructure synthesis technique. Chapter 2 is a demonstration of what was the first extension of OWL to an inorganic semiconductor material, namely anatase TiO2. The combination of this material with plasmonically active Au disk dimers results in the formation of composite plasmonic-semiconducting nanowires. This is accomplished via the sol-gel electrochemical deposition of Ti precursors on the Au dimers, followed by the selective chemical etching of Ni, and annealing of the Ti gel to form the anatase phase of TiO2. Chapter 3 extends the OWL toolbox to include Pd metal as a material. It is also shown that by taking advantage of the ability of OWL to form small gaps within the nanowire structure, a Pd based hydrogen gas sensor can be achieved. Chapter 4 shows the power of OWL for controlling the geometric architecture of nanowire-based structures. By introducing multiple nanowire dimers within the same structure, a single nanostructure exhibiting multiple plasmon resonances can be made. The spectral response of these structures is tailorable allowing one to create broadband absorbing structures. It is also demonstrated that by precise placement of the nanowire dimers with respect to each other a near field coupling effect can be observed which increases the total extinction of the structure by 12%. In Chapter 5 a composite plasmonic-semiconductor material composed of OWL fabricated nanowire dimers within sheets of Anatase TiO2 is fabricated. Despite the harsh conditions necessary to synthesize crystalline TiO2 sheets, the gapped nanostructures remain intact. Additionally, the optical properties of these structures can be tailored to produce

  6. Design and characterization of a conductive nanostructured polypyrrole-polycaprolactone coated magnesium/PLGA composite for tissue engineering scaffolds.

    PubMed

    Liu, Haixia; Wang, Ran; Chu, Henry K; Sun, Dong

    2015-09-01

    A novel biodegradable and conductive composite consisting of magnesium (Mg), polypyrrole-block-ploycaprolactone (PPy-PCL), and poly(lactic-co-glycolic acid) (PLGA) is synthesized in a core-shell-skeleton manner for tissue engineering applications. Mg particles in the composite are first coated with a conductive nanostructured PPy-PCL layer for corrosion resistance via the UV-induced photopolymerization method. PLGA matrix is then added to tailor the biodegradability of the resultant composite. Composites with different composition ratios are examined through experiments, and their material properties are characterized. The in vitro experiments on culture of 293FT-GFP cells show that the composites are suitable for cell growth and culture. Biodegradability of the composite is also evaluated. By adding PLGA matrix to the composite, the degrading time of the composite can last for more than eight weeks, hence providing a longer period for tissue formation as compared to Mg composites or alloys. The findings of this research will offer a new opportunity to utilize a conductive, nanostructured-coated Mg/PLGA composite as the scaffold material for implants and tissue regeneration.

  7. Composite Materials for Maxillofacial Prostheses.

    DTIC Science & Technology

    1979-08-01

    block number) MAXILLOFACIAL PROSTHESES; PROSTHETIC MATERIALS; MICROCAPSULES ; SOFT FILLERS; ELASTuMER COMPOSITES 20,_ ABSTRACT ’Continue on reverse side...approaches were pursued toward making such microcapsules . One approach involves coaxial extrusion of a catalyzed elastomer precursor and core liquid into a...fabrication of maxillofacial prostheses. The projected composite systems are elastomeric-shelled, liquid-filled microcapsules . Two experimental approaches were

  8. Composite structural materials. [aircraft applications

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1981-01-01

    The development of composite materials for aircraft applications is addressed with specific consideration of physical properties, structural concepts and analysis, manufacturing, reliability, and life prediction. The design and flight testing of composite ultralight gliders is documented. Advances in computer aided design and methods for nondestructive testing are also discussed.

  9. Nondestructive Characterization of Composite Materials

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.

    1993-01-01

    Increasingly, composite materials are applied to fracture-critical structures of aircraft and spacecraft...Ultrasonics offer the most capable inspection technology and recently developed techniques appear to improve this technology significantly... Recent progress in ultrasonic NDE of composites will be reviewed.

  10. Comprehensive Enhancement of Nanostructured Lithium-Ion Battery Cathode Materials via Conformal Graphene Dispersion.

    PubMed

    Chen, Kan-Sheng; Xu, Rui; Luu, Norman S; Secor, Ethan B; Hamamoto, Koichi; Li, Qianqian; Kim, Soo; Sangwan, Vinod K; Balla, Itamar; Guiney, Linda M; Seo, Jung-Woo T; Yu, Xiankai; Liu, Weiwei; Wu, Jinsong; Wolverton, Chris; Dravid, Vinayak P; Barnett, Scott A; Lu, Jun; Amine, Khalil; Hersam, Mark C

    2017-04-12

    Efficient energy storage systems based on lithium-ion batteries represent a critical technology across many sectors including consumer electronics, electrified transportation, and a smart grid accommodating intermittent renewable energy sources. Nanostructured electrode materials present compelling opportunities for high-performance lithium-ion batteries, but inherent problems related to the high surface area to volume ratios at the nanometer-scale have impeded their adoption for commercial applications. Here, we demonstrate a materials and processing platform that realizes high-performance nanostructured lithium manganese oxide (nano-LMO) spinel cathodes with conformal graphene coatings as a conductive additive. The resulting nanostructured composite cathodes concurrently resolve multiple problems that have plagued nanoparticle-based lithium-ion battery electrodes including low packing density, high additive content, and poor cycling stability. Moreover, this strategy enhances the intrinsic advantages of nano-LMO, resulting in extraordinary rate capability and low temperature performance. With 75% capacity retention at a 20C cycling rate at room temperature and nearly full capacity retention at -20 °C, this work advances lithium-ion battery technology into unprecedented regimes of operation.

  11. Improving the capacity of sodium ion battery using a virus-templated nanostructured composite cathode.

    PubMed

    Moradi, Maryam; Li, Zheng; Qi, Jifa; Xing, Wenting; Xiang, Kai; Chiang, Yet-Ming; Belcher, Angela M

    2015-05-13

    In this work we investigated an energy-efficient biotemplated route to synthesize nanostructured FePO4 for sodium-based batteries. Self-assembled M13 viruses and single wall carbon nanotubes (SWCNTs) have been used as a template to grow amorphous FePO4 nanoparticles at room temperature (the active composite is denoted as Bio-FePO4-CNT) to enhance the electronic conductivity of the active material. Preliminary tests demonstrate a discharge capacity as high as 166 mAh/g at C/10 rate, corresponding to composition Na0.9FePO4, which along with higher C-rate tests show this material to have the highest capacity and power performance reported for amorphous FePO4 electrodes to date.

  12. Improving the Capacity of Sodium Ion Battery Using a Virus-Templated Nanostructured Composite Cathode

    SciTech Connect

    Moradi, M; Li, Z; Qi, JF; Xing, WT; Xiang, K; Chiang, YM; Belcher, AM

    2015-05-01

    In this work we investigated an energy-efficient biotemplated route to synthesize nanostructured FePO4 for sodium-based batteries. Self-assembled M13 viruses and single wall carbon nanotubes (SWCNTs) have been used as a template to grow amorphous FePO4 nanoparticles at room temperature (the active composite is denoted as Bio-FePO4-CNT) to enhance the electronic conductivity of the active material. Preliminary tests demonstrate a discharge capacity as high as 166 mAh/g at C/10 rate, corresponding to composition Na0.9FePO4, which along with higher C-rate tests show this material to have the highest capacity and power performance reported for amorphous FePO4 electrodes to date.

  13. Carbon nanotube composite materials

    DOEpatents

    O'Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  14. Novel hybrid nanostructured materials of magnetite nanoparticles and pectin

    NASA Astrophysics Data System (ADS)

    Sahu, Saurabh; Dutta, Raj Kumar

    2011-04-01

    A novel hybrid nanostructured material comprising superparamagnetic magnetite nanoparticles (MNPs) and pectin was synthesized by crosslinking with Ca2+ ions to form spherical calcium pectinate nanostructures, referred as MCPs, which were typically found to be 100-150 nm in size in dried condition, confirmed from transmission electron microscopy and scanning electron microscopy. The uniform size distribution was revealed from dynamic light scattering measurement. In aqueous medium the MCPs showed swelling behavior with an average size of 400 nm. A mechanism of formation of spherical MCPs is outlined constituting a MNP-pectin interface encapsulated by calcium pectinate at the periphery, by using an array of characterization techniques like zeta potential, thermogravimetry, Fourier transformed infrared and X-ray photoelectron spectroscopy. The MCPs were stable in simulated gastrointestinal fluid and ensured minimal loss of magnetic material. They exhibited superparamagnetic behavior, confirmed from zero field cooled and field cooled profiles and showed high saturation magnetization (Ms) of 46.21 emu/g at 2.5 T and 300 K. Ms decreased with increasing precursor pectin concentrations, attributed to quenching of magnetic moments by formation of a magnetic dead layer on the MNPs.

  15. Nanomanufacturing : nano-structured materials made layer-by-layer.

    SciTech Connect

    Cox, James V.; Cheng, Shengfeng; Grest, Gary Stephen; Tjiptowidjojo, Kristianto; Reedy, Earl David, Jr.; Fan, Hongyou; Schunk, Peter Randall; Chandross, Michael Evan; Roberts, Scott A.

    2011-10-01

    Large-scale, high-throughput production of nano-structured materials (i.e. nanomanufacturing) is a strategic area in manufacturing, with markets projected to exceed $1T by 2015. Nanomanufacturing is still in its infancy; process/product developments are costly and only touch on potential opportunities enabled by growing nanoscience discoveries. The greatest promise for high-volume manufacturing lies in age-old coating and imprinting operations. For materials with tailored nm-scale structure, imprinting/embossing must be achieved at high speeds (roll-to-roll) and/or over large areas (batch operation) with feature sizes less than 100 nm. Dispersion coatings with nanoparticles can also tailor structure through self- or directed-assembly. Layering films structured with these processes have tremendous potential for efficient manufacturing of microelectronics, photovoltaics and other topical nano-structured devices. This project is designed to perform the requisite R and D to bring Sandia's technology base in computational mechanics to bear on this scale-up problem. Project focus is enforced by addressing a promising imprinting process currently being commercialized.

  16. Thermal Characterization of Nanostructures and Advanced Engineered Materials

    NASA Astrophysics Data System (ADS)

    Goyal, Vivek Kumar

    Continuous downscaling of Si complementary metal-oxide semiconductor (CMOS) technology and progress in high-power electronics demand more efficient heat removal techniques to handle the increasing power density and rising temperature of hot spots. For this reason, it is important to investigate thermal properties of materials at nanometer scale and identify materials with the extremely large or extremely low thermal conductivity for applications as heat spreaders or heat insulators in the next generation of integrated circuits. The thin films used in microelectronic and photonic devices need to have high thermal conductivity in order to transfer the dissipated power to heat sinks more effectively. On the other hand, thermoelectric devices call for materials or structures with low thermal conductivity because the performance of thermoelectric devices is determined by the figure of merit Z=S2sigma/K, where S is the Seebeck coefficient, K and sigma are the thermal and electrical conductivity, respectively. Nanostructured superlattices can have drastically reduced thermal conductivity as compared to their bulk counterparts making them promising candidates for high-efficiency thermoelectric materials. Other applications calling for thin films with low thermal conductivity value are high-temperature coatings for engines. Thus, materials with both high thermal conductivity and low thermal conductivity are technologically important. The increasing temperature of the hot spots in state-of-the-art chips stimulates the search for innovative methods for heat removal. One promising approach is to incorporate materials, which have high thermal conductivity into the chip design. Two suitable candidates for such applications are diamond and graphene. Another approach is to integrate the high-efficiency thermoelectric elements for on-spot cooling. In addition, there is strong motivation for improved thermal interface materials (TIMs) for heat transfer from the heat-generating chip

  17. Synthesis and processing of nanostructured BN and BN/Ti composites

    NASA Astrophysics Data System (ADS)

    Horvath, Robert Steven

    Superhard materials, such as cubic-BN, are widely used in machine tools, grinding wheels, and abrasives. Low density combined with high hardness makes c-BN and its composites attractive candidate materials for personnel and vehicular armor. However, improvements in toughness, and ballistic-impact performance, are needed to meet anticipated performance requirements. To achieve such improvements, we have targeted for development nanostructured c-BN, and its composites with Ti. Current research utilizes an experimental high pressure/high temperature (HPHT) method to produce these materials on a laboratory scale. Results from this work should transfer well into the industrial arena, utilizing high-tonnage presses used in the production of synthetic diamond and c-BN. Progress has been made in: (1) HPHT synthesis of cBN powder using Mg as catalyst; (2) HPHT consolidation of cBN powder to produce nanostructured cBN; (3) reactive-HPHT consolidation of mixed cBN/Ti powder to produce nanostructured Ti- or TiB2/TiN-bonded cBN; and (4) reactive-HPHT consolidation of mixed hBN/Ti powder to produce nanostructured Ti-bonded TiB2/TiN or TiB2/TiN. Even so, much remains to be done to lay a firm scientific foundation to enable the reproducible fabrication of large-area panels for armor applications. To this end, Rutgers has formed a partnership with a major producer of hard and superhard materials. The ability to produce hard and superhard nanostructured composites by reacting cBN or hBN with Ti under high pressure also enables multi-layered structures to be developed. Such structures may be designed to satisfy impedance-mismatch requirements for high performance armor, and possibly provide a multi-hit capability. A demonstration has been made of reactive-HPHT processing of multi-layered composites, consisting of alternating layers of superhard Ti-bonded cBN and tough Ti. It is noteworthy that the pressure requirements for processing Ti-bonded cBN, Ti-bonded TiB2/TiN, and their

  18. Nanostructured diamond-TiC composites with high fracture toughness

    NASA Astrophysics Data System (ADS)

    Wang, Haikuo; He, Duanwei; Xu, Chao; Tang, Mingjun; Li, Yu; Dong, Haini; Meng, Chuanmin; Wang, Zhigang; Zhu, Wenjun

    2013-01-01

    We report the preparation of nanostructured diamond-TiC composites with high fracture toughness and high hardness starting from a ball-milled mixture of nano-sized Ti3SiC2 and submicron-sized diamond by simultaneously tuning the pressure-temperature conditions. The phase segregation of Ti3SiC2 at pressure of 5.5 GPa were investigated by X-ray diffraction and high resolution transmission electron microscopy, we found that the Ti3SiC2 could decompose into nanosized TiC and amorphous Ti-Si at 600-700 °C. The subsequent reaction between diamond and Ti-Si led to an amorphous Ti-Si-C matrix in which diamond and TiC crystals are embedded. With a loading force of 98 N, the measured fracture toughness KIC and Vicker's hardness HV of the synthesized composites reach up to 14 MPa m1/2 and 45.5 GPa, respectively. Our results demonstrate that the nanocrystalline/amorphous bonding matrix could largely enhance the toughness of the brittle composites.

  19. Multilayer Electroactive Polymer Composite Material

    NASA Technical Reports Server (NTRS)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2011-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  20. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1996-01-23

    A high performance capacitor is described which is fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a ``notepad`` configuration composed of 200--300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The ``notepad`` capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density. 5 figs.

  1. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.; O'Brien, Dennis W.

    1995-01-01

    A high performance capacitor fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a "notepad" configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The "notepad" capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density.

  2. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1995-05-09

    A high performance capacitor is fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a ``notepad`` configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The notepad capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density. 5 figs.

  3. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.; O'Brien, Dennis W.

    1996-01-01

    A high performance capacitor fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a "notepad" configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The "notepad" capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density.

  4. Nanostructured photovoltaic materials using conjugated block copolymer assemblies

    NASA Astrophysics Data System (ADS)

    Mastroianni, Sarah E.; Epps, Thomas H., III

    2011-03-01

    Block copolymers containing a conjugated block offer attractive possibilities for creating nanostructured organic photovoltaic (OPV) devices. Current OPV materials suffer from efficiency losses primarily due to a size-scale discrepancy between exciton diffusion length and domain sizes; excitons that do not reach the interface between electron and hole-conducting materials recombine, preventing charge carrier separation. The inherent nature of block-copolymers to self-assemble into well-defined nanoscale structures with domain spacings on the order of exciton diffusion length offers a potential solution for reducing exciton recombination. In this work, allyl-terminated poly(3-hexyl thiophene) or poly(3-decyl thiophene) acting as electron donors are incorporated into the block copolymer chain via a coupling reaction with poly(styrene) or poly(isoprene- b -styrene) derivatives synthesized by anionic polymerization. The resulting block copolymer morphologies are characterized by small angle X-ray scattering and transmission electron microscopy.

  5. Nanophase and Composite Optical Materials

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This talk will focus on accomplishments, current developments, and future directions of our work on composite optical materials for microgravity science and space exploration. This research spans the order parameter from quasi-fractal structures such as sol-gels and other aggregated or porous media, to statistically random cluster media such as metal colloids, to highly ordered materials such as layered media and photonic bandgap materials. The common focus is on flexible materials that can be used to produce composite or artificial materials with superior optical properties that could not be achieved with homogeneous materials. Applications of this work to NASA exploration goals such as terraforming, biosensors, solar sails, solar cells, and vehicle health monitoring, will be discussed.

  6. Materials for Hydrogen Storage: From Complex Hydrides to Functionalized Nanostructures

    NASA Astrophysics Data System (ADS)

    Das, G. P.

    2011-07-01

    The world wide effort for a transition to renewable and clean (i.e. carbon-free) form of energy has resulted in an upsurge of interest in harnessing and utilizing Hydrogen. Apart from being the most abundant element in the universe, hydrogen offers many advantages over other fuels: it is non-toxic, clean to use, and packs more energy per mass than any other fuel. Hydrogen energy production, storage and distribution constitute a multi-disciplinary area of research. Coming to the material issues for solid state storage of hydrogen, the most desirable criteria are high storage capacity, satisfactory kinetics, and optimal thermodynamics. Complex hydrides involving light metals, such as Alanates, Imides, Borates, Amidoboranes etc. show impressive gravimetric efficiencies, although the hydrogen desorption temperatures turn out to be rather high. Apart from complex hydrides, there are other kinds of novel materials that have been investigated, e.g. carbon based materials activated with nano-catalysts, clathrate hydrates, metal-organic complexes, and more recently nanostructured cages viz. fullerenes and nanotubes decorated with simple or transition metals that serve to attract hydrogen in molecular form. In this talk, after giving a broad overview on hydrogen economy, I shall focus on first-principles design of materials for hydrogen storage, from complex hydrides to various kinds of functinalized nanostructures, and discuss the recent results obtained in our laboratory [1-6]. Some outstanding issues and challenges, like how to circumvent the problem of metal clustering on surface, or how to bring down the hydrogen desorption temperature etc. will be discussed.

  7. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves.

    PubMed

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-02-23

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5-20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures.

  8. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves

    NASA Astrophysics Data System (ADS)

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-02-01

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5–20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures.

  9. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves

    PubMed Central

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-01-01

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5–20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures. PMID:26902260

  10. Composite material impregnation unit

    NASA Technical Reports Server (NTRS)

    Wilkinson, S. P.; Marchello, J. M.; Johnston, N. J.

    1993-01-01

    This memorandum presents an introduction to the NASA multi-purpose prepregging unit which is now installed and fully operational at the Langley Research Center in the Polymeric Materials Branch. A description of the various impregnation methods that are available to the prepregger are presented. Machine operating details and protocol are provided for its various modes of operation. These include, where appropriate, the related equations for predicting the desired prepreg specifications. Also, as the prepregger is modular in its construction, each individual section is described and discussed. Safety concerns are an important factor and a chapter has been included that highlights the major safety features. Initial experiences and observations for fiber impregnation are described. These first observations have given great insight into the areas of future work that need to be addressed. Future memorandums will focus on these individual processes and their related problems.

  11. Controlled way to prepare quasi-1D nanostructures with complex chemical composition in porous anodic alumina.

    PubMed

    Lukatskaya, Maria R; Trusov, Lev A; Eliseev, Andrey A; Lukashin, Alexey V; Jansen, Martin; Kazin, Pavel E; Napolskii, Kirill S

    2011-02-28

    Herein we propose a novel approach to the preparation of quasi-1D nanostructures with various chemical compositions based on infiltration of colloidal solution into the asymmetric anodic alumina membrane. The proposed technique was successfully applied for the preparation of ordered arrays of the magnetically hard anisotropic hexaferrite nanostructures.

  12. Tunable nanostructured composite with built-in metallic wire-grid electrode

    SciTech Connect

    Micheli, Davide Pastore, Roberto; Marchetti, Mario; Gradoni, Gabriele

    2013-11-15

    In this paper, the authors report an experimental demonstration of microwave reflection tuning in carbon nanostructure-based composites by means of an external voltage supplied to the material. DC bias voltages are imparted through a metal wire-grid. The magnitude of the reflection coefficient is measured upon oblique plane-wave incidence. Increasing the bias from 13 to 700 V results in a lowering of ∼20 dB, and a “blueshift” of ∼600 MHz of the material absorption resonance. Observed phenomena are ascribed to a change of the dielectric response of the carbon material. Inherently, the physical role of tunneling between nanofillers (carbon nanotubes) is discussed. Achievements aim at the realization of a tunable absorber. There are similar studies in literature that focus on tunable metamaterials operating at either optical or THz wavelengths.

  13. Composite materials for space applications

    NASA Technical Reports Server (NTRS)

    Rawal, Suraj P.; Misra, Mohan S.; Wendt, Robert G.

    1990-01-01

    The objectives of the program were to: generate mechanical, thermal, and physical property test data for as-fabricated advanced materials; design and fabricate an accelerated thermal cycling chamber; and determine the effect of thermal cycling on thermomechanical properties and dimensional stability of composites. In the current program, extensive mechanical and thermophysical property tests of various organic matrix, metal matrix, glass matrix, and carbon-carbon composites were conducted, and a reliable database was constructed for spacecraft material selection. Material property results for the majority of the as-fabricated composites were consistent with the predicted values, providing a measure of consolidation integrity attained during fabrication. To determine the effect of thermal cycling on mechanical properties, microcracking, and thermal expansion behavior, approximately 500 composite specimens were exposed to 10,000 cycles between -150 and +150 F. These specimens were placed in a large (18 cu ft work space) thermal cycling chamber that was specially designed and fabricated to simulate one year low earth orbital (LEO) thermal cycling in 20 days. With this rate of thermal cycling, this is the largest thermal cycling unit in the country. Material property measurements of the thermal cycled organic matrix composite laminate specimens exhibited less than 24 percent decrease in strength, whereas, the remaining materials exhibited less than 8 percent decrease in strength. The thermal expansion response of each of the thermal cycled specimens revealed significant reduction in hysteresis and residual strain, and the average CTE values were close to the predicted values.

  14. EPR and magnetism of the nanostructured natural carbonaceous material shungite

    NASA Astrophysics Data System (ADS)

    Augustyniak-Jabłokow, Maria Aldona; Yablokov, Yurii V.; Andrzejewski, Bartłomiej; Kempiński, Wojciech; Łoś, Szymon; Tadyszak, Krzysztof; Yablokov, Mikhail Y.; Zhikharev, Valentin A.

    2010-04-01

    The X-band EPR and magnetic susceptibility in the temperature range 4.2-300 K study of the shungite-I, natural nanostructured material from the deposit of Shunga are reported. Obtained results allow us to assign the EPR signal to conduction electrons, estimate their number, N P, and evaluate the Pauli paramagnetism contribution to shungite susceptibility. A small occupation (~5%) of the localized nonbonding π states in the zigzag edges of the open-ended graphene-like layers and/or on σ ( sp 2+ x ) orbitals in the curved parts of the shungite globules has been also revealed. The observed temperature dependence of the EPR linewidth can be explained by the earlier considered interaction of conduction π electrons with local phonon modes associated with the vibration of peripheral carbon atoms of the open zigzag-type edges and with peripheral carbon atoms cross-linking different nanostructures. The relaxation time T 2 and diffusion time T D are found to have comparable values (2.84 × 10-8 and 1.73 × 10-8 s at 5.2 K, respectively), and similar dependence on temperature. The magnetic measurements have revealed the suppression of orbital diamagnetism due to small amount of large enough fragments of the graphene layers.

  15. Water-evaporation-induced electricity with nanostructured carbon materials.

    PubMed

    Xue, Guobin; Xu, Ying; Ding, Tianpeng; Li, Jia; Yin, Jun; Fei, Wenwen; Cao, Yuanzhi; Yu, Jin; Yuan, Longyan; Gong, Li; Chen, Jian; Deng, Shaozhi; Zhou, Jun; Guo, Wanlin

    2017-01-30

    Water evaporation is a ubiquitous natural process that harvests thermal energy from the ambient environment. It has previously been utilized in a number of applications including the synthesis of nanostructures and the creation of energy-harvesting devices. Here, we show that water evaporation from the surface of a variety of nanostructured carbon materials can be used to generate electricity. We find that evaporation from centimetre-sized carbon black sheets can reliably generate sustained voltages of up to 1 V under ambient conditions. The interaction between the water molecules and the carbon layers and moreover evaporation-induced water flow within the porous carbon sheets are thought to be key to the voltage generation. This approach to electricity generation is related to the traditional streaming potential, which relies on driving ionic solutions through narrow gaps, and the recently reported method of moving ionic solutions across graphene surfaces, but as it exploits the natural process of evaporation and uses cheap carbon black it could offer advantages in the development of practical devices.

  16. Synthesis and characterization of novel boron-based nanostructures and composites

    NASA Astrophysics Data System (ADS)

    Patel, Rajen B.

    A number of nanomaterials have been synthesized by using a method that has been previously utilized to make pure boron nanostructures through the addition of different reactant gases to the process. This method was pioneered by Iqbal-Liu and will be referred to as the IL method in this dissertation. The IL method successfully created boron nanowires, boron nanoflakes, and boron nanotubes. In this dissertation, by adding methane, hydrogen sulfide, and ammonia to the process, an entire family of nanomaterials is prepared. These include nanowires, nano-heterostructures, and thin nanoplatelets of a variety of elemental compositions. These materials can be integrated with other known nanostructures to form a number of novel electronic nanodevices and nanosensors. A method to create nanocomposites by the chemical vapor infiltration (CVI) of nanomaterials into a metal matrix has been developed further. This work builds on past efforts which successfully developed carbon nanotube (CNT)-infiltrated metal composites which demonstrated enhanced mechanical strength. The nanocomposite method is successfully performed with boron nitride nanotubes in a nano-iron matrix. A graphene composite with iron is also synthesized but, unlike composites with CNTs, there was no strength enhancement. This could be attributed to the two-dimensional morphology of graphene. To put the dissertation in perspective, a review of several characterization techniques utilized is presented, including Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. Additionally, a summary of possible novel growth mechanisms is required to explain the formation mechanism of the materials synthesized in this work. Nearly all of the materials synthesized in this work were grown with a vapor-liquid-growth mechanism. Background information on nanowires, nanotubes, and nanocomposites has also been included to clarify the significance of the research conducted. In conclusion, future

  17. Fiber composite materials technology development

    SciTech Connect

    Chiao, T.T.

    1980-10-23

    The FY1980 technical accomplishments from the Lawrence Livermore National laboratory (LLNL) for the Fiber Composite Materials Technology Development Task fo the MEST project are summarized. The task is divided into three areas: Engineering data base for flywheel design (Washington University will report this part separately), new materials evaluation, and time-dependent behavior of Kevlar composite strands. An epoxy matrix was formulated which can be used in composites for 120/sup 0/C service with good processing and mechanical properties. Preliminary results on the time-dependent properties of the Kevlar 49/epoxy strands indicate: Fatigue loading, as compared to sustained loading, drastically reduces the lifetime of a Kevlar composie; the more the number of on-off load cycles, the less the lifetime; and dynamic fatigue of the Kevlar composite can not be predicted by current damage theories such as Miner's Rule.

  18. Synthesis of 3D nanostructured metal alloy of immiscible materials induced by megahertz-repetition femtosecond laser pulses

    PubMed Central

    2012-01-01

    In this work, we have proposed a concept for the generation of three-dimensional (3D) nanostructured metal alloys of immiscible materials induced by megahertz-frequency ultrafast laser pulses. A mixture of two microparticle materials (aluminum and nickel oxide) and nickel oxide microparticles coated onto an aluminum foil have been used in this study. After laser irradiation, three different types of nanostructure composites have been observed: aluminum embedded in nickel nuclei, agglomerated chain of aluminum and nickel nanoparticles, and finally, aluminum nanoparticles grown on nickel microparticles. In comparison with current nanofabrication methods which are used only for one-dimensional nanofabrication, this technique enables us to fabricate 3D nanostructured metal alloys of two or more nanoparticle materials with varied composite concentrations under various predetermined conditions. This technique can lead to promising solutions for the fabrication of 3D nanostructured metal alloys in applications such as fuel-cell energy generation and development of custom-designed, functionally graded biomaterials and biocomposites. PMID:22999219

  19. Composite Materials for Maxillofacial Prostheses.

    DTIC Science & Technology

    1982-11-01

    1(AXILLOFACIAL PROSTHESES; PROSTHETIC MATERIALS: MICROCAPSULES : SOFT FILLERS; ELASTOMER COMPOSITES *ASTRAC7 lCofIflU Ir F*vsda Side It neceOaeen anud...composite systems are elastomeric-shelled, liquid-filled microcapsules . Experiments continued on the interfacial polymerization process, with spherical...sealed, capsules achieved. The diamine bath has been E] improved and an automatic system has been developed for producing the microcapsules . The one

  20. Fatigue Damage in Composite Materials

    NASA Astrophysics Data System (ADS)

    Revuelta, D.; Miravete, A.

    2002-02-01

    The phenomenon of fatigue is critical for designing structures including elements made of composite materials. The accurate prediction of the life and fatigue resistance of laminated composites is one of the subjects of inquiry in materials science. The ability of predicting the life of laminates is important for designing, operation, and safety analysis of a composite structure under specific conditions. To predict reliably the life of structures, it is necessary to know the mechanisms of cyclic deformation and damage. It is also necessary to develop a qualitative theory of fatigue failure that should be based on the concepts of solids mechanics. Developing such a theory requires to evaluate the microscopic parameters and the macroscopic variables of the material at the level of a laminate and the structure and to determine exactly the load modes acting on the system.

  1. Nano-structured electron transporting materials for perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Liu, Hefei; Huang, Ziru; Wei, Shiyuan; Zheng, Lingling; Xiao, Lixin; Gong, Qihuang

    2016-03-01

    Organic-inorganic hybrid perovskite solar cells have been developing rapidly in the past several years, and their power conversion efficiency has reached over 20%, nearing that of polycrystalline silicon solar cells. Because the diffusion length of the hole in perovskites is longer than that of the electron, the performance of the device can be improved by using an electron transporting layer, e.g., TiO2, ZnO and TiO2/Al2O3. Nano-structured electron transporting materials facilitate not only electron collection but also morphology control of the perovskites. The properties, morphology and preparation methods of perovskites are reviewed in the present article. A comprehensive understanding of the relationship between the structure and property will benefit the precise control of the electron transporting process and thus further improve the performance of perovskite solar cells.

  2. Nano-structured electron transporting materials for perovskite solar cells.

    PubMed

    Liu, Hefei; Huang, Ziru; Wei, Shiyuan; Zheng, Lingling; Xiao, Lixin; Gong, Qihuang

    2016-03-28

    Organic-inorganic hybrid perovskite solar cells have been developing rapidly in the past several years, and their power conversion efficiency has reached over 20%, nearing that of polycrystalline silicon solar cells. Because the diffusion length of the hole in perovskites is longer than that of the electron, the performance of the device can be improved by using an electron transporting layer, e.g., TiO2, ZnO and TiO2/Al2O3. Nano-structured electron transporting materials facilitate not only electron collection but also morphology control of the perovskites. The properties, morphology and preparation methods of perovskites are reviewed in the present article. A comprehensive understanding of the relationship between the structure and property will benefit the precise control of the electron transporting process and thus further improve the performance of perovskite solar cells.

  3. Multifunctional, flexible electronic systems based on engineered nanostructured materials

    NASA Astrophysics Data System (ADS)

    Ko, Hyunhyub; Kapadia, Rehan; Takei, Kuniharu; Takahashi, Toshitake; Zhang, Xiaobo; Javey, Ali

    2012-08-01

    The development of flexible electronic systems has been extensively researched in recent years, with the goal of expanding the potential scope and market of modern electronic devices in the areas of computation, communications, displays, sensing and energy. Uniquely, the use of soft polymeric substrates enables the incorporation of advanced features beyond mechanical bendability and stretchability. In this paper, we describe several functionalities which can be achieved using engineered nanostructured materials. In particular, reversible binding, self-cleaning, antireflective and shape-reconfigurable properties are introduced for the realization of multifunctional, flexible electronic devices. Examples of flexible systems capable of spatial mapping and/or responding to external stimuli are also presented as a new class of user-interactive devices.

  4. Repeatable Hydrogen Storage using Nano-structured Graphite Materials

    NASA Astrophysics Data System (ADS)

    Kajiura, Hisashi; Kadono, Koji; Tsutsui, Shigemitsu; Murakami, Yousuke

    2004-03-01

    Repeatable hydrogen adsorption and desorption with nano-structured graphite material (NSG) was confirmed using a high-accuracy volumetric measuring apparatus at room temperature [1]. The NSG was prepared from commercially obtained graphite powder with a purity of 99.997% (GoodFellow Cambridge Ltd.) using a mechanical milling process at a pressure of 2.0 x 10-4 Pa. The untreated graphite adsorbed 0.02wt% of hydrogen, while 0.20 - 0.25wt% of hydrogen can be repeatedly adsorbed by the NSG. Measurements of the hydrogen adsorption rate at constant pressure and pore-size distribution suggest that the hydrogen molecules are adsorbed through a diffusion process into pores with a diameter less than 1 nm. [1] H.Kajiura et al., APL82(2003)1929.

  5. Necklace-like NiO-CuO Heterogeneous Composite Hollow Nanostructure: Preparation, Formation Mechanism and Structure Control.

    PubMed

    Xu, Shao Hui; Fei, Guang Tao; Ouyang, Hao Miao; Shang, Guo Liang; Gao, Xu Dong; Zhang, Li De

    2017-12-01

    Composite hollow nanostructure composed by transition metal oxides are promising materials in electrochemistry, catalyst chemistry and material science. In this contribution, necklace-like NiO-CuO heterogeneous composite hollow nanostructures were synthesized by annealing Ni/Cu superlattice nanowires in air. Two kinds of morphologies including CuO nanotube linked core-shell structures and CuO nanotube linked hollow structures were obtained. The structure can be tuned easily by adjusting the relative length of Cu segments in Ni/Cu superlattice nanowires and the annealing temperature. The relative diffusion amount of Cu to Ni segments was proved to be the key factor to influence the annealed sample morphology. The formation mechanism was discussed in detail based on Kirkendal effect and high temperature oxidation of alloy. We demonstrated that hollow structure or core-shell structure is related to whether the oxidation exists only in external sites or co-exists in external and internal sites during annealing.

  6. The synthesis of rutile nano-structured TiO2 composite under low temperature

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Zheng, Yibo; Dong, Mofei; Li, Simian

    2012-11-01

    In this paper, in order to improve the photocatalytic application of TiO2, the low-density material such as Ps and TiCl4 is proposed to be the raw carrier, and the nana-structured TiO2 composite is obtained by combining the sol-gel technology and layer-by-layer self-assembly methods; The pure rutile nano-structured TiO2 whose diameter is about 0.25mm are prepared under different conditions at low temperature. By being calcined under 450 ℃ the hollow sphere TiO2 is prepared and its composition, size, structure analysis and characterization are studied by using X ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal gravimetric analysis (DSC-TG) respectively.

  7. Graphene-Elastomer Composites with Segregated Nanostructured Network for Liquid and Strain Sensing Application.

    PubMed

    Lin, Yong; Dong, Xuchu; Liu, Shuqi; Chen, Song; Wei, Yong; Liu, Lan

    2016-09-14

    One of the critical issues for the fabrication of desirable sensing materials has focused on the construction of an effective continuous network with a low percolation threshold. Herein, graphene-based elastomer composites with a segregated nanostructured graphene network were prepared by a novel and effective ice-templating strategy. The segregated graphene network bestowed on the natural rubber (NR) composites an ultralow electrical percolation threshold (0.4 vol %), 8-fold lower than that of the NR/graphene composites with homogeneous dispersion morphology (3.6 vol %). The resulting composites containing 0.63 vol % graphene exhibited high liquid sensing responsivity (6700), low response time (114 s), and good reproducibility. The unique segregated structure also provides this graphene-based elastomer (containing 0.42 vol % graphene) with exceptionally high stretchability, sensitivity (gauge factor ≈ 139), and good reproducibility (∼400 cycles) of up to 60% strain under cyclic tests. The fascinating performances highlight the potential applications of graphene-elastomer composites with an effective segregated network as multifunctional sensing materials.

