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Sample records for functional nanostructured materials

  1. 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.

  2. Self-assembled peptide nanostructures for functional materials.

    PubMed

    Ekiz, Melis Sardan; Cinar, Goksu; Khalily, Mohammad Aref; 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. PMID:27578525

  3. Self-assembled peptide nanostructures for functional materials.

    PubMed

    Ekiz, Melis Sardan; Cinar, Goksu; Khalily, Mohammad Aref; 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.

  4. Micro-/nanostructured multicomponent molecular materials: design, assembly, and functionality.

    PubMed

    Yan, Dongpeng

    2015-03-23

    Molecule-based micro-/nanomaterials have attracted considerable attention because their properties can vary greatly from the corresponding macro-sized bulk systems. Recently, the construction of multicomponent molecular solids based on crystal engineering principles has emerged as a promising alternative way to develop micro-/nanomaterials. Unlike single-component materials, the resulting multicomponent systems offer the advantages of tunable composition, and adjustable molecular arrangement, and intermolecular interactions within their solid states. The study of these materials also supplies insight into how the crystal structure, molecular components, and micro-/nanoscale effects can influence the performance of molecular materials. In this review, we describe recent advances and current directions in the assembly and applications of crystalline multicomponent micro-/nanostructures. Firstly, the design strategies for multicomponent systems based on molecular recognition and crystal engineering principles are introduced. Attention is then focused on the methods of fabrication of low-dimensional multicomponent micro-/nanostructures. Their new applications are also outlined. Finally, we briefly discuss perspectives for the further development of these molecular crystalline micro-/nanomaterials.

  5. 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

  6. 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

  7. Nanostructured composite reinforced material

    DOEpatents

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

    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.

  8. 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.

  9. 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.

  10. Self-assembly strategies for the synthesis of functional nanostructured materials

    NASA Astrophysics Data System (ADS)

    Perego, M.; Seguini, G.

    2016-06-01

    Self-assembly is the autonomous organization of components into patterns or structures without human intervention. This is the approach followed by nature to generate living cells and represents one of the practical strategies to fabricate ensembles of nanostructures. In static self-assembly the formation of ordered structures could require energy but once formed the structures are stable. The introduction of additional regular features in the environment could be used to template the self-assembly guiding the organization of the components and determining the final structure they form. In this regard self-assembly of block copolymers represents a potent platform for fundamental studies at the nanoscale and for application-driven investigation as a tool to fabricate functional nanostructured materials. Block copolymers can hierarchically assemble into chemically distinct domains with size and periodicity on the order of 10nm or below, offering a potentially inexpensive route to generate large-area nanostructured materials. The final structure characteristics of these materials are dictated by the properties of the elementary block copolymers, like chain length, volume fraction or degree of block incompatibility. Modern synthetic chemistry offers the possibility to design these macromolecules with very specific length scales and geometries, directly embodying in the block copolymers the code that drives their self- assembling process. The understanding of the kinetics and thermodynamics of the block copolymer self-assembly process in the bulk phase as well as in thin films represents a fundamental prerequisite toward the exploitation of these materials. Incorporating block copolymer into device fabrication procedures or directly into devices, as active elements, will lead to the development of a new generation of devices fabricated using the fundamental law of nature to our advantage in order to minimize cost and power consumption in the fabrication process

  11. 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.

  12. 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.

  13. 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

  14. Comparative study on functionalized SBA-15 and SBA-16 nanostructured materials used for immobilization of D-amino acid oxidase

    NASA Astrophysics Data System (ADS)

    Hy, Le Gia; Phuong, Dang Tuyet; Yen, Hoang; Hoan, Nguyen Thi Vuong; Linh, Bui Thi Hai; Thang, Hoang vinh; Hoa, Tran Thi Kim; Thang, Dinh Cao; Nguyen, Vu Thi Hanh; Thao, Phan Thi Hong; Giap, Chu Van; Tuan, Vu Anh

    2008-12-01

    SBA-15 and SBA-16 nanostucrured materials were synthesized via hydrothermal treatment and were functionalized with 3-aminopropyltriethoxysilane (APTES), and vinyltriethoxysilane (VTES). The obtained samples were characterized by different techniques such as XRD, BET, IR and TEM. After functionalization, it showed that these nanostrucrured materials were still maintained the hexagonal pore structure of the parent SBA-15 and cubic cage structure of the parent SBA-16. The non-functionalized pure silica SBA-15 and SBA-16 as well as functionalized SBA-15 and SBA-16 materials were used to immobilize DAAO, which is industrially important enzyme for the production of glutaryl 7-amino cephalosporanic acid (GL-7-ACA) from cephalosporin C (CPC). The obtained results revealed that functionalized SBA- 15 and SBA-16 materials exhibited higher enzymatic activity and stability than those of non-functionalized ones. This might be due to the enhancing of surface hydrophobicity upon functionalization. The surface functionalization of the nanostructured silicas with organic groups can enhance the interaction between enzyme and the supports and consequently increasing the operational stability of the immobilized enzyme. The loading of enzyme on SBA-15 materials was higher than that on SBA-16 samples (both functionalized and non-functionalized types). This might be explained by the difference in pore size and type (cylindrical for SBA-15 and bottle-neck for SBA-16) as well as structure shape (hexagonal for SBA-15 and cubic cage for SBA-16) of both mesoporous materials. Additionally, nature of functionalized groups significantly affected the enzymatic activity. Effects on surface binding force, nature of functional groups, pore size of supports were investigated and discussed.

  15. Nanostructured materials for water desalination.

    PubMed

    Humplik, T; Lee, J; O'Hern, S C; Fellman, B A; Baig, M A; Hassan, S F; Atieh, M A; Rahman, F; Laoui, T; Karnik, R; Wang, E N

    2011-07-22

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

  16. Nanostructured materials for water desalination

    NASA Astrophysics Data System (ADS)

    Humplik, T.; Lee, J.; O'Hern, S. C.; Fellman, B. A.; Baig, M. A.; Hassan, S. F.; Atieh, M. A.; Rahman, F.; Laoui, T.; Karnik, R.; Wang, E. N.

    2011-07-01

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

  17. 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.

  18. 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.

  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 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.

  1. 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

  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. Coupled quantum-scattering modeling of thermoelectric performance of nanostructured materials using the non-equilibrium Green's function method

    NASA Astrophysics Data System (ADS)

    Bulusu, Anuradha

    Semi-classical transport models based on Boltzmann and Fermi-Dirac statistics have been very effective identifying the pertinent physical parameters responsible for thermoelectric performance in bulk materials. Reliance on Boltzmann-based models has produced a culture of "smaller is better" research, where the reduction in size is expected to produce limitless increase in performance. Experimental observations especially in the case of thermoelectric performance of nanoscale devices have not exhibited this behavior. The semi-classical Boltzmann models are based on the relaxation-time approximation and cannot model strong non-equilibrium transport. In addition, wave effects in these models are included through correction terms that cannot suitably capture their influence on transport. A coupled quantum-scattering model to study thermoelectric performance of nanoscale structures is proposed through the nonequilibrium Green's function method. The model includes all the pertinent physics of the wave nature of electrons while coupling election-phonon scattering effects. The NEGF method is used to study the performance of silicon nano-films and nanowires as well as strained quantum well Si/Ge/Si superlattices as a function of doping, effective mass and in the case of superlattices, substrate strain and superlattice geometry. Results suggest that the power factor of nanostructured materials is dominated by the electrical conductivity which in turn is strongly influenced by quantum confinement effects and electron-phonon scattering effects. No significant improvement in the Seebeck coefficient is observed due to the decrease in dimensionality of the structure. The NEGF method can be used as a tool to design structure with optimized values of doping, effective mass, substrate strain and superlattice geometry taking into consideration the effects of electron confinement and scattering. The method developed in this research can be used as a framework to guide further studies

  5. 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.

  6. 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.

  7. Nanostructured carbonaceous materials from molecular precursors.

    PubMed

    Hoheisel, Tobias N; Schrettl, Stephen; Szilluweit, Ruth; Frauenrath, Holger

    2010-09-01

    Nanostructured carbonaceous materials, that is, carbon materials with a feature size on the nanometer scale and, in some cases, functionalized surfaces, already play an important role in a wide range of emerging fields, such as the search for novel energy sources, efficient energy storage, sustainable chemical technology, as well as organic electronic materials. Furthermore, such materials might offer solutions to the challenges associated with the on-going depletion of nonrenewable energy resources or climate change, and they may promote further breakthroughs in the field of microelectronics. However, novel methods for their preparation will be required that afford functional carbon materials with controlled surface chemistry, mesoscopic morphology, and microstructure. A highly promising approach for the synthesis of such materials is based on the use of well-defined molecular precursors. PMID:20661971

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. Chemistry and Processing of Nanostructured Materials

    SciTech Connect

    Fox, G A; Baumann, T F; Hope-Weeks, L J; Vance, A L

    2002-01-18

    Nanostructured materials can be formed through the sol-gel polymerization of inorganic or organic monomer systems. For example, a two step polymerization of tetramethoxysilane (TMOS) was developed such that silica aerogels with densities as low as 3 kg/m{sup 3} ({approx} two times the density of air) could be achieved. Organic aerogels based upon resorcinol-formaldehyde and melamine-formaldehyde can also be prepared using the sol-gel process. Materials of this type have received significant attention at LLNL due to their ultrafine cell sizes, continuous porosity, high surface area and low mass density. For both types of aerogels, sol-gel polymerization depends upon the transformation of these monomers into nanometer-sized clusters followed by cross-linking into a 3-dimensional gel network. While sol-gel chemistry provides the opportunity to synthesize new material compositions, it suffers from the inability to separate the process of cluster formation from gelation. This limitation results in structural deficiencies in the gel that impact the physical properties of the aerogel, xerogel or nanocomposite. In order to control the properties of the resultant gel, one should be able to regulate the formation of the clusters and their subsequent cross-linking. Towards this goal, we are utilizing dendrimer chemistry to separate the cluster formation from the gelation so that new nanostructured materials can be produced. Dendrimers are three-dimensional, highly branched macromolecules that are prepared in such a way that their size, shape and surface functionality are readily controlled. The dendrimers will be used as pre-formed clusters of known size that can be cross-linked to form an ordered gel network.

  14. Bioinspired Functional Materials

    SciTech Connect

    Zheng, Yongmei; Wang, Jingxia; Hou, Yongping; Bai, Hao; Hu, Michael Z.

    2014-11-25

    This special issue is focused on the nanoscale or micro-/nanoscale structures similar to the biological features in multilevels or hierarchy and so on. Research by mimicking biological systems has shown more impact on many applications due to the well-designed micro-/nanostructures inspired from the biological surfaces or interfaces; therefore, the materials may achieve the fascinating functionality. In conclusion, the bioinspired functional materials may be fabricated by developing novel technology or methods such as synthesis, self-assembly, and soft lithography at micro- or nanolevel or multilevels and, in addition, the multidisciplinary procedures of physical or chemical methods and nanotechnology to mimic the biological multiscale micro-/nanostructures onto one-/two-dimensional surface materials.

  15. Bioinspired Functional Materials

    DOE PAGESBeta

    Zheng, Yongmei; Wang, Jingxia; Hou, Yongping; Bai, Hao; Hu, Michael Z.

    2014-11-25

    This special issue is focused on the nanoscale or micro-/nanoscale structures similar to the biological features in multilevels or hierarchy and so on. Research by mimicking biological systems has shown more impact on many applications due to the well-designed micro-/nanostructures inspired from the biological surfaces or interfaces; therefore, the materials may achieve the fascinating functionality. In conclusion, the bioinspired functional materials may be fabricated by developing novel technology or methods such as synthesis, self-assembly, and soft lithography at micro- or nanolevel or multilevels and, in addition, the multidisciplinary procedures of physical or chemical methods and nanotechnology to mimic the biologicalmore » multiscale micro-/nanostructures onto one-/two-dimensional surface materials.« less

  16. Boron Nitride Nanostructures: Fabrication, Functionalization and Applications.

    PubMed

    Yin, Jun; Li, Jidong; Hang, Yang; Yu, Jin; Tai, Guoan; Li, Xuemei; Zhang, Zhuhua; Guo, Wanlin

    2016-06-01

    Boron nitride (BN) structures are featured by their excellent thermal and chemical stability and unique electronic and optical properties. However, the lack of controlled synthesis of quality samples and the electrically insulating property largely prevent realizing the full potential of BN nanostructures. A comprehensive overview of the current status of the synthesis of two-dimensional hexagonal BN sheets, three dimensional porous hexagonal BN materials and BN-involved heterostructures is provided, highlighting the advantages of different synthetic methods. In addition, structural characterization, functionalizations and prospective applications of hexagonal BN sheets are intensively discussed. One-dimensional BN nanoribbons and nanotubes are then discussed in terms of structure, fabrication and functionality. In particular, the existing routes in pursuit of tunable electronic and magnetic properties in various BN structures are surveyed, calling upon synergetic experimental and theoretical efforts to address the challenges for pioneering the applications of BN into functional devices. Finally, the progress in BN superstructures and novel B/N nanostructures is also briefly introduced. PMID:27073174

  17. 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.