  8. Nanostructured lithium sulfide materials for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Kyu; Lee, Yun Jung; Sun, Yang-Kook

    2016-08-01

    Upon the maturation and saturation of Li-ion battery technologies, the demand for the development of energy storage systems with higher energy densities has surged to meet the needs of key markets such as electric vehicles. Among the many next generation high-energy storage options, the Lisbnd S battery system is considered particularly close to mass commercialization because of its low cost and the natural abundance of sulfur. In this review, we focus on nanostructured Li2S materials for Lisbnd S batteries. Due to a lithium source in its molecular structure, Li2S can be coupled with various Li-free anode materials, thereby giving it the potential to surmount many of the problems related with a Li-metal anode. The hurdles that impede the full utilization of Li2S materials include its high activation barrier and the low electrical conductivity of bulk Li2S particles. Various strategies that can be used to assist the activation process and facilitate electrical transport are analyzed. To provide insight into the opportunities specific to Li2S materials, we highlight some major advances and results that have been achieved in the development of metal Li-free full cells and all-solid-state cells based on Li2S cathodes.

  9. Delamination growth in composite materials

    NASA Technical Reports Server (NTRS)

    Gillespie, J. W., Jr.; Carlson, L. A.; Pipes, R. B.; Rothschilds, R.; Trethewey, B.; Smiley, A.

    1985-01-01

    Research related to growth of an imbedded through-width delamination (ITWD) in a compression loaded composite structural element is presented. Composites with widely different interlaminar fracture resistance were examined, viz., graphite/epoxy (CYCOM 982) and graphite/PEEK (APC-2). The initial part of the program consisted of characterizing the material in tension, compression and shear mainly to obtain consistent material properties for analysis, but also as a check of the processing method developed for the thermoplastic APC-2 material. The characterization of the delamination growth in the ITWD specimen, which for the unidirectional case is essentially a mixed Mode 1 and 2 geometry, requires verified mixed-mode growth criteria for the two materials involved. For this purpose the main emphasis during this part of the investigation was on Mode 1 and 2 fracture specimens, namely the Double Cantilever Beam (DCB) and End Notched Flexure (ENF) specimens.

  10. Bioinspired Composite Materials: Applications in Diagnostics and Therapeutics

    NASA Astrophysics Data System (ADS)

    Prasad, Alisha; Mahato, Kuldeep; Chandra, Pranjal; Srivastava, Ananya; Joshi, Shrikrishna N.; Maurya, Pawan Kumar

    2016-08-01

    Evolution-optimized specimens from nature with inimitable properties, and unique structure-function relationships have long served as a source of inspiration for researchers all over the world. For instance, the micro/nanostructured patterns of lotus-leaf and gecko feet helps in self-cleaning, and adhesion, respectively. Such unique properties shown by creatures are results of billions of years of adaptive transformation, that have been mimicked by applying both science and engineering concepts to design bioinspired materials. Various bioinspired composite materials have been developed based on biomimetic principles. This review presents the latest developments in bioinspired materials under various categories with emphasis on diagnostic and therapeutic applications.

  11. Cellular Composites with Ambient and Autoclaved Type of Hardening with Application of Nanostructured Binder

    NASA Astrophysics Data System (ADS)

    Nelyubova, V.; Pavlenko, N.; Netsvet, D.

    2015-11-01

    The research presents the dimensional and structural characteristics of nonhydrational hardening binders - nanostructured binders. Rational areas of their use in composites for construction purposes are given. The paper presents the results of the development of natural hardening foam concrete and aerated autoclaved concrete for thermal insulating and construction and thermal insulating purposes. Thus nanostructured binder (NB) in the composites was used as a primary binder and a high reactive modifier.

  12. Three-dimensional composite metallodielectric nanostructure for enhanced surface plasmon resonance sensing

    NASA Astrophysics Data System (ADS)

    Chen, Haiping Matthew; Pang, Lin; Kher, Aditya; Fainman, Yeshaiahu

    2009-02-01

    The authors simulated, fabricated, and characterized a mushroomlike composite metallodielectric nanostructure that shows improved characteristics for surface plasmon resonance sensing applications with an enhancement in the normal electric field compared to the conventional nanohole structure. A fabrication method is introduced to give controllable linewidth by an oblique metal deposition process. A sensor built with the composite nanostructure was then used to determine the hydrophilicity of its surface by monitoring the resonant wavelength shift and computing the corresponding adsorption thickness.

  13. Composite Materials: An Educational Need.

    ERIC Educational Resources Information Center

    Saliba, Tony E.; Snide, James A.

    1990-01-01

    Described is the need to incorporate the concepts and applications of advanced composite materials into existing chemical engineering programs. Discussed are the justification for, and implementation of topics including transport phenomena, kinetics and reactor design, unit operations, and product and process design. (CW)

  14. Composite Materials for Maxillofacial Prostheses.

    DTIC Science & Technology

    1981-08-01

    necessary and Identify byv block number) MAXILLOFACIAL PROSTHESES; PROSTHETIC MATERIALS: MICROCAPSULES : SOFT FILLERS; ELASTOMER COMPOSITES 2,. ABSTRACT...used as fillers in the fabrication of maxillofacial prostheses. The projected systems are elastomeric-shelled, liquid-filled microcapsules . Improvements...elastomeric-shelled, liquid-filled microcapsules . Experiments continued on the interfacial polymerization process, with spherical, sealed, capsules

  15. Composite Materials for Maxillofacial Prostheses.

    DTIC Science & Technology

    1983-02-01

    the most promise for producing elastomeric-shelled microcapsules containing an inert liquid. While much of the diverse field of microencapsulation is...Processes and Applications, Chicago, 28 August 1973. 11. Gutchko, M. H., Microcapsules and Microencapsulation Techniques. Noyes Data Corporation, Park Ridge...necesaryv and identify by block number) * MAXILLOFACIAL PROSTHESES; PROSTHETIC MATERIALS: MICROCAPSULES : * SOFT FILLERS; ELASTOMER COMPOSITES 2L

  16. Joining of polymer composite materials

    SciTech Connect

    Magness, F.H.

    1990-11-01

    Under ideal conditions load bearing structures would be designed without joints, thus eliminating a source of added weight, complexity and weakness. In reality the need for accessibility, repair, and inspectability, added to the size limitations imposed by the manufacturing process and transportation/assembly requirements mean that some minimum number of joints will be required in most structures. The designer generally has two methods for joining fiber composite materials, adhesive bonding and mechanical fastening. As the use of thermoplastic materials increases, a third joining technique -- welding -- will become more common. It is the purpose of this document to provide a review of the available sources pertinent to the design of joints in fiber composites. The primary emphasis is given to adhesive bonding and mechanical fastening with information coming from documentary sources as old as 1961 and as recent as 1989. A third, shorter section on composite welding is included in order to provide a relatively comprehensive treatment of the subject.

  17. Nanostructure control of graphene-composited TiO2 by a one-step solvothermal approach for high performance dye-sensitized solar cells.

    PubMed

    He, Ziming; Guai, Guanhong; Liu, Jing; Guo, Chunxian; Loo, Joachim Say Chye; Li, Chang Ming; Tan, Timothy Thatt Yang

    2011-11-01

    We present a one-step solvothermal approach to prepare uniform graphene-TiO(2) nanocomposites with delicately controlled TiO(2) nanostructures, including ultra-small 2 nm nanoparticles, 12 nm nanoparticles and nanorods. Using three composites as photoanode materials, the effect of nanostructure of graphene-composited TiO(2) on the performance of dye-sensitized solar cells was investigated, and results showed that the ultra-small 2 nm TiO(2)-graphene composite based photoanode exhibited the highest power conversion efficiency of 7.25%.

  18. Nanostructured metal oxide-based materials as advanced anodes for lithium-ion batteries.

    PubMed

    Wu, Hao Bin; Chen, Jun Song; Hng, Huey Hoon; Lou, Xiong Wen David

    2012-04-21

    The search for new electrode materials for lithium-ion batteries (LIBs) has been an important way to satisfy the ever-growing demands for better performance with higher energy/power densities, improved safety and longer cycle life. Nanostructured metal oxides exhibit good electrochemical properties, and they are regarded as promising anode materials for high-performance LIBs. In this feature article, we will focus on three different categories of metal oxides with distinct lithium storage mechanisms: tin dioxide (SnO(2)), which utilizes alloying/dealloying processes to reversibly store/release lithium ions during charge/discharge; titanium dioxide (TiO(2)), where lithium ions are inserted/deinserted into/out of the TiO(2) crystal framework; and transition metal oxides including iron oxide and cobalt oxide, which react with lithium ions via an unusual conversion reaction. For all three systems, we will emphasize that creating nanomaterials with unique structures could effectively improve the lithium storage properties of these metal oxides. We will also highlight that the lithium storage capability can be further enhanced through designing advanced nanocomposite materials containing metal oxides and other carbonaceous supports. By providing such a rather systematic survey, we aim to stress the importance of proper nanostructuring and advanced compositing that would result in improved physicochemical properties of metal oxides, thus making them promising negative electrodes for next-generation LIBs.

  19. Modeling of nanostructured porous thermoelastic composites with surface effects

    NASA Astrophysics Data System (ADS)

    Nasedkin, A. V.; Nasedkina, A. A.; Kornievsky, A. S.

    2017-01-01

    The paper presents an integrated approach for determination of effective properties of anisotropic porous thermoelastic materials with a nanoscale stochastic porosity structure. This approach includes the effective moduli method for composite me-chanics, the simulation of representative volumes and the finite element method. In order to take into account nanoscale sizes of pores, the Gurtin-Murdoch model of surface stresses and the highly conducting interface model are used at the borders between material and pores. The general methodology for determination of effective properties of porous composites is demonstrated for a two-phase composite with special conditions for stresses and heat flux discontinuities at the phase interfaces. The mathematical statements of boundary value problems and the resulting formulas to determine the complete set of effective constants of the two-phase composites with arbitrary anisotropy and with surface properties are described; the generalized statements are formulated and the finite element approximations are given. It is shown that the homogenization procedures for porous composites with surface effects can be considered as special cases of the corresponding procedures for the two-phase composites with interphase stresses and heat fluxes if the moduli of nanoinclusions are negligibly small. These approaches have been implemented in the finite element package ANSYS for a model of porous material with cubic crystal system for various values of surface moduli, porosity and number of pores. It has been noted that the magnitude of the area of the interphase boundaries has influence on the effective moduli of the porous materials with nanosized structure.

  20. Nanostructured nickel-free austenitic stainless steel/hydroxyapatite composites.

    PubMed

    Tulinski, Maciej; Jurczyk, Mieczyslaw

    2012-11-01

    In this work Ni-free austenitic stainless steels with nanostructure and their nanocomposites with hydroxyapatite are presented and characterized by means of X-ray diffraction and optical profiling. The samples were synthesized by mechanical alloying, heat treatment and nitriding of elemental microcrystalline powders with addition of hydroxyapatite (HA). In our work we wanted to introduce into stainless steel hydroxyapatite ceramics that have been intensively studied for bone repair and replacement applications. Such applications were chosen because of their high biocompatibility and ability to bond to bone. Since nickel-free austenitic stainless steels seem to have better mechanical properties, corrosion resistance and biocompatibility compared to 316L stainless steels, it is possible that composite made of this steel and HA could improve properties, as well. Mechanical alloying and nitriding are very effective technologies to improve the corrosion resistance of stainless steel. Similar process in case of nanocomposites of stainless steel with hydroxyapatite helps achieve even better mechanical properties and corrosion resistance. Hence nanocrystalline nickel-free stainless steels and nickel-free stainless steel/hydroxyapatite nanocomposites could be promising bionanomaterials for use as a hard tissue replacement implants, e.g., orthopedic implants. In such application, the surface roughness and more specifically the surface topography influences the proliferation of cells (e.g., osteoblasts).

  1. Development of nanostructured biocompatible materials for chemical and biological sensors

    NASA Astrophysics Data System (ADS)

    Curley, Michael; Chilvery, Ashwith K.; Kukhatreva, Tatiana; Sharma, Anup; Corda, John; Farley, Carlton

    2012-10-01

    This research is focused on the fabrication of thin films followed by Surface Enhanced Raman Spectroscopy (SERS) testing of these films for various applications. One technique involves the mixture of nanoparticles with twophoton material to be used as an indicator dye. Another method involved embedding silver nanoparticles in a ceramic nano-membrane. The substrates were characterized by both Atom Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). We applied the nanostructured substrate to measure the SERS spectra of 10-6 Mol/L Rhodomine 6G(Rh6G), e-coli bacteria and RDX explosive. Our results showed that silver coated ceramic membranes can serve as appropriate substrates to enhance Raman signals. In addition, we demonstrated that the in-house-made colloidal silver can work for enhancement of the Raman spectra for bacteria. We measured the Raman spectra of Rh6G molecules on a substrate absorbed by a nanofluid of silver. We observed several strong Raman bands - 613cm-1,768 cm-1,1308cm-1 1356 cm-1,1510cm-1, which correspond to Rh6G vibrational modes υ53,υ65,υ115,υ117,υ146 respectively, using a ceramic membrane coated by silver. The Raman spectra of Rh6G absorbed by silver nanofluid showed strong enhancement of Raman bands 1175cm-1 and 1529cm-1, 1590 cm-1. Those correspond to vibrational frequency modes - υ103,υ151,152. We also measured the Raman spectra of e-coli bacteria, both absorbed by silver nanofluid, and on nanostructured substrate. In addition, the Fourier Transfer Infrared Spectra (FTIR) of the bacteria was measured.

  2. Energy absorption of composite materials

    NASA Technical Reports Server (NTRS)

    Farley, G. L.

    1983-01-01

    Results of a study on the energy absorption characteristics of selected composite material systems are presented and the results compared with aluminum. Composite compression tube specimens were fabricated with both tape and woven fabric prepreg using graphite/epoxy (Gr/E), Kevlar (TM)/epoxy (K/E) and glass/epoxy (Gl/E). Chamfering and notching one end of the composite tube specimen reduced the peak load at initial failure without altering the sustained crushing load, and prevented catastrophic failure. Static compression and vertical impact tests were performed on 128 tubes. The results varied significantly as a function of material type and ply orientation. In general, the Gr/E tubes absorbed more energy than the Gl/E or K/E tubes for the same ply orientation. The 0/ + or - 15 Gr/E tubes absorbed more energy than the aluminum tubes. Gr/E and Gl/E tubes failed in a brittle mode and had negligible post crushing integrity, whereas the K/E tubes failed in an accordian buckling mode similar to the aluminum tubes. The energy absorption and post crushing integrity of hybrid composite tubes were not significantly better than that of the single material tubes.

  3. Nanostructured electrode materials for Li-ion battery

    NASA Astrophysics Data System (ADS)

    Balaya, Palani; Saravanan, Kuppan; Hariharan, Srirama

    2010-04-01

    Nanostructured materials have triggered a great excitement in recent times due to both fundamental interest as well as technological impact relevant for lithium ion batteries (LIBs). Size reduction in nanocrystals leads to a variety of unexpected exciting phenomena due to enhanced surface-to-volume ratio and reduced transport length. We will consider a few examples of nanostructured electrode materials in the context of lithium batteries for achieving high storage and high rate performances: 1) LiFePO4 nanoplates synthesized using solvothermal method could store Li-ions comparable to its theoretical capacity at C/10, while at 30C, they exhibit storage capacity up to 45 mAh/g. Size reduction (~30 nm) at the b-axis favors the fast Li-ion diffusion. In addition to this, uniform ~5 nm carbon coating throughout the plates provides excellent electronically conducting path for electrons. This nano architecture enables fast insertion/extraction of both Li-ions as well as electrons; 2) Mesporous-TiO2 with high surface area (135m2/g) synthesized using soft-template method exhibits high volumetric density compared to commercial nanopowder (P25), with excellent Li-storage behavior. C16 meso-TiO2 synthesized from CTAB exhibits reversible storage capacity of 288mAh/g at 0.2C and 109 mAh/g at 30C; 3) Zero strain Li4Ti5O12 anode material has been synthesized using several wet chemical routes. The best condition has been optimized to achieve storage capability close to theoretical limit of 175mAh/g at C/10. At 10C, we could retain lithium storage up to 88 mAh/g; 4) We report our recent results on α-Fe2O3 and γ-Fe2O3 using conversion reaction, providing insight for a better storage capability in γ-phase than the α-phase at 2C resulting solely from the nanocrystallinity.

  4. Nanostructured materials with biomimetic recognition abilities for chemical sensing

    NASA Astrophysics Data System (ADS)

    Bajwa, Sadia Zafar; Mustafa, Ghulam; Samardzic, Renata; Wangchareansak, Thipvaree; Lieberzeit, Peter A.

    2012-06-01

    Binding features found in biological systems can be implemented into man-made materials to design nanostructured artificial receptor matrices which are suitable, e.g., for chemical sensing applications. A range of different non-covalent interactions can be utilized based on the chemical properties of the respective analyte. One example is the formation of coordinative bonds between a polymerizable ligand (e.g., N-vinyl-2-pyrrolidone) and a metal ion (e.g., Cu(II)). Optimized molecularly imprinted sensor layers lead to selectivity factors of at least 2 compared to other bivalent ions. In the same way, H-bonds can be utilized for such sensing purposes, as shown in the case of Escherichia coli. The respective molecularly imprinted polymer leads to the selectivity factor of more than 5 between the W and B strains, respectively. Furthermore, nanoparticles with optimized Pearson hardness allow for designing sensors to detect organic thiols in air. The `harder' MoS2 yields only about 40% of the signals towards octane thiol as compared to the `softer' Cu2S. However, both materials strongly prefer molecules with -SH functionality over others, such as hydrocarbon chains. Finally, selectivity studies with wheat germ agglutinin (WGA) reveal that artificial receptors yield selectivities between WGA and bovine serum albumin that are only about a factor of 2 which is smaller than natural ligands.

  5. Precursor Derived Nanostructured Si-C-X Materials for Nuclear Applications. Final Report, October 2010 - September 2014

    SciTech Connect

    Bordia, Rajendra; Tomar, Vikas; Henager, Chuck

    2015-04-08

    Polymer derived ceramic route is an attractive approach to make structural materials with unique nanostructures that have very desirable high temperature properties. Processing techniques to make a variety of needed shapes and forms (e.g. coatings, matrices for fiber reinforced composites, porous ceramics) have been developed. With appropriate high temperature processing, the precursors can be converted to nano-crystalline materials. In this collaborative project, we investigated the processing, stability and properties of nanostructured Si-C materials, derived from polymeric precursors, and their performance under conditions appropriate for nuclear energy applications. All the milestones of the project were accomplished. Some of the results are being currently analyzed and additional papers being prepared in which support from NEUP will be acknowledged. So far, eight peer-reviewed papers have been published and one invention disclosure made. In this report, we summarize the major findings of this project.

  6. Carbon fiber CVD coating by carbon nanostructured for space materials protection against atomic oxygen

    NASA Astrophysics Data System (ADS)

    Pastore, Roberto; Bueno Morles, Ramon; Micheli, Davide

    2016-07-01

    adhesion and durability in the environment. Though these coatings are efficient in protecting polymer composites, their application imposes severe constraints. Their thermal expansion coefficients may differ markedly from those of polymer composite substrates: as a result, cracks develop in the coatings on thermal cycling and AO can penetrate through them to the substrate. In addition to the technicalities of forming an effective barrier, such factors as cost, convenience of application and ease of repair are important considerations in the selection of a coating for a particular application. The latter issues drive the aerospace research toward the development of novel light composite materials, like the so called polymer nanocomposites, which are materials with a polymer matrix and a filler with at least one dimension less than 100 nanometers. Current interest in nanocomposites has been generated and maintained because nanoparticle-filled polymers exhibit unique combinations of properties not achievable with traditional composites. These combinations of properties can be achieved because of the small size of the fillers, the large surface area the fillers provide, and in many cases the unique properties of the fillers themselves. In particular, the carbon fiber-based polymeric composite materials are the basic point of interest: the aim of the present study is to find new solution to produce carbon fiber-based composites with even more upgraded performances. One intriguing strategy to tackle such an issue has been picked out in the coupling between the carbon fibers and the carbon nanostructures. That for two main reasons: first, carbon nanostructures have shown fancy potentialities for any kind of technological applications since their discovery, second, the chemical affinity between fiber and nanostructure (made of the same element) should be a likely route to approach the typical problems due to thermo-mechanical compatibility. This work is joined in such framework

  7. Survey of materials for nanoskiving and influence of the cutting process on the nanostructures produced.

    PubMed

    Lipomi, Darren J; Martinez, Ramses V; Rioux, Robert M; Cademartiri, Ludovico; Reus, William F; Whitesides, George M

    2010-09-01

    This paper examines the factors that influence the quality of nanostructures fabricated by sectioning thin films with an ultramicrotome ("nanoskiving"). It surveys different materials (metals, ceramics, semiconductors, and conjugated polymers), deposition techniques (evaporation, sputter deposition, electroless deposition, chemical-vapor deposition, solution-phase synthesis, and spin-coating), and geometries (nanowires or two-dimensional arrays of rings and crescents). It then correlates the extent of fragmentation of the nanostructures with the composition of the thin films, the methods used to deposit them, and the parameters used for sectioning. There are four major conclusions. (i) Films of soft and compliant metals (those that have bulk values of hardness less than or equal to those of palladium, or ≤500 MPa) tend to remain intact upon sectioning, whereas hard and stiff metals (those that have values of hardness greater than or equal to those of platinum, or ≥500 MPa) tend to fragment. (ii) All conjugated polymers tested form intact nanostructures. (iii) The extent of fragmentation is lowest when the direction of cutting is perpendicular to the exposed edge of the embedded film. (iv) The speed of cutting-from 0.1 to 8 mm/s-has no effect on the frequency of defects. Defects generated during sectioning include scoring from defects in the knife, delamination of the film from the matrix, and compression of the matrix. The materials tested were: aluminum, titanium, nickel, copper, palladium, silver, platinum, gold, lead, bismuth, germanium, silicon dioxide (SiO2), alumina (Al2O3), tin-doped indium oxide (ITO), lead sulfide nanocrystals, the semiconducting polymers poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV), poly(3-hexylthiophene) (P3HT), and poly(benzimidazobenzophenanthroline ladder) (BBL), and the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS).

  8. Electrical and thermal transport measurements on nano-structured materials

    NASA Astrophysics Data System (ADS)

    Chang, Chih-Wei

    This thesis discusses electrical and thermal transport measurements on C60, carbon nanotubes, and boron-nitride nanotubes. Chapter 1 describes the anomalous resistivity behavior of Ag films on C60 crystals. The correlation of the resistivity anomaly and the structural phase transition is established. Chapter 2 gives an introduction to the physical properties and the synthesis methods of carbon and boron nitride nanotubes. Chapter 3 shows two different approaches on chemical functionalization of boron-nitride nanotubes. Chapter 4 gives the theoretical background of thermal conductivity, especially for nano-structured materials. A summary of theoretical and experimental works on the thermal conductivity of nanotubes is given. Chapter 5 discusses the experimental results of thermal conductivity of nanotube mats. An absolute value of the thermal conductivity of boron nitride nanotubes is bracketed and can be compared to the results of the following chapters on individual nanotubes. Chapter 6 describes the experimental methods of measuring thermal conductivity of individual nanotubes. Chapter 7 shows the 2 temperature dependent thermal conductivity and thermopower of individual nanotubes. Chapter 8 discusses the isotope effect and the diameter dependence of the thermal conductivity of nanotubes. In chapter 9, it is shown that the thermal conductivity of nanotubes is robust against electron irradiation and structural deformation. Importantly, the observation challenges current understandings on the thermal transport of nano-structured materials. In chapter 10, it is shown that it is possible to reversibly tune the thermal conductivity of a multiwalled nanotube by controllably sliding the outer-shells against inner cores. Chapter 11 describes a thermal rectifier by engineering the mass distribution along a nanotube. The observed non-zero thermal rectification effect provides strong evidence for solitons in nanotubes. The soliton model also coherently explains many

  9. Composite WO3/TiO2 nanostructures for high electrochromic activity.

    SciTech Connect

    Reyes, Karla Rosa; Stephens, Zachary Dan.; Robinson, David B.

    2013-05-01

    A composite material consisting of TiO2 nanotubes (NTs) with WO3 electrodeposited homogeneously on its surface has been fabricated, detached from its substrate, and attached to a fluorine-doped tin oxide film on glass for application to electrochromic (EC) reactions. A paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length on the current density and the EC contrast of the material were studied. The EC redox reaction seen in this material is diffusion- limited, having relatively fast reaction rates at the electrode surface. The composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast and longer memory time compared with the pure WO3 and TiO2.

  10. Asymmetric Dielectric Elastomer Composite Material

    NASA Technical Reports Server (NTRS)

    Stewart, Brian K. (Inventor)

    2014-01-01

    Embodiments of the invention provide a dielectric elastomer composite material comprising a plurality of elastomer-coated electrodes arranged in an assembly. Embodiments of the invention provide improved force output over prior DEs by producing thinner spacing between electrode surfaces. This is accomplished by coating electrodes directly with uncured elastomer in liquid form and then assembling a finished component (which may be termed an actuator) from coated electrode components.

  11. Ionic self-assembly for functional hierarchical nanostructured materials.

    PubMed

    Faul, Charl F J

    2014-12-16

    CONSPECTUS: The challenge of constructing soft functional materials over multiple length scales can be addressed by a number of different routes based on the principles of self-assembly, with the judicious use of various noncovalent interactions providing the tools to control such self-assembly processes. It is within the context of this challenge that we have extensively explored the use of an important approach for materials construction over the past decade: exploiting electrostatic interactions in our ionic self-assembly (ISA) method. In this approach, cooperative assembly of carefully chosen charged surfactants and oppositely charged building blocks (or tectons) provides a facile noncovalent route for the rational design and production of functional nanostructured materials. Generally, our research efforts have developed with an initial focus on establishing rules for the construction of novel noncovalent liquid-crystalline (LC) materials. We found that the use of double-tailed surfactant species (especially branched double-tailed surfactants) led to the facile formation of thermotropic (and, in certain cases, lyotropic) phases, as demonstrated by extensive temperature-dependent X-ray and light microscopy investigations. From this core area of activity, research expanded to cover issues beyond simple construction of anisotropic materials, turning to the challenge of inclusion and exploitation of switchable functionality. The use of photoactive azobenzene-containing ISA materials afforded opportunities to exploit both photo-orientation and surface relief grating formation. The preparation of these anisotropic LC materials was of interest, as the aim was the facile production of disposable and low-cost optical components for display applications and data storage. However, the prohibitive cost of the photo-orientation processes hampered further exploitation of these materials. We also expanded our activities to explore ISA of biologically relevant tectons

  12. New Composite Thermoelectric Materials for Macro-size Applications

    ScienceCinema

    Dresselhaus, Mildred [MIT, Cambridge, Massachusetts, United States

    2016-07-12

    A review will be given of several important recent advances in both thermoelectrics research and industrial thermoelectric applications, which have attracted much attention, increasing incentives for developing advanced materials appropriate for large-scale applications of thermoelectric devices. One promising strategy is the development of materials with a dense packing of random nanostructures as a route for the sacle-up of thermoelectrics applications. The concepts involved in designing composite materials containing nanostructures for thermoelectric applications will be discussed in general terms. Specific application is made to the Bi{sub 2}Te{sub 3} nanocomposite system for use in power generation. Also emphasized are the scientific advantages of the nanocomposite approach for the simultaneous increase in the power factor and decrease of the thermal conductivity, along with the practical advantages of having bulk samples for property measurements and device applications. A straightforward path is identified for the scale-up of thermoelectric materials synthesis containing nanostructured constituents for use in thermoelectric applications. We end with some vision of where the field of thermoelectrics is now heading.

  13. New Composite Thermoelectric Materials for Macro-size Applications

    SciTech Connect

    Dresselhaus, Mildred

    2008-09-03

    A review will be given of several important recent advances in both thermoelectrics research and industrial thermoelectric applications, which have attracted much attention, increasing incentives for developing advanced materials appropriate for large-scale applications of thermoelectric devices. One promising strategy is the development of materials with a dense packing of random nanostructures as a route for the sacle-up of thermoelectrics applications. The concepts involved in designing composite materials containing nanostructures for thermoelectric applications will be discussed in general terms. Specific application is made to the Bi{sub 2}Te{sub 3} nanocomposite system for use in power generation. Also emphasized are the scientific advantages of the nanocomposite approach for the simultaneous increase in the power factor and decrease of the thermal conductivity, along with the practical advantages of having bulk samples for property measurements and device applications. A straightforward path is identified for the scale-up of thermoelectric materials synthesis containing nanostructured constituents for use in thermoelectric applications. We end with some vision of where the field of thermoelectrics is now heading.

  14. Single-Molecule Investigations of Morphology and Mass Transport Dynamics in Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Higgins, Daniel A.; Park, Seok Chan; Tran-Ba, Khanh-Hoa; Ito, Takashi

    2015-07-01

    Nanostructured materials such as mesoporous metal oxides and phase-separated block copolymers form the basis for new monolith, membrane, and thin film technologies having applications in energy storage, chemical catalysis, and separations. Mass transport plays an integral role in governing the application-specific performance characteristics of many such materials. The majority of methods employed in their characterization provide only ensemble data, often masking the nanoscale, molecular-level details of materials morphology and mass transport. Single-molecule fluorescence methods offer direct routes to probing these characteristics on a single-molecule/single-nanostructure basis. This article provides a review of single-molecule studies focused on measurements of anisotropic diffusion, adsorption, partitioning, and confinement in nanostructured materials. Experimental methods covered include confocal and wide-field fluorescence microscopy. The results obtained promise to deepen our understanding of mass transport mechanisms in nanostructures, thus aiding in the realization of advanced materials systems.

  15. Single-Molecule Investigations of Morphology and Mass Transport Dynamics in Nanostructured Materials.

    PubMed

    Higgins, Daniel A; Park, Seok Chan; Tran-Ba, Khanh-Hoa; Ito, Takashi

    2015-01-01

    Nanostructured materials such as mesoporous metal oxides and phase-separated block copolymers form the basis for new monolith, membrane, and thin film technologies having applications in energy storage, chemical catalysis, and separations. Mass transport plays an integral role in governing the application-specific performance characteristics of many such materials. The majority of methods employed in their characterization provide only ensemble data, often masking the nanoscale, molecular-level details of materials morphology and mass transport. Single-molecule fluorescence methods offer direct routes to probing these characteristics on a single-molecule/single-nanostructure basis. This article provides a review of single-molecule studies focused on measurements of anisotropic diffusion, adsorption, partitioning, and confinement in nanostructured materials. Experimental methods covered include confocal and wide-field fluorescence microscopy. The results obtained promise to deepen our understanding of mass transport mechanisms in nanostructures, thus aiding in the realization of advanced materials systems.

  16. Methods for high volume production of nanostructured materials

    DOEpatents

    Ripley, Edward B [Knoxville, TN; Morrell, Jonathan S [Knoxville, TN; Seals, Roland D [Oak Ridge, TN; Ludtka, Gerald M [Oak Ridge, TN

    2011-03-22

    A system and method for high volume production of nanoparticles, nanotubes, and items incorporating nanoparticles and nanotubes. Microwave, radio frequency, or infrared energy vaporizes a metal catalyst which, as it condenses, is contacted by carbon or other elements such as silicon, germanium, or boron to form agglomerates. The agglomerates may be annealed to accelerate the production of nanotubes. Magnetic or electric fields may be used to align the nanotubes during their production. The nanotubes may be separated from the production byproducts in aligned or non-aligned configurations. The agglomerates may be formed directly into tools, optionally in compositions that incorporate other materials such as abrasives, binders, carbon-carbon composites, and cermets.

  17. Fabrication and optimization of nano-structured composites for energy storage

    NASA Astrophysics Data System (ADS)

    Carrington, Kenneth Russell

    This dissertation is focused on the development and characterization of a novel class of solid-state nano-structured composites for hydrogen storage based on silica aerogel. It is organized sequentially around experiments conducted to fabricate, optimize and characterize silica aerogel and the composites for hydrogen storage. First, the basics of nano-structured media, silica aerogel technology and solid-state hydrogen storage are introduced. Next, the fabrication and optimization of silica aerogel for hydrogen storage is described in detail. The key result is that varying fabrication parameters can improve the physical properties of the resultant silica aerogel in the context of hydrogen storage. The fabrication of solid-state nano-structured composites using chemical vapor infiltration is then discussed. A series of experiments is used to parameterize the fabrication process, which results in a collection of parameters that minimize variation and structural damage in the composites. Silica aerogel and the composites are then physically characterized using transmission electron microscopy, X-ray diffraction and porosimetry in order to investigate their nano-structuring. An overview of hydrogen storage characterization and two innovations that improve the accuracy and efficiency of hydrogen storage characterization of low-bulk density media like silica aerogel and the composites are then presented. Finally, the innovations are applied to silica aerogel and the composites to characterize their hydrogen storage performance. Silica aerogel and the composites are found to outperform the most common benchmark in physisorption media, and one composite in particular shows unique hydrogen storage performance.

  18. Precise 3D printing of micro/nanostructures using highly conductive carbon nanotube-thiol-acrylate composites

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Xiong, W.; Jiang, L. J.; Zhou, Y. S.; Lu, Y. F.

    2016-04-01

    Two-photon polymerization (TPP) is of increasing interest due to its unique combination of truly three-dimensional (3D) fabrication capability and ultrahigh spatial resolution of ~40 nm. However, the stringent requirements of non-linear resins seriously limit the material functionality of 3D printing via TPP. Precise fabrication of 3D micro/nanostructures with multi-functionalities such as high electrical conductivity and mechanical strength is still a long-standing challenge. In this work, TPP fabrication of arbitrary 3D micro/nanostructures using multi-walled carbon nanotube (MWNT)-thiolacrylate (MTA) composite resins has been developed. Up to 0.2 wt% MWNTs have been incorporated into thiol-acrylate resins to form highly stable and uniform composite photoresists without obvious degradation for one week at room temperature. Various functional 3D micro/nanostructures including woodpiles, micro-coils, spiral-like photonic crystals, suspended micro-bridges, micro-gears and complex micro-cars have been successfully fabricated. The MTA composite resin offers significant enhancements in electrical conductivity and mechanical strength, and on the same time, preserving high optical transmittance and flexibility. Tightly controlled alignment of MWNTs and the strong anisotropy effect were confirmed. Microelectronic devices including capacitors and resistors made of the MTA composite polymer were demonstrated. The 3D micro/nanofabrication using the MTA composite resins enables the precise 3D printing of micro/nanostructures of high electrical conductivity and mechanical strength, which is expected to lead a wide range of device applications, including micro/nano-electromechanical systems (MEMS/NEMS), integrated photonics and 3D electronics.

  19. Improved Silica Aerogel Composite Materials

    NASA Technical Reports Server (NTRS)

    Paik, Jong-Ah; Sakamoto, Jeffrey; Jones, Steven

    2008-01-01

    A family of aerogel-matrix composite materials having thermal-stability and mechanical- integrity properties better than those of neat aerogels has been developed. Aerogels are known to be excellent thermal- and acoustic-insulation materials because of their molecular-scale porosity, but heretofore, the use of aerogels has been inhibited by two factors: (1) Their brittleness makes processing and handling difficult. (2) They shrink during production and shrink more when heated to high temperatures during use. The shrinkage and the consequent cracking make it difficult to use them to encapsulate objects in thermal-insulation materials. The underlying concept of aerogel-matrix composites is not new; the novelty of the present family of materials lies in formulations and processes that result in superior properties, which include (1) much less shrinkage during a supercritical-drying process employed in producing a typical aerogel, (2) much less shrinkage during exposure to high temperatures, and (3) as a result of the reduction in shrinkage, much less or even no cracking.