  18. 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.

  19. Engineering DNA self-assemblies as templates for functional nanostructures.

    PubMed

    Wang, Zhen-Gang; Ding, Baoquan

    2014-06-17

    CONSPECTUS: DNA is a well-known natural molecule that carries genetic information. In recent decades, DNA has been used beyond its genetic role as a building block for the construction of engineering materials. Many strategies, such as tile assembly, scaffolded origami and DNA bricks, have been developed to design and produce 1D, 2D, and 3D architectures with sophisticated morphologies. Moreover, the spatial addressability of DNA nanostructures and sequence-dependent recognition enable functional elements to be precisely positioned and allow for the control of chemical and biochemical processes. The spatial arrangement of heterogeneous components using DNA nanostructures as the templates will aid in the fabrication of functional materials that are difficult to produce using other methods and can address scientific and technical challenges in interdisciplinary research. For example, plasmonic nanoparticles can be assembled into well-defined configurations with high resolution limit while exhibiting desirable collective behaviors, such as near-field enhancement. Conducting metallic or polymer patterns can be synthesized site-specifically on DNA nanostructures to form various controllable geometries, which could be used for electronic nanodevices. Biomolecules can be arranged into organized networks to perform programmable biological functionalities, such as distance-dependent enzyme-cascade activities. DNA nanostructures can carry multiple cytoactive molecules and cell-targeting groups simultaneously to address medical issues such as targeted therapy and combined administration. In this Account, we describe recent advances in the functionalization of DNA nanostructures in different fashions based on our research efforts in nanophotonics, nanoelectronics, and nanomedicine. We show that DNA origami nanostructures can guide the assembly of achiral, spherical, metallic nanoparticles into nature-mimicking chiral geometries through hybridization between complementary DNA

  20. Electrochemical characterization of organosilane-functionalized nanostructured ITO surfaces

    NASA Astrophysics Data System (ADS)

    Pruna, R.; Palacio, F.; López, M.; Pérez, J.; Mir, M.; Blázquez, O.; Hernández, S.; Garrido, B.

    2016-08-01

    The electroactivity of nanostructured indium tin oxide (ITO) has been investigated for its further use in applications such as sensing biological compounds by the analysis of redox active molecules. ITO films were fabricated by using electron beam evaporation at different substrate temperatures and subsequently annealed for promoting their crystallization. The morphology of the deposited material was monitored by scanning electron microscopy, confirming the deposition of either thin films or nanowires, depending on the substrate temperature. Electrochemical surface characterization revealed a 45 % increase in the electroactive surface area of nanostructured ITO with respect to thin films, one third lower than the geometrical surface area variation determined by atomic force microscopy. ITO surfaces were functionalized with a model organic molecule known as 6-(ferrocenyl)hexanethiol. The chemical attachment was done by means of a glycidoxy compound containing a reactive epoxy group, the so-called 3-glycidoxypropyltrimethoxy-silane. ITO functionalization was useful for determining the benefits of nanostructuration on the surface coverage of active molecules. Compared to ITO thin films, an increase in the total peak height of 140 % was observed for as-deposited nanostructured electrodes, whereas the same measurement for annealed electrodes resulted in an increase of more than 400 %. These preliminary results demonstrate the ability of nanostructured ITO to increase the surface-to-volume ratio, conductivity and surface area functionalization, features that highly benefit the performance of biosensors.

  1. 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.

  2. 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.

  3. Synthesis and Functions of Ag2S Nanostructures

    NASA Astrophysics Data System (ADS)

    Cui, Chunyan; Li, Xiaoru; Liu, Jixian; Hou, Yongchao; Zhao, Yuqing; Zhong, Guocheng

    2015-11-01

    The paper presents a review about synthesis and applications of Ag2S nanostructures. As the modern photoelectric and biological materials, Ag2S nanomaterials are potentially useful for both structure and function purposes. Ag2S is a direction narrow band gap semiconductor with special properties. Ag2S nanostructures have been widely researched in chemistry and biochemistry fields because of their unusual optical, electrical, and mechanical properties. It can also be used in many fields, such as photovoltaic cells and infrared detector. In the past few years, Ag2S nanostructures have been synthesized by various methods. The article mainly discusses the four types of preparation methods. Moreover, this article shows a detailed review on the new properties, fabrication, and applications of Ag2S nanocrystals.

  4. Synthesis and Functions of Ag2S Nanostructures.

    PubMed

    Cui, Chunyan; Li, Xiaoru; Liu, Jixian; Hou, Yongchao; Zhao, Yuqing; Zhong, Guocheng

    2015-12-01

    The paper presents a review about synthesis and applications of Ag2S nanostructures. As the modern photoelectric and biological materials, Ag2S nanomaterials are potentially useful for both structure and function purposes. Ag2S is a direction narrow band gap semiconductor with special properties. Ag2S nanostructures have been widely researched in chemistry and biochemistry fields because of their unusual optical, electrical, and mechanical properties. It can also be used in many fields, such as photovoltaic cells and infrared detector. In the past few years, Ag2S nanostructures have been synthesized by various methods. The article mainly discusses the four types of preparation methods. Moreover, this article shows a detailed review on the new properties, fabrication, and applications of Ag2S nanocrystals. PMID:26525702

  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. Combination of lightweight elements and nanostructured materials for batteries.

    PubMed

    Chen, Jun; Cheng, Fangyi

    2009-06-16

    ), Co(3)O(4), TiS(2), and Ni(OH)(2) in battery applications. Electrochemical investigations reveal that we generally attain larger capacities and improved kinetics for electrode materials as their average particle size decreases. Novel nanostructures such as nanowires, nanotubes, nanourchins, and porous nanospheres show lower activation energy, enhanced reactivity, improved high-rate charge/discharge capability, and more controlled structural flexibility than their bulk counterparts. In particular, anode materials such as Si nanospheres and Fe(2)O(3) nanotubes can deliver reversible capacity exceeding 500 mA.h/g. (Graphite used commercially has a theoretical capacity of 372 mA x h/g.) Nanocomposite cathode materials such as NiP-doped LiFePO(4) and metal hydroxide-coated Ni(OH)(2) nanotubes allow us to integrate functional components, which enhance electrical conductivity and suppress volume expansion. Therefore, shifting from bulk to nanostructured electrode materials could offer a revolutionary opportunity to develop advanced green batteries with large capacity, high energy and power density, and long cycle life.

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

    PubMed

    Chen, Jun; Cheng, Fangyi

    2009-06-16

    ), Co(3)O(4), TiS(2), and Ni(OH)(2) in battery applications. Electrochemical investigations reveal that we generally attain larger capacities and improved kinetics for electrode materials as their average particle size decreases. Novel nanostructures such as nanowires, nanotubes, nanourchins, and porous nanospheres show lower activation energy, enhanced reactivity, improved high-rate charge/discharge capability, and more controlled structural flexibility than their bulk counterparts. In particular, anode materials such as Si nanospheres and Fe(2)O(3) nanotubes can deliver reversible capacity exceeding 500 mA.h/g. (Graphite used commercially has a theoretical capacity of 372 mA x h/g.) Nanocomposite cathode materials such as NiP-doped LiFePO(4) and metal hydroxide-coated Ni(OH)(2) nanotubes allow us to integrate functional components, which enhance electrical conductivity and suppress volume expansion. Therefore, shifting from bulk to nanostructured electrode materials could offer a revolutionary opportunity to develop advanced green batteries with large capacity, high energy and power density, and long cycle life. PMID:19354236

  9. Fabrication and characterization of carbon and boron carbide nanostructured materials

    NASA Astrophysics Data System (ADS)

    Reynaud, Sara

    Carbon is present in nature in a variety of allotropes and chemical compounds. Due to reduced dimensionality, nanostructured carbon materials, i.e. single walled carbon nanotubes (SWNTs), are characterized by unique physical and chemical properties. There is a potential for SWNTs use as biological probes and assists for tunable tissue growth in biomedical applications. However, the presumed cytotoxicity of SWNTs requires investigation of the risks of their incorporation into living systems. Boron is not found in nature in elementary form. Boron based materials are chemically complex and exist in various polymorphic forms, i.e. boron carbide (BC). Because BC is a lightweight material with exceptional mechanical and elastic properties, it is the ideal candidate for armor and ballistic applications. However, practical use of BC as armor material is limited because of its anomalous glass-like behaviour at high velocity impacts, which has been linked to stress-induced structural instability in one of BC polymorphs, B12(CCC). Theoretical calculations suggest that formation of B12(CCC) in BC could be suppressed by silicon doping. In the first part of this thesis, biocompatibility of SWNTs is investigated. It is shown that under normal cell implantation conditions, the electrical conductivity of the SWNTs decreases due to an increase in structural disorder. This research suggests that SWNTs can be functionalized by protein and biological cells reducing the risk of cytotoxicity. In the second part of this thesis, boron carbide nanostructured materials are synthesized and investigated. Radio frequency sputtering deposition technique is employed for fabrication of BC (Si free) and BC:Si thin films. Variation of plasma conditions and temperature are found to affect chemical composition, adhesion to the substrate and morphology of the films. It is shown that BC films are predominantly amorphous and a small addition of Si largely improves their mechanical properties. In addition

  10. 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.

  11. Inorganic nanostructured materials for high performance electrochemical supercapacitors.

    PubMed

    Liu, Sheng; Sun, Shouheng; You, Xiao-Zeng

    2014-02-21

    Electrochemical supercapacitors (ES) are a well-known energy storage system that has high power density, long life-cycle and fast charge-discharge kinetics. Nanostructured materials are a new generation of electrode materials with large surface area and short transport/diffusion path for ions and electrons to achieve high specific capacitance in ES. This mini review highlights recent developments of inorganic nanostructure materials, including carbon nanomaterials, metal oxide nanoparticles, and metal oxide nanowires/nanotubes, for high performance ES applications.

  12. 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

  13. Nanostructured materials for rechargeable batteries: synthesis, fundamental understanding and limitations

    SciTech Connect

    Zhan, Hui; Xiao, Jie; Nie, Zimin; Li, Xiaolin; Wang, Chong M.; Zhang, Jiguang; Liu, Jun

    2013-05-30

    Nanostructured materials have emerged as very attrcative electrode materials for energy storage due to their small sizes and structure/morphology related properties. The purpose of this article to discuss the opportunities and challenges of nanostructured materials for advanced energy storage devices. Nanostructured silicon (Si) anodes together with other cathode and anode materials are used as examples to illustrate the different methods available for synthesis and the range of materials that can be produced to improve the storage capacity and stability. Recent progresses in using well-defined nanostructures to gain new fundamental understanding of the complex electrochemical reactions and charge-discharge processes are also discussed. Finally, the paper addresses some key problems that are yet to be solved and the need to optimize the microstructures and control the high level architectures beyond nanoscale.

  14. Mechanically interlocked DNA nanostructures for functional devices.

    PubMed

    Jester, Stefan-S; Famulok, Michael

    2014-06-17

    CONSPECTUS: Self-assembled functional DNA oligonucleotide based architectures represent highly promising candidates for the creation of nanoscale devices. The field of DNA nanotechnology has emerged to a high level of maturity and currently constitutes one of the most dynamic, creative, and exciting modern research areas. The transformation from structural DNA nanotechnology to functional DNA architectures is already taking place with tremendous pace. Particularly the advent of DNA origami technology has propelled DNA nanotechnology forward. DNA origami provided a versatile method for precisely aligning structural and functional DNA modules in two and three dimensions, thereby serving as a means for constructing scaffolds and chassis required for the precise orchestration of multiple functional DNA architectures. Key modules of these will contain interlocked nanomechanical components made of DNA. The mechanical interlocking allows for performing highly specific and controlled motion, by reducing the dimensionality of diffusion-controlled processes without restrictions in motional flexibility. Examples for nanoscale interlocked DNA architectures illustrate how elementary functional units of future nanomachines can be designed and realized, and show what role interlocked DNA architectures may play in this endeavor. Functional supramolecular systems, in general, and nanomachinery, in particular, self-organize into architectures that reflect different levels of complexity with respect to their function, their arrangement in the second and third dimension, their suitability for different purposes, and their functional interplay. Toward this goal, DNA nanotechnology and especially the DNA origami technology provide opportunities for nanomechanics, nanorobotics, and nanomachines. In this Account, we address approaches that apply to the construction of interlocked DNA nanostructures, drawing largely form our own contributions to interlocked architectures based on double

  15. Biomolecular templating of functional hybrid nanostructures using repeat protein scaffolds.

    PubMed

    Romera, David; Couleaud, Pierre; Mejias, Sara H; Aires, Antonio; Cortajarena, Aitziber L