  20. Metal-ceramic/ceramic nanostructured layered composites for solid oxide fuel cells by spark plasma sintering.

    PubMed

    Bezdorozhev, Oleksii; Borodianska, Hanna; Sakka, Yoshio; Vasylkiv, Oleg

    2014-06-01

    In this work, bi-layered Fe-Ni-Co-YSZ/YSZ nanostructured composites for solid oxide fuel cells were obtained using the spark plasma sintering (SPS) technique. The microstructures of the anode and electrolyte were controlled by optimization of SPS consolidation parameters. The resulting bilayers have a full dense YSZ electrolyte and porous Fe-Ni-Co/YSZ anode as well as crack-free and well-bonded anode/electrolyte interface. On the other hand, SPS under non-optimized processing parameters cannot yield the desired results. The high resistance to thermal stresses of the fabricated half-cells was achieved with Fe-Ni-Co/YSZ anode. The developed anode showed higher thermal compatibility with YSZ electrolyte than usual Ni/YSZ cermet. Thus, with the successful combination of SPS parameters and anode material, we have obtained bi-layers for SOFCs with required microstructure and thermal compatibility.

  1. Dendrimer-modified solid supports: nanostructured materials with potential drug allergy diagnostic applications.

    PubMed

    Ruiz-Sanchez, A J; Montañez, M I; Mayorga, C; Torres, M J; Kehr, N S; Vida, Y; Collado, D; Najera, F; De Cola, L; Perez-Inestrosa, E

    2012-01-01

    Complex functional materials consisting of bioactive molecules immobilized on solid supports present potential applications in biosensoring. Advances in the fabrication of these surface materials are of growing interest for antibody-based diagnosis. This work exploits dendrimers as versatile nanostructures for templating sensor surfaces and the critical role of the immobilization protocol in the solid supports cellulose and zeolites, of organic and inorganic composition respectively. The fabrication and characterization, including the degree of functionalization and reproducibility, of different nanostructured materials are described. To validate the approach, the fabricated supports were further used as a solid phase for developing a radioimmunoassay to detect immunoglobulin E (IgE) specific to penicillin, the antibody involved in immediate allergy responses to this drug. The dendrimer-modified supports provide assays with significantly enhanced sensitivity, as well as increase the availability of biomolecules for specific interaction and minimize nonspecific adsorptions through appropriate functionalization protocols in each case. The manufacturing methodology involved the use of a long, flexible hydrophilic spacer in the cellulose materials, and a higher surface density of the immobilized dendrimers in the zeolite crystals. The ability of hybrid zeolite materials in such biosensing applications was evaluated for the first time. The assays were validated in human serum samples from patients allergic to penicillin and from non-allergic controls. The specificity and improved sensitivity of the dendrimer- modified supports make these strategies versatile for different bioactive molecules and could have significant implications for the quantification of a wide range of specific IgE antibodies and other biomolecules of diagnostic interest.

  2. Review on advances in porous nanostructured nickel oxides and their composite electrodes for high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Sk, Md Moniruzzaman; Yue, Chee Yoon; Ghosh, Kalyan; Jena, Rajeeb Kumar

    2016-03-01

    Recently, porous nanostructured transition metal oxides with excellent electrochemical performance have become a new class of energy storage materials for supercapacitors. The ever-growing global demand of electrically powered devices makes it imperative to develop renewable, efficient and reliable electrochemical energy storage devices. This review article focuses on the Ni based transition metal oxides and their composite electrode materials including carbons, metals and transition metal oxides for supercapacitor applications, providing an overview on the charge mechanisms, methodologies and nanostructures discovered in recent years, and latest research findings. The NiO and their composites possess higher reversible capacity, good structural stability, and have been studied for usage as novel electrode materials for supercapacitors. Their fine-tuned physical and chemical properties make them ideal candidates for supercapacitor applications as they possess higher accessible electroactive sites, which will provide both high power density and also high energy density. Moreover, synergistic effects can be derived from the constituent materials of the NiO based composite electrodes. The potential problems like device fabrication, measurement techniques, and future prospects of utilizing these materials as supercapacitor electrodes highlighting the fundamental understanding of the relationship between electrochemical and structural performances are also discussed.

  3. Bioactivity and structural properties of nanostructured bulk composites containing Nb2O5 and natural hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Bonadio, T. G. M.; Sato, F.; Medina, A. N.; Weinand, W. R.; Baesso, M. L.; Lima, W. M.

    2013-06-01

    In this work, we investigate the bioactivity and structural properties of nanostructured bulk composites that are composed of Nb2O5 and natural hydroxyapatite (HAp) and are produced by mechanical alloying and powder metallurgy. X-ray diffraction and Raman spectroscopy data showed that the milling process followed by a heat treatment at 1000 °C induced chemical reactions along with the formation of the CaNb2O6, PNb9O25 and Ca3(PO4)2 phases. Rietveld refinement indicated significant changes in each phase weight fraction as a function of HAp concentration. These changes influenced the in vitro bioactivity of the material. XRD and FTIR analyses indicated that the composites exhibited bioactivity characteristics by forming a carbonated apatite layer when the composites were immersed in a simulated body fluid. The formed layers had a maximum thickness of 13 μm, as measured by confocal Raman spectroscopy and as confirmed by scanning electron microscopy. The results of this work suggest that the tested bulk composites are promising biomaterials for use in implants.

  4. Nanostructure of tetrafunctional epoxy resins and composites: Correlation to moisture absorption properties

    NASA Astrophysics Data System (ADS)

    Bolan, Brett Andrew

    The effect that changes in network topology, while maintaining a constant network polarity (i.e. thermodynamic driving force was kept constant), had upon the moisture absorption properties of an aerospace grade tetrafunctional epoxy (TGMDA) cured with multifunctional amines were investigated. Utilizing Positron Annihilation Lifetime Spectroscopy (PALS) to characterize the nanoscale structure of these epoxies, it was found that as the "static" hole volume (a measurement of packing defects at 0K) increased so did the equilibrium uptake. PALS studies of one of these resins cured to varying extents, found that this static amount increased with degree of cure indicating that the network becomes more open as a direct consequence of crosslinking. Polar groups, which are the attractive force for diffusion, are in the vicinity of these crosslinks, therefore it is believed that the increase in static hole volume results in exposing more polar groups for absorption. The diffusion coefficient, which is representative of the kinetic aspect of diffusion, was also investigated. It was discovered that the amount of nanohole volume in the polymer; whether the total, the static, or dynamic (i.e. thermally activated) does not correlate to the diffusion coefficient in anyway. Furthermore, at an isotherm the diffusion coefficients for all these materials were relatively constant. From this it is hypothesized that it is the similar sub-Tsb{g} motions of these resins which is the rate limiting step in diffusion. This was bolstered by the fact that the activation energy for diffusion and for the sub-Tsb{g} motions for these epoxies are of the same order of magnitude. The nanostructure of fiber reinforced epoxy composites (i.e. a boron/epoxy and a graphite/epoxy) were probed with the bulk PALS technique as well. It was observed that for the graphite/epoxy composite and its flash (i.e. no fibers present) cured under identical conditions, that the nanoholes in the composite were larger than

  5. Effect of composition and nanostructure on CO2/N-2 transport properties of supported alkyl-imidazolium block copolymer membranes

    SciTech Connect

    Nguyen, PT; Wiesenauer, EF; Gin, DL; Noble, RD

    2013-03-01

    Polymerized room-temperature ionic liquids (poly(RTIL)s) have garnered attention as new and interesting membrane materials for CO2/light gas separations because they combine the high CO2 affinity and thermal and chemical stability of RTILs, with the physical and mechanical properties of polymeric materials. Our group recently synthesized a new type of block copolymer (BCP) combining an imidazolium-based poly(RTIL) and an alkyl non-ionic polymer. These alkyl-b-ionic BCPs phase-separate into ordered nanostructures. Prior work investigating gas transport through phase-separated BCPs is very limited, and none has included RTIL-based BCP systems. However it has been shown that nanoscale phase-separation could facilitate gas transport via nanostructure orientation control or phase connectivity improvement. We have successfully made defect-free, thin-film composite membranes with these novel alkyl-imidazolium BCPs as a 3-20 mu m thick top layer, and determined their CO2/N-2 separation properties via single-gas permeability measurements and selectivity calculations. These new BCP materials were found to have distinct advantages over the analogous physical blends of the parent homopolymers with respect to membrane fabrication. The composition of the BCP top layer, which is directly connected to the type of nanostructure formed, was found to have a significant effect on CO2 permeability (i.e., it can increase CO2 permeability by two orders of magnitude up to an observed value of 9300 barrer). This improvement is mainly due to a large increase in the diffusion coefficient in the ordered nanostructures compared to amorphous BCP materials. (C) 2012 Elsevier B.V. All rights reserved.

  6. Nanostructured carbon materials based electrothermal air pump actuators

    NASA Astrophysics Data System (ADS)

    Liu, Qing; Liu, Luqi; Kuang, Jun; Dai, Zhaohe; Han, Jinhua; Zhang, Zhong

    2014-05-01

    Actuator materials can directly convert different types of energy into mechanical energy. In this work, we designed and fabricated electrothermal air pump-type actuators by utilization of various nanostructured carbon materials, including single wall carbon nanotubes (SWCNTs), reduced graphene oxide (r-GO), and graphene oxide (GO)/SWCNT hybrid films as heating elements to transfer electrical stimulus into thermal energy, and finally convert it into mechanical energy. Both the actuation displacement and working temperature of the actuator films show the monotonically increasing trend with increasing driving voltage within the actuation process. Compared with common polymer nanocomposites based electrothermal actuators, our actuators exhibited better actuation performances with a low driving voltage (<10 V), large generated stress (tens of MPa), high gravimetric density (tens of J kg-1), and short response time (few hundreds of milliseconds). Besides that, the pump actuators exhibited excellent stability under cyclic actuation tests. Among these actuators, a relatively larger actuation strain was obtained for the r-GO film actuator due to the intrinsic gas-impermeability nature of graphene platelets. In addition, the high modulus of the r-GO and GO/SWCNT films also guaranteed the large generated stress and high work density. Specifically, the generated stress and gravimetric work density of the GO/SWCNT hybrid film actuator could reach up to more than 50 MPa and 30 J kg-1, respectively, under a driving voltage of 10 V. The resulting stress value is at least two orders of magnitude higher than that of natural muscles (~0.4 MPa).Actuator materials can directly convert different types of energy into mechanical energy. In this work, we designed and fabricated electrothermal air pump-type actuators by utilization of various nanostructured carbon materials, including single wall carbon nanotubes (SWCNTs), reduced graphene oxide (r-GO), and graphene oxide (GO)/SWCNT hybrid

  7. Composite WO3/TiO2 nanostructures for high electrochromic activity

    DOE PAGES

    Reyes-Gil, Karla R.; Stephens, Zachary D.; Stavila, Vitalie; ...

    2015-01-06

    A composite material consisting of TiO2 nanotubes (NT) with WO3 electrodeposited on its surface has been fabricated, detached from its Ti substrate, and attached to a fluorine-doped tin oxide (FTO) film on glass for application to electrochromic (EC) reactions. Several adhesion layers were tested, finding that a paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length and WO3 concentration on the EC performancemore » were studied. As a result, the composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast, and longer memory time compared with the pure WO3 and TiO2 materials« less

  8. Nanostructured carbon materials based electrothermal air pump actuators.

    PubMed

    Liu, Qing; Liu, Luqi; Kuang, Jun; Dai, Zhaohe; Han, Jinhua; Zhang, Zhong

    2014-06-21

    Actuator materials can directly convert different types of energy into mechanical energy. In this work, we designed and fabricated electrothermal air pump-type actuators by utilization of various nanostructured carbon materials, including single wall carbon nanotubes (SWCNTs), reduced graphene oxide (r-GO), and graphene oxide (GO)/SWCNT hybrid films as heating elements to transfer electrical stimulus into thermal energy, and finally convert it into mechanical energy. Both the actuation displacement and working temperature of the actuator films show the monotonically increasing trend with increasing driving voltage within the actuation process. Compared with common polymer nanocomposites based electrothermal actuators, our actuators exhibited better actuation performances with a low driving voltage (<10 V), large generated stress (tens of MPa), high gravimetric density (tens of J kg(-1)), and short response time (few hundreds of milliseconds). Besides that, the pump actuators exhibited excellent stability under cyclic actuation tests. Among these actuators, a relatively larger actuation strain was obtained for the r-GO film actuator due to the intrinsic gas-impermeability nature of graphene platelets. In addition, the high modulus of the r-GO and GO/SWCNT films also guaranteed the large generated stress and high work density. Specifically, the generated stress and gravimetric work density of the GO/SWCNT hybrid film actuator could reach up to more than 50 MPa and 30 J kg(-1), respectively, under a driving voltage of 10 V. The resulting stress value is at least two orders of magnitude higher than that of natural muscles (∼ 0.4 MPa).

  9. Semiconductor nanostructure-based photovoltaic solar cells.

    PubMed

    Zhang, Genqiang; Finefrock, Scott; Liang, Daxin; Yadav, Gautam G; Yang, Haoran; Fang, Haiyu; Wu, Yue

    2011-06-01

    Substantial efforts have been devoted to design, synthesize, and integrate various semiconductor nanostructures for photovoltaic (PV) solar cells. In this article, we will review the recent progress in this exciting area and cover the material chemistry and physics related to all-inorganic nanostructure solar cells, hybrid inorganic nanostructure-conductive polymer composite solar cells, and dye-sensitized solar cells.

  10. Semiconductor nanostructure-based photovoltaic solar cells

    NASA Astrophysics Data System (ADS)

    Zhang, Genqiang; Finefrock, Scott; Liang, Daxin; Yadav, Gautam G.; Yang, Haoran; Fang, Haiyu; Wu, Yue

    2011-06-01

    Substantial efforts have been devoted to design, synthesize, and integrate various semiconductor nanostructures for photovoltaic (PV) solar cells. In this article, we will review the recent progress in this exciting area and cover the material chemistry and physics related to all-inorganic nanostructure solar cells, hybrid inorganic nanostructure-conductive polymer composite solar cells, and dye-sensitized solar cells.

  11. FIBER-REINFORCED METALLIC COMPOSITE MATERIALS.

    DTIC Science & Technology

    COMPOSITE MATERIALS), (*FIBER METALLURGY, TITANIUM ALLOYS , NICKEL ALLOYS , REINFORCING MATERIALS, TUNGSTEN, WIRE, MOLYBDENUM ALLOYS , COBALT ALLOYS , CHROMIUM ALLOYS , ALUMINUM ALLOYS , MECHANICAL PROPERTIES, POWDER METALLURGY.

  12. Efficient and versatile fibrous adsorbent based on magnetic amphiphilic composites of chrysotile/carbon nanostructures for the removal of ethynilestradiol.

    PubMed

    Teixeira, Ana Paula C; Purceno, Aluir D; de Paula, Camila C A; da Silva, Julio César C; Ardisson, José D; Lago, Rochel M

    2013-03-15

    In this work, chrysotile was used as support to grow carbon nanotubes and nanofibers to produce fibrous amphiphilic magnetic nanostructured composites. Iron impregnated on the chrysotile surface at 1, 5 and 15 wt% was used as catalyst to grow carbon nanostructures by CVD (chemical vapor deposition) with ethanol at 800°C. Raman, TG/DTA, Mössbauer, XRD, BET, SEM, TEM, elemental analyses and contact angle measurements suggested the formation of a complex amphiphilic material containing up to 21% of nanostructured hydrophobic carbon supported on hydrophilic Mg silicate fibers with magnetic Fe cores protected by carbon coating. Adsorption tests for the hormone ethynilestradiol (EE), a hazardous water contaminant, showed remarkable adsorption capacities even compared to high surface area activated carbon and multiwall carbon nanotubes. These results are discussed in terms of the hydrophobic surface of the carbon nanotubes and nanofibers completely exposed and accessible for the adsorption of the EE molecules combined with the hydrophilic Mg silicate surface which allows good dispersion in water. The composites are magnetic and after adsorption the dispersed particles can be removed by a simple magnetic process. Moreover, the fibrous composites can be conformed as threads, screens and pellets to produce different filtering media.

  13. Supramolecular chirality in self-assembled soft materials: regulation of chiral nanostructures and chiral functions.

    PubMed

    Zhang, Li; Qin, Long; Wang, Xiufeng; Cao, Hai; Liu, Minghua

    2014-10-29

    Supramolecular chirality, which arises from the nonsymmetric spatial arrangement of components in the self-assembly systems, has gained great attention owing to its relation to the natural biological structures and the possible new functions in advanced materials. During the self-assembling process, both chiral and achiral components are possible to form chiral nanostructures. Therefore, it becomes an important issue how to fabricate these molecular components into chiral nanostructures. Furthermore, once the chiral nanostructure is obtained, will it show new functions that simple component molecule could not? In this research news, we report our recent development in the regulation of chiral nanostructures in soft gels or vesicle materials. We have further developed several new functions pertaining to the soft gel materials, which single chiral molecules could not perform, such as the chiroptical switch, chiral recognition and the asymmetry catalysis.

  14. Nanostructured materials for ocular delivery: nanodesign for enhanced bioadhesion, transepithelial permeability and sustained delivery

    PubMed Central

    Kim, Jean; Schlesinger, Erica B; Desai, Tejal A

    2015-01-01

    Effective drug delivery to the eye is an ongoing challenge due to poor patient compliance coupled with numerous physiological barriers. Eye drops for the front of the eye and ocular injections for the back of the eye are the most prevalent delivery methods, both of which require relatively frequent administration and are burdensome to the patient. Novel drug delivery techniques stand to drastically improve safety, efficacy and patient compliance for ocular therapeutics. Remarkable advances in nanofabrication technologies make the application of nanostructured materials to ocular drug delivery possible. This article focuses on the use of nanostructured materials with nanoporosity or nanotopography for ocular delivery. Specifically, we discuss nanotopography for enhanced bioadhesion and permeation and nanoporous materials for controlled release drug delivery. As examples, application of polymeric nanostructures for greater transepithelial permeability, nanostructured microparticles for enhanced preocular retention time and nanoporous membranes for tuning drug release profile are covered. PMID:26652282

  15. Nanostructured Composites: Effective Mechanical Property Determination of Nanotube Bundles

    NASA Technical Reports Server (NTRS)

    Saether, E.; Pipes, R. B.; Frankland, S. J. V.

    2002-01-01

    Carbon nanotubes naturally tend to form crystals in the form of hexagonally packed bundles or ropes that should exhibit a transversely isotropic constitutive behavior. Although the intratube axial stiffness is on the order of 1 TPa due to a strong network of delocalized bonds, the intertube cohesive strength is orders of magnitude less controlled by weak, nonbonding van der Waals interactions. An accurate determination of the effective mechanical properties of nanotube bundles is important to assess potential structural applications such as reinforcement in future composite material systems. A direct method for calculating effective material constants is developed in the present study. The Lennard-Jones potential is used to model the nonbonding cohesive forces. A complete set of transverse moduli are obtained and compared with existing data.

  16. Synthesis of nanostructured materials for biosensor and fuel cell applications

    NASA Astrophysics Data System (ADS)

    Gil, Maria Paula

    Nanotechnology has attracted the attention of many different fields due to the new and exiting possibilities it entails. However, the future of nanotechnology depends on (i) the successful understanding and discovery of material properties at the nanoscale, (ii) efficient manufacture of nanoscale materials, and (iii) most importantly, incorporation of nanomaterials into real world applications and devices. The purpose of this research is to synthesize macroscale materials for applications such as fuel cell membranes or biosensors by assembly or modification at the nanoscale. This research is concentrated in two main projects. The first project focuses on the direct synthesis of a PEEK fuel cell membrane from sulfonated monomers with nanoscale features. S-PEEK membranes were evaluated for possible fuel cell applications by determining the degree of sulfonation, water swelling, proton conductivity, methanol diffusivity and thermal stability. As synthesized S-PEEK membranes exhibit conductivities (25°C) from 0.02--0.07 S/cm, water swelling from 13--54%, ion-exchange capacities (IEC) from 0.7--1.5 mmol/g and methanol diffusion coefficients from 3 x 10-7 --5 x 10-8 cm2/s at 25°C. These diffusion coefficients are much lower than that of NafionRTM (2 x 10-6 cm2/s), making S-PEEK membranes a good alternative to reduce problems associated with high methanol crossover in direct methanol fuel cells. The second project consists of synthesizing (2D) or (3D) nanowire thin film Pt electrodes for applications as glucose sensors. Although platinum nanowires have shown to have unique properties, it is still challenging to fabricate nanowire devices such as sensors. This research reports the fabrication of platinum nanowires into continuous thin film electrodes and the application as biosensors. The electrodes were synthesized by the following steps: (1) construction of a nanostructured mesoporous thin film template by self-assembly of surfactant and silicate species, (2

  17. Composite materials for fusion applications

    SciTech Connect

    Jones, R.H.; Henager, C.H. Jr.; Hollenberg, G.W.

    1991-10-01

    Ceramic matrix composites, CMCs, are being considered for advanced first-wall and blanket structural applications because of their high-temperature properties, low neutron activation, low density and low coefficient of expansion coupled with good thermal conductivity and corrosion behavior. This paper presents a review and analysis of the hermetic, thermal conductivity, corrosion, crack growth and radiation damage properties of CMCs. It was concluded that the leak rates of a gaseous coolant into the plasma chamber or tritium out of the blanket could exceed design criteria if matrix microcracking causes existing porosity to become interconnected. Thermal conductivities of unirradiated SiC/SiC and C/SiC materials are about 1/2 to 2/3 that of Type 316 SS whereas the thermal conductivity for C/C composites is seven times larger. The thermal stress figure-of-merit value for CMCs exceeds that of Type 316 SS for a single thermal cycle. SiC/SiC composites are very resistant to corrosion and are expected to be compatible with He or Li coolants if the O{sub 2} concentrations are maintained at the appropriate levels. CMCs exhibit subcritical crack growth at elevated temperatures and the crack velocity is a function of the corrosion conditions. The radiation stability of CMCs will depend on the stability of the fiber, microcracking of the matrix, and the effects of gaseous transmutation products on properties. 23 refs., 14 figs., 1 tab.

  18. Enhancing thermoelectric properties of organic composites through hierarchical nanostructures

    PubMed Central

    Zhang, Kun; Zhang, Yue; Wang, Shiren

    2013-01-01

    Organic thermoelectric (TE) materials are very attractive due to easy processing, material abundance, and environmentally-benign characteristics, but their potential is significantly restricted by the inferior thermoelectric properties. In this work, noncovalently functionalized graphene with fullerene by π-π stacking in a liquid-liquid interface was integrated into poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate). Graphene helps to improve electrical conductivity while fullerene enhances the Seebeck coefficient and hinders thermal conductivity, resulting in the synergistic effect on enhancing thermoelectric properties. With the integration of nanohybrids, the electrical conductivity increased from ~10000 to ~70000 S/m, the thermal conductivity changed from 0.2 to 2 W·K−1m−1 while the Seebeck coefficient was enhanced by around 4-fold. As a result, nanohybrids-based polymer composites demonstrated the figure of merit (ZT) as high as 6.7 × 10−2, indicating an enhancement of more than one order of magnitude in comparison to single-phase filler-based polymer composites with ZT at the level of 10−3. PMID:24336319

  19. Preferentially grown nanostructured MgB2C2: A new material for lightening applications

    NASA Astrophysics Data System (ADS)

    Singh, Paviter; Singh, Kulwinder; Kaur, Manpreet; Kaur, Harpreet; Singh, Bikmramjeet; Kaur, Gurpreet; Kaur, Manjot; Kumar, Manjeet; Kaur, Kamalpreet; Bala, Rajni; Kumar, Akshay

    2017-03-01

    Nanostructured MgB2C2 is a promising candidate as functional material. High Temperature synthesis conditions were the limitations for its exploitation in materials research. Present study deals with the synthesis of specifically oriented nanostructured MgB2C2 at relatively low temperature by solvothermal route. The synthesis conditions are modified to grow these nanostructures in least dense plane (002). Optical properties are explored for the first time. XRD analysis confirms the formation of MgB2C2 phase. Morphological analysis (Transmission/Scanning Electron Microscopy) indicated that the synthesized material is in nano range. Photoluminescence study shows that the synthesized material emits light in visible spectrum when excited at 380 nm. The quantum efficiency of synthesized material calculated by De Mello's method is approximately 23% which makes the material efficient enough for lightening applications.

  20. FEM analysis of spur gears forging from nano-structured materials

    NASA Astrophysics Data System (ADS)

    Salcedo, D.; Luis-Pérez, C. J.; Luri, R.; León, J.

    2012-04-01

    The ECAE process is a novel technology which allows us to obtain materials with sub-micrometric and/or nanometric grain size as a result of accumulating very high levels of plastic deformation in the presence of a high hydrostatic pressure. This avoids the fracture of the material and allows us to obtain very high values of plastic deformation (ɛ >>1). Therefore, these nano-structured materials can be used as starting materials for other manufacturing processes such as: extrusion, rolling and forging, among others; with the advantage of providing nanostructure and hence, improved mechanical properties. In this present work, the forging by finite element method (FEM) of materials that have been previously processed by ECAE is analyzed. MSC. MarcTM software will be employed with the aim of analyzing the possibility of manufacturing mechanical components (spur gears) from materials nano-structured by ECAE.

  1. Sorptive removal of trinitroglycerin (TNG) from water using nanostructured silica-based materials.

    PubMed

    Saad, Rabih; Thibutot, Sonia; Ampleman, Guy; Hawari, Jalal

    2010-01-01

    Trinitroglycerin (TNG), a nitrate ester, is widely used in the pharmaceutical industry for the treatment of angina pectoris (chest pain) and by the military for the manufacturing of dynamite and propellants. Currently, TNG is considered as a key environmental contaminant due to the discharge of wastewater tainted with the chemical from various military and pharmaceutical industries. The present study describes the use of a nanostructured silica material (Mobil Composite Material no. 48 [MCM-48]) prepared by mixing tetraethylorthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) to remove TNG from water. The sorption of TNG onto MCM-48 rapidly reached equilibrium within 1 h. Sorption kinetics were best described using a pseudo-second order model, whereas sorption isotherms were best interpreted using the Langmuir model. The latter gave a maximum sorption capacity of 55.2 mg g(-1) at 40 degrees C. The enthalpy and entropy of TNG sorption onto MCM-48 were 1.89 kJ mol(-1) and 79.0 J mol(-1).K(-1), indicating the endothermic nature of the TNG sorption onto MCM-48. When MCM-48 was heated at 540 degrees C for 5 h, the resulting calcined material (absence of the surfactant) did not sorb TNG, suggesting that the surfactant component of the nanomaterial was responsible for TNG sorption. Finally, we found that MCM-48 lost approximately 30% of its original sorption capacity after five sorption-desorption cycles. In conclusion, the nanostructured silica based sorbent, with high sorption capacity and remarkable reusability, should constitute the basis for the development of an effective technology for the removal of TNG from contaminated water.

  2. Nanostructured Graphene-Titanium Dioxide Composites Synthesized by a Single-Step Aerosol Process for Photoreduction of Carbon Dioxide

    PubMed Central

    Wang, Wei-Ning; Jiang, Yi; Fortner, John D.; Biswas, Pratim

    2014-01-01

    Abstract Photocatalytic reduction of carbon dioxide (CO2) to hydrocarbons by using nanostructured materials activated by solar energy is a promising approach to recycling CO2 as a fuel feedstock. CO2 photoreduction, however, suffers from low efficiency mainly due to the inherent drawback of fast electron-hole recombination in photocatalysts. This work reports the synthesis of nanostructured composites of titania (TiO2) nanoparticles (NPs) encapsulated by reduced graphene oxide (rGO) nanosheets via an aerosol approach. The role of synthesis temperature and TiO2/GO ratio in CO2 photoreduction was investigated. As-prepared nanocomposites demonstrated enhanced CO2 conversion performance as compared with that of pristine TiO2 NPs due to the strong electron trapping capability of the rGO nanosheets. PMID:25053879

  3. Space processing of composite materials

    NASA Technical Reports Server (NTRS)

    Steurer, W. H.; Kaye, S.

    1975-01-01

    Materials and processes for the testing of aluminum-base fiber and particle composites, and of metal foams under extended-time low-g conditions were investigated. A wetting and dispersion technique was developed, based on the theory that under the absence of a gas phase all solids are wetted by liquids. The process is characterized by a high vacuum environment and a high temperature cycle. Successful wetting and dispersion experiments were carried out with sapphire fibers, whiskers and particles, and with fibers of silicon carbide, pyrolytic graphite and tungsten. The developed process and facilities permit the preparation of a precomposite which serves as sample material for flight experiments. Low-g processing consists then merely in the uniform redistribution of the reinforcements during a melting cycle. For the preparation of metal foams, gas generation by means of a thermally decomposing compound was found most adaptable to flight experiments. For flight experiments, the use of compacted mixture of the component materials limits low-g processing to a simple melt cycle.

  4. Modeling and characterization of the elastic behavior of interfaces in nanostructured materials: From an atomistic description to a continuum approach

    NASA Astrophysics Data System (ADS)

    Dingreville, Remi

    the effects of surface free energy on the effective modulus of nano-particles, nano-wires and nano-films as well as nanostructured crystalline materials and propose a general framework valid for any shape of nanostructural elements/nano-inclusions (integral forms) that characterizes the size-dependency of the elastic properties. This approach bridges the gap between discrete systems (atomic level interactions) and continuum mechanics. Finally this continuum outline is used to understand the effects of surfaces on the overall behavior of nano-size structural elements (particles, films, fibers, etc.) and nanostructured materials. More specifically we will discuss the impact of surface relaxation, surface elasticity and non-linearity of the underlying bulk on the properties nanostructured materials. In terms of engineering applications, this approach proves to be a useful tool for multi-scale modeling of heterogeneous materials with nanometer scale microstructures and provides insights on surface properties for several material systems; these will be very useful in many fields including surface science, tribology, fracture mechanics, adhesion science and engineering, and more. It will accelerate the insertion of nano-size structural elements, nano-composite and nanocrystalline materials into engineering applications.

  5. Mechanics of interfacial composite materials.

    PubMed

    Subramaniam, Anand Bala; Abkarian, Manouk; Mahadevan, L; Stone, Howard A

    2006-11-21

    Recent experiments and simulations have demonstrated that particle-covered fluid/fluid interfaces can exist in stable nonspherical shapes as a result of the steric jamming of the interfacially trapped particles. The jamming confers the interface with solidlike properties. We provide an experimental and theoretical characterization of the mechanical properties of these armored objects, with attention given to the two-dimensional granular state of the interface. Small inhomogeneous stresses produce a plastic response, while homogeneous stresses produce a weak elastic response. Shear-driven particle-scale rearrangements explain the basic threshold needed to obtain the near-perfect plastic deformation that is observed. Furthermore, the inhomogeneous stress state of the interface is exhibited experimentally by using surfactants to destabilize the particles on the surface. Since the interfacially trapped particles retain their individual characteristics, armored interfaces can be recognized as a kind of composite material with distinct chemical, structural, and mechanical properties.

  6. Durability of polymer composite materials

    NASA Astrophysics Data System (ADS)

    Liu, Liu

    The purpose of this research is to examine structural durability of advanced composite materials under critical loading conditions, e.g., combined thermal and mechanical loading and shear fatigue loading. A thermal buckling model of a burnt column, either axially restrained or under an axial applied force was developed. It was predicted that for a column exposed to the high heat flux under simultaneous constant compressive load, the response of the column is the same as that of an imperfection column; the instability of the burnt column happens. Based on the simplified theoretical prediction, the post-fire compressive behavior of fiberglass reinforced vinyl-ester composite columns, which have been exposed to high heat flux for a certain time was investigated experimentally, the post-fire compressive strength, modulus and failure mode were determined. The integrity of the same column under constant compressive mechanical loading combined with heat flux exposure was examined using a specially designed mechanical loading fixture that mounted directly below a cone calorimeter. All specimens in the experiments exhibited compressive instability. The experimental results show a thermal bending moment exists and has a significant influence on the structural behavior, which verified the thermal buckling model. The trend of response between the deflection of the column and exposure time is similar to that predicted by the model. A new apparatus was developed to study the monotonic shear and cyclic-shear behavior of sandwich structures. Proof-of-concept experiments were performed using PVC foam core polymeric sandwich materials. Shear failure occurred by the extension of cracks parallel to the face-sheet/core interface, the shear modulus degraded with the growth of fatigue damage. Finite element analysis was conducted to determine stress distribution in the proposed specimen geometry used in the new technique. Details for a novel apparatus used for the fatigue testing of thin

  7. Fabrication and characterization of nanostructured titanate materials by the hydrothermal treatment method.

    PubMed

    Doong, Ruey-an; Kao, I-ling

    2008-01-01

    The synthesis and characterization of one-dimensional (1-D) tubular and fibrous nanostructured materials have recently received highly attention. Various morphologies of 1-D nanostructured titanate materials including nanosheets, nanotubes, nanowires, and nanoribbons have recently been successfully synthesized using the alkaline hydrothermal method. In spite of the controversy of the chemical structures and formation mechanisms, titanate nanostructures have attracted much attention on applications of dye-sensitized solar cell, hydrogen sensing, lithium storage and photocatalysis because of their unique features of high specific surface area, ion-exchange capacity and aspect ratio, and unique optical and electrochemical properties. The morphology and microstructure of titanate nanostructures are highly dependent on the preparation conditions. In this review, we highlight the synthesis of TiO(2)-derived nanomaterials under various hydrothermal conditions. The patents for fabrication of various morphologies of nanostructures are also introduced. Effects of preparation parameters including hydrothermal temperature, duration, alkaline concentration, starting materials, and post-treatment on the morphology and microstructure of titanate nanomaterials are reviewered. In addition, the microwave-assisted method for fabrication of 1-D titanate nanostructures is discussed and compared. The applications of titanate nanomaterials in photocatalysis, ion-exchange, and lithium storages are also introduced.

  8. Morphology and composition controlled synthesis of flower-like silver nanostructures

    NASA Astrophysics Data System (ADS)

    Zhou, Ning; Li, Dongsheng; Yang, Deren

    2014-06-01

    Flower-like silver nanostructures with controlled morphology and composition were prepared through wet-chemical synthesis. The reaction rate is simply manipulated by the amount of catalyzing agent ammonia added which is the key point to determine the ratio of hexagonal close-packed (HCP) to face-centered cubic (FCC) phase in silver nanostructures. The existence of formic acid that is the oxidation product of aldehyde group is demonstrated to play a crucial role in achieving the metastable HCP crystal structures by replacing ionic surfactants with polyvinylpyrrolidone (PVP). Utilizing flower-like silver nanostructures as surface-enhanced Raman scattering (SERS) substrates, Raman signal of Rhodamine 6G, or 4-aminothiophenol with concentration as low as 10-7 M was detected. Moreover, it is demonstrated that phase composition has no direct relation to the SERS enhancing factor which is mainly determined by the amount of hot spots.

  9. Morphology and composition controlled synthesis of flower-like silver nanostructures

    PubMed Central

    2014-01-01

    Flower-like silver nanostructures with controlled morphology and composition were prepared through wet-chemical synthesis. The reaction rate is simply manipulated by the amount of catalyzing agent ammonia added which is the key point to determine the ratio of hexagonal close-packed (HCP) to face-centered cubic (FCC) phase in silver nanostructures. The existence of formic acid that is the oxidation product of aldehyde group is demonstrated to play a crucial role in achieving the metastable HCP crystal structures by replacing ionic surfactants with polyvinylpyrrolidone (PVP). Utilizing flower-like silver nanostructures as surface-enhanced Raman scattering (SERS) substrates, Raman signal of Rhodamine 6G, or 4-aminothiophenol with concentration as low as 10−7 M was detected. Moreover, it is demonstrated that phase composition has no direct relation to the SERS enhancing factor which is mainly determined by the amount of hot spots. PMID:24994957

  10. Synthesis of branched metal nanostructures with controlled architecture and composition

    NASA Astrophysics Data System (ADS)

    Ortiz, Nancy

    On account of their small size, metal nanoparticles are proven to be outstanding catalysts for numerous chemical transformations and represent promising platforms for applications in the fields of electronics, chemical sensing, medicine, and beyond. Many properties of metal nanoparticles are size-dependent and can be further manipulated through their shape and architecture (e.g., spherical vs. branched). Achieving morphology control of nanoparticles through solution-based techniques has proven challenging due to limited knowledge of morphology development in nanosyntheses. To overcome these complications, a systematic examination of the local ligand environment of metal precursors on nanostructure formation was undertaken to evaluate its contribution to nanoparticle nucleation rate and subsequent growth processes. Specifically, this thesis will provide evidence from ex situ studies---Transmission Electron Microscopy (TEM) and UV-visible spectroscopy (UV-Vis)---that support the hypothesis that strongly coordinated ligands delay burst-like nucleation to generate spherical metal nanoparticles and ligands with intermediate binding affinity regulate the gradual reduction of metal precursors to promote aggregated assembly of nanodendrites. These ex situ studies were coupled with a new in situ perspective, providing detailed understanding of metal precursor transformation, its direct relation to nanoparticle morphology development, and the ligand influence towards the formation of structurally complex metal nanostructures, using in situ synchrotron X-ray Diffraction (XRD) and Ultra Small-Angle X-ray Scattering (USAXS). The principles extracted from the study of monometallic nanostructure formation were also found to be generally applicable to the synthesis of bimetallic nanostructures, e.g., Pd-Pt architectures, with either core-shell or alloyed structures that were readily achieved by ligand selection. These outcomes provide a direct connection between fundamental

  11. Delamination growth in composite materials

    NASA Technical Reports Server (NTRS)

    Gillespie, J. W., Jr.; Carlsson, L. A.; Pipes, R. B.; Rothschilds, R.; Trethewey, B.; Smiley, A.