    2015-10-01

    The precise synthesis of materials and devices with tailored complex structures and properties is a requisite for the development of the next generation of products based on nanotechnology. Nowadays, the technology for the generation of this type of devices lacks the precision to determine their properties and is accomplished mostly by 'trial and error' experimental approaches. The use of bottom-up approaches that rely on highly specific biomolecular interactions of small and simple components is an attractive approach for the templating of nanoscale elements. In nature, protein assemblies define complex structures and functions. Engineering novel bio-inspired assemblies by exploiting the same rules and interactions that encode the natural diversity is an emerging field that opens the door to create nanostructures with numerous potential applications in synthetic biology and nanotechnology. Self-assembly of biological molecules into defined functional structures has a tremendous potential in nano-patterning and the design of novel materials and functional devices. Molecular self-assembly is a process by which complex 3D structures with specified functions are constructed from simple molecular building blocks. Here we discuss the basis of biomolecular templating, the great potential of repeat proteins as building blocks for biomolecular templating and nano-patterning. In particular, we focus on the designed consensus tetratricopeptide repeats (CTPRs), the control on the assembly of these proteins into higher order structures and their potential as building blocks in order to generate functional nanostructures and materials.

  16. 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.

  17. Multifunctional Upconversion-Magnetic Hybrid Nanostructured Materials: Synthesis and Bioapplications

    PubMed Central

    Li, Xiaomin; Zhao, Dongyuan; Zhang, Fan

    2013-01-01

    The combination of nanotechnology and biology has developed into an emerging research area: nano-biotechnology. Upconversion nanoparticles (UCNPs) have attracted a great deal of attention in bioapplications due to their high chemical stability, low toxicity, and high signal-to-noise ratio. Magnetic nanoparticles (MNPs) are also well-established nanomaterials that offer controlled size, ability to be manipulated externally, and enhancement of contrast in magnetic resonance imaging (MRI). As a result, these nanoparticles could have many applications in biology and medicine, including protein purification, drug delivery, and medical imaging. Because of the potential benefits of multimodal functionality in biomedical applications, researchers would like to design and fabricate multifunctional upconversion-magnetic hybrid nanostructured materials. The hybrid nanostructures, which combine UCNPs with MNPs, exhibit upconversion fluorescence alongside superparamagnetism property. Such structures could provide a platform for enhanced bioimaging and controlled drug delivery. We expect that the combination of unique structural characteristics and integrated functions of multifunctional upconversion-magnetic nanoparticles will attract increasing research interest and could lead to new opportunities in nano-bioapplications. PMID:23650477

  18. 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.

  19. Rapid Microwave Synthesis of Perovskite Oxide Nanostructures with Enhanced Functionality

    NASA Astrophysics Data System (ADS)

    Salazar, Gregory; Datta, Anuja; Mukherjee, Pritish

    2015-03-01

    Perovskite oxides are an important class of materials having high dielectric and piezoelectric coefficients, switchable ferroelectric (FE) polarization and interesting optical and electrical properties. Realization of functional devices based on classic perovskite oxides such as Pb(Zr0.52Ti0.48) O3 (PZT), and emerging Pb-free noncentrosymmetric (NCS) oxides, such as, ZnSnO3, ZnTiO3 and CaTiO3 have reinforced the investigation of these materials in multiple dimensions and length scales. However, large-scale synthesis and integration of ordered low-dimensional structures is a challenge, due to their complicated methodologies, high-cost and difficulties with phase stability. We discuss a generalized, cost-effective, rapid microwave synthesis route for size and shape selective nanostructure growth of these functional perovskite oxides on industrially viable flexible and hard substrates, stabilized by an enhanced ionic covalence. The rational synthesis approach allowed improved tunability of the size, shape, and orientation of the structures with improved electrical and FE properties. The facile fabrication route of these nanostructures may expand the outreach of probes for understanding the structure-property relationships in these hitherto unexplored and technologically important materials.

  20. 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.

  1. Nanostructured Materials in Different Dimensions for Sensing Applications

    NASA Astrophysics Data System (ADS)

    Morgen, Per; Drews, J.; Dhiman, Rajnish; Nielsen, Peter

    Future sensing elements should be more specific, more sensitive, more reversible, and faster than today's elements. These future sensing devices will either be integrated with suitable signal detection circuitry, typically based on Si microelectronics, or with optical signal detection, and finally interfaced to relevant state-of-the-art signal recognition hard- and software. Some of the more critical uses of sensors are in the dynamic surveillance of system parameters in complex machinery or in biological systems, such as our own bodies. Most of these demands are likely to be met by the continued rapid development of functional nanomaterials including bio-nanomaterials and biocompatible nanomaterials. A strong and increasing trend, also clear at this NATO-ASI, is the focus on using Au-dots deposited on various substrates for optical field enhancements and for other synergistic effects on electronic properties such as sheet conductivity, when deposited on polymer films or on metal oxide surfaces. Gas sensing with metal oxide surfaces is another very active area of development, where the high surface to volume ratio of thin films or nano-crystalline objects are in focus. In this report we demonstrate examples of the processing of silicon surfaces, aluminum surfaces and wooden saw dust powders to create nanostructured materials with interesting functional properties in novel types of self-limiting and self-organizing growths of one-, two- and three dimensional nano-template (i.e. nano-building block) systems, with a range of functionalities, as-formed, or after further integration. However, the focus in this report is on the growth processes and further treatments, as these are relatively new, and thus not widely known, but highly relevant for the functional properties of the resulting nanostructures, and for integration of the structures with silicon or in more complex systems.

  2. 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.

  3. Synthesis, characterization, and controlled assembly of functional nanostructures

    NASA Astrophysics Data System (ADS)

    Patete, Jonathan M.

    Nanomaterials represent a particularly interesting class of materials for research, as they bridge the gap between bulk materials and atomic or molecular structures, and often exhibit both novel chemical and physical properties. These properties may be altered not only by the chemical composition of the material but also by the size and shape of the nanoparticle. More specifically, the inherent anisotropy of one-dimensional nanostructures renders them as particularly efficient for electron transport applications. These materials are also highly sought after, because their distinctive shape allows for facile incorporation into functional device configurations. My graduate research has spanned several stages of nanotechnology from the synthesis and characterization of one-dimensional metal oxide nanostructures to the assembly of metal nanoparticles for practical device engineering. In particular, I have investigated the effect of the nanoscale size regime on the electronic, magnetic, and optical properties of as-prepared nanowires composed of hexagonal yttrium manganese oxide and olivine lithium iron phosphate. As a multiferroic material, h-YMnO3 is predominately sought after for applications in data storage devices. Alternatively, nanoscale LiFePO4 has shown a lot of promise as a cathode material in advanced lithium ion battery systems. The synthesis of both materials was achieved through template-directed methods, thereby allowing for precise control over the size and morphology of the as-obtained product. Finally, purposeful, directed methods for controlling the deposition pattern of metallic nanoparticles on a two-dimensional surface will be presented, and their viability as functional optical sensors will be explored.

  4. 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

  5. Covalently functionalized carbon nanostructures and methods for their separation

    DOEpatents

    Wang, YuHuang; Brozena, Alexandra H; Deng, Shunliu; Zhang, Yin

    2015-03-17

    The present invention is directed to carbon nanostructures, e.g., carbon nanotubes, methods of covalently functionalizing carbon nanostructures, and methods of separating and isolating covalently functionalized carbon. In some embodiments, carbon nanotubes are reacted with alkylating agents to provide water soluble covalently functionalized carbon nanotubes. In other embodiments, carbon nanotubes are reacted with a thermally-responsive agent and exposed to light in order to separate carbon nanotubes of a specific chirality from a mixture of carbon nanotubes.

  6. 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

  7. Bioinspired, functional nanoscale materials

    NASA Astrophysics Data System (ADS)

    Jun, In-Kook

    Functional nanomaterials in nature exhibit many unique functions and optical and mechanical properties. Examples of this include the dry adhesion of a gecko's foot, the reduced drag on a shark's skin, the high strength and toughness of nacre, and the superhydrophobic self-cleaning of a lotus leaf. This dissertation is devoted to creating unique and enhanced properties by mimicking such functional materials. We have developed a novel self-pumping membrane, which does not require an applied voltage. The self-pumping membrane harvests chemical energy from a surrounding fluid and uses it for accelerated mass transport across the membrane. A device such as this has promising applications in implantable or remotely operating autonomous devices and membrane-based purification systems. Reproducible and highly active surface enhanced Raman scattering (SERS) substrates were developed using a bottom-up self-assembly technology. With their high sensitivity and good reproducibility, the developed nanostructures (gold nanoparticle and nanohole arrays) as SERS substrates are very promising for applications such as ultra-sensitive detectors for chemicals and reproducible sensors for chemical and biological molecules. Binary colloidal crystals were created using a simple, fast, and scalable spin-coating technology. Although further investigation of the procedure is needed to improve the ordering of particles in the individual layers, the developed assembly technology has a promising outlook in applications such as optical integrated circuits and high-speed optical computing. Inorganic-organic nanocomposites were realized by assembling synthesized gibbsite nanoplatelets using the electrophoretic deposition and infiltration of a monomer followed by polymerization. Via surface modifications of gibbsite nanoplatelets, nanocomposites were further reinforced with covalent linkages between the inorganic platelets and organic matrix.

  8. 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

  9. 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.

  10. Phase separation and nanostructuring in the thermoelectric material PbTe[subscript 1−x]S[subscript x] studied using the atomic pair distribution function technique

    SciTech Connect

    Lin, He; Božin, E.S.; Billinge, S.J.L.; Androulakis, J.; Malliakas, C.D.; Lin, C.H.; Kanatzidis, M.G.

    2009-08-13

    The average and local structures of the (PbTe){sub 1-x}(PbS){sub x} system of thermoelectric materials has been studied using the Rietveld and atomic pair distribution function methods. Samples with 0.25 {le} x are macroscopically phase separated. Phase separation was suppressed in a quenched x=0.5 sample which, nonetheless, exhibited a partial spinodal decomposition. The promising thermoelectric material with x=0.16 showed intermediate behavior. Combining TEM and bulk scattering data suggests that the sample is a mixture of PbTe-rich material and a partially spinodally decomposed phase similar to the quenched 50% sample. This confirms that, in the bulk, this sample is inhomogeneous on a nanometer length scale, which may account for its enhanced thermoelectric figure of merit.

  11. [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.

  12. [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. PMID:25588475

  13. 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.

  14. Nanostructure of gel-derived aluminosilicate materials.

    PubMed

    Sinkó, Katalin; Hüsing, Nicola; Goerigk, Günter; Peterlik, Herwig

    2008-02-01

    In the present work, aluminosilicate aerogels prepared under various conditions were compared with respect to their nanostructures and porosity. The purpose of this investigation was to find a suitable way to predict the final product structure and to tailor a required texture. Several Al and Si precursors (Al nitrate, Al isopropoxide, Al acetate, tetraethoxysilane (TEOS), and sodium silicate) were used in our examinations; the solvent content (water and alcohols), surfactants, as well as the catalysts were varied. In addition, the aerogels were subjected to various heat treatments. Hybrid aerogels were synthesized by the addition of different polymers (poly(acrylic acid), polyvinyl acetate, and polydimethylsiloxane). Aluminosilicate and hybrid aerogel structures were investigated by 27Al MAS NMR, SAXS, SEM, and porosity measurements. Loose fractal structures with a good porosity and high Al incorporation can be achieved from TEOS and Al nitrate or isopropoxide via a sol-gel preparation route. The use of Al acetate led to compact aerogel structures independently of the Si precursor, the pH, and the catalyst.

  15. Functionalization of DNA Nanostructures for Cell Signaling Applications

    NASA Astrophysics Data System (ADS)

    Pedersen, Ronnie O.

    Transforming growth factor beta (TGF-beta) is an important cytokine responsible for a wide range of different cellular functions including extracellular matrix formation, angiogenesis and epithelial-mesenchymal transition. We have sought to use self-assembling DNA nanostructures to influence TGF-beta signaling. The predictable Watson Crick base pairing allows for designing self-assembling nanoscale structures using oligonucleotides. We have used the method of DNA origami to assemble structures functionalized with multiple peptides that bind TGF-beta receptors outside the ligand binding domain. This allows the nanostructures to cluster TGF-beta receptors and lower the energy barrier of ligand binding thus sensitizing the cells to TGF-beta stimulation. To prove efficacy of our nanostructures we have utilized immunofluorescent staining of Smad2/4 in order to monitor TGF-beta mediated translocation of Smad2/4 to the cell nucleus. We have also utilized Smad2/4 responsive luminescence constructs that allows us to quantify TGF-beta stimulation with and without nanostructures. To functionalize our nanostructures we relied on biotin-streptavidin linkages. This introduces a multivalency that is not necessarily desirable in all designs. Therefore we have investigated alternative means of functionalization. The first approach is based on targeting DNA nanostructure by using zinc finger binding proteins. Efficacy of zinc finger binding proteins was assayed by the use of enzyme-linked immunosorbent (ELISA) assay and atomic force microscopy (AFM). While ELISA indicated a relative specificity of zinc finger proteins for target DNA sequences AFM showed a high degree of non-specific binding and insufficient affinity. The second approach is based on using peptide nucleic acid (PNA) incorporated in the nanostructure through base pairing. PNA is a synthetic DNA analog consisting of a backbone of repeating N-(2-aminoethyl)-glycine units to which purine and pyrimidine bases are linked by