    1986-01-01

    The Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) specimens are employed to characterize MODE I and MODE II interlaminar fracture resistance of graphite/epoxy (CYCOM 982) and graphite/PEEK (APC2) composites. Sizing of test specimen geometries to achieve crack growth in the linear elastic regime is presented. Data reduction schemes based upon beam theory are derived for the ENF specimen and include the effects of shear deformation and friction between crack surfaces on compliance, C, and strain energy release rate, G sub II. Finite element (FE) analyses of the ENF geometry including the contact problem with friction are presented to assess the accuracy of beam theory expressions for C and G sub II. Virtual crack closure techniques verify that the ENF specimen is a pure Mode II test. Beam theory expressions are shown to be conservative by 20 to 40 percent for typical unidirectional test specimen geometries. A FE parametric study investigating the influence of delamination length and depth, span, thickness and material properties on G sub II is presented. Mode I and II interlaminar fracture test results are presented. Important experimental parameters are isolated, such as precracking techniques, rate effects, and nonlinear load-deflection response. It is found that subcritical crack growth and inelastic materials behavior, responsible for the observed nonlinearities, are highly rate-dependent phenomena with high rates generally leading to linear elastic response.

  12. Thin film dielectric composite materials

    DOEpatents

    Jia, Quanxi; Gibbons, Brady J.; Findikoglu, Alp T.; Park, Bae Ho

    2002-01-01

    A dielectric composite material comprising at least two crystal phases of different components with TiO.sub.2 as a first component and a material selected from the group consisting of Ba.sub.1-x Sr.sub.x TiO.sub.3 where x is from 0.3 to 0.7, Pb.sub.1-x Ca.sub.x TiO.sub.3 where x is from 0.4 to 0.7, Sr.sub.1-x Pb.sub.x TiO.sub.3 where x is from 0.2 to 0.4, Ba.sub.1-x Cd.sub.x TiO.sub.3 where x is from 0.02 to 0.1, BaTi.sub.1-x Zr.sub.x O.sub.3 where x is from 0.2 to 0.3, BaTi.sub.1-x Sn.sub.x O.sub.3 where x is from 0.15 to 0.3, BaTi.sub.1-x Hf.sub.x O.sub.3 where x is from 0.24 to 0.3, Pb.sub.1-1.3x La.sub.x TiO.sub.3+0.2x where x is from 0.23 to 0.3, (BaTiO.sub.3).sub.x (PbFeo.sub.0.5 Nb.sub.0.5 O.sub.3).sub.1-x where x is from 0.75 to 0.9, (PbTiO.sub.3).sub.- (PbCo.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.1 to 0.45, (PbTiO.sub.3).sub.x (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.2 to 0.4, and (PbTiO.sub.3).sub.x (PbFe.sub.0.5 Ta.sub.0.5 O.sub.3).sub.1-x where x is from 0 to 0.2, as the second component is described. The dielectric composite material can be formed as a thin film upon suitable substrates.

  13. Nano-structured composite cathodes for intermediate temperature solid oxide fuel cells via an infiltration/impregnation technique

    SciTech Connect

    Jiang, Zhiyi; Xia, Changrong; Chen, Fanglin

    2010-02-12

    Solid oxide fuel cells (SOFCs) are high temperature energy conversion devices working efficiently and environmental friendly. SOFC requires a functional cathode with high electrocatalytic activity for the electrochemical reduction of oxygen. The electrode is often fabricated at high temperature to achieve good bonding between the electrode and electrolyte. The high temperature not only limits material choice but also results in coarse particles with low electrocatalytic activity. Nano-structured electrodes fabricated at low temperature by an infiltration/impregnation technique have shown many advantages including superior activity and wider range of material choices. The impregnation technique involves depositing nanoparticle catalysts into a pre-sintered electrode backbone. Two basic types of nano-structures are developed since the electrode is usually a composite consists of an electrolyte and an electrocatalyst. One is infiltrating electronically conducting nano-catalyst into a single phase ionic conducting backbone, while the other is infiltrating ionically conducting nanoparticles into a single phase electronically conducting backbone. In addition, nanoparticles of the electrocatalyst, electrolyte and other oxides have also been infiltrated into mixed conducting backbones. These nano-structured cathodes are reviewed here regarding the preparation methods, their electrochemical performance, and stability upon thermal cycling.

  14. Composite materials for space structures

    NASA Technical Reports Server (NTRS)

    Tenney, D. R.; Sykes, G. F.; Bowles, D. E.

    1985-01-01

    The use of advanced composites for space structures is reviewed. Barriers likely to limit further applications of composites are discussed and highlights of research to improve composites are presented. Developments in composites technology which could impact spacecraft systems are reviewed to identify technology needs and opportunities.

  15. Polyolefin composites containing a phase change material

    DOEpatents

    Salyer, Ival O.

    1991-01-01

    A composite useful in thermal energy storage, said composite being formed of a polyolefin matrix having a phase change material such as a crystalline alkyl hydrocarbon incorporated therein, said polyolefin being thermally form stable; the composite is useful in forming pellets, sheets or fibers having thermal energy storage characteristics; methods for forming the composite are also disclosed.

  16. Nanostructure and optoelectronic phenomena in germanium-transparent conductive oxide (Ge:TCO) composites

    NASA Astrophysics Data System (ADS)

    Shih, Grace Hwei-Pyng

    Nanostructured composites are attracting intense interest for electronic and optoelectronic device applications, specifically as active elements in thin film photovoltaic (PV) device architectures. These systems implement fundamentally different concepts of enhancing energy conversion efficiencies compared to those seen in current commercial devices. This is possible through considerable flexibility in the manipulation of device-relevant properties through control of the interplay between the nanostructure and the optoelectronic response. In the present work, inorganic nanocomposites of semiconductor Ge embedded in transparent conductive indium tin oxide (ITO) as well as Ge in zinc oxide (ZnO) were produced by a single step RF-magnetron sputter deposition process. It is shown that, by controlling the design of the nanocomposites as well as heat treatment conditions, decreases in the physical dimensions of Ge nanophase size provided an effective tuning of the optical absorption and charge transport properties. This effect of changes in the optical properties of nanophase semiconductors with respect to size is known as the quantum confinement effect. Variation in the embedding matrix material between ITO and ZnO with corresponding characterization of optoelectronic properties exhibit notable differences in the presence and evolution of an interfacial oxide within these composites. Further studies of interfacial structures were performed using depth-profiling XPS and Raman spectroscopy, while study of the corresponding electronic effects were performed using room temperature and temperature-dependent Hall Effect. Optical absorption was noted to shift to higher onset energies upon heat treatment with a decrease in the observed Ge domain size, indicating quantum confinement effects within these systems. This contrasts to previous investigations that have involved the introduction of nanoscale Ge into insulating, amorphous oxides. Comparison of these different matrix

  17. Silicon-embedded copper nanostructure network for high energy storage

    DOEpatents

    Yu, Tianyue

    2016-03-15

    Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both. The metal nanostructure growth can nucleate in solution and on silicon nanostructure surfaces.

  18. Nanostructured metal-polyaniline composites and applications thereof

    SciTech Connect

    Wang, Hsing-Lin; Li, Wenguang; Bailey, James A.; Gao, Yuan

    2012-10-02

    Metal-polyaniline (PANI) composites are provided together with a process of preparing such composites by an electrodeless process. The metal of the composite can have nanoscale structural features and the composites can be used in applications such as catalysis for hydrogenation reactions and for analytical detection methods employing SERS.

  19. Design, fabrication, and testing of nanostructured carbons and composites

    NASA Astrophysics Data System (ADS)

    Wang, Zhiyong

    cubic, spherical and tetrapod shapes were also synthesized. In addition, new methods were developed to assemble nanocomposites of bifunctional catalyst components. These materials were designed for the potential direct conversion of synthesis gas to clean liquid fuels. Coatings of zeolite and cobalt nanoparticles were fabricated on 3DOM promoted zirconia. The 3DOM zirconia-based nanocomposites were characterized by a wide variety of techniques to illustrate their morphologies, internal structures, chemical compositions, porosity, and crystallographic phases.

  20. Quantum Simulations of Materials and Nanostructures (Q-SIMAN). Final Report

    SciTech Connect

    Galli, Giulia; Bai, Zhaojun; Ceperley, David; Cai, Wei; Gygi, Francois; Marzari, Nicola; Pickett, Warren; Spaldin, Nicola; Fattebert, Jean-Luc; Schwegler, Eric

    2015-09-16

    The focus of this SciDAC SAP (Scientific Application) is the development and use of quantum simulations techniques to understand materials and nanostructures at the microscopic level, predict their physical and chemical properties, and eventually design integrated materials with targeted properties. (Here the word ‘materials’ is used in a broad sense and it encompasses different thermodynamic states of matter, including solid, liquids and nanostructures.) Therefore our overarching goal is to enable scientific discoveries in the field of condensed matter and advanced materials through high performance computing.

  1. Investigation of surface plasmon resonance in composite nanostructure of silver film and nanowire array

    NASA Astrophysics Data System (ADS)

    Li, Jun; Yang, Junyi; Wu, Xingzhi; Song, Yinglin

    2016-10-01

    We investigate the surface plasmon resonance in a new composite nanostructure (Nanowires array beneath metal film). Computational simulation results exhibit that, for both transverse electric(TE) and transverse magnetic (TM) polarization, the positions of resonance peaks is extremely sensitive to the change of center distance (Filling ratio of nanowires). When the diameter of Nanowires is 4nm and under TM polarization, the resonance angle increasing with the increase of center distance. In the case of TE polarization, the result is completely the opposite within limits. It is also shown that changes in thickness of Ag film(At the top of the Ag nanowire) has little direct effect on the resonance angle, But the characteritics of SPR intensity is influenced by the thickness of Ag film in the most degree. When the thickness of Ag film is 50 nm, In range of 10nm to 100nm, the minimum value of the reflectance is only 0.05, the result is consistent with the previous studies. Additionally, the nano composite structure material is very sensitive to the refractive index change of the lowest layer when under the TE- polarization. we have done mode analysis of the SPR structure for both simple and practical structures using comsol multiphysics, our approach is intend to show the feasibity and extend the applicability of the plasmonic nanowires, could lead to provide the basis for design the new structure of nanowires array.

  2. Tuning the composition and nanostructure of Pt/Ir films via anodized aluminum oxide templated atomic layer deposition.

    SciTech Connect

    Comstock, D. J.; Christensen, S. T.; Elam, J. W.; Pellin, M. J.; Hersam, M. C.; Northwestern Univ.

    2010-09-23

    Nanostructured metal films have been widely studied for their roles in sensing, catalysis, and energy storage. In this work, the synthesis of compositionally controlled and nanostructured Pt/Ir films by atomic layer deposition (ALD) into porous anodized aluminum oxide templates is demonstrated. Templated ALD provides advantages over alternative synthesis techniques, including improved film uniformity and conformality as well as atomic-scale control over morphology and composition. Nanostructured Pt ALD films are demonstrated with morphological control provided by the Pt precursor exposure time and the number of ALD cycles. With these approaches, Pt films with enhanced surface areas, as characterized by roughness factors as large as 310, are reproducibly synthesized. Additionally, nanostructured Ptlr alloy films of controlled composition and morphology are demonstrated by templated ALD, with compositions varying systematically from pure Pt to pure Ir. Lastly, the application of nanostructured Pt films to electrochemical sensing applications is demonstrated by the non-enzymatic sensing of glucose.

  3. Nonlinear Dynamic Properties of Layered Composite Materials

    SciTech Connect

    Andrianov, Igor V.; Topol, Heiko; Weichert, Dieter; Danishevs'kyy, Vladyslav V.

    2010-09-30

    We present an application of the asymptotic homogenization method to study wave propagation in a one-dimensional composite material consisting of a matrix material and coated inclusions. Physical nonlinearity is taken into account by considering the composite's components as a Murnaghan material, structural nonlinearity is caused by the bonding condition between the components.

  4. Nanostructured carbon-metal oxide composite electrodes for supercapacitors: a review.

    PubMed

    Zhi, Mingjia; Xiang, Chengcheng; Li, Jiangtian; Li, Ming; Wu, Nianqiang

    2013-01-07

    This paper presents a review of the research progress in the carbon-metal oxide composites for supercapacitor electrodes. In the past decade, various carbon-metal oxide composite electrodes have been developed by integrating metal oxides into different carbon nanostructures including zero-dimensional carbon nanoparticles, one-dimensional nanostructures (carbon nanotubes and carbon nanofibers), two-dimensional nanosheets (graphene and reduced graphene oxides) as well as three-dimensional porous carbon nano-architectures. This paper has described the constituent, the structure and the properties of the carbon-metal oxide composites. An emphasis is placed on the synergistic effects of the composite on the performance of supercapacitors in terms of specific capacitance, energy density, power density, rate capability and cyclic stability. This paper has also discussed the physico-chemical processes such as charge transport, ion diffusion and redox reactions involved in supercapacitors.

  5. A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties.

    PubMed

    Dastjerdi, Roya; Montazer, Majid

    2010-08-01

    Textiles can provide a suitable substrate to grow micro-organisms especially at appropriate humidity and temperature in contact to human body. Recently, increasing public concern about hygiene has been driving many investigations for anti-microbial modification of textiles. However, using many anti-microbial agents has been avoided because of their possible harmful or toxic effects. Application of inorganic nano-particles and their nano-composites would be a good alternative. This review paper has focused on the properties and applications of inorganic nano-structured materials with good anti-microbial activity potential for textile modification. The discussed nano-structured anti-microbial agents include TiO(2) nano-particles, metallic and non-metallic TiO(2) nano-composites, titania nanotubes (TNTs), silver nano-particles, silver-based nano-structured materials, gold nano-particles, zinc oxide nano-particles and nano-rods, copper nano-particles, carbon nanotubes (CNTs), nano-clay and its modified forms, gallium, liposomes loaded nano-particles, metallic and inorganic dendrimers nano-composite, nano-capsules and cyclodextrins containing nano-particles. This review is also concerned with the application methods for the modification of textiles using nano-structured materials.

  6. Modeling Mechanical Properties of Carbon Molecular Clusters and Carbon Nanostructural Materials

    DTIC Science & Technology

    2003-01-01

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP014264 TITLE: Modeling Mechanical Properties of Carbon Molecular...Clusters and Carbon Nanostructural Materials DISTRIBUTION: Approved for public release, distribution unlimited This paper is part of the following report...Res. Soc. Symp. Proc. Vol. 740 © 2003 Materials Research Society 17.2 Modeling mechanical properties of carbon molecular clusters and carbon

  7. Confinement effects on chemical reactions in nanostructured carbon materials

    NASA Astrophysics Data System (ADS)

    George, Aaron; Kostov, Milen; Buongiorno Nardelli, Marco

    2005-03-01

    Chemical reactions are frequently carried out in nano-structured media, such as micellar or colloidal solutions, nano-porous media, hydrogels or organogels, or in systems involving nano-particles. Nanostructured environments have been shown to enhance reaction rates through a variety of catalytic effects, such as high surface area, interactions with the nano-structure or confinement. In this work, we have used state-of-the-art electronic structure techniques to study the prototypical example of the hydrogen-producing reaction of formaldehyde dissociation (H2CO -> H2 + CO) within various configurations of a graphitic pore. Using the Nudged Elastic Band (NEB) method for transition states analysis, we have found that the activation energy of the dissociation can be influenced by the presence of a graphitic pore. In particular, while a graphene surface reduces the activation barrier for the reaction, this catalytic effect is enhanced by the presence of two planar sheets, which mimic the geometry of a nano-pore. These findings will be discussed in terms of the charge transfer and/or polarization mechanism associated with the catalytic process.

  8. Evaluation of antibacterial activity of nanostructured poly(1-naphthylamine) and its composites.

    PubMed

    Riaz, Ufana; Khan, Shahanavaj; Islam, Mohd Nazrul; Ahmad, Sharif; Ashraf, S M

    2008-01-01

    The present study reports some preliminary investigations on the antibacterial activity of nanostructured poly(1-naphthylamine) (PNA) and its composites with polyvinyl alcohol (PVA) and polyvinylchloride (PVC). The antibacterial activity was evaluated against Escherichia coli and Staphylococcus aureus. The particle size and morphology of PNA and its composites was found to play a significant role in deciding the antimicrobial efficiency. A mechanism of antimicrobial activity has been suggested.

  9. Method of making nanopatterns and nanostructures and nanopatterned functional oxide materials

    DOEpatents

    Dravid, Vinayak P; Donthu, Suresh K; Pan, Zixiao

    2014-02-11

    Method for nanopatterning of inorganic materials, such as ceramic (e.g. metal oxide) materials, and organic materials, such as polymer materials, on a variety of substrates to form nanopatterns and/or nanostructures with control of dimensions and location, all without the need for etching the materials and without the need for re-alignment between multiple patterning steps in forming nanostructures, such as heterostructures comprising multiple materials. The method involves patterning a resist-coated substrate using electron beam lithography, removing a portion of the resist to provide a patterned resist-coated substrate, and spin coating the patterned resist-coated substrate with a liquid precursor, such as a sol precursor, of the inorganic or organic material. The remaining resist is removed and the spin coated substrate is heated at an elevated temperature to crystallize the deposited precursor material.

  10. Durability of Composite Materials and Structures

    DTIC Science & Technology

    2009-11-02

    Michigan State University Composite Materials and Structures Center 2100 Engineering Building , East Lansing, MI 48824-1226 6.1 Objectives The...DATES COVERED (From - To) February 7, 2005 - January 31. 2009 4. TITLE AND SUBTITLE DURABILITY OF COMPOSITE MATERIALS AND STRUCTURES 5a...Manager: Dr. Yapa D.S. Rajapakse Office of Naval Research 875 N. Randolph Street Arlington, VA 22203-1995 DURABILITY OF COMPOSITE MATERIALS AND

  11. Method for machining holes in composite materials

    NASA Technical Reports Server (NTRS)

    Daniels, Julia G. (Inventor); Ledbetter, Frank E., III (Inventor); Clemons, Johnny M. (Inventor); Penn, Benjamin G. (Inventor); White, William T. (Inventor)

    1987-01-01

    A method for boring well defined holes in a composite material such as graphite/epoxy is discussed. A slurry of silicon carbide powder and water is projected onto a work area of the composite material in which a hole is to be bored with a conventional drill bit. The silicon carbide powder and water slurry allow the drill bit, while experiencing only normal wear, to bore smooth, cylindrical holes in the composite material.

  12. Process for producing dispersed particulate composite materials

    DOEpatents

    Henager, Jr., Charles H.; Hirth, John P.

    1995-01-01

    This invention is directed to a process for forming noninterwoven dispersed particulate composite products. In one case a composite multi-layer film product comprises a substantially noninterwoven multi-layer film having a plurality of discrete layers. This noninterwoven film comprises at least one discrete layer of a first material and at least one discrete layer of a second material. In another case the first and second materials are blended together with each other. In either case, the first material comprises a metalloid and the second material a metal compound. At least one component of a first material in one discrete layer undergoes a solid state displacement reaction with at least one component of a second material thereby producing the requisite noninterwoven composite film product. Preferably, the first material comprises silicon, the second material comprises Mo.sub.2 C, the third material comprises SiC and the fourth material comprises MoSi.sub.2.

  13. Shape dependence of nonlinear optical behaviors of nanostructured silver and their silica gel glass composites

    SciTech Connect

    Zheng Chan; Du Yuhong; Feng Miao; Zhan Hongbing

    2008-10-06

    Nanostructured Ag in shapes of nanoplate, nanowire, and nanoparticle, as well as their silica gel glass composites have been prepared and characterized. Nonlinear optical (NLO) properties were measured at 532 and 1064 nm using open aperture z-scan technique and studied from the view of shape effect. NLO behaviors of the nanostructured Ag are found to be shape dependent in suspensions at both the investigated wavelengths, although they originate differently. Comparing to the mother suspensions, the Ag/silica gel glass nanocomposites present rather dissimilar NLO behaviors, which is quite interesting for further studies.

  14. NASA technology utilization survey on composite materials

    NASA Technical Reports Server (NTRS)

    Leeds, M. A.; Schwartz, S.; Holm, G. J.; Krainess, A. M.; Wykes, D. M.; Delzell, M. T.; Veazie, W. H., Jr.

    1972-01-01

    NASA and NASA-funded contractor contributions to the field of composite materials are surveyed. Existing and potential non-aerospace applications of the newer composite materials are emphasized. Economic factors for selection of a composite for a particular application are weight savings, performance (high strength, high elastic modulus, low coefficient of expansion, heat resistance, corrosion resistance,), longer service life, and reduced maintenance. Applications for composites in agriculture, chemical and petrochemical industries, construction, consumer goods, machinery, power generation and distribution, transportation, biomedicine, and safety are presented. With the continuing trend toward further cost reductions, composites warrant consideration in a wide range of non-aerospace applications. Composite materials discussed include filamentary reinforced materials, laminates, multiphase alloys, solid multiphase lubricants, and multiphase ceramics. New processes developed to aid in fabrication of composites are given.

  15. Composite materials for battery applications

    DOEpatents

    Amine, Khalil; Yang, Junbing; Abouimrane, Ali; Ren, Jianguo

    2017-03-14

    A process for producing nanocomposite materials for use in batteries includes electroactive materials are incorporated within a nanosheet host material. The process may include treatment at high temperatures and doping to obtain desirable properties.

  16. Nanostructured materials detect epidermal growth factor receptor, neuron specific enolase and carcinoembryonic antigen

    NASA Astrophysics Data System (ADS)

    Stefan-van Staden, Raluca-Ioana; Comnea-Stancu, Ionela Raluca; Surdu-Bob, Carmen Cristina; Badulescu, Marius

    2015-09-01

    New nanostructured materials based on thin films of Cu and Ni deposited on textile material (veil), as well as gold nanostructured microspheres were used for the design of new stochastic sensors. The stochastic sensors were able to detect simultaneously a panel of biomarkers comprising epidermal growth factor receptor, neuron specific enolase, and carcinoembryonic antigen from whole blood samples with high reliabilities - recovery tests higher than 97.00%, with a RSD (%) lower than 0.1%. The stochastic sensors had shown high sensitivities and low determination levels for the detection of the proposed panel of biomarkers making early detection of lung cancer possible by fast screening of whole blood.

  17. Composite structural materials. [fiber reinforced composites for aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

    1981-01-01

    Physical properties of fiber reinforced composites; structural concepts and analysis; manufacturing; reliability; and life prediction are subjects of research conducted to determine the long term integrity of composite aircraft structures under conditions pertinent to service use. Progress is reported in (1) characterizing homogeneity in composite materials; (2) developing methods for analyzing composite materials; (3) studying fatigue in composite materials; (4) determining the temperature and moisture effects on the mechanical properties of laminates; (5) numerically analyzing moisture effects; (6) numerically analyzing the micromechanics of composite fracture; (7) constructing the 727 elevator attachment rib; (8) developing the L-1011 engine drag strut (CAPCOMP 2 program); (9) analyzing mechanical joints in composites; (10) developing computer software; and (11) processing science and technology, with emphasis on the sailplane project.

  18. Emerging Prototype Sodium-Ion Full Cells with Nanostructured Electrode Materials.

    PubMed

    Ren, Wenhao; Zhu, Zixuan; An, Qinyou; Mai, Liqiang

    2017-04-10

    Due to steadily increasing energy consumption, the demand of renewable energy sources is more urgent than ever. Sodium-ion batteries (SIBs) have emerged as a cost-effective alternative because of the earth abundance of Na resources and their competitive electrochemical behaviors. Before practical application, it is essential to establish a bridge between the sodium half-cell and the commercial battery from a full cell perspective. An overview of the major challenges, most recent advances, and outlooks of non-aqueous and aqueous sodium-ion full cells (SIFCs) is presented. Considering the intimate relationship between SIFCs and electrode materials, including structure, composition and mutual matching principle, both the advance of various prototype SIFCs and the electrochemistry development of nanostructured electrode materials are reviewed. It is noted that a series of SIFCs combined with layered oxides and hard carbon are capable of providing a high specific gravimetric energy above 200 Wh kg(-1) , and an NaCrO2 //hard carbon full cell is able to deliver a high rate capability over 100 C. To achieve industrialization of SIBs, more systematic work should focus on electrode construction, component compatibility, and battery technologies.

  19. Nanostructured multilayered thin film barriers for Mg{sub 2}Si thermoelectric materials

    SciTech Connect

    Battiston, S.; Boldrini, S.; Fiameni, S.; Agresti, F.; Famengo, A.; Fabrizio, M.; Barison, S.

    2012-06-26

    The Mg{sub 2}Si-based alloys are promising candidates for thermoelectric energy conversion in the middle-high temperature range in order to replace lead compounds. The main advantages of silicide-based thermoelectrics are the nontoxicity and the abundance of their constituent elements in the earth crust. The drawback of such kind of materials is their oxygen sensitivity at high temperature that entails their use under vacuum or inert atmosphere. In order to limit the corrosion phenomena, nanostructured multilayered molybdenum silicide-based materials were deposited via RF magnetron sputtering onto stainless steel, alumina and silicon (100) to set up the deposition process and then onto Mg{sub 2}Si pellets. XRD, EDS, FE-SEM and electrical measurements at high temperature were carried out in order to obtain, respectively, the structural, compositional, morphological and electrical characterization of the deposited coatings. At the end, the mechanical behavior of the system thin film/Mg{sub 2}Si-substrate as a function of temperature and the barrier properties for oxygen protection after thermal treatment in air at high temperature were qualitatively evaluated by FE-SEM.

  20. Synthesis and Electron Field-Emission of 1-D Carbon-Related Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Shih, Han C.

    2002-10-01

    field emission characteristics of the 1-D carbon-related nanostructures were measured by the conventional diode method at an ambient pressure of 1.3X10-3 Pa (10-5 Torr). The films (1X1-cm^2) were separated from the anode by ITO (indium tin oxide) coated glass, where a glass fiber spacer was maintained at 150 μm from the cathode. The current density and electric field characteristics were measured using a Keithley 237 electrometer. A range of onset electron emission field from 3.5 to 1.5 V/μm and an emission current density up to 1 mA/cm^2 at 3V/μm have been achieved in this study, apparently superior to other carbon-based electron field emitters[3]. The results were reproducible over a period of weeks and the nanotubes did not degrade physically when exposing to a humid air of RH 90using the Fowler-Nordheim model, I=aV^2 exp (-bΦ_e^3/2/V) , where a and b are constants. The turn-on voltage was estimated as the voltage deviating from ln(I/V^2)-1/V curve. The effective work function (Φ_e=Φ/β) of the arrayed carbon nanotubes was calculated from the slope of the Fowler-Nordheim plot, where the value of β, the field enhancement factor, was found to be 1517. This value increased to 3357 when nitrogen was doped, but decreased to 974 when boron was doped. The incorporation of nitrogen or boron into the carbon network apparently changes the original nanostructure and the chemical bonding. The structural and compositional modification by the incorporation of nitrogen, boron, or hydrogen into the 1-D carbon-related nanostructured materials were analyzed by FTIR , XPS , Raman spectroscopy , and FE-SEM . Various forms in connection with 1-D nanostructured materials applicable to the NEMS , e.g. , nanowelding of nanotubes[4], tubes on tube , open-end nanotubes and coils of nanofiber and nanotubes have been produced in this research depending on the plasma chemistry, catalytic effect and the design of template. [1]. S. Iijima, Nature 354, 56 (1991). [2]. S. L. Sung, S. H. Tsai

  1. Zinc-oxide-based nanostructured materials for heterostructure solar cells

    SciTech Connect

    Bobkov, A. A.; Maximov, A. I.; Moshnikov, V. A. Somov, P. A.; Terukov, E. I.

    2015-10-15

    Results obtained in the deposition of nanostructured zinc-oxide layers by hydrothermal synthesis as the basic method are presented. The possibility of controlling the structure and morphology of the layers is demonstrated. The important role of the procedure employed to form the nucleating layer is noted. The faceted hexagonal nanoprisms obtained are promising for the fabrication of solar cells based on oxide heterostructures, and aluminum-doped zinc-oxide layers with petal morphology, for the deposition of an antireflection layer. The results are compatible and promising for application in flexible electronics.

  2. Self-Assembly and Headgroup Effect in Nanostructured Organogels via Cationic Amphiphile-Graphene Oxide Composites

    PubMed Central

    Jiao, Tifeng; Wang, Yujin; Zhang, Qingrui; Yan, Xuehai; Zhao, Xiaoqing; Zhou, Jingxin; Gao, Faming

    2014-01-01

    Self-assembly of hierarchical graphene oxide (GO)-based nanomaterials with novel functions has received a great deal of attentions. In this study, nanostructured organogels based on cationic amphiphile-GO composites were prepared. The gelation behaviors of amphiphile-GO composites in organic solvents can be regulated by changing the headgroups of amphiphiles. Ammonium substituted headgroup in molecular structures in present self-assembled composites is more favorable for the gelation in comparison to pyridinium headgroup. A possible mechanism for headgroup effects on self-assembly and as-prepared nanostructures is proposed. It is believed that the present amphiphile-GO self-assembled system will provide an alternative platform for the design of new GO nanomaterials and soft matters. PMID:24983466

  3. Distribution patterns of different carbon nanostructures in silicon nitride composites.

    PubMed

    Tapasztó, Orsolya; Markó, Márton; Balázsi, Csaba

    2012-11-01

    The dispersion properties of single- and multi-walled carbon nanotubes as well as mechanically exfoliated few layer graphene flakes within the silicon nitride ceramic matrix have been investigated. Small angle neutron scattering experiments have been employed to gain information on the dispersion of the nano-scale carbon fillers throughout the entire volume of the samples. The neutron scattering data combined with scanning electron microscopy revealed strikingly different distribution patterns for different types of carbon nanostructures. The scattering intensities for single wall carbon nanotubes (SWCNTs) reveal a decay exponent characteristic to surface fractals, which indicate that the predominant part of nanotubes can be found in loose networks wrapping the grains of the polycrystalline matrix. By contrast, multi wall carbon nanotubes (MWCNTs) were found to be present mainly in the form of bulk aggregate structures, while few-layer graphene (FLG) flakes have been individually dispersed within the host matrix, under the very same preparation and processing conditions.

  4. Microstructure and mechanical properties of 7075 aluminum alloy nanostructured composites processed by mechanical milling and indirect hot extrusion

    SciTech Connect

    Flores-Campos, R.; Estrada-Guel, I.; Miki-Yoshida, M.; Martinez-Sanchez, R.; Herrera-Ramirez, J.M.

    2012-01-15

    Nanostructured composites of 7075 aluminum alloy and carbon coated silver nanoparticles were produced by mechanical milling and indirect hot extrusion. The milling products were obtained in a high energy SPEX ball mill, and then were compacted by uniaxial load and pressure-less sintered under argon atmosphere. Finally, the sintered product was hot extruded. Carbon coated silver nanoparticles were well distributed in the matrix of the extruded material. Tensile tests were carried out to corroborate the hypothesis that second phase particles, well dispersed in the matrix, improve the strength of the material. High resolution transmission electron microscopy was employed to locate and make sure that the silver nanoparticles were homogeneously and finely dispersed. Highlights: Black-Right-Pointing-Pointer 7075 Al nanostructured composites can be produced by mechanical milling. Black-Right-Pointing-Pointer Carbon coated silver nanoparticles are well dispersed into aluminum matrix. Black-Right-Pointing-Pointer Ductile Ag-C NP's improve the mechanical properties of the 7075 Al-alloy. Black-Right-Pointing-Pointer Ag-C NP's content has an important effect in the particle and crystallite size. Black-Right-Pointing-Pointer Ag-C NP's keep their morphology after milling and conformation processes.

  5. Nanostructured TiOx as a catalyst support material for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Phillips, Richard S.

    Recent interest in the development of new catalyst support materials for proton exchange membrane fuel cells (PEMFCs) has stimulated research into the viability of TiO2-based support structures. Specifically, substoichiometric TiO2 (TiOx) has been reported to exhibit a combination of high conductivity, stability, and corrosion resistance. These properties make TiOx-based support materials a promising prospect when considering the inferior corrosion resistance of traditional carbon-based supports. This document presents an investigation into the formation of conductive and stable TiOx thin films employing atomic layer deposition (ALD) and a post deposition oxygen reducing anneal (PDORA). Techniques for manufacturing TiOx-based catalyst support nanostructures by means of ALD in conjunction with carbon black (CB), anodic aluminum oxide (AAO) and silicon nanowires (SiNWs) will also be presented. The composition and thickness of resulting TiOx thin films was determined with the aid of Auger electron spectroscopy (AES), Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). Film crystal structure was determined with X-ray diffraction (XRD) analysis. Film conductivity was calculated using four-point probe (4-PP) and film thickness measurement data. Resulting thin films show a significant decrease of oxygen in ALD TiOx films corresponding with a great increase in conductivity following the PDORA. The effectiveness of the PDORA was also found to be highly dependent on ALD process parameters. TiOx-based nanostructures were coated with platinum using one of three Pt deposition techniques. First, liquid phase deposition (LPD), which was performed at room temperature, provided equal access to catalyst support material surfaces which were suspended in solution. Second, plasma enhanced atomic layer deposition (PEALD), which was performed at 450°C, provided good Pt

  6. Clues for biomimetics from natural composite materials

    PubMed Central

    Lapidot, Shaul; Meirovitch, Sigal; Sharon, Sigal; Heyman, Arnon; Kaplan, David L; Shoseyov, Oded

    2013-01-01

    Bio-inspired material systems are derived from different living organisms such as plants, arthropods, mammals and marine organisms. These biomaterial systems from nature are always present in the form of composites, with molecular-scale interactions optimized to direct functional features. With interest in replacing synthetic materials with natural materials due to biocompatibility, sustainability and green chemistry issues, it is important to understand the molecular structure and chemistry of the raw component materials to also learn from their natural engineering, interfaces and interactions leading to durable and highly functional material architectures. This review will focus on applications of biomaterials in single material forms, as well as biomimetic composites inspired by natural organizational features. Examples of different natural composite systems will be described, followed by implementation of the principles underlying their composite organization into artificial bio-inspired systems for materials with new functional features for future medicine. PMID:22994958

  7. Green energy storage materials: advanced nanostructured materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Tripathi, Alok Mani; Chandrasekar, M. S.; Mitra, Sagar

    2011-06-01

    The projected doubling of world energy consumption in the next fifty years requires certain measures to meet this demand. The ideal energy provider is reliable, efficient, with low emissions source - wind, solar, etc. The low carbon footprint of renewables is an added benefit, which makes them especially attractive during this era of environmental consciousness. Unfortunately, the intermittent nature of energy from these renewables is not suitable for the commercial and residential grid application, unless the power delivery is 24/7, with minimum fluctuation. This requires intervention of efficient electrical energy storage technology to make power generation from renewable practical. The progress to higher energy and power density especially for battery technology will push material to the edge of stability and yet these materials must be rendered safe, stable and with reliable operation throughout their long life. A major challenge for chemical energy storage is developing the ability to store more energy while maintaining stable electrode-electrolyte interface. A structural transformation occurs during charge-discharge cycle, accompanied by a volume change, degrading the microstructure over-time. The need to mitigate this volume and structural change accompanying charge-discharge cycle necessitates going to nanostructured and multifunctional materials that have the potential of dramatically enhancing the energy density and power density.

  8. Composite materials and method of making

    DOEpatents

    Simmons, Kevin L [Kennewick, WA; Wood, Geoffrey M [North Saanich, CA

    2011-05-17

    A method for forming improved composite materials using a thermosetting polyester urethane hybrid resin, a closed cavity mold having an internal heat transfer mechanism used in this method, and the composite materials formed by this method having a hybrid of a carbon fiber layer and a fiberglass layer.

  9. Nickel Based Electrospun Materials with Tuned Morphology and Composition

    PubMed Central

    Ercolano, Giorgio; Farina, Filippo; Cavaliere, Sara; Jones, Deborah J.; Rozière, Jacques

    2016-01-01

    Nickel is set to play a crucial role to substitute the less-abundant platinum in clean electrochemical energy conversion and storage devices and catalysis. The controlled design of Ni nanomaterials is essential to fine-tune their properties to match these applications. A systematic study of electrospinning and thermal post-treatment parameters has been performed to synthesize Ni materials and tune their morphology (fibers, ribbons, and sponge-like structures) and composition (metallic Ni, NiO, Ni/C, Ni3N and their combinations). The obtained Ni-based spun materials have been characterized by scanning and transmission electron microscopy, X-ray diffraction and thermogravimetric analysis. The possibility of upscaling and the versatility of electrospinning open the way to large-scale production of Ni nanostructures, as well as bi- and multi-metal systems for widened applications. PMID:28335364

  10. Composite Dielectric Materials for Electrical Switching

    SciTech Connect

    Modine, F.A.

    1999-04-25

    Composites that consist of a dielectric host containing a particulate conductor as a second phase are of interest for electrical switching applications. Such composites are "smart" materials that can function as either voltage or current limiters, and the difference in fimction depends largely upon whether the dielectric is filled to below or above the percolation threshold. It also is possible to combine current and voltage limiting in a single composite to make a "super-smart" material.

  11. Nonlinear optical switch creation on the base of step change refractive index of nanostructure materials

    NASA Astrophysics Data System (ADS)

    Salikhov, Aydar I.; Sultanov, Albert H.; Vinogradova, Irina L.

    2008-12-01

    Optical characteristics of materials being in nanostructure condition are described. Possible versions of use of the detected spasmodic variation of a parameter of refraction of new materials are offered. The method of construction high-speed the optical switch, operated by variation of a parameter of refraction of a transparent optical material by means of additional radiation, or variation of parameters of the transferred signal is developed, allowing to make switching in time, compared in due course relaxations of substance.

  12. Effect of Interface Structure on Mechanical Properties of Advanced Composite Materials

    PubMed Central

    Gan, Yong X.

    2009-01-01

    This paper deals with the effect of interface structures on the mechanical properties of fiber reinforced composite materials. First, the background of research, development and applications on hybrid composite materials is introduced. Second, metal/polymer composite bonded structures are discussed. Then, the rationale is given for nanostructuring the interface in composite materials and structures by introducing nanoscale features such as nanopores and nanofibers. The effects of modifying matrices and nano-architecturing interfaces on the mechanical properties of nanocomposite materials are examined. A nonlinear damage model for characterizing the deformation behavior of polymeric nanocomposites is presented and the application of this model to carbon nanotube-reinforced and reactive graphite nanotube-reinforced epoxy composite materials is shown. PMID:20054466

  13. Effect of interface structure on mechanical properties of advanced composite materials.

    PubMed

    Gan, Yong X

    2009-11-25

    This paper deals with the effect of interface structures on the mechanical properties of fiber reinforced composite materials. First, the background of research, development and applications on hybrid composite materials is introduced. Second, metal/polymer composite bonded structures are discussed. Then, the rationale is given for nanostructuring the interface in composite materials and structures by introducing nanoscale features such as nanopores and nanofibers. The effects of modifying matrices and nano-architecturing interfaces on the mechanical properties of nanocomposite materials are examined. A nonlinear damage model for characterizing the deformation behavior of polymeric nanocomposites is presented and the application of this model to carbon nanotube-reinforced and reactive graphite nanotube-reinforced epoxy composite materials is shown.

  14. The influence of reinforcement size on the microstructure and mechanical behavior of a nanostructured aluminum-based metal matrix composite

    NASA Astrophysics Data System (ADS)

    Behm, Nathan Adam

    With increased availability and growing commercial applications, aluminum-based metal matrix composites show promise as high specific strength structural materials. Before they can be implemented however, they require thorough characterization and testing. A novel nanostructured aluminum-based metal matrix composite (MMC) was characterized through a combination of microstructural analysis and mechanical testing. Two composites were studied, an aluminum MMC reinforced with 50 nm boron carbide, (B4C) and an aluminum MMC reinforced with 500 nm boron carbide. Transmission electron microscopy (TEM) analysis revealed an ultra-fine grained matrix with grains on the order of 100--300 nm. The quasi-static and dynamic response of the composites was compared with the behavior of the unreinforced aluminum alloy, and it was found that the reinforcement resulted in a 30% improvement in strength. The decrease in the reinforcement size from 500 to 50 nm activated an additional strengthening mechanism, which further improved the strength of the MMC reinforced with the 50 nm B4C. Dynamic compression tests were performed at elevated temperatures up 400°C on the composites, and it was found that they exhibited impressive strengths considering the thermal softening prevalent in aluminum. The reinforcement size was found to play an important role in the strain softening exhibited at elevated temperature, fracture mechanism, and composite strength. Models to describe the composite behavior are presented.

  15. Reduction of thermal conductivity of bulk nanostructured bismuth telluride composites embedded with silicon nano-inclusions

    NASA Astrophysics Data System (ADS)

    Satyala, Nikhil; Tahmasbi Rad, Armin; Zamanipour, Zahra; Norouzzadeh, Payam; Krasinski, Jerzy S.; Tayebi, Lobat; Vashaee, Daryoosh

    2014-01-01

    Bulk nanostructured bismuth telluride (Bi2Te3) composite with silicon nano-crystallite inclusions was synthesized via sintering approach. The effect of the composite structure formed by the addition of miniscule quantity (5 at. %) of silicon on the thermoelectric properties of bulk nanostructured Bi2Te3 is shown via a 50% drop in thermal conductivity accompanied with a simultaneous enhancement in the Seebeck coefficient. We demonstrate that the addition of silicon nano-inclusions to the nanostructured compound combined with a systematic thermal treatment beneficially reduces the thermal conductivity to less than 1.0 W/mK over the entire temperature range of 300 K to 525 K. It is shown that the combinatorial techniques of nanostructuring, nano-inclusions, and annealing are effective in reducing thermal conductivity by a significant magnitude. This low thermal conductivity is comparable to that of Bi2Te3 based superlattices and significantly lower than that of bulk Bi2Te3. The technique is extendable to (Bi,Se)2(Sb,Te)3 based thermoelectric alloys for enhancing the figure-of-merit.

  16. Composites and blends from biobased materials

    SciTech Connect

    Kelley, S.S.

    1995-05-01

    The program is focused on the development of composites and blends from biobased materials to use as membranes, high value plastics, and lightweight composites. Biobased materials include: cellulose derivative microporous materials, cellulose derivative copolymers, and cellulose derivative blends. This year`s research focused on developing an improved understanding of the molecular features that cellulose based materials with improved properties for gas separation applications. Novel cellulose ester membrane composites have been developed and are being evaluated under a collaborative research agreement with Dow Chemicals Company.

  17. Composite materials for biomedical applications: a review.

    PubMed

    Salernitano, E; Migliaresi, C

    2003-01-01

    The word "composite" refers to the combination, on a macroscopic scale, of two or more materials, different for composition, morphology and general physical properties. In many cases, and depending on the constituent properties, composites can be designed with a view to produce materials with properties tailored to fulfill specific chemical, physical or mechanical requirements. Therefore over the past 40 years the use of composites has progressively increased, and today composite materials have many different applications, i.e., aeronautic, automotive, naval, and so on. Consequently many composite biomaterials have recently been studied and tested for medical application. Some of them are currently commercialized for their advantages over traditional materials. Most human tissues such as bones, tendons, skin, ligaments, teeth, etc., are composites, made up of single constituents whose amount, distribution, morphology and properties determine the final behavior of the resulting tissue or organ. Man-made composites can, to some extent, be used to make prostheses able to mimic these biological tissues, to match their mechanical behavior and to restore the mechanical functions of the damaged tissue. Different types of composites that are already in use or are being investigated for various biomedical applications are presented in this paper. Specific advantages and critical issues of using composite biomaterials are also described (Journal of Applied Bio-materials & Biomechanics 2003; 1: 3-18).

  18. Strong, ductile, and thermally stable Cu-based metal-intermetallic nanostructured composites

    NASA Astrophysics Data System (ADS)

    Dusoe, Keith J.; Vijayan, Sriram; Bissell, Thomas R.; Chen, Jie; Morley, Jack E.; Valencia, Leopolodo; Dongare, Avinash M.; Aindow, Mark; Lee, Seok-Woo

    2017-01-01

    Bulk metallic glasses (BMGs) and nanocrystalline metals (NMs) have been extensively investigated due to their superior strengths and elastic limits. Despite these excellent mechanical properties, low ductility at room temperature and poor microstructural stability at elevated temperatures often limit their practical applications. Thus, there is a need for a metallic material system that can overcome these performance limits of BMGs and NMs. Here, we present novel Cu-based metal-intermetallic nanostructured composites (MINCs), which exhibit high ultimate compressive strengths (over 2 GPa), high compressive failure strain (over 20%), and superior microstructural stability even at temperatures above the glass transition temperature of Cu-based BMGs. Rapid solidification produces a unique ultra-fine microstructure that contains a large volume fraction of Cu5Zr superlattice intermetallic compound; this contributes to the high strength and superior thermal stability. Mechanical and microstructural characterizations reveal that substantial accumulation of phase boundary sliding at metal/intermetallic interfaces accounts for the extensive ductility observed.

  19. Strong, ductile, and thermally stable Cu-based metal-intermetallic nanostructured composites

    PubMed Central

    Dusoe, Keith J.; Vijayan, Sriram; Bissell, Thomas R.; Chen, Jie; Morley, Jack E.; Valencia, Leopolodo; Dongare, Avinash M.; Aindow, Mark; Lee, Seok-Woo

    2017-01-01

    Bulk metallic glasses (BMGs) and nanocrystalline metals (NMs) have been extensively investigated due to their superior strengths and elastic limits. Despite these excellent mechanical properties, low ductility at room temperature and poor microstructural stability at elevated temperatures often limit their practical applications. Thus, there is a need for a metallic material system that can overcome these performance limits of BMGs and NMs. Here, we present novel Cu-based metal-intermetallic nanostructured composites (MINCs), which exhibit high ultimate compressive strengths (over 2 GPa), high compressive failure strain (over 20%), and superior microstructural stability even at temperatures above the glass transition temperature of Cu-based BMGs. Rapid solidification produces a unique ultra-fine microstructure that contains a large volume fraction of Cu5Zr superlattice intermetallic compound; this contributes to the high strength and superior thermal stability. Mechanical and microstructural characterizations reveal that substantial accumulation of phase boundary sliding at metal/intermetallic interfaces accounts for the extensive ductility observed. PMID:28067334

  20. Nanostructured composites obtained by ATRP sleeving of bacterial cellulose nanofibers with acrylate polymers.

    PubMed

    Lacerda, Paula S S; Barros-Timmons, Ana M M V; Freire, Carmen S R; Silvestre, Armando J D; Neto, Carlos P

    2013-06-10

    Novel nanostructured composite materials based on bacterial cellulose membranes (BC) and acrylate polymers were prepared by in situ atom transfer radical polymerization (ATRP). BC membranes were functionalized with initiating sites, by reaction with 2-bromoisobutyryl bromide (BiBBr), followed by atom transfer radical polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA), catalyzed by copper(I) bromide and N,N,N',N″,N″-pentamethyldiethylenetriamine (PMDETA), using two distinct initiator amounts and monomer feeds. The living characteristic of the system was proven by the growth of PBA block from the BC-g-PMMA membrane. The BC nanofiber sleeving was clearly demonstrated by SEM imaging, and its extent can be tuned by controlling the amount of initiating sites and the monomer feed. The ensuing nanocomposites showed high hydrophobicity (contact angles with water up to 134°), good thermal stability (initial degradation temperature in the range 241-275 °C), and were more flexible that the unmodified BC membranes.

  1. Flame-retardant composite materials

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius A.

    1991-01-01

    The properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement are described. The resin matrices included: VPSP/BMI, a blend of vinylpolystyryl pyridine and bismaleimide; BMI, a bismaleimide; and phenolic and PSP, a polystyryl pyridine. The graphite fiber used was AS-4 in the form of either tape or fabric. The properties of these composites were compared with epoxy composites. It was determined that VPSP/BMI with the graphite tape was the optimum design giving the lowest heat release rate.

  2. The Interaction of Bacteria with Engineered Nanostructured Polymeric Materials: A Review

    PubMed Central

    Armentano, Ilaria; Arciola, Carla Renata; Fortunati, Elena; Ferrari, Davide; Mattioli, Samantha; Amoroso, Concetta Floriana; Rizzo, Jessica; Kenny, Jose M.; Imbriani, Marcello; Visai, Livia

    2014-01-01

    Bacterial infections are a leading cause of morbidity and mortality worldwide. In spite of great advances in biomaterials research and development, a significant proportion of medical devices undergo bacterial colonization and become the target of an implant-related infection. We present a review of the two major classes of antibacterial nanostructured materials: polymeric nanocomposites and surface-engineered materials. The paper describes antibacterial effects due to the induced material properties, along with the principles of bacterial adhesion and the biofilm formation process. Methods for antimicrobial modifications of polymers using a nanocomposite approach as well as surface modification procedures are surveyed and discussed, followed by a concise examination of techniques used in estimating bacteria/material interactions. Finally, we present an outline of future sceneries and perspectives on antibacterial applications of nanostructured materials to resist or counteract implant infections. PMID:25025086

  3. Novel applications exploiting the thermal properties of nanostructured materials.

    SciTech Connect

    Eastman, J. A.

    1998-11-20

    A new class of heat transfer fluids, termed nanofluids, has been developed by suspending nanocrystalline particles in liquids. Due to the orders-of-magnitude larger thermal conductivities of solids compared to those of liquids such as water, significantly enhanced thermal properties are obtained with nanofluids. The use of nanofluids could impact many industrial sectors, including transportation, energy supply and production, electronics, textiles, and paper production by, for example, decreasing pumping power needs or reducing heat exchanger sizes. In contrast to the enhancement in effective thermal transport rates that is obtained when nanoparticles are suspended in fluids, nanocrystalline coatings are expected to exhibit reduced thermal conductivities compared to coarse-grained coatings. Reduced thermal conductivities are predicted to arise because of a reduction in the mean free path of phonons due to presence of grain boundaries. This behavior, combined with improved mechanical properties, makes nanostructured zirconia coatings excellent candidates for future applications as thermal barriers.

  4. New textile composite materials development, production, application

    NASA Technical Reports Server (NTRS)

    Mikhailov, Petr Y.

    1993-01-01

    New textile composite materials development, production, and application are discussed. Topics covered include: super-high-strength, super-high-modulus fibers, filaments, and materials manufactured on their basis; heat-resistant and nonflammable fibers, filaments, and textile fabrics; fibers and textile fabrics based on fluorocarbon poylmers; antifriction textile fabrics based on polyfen filaments; development of new types of textile combines and composite materials; and carbon filament-based fabrics.

  5. Polymer Matrix Composite Material Oxygen Compatibility

    NASA Technical Reports Server (NTRS)

    Owens, Tom

    2001-01-01

    Carbon fiber/polymer matrix composite materials look promising as a material to construct liquid oxygen (LOX) tanks. Based on mechanical impact tests the risk will be greater than aluminum, however, the risk can probably be managed to an acceptable level. Proper tank design and operation can minimize risk. A risk assessment (hazard analysis) will be used to determine the overall acceptability for using polymer matrix composite materials.

  6. Composite Materials for Low-Temperature Applications

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Composite materials with improved thermal conductivity and good mechanical strength properties should allow for the design and construction of more thermally efficient components (such as pipes and valves) for use in fluid-processing systems. These materials should have wide application in any number of systems, including ground support equipment (GSE), lunar systems, and flight hardware that need reduced heat transfer. Researchers from the Polymer Science and Technology Laboratory and the Cryogenics Laboratory at Kennedy Space Center were able to develop a new series of composite materials that can meet NASA's needs for lightweight materials/composites for use in fluid systems and also expand the plastic-additive markets. With respect to thermal conductivity and physical properties, these materials are excellent alternatives to prior composite materials and can be used in the aerospace, automotive, military, electronics, food-packaging, and textile markets. One specific application of the polymeric composition is for use in tanks, pipes, valves, structural supports, and components for hot or cold fluid-processing systems where heat flow through materials is a problem to be avoided. These materials can also substitute for metals in cryogenic and other low-temperature applications. These organic/inorganic polymeric composite materials were invented with significant reduction in heat transfer properties. Decreases of 20 to 50 percent in thermal conductivity versus that of the unmodified polymer matrix were measured. These novel composite materials also maintain mechanical properties of the unmodified polymer matrix. These composite materials consist of an inorganic additive combined with a thermoplastic polymer material. The intrinsic, low thermal conductivity of the additive is imparted into the thermoplastic, resulting in a significant reduction in heat transfer over that of the base polymer itself, yet maintaining most of the polymer's original properties. Normal

  7. Fabrication and SERS properties of Ag/Cu2S composite micro-nanostructures over Cu foil.

    PubMed

    Song, Wei; Wang, Jinjie; Mao, Zhu; Xu, Weiqing; Zhao, Bing

    2011-09-01

    A new kind of Ag/Cu2S composite micro/nanostructures has been prepared via a convenient galvanic reduction method. SEM images of these micro/nanostructures showed that Ag nanoparticles with the size of around 50-100 nm were well deposited on the surface of Cu2S micro/nanostructures. The SEM images also indicated that the Ag nanoparticles were preferentially grown on the big polygonal Cu2S microstructures, which could be explained by a localization of the electrons on the surface of the polygonal Cu2S microstructures after the electron transfer step. Owing to the introduction of Ag nanoparticles on the surface of Cu2S micro/nanostructures, the resulting Ag/Cu2S composite micro-nanostructures could be used as a versatile substrate for surface enhanced Raman scattering.

  8. Wear behavior of light-cured resin composites with bimodal silica nanostructures as fillers.

    PubMed

    Wang, Ruili; Bao, Shuang; Liu, Fengwei; Jiang, Xiaoze; Zhang, Qinghong; Sun, Bin; Zhu, Meifang

    2013-12-01

    To enhance wear behavior of resin composites, bimodal silica nanostructures including silica nanoparticles and silica nanoclusters were prepared and proposed as fillers. The silica nanoclusters, a combination of individually dispersed silica nanoparticles and their agglomerations, with size distribution of 0.07-2.70 μm, were fabricated by the coupling reaction between amino and epoxy functionalized silica nanoparticles, which were obtained by the surface modification of silica nanoparticles (~70 nm) using 3-aminopropyl triethoxysilane (APTES) and 3-glycidoxypropyl trimethoxysilane (GPS) as coupling agents, respectively. Silica nanoparticles and nanoclusters were then silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) to prepare composites by mixing with bisphenol A glycerolate dimethacrylate (Bis-GMA) and tri (ethylene glycol) dimethacrylate (TEGDMA). Experimental composites with various filler compositions were prepared and their wear behaviors were assessed in this work. The results suggested that composites with increasing addition of silica nanoparticles in co-fillers possessed lower wear volume and smoother worn surface. Particularly, the composite 53:17 with the optimum weight ratio of silica nanoparticles and silica nanoclusters presented the excellent wear behavior with respect to that of the commercial Esthet-X, although the smallest wear volume was achieved by Z350 XT. The introduction of bimodal silica nanostructures as fillers might provide a new sight for the design of resin composites with significantly improved wear resistance.

  9. Materials research at Stanford University. [composite materials, crystal structure, acoustics

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Research activity related to the science of materials is described. The following areas are included: elastic and thermal properties of composite materials, acoustic waves and devices, amorphous materials, crystal structure, synthesis of metal-metal bonds, interactions of solids with solutions, electrochemistry, fatigue damage, superconductivity and molecular physics and phase transition kinetics.

  10. Carbon nanostructured materials for applications in nano-medicine, cultural heritage, and electrochemical biosensors.

    PubMed

    Valentini, F; Carbone, M; Palleschi, G

    2013-01-01

    This review covers applications of pristine and functionalized single-wall carbon nanotubes (SWCNTs) in nano-medicine, cultural heritage, and biosensors. The physicochemical properties of these engineered nanoparticles are similar to those of ultrafine components of airborne pollution (UF) and might have similar adverse effects. UF may impair cardiovascular autonomic control (inducing a high-risk condition for adverse cardiovascular effects), cause mammalian embryo toxicity, and increase geno-cytotoxic risk. SWCNTs coated with a biopolymer, for example polyethylenimine (PEI), become extremely biocompatible, hence are useful for in-vivo and in-vitro drug delivery and gene transfection. It is also possible to successfully immobilize a human enteric virus on PEI/SWCNT composites, suggesting application as a carrier in non-permissive media. The effectiveness of carbon nanostructured materials in the cleaning, restoration, and consolidation of deteriorated historical surfaces has been widely shown by the use of carbon nanomicelles to remove black dendritic crust from stone surfaces. The nanomicelles, here, have the twofold role of delivery and controlled release of the cleaning agents. The high biocompatibility of functionalized SWCNTs with enzymes and proteins is a fundamental feature used in the assembly of electrochemical biosensors. In particular, a third-generation protoporphyrin IX-based biosensor has been assembled for amperometric detection of nitrite, an environmental pollutant involved in the biodeterioration and black encrustation of historical surfaces.

  11. Composite block copolymer stabilized nanoparticles: simultaneous encapsulation of organic actives and inorganic nanostructures.

    PubMed

    Gindy, Marian E; Panagiotopoulos, Athanassios Z; Prud'homme, Robert K

    2008-01-01

    We describe the preparation and characterization of hybrid block copolymer nanoparticles (NPs) for use as multimodal carriers for drugs and imaging agents. Stable, water-soluble, biocompatible poly(ethylene glycol)-block-poly(epsilon-caprolactone) NPs simultaneously co-encapsulating hydrophobic organic actives (beta-carotene) and inorganic imaging nanostructures (Au) are prepared using the flash nanoprecipitation process in a multi-inlet vortex mixer. These composite nanoparticles (CNPs) are produced with tunable sizes between 75 nm and 275 nm, narrow particle size distributions, high encapsulation efficiencies, specified component compositions, and long-term stability. The process is tunable and flexible because it relies on the control of mixing and aggregation timescales. It is anticipated that the technique can be applied to a variety of hydrophobic active compounds, fluorescent dyes, and inorganic nanostructures, yielding CNPs for combined therapy and multimodal imaging applications.

  12. Combinatorial synthesis of inorganic or composite materials

    DOEpatents

    Goldwasser, Isy; Ross, Debra A.; Schultz, Peter G.; Xiang, Xiao-Dong; Briceno, Gabriel; Sun, Xian-Dong; Wang, Kai-An

    2010-08-03

    Methods and apparatus for the preparation and use of a substrate having an array of diverse materials in predefined regions thereon. A substrate having an array of diverse materials thereon is generally prepared by delivering components of materials to predefined regions on a substrate, and simultaneously reacting the components to form at least two materials or, alternatively, allowing the components to interact to form at least two different materials. Materials which can be prepared using the methods and apparatus of the present invention include, for example, covalent network solids, ionic solids and molecular solids. More particularly, materials which can be prepared using the methods and apparatus of the present invention include, for example, inorganic materials, intermetallic materials, metal alloys, ceramic materials, organic materials, organometallic materials, nonbiological organic polymers, composite materials (e.g., inorganic composites, organic composites, or combinations thereof), etc. Once prepared, these materials can be screened for useful properties including, for example, electrical, thermal, mechanical, morphological, optical, magnetic, chemical, or other properties. Thus, the present invention provides methods for the parallel synthesis and analysis of novel materials having useful properties.

  13. Wear and fatigue behavior of nano-structured dental resin composites.

    PubMed

    Turssi, Cecilia P; Ferracane, Jack L; Ferracane, Lucas L

    2006-07-01

    Theoretically, nano-structured dental resin composites are purported to have increased wear and fatigue resistance compared with microfill composites and may favor the achievement of restoratives with better long-term performance. This study sought to assess the behavior of nano-structured composites resulting from either abrasion and fatigue loading. Ten specimens (12 x 5 x 2.5 mm) were prepared from each of five composites: Ceram-X mono, Filtek Supreme, Grandio, Premise, and Heliomolar (serving as the microfill control). A surface profile was recorded using a three-dimensional profiling system, and the specimens were subjected to 10(5) cycles of three-body abrasion in the new OHSU oral wear simulator. A second profile was generated and the before and after profiles were fit and analyzed. The volume loss and maximum depth of the wear facet on each specimen were calculated. Another 30 specimens (25 x 2 x 2 mm) were tested for flexural fatigue limit (FFL) in four-point bending via the staircase method. The test was carried out until 10(4) cycles were completed or until fracturing the specimen. One-way ANOVA and Tukey's test demonstrated greater volumetric loss for Grandio and Ceram-X than that observed for the remaining composites. Kruskal-Wallis and the least significant difference test ascertained that Heliomolar, Grandio, and Supreme showed significantly higher FFL than Ceram-X and Premise. In terms of wear and fatigue resistance, nano-structured composites may perform either similarly or comparatively worse than a microfilled composite.

  14. Charge transport across high surface area metal/diamond nanostructured composites.

    PubMed

    Plana, D; Humphrey, J J L; Bradley, K A; Celorrio, V; Fermín, D J

    2013-04-24

    High surface area composites featuring metal nanostructures and diamond particles have generated a lot of interest in the fields of heterogeneous catalysis, electrocatalysis, and sensors. Diamond surfaces provide a chemically robust framework for active nanostructures in comparison with sp(2) carbon supports. The present paper investigates the charge transport properties of high surface area films of high-pressure, high-temperature diamond particles in the presence and absence of metal nanostructures, employing electrochemical field-effect transistors. Oxygen- and hydrogen-terminated surfaces were generated on 500 nm diamond powders. Homogeneously distributed metal nanostructures, with metal volume fractions between ca. 5 and 20%, were either nucleated at the diamond particles by impregnation or incorporated from colloidal solution. Electrochemical field-effect transistor measurements, employing interdigitated electrodes, allowed the determination of composite conductivity as a function of electrode potential, as well as in air. In the absence of metal nanostructures, the lateral conductivity of the diamond assemblies in air is increased by over one order of magnitude upon hydrogenation of the particle surface. This observation is consistent with studies at diamond single crystals, although the somewhat modest change in conductivity suggests that charge transport is not only determined by the intrinsic surface conductivity of individual diamond particles but also by particle-to-particle charge transfer. Interestingly, the latter contribution effectively controls the assembly conductivity in the presence of an electrolyte solution as the difference between hydrogenated and oxygenated particles vanishes. The conductivity in the presence of metal nanoparticles is mainly determined by the metal volume fraction, while diamond surface termination and the presence of electrolyte solutions exert only minor effects. The experimental trends are discussed in terms of the

  15. Synthesis of morphology-tunable ZnO nanostructures via the composite hydroxide mediated approach for photocatalytic applications

    NASA Astrophysics Data System (ADS)

    Zhai, Bao-Gai; Ma, Qing-lan; Yang, Long; Huang, Yuan Ming

    2016-10-01

    Morphology-tunable ZnO nanostructures were prepared via the composite hydroxide mediated approach by simply tuning the temperature of the molten composite hydroxides. The synthesized ZnO nanostructures were characterized by means of scanning electron microscopy, transmission electron microscopy, x-ray diffraction, photoluminescence spectrophotometry, x-ray photoelectron spectroscopy and UV-vis spectroscopy. As the temperature of molten composite hydroxides increased from 170 °C to 240 °C, the morphology of ZnO nanostructures evolved from nanoparticles and nanorods, to nanoflowers and nanoplates, and finally to hierarchical nanospheres and nanosheets. Photocatalytic analysis revealed that the photocatalytic activity of the synthesized ZnO nanostructures was heavily dependent on their morphology. It was found that the ZnO nanostructures synthesized at 220 °C exhibited the highest photocatalytic activity with its first-order rate constant of 0.1334 min-1. As a contrast, the ZnO nanostructures synthesized at 170 °C exhibited the lowest photocatalytic activity with its first-order rate constant of 0.0511 min-1. We have demonstrated the composite hydroxide mediated approach as a technically sound, environmentally friendly methodology for creating a wide range of ZnO nanostructures.

  16. A review of nanostructured lithium ion battery materials via low temperature synthesis.

    PubMed

    Chen, Jiajun

    2013-01-01

    Nanostructured materials afford us new opportunities to improve the current technology for synthesizing Li ion batteries. Generating nanomaterials with new properties via an inexpensive approach offers a tremendous potential for realizing high performance Li-ion batteries. In this review, I mainly summarize some of the recent progress made, and describe the patents awarded on synthesizing nanostructured cathode materials for these batteries via low temperature wet- chemistry methods. From an economical view, such syntheses, especially hydrothermal synthesis, may offer the opportunities for significantly lowering the cost of manufacturing battery materials, while conferring distinct environmental advantages. Recent advances in in-situ (real time) X-ray diffraction for studying hydrothermal synthesis have great potential for bettering the rational design of advanced lithium-electrode materials. The development of this technique also will be discussed.

  17. Composite Materials for Maxillofacial Prostheses.

    DTIC Science & Technology

    1980-08-01

    projected composite systems are elastomeric-shelled, liquid-filled * microcapsules . Experiments continued on the interfacial polymerization process with...filled microcapsules . Experiments continued on the interfacial polymerization process, with spherical, sealed, capsules achieved. Needs identified are...consists of liquid-filled, elastomeric-shelled microcapsules held together to form a deformable mass; this is to simulate the semi-liquid cellular structure

  18. Ceramic composites: Enabling aerospace materials

    NASA Technical Reports Server (NTRS)

    Levine, S. R.

    1992-01-01

    Ceramics and ceramic matrix composites (CMC) have the potential for significant impact on the performance of aerospace propulsion and power systems. In this paper, the potential benefits are discussed in broad qualitative terms and are illustrated by some specific application case studies. The key issues in need of resolution for the potential of ceramics to be realized are discussed.

  19. Quantifying protein adsorption and function at nanostructured materials: enzymatic activity of glucose oxidase at GLAD structured electrodes.

    PubMed

    Jensen, Uffe B; Ferapontova, Elena E; Sutherland, Duncan S

    2012-07-31

    Nanostructured materials strongly modulate the behavior of adsorbed proteins; however, the characterization of such interactions is challenging. Here we present a novel method combining protein adsorption studies at nanostructured quartz crystal microbalance sensor surfaces (QCM-D) with optical (surface plasmon resonance SPR) and electrochemical methods (cyclic voltammetry CV) allowing quantification of both bound protein amount and activity. The redox enzyme glucose oxidase is studied as a model system to explore alterations in protein functional behavior caused by adsorption onto flat and nanostructured surfaces. This enzyme and such materials interactions are relevant for biosensor applications. Novel nanostructured gold electrode surfaces with controlled curvature were fabricated using colloidal lithography and glancing angle deposition (GLAD). The adsorption of enzyme to nanostructured interfaces was found to be significantly larger compared to flat interfaces even after normalization for the increased surface area, and no substantial desorption was observed within 24 h. A decreased enzymatic activity was observed over the same period of time, which indicates a slow conformational change of the adsorbed enzyme induced by the materials interface. Additionally, we make use of inherent localized surface plasmon resonances in these nanostructured materials to directly quantify the protein binding. We hereby demonstrate a QCM-D-based methodology to quantify protein binding at complex nanostructured materials. Our approach allows label free quantification of protein binding at nanostructured interfaces.

  20. Oxygen Compatibility Testing of Composite Materials

    NASA Technical Reports Server (NTRS)

    Engel, Carl D.; Watkins, Casey N.

    2006-01-01

    Composite materials offer significant weight-saving potential for aerospace applications in propellant and oxidizer tanks. This application for oxygen tanks presents the challenge of being oxygen compatible in addition to complying with the other required material characteristics. This effort reports on the testing procedures and data obtained in examining and selecting potential composite materials for oxygen tank usage. Impact testing of composites has shown that most of these materials initiate a combustion event when impacted at 72 ft-lbf in the presence of liquid oxygen, though testing has also shown substantial variability in reaction sensitivities to impact. Data for screening of 14 potential composites using the Bruceton method is given herein and shows that the 50-percent reaction frequencies range from 17 to 67 ft-lbf. The pressure and temperature rises for several composite materials were recorded to compare the energy releases as functions of the combustion reactions with their respective reaction probabilities. The test data presented are primarily for a test pressure of 300 psia in liquid oxygen. The impact screening process is compared with oxygen index and autogenous ignition test data for both the composite and the basic resin. The usefulness of these supplemental tests in helping select the most oxygen compatible materials is explored. The propensity for mechanical impact ignition of the composite compared with the resin alone is also examined. Since an ignition-free composite material at the peak impact energy of 72 ft-lbf has not been identified, composite reactivity must be characterized over the impact energy level and operating pressure ranges to provide data for hazard analyses in selecting the best potential material for liquid tank usage.

  1. A non-aqueous procedure to synthesize amino group bearing nanostructured organic-inorganic hybrid materials.

    PubMed

    Göring, M; Seifert, A; Schreiter, K; Müller, P; Spange, S

    2014-09-04

    Amino-functionalized organic-inorganic hybrid materials with a narrow distributed nanostructure of 2-4 nm in size were obtained by means of a template-free and non-aqueous procedure. Simultaneous twin polymerization of novel amino group containing twin monomers with 2,2'-spirobi[4H-1,3,2-benzodioxasiline] has been applied for this purpose. The amino groups of the organic-inorganic hybrid material are useful for post derivatization.

  2. Composite silicon nanostructure arrays fabricated on optical fibre by chemical etching of multicrystal silicon film

    NASA Astrophysics Data System (ADS)

    Zuo, Zewen; Zhu, Kai; Ning, Lixin; Cui, Guanglei; Qu, Jun; Huang, Wanxia; Shi, Yi; Liu, Hong

    2015-04-01

    Integrating nanostructures onto optical fibers presents a promising strategy for developing new-fashioned devices and extending the scope of nanodevices’ applications. Here we report the first fabrication of a composite silicon nanostructure on an optical fiber. Through direct chemical etching using an H2O2/HF solution, multicrystal silicon films with columnar microstructures are etched into a vertically aligned, inverted-cone-like nanorod array embedded in a nanocone array. A faster dissolution rate of the silicon at the void-rich boundary regions between the columns is found to be responsible for the separation of the columns, and thus the formation of the nanostructure array. The morphology of the nanorods primarily depends on the microstructure of the columns in the film. Through controlling the microstructure of the as-grown film and the etching parameters, the structural control of the nanostructure is promising. This fabrication method can be extended to a larger length scale, and it even allows roll-to-roll processing.

  3. Chemical composition of lunar material.

    PubMed

    Maxwell, J A; Abbey, S; Champ, W H

    1970-01-30

    Chemical and emission spectrographic analyses of three Apollo 11 samples, 10017-29, 10020-30, and 10084-132, are given. Major and minor constituents were determined both by conventional rock analysis methods and by a new composite scheme utilizing a lithium fluoborate method for dissolution of the samples and atomic absorption spectroscopy and colorimetry. Trace constituents were determined by optical emission spectroscopy involving a d-c arc, air-jet controlled.

  4. Advanced composite materials for precision segmented reflectors

    NASA Technical Reports Server (NTRS)

    Stein, Bland A.; Bowles, David E.

    1988-01-01

    The objective in the NASA Precision Segmented Reflector (PSR) project is to develop new composite material concepts for highly stable and durable reflectors with precision surfaces. The project focuses on alternate material concepts such as the development of new low coefficient of thermal expansion resins as matrices for graphite fiber reinforced composites, quartz fiber reinforced epoxies, and graphite reinforced glass. Low residual stress fabrication methods will be developed. When coupon specimens of these new material concepts have demonstrated the required surface accuracies and resistance to thermal distortion and microcracking, reflector panels will be fabricated and tested in simulated space environments. An important part of the program is the analytical modeling of environmental stability of these new composite materials concepts through constitutive equation development, modeling of microdamage in the composite matrix, and prediction of long term stability (including viscoelasticity). These analyses include both closed form and finite element solutions at the micro and macro levels.