  16. Nanostructured magnesium has fewer detrimental effects on osteoblast function

    PubMed Central

    Weng, Lucy; Webster, Thomas J

    2013-01-01

    Efforts have been made recently to implement nanoscale surface features on magnesium, a biodegradable metal, to increase bone formation. Compared with normal magnesium, nanostructured magnesium has unique characteristics, including increased grain boundary properties, surface to volume ratio, surface roughness, and surface energy, which may influence the initial adsorption of proteins known to promote the function of osteoblasts (bone-forming cells). Previous studies have shown that one way to increase nanosurface roughness on magnesium is to soak the metal in NaOH. However, it has not been determined if degradation of magnesium is altered by creating nanoscale features on its surface to influence osteoblast density. The aim of the present in vitro study was to determine the influence of degradation of nanostructured magnesium, created by soaking in NaOH, on osteoblast density. Our results showed a less detrimental effect of magnesium degradation on osteoblast density when magnesium was treated with NaOH to create nanoscale surface features. The detrimental degradation products of magnesium are of significant concern when considering use of magnesium as an orthopedic implant material, and this study identified a surface treatment, ie, soaking in NaOH to create nanoscale features for magnesium that can improve its use in numerous orthopedic applications. PMID:23674891

  17. 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.

  18. Nanostructured material formulated acrylic bone cements with enhanced drug release.

    PubMed

    Shen, Shou-Cang; Ng, Wai Kiong; Dong, Yuan-Cai; Ng, Junwei; Tan, Reginald Beng Hee

    2016-01-01

    To improve antibiotic properties, poly(methyl methacrylate) (PMMA)-based bone cements are formulated with antibiotic and nanostructured materials, such as hydroxyapatite (HAP) nanorods, carbon nanotubes (CNT) and mesoporous silica nanoparticles (MSN) as drug carriers. For nonporous HAP nanorods, the release of gentamicin (GTMC) is not obviously improved when the content of HAP is below 10%; while the high content of HAP shows detrimental to mechanical properties although the release of GTMC can be substantially increased. As a comparison, low content of hollow nanostructured CNT and MSN can enhance drug delivery efficiency. The presence of 5.3% of CNT in formulation can facilitate the release of more than 75% of GTMC in 80 days, however, its mechanical strength is seriously impaired. Among nanostructured drug carriers, antibiotic/MSN formulation can effectively improve drug delivery and exhibit well preserved mechanical properties. The hollow nanostructured materials are believed to build up nano-networks for antibiotic to diffuse from the bone cement matrix to surface and achieve sustained drug release. Based on MSN drug carrier in formulated bone cement, a binary delivery system is also investigated to release GTMC together with other antibiotics.

  19. 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.

  20. Rapid prototyping of patterned functional nanostructures

    SciTech Connect

    FAN,HONGYOU; LU,YUNFENG; STUMP,AARON; REED,SCOTT T.; BAER,THOMAS A.; SCHUNK,P. RANDALL; PEREZ-LUNA,VICTOR; LOPEZ,GABRIEL P.; BRINKER,C. JEFFREY

    2000-02-09

    Living systems exhibit form and function on multiple length scales, and the prospect of imparting life-like qualities to man-made materials has inspired many recent efforts to devise hierarchical materials assembly strategies. For example, Yang et al. grew surfactant-templated mesoporous silica on hydrophobic patterns prepared by micro-contact printing {micro}CP{sup 3}. Trau et al. formed oriented mesoporous silica patterns, using a micro-molding in capillaries MIMIC technique, and Yang et al. combined MIMIC, polystyrene sphere templating, and surfactant-templating to create oxides with three levels of structural order. Overall, great progress has been made to date in controlling structure on scales ranging from several nanometers to several micrometers. However, materials prepared have been limited to oxides with no specific functionality, whereas for many of the envisioned applications of hierarchical materials in micro-systems, sensors, waveguides, photonics, and electronics, it is necessary to define both form and function on several length scales. In addition, the patterning strategies employed thus far require hours or even days for completion. Such slow processes are inherently difficult to implement in commercial environments. The authors have combined evaporation-induced (silica/surfactant) self-assembly EISA with rapid prototyping techniques like pen lithography, ink-jet printing, and dip-coating on micro-contact printed substrates to form hierarchically organized structures in seconds. In addition, by co-condensation of tetrafunctional silanes (Si(OR){sub 4}) with tri-functional organosilanes ((RO){sub 3}SiR{prime}){sup 12--14} or by inclusion of organic additives, the authors have selectively derivatized the silica framework with functional R{prime} ligands or molecules. The resulting materials exhibit form and function on multiple length scales: on the molecular scale, functional organic moieties are positioned on pore surfaces, on the mesoscale

  1. Nanostructuring with a crosslinkable discotic material.

    PubMed

    Kastler, Marcel; Pisula, Wojciech; Davies, Richard J; Gorelik, Tatiana; Kolb, Ute; Müllen, Klaus

    2007-08-01

    A high-yielding synthesis afforded a hexa-peri-hexabenzocoronene carrying acrylate units at the end of six attached alkyl spacers. The polymerization of these acrylate moieties could be initiated with thermal energy and through direct photoactivation without the addition of a photoinitiator. This allowed the organization of the liquid-crystalline material to be fixed in either the crystalline state or the mesophase, which preserved the organization in the respective phase. The use of a focused synchrotron beam permitted selected regions of a thin film to be rendered insoluble. After "developing" the film in this lithographic process by dissolving the soluble, unpolymerized material, defined nano-objects remained on the substrate. In addition, the pronounced aromatic pi stacking of the novel material allows an organization in mesoporous membranes that could be fixed by thermal crosslinking. After the removal of the inorganic template, mechanically stable nanotubes were obtained, which were characterized by different microscopy techniques.