  5. Method of producing catalytic materials for fabricating nanostructures

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-02-19

    Methods of fabricating nano-catalysts are described. In some embodiments the nano-catalyst is formed from a powder-based substrate material and is some embodiments the nano-catalyst is formed from a solid-based substrate material. In some embodiments the substrate material may include metal, ceramic, or silicon or another metalloid. The nano-catalysts typically have metal nanoparticles disposed adjacent the surface of the substrate material. The methods typically include functionalizing the surface of the substrate material with a chelating agent, such as a chemical having dissociated carboxyl functional groups (--COO), that provides an enhanced affinity for metal ions. The functionalized substrate surface may then be exposed to a chemical solution that contains metal ions. The metal ions are then bound to the substrate material and may then be reduced, such as by a stream of gas that includes hydrogen, to form metal nanoparticles adjacent the surface of the substrate.

  6. Composite Material Application to Liquid Rocket Engines

    NASA Technical Reports Server (NTRS)

    Judd, D. C.

    1982-01-01

    The substitution of reinforced plastic composite (RPC) materials for metal was studied. The major objectives were to: (1) determine the extent to which composite materials can be beneficially used in liquid rocket engines; (2) identify additional technology requirements; and (3) determine those areas which have the greatest potential for return. Weight savings, fabrication costs, performance, life, and maintainability factors were considered. Two baseline designs, representative of Earth to orbit and orbit to orbit engine systems, were selected. Weight savings are found to be possible for selected components with the substitution of materials for metal. Various technology needs are identified before RPC material can be used in rocket engine applications.

  7. Crustacean-derived biomimetic components and nanostructured composites.

    PubMed

    Grunenfelder, Lessa Kay; Herrera, Steven; Kisailus, David

    2014-08-27

    Over millions of years, the crustacean exoskeleton has evolved into a rigid, tough, and complex cuticle that is used for structural support, mobility, protection of vital organs, and defense against predation. The crustacean cuticle is characterized by a hierarchically arranged chitin fiber scaffold, mineralized predominately by calcium carbonate and/or calcium phosphate. The structural organization of the mineral and organic within the cuticle occurs over multiple length scales, resulting in a strong and tough biological composite. Here, the ultrastructural details observed in three species of crustacean are reviewed: the American lobster (Homarus americanus), the edible crab (Cancer pagurus), and the peacock mantis shrimp (Odontodactylus scyllarus). The Review concludes with a discussion of recent advances in the development of biomimetics with controlled organic scaffolding, mineralization, and the construction of nanoscale composites, inspired by the organization and formation of the crustacean cuticle.

  8. Nanostructured Tungsten Oxide Composite for High-Performance Gas Sensors

    PubMed Central

    Feng-Chen, Siyuan; Aldalbahi, Ali; Feng, Peter Xianping

    2015-01-01

    We report the results of composite tungsten oxide nanowires-based gas sensors. The morphologic surface, crystallographic structures, and chemical compositions of the obtained nanowires have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman scattering, respectively. The experimental measurements reveal that each wire consists of crystalline nanoparticles with an average diameter of less than 250 nm. By using the synthesized nanowires, highly sensitive prototypic gas sensors have been designed and fabricated. The dependence of the sensitivity of tungsten oxide nanowires to the methane and hydrogen gases as a function of time has been obtained. Various sensing parameters such as sensitivity, response time, stability, and repeatability were investigated in order to reveal the sensing ability. PMID:26512670

  9. Three-dimensional graphene/LiFePO{sub 4} nanostructures as cathode materials for flexible lithium-ion batteries

    SciTech Connect

    Ding, Y.H.; Ren, H.M.; Huang, Y.Y.; Chang, F.H.; Zhang, P.

    2013-10-15

    Graphical abstract: Graphene/LiFePO{sub 4} composites as a high-performance cathode material for flexible lithium-ion batteries have been prepared by using a co-precipitation method to synthesize graphene/LiFePO4 powders as precursors and then followed by a solvent evaporation process. - Highlights: • Flexible LiFePO{sub 4}/graphene films were prepared first time by a solvent evaporation process. • The flexible electrode exhibited a high discharge capacity without conductive additives. • Graphene network offers the electrode adequate strength to withstand repeated flexing. - Abstract: Three-dimensional graphene/LiFePO{sub 4} nanostructures for flexible lithium-ion batteries were successfully prepared by solvent evaporation method. Structural characteristics of flexible electrodes were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrochemical performance of graphene/LiFePO{sub 4} was examined by a variety of electrochemical testing techniques. The graphene/LiFePO{sub 4} nanostructures showed high electrochemical properties and significant flexibility. The composites with low graphene content exhibited a high capacity of 163.7 mAh g{sup −1} at 0.1 C and 114 mAh g{sup −1} at 5 C without further incorporation of conductive agents.

  10. Cumulative Damage Model for Advanced Composite Materials.

    DTIC Science & Technology

    1982-07-01

    ultimately used an exponential in the present example for added simplicity) and we norma - lize the function so that it becomes the modifier that determines...Testing and Design (Second Conference), ASTM STP 497, ASTM (1972) pp. 170-188. 5. Halpin, J. C., et al., "Characterization of Composites for the...Graphite Epoxy Composites," Proc. Symposium on Composite Materials: Testing and Design, ASTM , (Ma’rch 20, 1978) New Orleans, LA. 18. Hashin, Z. and Rotem

  11. Improved Materials for Composite and Adhesive Joints.

    DTIC Science & Technology

    1984-07-01

    Mechanical Testing 1 b. Composites Fabricated 2 2. RELATIONSHIP BETWEEN NEAT RESIN AND IN SITU COMPOSITE PROPERTIES 5 3. MATERIAL DEVELOPMENT 6 a...inspection revealed large variations in thickness across the width of the tape. This problem is serious in that the resin has a very high melt viscosity...and thus unfor- giving in correcting variations during composite processing. There is little or no resin loss during processing. The PEEK resin in

  12. Composite materials with improved phyllosilicate dispersion

    DOEpatents

    Chaiko, David J.

    2004-09-14

    The present invention provides phyllosilicates edge modified with anionic surfactants, composite materials made from the edge modified phyllosilicates, and methods for making the same. In various embodiments the phyllosilicates are also surface-modified with hydrophilic lipophilic balance (HLB) modifying agents, polymeric hydrotropes, and antioxidants. The invention also provides blends of edge modified phyllosilicates and semicrystalline waxes. The composite materials are made by dispersing the edge modified phyllosilicates with polymers, particularly polyolefins and elastomers.

  13. Fatigue and fracture research in composite materials

    NASA Technical Reports Server (NTRS)

    Obrien, T. K.

    1982-01-01

    The fatigue, fracture, and impact behavior of composite materials are investigated. Bolted and bonded joints are included. The solutions developed are generic in scope and are useful for a wide variety of structural applications. The analytical tools developed are used to demonstrate the damage tolerance, impact resistance, and useful fatigue life of structural composite components. Standard tests for screening improvements in materials and constituents are developed.

  14. Method to fabricate layered material compositions

    DOEpatents

    Fleming, James G.; Lin, Shawn-Yu

    2004-11-02

    A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

  15. Method to fabricate layered material compositions

    DOEpatents

    Fleming, James G.; Lin, Shawn-Yu

    2002-01-01

    A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

  16. Composite, ordered material having sharp surface features

    DOEpatents

    D'Urso, Brian R.; Simpson, John T.

    2006-12-19

    A composite material having sharp surface features includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite material having an etched surface wherein the protrusive phase protrudes from the surface to form a sharp surface feature. The sharp surface features can be coated to make the surface super-hydrophobic.

  17. Method of making a composite refractory material

    DOEpatents

    Morrow, M.S.; Holcombe, C.E.

    1995-09-26

    A composite refractory material is prepared by combining boron carbide with furan resin to form a mixture containing about 8 wt. % furan resin. The mixture is formed into a pellet which is placed into a grit pack comprising an oxide of an element such as yttrium to form a sinterable body. The sinterable body is sintered under vacuum with microwave energy at a temperature no greater than 2000 C to form a composite refractory material.

  18. Acoustic emission monitoring of polymer composite materials

    NASA Technical Reports Server (NTRS)

    Bardenheier, R.

    1981-01-01

    The techniques of acoustic emission monitoring of polymer composite materials is described. It is highly sensitive, quasi-nondestructive testing method that indicates the origin and behavior of flaws in such materials when submitted to different load exposures. With the use of sophisticated signal analysis methods it is possible the distinguish between different types of failure mechanisms, such as fiber fracture delamination or fiber pull-out. Imperfections can be detected while monitoring complex composite structures by acoustic emission measurements.

  19. Method of making a composite refractory material

    DOEpatents

    Morrow, Marvin S.; Holcombe, Cressie E.

    1995-01-01

    A composite refractory material is prepared by combining boron carbide with furan resin to form a mixture containing about 8 wt. % furan resin. The mixture is formed into a pellet which is placed into a grit pack comprising an oxide of an element such as yttrium to form a sinterable body. The sinterable body is sintered under vacuum with microwave energy at a temperature no greater than 2000.degree. C. to form a composite refractory material.

  20. Understanding the interfacial properties of nanostructured liquid crystalline materials for surface-specific delivery applications.

    PubMed

    Dong, Yao-Da; Larson, Ian; Barnes, Timothy J; Prestidge, Clive A; Allen, Stephanie; Chen, Xinyong; Roberts, Clive J; Boyd, Ben J

    2012-09-18

    Nonlamellar liquid crystalline dispersions such as cubosomes and hexosomes have great potential as novel surface-targeted active delivery systems. In this study, the influence of internal nanostructure, chemical composition, and the presence of Pluronic F127 as a stabilizer, on the surface and interfacial properties of different liquid crystalline particles and surfaces, was investigated. The interfacial properties of the bulk liquid crystalline systems with coexisting excess water were dependent on the internal liquid crystalline nanostructure. In particular, the surfaces of the inverse cubic systems were more hydrophilic than that of the inverse hexagonal phase. The interaction between F127 and the bulk liquid crystalline systems depended on the internal liquid crystalline structure and chemical composition. For example, F127 adsorbed to the surface of the bulk phytantriol cubic phase, while for monoolein cubic phase, F127 was integrated into the liquid crystalline structure. Last, the interfacial adsorption behavior of the dispersed liquid crystalline particles also depended on both the internal nanostructure and the chemical composition, despite the dispersions all being stabilized using F127. The findings highlight the need to understand the specific surface characteristics and the nature of the interaction with colloidal stabilizer for understanding and optimizing the behavior of nonlamellar liquid crystalline systems in surface delivery applications.

  1. Graphene-based Composite Materials

    NASA Astrophysics Data System (ADS)

    Rafiee, Mohammad Ali

    We investigated the mechanical properties, such as fracture toughness (KIc), fracture energy (GIc), ultimate tensile strength (UTS), Young¡¦s modulus (E), and fatigue crack propagation rate (FCPR) of epoxy-matrix composites with different weight fractions of carbon-based fillers, including graphene platelets (GPL), graphene nanoribbons (GNR), single-walled carbon nanotubes (SWNT), multi-walled carbon nanotubes (MWNT), and fullerenes (C60). Only ˜0.125 wt.% GPL was found to increase the KIc of the pure epoxy by ˜65% and the GIc by ˜115%. To get similar improvement, CNT and nanoparticle epoxy composites required one to two orders of magnitude greater weight fraction of nanofillers. Moreover, ˜0.125% wt.% GPL also decreased the fatigue crack propagation rate in the epoxy by ˜30-fold. The E value of 0.1 wt.% GPL/epoxy nanocomposite was ˜31% larger than the pure epoxy while there was only an increase of ˜3% for the SWNT composites. The UTS of the pristine epoxy was improved by ˜40% with GPLs in comparison with ˜14% enhancement for the MWNTs. The KIc of the GPL nanocomposite enhanced by ˜53% over the pristine epoxy compared to a ˜20% increase for the MWNT-reinforced composites. The results of the FCPR tests for the GPL nanocomposites showed a different trend. While the CNT nanocomposites were not effective enough to suppress the crack growth at high values of the stress intensity factor (DeltaK), the reverse behavior is observed for the GPL nanocomposites. The advantage of the GPLs over CNTs in terms of mechanical properties enhancement is due to their enormous specific surface area, enhanced adhesion at filler/epoxy interface (because of the wrinkled surfaces of GPLs), as well as the planar structure of the GPLs. We also show that unzipping of MWNTs into graphene nanoribbons (GNRs) enhances the load transfer effectiveness in epoxy nanocomposites. For instance, at ˜0.3 wt.% of fillers, the Young's modulus (E) of the epoxy nanocomposite with GNRs increased

  2. Nanostructured thin film-based near-infrared tunable perfect absorber using phase-change material

    NASA Astrophysics Data System (ADS)

    Kocer, Hasan

    2015-01-01

    Nanostructured thin film absorbers embedded with phase-change thermochromic material can provide a large level of absorption tunability in the near-infrared region. Vanadium dioxide was employed as the phase-change material in the designed structures. The optical absorption properties of the designed structures with respect to the geometric and material parameters were systematically investigated using finite-difference time-domain computations. Absorption level of the resonance wavelength in the near-IR region was tuned from the perfect absorption level to a low level (17%) with a high positive dynamic range of near-infrared absorption intensity tunability (83%). Due to the phase transition of vanadium dioxide, the resonance at the near-infrared region is being turned on and turned off actively and reversibly under the thermal bias, thereby rendering these nanostructures suitable for infrared camouflage, emitters, and sensors.

  3. Atomic layer deposition of nanostructured materials for energy and environmental applications.

    PubMed

    Marichy, Catherine; Bechelany, Mikhael; Pinna, Nicola

    2012-02-21

    Atomic layer deposition (ALD) is a thin film technology that in the past two decades rapidly developed from a niche technology to an established method. It proved to be a key technology for the surface modification and the fabrication of complex nanostructured materials. In this Progress Report, after a short introduction to ALD and its chemistry, the versatility of the technique for the fabrication of novel functional materials will be discussed. Selected examples, focused on its use for the engineering of nanostructures targeting applications in energy conversion and storage, and on environmental issues, will be discussed. Finally, the challenges that ALD is now facing in terms of materials fabrication and processing will be also tackled.

  4. Effective Behavior of Composite Materials.

    DTIC Science & Technology

    2014-09-26

    7AD-A158 941 EFFECTIVE BEHAVIOR OF COMPOSITE MTERIRLS(A) NEW YORK i/i UNIV MY COURANT INST OF ATHEMATICAL SCIENCES 6CPAPANICOLAOU 23 APR 85 5274192... Courant ilfapphcabt e Instit.te of Math. Sciences AF0SR/NM 6c. ADDRESS Cit). State and ZIP Code, 7b. ADDRESS (City. State and ZIP Code) 251 Mercer St Bldg...Papanicolaou Courant Institute 251 Mercer Street New York, N.Y. 10012 i~istr~utlo2 During this period two thesis ipja b&have completed ’their work and have

  5. RNA as a stable polymer to build controllable and defined nanostructures for material and biomedical applications

    PubMed Central

    Li, Hui; Lee, Taek; Dziubla, Thomas; Pi, Fengmei; Guo, Sijin; Xu, Jing; Li, Chan; Haque, Farzin; Liang, Xing-Jie; Guo, Peixuan

    2015-01-01

    Summary The value of polymers is manifested in their vital use as building blocks in material and life sciences. Ribonucleic acid (RNA) is a polynucleic acid, but its polymeric nature in materials and technological applications is often overlooked due to an impression that RNA is seemingly unstable. Recent findings that certain modifications can make RNA resistant to RNase degradation while retaining its authentic folding property and biological function, and the discovery of ultra-thermostable RNA motifs have adequately addressed the concerns of RNA unstability. RNA can serve as a unique polymeric material to build varieties of nanostructures including nanoparticles, polygons, arrays, bundles, membrane, and microsponges that have potential applications in biomedical and material sciences. Since 2005, more than a thousand publications on RNA nanostructures have been published in diverse fields, indicating a remarkable increase of interest in the emerging field of RNA nanotechnology. In this review, we aim to: delineate the physical and chemical properties of polymers that can be applied to RNA; introduce the unique properties of RNA as a polymer; review the current methods for the construction of RNA nanostructures; describe its applications in material, biomedical and computer sciences; and, discuss the challenges and future prospects in this field. PMID:26770259

  6. Preparation and characterization of nanostructured NiO/MnO{sub 2} composite electrode for electrochemical supercapacitors

    SciTech Connect

    Liu Enhui Li Wen; Li Jian; Meng Xiangyun; Ding Rui; Tan Songting

    2009-05-06

    Nanostructured nickel-manganese oxides composite was prepared by the sol-gel and the chemistry deposition combination new route. The surface morphology and structure of the composite were characterized by scanning electron microscope and X-ray diffraction. The as-synthesized NiO/MnO{sub 2} samples exhibit higher surface area of 130-190 m{sup 2} g{sup -1}. Cyclic voltammetry and galvanostatic charge/discharge measurements were applied to investigate the electrochemical performance of the composite electrodes with different ratios of NiO/MnO{sub 2}. When the mass ratio of MnO{sub 2} and NiO in composite material is 80:20, the specific capacitance value of NiO/MnO{sub 2} calculated from the cyclic voltammetry curves is 453 F g{sup -1}, for pure NiO and MnO{sub 2} are 209, 330 F g{sup -1} in 6 mol L{sup -1} KOH electrolyte and at scan rate of 10 mV s{sup -1}, respectively. The specific capacitance of NiO/MnO{sub 2} electrode is much larger than that of each pristine component. Moreover, the composite electrodes showed high power density and stable electrochemical properties.

  7. Enhancement of Radiation Tolerance by Interfaces in Nanostructured Metallic Materials

    DTIC Science & Technology

    2013-06-05

    Bacon , Philosophical Magazine, 86 (2006) 2295-2313. [10] N.M. Ghoniem, B.N. Singh, L.Z. Sun, T. Dı́az de la Rubia, Journal of Nuclear Materials, 276...327 (2010) 1587-1588. [33] Y.N. Osetsky, D.J. Bacon , A. Serra, B.N. Singh, S.I. Golubov, Journal of Nuclear Materials, 276 (2000) 65-77. [34] D.J... Bacon , Y.N. Osetsky, R. Stoller, R.E. Voskoboinikov, Journal of Nuclear Materials, 323 (2003) 152-162. [35] Y. Matsukawa, S.J. Zinkle, Science, 318

  8. [The application of the nanostructured bioplastic material for the plastic reconstruction of perforations in the nasal septum].

    PubMed

    Grigor'eva, M V; Akimov, A V; Bagautdinov, A A

    2014-01-01

    The objective of the present work was to estimate the effectiveness of the application of the nanostructured bioplastic material for the plastic reconstruction of perforations in the nasal septum. A total of 80 patients were recruited for the study. Half of them underwent plastic reconstruction of perforations in the nasal septum with the application of the nanostructured bioplastic material. Forty patients were treated using no biotransplants. The functional state of nasal cavity mucosa was evaluated before and after surgery. It is concluded that the nanostructured bioplastic material used in the present study ensures efficacious reconstruction of nasal septum integrity after plastic correction of septal perforations.

  9. Composite multifunctional nanostructures based on ZnO tetrapods and superparamagnetic Fe3O4 nanoparticles.

    PubMed

    Villani, M; Rimoldi, T; Calestani, D; Lazzarini, L; Chiesi, V; Casoli, F; Albertini, F; Zappettini, A

    2013-04-05

    A nanocomposite material is obtained by coupling superparamagnetic magnetite nanoparticles (Fe3O4 NP) and vapor phase grown zinc oxide nanostructures with 'tetrapod' morphology (ZnO TP). The aim is the creation of a multifunctional material which retains the attractive features of ZnO (e.g. surface reactivity, strong UV emission, piezoelectricity) together with added magnetism. Structural, morphological, optical, magnetic and functional characterization are performed. In particular, the high saturation magnetization of Fe3O4 NP (above 50 A m(2) kg(-1)), the strong UV luminescence and the enhanced photocatalytic activity of coupled nanostructures are discussed. Thus the nanocomposite turns out to be suitable for applications in energy harvesting and conversion, gas- and bio-sensing, bio-medicine and filter-free photocatalysis.

  10. CRYOGENIC ADSORPTION OF HYDROGEN ISOTOPES OVER NANO-STRUCTURED MATERIALS

    SciTech Connect

    Xiao, S.; Heung, L.

    2010-10-07

    Porous materials such as zeolites, activated carbon, silica gels, alumina and a number of industrial catalysts are compared and ranked for hydrogen and deuterium adsorption at liquid nitrogen temperature. All samples show higher D{sub 2} adsorption than that of H{sub 2}, in which a HY sample has the greatest isotopic effect while 13X has the highest hydrogen uptake capacity. Material's moisture content has significant impact to its hydrogen uptake. A material without adequate drying could result in complete loss of its adsorption capacity. Even though some materials present higher H{sub 2} adsorption capacity at full pressure, their adsorption at low vapor pressure may not be as good as others. Adsorption capacity in a dynamic system is much less than in a static system. A sharp desorption is also expected in case of temperature upset.

  11. Intrinsically Survivable Structural Composite Materials

    DTIC Science & Technology

    2001-02-01

    Coefficient 14 2.2.2 Low-Temperature Precure Treatment (LTPT) 16 2.2.3 Investigation of Several Commercially Available Organoclays 18 2.2.4 High-Shear...of material. Additional commercially available organoclay samples all flocculated to a greater extent than the original S30A. Other attempts to...nanocomposites. A series of epoxy-organosilicate nanocomposites have been successfully prepared with the nanosheets of the nano- organoclay uniformly and

  12. Center for Cement Composite Materials

    DTIC Science & Technology

    1990-01-31

    pastes have shown that the matrix is microporous; mesopores are absent unless the material is allowed to dry out. This results in water adsorption at low...only to water. When subsequently dried a portion of3 the porosity is converted to larger mesopores . • Only about one third of the cement reacts in a...Frictional sliding, in this case was characterized by a decreasing slope in the loading curve followed by hysteresis in the unload/reloading curves

  13. Realization of New and Enhanced Materials Properties Through Nanostructural Control

    DTIC Science & Technology

    2007-06-11

    methods have been used to guide the design of novel new organic electroactive materials (e.g., electro - optic binary chromophore organic glasses...These new materials have yielded electro - optic coefficients as high as 450 pm/V (15 times lithium niobate) with auxiliary properties of modest optical... electro - optic activity has been achieved for the first time and theoretical conclusions have been verified by a number of new measurement techniques

  14. Fundamental Understanding and Theoretical Design of Novel Nanostructured Semiconductor Materials

    DTIC Science & Technology

    2012-01-04

    approach, and transport properties including electrical conductivity and Seebeck coefficients using our newly developed transport codes. Specific...photovoltaic materials and transparent conducting oxides. Electronic structure and volume effect on thermoelectric transport in p-type Bi and Sb...technologies. The efficiency of TE materials is represented by the figure of merit, ZT=SlaT/ (Ke+K/.), where S is the Seebeck coefficient, a is the electrical

  15. NANOSTRUCTURED CERAMICS AND COMPOSITES FOR REFRACTORY APPLICATIONS IN COAL GASIFICATION

    SciTech Connect

    Paul Brown

    2005-01-31

    A class of ceramics, capable of exhibiting low coefficients of thermal expansion and catalytic properties was investigated. Investigations were directed towards nanoengineering of NZP ceramics and NZP-based composites by chemical means by controlling their compositions and processing variables. NaZr{sub 2}(PO{sub 4}){sub 3} (NZP) was synthesized by combining water-soluble precursors leading to the precipitation of a gel that was dried, calcined, pressed into pellets, then fired at 850 C. Without chemical additives, the resulting ceramic comprised pores ranging in size from approximately 25 to 50 nm and a surface area of about 30m{sup 2}/g. Hydroxyapatite, which has a needle-like morphology, was mechanically mixed with the calcined gel to template NZP crystallization. What resulted was a coarsening of the pore structure and a decrease in surface area. When copper nitrate was added to the solution during synthesis, the resulting ceramic underwent shrinkage upon firing as well as an increase in strength. HAp and copper additions combined resulted in 40% volume shrinkage and a doubling of the tensile strength to 16MPa. A very different type of porosity was achieved when silica was partly substituted for phosphorous in the NZP structure. Na{sub 3}Zr{sub 2}(Si{sub 2}P)O{sub 12} (NASCION) was synthesized in the same manner as NZP, but the fired ceramic possessed a reticulated pore structure comprising large cavities ranging in size from 5 to 50 {micro}m. The NASCION ceramic either shrank or expanded upon firing depending on when the silica was added during synthesis. When the silica precursor (amorphous, precipitated silica) was added before the calcining step, the pressed pellets expanded during firing, whereas they shrank when the silica was added after the gel was calcined. The observed dilation increased with increasing calcining temperature and particle size, up to 26%. The contraction of the ceramic when fired increased with increasing calcining temperature and a

  16. 3-D textile reinforcements in composite materials

    SciTech Connect

    Miravete, A.

    1999-11-01

    Laminated composite materials have been used in structural applications since the 1960s. However, their high cost and inability to accommodate fibers in the laminate`s thickness direction greatly reduce their damage tolerance and impact resistance. The second generation of materials--3-D textile reinforced composites--offers significant cost reduction, and by incorporating reinforcement in the thickness direction, dramatically increases damage tolerance and impact resistance. However, methods for predicting mechanical properties of 3-D textile reinforced composite materials tend to be more complex. These materials also have disadvantages--particularly in regard to crimps in the yarns--that require more research. Textile preforms, micro- and macromechanical modeling, manufacturing processes, and characterization all need further development. As researchers overcome these problems, this new generation of composites will emerge as a highly competitive family of materials. This book provides a state-of-the-art account of this promising technology. In it, top experts describe the manufacturing processes, highlight the advantages, identify the main applications, analyze methods for predicting mechanical properties, and detail various reinforcement strategies, including grid structure, knitted fabric composites, and the braiding technique. Armed with the information in this book, readers will be prepared to better exploit the advantages of 3-D textile reinforced composites, overcome its disadvantages, and contribute to the further development of the technology.

  17. Oxygen Compatibility Testing of Composite Materials

    NASA Technical Reports Server (NTRS)

    Graf, Neil A.; Hudgins, Richard J.; McBain, Michael

    2000-01-01

    The development of polymer composite liquid oxygen LO2 tanks is a critical step in creating the next generation of launch vehicles. Future launch vehicles need to minimize the gross liftoff weight (GLOW), which is possible due to the 25%-40% reduction in weight that composite materials could provide over current aluminum technology. Although a composite LO2 tank makes these weight savings feasible, composite materials have not historically been viewed as "LO2 compatible." To be considered LO2 compatible, materials must be selected that will resist any type of detrimental, combustible reaction when exposed to usage environments. This is traditionally evaluated using a standard set of tests. However, materials that do not pass the standard tests can be shown to be safe for a particular application. This paper documents the approach and results of a joint NASA/Lockheed Martin program to select and verify LO2 compatible composite materials for liquid oxygen fuel tanks. The test approach developed included tests such as mechanical impact, particle impact, puncture, electrostatic discharge, friction, and pyrotechnic shock. These tests showed that composite liquid oxygen tanks are indeed feasible for future launch vehicles.

  18. Automotive applications for advanced composite materials

    NASA Technical Reports Server (NTRS)

    Deutsch, G. C.

    1978-01-01

    A description is presented of nonaerospace applications for advanced composite materials with special emphasis on the automotive applications. The automotive industry has to satisfy exacting requirements to reduce the average fuel consumption of cars. A feasible approach to accomplish this involves the development of composites cars with a total weight of 2400 pounds and a fuel consumption of 33 miles per gallon. In connection with this possibility, the automotive companies have started to look seriously at composite materials. The aerospace industry has over the past decade accumulated a considerable data base on composite materials and this is being made available to the nonaerospace sector. However, the automotive companies will place prime emphasis on low cost resins which lend themselves to rapid fabrication techniques.

  19. Ultrasonic stress wave characterization of composite materials

    NASA Technical Reports Server (NTRS)

    Duke, J. C., Jr.; Henneke, E. G., II; Stinchcomb, W. W.

    1986-01-01

    The work reported covers three simultaneous projects. The first project was concerned with: (1) establishing the sensitivity of the acousto-ultrasonic method for evaluating subtle forms of damage development in cyclically loaded composite materials, (2) establishing the ability of the acousto-ultrasonic method for detecting initial material imperfections that lead to localized damage growth and final specimen failure, and (3) characteristics of the NBS/Proctor sensor/receiver for acousto-ultrasonic evaluation of laminated composite materials. The second project was concerned with examining the nature of the wave propagation that occurs during acoustic-ultrasonic evaluation of composite laminates and demonstrating the role of Lamb or plate wave modes and their utilization for characterizing composite laminates. The third project was concerned with the replacement of contact-type receiving piezotransducers with noncontacting laser-optical sensors for acousto-ultrasonic signal acquisition.

  20. Dental applications of nanostructured bioactive glass and its composites

    PubMed Central

    Polini, Alessandro; Bai, Hao; Tomsia, Antoni P.

    2013-01-01

    To improve treatments for bone or dental trauma, and for diseases such as osteoporosis, cancer, and infections, scientists who perform basic research are collaborating with clinicians to design and test new biomaterials for the regeneration of lost or injured tissue. Developed some 40 years ago, bioactive glass (BG) has recently become one of the most promising biomaterials, a consequence of discoveries that its unusual properties elicit specific biological responses inside the body. Among these important properties are the capability of BG to form strong interfaces with both hard and soft tissues, and its release of ions upon dissolution. Recent developments in nanotechnology have introduced opportunities for materials sciences to advance dental and bone therapies. For example, the applications for BG expand as it becomes possible to finely control structures and physicochemical properties of materials at the molecular level. Here we review how the properties of these materials have been enhanced by the advent of nanotechnology; and how these developments are producing promising results in hard-tissue regeneration and development of innovative BG-based drug-delivery systems. PMID:23606653

  1. Dental applications of nanostructured bioactive glass and its composites.

    PubMed

    Polini, Alessandro; Bai, Hao; Tomsia, Antoni P

    2013-01-01

    To improve treatments of bone or dental trauma and diseases such as osteoporosis, cancer, and infections, scientists who perform basic research are collaborating with clinicians to design and test new biomaterials for the regeneration of lost or injured tissue. Developed some 40 years ago, bioactive glass (BG) has recently become one of the most promising biomaterials, a consequence of discoveries that its unusual properties elicit specific biological responses inside the body. Among these important properties are the capability of BG to form strong interfaces with both hard and soft tissues, and its release of ions upon dissolution. Recent developments in nanotechnology have introduced opportunities for materials sciences to advance dental and bone therapies. For example, the applications for BG expand as it becomes possible to finely control structures and physicochemical properties of materials at the molecular level. Here, we review how the properties of these materials have been enhanced by the advent of nanotechnology, and how these developments are producing promising results in hard-tissue regeneration and development of innovative BG-based drug delivery systems.

  2. Thermographic stress analysis of composite materials

    SciTech Connect

    Zhang, D.; Sandor, B.I.; Enke, N.F. Department of Defence, Aeronautical Research Laboratories, Melbourne )

    1990-03-01

    Several critical aspects of stress measurements in composite materials by thermographic stress analysis (TSA; also SPATE method) have been investigated. The emphasis is on the observed effects of thermal-expansion coefficients with positive and negative signs, thickness of surface coating, and absolute temperature increases in the material due to cyclic loading. Heat transfer and mean stress effects are also discussed. 23 refs.

  3. Synthesis and characterization of inorganic nanostructured materials for advanced energy storage

    NASA Astrophysics Data System (ADS)

    Xie, Jin

    The performance of advanced energy storage devices is intimately connected to the designs of electrodes. To enable significant developments in this research field, we need detailed information and knowledge about how the functions and performances of the electrodes depend on their chemical compositions, dimensions, morphologies, and surface properties. This thesis presents my successes in synthesizing and characterizing electrode materials for advanced electrochemical energy storage devices, with much attention given to understanding the operation and fading mechanism of battery electrodes, as well as methods to improve their performances and stabilities. This dissertation is presented within the framework of two energy storage technologies: lithium ion batteries and lithium oxygen batteries. The energy density of lithium ion batteries is determined by the density of electrode materials and their lithium storage capabilities. To improve the overall energy densities of lithium ion batteries, silicon has been proposed to replace lithium intercalation compounds in the battery anodes. However, with a ~400% volume expansion upon fully lithiation, silicon-based anodes face serious capacity degradation in battery operation. To overcome this challenge, heteronanostructure-based Si/TiSi2 were designed and synthesized as anode materials for lithium ion batteries with long cycling life. The performance and morphology relationship was also carefully studied through comparing one-dimensional and two-dimensional heteronanostructure-based silicon anodes. Lithium oxygen batteries, on the other hand, are devices based on lithium conversion chemistries and they offer higher energy densities compared to lithium ion batteries. However, existing carbon based electrodes in lithium oxygen batteries only allow for battery operation with limited capacity, poor stability and low round-trip efficiency. The degradation of electrolytes and carbon electrodes have been found to both contribute

  4. Synthesis and microwave absorption properties of graphene/nickel composite materials

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoxia; Yu, Mingxun; Zhang, Wei; Zhang, Baoqin; Dong, Lifeng

    2015-03-01

    Graphene/nickel composite materials were successfully prepared via a one-step in situ reduction from nickel chloride, graphene oxide, and hydrazine at 80 °C for 3 h. Face-centered cubic Ni nanostructures with uniform size and high dispersion assembled on graphene sheets. Through the measurement of complex relative permittivity and permeability, their microwave absorption properties were evaluated. In comparison with pure Ni nanoparticles and graphene, the composite materials demonstrated much better characteristics of microwave absorption. The lowest reflection loss value of the composites with a thickness of 3 mm can reach -23.3 dB at 7.5 GHz. Our research reveals that graphene/Ni composites are promising microwave absorption materials with desirable absorption properties and reduced material weight.

  5. Photoswitching and Thermoresponsive Properties of Conjugated Multi-chromophore Nanostructured Materials.

    PubMed

    Bhattacharyya, Santanu; Jana, Bikash; Sain, Sumanta; Barman, Monoj Kumar; Pradhan, Swapan Kumar; Patra, Amitava

    2015-12-16

    Conjugated multi-chromophore organic nanostructured materials have recently emerged as a new class of functional materials for developing efficient light-harvesting, photosensitization, photocatalysis, and sensor devices because of their unique photophysical and photochemical properties. Here, we demonstrate the formation of various nanostructures (fibers and flakes) related to the molecular arrangement (H-aggregation) of quaterthiophene (QTH) molecules and their influence on the photophysical properties. XRD studies confirm that the fiber structure consists of >95% crystalline material, whereas the flake structure is almost completely amorphous and the microstrain in flake-shaped QTH is significantly higher than that of QTH in solution. The influence of the aggregation of the QTH molecules on their photoswitching and thermoresponsive photoluminescence properties is revealed. Time-resolved anisotropic studies further unveil the relaxation dynamics and restricted chromophore properties of the self-assembled nano/microstructured morphologies. Further investigations should pave the way for the future development of organic electronics, photovoltaics, and light-harvesting systems based on π-conjugated multi-chromophore organic nanostructured materials.

  6. Magnetic porous composite material: Synthesis and properties

    NASA Astrophysics Data System (ADS)

    Peretyat'ko, P. I.; Kulikov, L. A.; Melikhov, I. V.; Perfil'ev, Yu. D.; Pal', A. F.; Timofeev, M. A.; Gudoshnikov, S. A.; Usov, N. A.

    2015-10-01

    A new method of obtaining magnetic porous composite materials is described, which is based on the self-propagating high-temperature synthesis (SHS) in the form of solid-phase combustion. The SHS process involves transformation of the nonmagnetic α-Fe2O3 particles (contained in the initial mixture) into magnetic Fe3O4 particles. The synthesized material comprises a porous carbonaceous matrix with immobilized Fe3O4 particles. The obtained composite has been characterized by electron microscopy, X-ray diffraction, Mössbauer spectroscopy, and magnetic measurements. The sorption capacity of the porous material has been studied.

  7. Synthesis and characterization of large specific surface area nanostructured amorphous silica materials.

    PubMed

    Marquez-Linares, Francisco; Roque-Malherbe, Rolando M A

    2006-04-01

    Large specific surface area materials attract wide attention because of their applications in adsorption, catalysis, and nanotechnology. In the present study, we describe the synthesis and characterization of nanostructured amorphous silica materials. These materials were obtained by means of a modification of the Stobe-Fink-Bohn (SFB) method. The morphology and essential features of the synthesized materials have been studied using an automated surface area and pore size analyzer and scanning electron microscopy. The existence of a micro/mesoporous structure in the obtained materials has been established. It was also found that the obtained particle packing materials show large specific surface area up to 1,600 m2/g. (To our best knowledge, there is no any reported amorphous silica material with such a higher specific surface area.) The obtained materials could be useful in the manufacture of adsorbents, catalyst supports, and other nanotechnological applications.

  8. Materials analysis by ultrasonics: Metals, ceramics, composites

    NASA Technical Reports Server (NTRS)

    Vary, Alex (Editor)

    1987-01-01

    Research results in analytical ultrasonics for characterizing structural materials from metals and ceramics to composites are presented. General topics covered by the conference included: status and advances in analytical ultrasonics for characterizing material microstructures and mechanical properties; status and prospects for ultrasonic measurements of microdamage, degradation, and underlying morphological factors; status and problems in precision measurements of frequency-dependent velocity and attenuation for materials analysis; procedures and requirements for automated, digital signal acquisition, processing, analysis, and interpretation; incentives for analytical ultrasonics in materials research and materials processing, testing, and inspection; and examples of progress in ultrasonics for interrelating microstructure, mechanical properties, and dynamic response.

  9. Temperature Prediction in a Free-Burning Arc and Electrodes for Nanostructured Materials and Systems.

    PubMed

    Lee, Won-Ho; Kim, Youn-Jea; Lee, Jong-Chul

    2015-11-01

    Temperature in a free-burning arc used for synthesis of nanoparticles and nanostructured materials is generally around 20,000 K just below the cathode, falling to about 15,000 K just above the anode, and decreasing rapidly in the radial direction. Therefore, the electrode erosion is indispensable for these atmospheric plasma systems, as well as for switching devices, due to the high heat flux transferred from high temperature arcs to electrodes, but experimental and theoretical works have not identified the characteristic phenomena because of the complex physical processes. To the previous study, we have focused on the arc self-induced fluid flow in a free-burning arc using the computational fluid dynamics (CFD) technique. At this time, our investigation is concerned with the whole region of free-burning high-intensity arcs including the tungsten cathode, the arc plasma and the anode using a unified numerical model for applying synthesis of nanoparticles and nanostructured materials practically.

  10. Antireflection effects at nanostructured material interfaces and the suppression of thin-film interference.

    PubMed

    Yang, Qiaoyin; Zhang, Xu A; Bagal, Abhijeet; Guo, Wei; Chang, Chih-Hao

    2013-06-14

    Thin-film interference is a well-known effect, and it is commonly observed in the colored appearance of many natural phenomena. Caused by the interference of light reflected from the interfaces of thin material layers, such interference effects can lead to wavelength and angle-selective behavior in thin-film devices. In this work, we describe the use of interfacial nanostructures to eliminate interference effects in thin films. Using the same principle inspired by moth-eye structures, this approach creates an effective medium where the index is gradually varying between the neighboring materials. We present the fabrication process for such nanostructures at a polymer-silicon interface, and experimentally demonstrate its effectiveness in suppressing thin-film interference. The principle demonstrated in this work can lead to enhanced efficiency and reduce wavelength/angle sensitivity in multilayer optoelectronic devices.

  11. Nanostructured Interfaces for Organized Mesoscopic Biotic-Abiotic Materials

    DTIC Science & Technology

    2011-09-30

    material for lithium batteries and solar cells . Previously, the proteins silicatein, lysozyme, silaffins, and amino- acids have been employed for...a fundamental basis for prospective ultra-sensing platform from hybrid organized nanomaterials for chemical, optical, and biological applications...with potential for dramatic miniaturization and superior sensitivity of lightweight hybrid sensor arrays. Students trained in this field will form a

  12. Producing Three Dimensional Nanostructured Magnetic Materials for Novel Magnetic Devices

    DTIC Science & Technology

    2012-02-22

    Hc) and remanance magnetization (Mr). A review of our processing technique was published in Annual Review of Materials Research [2]. (c...crystallographic magnetic directions can have higher coercivities, remanences , and/or exchange coupling. We produced preferentially ordered magnetic iron

  13. Realization of New and Enhanced Materials Properties Through Nanostructural Control

    DTIC Science & Technology

    2006-05-15

    Fifield, L. R. Dalton, A. Mazzoldi, D. De-Rossi, I. I. Khayrullin , and R. H. Baughman, "Pneumatic Carbon Nanotube Actuators," Adv. Mater., 14, 1728-32 (2002... Khayrullin , and B. H. Baughman, "Pneumatic Actuator Response from Carbon Nanotube Sheets," Materials Research Society Symposium Proceedings, v. 706

  14. Using biological inspiration to engineer functional nanostructured materials.

    PubMed

    Wendell, David W; Patti, Jordan; Montemagno, Carlo D

    2006-11-01

    Humans have always looked to nature for design inspiration, and material design on the molecular level is no different. Here we explore how this idea applies to nanoscale biomimicry, specifically examining both recent advances and our own work on engineering lipid and polymer membrane systems with cellular processes.

  15. Functional Scanning Probe Imaging of Nanostructured Solar Energy Materials.

    PubMed

    Giridharagopal, Rajiv; Cox, Phillip A; Ginger, David S

    2016-09-20

    From hybrid perovskites to semiconducting polymer/fullerene blends for organic photovoltaics, many new materials being explored for energy harvesting and storage exhibit performance characteristics that depend sensitively on their nanoscale morphology. At the same time, rapid advances in the capability and accessibility of scanning probe microscopy methods over the past decade have made it possible to study processing/structure/function relationships ranging from photocurrent collection to photocarrier lifetimes with resolutions on the scale of tens of nanometers or better. Importantly, such scanning probe methods offer the potential to combine measurements of local structure with local function, and they can be implemented to study materials in situ or devices in operando to better understand how materials evolve in time in response to an external stimulus or environmental perturbation. This Account highlights recent advances in the development and application of scanning probe microscopy methods that can help address such questions while filling key gaps between the capabilities of conventional electron microscopy and newer super-resolution optical methods. Focusing on semiconductor materials for solar energy applications, we highlight a range of electrical and optoelectronic scanning probe microscopy methods that exploit the local dynamics of an atomic force microscope tip to probe key properties of the solar cell material or device structure. We discuss how it is possible to extract relevant device properties using noncontact scanning probe methods as well as how these properties guide materials development. Specifically, we discuss intensity-modulated scanning Kelvin probe microscopy (IM-SKPM), time-resolved electrostatic force microscopy (trEFM), frequency-modulated electrostatic force microscopy (FM-EFM), and cantilever ringdown imaging. We explain these developments in the context of classic atomic force microscopy (AFM) methods that exploit the physics of

  16. Copper and Zinc Oxide Composite Nanostructures for Solar Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Wu, Fei

    Solar energy is a clean and sustainable energy source to counter global environmental issues of rising atmospheric CO2 levels and depletion of natural resources. To extract useful work from solar energy, silicon-based photovoltaic devices are extensively used. The technological maturity and the high quality of silicon (Si) make it a material of choice. However limitations in Si exist, ranging from its indirect band gap to low light absorption coefficient and energy and capital intensive crystal growth schemes. Therefore, alternate materials that are earth-abundant, benign and simpler to process are needed for developing new platforms for solar energy harvesting applications. In this study, we explore oxides of copper (CuO and Cu2O) in a nanowire morphology as alternate energy harvesting materials. CuO has a bandgap of 1.2 eV whereas Cu2O has a bandgap of 2.1 eV making them ideally suited for absorbing solar radiation. First, we develop a method to synthesize vertical, single crystalline CuO and Cu2O nanowires of ~50 microm length and aspect ratios of ~200. CuO nanowire arrays are synthesized by thermal oxidation of Cu foils. Cu2O nanowire arrays are synthesized by thermal reduction of CuO nanowires. Next, surface engineering of these nanowires is achieved using atomic layer deposition (ALD) of ZnO. By depositing 1.4 nm of ZnO, a highly defective surface is produced on the CuO nanowires. These defects are capable of trapping charge as is evident through persistent photoconductivity measurements of ZnO coated CuO nanowires. The same nanowires serve as efficient photocatalysts reducing CO2 to CO with a yield of 1.98 mmol/g-cat/hr. Finally, to develop a robust platform for flexible solar cells, a protocol to transfer vertical CuO nanowires inside flexible polydimethylsiloxane (PDMS) is demonstrated. Embedded CuO nanowires-ZnO pn junctions show a VOC of 0.4 V and a JSC of 10.4 microA/cm2 under white light illumination of 5.7 mW/cm2. Thus, this research provides broad

  17. Comparison of the structural and chemical composition of two unique micro/nanostructures produced by femtosecond laser interactions on nickel

    SciTech Connect

    Zuhlke, Craig A.; Anderson, Troy P.; Alexander, Dennis R.

    2013-09-16

    The structural and chemical composition of two unique microstructures formed on nickel, with nanoscale features, produced using femtosecond laser surface processing (FLSP) techniques is reported in this paper. These two surface morphologies, termed mounds and nanoparticle-covered pyramids, are part of a larger class of self-organized micro/nanostructured surfaces formed using FLSP. Cross-sections of the structures produced using focused ion beam milling techniques were analyzed with a transmission electron microscope. Both morphologies have a solid core with a layer of nanoparticles on the surface. Energy dispersive X-ray spectroscopy by scanning transmission electron microscopy studies reveal that the nanoparticles are a nickel oxide, while the core material is pure nickel.

  18. High-performance, nanostructure LiMnPO4/C composites synthesized via one-step solid state reaction

    NASA Astrophysics Data System (ADS)

    Zheng, Jugong; Ni, Liang; Lu, Yanwen; Qin, Cancan; Liu, Panxing; Wu, Tongfu; Tang, Yuefeng; Chen, Yanfeng

    2015-05-01

    LiMnPO4 is proposed as more promising cathode material as LiFePO4, while poor electronic conductivity and Jahn-Teller effects during charge/discharge processes hinder the electrochemical performance. To overcome these problems, one-step solid state reaction method is developed to synthesize LiMnPO4/C composites, which is with nanostructure, high crystallinity and good carbon coating. Manganese oxide sources and calcination temperature are investigated as factors for preparing high-performance LiMnPO4/C for Li-ion batteries. The results show that the LiMnPO4/C composites prepared with mixed manganese oxide deliver a superior initial capacity of 153 mAh g-1 at 0.05 C and high rate performance with discharge capacities of 123 mAh g-1 at 1 C and 103 mAh g-1 at 2 C. And the LiMnPO4/C composites synthesized at 600 °C can retain 94% of the initial capacity after 200 cycles at 1 C, revealing a stable cycling stability. Therefore, one-step solid state reaction brings to light the synthesis of high performance LiMnPO4/C cathode materials and is suitable for large scale production.

  19. High-capacity nanostructured germanium-containing materials and lithium alloys thereof

    DOEpatents

    Graetz, Jason A.; Fultz, Brent T.; Ahn, Channing; Yazami, Rachid

    2010-08-24

    Electrodes comprising an alkali metal, for example, lithium, alloyed with nanostructured materials of formula Si.sub.zGe.sub.(z-1), where 0

  20. Ultrafast Photoresponsive Starburst and Dendritic Fullerenyl Nanostructures for Broadband Nonlinear Photonic Material Applications

    DTIC Science & Technology

    2014-08-20

    AFRL-OSR-VA-TR-2014-0197 ULTRAFAST PHOTORESPONSIVE STARBURST AND DENDRITIC FULLERENYL NOSTRUCTURES FOR BROADBAND NONLINEAR PHOTONIC MATERIAL...Report 3. DATES COVERED (From - To) 03-01-2009 – 05-31-2014 4. TITLE AND SUBTITLE Ultrafast Photoresponsive Starburst and Dendritic Fullerenyl...photophysical properties of ultrafast photoresponsive starburst and dendritic C60/C70-light harvesting antenna-based organic nanostructures for broadband

  1. Advanced composite materials for optomechanical systems

    NASA Astrophysics Data System (ADS)

    Zweben, Carl

    2013-09-01

    Polymer matrix composites (PMCs) have been well established in optomechanical systems for several decades. The other three classes of composites; metal matrix composites (MMCs), ceramic matrix composites (CMCs), and carbon matrix composites (CAMCs) are making significant inroads. The latter include carbon/carbon (C/C) composites (CCCs). The success of composites has resulted in increasing use in consumer, industrial, scientific, and aerospace/defense optomechanical applications. Composites offer significant advantages over traditional materials, including high stiffnesses and strengths, near-zero and tailorable coefficients of thermal expansion (CTEs), tailorable thermal conductivities (from very low to over twice that of copper), and low densities. In addition, they lack beryllium's toxicity problems. Some manufacturing processes allow parts consolidation, reducing machining and joining operations. At present, PMCs are the most widely used composites. Optomechanical applications date from the 1970s. The second High Energy Astrophysical Observatory spacecraft, placed in orbit in 1978, had an ultrahigh-modulus carbon fiber-reinforced epoxy (carbon/epoxy) optical bench metering structure. Since then, fibers and matrix materials have advanced significantly, and use of carbon fiber-reinforced polymers (CFRPs) has increased steadily. Space system examples include the Hubble Space Telescope metering truss and instrument benches, Upper Atmosphere Research Satellite (UARS), James Webb Space Telescope and many others. Use has spread to airborne applications, such as SOFIA. Perhaps the most impressive CFRP applications are the fifty-four 12m and twelve 7m moveable ground-based ALMA antennas. The other three classes of composites have a number of significant advantages over PMCs, including no moisture absorption or outgassing of organic compounds. CCC and CMC components have flown on a variety of spacecraft. MMCs have been used in space, aircraft, military and industrial

  2. Nanostructured intermetallic FeSn2-carbonaceous composites as highly stable anode for Na-ion batteries

    NASA Astrophysics Data System (ADS)

    Edison, Eldho; Satish, Rohit; Ling, Wong Chui; Bucher, Nicolas; Aravindan, Vanchiappan; Madhavi, Srinivasan

    2017-03-01

    The commercialization of Na-ion batteries demands the development of technologically feasible and economically viable electrodes, in particular anodes. Herein, we report the facile synthesis of nanostructured FeSn2 by a hydrothermal route and the formulation of composites with different carbonaceous materials like Super P, graphite, and graphene via high-throughput ball-milling. The influence of the carbonaceous matrix on the electrochemical performance of the alloy anode is investigated in half-cell assembly. Amongst, FeSn2-Graphite composite exhibits excellent cycling stability with a reversible capacity of 333 mAh g-1 obtained after 100 cycles at a specific current of 100 mA g-1. The composite also displayed a good rate performance even at high current rates of 1 A g-1 which is a desirable feature for high power applications such as hybrid electric vehicles. The outstanding electrochemical performance of the composite anodes is ascribed to the effective encapsulation of the alloy particles in the carbonaceous matrix, which sustains the volume change and facilitates excellent Na-storage capability.

  3. Sensors as probes for the environmental dynamics of nanostructured materials

    NASA Astrophysics Data System (ADS)

    Sadik, Wunmi

    2012-02-01

    The last decade has witnessed an explosion of interests in the science and technology of engineered nanomaterials. The primary drive for most nanotechnology research and development is to synthesize new nanomaterials and to identify novel applications for them. Nanomaterials offer new possibilities for the development of novel sensing and monitoring technologies. Nanosensors can be classified under two main categories: (1) sensors that are used to measure nanoscale properties; and (2) sensors that are themselves nanoscale or have nanoscale materials or components. The first category can enhance our understanding of the fate and transport of engineered nanomaterials in environmental and biological systems. This is an area of critical interest in risk assessment. The second category can eventually result in lower material cost, reduced weight and power consumption. This presentation will focus on category 1 sensor for fullerenes and metal nanoparticles.

  4. Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

    NASA Technical Reports Server (NTRS)

    Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.; Lowther, S. E.; Lillehei, P. T.; Bryant, R. G.

    2012-01-01

    Tailoring the solar absorptivity (alpha(sub s)) and thermal emissivity (epsilon(sub T)) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The alpha(sub s) and epsilon(sub T) were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the alpha(sub s) and epsilon(sub T) by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  5. Nanostructured carbon materials for adsorption of methane and other gases

    DOEpatents

    Stadie, Nicholas P.; Fultz, Brent T.; Ahn, Channing; Murialdo, Maxwell

    2015-06-30

    Provided are methods for storing gases on porous adsorbents, methods for optimizing the storage of gases on porous adsorbents, methods of making porous adsorbents, and methods of gas storage of optimized compositions, as in systems containing porous adsorbents and gas adsorbed on the surface of the porous adsorbent. The disclosed methods and systems feature a constant or increasing isosteric enthalpy of adsorption as a function of uptake of the gas onto the exposed surface of a porous adsorbent. Adsorbents with a porous geometry and surface dimensions suited to a particular adsorbate are exposed to the gas at elevated pressures in the specific regime where n/V (density) is larger than predicted by the ideal gas law by more than several percent.

  6. Tensile failure criteria for fiber composite materials

    NASA Technical Reports Server (NTRS)

    Rosen, B. W.; Zweben, C. H.

    1972-01-01

    The analysis provides insight into the failure mechanics of these materials and defines criteria which serve as tools for preliminary design material selection and for material reliability assessment. The model incorporates both dispersed and propagation type failures and includes the influence of material heterogeneity. The important effects of localized matrix damage and post-failure matrix shear stress transfer are included in the treatment. The model is used to evaluate the influence of key parameters on the failure of several commonly used fiber-matrix systems. Analyses of three possible failure modes were developed. These modes are the fiber break propagation mode, the cumulative group fracture mode, and the weakest link mode. Application of the new model to composite material systems has indicated several results which require attention in the development of reliable structural composites. Prominent among these are the size effect and the influence of fiber strength variability.

  7. Properties of five toughened matrix composite materials

    NASA Technical Reports Server (NTRS)

    Cano, Roberto J.; Dow, Marvin B.

    1992-01-01

    The use of toughened matrix composite materials offers an attractive solution to the problem of poor damage tolerance associated with advanced composite materials. In this study, the unidirectional laminate strengths and moduli, notched (open-hole) and unnotched tension and compression properties of quasi-isotropic laminates, and compression-after-impact strengths of five carbon fiber/toughened matrix composites, IM7/E7T1-2, IM7/X1845, G40-800X/5255-3, IM7/5255-3, and IM7/5260 have been evaluated. The compression-after-impact (CAI) strengths were determined primarily by impacting quasi-isotropic laminates with the NASA Langley air gun. A few CAI tests were also made with a drop-weight impactor. For a given impact energy, compression after impact strengths were determined to be dependent on impactor velocity. Properties and strengths for the five materials tested are compared with NASA data on other toughened matrix materials (IM7/8551-7, IM6/1808I, IM7/F655, and T800/F3900). This investigation found that all five materials were stronger and more impact damage tolerant than more brittle carbon/epoxy composite materials currently used in aircraft structures.

  8. Nanostructured Composite Materials for High Temperature Thermoelectric Energy Conversion

    DTIC Science & Technology

    2012-08-29

    were consolidated by both conventional hot pressing and spark plasma sintering . A detailed analysis of the x-ray diffraction pattern yields grain...measured the modulus and hardness of Ir- and Rh-substituted half-Heusler compounds consolidated hot pressing and spark - plasma sintering . The...for the entire series, Zr05Hf05NilxPdx Sno.99Sbo.01 Also shown is the comparison between the hot pressed samples (labeled HP) and spark - plasma

  9. Nanostructured Shape Memory Alloys: Adaptive Composite Materials and Components

    DTIC Science & Technology

    2007-12-01

    extension fracture boudinage. Journal of Structural Geology , vol 4, No.3, pp. 355 -372, 1982. 3. Shaocheng Ji, Pinglao Zhao. Location of tensile...Science and Engineering Center at the University of I Wisconsin - Madison and an Internships in Public Science Education grant. Research conducted

  10. Composite WO3/TiO2 nanostructures for high electrochromic activity

    SciTech Connect

    Reyes-Gil, Karla R.; Stephens, Zachary D.; Stavila, Vitalie; Robinson, David B.

    2015-01-06

    A composite material consisting of TiO2 nanotubes (NT) with WO3 electrodeposited on its surface has been fabricated, detached from its Ti substrate, and attached to a fluorine-doped tin oxide (FTO) film on glass for application to electrochromic (EC) reactions. Several adhesion layers were tested, finding that a paste of TiO2 made from commercially available TiO2 nanoparticles creates an interface for the TiO2 NT film to attach to the FTO glass, which is conductive and does not cause solution-phase ions in an electrolyte to bind irreversibly with the material. The effect of NT length and WO3 concentration on the EC performance were studied. As a result, the composite WO3/TiO2 nanostructures showed higher ion storage capacity, better stability, enhanced EC contrast, and longer memory time compared with the pure WO3 and TiO2 materials

  11. Impact testing of textile composite materials

    NASA Technical Reports Server (NTRS)

    Portanova, Marc

    1995-01-01

    The objectives of this report were to evaluate the impact damage resistance and damage tolerance of a variety of textile composite materials. Static indentation and impact tests were performed on the stitched and unstitched uniweave composites constructed from AS4/3501-6 Carbon/Epoxy with a fiberglass yarn woven in to hold the fibers together while being stitched. Compression and tension were measured after the tests to determine the damage resistance, residual strength and the damage tolerance of the specimens.

  12. New composite materials for optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Iovu, M. S.; Buzurniuc, S. A.; Verlan, V. I.; Culeac, I. P.; Nistor, Yu. H.

    2009-01-01

    The problem of obtaining low cost but efficient luminescent materials is still actually. Data concerning fabrication and luminescent properties of new composite materials on the base of thenoyltrifluoroacetone (TTA) of Europium(III) (Eu(TTA)3) and chalcogenide glasses doped with rare earth ions and polymers are presented. The visible emission spectra of the composites on the base of Eu(TTA)3 structured with phenantroline (Eu(TTA)3Phen) and copolymer from styrene and butylmethacrylate (1:1)(SBMA) under the excitation with N2-laser (λ=337 nm) contain sharp emission bands located at 354, 415, 580, 587, 590, 596, 611.4, 616.5, 621, 652, 690, 700, 713 nm. The nature of the observed emission bands and the possible mechanisms of the radiative electron transition in the investigated composite materials are discussed.

  13. Rational Design of Molecular Ferroelectric Materials and Nanostructures

    SciTech Connect

    Ducharme, Stephen

    2012-09-25

    The purpose of this project was to gain insight into the properties of molecular ferroelectrics through the detailed study of oligomer analogs of polyvinylidene fluoride (PVDF). By focusing on interactions at both the molecular level and the nanoscale level, we expect to gain improved understanding about the fundamental mechanism of ferroelectricity and its key properties. The research consisted of three complementary components: 1) Rational synthesis of VDF oligomers by Prof. Takacs' group; 2) Detailed structural and electrical studies of thin by Prof. Ducharme's Group; and 3) First-principles computational studies by DOE Lab Partner Dr. Serge Nakhman-son at Argonne National Laboratory. The main results of the work was a detailed understanding of the relationships between the molecular interactions and macroscopic phenomenology of fer-roelectricity VDF oligomers. This is valuable information supporting the development of im-proved electromechanical materials for, e.g., sonar, ultrasonic imaging, artificial muscles, and compliant actuators. Other potential applications include nonvolatile ferroelectric memories, heat-sensing imaging arrays, photovoltaic devices, and functional biomimetic materials. The pro-ject contributed to the training and professional development of undergraduate students and graduate students, post-doctoral assistants, and a high-school teacher. Project personnel took part in several outreach and education activities each year.

  14. Surface Anchoring of Nematic Phase on Carbon Nanotubes: Nanostructure of Ultra-High Temperature Materials

    SciTech Connect

    Ogale, Amod A

    2012-04-27

    consisting of strong carbon fibers embedded in a carbon matrix are needed. Such carbon/carbon (C/C) composites have been used in aerospace industry to produce missile nose cones, space shuttle leading edge, and aircraft brake-pads. However, radiation-tolerance of such materials is not adequately known because only limited radiation studies have been performed on C/C composites, which suggest that pitch-based carbon fibers have better dimensional stability than that of polyacrylonitrile (PAN) based fibers [4]. The thermodynamically-stable state of graphitic crystalline packing of carbon atoms derived from mesophase pitch leads to a greater stability during neutron irradiation [5]. The specific objectives of this project were: (i) to generating novel carbonaceous nanostructures, (ii) measure extent of graphitic crystallinity and the extent of anisotropy, and (iii) collaborate with the Carbon Materials group at Oak Ridge National Lab to have neutron irradiation studies and post-irradiation examinations conducted on the carbon fibers produced in this research project.

  15. Nanostructure and Composition of Tribo-Boundary Films Formed in Ionic Liquid Lubrication

    SciTech Connect

    Qu, Jun; Chi, Miaofang; Meyer III, Harry M; Blau, Peter Julian; Dai, Sheng; Luo, Huimin

    2011-01-01

    Since the idea of using ionic liquids (ILs) as lubricants was raised in 2001, many studies have been conducted in this area and results have demonstrated superior lubricating performance for a variety of ionic liquids. It is widely believed that tribochemical reactions occur between the metal surface and the IL during the wear process to form a protective tribo-boundary film on the contact area that reduces friction and wear. However, the study of this critical boundary film has been limited to top surface two-dimensional topography examination and chemical analysis in the literature. A more comprehensive characterization is needed to help understand the film formation process and the lubricating mechanism. This study demonstrated a multi-technique three-dimensional approach to characterize the IL-formed boundary films, including top surface morphology examination, cross section nanostructure characterization, and layered chemical analysis. Characterization was carried out on both ferrous and aluminum surfaces lubricated by an ammonium IL. The focused-ion-beam (FIB) technique enabled TEM/EDS examination on the cross section of the boundary film to provide direct measurement of the film thickness, visualization of the nanostructure, and analysis of composition. In addition, composition-depth profiles were generated using XPS aided by ion-sputtering to reveal the composition change at different levels of the boundary film to investigate the film formation process.

  16. Computational modeling of composite material fires.

    SciTech Connect

    Brown, Alexander L.; Erickson, Kenneth L.; Hubbard, Joshua Allen; Dodd, Amanda B.

    2010-10-01

    Composite materials behave differently from conventional fuel sources and have the potential to smolder and burn for extended time periods. As the amount of composite materials on modern aircraft continues to increase, understanding the response of composites in fire environments becomes increasingly important. An effort is ongoing to enhance the capability to simulate composite material response in fires including the decomposition of the composite and the interaction with a fire. To adequately model composite material in a fire, two physical model development tasks are necessary; first, the decomposition model for the composite material and second, the interaction with a fire. A porous media approach for the decomposition model including a time dependent formulation with the effects of heat, mass, species, and momentum transfer of the porous solid and gas phase is being implemented in an engineering code, ARIA. ARIA is a Sandia National Laboratories multiphysics code including a range of capabilities such as incompressible Navier-Stokes equations, energy transport equations, species transport equations, non-Newtonian fluid rheology, linear elastic solid mechanics, and electro-statics. To simulate the fire, FUEGO, also a Sandia National Laboratories code, is coupled to ARIA. FUEGO represents the turbulent, buoyantly driven incompressible flow, heat transfer, mass transfer, and combustion. FUEGO and ARIA are uniquely able to solve this problem because they were designed using a common architecture (SIERRA) that enhances multiphysics coupling and both codes are capable of massively parallel calculations, enhancing performance. The decomposition reaction model is developed from small scale experimental data including thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) in both nitrogen and air for a range of heating rates and from available data in the literature. The response of the composite material subject to a radiant heat flux boundary

  17. Photocatalytic degradation of sunscreen active ingredients mediated by nanostructured materials

    NASA Astrophysics Data System (ADS)

    Soto-Vazquez, Loraine

    Water scarcity and pollution are environmental issues with terrible consequences. In recent years several pharmaceutical and personal care products, such as sunscreen active ingredients, have been detected in different water matrices. Its recalcitrant behavior in the environment has caused controversies and generated countless questions about its safety. During this research, we employed an advanced oxidation process (photocatalysis) to degrade sunscreen active ingredients. For this study, we used a 3x3 system, evaluating three photocatalysts and three different contaminants. From the three catalysts employed, two of them were synthesized. ZnO nanoparticles were obtained using zinc acetate dihydrated as the precursor, and TiO2 nanowires were synthesized from titanium tetrachloride precursor. The third catalyst employed (namely, P25) was obtained commercially. The synthesized photocatalysts were characterized in terms of the morphology, elemental composition, crystalline structure, elemental oxidation states, vibrational modes and surface area, using SEM-EDS, XRD, XPS, Raman spectroscopy and BET measurements, respectively. The photocatalysts were employed during the study of the degradation of p-aminobenzoic acid, phenylbenzimidazole sulfonic acid, and benzophenone-4. In all the cases, at least 50% degradation was achieved. P25 showed degradation efficiencies above 90%, and from the nine systems, 7 of them degraded at least 86%.

  18. Health monitoring method for composite materials

    DOEpatents

    Watkins, Jr., Kenneth S.; Morris, Shelby J.

    2011-04-12

    An in-situ method for monitoring the health of a composite component utilizes a condition sensor made of electrically conductive particles dispersed in a polymeric matrix. The sensor is bonded or otherwise formed on the matrix surface of the composite material. Age-related shrinkage of the sensor matrix results in a decrease in the resistivity of the condition sensor. Correlation of measured sensor resistivity with data from aged specimens allows indirect determination of mechanical damage and remaining age of the composite component.

  19. Thermal expansion properties of composite materials

    NASA Technical Reports Server (NTRS)

    Johnson, R. R.; Kural, M. H.; Mackey, G. B.

    1981-01-01

    Thermal expansion data for several composite materials, including generic epoxy resins, various graphite, boron, and glass fibers, and unidirectional and woven fabric composites in an epoxy matrix, were compiled. A discussion of the design, material, environmental, and fabrication properties affecting thermal expansion behavior is presented. Test methods and their accuracy are discussed. Analytical approaches to predict laminate coefficients of thermal expansion (CTE) based on lamination theory and micromechanics are also included. A discussion is included of methods of tuning a laminate to obtain a near-zero CTE for space applications.

  20. Composite materials and method of making

    DOEpatents

    Uribe, Francisco A.; Wilson, Mahlon S.; Garzon, Fernando H.

    2009-09-15

    A method of depositing noble metals on a metal hexaboride support. The hexaboride support is sufficiently electropositive to allow noble metals to deposit spontaneously from solutions containing ionic species of such metals onto the support. The method permits the deposition of metallic films of controlled thickness and particle size at room temperature without using separate reducing agents. Composite materials comprising noble metal films deposited on such metal hexaborides are also described. Such composite materials may be used as catalysts, thermionic emitters, electrical contacts, electrodes, adhesion layers, and optical coatings.

  1. Nanostructure multilayer dielectric materials for capacitors and insulators

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.

    1998-04-21

    A capacitor is formed of at least two metal conductors having a multilayer dielectric and opposite dielectric-conductor interface layers in between. The multilayer dielectric includes many alternating layers of amorphous zirconium oxide (ZrO{sub 2}) and alumina (Al{sub 2}O{sub 3}). The dielectric-conductor interface layers are engineered for increased voltage breakdown and extended service life. The local interfacial work function is increased to reduce charge injection and thus increase breakdown voltage. Proper material choices can prevent electrochemical reactions and diffusion between the conductor and dielectric. Physical vapor deposition is used to deposit the zirconium oxide (ZrO{sub 2}) and alumina (Al{sub 2}O{sub 3}) in alternating layers to form a nano-laminate. 1 fig.

  2. Nanostructured carbon materials decorated with organophosphorus moieties: synthesis and application

    PubMed Central

    Biagiotti, Giacomo; Langè, Vittoria; Ligi, Cristina; Caporali, Stefano; Muniz-Miranda, Maurizio; Flis, Anna; Pietrusiewicz, K Michał; Ghini, Giacomo; Brandi, Alberto

    2017-01-01

    A new synthetic approach for the production of carbon nanomaterials (CNM) decorated with organophosphorus moieties is presented. Three different triphenylphosphine oxide (TPPO) derivatives were used to decorate oxidized multiwalled carbon nanotubes (ox-MWCNTs) and graphene platelets (GPs). The TPPOs chosen bear functional groups able to react with the CNMs by Tour reaction (an amino group), nitrene cycloaddition (an azido group) or CuAAC reaction (one terminal C–C triple bond). All the adducts were characterized by FTIR, Raman spectroscopy, TEM, XPS, elemental analysis and ICP-AES. The cycloaddition of nitrene provided the higher loading on ox-MWCNTs and GPs as well, while the Tour approach gave best results with nanotubes (CNTs). Finally, we investigated the possibility to reduce the TPPO functionalized CNMs to the corresponding phosphine derivatives and applied one of the materials produced as heterogeneous organocatalyst in a Staudinger ligation reaction. PMID:28326239

  3. Nanostructured material for advanced energy storage : magnesium battery cathode development.

    SciTech Connect

    Sigmund, Wolfgang M.; Woan, Karran V.; Bell, Nelson Simmons

    2010-11-01

    Magnesium batteries are alternatives to the use of lithium ion and nickel metal hydride secondary batteries due to magnesium's abundance, safety of operation, and lower toxicity of disposal. The divalency of the magnesium ion and its chemistry poses some difficulties for its general and industrial use. This work developed a continuous and fibrous nanoscale network of the cathode material through the use of electrospinning with the goal of enhancing performance and reactivity of the battery. The system was characterized and preliminary tests were performed on the constructed battery cells. We were successful in building and testing a series of electrochemical systems that demonstrated good cyclability maintaining 60-70% of discharge capacity after more than 50 charge-discharge cycles.

  4. Poly(3-hexylthiophene) nanostructured materials for organic electronics applications.

    PubMed

    Bhatt, M P; Magurudeniya, H D; Rainbolt, E A; Huang, P; Dissanayake, D S; Biewer, M C; Stefan, M C

    2014-02-01

    Semiconducting polymers have been developed during the last few decades and are currently used in various organic electronics applications. Regioregular poly(3-hexylthiophene) (P3HT) is the most employed semiconducting polymer for organic electronics applications. The development of living Grignard metathesis polymerization (GRIM) allowed the synthesis of P3HT with well-defined molecular weights and functional end groups. A large number of block copolymers containing P3HT have been reported, and their opto-electronic properties have been investigated. The performance of P3HT homopolymer and block copolymers in field-effect transistors and bulk heterojunction solar cells are discussed in this review. The morphology of the P3HT materials is also discussed.

  5. Dinuclear transition metal complexes in carbon nanostructured materials synthesis

    NASA Astrophysics Data System (ADS)

    Ayuso, J. I.; Hernández, E.; Delgado, E.

    2013-06-01

    Carbon nanomaterials (CNMs) were prepared with two similar techniques using organometallic complexes as catalysts precursors. Chemical vapour deposition (CVD) and pyrolysis with chlorine gas approaches were employed in order to explore the effect of dinuclear transition metal compounds [Fe2(CO)6(μ-S2C6H2X2), (X=OH, Cl)] in synthesis of CNMs. Our to-date results have shown these complexes generate different carbonaceous materials when they are used in bulk, it was also observed that their performances in synthesis differ even though these compounds are analogous. With X=OH complex used in CVD process, metal nanoparticles of ca. 20-50 nm in size and embedded in carbon matrix were obtained. X=C1 complex has been used in pyrolysis experiments and showed an entire volatilisation or no reaction, depending on selected temperature. Furthermore, obtaining of a new tetranuclear iron cluster is presented in this work.

  6. Nanostructure multilayer dielectric materials for capacitors and insulators

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.

    1998-04-21

    A capacitor is formed of at least two metal conductors having a multilayer dielectric and opposite dielectric-conductor interface layers in between. The multilayer dielectric includes many alternating layers of amorphous zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3). The dielectric-conductor interface layers are engineered for increased voltage breakdown and extended service life. The local interfacial work function is increased to reduce charge injection and thus increase breakdown voltage. Proper material choices can prevent electrochemical reactions and diffusion between the conductor and dielectric. Physical vapor deposition is used to deposit the zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3) in alternating layers to form a nano-laminate.

  7. Hexagonal CeO2 nanostructures: an efficient electrode material for supercapacitors.

    PubMed

    Maheswari, Nallappan; Muralidharan, Gopalan

    2016-09-28

    Cerium oxide (CeO2) has emerged as a new and promising pseudocapacitive material due to its prominent valance states and extensive applications in various fields. In the present study, hexagonal CeO2 nanostructures have been prepared via the hydrothermal method employing cationic surfactant cetyl trimethyl ammonium bromide (CTAB). CTAB ensures a slow rate of hydrolysis to form small sized CeO2 nanostructures. The role of calcination temperature on the morphological, structural, electrochemical properties and cyclic stability has been assessed for supercapacitor applications. The mesoscopic hexagonal architecture endows the CeO2 with not only a higher specific capacity, but also with an excellent rate capability and cyclability. When the charge/discharge current density is increased from 2 to 10 A g(-1) the reversible charge capacity decreased from 927 F g(-1) to 475 F g(-1) while 100% capacity retention at a high current density of 20 A g(-1) even after 1500 cycles could be achieved. Furthermore, the asymmetric supercapacitor based on CeO2 exhibited a significantly higher energy density of 45.6 W h kg(-1) at a power density of 187.5 W kg(-1) with good cyclic stability. The electrochemical richness of the CeO2 nanostructure makes it a suitable electrode material for supercapacitor applications.

  8. Ground exposure of composite materials for helicopters

    NASA Technical Reports Server (NTRS)

    Baker, D. J.

    1984-01-01

    Residual strength results are presented on four composite material systems that were exposed for three years at locations on the North American Continent. The exposure locations are near the areas where Bell Model 206L Helicopters, that are in a NSA/U.S. Army sponsored flight service program, are flying in daily commercial service. The composite systems are: (1) Kevlar-49 fabric/F-185 epoxy; (2) Kevlar-49 fabric/LRF-277 epoxy; (3) Kevlar-49 fabric/CE-306 epoxy; and (4) T-300 Graphite/E-788 epoxy. All material systems exhibited good strength retention in compression and short beam shear. The Kevlar-49/LRF-277 epoxy retained 88 to 93 percent of the baseline strength while the other material systems exceeded 95 percent of baseline strength. Residual tensile strength of all materials did not show a significant reduction. The available moisture absorption data is also presented.

  9. Frictional Ignition Testing of Composite Materials

    NASA Technical Reports Server (NTRS)

    Peralta, Steve; Rosales, Keisa; Robinson, Michael J.; Stoltzfus, Joel

    2006-01-01

    The space flight community has been investigating lightweight composite materials for use in propellant tanks for both liquid and gaseous oxygen for space flight vehicles. The use of these materials presents some risks pertaining to ignition and burning hazards in the presence of oxygen. Through hazard analysis process, some ignition mechanisms have been identified as being potentially credible. One of the ignition mechanisms was reciprocal friction; however, test data do not exist that could be used to clear or fail these types of materials as "oxygen compatible" for the reciprocal friction ignition mechanism. Therefore, testing was performed at White Sands Test Facility (WSTF) to provide data to evaluate this ignition mechanism. This paper presents the test system, approach, data results, and findings of the reciprocal friction testing performed on composite sample materials being considered for propellant tanks.

  10. Glass-ceramics: A class of nanostructured materials for photonics

    NASA Astrophysics Data System (ADS)

    de Pablos-Martin, A.; Ferrari, M.; Pascual, M. J.; Righini, G. C.

    2015-07-01

    Glass-ceramics (GCs) are constituted by nanometer-to-micron-sized crystals embedded in a glass matrix; usually, their structural or functional elements (clusters, crystallites or molecules) have dimensions in the 1 to 100nm range. As the name says, GCs must be considered an intermediate material between inorganic glasses and ceramics; in most cases the crystallinity is between 30 and 50%. GCs share many properties with both glasses and ceramics, offering low defects, extra hardness, high thermal shock resistance (typical of ceramics) together with the ease of fabrication and moulding (typical of glasses). The embedded crystalline phase, however, can enhance the existing properties of the matrix glass or lead to entirely new properties. GCs are produced by controlled crystallization of certain glasses, generally induced by nucleating additives; they may result opaque or transparent. Transparent GCs are now gaining a competitive advantage with respect to amorphous glasses and, sometimes, to crystals too. The aim of the present paper is to introduce the basic characteristics of transparent glass-ceramics, with particular attention to the relationship between structure and transparency and to the mechanism of crystallization, which may also be induced by selective laser treatments. Their applications to the development of guided-wave structures are also briefly described.

  11. MATERIALS, FABRICATION, AND MANUFACTURING OF MICRO/NANOSTRUCTURED SURFACES FOR PHASE-CHANGE HEAT TRANSFER ENHANCEMENT

    SciTech Connect

    McCarthy, M; Gerasopoulos, K; Maroo, SC; Hart, AJ

    2014-07-23

    This article describes the most prominent materials, fabrication methods, and manufacturing schemes for micro- and nanostructured surfaces that can be employed to enhance phase-change heat transfer phenomena. The numerous processes include traditional microfabrication techniques such as thin-film deposition, lithography, and etching, as well as template-assisted and template-free nanofabrication techniques. The creation of complex, hierarchical, and heterogeneous surface structures using advanced techniques is also reviewed. Additionally, research needs in the field and future directions necessary to translate these approaches from the laboratory to high-performance applications are identified. Particular focus is placed on the extension of these techniques to the design of micro/nanostructures for increased performance, manufacturability, and reliability. The current research needs and goals are detailed, and potential pathways forward are suggested.

  12. Method of making carbon nanotube composite materials

    DOEpatents

    O'Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2014-05-20

    The present invention is a method of making a composite polymeric material by dissolving a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes and optionally additives in a solvent to make a solution and removing at least a portion of the solvent after casting onto a substrate to make thin films. The material has enhanced conductivity properties due to the blending of the un-functionalized and hydroxylated carbon nanotubes.

  13. Modeling of laser interactions with composite materials

    DOE PAGES

    Rubenchik, Alexander M.; Boley, Charles D.

    2013-05-07

    In this study, we develop models of laser interactions with composite materials consisting of fibers embedded within a matrix. A ray-trace model is shown to determine the absorptivity, absorption depth, and optical power enhancement within the material, as well as the angular distribution of the reflected light. We also develop a macroscopic model, which provides physical insight and overall results. We show that the parameters in this model can be determined from the ray trace model.

  14. Multiaxial analysis of dental composite materials.

    PubMed

    Kotche, Miiri; Drummond, James L; Sun, Kang; Vural, Murat; DeCarlo, Francesco

    2009-02-01

    Dental composites are subjected to extreme chemical and mechanical conditions in the oral environment, contributing to the degradation and ultimate failure of the material in vivo. The objective of this study is to validate an alternative method of mechanically loading dental composite materials. Confined compression testing more closely represents the complex loading that dental restorations experience in the oral cavity. Dental composites, a nanofilled and a hybrid microfilled, were prepared as cylindrical specimens, light-cured in ring molds of 6061 aluminum, with the ends polished to ensure parallel surfaces. The samples were subjected to confined compression loading to 3, 6, 9, 12, and 15% axial strain. Upon loading, the ring constrains radial expansion of the specimen, generating confinement stresses. A strain gage placed on the outer wall of the aluminum confining ring records hoop strain. Assuming plane stress conditions, the confining stress (sigma(c)) can be calculated at the sample/ring interface. Following mechanical loading, tomographic data was generated using a high-resolution microtomography system developed at beamline 2-BM of the Advanced Photon Source at Argonne National Laboratory. Extraction of the crack and void surfaces present in the material bulk is numerically represented as crack edge/volume (CE/V), and calculated as a fraction of total specimen volume. Initial results indicate that as the strain level increases the CE/V increases. Analysis of the composite specimens under different mechanical loads suggests that microtomography is a useful tool for three-dimensional evaluation of dental composite fracture surfaces.

  15. New generation photoelectric converter structure optimization using nano-structured materials

    NASA Astrophysics Data System (ADS)

    Dronov, A.; Gavrilin, I.; Zheleznyakova, A.

    2014-12-01

    In present work the influence of anodizing process parameters on PAOT geometric parameters for optimizing and increasing ETA-cell efficiency was studied. During the calculations optimal geometrical parameters were obtained. Parameters such as anodizing current density, electrolyte composition and temperature, as well as the anodic oxidation process time were selected for this investigation. Using the optimized TiO2 photoelectrode layer with 3,6 μm porous layer thickness and pore diameter more than 80 nm the ETA-cell efficiency has been increased by 3 times comparing to not nanostructured TiO2 photoelectrode.

  16. Composite materials for the extravehicular mobility unit

    NASA Technical Reports Server (NTRS)

    Barrera, Enrique V.; Tello, Hector M.

    1992-01-01

    The extravehicular mobility unit (EMU), commonly known as the astronaut space suit assembly (SSA) and primary life support system (PLSS), has evolved through the years to incorporate new and innovative materials in order to meet the demands of the space environment. The space shuttle program which is seeing an increasing level of extravehicular activity (EVA), also called space walks, along with interest in an EMU for Lunar-Mars missions means even more demanding conditions are being placed on the suit and PLSS. The project for this NASA-ASEE Summer Program was to investigate new materials for these applications. The focus was to emphasize the use of composite materials for every component of the EMU to enhance the properties while reducing the total weight of the EMU. To accomplish this, development of new materials called fullerene reinforced materials (FRM's) was initiated. Fullerenes are carbon molecules which when added to a material significantly reduce the weight of that material. The Faculty Fellow worked directly on the development of the fullerene reinforced materials. A chamber for fullerene production was designed and assembled and first generation samples were processed. He also supervised with the JSC Colleague, a study of composite materials for the EMU conducted by the student participant in the NASA-ASEE Program, Hector Tello a Rice University graduate student, and by a NASA Aerospace Technologist (Materials Engineer) Evelyne Orndoff, in the Systems Engineering Analysis Office (EC7), also a Rice University graduate student. Hector Tello conducted a study on beryllium and Be alloys and initiated a study of carbon and glass reinforced composites for space applications. Evelyne Orndoff compiled an inventory of the materials on the SSA. Ms. Orndoff also reviewed SSA material requirements and cited aspects of the SSA design where composite materials might be further considered. Hector Tello spent part of his time investigating the solar radiation

  17. Composite materials for rail transit systems

    NASA Technical Reports Server (NTRS)

    Griffin, O. Hayden, Jr.; Guerdal, Zafer; Herakovich, Carl T.

    1987-01-01

    The potential is explored for using composite materials in urban mass transit systems. The emphasis was to identify specific advantages of composite materials in order to determine their actual and potential usage for carbody and guideway structure applications. The literature was reviewed, contacts were made with major domestic system operators, designers, and builders, and an analysis was made of potential composite application to railcar construction. Composites were found to be in use throughout the transit industry, usually in secondary or auxiliary applications such as car interior and nonstructural exterior panels. More recently, considerable activity has been initiated in the area of using composites in the load bearing elements of civil engineering structures such as highway bridges. It is believed that new and improved manufacturing refinements in pultrusion and filament winding will permit the production of beam sections which can be used in guideway structures. The inherent corrosion resistance and low maintenance characteristics of composites should result in lowered maintenance costs over a prolonged life of the structure.

  18. Doping in controlling the type of conductivity in bulk and nanostructured thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Fuks, D.; Komisarchik, G.; Kaller, M.; Gelbstein, Y.

    2016-08-01

    Doping of materials for thermoelectric applications is widely used nowadays to control the type of conductivity. We report the results of ab-initio calculations aimed at developing the consistent scheme for determining the role of impurities that may change the type of conductivity in two attractive thermoelectric classes of materials. It is demonstrated that alloying of TiNiSn with Cu makes the material of n-type, and alloying with Fe leads to p-type conductivity. Similar calculations for PbTe with small amount of Na substituting for Pb leads to p-type conductivity, while Cl substituting for Te makes PbTe an n-type material. It is shown also that for nano-grained materials the n-type conductivity should be observed. The effect of impurities segregating to the grain boundaries in nano-structured PbTe is also discussed.

  19. Wetting, superhydrophobicity, and icephobicity in biomimetic composite materials

    NASA Astrophysics Data System (ADS)

    Hejazi, Vahid

    data are collected in terms of oleophobicity especially when underwater applications are of interest. We develop models for four-phase rough interface of underwater oleophobicity and develop a novel approach to predict the CA of organic liquid on the rough surfaces immersed in water. We investigate wetting transition on a patterned surface in underwater systems, using a phase field model. We demonstrated that roughening on an immersed solid surface can drive the transition from Wenzel to Cassie-Baxter state. This discovery improves our understanding of underwater systems and their surface interactions during the wetting phenomenon and can be applied for the development of underwater oil-repellent materials which are of interest for various applications in the water industry, and marine devices. In chapter five, we experimentally and theoretically investigate the icephobicity of composite materials. A novel comprehensive definition of icephobicity, broad enough to cover a variety of situations including low adhesion strength, delayed ice crystallization, and bouncing is determined. Wetting behavior and ice adhesion properties of various samples are theoretically and experimentally compared. We conclude superhydrophobic surfaces are not necessarily icephobic. The models are tested against the experimental data to verify the good agreement between them. The models can be used for the design of novel superhydrophobic, oleophobic, omniphobic and icephobic composite materials. Finally we conclude that creating surface micro/nanostructures using mechanical abrasion or chemical etching as well as applying low energy materials are the most simple, inexpensive, and durable techniques to create superhydrophobic, oleophobic, and icephobic materials.

  20. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials.

    PubMed

    Kamarulzaman, Norlida; Kasim, Muhd Firdaus; Rusdi, Roshidah

    2015-12-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase. UV-visible spectroscopy showed that materials in the nanostructured state exhibit band gap widening with respect to their micron state while for the doped compounds exhibited band gap narrowing both in the nano and micron states with respect to the pure ZnO materials. The degree of band gap change was dependent on the doped elements and crystallite size. X-ray photoelectron spectroscopy (XPS) revealed that there were shifts in the valence bands. From both UV-visible and XPS spectroscopy, it was found that the mechanism for band gap narrowing was due to the shifting of the valance band maximum and conduction band minimum of the materials. The mechanisms were different for different samples depending on the type of dopant and dimensional length scales of the crystallites.

  1. Synthesis of nanostructured manganese oxides based materials and application for supercapacitor

    NASA Astrophysics Data System (ADS)

    Dung Dang, Trung; Le, Thi Thu Hang; Bich Thuy Hoang, Thi; Mai, Thanh Tung

    2015-01-01

    Manganese oxides are important materials with a variety of applications in different fields such as chemical sensing devices, magnetic devices, field-emission devices, catalysis, ion-sieves, rechargeable batteries, hydrogen storage media and microelectronics. To open up new applications of manganese oxides, novel morphologies or nanostructures are required to be developed. Via sol—gel and anodic electrodeposition methods, M (Co, Fe) doped manganese oxides were prepared. On the other hand, nanostructured (nanoparticles, nanorods and hollow nanotubes) manganese oxides were synthesized via a process including a chemical reaction with carbon nanotubes (CNTs) templates followed by heat treatment. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV) and impedance spectroscopy (EIS) were used for characterization of the prepared materials. The influence of chemical reaction conditions, heat treatment and template present on the morphology, structure, chemical and electrochemical properties of the prepared materials were investigated. Chronopotentiometry (CP) and CV results show high specific capacitance of 186.2 to 298.4 F g-1 and the charge/discharge stability of the prepared materials and the ideal pseudocapacitive behaviors were observed. These results give an opening and promising application of these materials in advanced energy storage applications.

  2. Nanostructure-based plasmon-enhanced Raman spectroscopy for surface analysis of materials

    NASA Astrophysics Data System (ADS)

    Ding, Song-Yuan; Yi, Jun; Li, Jian-Feng; Ren, Bin; Wu, De-Yin; Panneerselvam, Rajapandiyan; Tian, Zhong-Qun

    2016-06-01

    Since 2000, there has been an explosion of activity in the field of plasmon-enhanced Raman spectroscopy (PERS), including surface-enhanced Raman spectroscopy (SERS), tip-enhanced Raman spectroscopy (TERS) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). In this Review, we explore the mechanism of PERS and discuss PERS hotspots — nanoscale regions with a strongly enhanced local electromagnetic field — that allow trace-molecule detection, biomolecule analysis and surface characterization of various materials. In particular, we discuss a new generation of hotspots that are generated from hybrid structures combining PERS-active nanostructures and probe materials, which feature a strong local electromagnetic field on the surface of the probe material. Enhancement of surface Raman signals up to five orders of magnitude can be obtained from materials that are weakly SERS active or SERS inactive. We provide a detailed overview of future research directions in the field of PERS, focusing on new PERS-active nanomaterials and nanostructures and the broad application prospect for materials science and technology.

  3. Synthesis and analysis of nanostructured composite particles from gas-saturated solutions

    NASA Astrophysics Data System (ADS)

    Gil'mutdinov, I. I.; Gil'mutdinov, I. M.; Kuznetsova, I. V.; Sabirzyanov, A. N.

    2015-05-01

    Ibuprofen/polyethylene glycol 4000 and methylparaben/polyethylene glycol 4000 nanostructured composite particles are synthesized from gas-saturated solutions (PGSS, particles from gas saturated solution). The dependences of the mean size of composite particles on pressure, temperature, and the expansion channel diameter are revealed. The studies are conducted in the pressure range of 10 to 30 MPa, at temperatures ranging from 40 to 80°C, and for expansion channel diameters in the range of 200 to 500 μm. The physicochemical properties of the composite particles are investigated using a differential scanning calorimeter and phase analysis is performed by means of X-ray diffraction. The composition of composite particles is determined via mass spectrometric analysis. Chromatography-tandem mass spectrometry with electronic ionization is used for the quantitative analysis of ibuprofen, while mass spectrometry of matrix-assisted laser desorption/ionization (MALDI) is used in the analysis of polyethylene glycol 4000. The dependence of the concentration of components in composite particles on pressure is obtained.

  4. Slow crack propagation in composite restorative materials.

    PubMed

    Montes-G, G M; Draughn, R A

    1987-05-01

    The double-torsion test technique was used to study slow crack propagation in a set of dental composite resins including two glass-filled and two microfilled materials. The microstructure within each pair was the same but one of the resins was selfcured and the other photocured. The fracture behavior was dependent on the filler concentration and the presence of absorbed water. Wet materials fractured by slow crack growth in the range of crack velocity studied (10(-7) to 10(-3) m/s), and the microfilled composites, which contain a lower concentration of inorganic filler, had lower stress intensity factors (K1c) than the glass-filled composites tested. Dry specimens of the microfilled materials and the selfcured, glass-filled composite also showed unstable, stick-slip fracture behavior indicative of a crack blunting mechanism which leads to an elevation of the stress intensity factor for crack initiation over K1c for stable crack growth. The plasticizing effect of water increased the viscoelastic response of the materials measured by the slope of curves of slow crack growth. Analysis of fracture surfaces showed that cracks propagated at low velocities (10(-7) to 10(-5) m/s) by the apparent failure of the filler/matrix interfacial bond, and absorbed water affected the strength or fracture resistance of the interface. At high crack velocities the properties of the composite depend on the properties of the polymeric matrix, the filler, and the filler volume fraction, but at low velocities the interface is the controlling factor in the durability of these composites exposed to an aqueous environment.

  5. Nanostructured MoS2/BiVO4 Composites for Energy Storage Applications

    PubMed Central

    Arora, Yukti; Shah, Amit P.; Battu, Shateesh; Maliakkal, Carina B.; Haram, Santosh; Bhattacharya, Arnab; Khushalani, Deepa

    2016-01-01

    We report the optimized synthesis and electrochemical characterization of a composite of few-layered nanostructured MoS2 along with an electroactive metal oxide BiVO4. In comparison to pristine BiVO4, and a composite of graphene/BiVO4, the MoS2/BiVO4 nanocomposite provides impressive values of charge storage with longer discharge times and improved cycling stability. Specific capacitance values of 610 Fg−1 (170 mAhg−1) at 1 Ag−1 and 166 Fg−1 (46 mAhg−1) at 10 Ag−1 were obtained for just 2.5 wt% MoS2 loaded BiVO4. The results suggest that the explicitly synthesized small lateral-dimensioned MoS2 particles provide a notable capacitive component that helps augment the specific capacitance. We discuss the optimized synthesis of monoclinic BiVO4, and few-layered nanostructured MoS2. We report the discharge capacities and cycling performance of the MoS2/BiVO4 nanocomposite using an aqueous electrolyte. The data obtained shows the MoS2/BiVO4 nanocomposite to be a promising candidate for supercapacitor energy storage applications. PMID:27808122

  6. Nanostructured MoS2/BiVO4 Composites for Energy Storage Applications

    NASA Astrophysics Data System (ADS)

    Arora, Yukti; Shah, Amit P.; Battu, Shateesh; Maliakkal, Carina B.; Haram, Santosh; Bhattacharya, Arnab; Khushalani, Deepa

    2016-11-01

    We report the optimized synthesis and electrochemical characterization of a composite of few-layered nanostructured MoS2 along with an electroactive metal oxide BiVO4. In comparison to pristine BiVO4, and a composite of graphene/BiVO4, the MoS2/BiVO4 nanocomposite provides impressive values of charge storage with longer discharge times and improved cycling stability. Specific capacitance values of 610 Fg‑1 (170 mAhg‑1) at 1 Ag‑1 and 166 Fg‑1 (46 mAhg‑1) at 10 Ag‑1 were obtained for just 2.5 wt% MoS2 loaded BiVO4. The results suggest that the explicitly synthesized small lateral-dimensioned MoS2 particles provide a notable capacitive component that helps augment the specific capacitance. We discuss the optimized synthesis of monoclinic BiVO4, and few-layered nanostructured MoS2. We report the discharge capacities and cycling performance of the MoS2/BiVO4 nanocomposite using an aqueous electrolyte. The data obtained shows the MoS2/BiVO4 nanocomposite to be a promising candidate for supercapacitor energy storage applications.

  7. Accelerated Aging of Polymer Composite Bridge Materials

    SciTech Connect

    Carlson, Nancy Margaret; Blackwood, Larry Gene; Torres, Lucinda Laine; Rodriguez, Julio Gallardo; Yoder, Timothy Scott

    1999-03-01

    Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  8. A Flexible Nanostructured Paper of a Reduced Graphene Oxide-Sulfur Composite for High-Performance Lithium-Sulfur Batteries with Unconventional Configurations.

    PubMed

    Cao, Jun; Chen, Chen; Zhao, Qing; Zhang, Ning; Lu, Qiongqiong; Wang, Xinyu; Niu, Zhiqiang; Chen, Jun

    2016-11-01

    Flexible nanostructured reduced graphene oxide-sulfur (rGO-S) composite films are fabricated by synchronously reducing and assembling GO sheets with S nanoparticles on a metal surface. The nanostructured architecture in such composite films not only provides effective pathways for electron transport, but also suppresses the diffusion of polysulfides. Furthermore, they can serve as the cathodes of flexible Li-S batteries.

  9. Carbon Nanotube Composites: Strongest Engineering Material Ever?

    NASA Technical Reports Server (NTRS)

    Mayeaux, Brian; Nikolaev, Pavel; Proft, William; Nicholson, Leonard S. (Technical Monitor)

    1999-01-01

    The primary goal of the carbon nanotube project at Johnson Space Center (JSC) is to fabricate structural materials with a much higher strength-to-weight ratio than any engineered material today, Single-wall nanotubes present extraordinary mechanical properties along with new challenges for materials processing. Our project includes nanotube production, characterization, purification, and incorporation into applications studies. Now is the time to move from studying individual nanotubes to applications work. Current research at JSC focuses on structural polymeric materials to attempt to lower the weight of spacecraft necessary for interplanetary missions. These nanoscale fibers present unique new challenges to composites engineers. Preliminary studies show good nanotube dispersion and wetting by the epoxy materials. Results of tensile strength tests will also be reported. Other applications of nanotubes are also of interest for energy storage, gas storage, nanoelectronics, field emission, and biomedical uses.

  10. Composite materials for precision space reflector panels

    NASA Technical Reports Server (NTRS)

    Tompkins, Stephen S.; Funk, Joan G.; Bowles, David E.; Towell, Timothy W.; Connell, John W.

    1992-01-01

    One of the critical technology needs of large precision reflectors for future astrophysical and optical communications satellites lies in the area of structural materials. Results from a materials research and development program at NASA Langley Research Center to provide materials for these reflector applications are discussed. Advanced materials that meet the reflector panel requirements are identified, and thermal, mechanical and durability properties of candidate materials after exposure to simulated space environments are compared. A parabolic, graphite-phenolic honeycomb composite panel having a surface accuracy of 70.8 microinches rms and an areal weight of 1.17 lbm/sq ft was fabricated with T50/ERL1962 facesheets, a PAEI thermoplastic surface film, and Al and SiO(x) coatings.

  11. Localized Programmable Gas Phase Electrodeposition Yielding Functional Nanostructured Materials and Molecular Arrays

    NASA Astrophysics Data System (ADS)

    Lin, En-Chiang

    This thesis focuses on nanomanufacturing processes for the heterogeneous integration of nanomaterials and molecules. We demonstrate and discovered a novel gas phase method to control material flux at specific points on a surface which is based on the interplay of high mobility gas ions and lower mobility nanoparticles and molecules in the presence of a patterned substrate. The thesis is divided into two parts describing applications of the discovered process for the localized deposition of (A) metallic and semiconducting particles producing functional nanostructured deposits including multimaterial sensor arrays and nanostructured electrodes for photovoltaic applications and, (B) molecules for gas sensor application demonstrating improved collection efficiencies and sensitivity over previously methods. Section (A) begins with the description of an arc discharge based method to produce a flux of charged nanoparticles (<5nm particles Au, Ag, Pt, W, TiO2, ZnO and Ge) which are characterized using various methods. It then describes a process to locally deposit the charged particles into extended two and three dimensional metallic and semiconducting nanostructured deposits. The thesis describes the use externally-biased electrodes to achieve an electronic shutter to turn ON/OFF the deposition in selected domains. Subsequently it explores and describes the use of patterned dielectrics whereby the patterned dielectrics are charged to define arrays of electrodynamic lenses. Incorporation of these lensing structures was found to enable nanostructured deposits with sub 100nm lateral resolution. The utility of the discovered processes are demonstrated in two areas. For the first application, semiconducting nanomaterial are sequentially deposited on the same substrate to fabricate a multi-material/multi-functional sensor array on a single substrate in a single deposition process. The process eliminates critical alignment and masking steps and has a higher material efficiency

  12. Nanostructured SnO2-ZnO composite gas sensors for selective detection of carbon monoxide.

    PubMed

    Chesler, Paul; Hornoiu, Cristian; Mihaiu, Susana; Vladut, Cristina; Calderon Moreno, Jose Maria; Anastasescu, Mihai; Moldovan, Carmen; Firtat, Bogdan; Brasoveanu, Costin; Muscalu, George; Stan, Ion; Gartner, Mariuca

    2016-01-01

    A series of SnO2-ZnO composite nanostructured (thin) films with different amounts of SnO2 (from 0 to 50 wt %) was prepared and deposited on a miniaturized porous alumina transducer using the sol-gel and dip coating method. The transducer, developed by our research group, contains Au interdigital electrodes on one side and a Pt heater on the other side. The sensing films were characterized using SEM and AFM techniques. Highly toxic and flammable gases (CO, CO2, CH4, and C3H8) were tested under lab conditions (carrier gas was dry air) using a special gas sensing cell developed by our research group. The gas concentrations varied between 5 and 2000 ppm and the optimum working temperatures were in the range of 210-300 °C. It was found that the sensing performance was influenced by the amount of oxide components present in the composite material. Improved sensing performance was achieved for the ZnO (98 wt %)-SnO2 (2 wt %) composite as compared to the sensors containing only the pristine oxides. The sensor response, cross-response and recovery characteristics of the analyzed materials are reported. The high sensitivity (RS = 1.21) to low amounts of CO (5 ppm) was reported for the sensor containing a composite sensitive film with ZnO (98 wt %)-SnO2 (2 wt %). This sensor response to CO was five times higher as compared to its response to CO2, CH4, and C3H8, thus the sensor is considered to be selective for CO under these test conditions.

  13. Nanostructured SnO2–ZnO composite gas sensors for selective detection of carbon monoxide

    PubMed Central

    Chesler, Paul; Mihaiu, Susana; Vladut, Cristina; Calderon Moreno, Jose Maria; Anastasescu, Mihai; Moldovan, Carmen; Firtat, Bogdan; Brasoveanu, Costin; Muscalu, George; Stan, Ion; Gartner, Mariuca

    2016-01-01

    A series of SnO2–ZnO composite nanostructured (thin) films with different amounts of SnO2 (from 0 to 50 wt %) was prepared and deposited on a miniaturized porous alumina transducer using the sol–gel and dip coating method. The transducer, developed by our research group, contains Au interdigital electrodes on one side and a Pt heater on the other side. The sensing films were characterized using SEM and AFM techniques. Highly toxic and flammable gases (CO, CO2, CH4, and C3H8) were tested under lab conditions (carrier gas was dry air) using a special gas sensing cell developed by our research group. The gas concentrations varied between 5 and 2000 ppm and the optimum working temperatures were in the range of 210–300 °C. It was found that the sensing performance was influenced by the amount of oxide components present in the composite material. Improved sensing performance was achieved for the ZnO (98 wt %)–SnO2 (2 wt %) composite as compared to the sensors containing only the pristine oxides. The sensor response, cross-response and recovery characteristics of the analyzed materials are reported. The high sensitivity (R S = 1.21) to low amounts of CO (5 ppm) was reported for the sensor containing a composite sensitive film with ZnO (98 wt %)–SnO2 (2 wt %). This sensor response to CO was five times higher as compared to its response to CO2, CH4, and C3H8, thus the sensor is considered to be selective for CO under these test conditions. PMID:28144552

  14. Immobilization of lipase and keratinase on functionalized SBA-15 nanostructured materials

    NASA Astrophysics Data System (ADS)

    Le, Hy G.; Vu, Tuan A.; Tran, Hoa T. K.; Dang, Phuong T.

    2013-12-01

    SBA-15 nanostructured materials were synthesized via hydrothermal treatment and were functionalized with 3- aminopropyltriethoxysilane (APTES). The obtained samples were characterized by different techniques such as XRD, BET, TEM, IR and DTA. After functionalization, it showed that these nanostrucrured materials still maintained the hexagonal pore structure of the parent SBA-15. The model enzyms chosen in this study were lipase and keratinase. Lipase was a biocatalyst for hydrolyzation of long chain triglycerides or methyl esters of long chain alcohols and fatty acids; keratinase is a proteolytic enzyme that catalyzes the cleavage of keratin. The functionalized SBA-15 materials were used to immobilize lipase and keratinase, exhibiting higher activity than that of the unfunctionalized pure silica SBA-15 ones. This might be due to the enhancing of surface hydrophobicity upon functionalization. The surface functionalization of the nanostructured silicas with organic groups can favor the interaction between enzyme and the supports and consequently increasing the operational stability of the immobilized enzymes. The loading of lipase on functionalized SBA-15 materials was higher than that of keratinase. This might be rationalized by the difference in size of enzyms.

  15. Compression Testing of Textile Composite Materials

    NASA Technical Reports Server (NTRS)

    Masters, John E.

    1996-01-01

    The applicability of existing test methods, which were developed primarily for laminates made of unidirectional prepreg tape, to textile composites is an area of concern. The issue is whether the values measured for the 2-D and 3-D braided, woven, stitched, and knit materials are accurate representations of the true material response. This report provides a review of efforts to establish a compression test method for textile reinforced composite materials. Experimental data have been gathered from several sources and evaluated to assess the effectiveness of a variety of test methods. The effectiveness of the individual test methods to measure the material's modulus and strength is determined. Data are presented for 2-D triaxial braided, 3-D woven, and stitched graphite/epoxy material. However, the determination of a recommended test method and specimen dimensions is based, primarily, on experimental results obtained by the Boeing Defense and Space Group for 2-D triaxially braided materials. They evaluated seven test methods: NASA Short Block, Modified IITRI, Boeing Open Hole Compression, Zabora Compression, Boeing Compression after Impact, NASA ST-4, and a Sandwich Column Test.

  16. Nanostructured Materials

    DTIC Science & Technology

    2012-08-30

    B-1 APPENDIX C: ANGEWANDTE CHEMIE, INTERNATIONAL EDITION ARTICLE ......... C-1 APPENDIX D: SCIENCE... ARTICLE ........................................................................................ D-1 ii LIST OF FIGURES Figure 1. Generalized...functionality. Appendices C and D contain copies of two recent refereed journal articles on the synthesis of FluoroPOSS and the incorporation of

  17. Nanostructured Materials

    DTIC Science & Technology

    2005-08-01

    technology transfers resulted from this work, including POSS-based dental adhesives, improved plastic food packaging, and fire-retardant plastics. Several... Polydimethylsiloxanes Modified With Polyhedral Oligomeric Silsesquioxanes: From Viscous Oils To Thermoplastics”, ACS National Conference, U.S.A, 1998, ADA397983...Cyclosiloxane”, American Chemical Society Conference, U.S.A, 2001, ADA410685. Haddad, T.S.; Lee, A.; Phillips, S.H., “ Polydimethylsiloxanes Modified With

  18. Meso-scale imaging of composite materials

    SciTech Connect

    Grandin, R.; Gray, J.

    2015-03-31

    The performance of composite materials is controlled by the interaction between the individual components as well as the mechanical characteristics of the components themselves. Geometric structure on the meso-scale, where the length-scales are of the same order as the material granularity, plays a key role in controlling material performance and having a quantitative means of characterizing this structure is crucial in developing our understanding of NDE technique signatures of early damage states. High-resolution computed tomography (HRCT) provides an imaging capability which can resolve these structures for many composite materials. Coupling HRCT with three-dimensional physics-based image processing enables quantitative characterization of the meso-scale structure. Taking sequences of these damage states provides a means to structurally observe the damages evolution. We will discuss the limits of present 3DCT capability and challenges for improving this means to rapidly generate structural information of a composite and of the damage. In this presentation we will demonstrate the imaging capability of HRCT.

  19. Sub-parts per million NO2 chemi-transistor sensors based on composite porous silicon/gold nanostructures prepared by metal-assisted etching.

    PubMed

    Sainato, Michela; Strambini, Lucanos Marsilio; Rella, Simona; Mazzotta, Elisabetta; Barillaro, Giuseppe

    2015-04-08

    Surface doping of nano/mesostructured materials with metal nanoparticles to promote and optimize chemi-transistor sensing performance represents the most advanced research trend in the field of solid-state chemical sensing. In spite of the promising results emerging from metal-doping of a number of nanostructured semiconductors, its applicability to silicon-based chemi-transistor sensors has been hindered so far by the difficulties in integrating the composite metal-silicon nanostructures using the complementary metal-oxide-semiconductor (CMOS) technology. Here we propose a facile and effective top-down method for the high-yield fabrication of chemi-transistor sensors making use of composite porous silicon/gold nanostructures (cSiAuNs) acting as sensing gate. In particular, we investigate the integration of cSiAuNs synthesized by metal-assisted etching (MAE), using gold nanoparticles (NPs) as catalyst, in solid-state junction-field-effect transistors (JFETs), aimed at the detection of NO2 down to 100 parts per billion (ppb). The chemi-transistor sensors, namely cSiAuJFETs, are CMOS compatible, operate at room temperature, and are reliable, sensitive, and fully recoverable for the detection of NO2 at concentrations between 100 and 500 ppb, up to 48 h of continuous operation.

  20. Template synthesis and characterization of nanostructured lithium insertion electrodes and nanogold/porous aluminum oxide composite membranes

    NASA Astrophysics Data System (ADS)

    Patrissi, Charles John

    A membrane-based template synthesis method was used to prepare nanostructured Li-ion battery electrodes and nanogold/porous aluminum oxide composite membranes. Membrane-based template synthesis is a general method for the preparation of nanomaterials which entails deposition of the material of interest, or a suitable precursor, within the nanometer-diameter pores in a porous template membrane. This method allows for control of nanoparticle size and shape and is compatible with many methods of synthesis for bulk materials. The template membranes used in this work were commercially available porous polycarbonate filtration membranes and nanoporous aluminum oxide membranes that were prepared in-house. Nanostructured electrodes of orthorhombic V2O5, prepared using membrane-based template synthesis, were used to investigate the effects of Li-ion diffusion distance and V2O5 surface area on electrode rate capability. Nanowires of V2O5 were prepared by depositing a precursor in the pores of microporous polycarbonate filtration membranes. The result was an ensemble of 115 nm diameter, 2 mum long nanowires of V2O5 which protruded from a V 2O5 surface layer like the bristles of a brush. The Li + storage capacity of the nanostructured electrode was compared to a thin film control electrode at high discharge rates. Results show that the nanostructured electrode delivered three to four times the capacity of the thin film electrode at discharge rates above 500 C. A membrane based template synthesis method was also used to prepare crystalline V2O5 electrodes which have high volumetric charge capacities, at high discharge rates, compared to a thin-film control electrode. In order to obtain high volumetric rate capability, the as-received polycarbonate template membranes were chemically etched to increase membrane porosity. Nanofibrous electrodes of crystalline V2O5 were then prepared by depositing an alkoxide precursor in the pores of the etched membranes. Electrode volumetric