  2. Molecular Motions in Functional Self-Assembled Nanostructures

    PubMed Central

    Dhotel, Alexandre; Chen, Ziguang; Delbreilh, Laurent; Youssef, Boulos; Saiter, Jean-Marc; Tan, Li

    2013-01-01

    The construction of “smart” materials able to perform specific functions at the molecular scale through the application of various stimuli is highly attractive but still challenging. The most recent applications indicate that the outstanding flexibility of self-assembled architectures can be employed as a powerful tool for the development of innovative molecular devices, functional surfaces and smart nanomaterials. Structural flexibility of these materials is known to be conferred by weak intermolecular forces involved in self-assembly strategies. However, some fundamental mechanisms responsible for conformational lability remain unexplored. Furthermore, the role played by stronger bonds, such as coordination, ionic and covalent bonding, is sometimes neglected while they can be employed readily to produce mechanically robust but also chemically reversible structures. In this review, recent applications of structural flexibility and molecular motions in self-assembled nanostructures are discussed. Special focus is given to advanced materials exhibiting significant performance changes after an external stimulus is applied, such as light exposure, pH variation, heat treatment or electromagnetic field. The crucial role played by strong intra- and weak intermolecular interactions on structural lability and responsiveness is highlighted. PMID:23348927

  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 Materials For Advanced Technological Applications: A Brief Introduction

    NASA Astrophysics Data System (ADS)

    Kulisch, W.; Freudenstein, R.; Ruiz, A.; Valsesia, A.; Sirghi, L.; Ponti, J.; Colpo, P.; Rossi, F.

    In this contribution a short introduction to nanostructured materials for advanced technological applications is presented. A major aim is to demonstrate, on the one hand, the diversity of approaches, methods, techniques and solutions, which are used currently worldwide — but also by the authors of the contributions collected in this book — in the field of nano-structured materials, but also that, on the other hand, these diverse topics are based on the same principles, face similar problems, and bear similar prospects for future applications. For this reason, frequent reference is made to the contributions to this book. Some examples to illustrate current topics, advances and problems are taken from the recent work of the present home institute of the author, the NanoBioTech group of the IHCP at the JRC.

  5. 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.

  6. Magnetic Cluster States in Nanostructured Materials

    SciTech Connect

    Diandra Leslie-Pelecky

    2008-06-13

    The goal of this work is to fabricate model nanomaterials with different types of disorder and use atomic-scale characterization and macroscopic magnetization measurements to understand better how specific types of disorder affects macroscopic magnetic behavior. This information can be used to produce magnetic nanomaterials with specific properties for applications such as permanent magnets, soft magnetic material for motors and biomedical applications.

  7. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    NASA Astrophysics Data System (ADS)

    Nan, Alexandrina; Bunge, Alexander; Turcu, Rodica

    2015-12-01

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  8. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    SciTech Connect

    Nan, Alexandrina Bunge, Alexander; Turcu, Rodica

    2015-12-23

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  9. Arc Plasma Synthesis of Nanostructured Materials: Techniques and Innovations

    SciTech Connect

    Das, A. K.; Bhoraskar, S. V.; Kakati, M.; Karmakar, Soumen

    2008-10-23

    Arc plasma aided synthesis of nanostructured materials has the potential of producing complex nano phase structures in bulk quantities. Successful implementation of this potential capability to industrial scale nano generation needs establishment of a plasma parameter control regime in terms of plasma gas, flow pattern, pressure, local temperature and the plasma fields to obtain the desired nano phase structures. However, there is a need to design innovative in situ experiments for generation of an extensive database and subsequently to correlate plasma parameters to the size, shape and phase of the generated nanostructures. The present paper reviews the various approaches utilized in the field of arc plasma nanosynthesis in general and in the authors' laboratories in particular. Simple plasma diagnostics and monitoring schemes have been used in conjunction with nano materials characterization tools to explore the possibility of controlling the size, shape, yield and phase composition of the arc generated nanostructures through plasma control. Case studies related to synthesis of AlN, Al2O3, TiO2, ZrO2, ZnO), magnetic (e.g. {gamma}-Fe2O3, Fe3O4) and single elemental materials (e.g. carbon nanotubes) are presented.

  10. Electron Field Emission from Nanostructured Carbon Materials

    NASA Astrophysics Data System (ADS)

    Gupta, Sanju

    2005-03-01

    Fabricating small structures has almost become fashionable and the rationale is that reducing one or more dimensions below some critical length changes the systems' physical properties drastically, where nanocrystalline diamond (n-D) and carbon nanotubes (CNTs) in the class of advanced carbon materials serve model examples. Emission of electrons at room temperature - cold electron emitters - are of vital importance for a variety of vacuum microelectronic devices - electron microscopes, photo multipliers, X-ray generators, lamps, and flat panel displays and microwave cathodes. Electron emitters may lead to otherwise difficult to obtain advantages in performance and/or design. This is the driving force to investigate the carbon-related materials as cold cathodes. In this talk, the performance of various forms of carbon in thin film form including diamond, n-D, and vertically aligned CNTs as cold cathodes for their potential use in field emission displays (FEDs) in terms of I-V characteristics and corresponding spatial imaging will be presented. Physics based models such as, NEA, surface modification, geometric enhancement, and microstructure alteration due to particle bombardment, and doping, will be described to support the experimental observations of electron field enhancement (low turn-on voltage, high current and emission site density) and its reliability from the abovementioned carbon-related materials. Other vacuum device applications such as thermionic power generators will be mentioned briefly.

  11. Heat transport by phonons in crystalline materials and nanostructures

    NASA Astrophysics Data System (ADS)

    Koh, Yee Kan

    This dissertation presents experimental studies of heat transport by phonons in crystalline materials and nanostructures, and across solid-solid interfaces. Particularly, this dissertation emphasizes advancing understanding of the mean-free-paths (i.e., the distance phonons propagate without being scattered) of acoustic phonons, which are the dominant heat carriers in most crystalline semiconductor nanostructures. Two primary tools for the studies presented in this dissertation are time-domain thermoreflectance (TDTR) for measurements of thermal conductivity of nanostructures and thermal conductance of interfaces; and frequency-domain thermoreflectance (FDTR), which I developed as a direct probe of the mean-free-paths of dominant heat-carrying phonons in crystalline solids. The foundation of FDTR is the dependence of the apparent thermal conductivity on the frequency of periodic heat sources. I find that the thermal conductivity of semiconductor alloys (InGaP, InGaAs, and SiGe) measured by TDTR depends on the modulation frequency, 0.1 ≤ f ≤ 10 MHz, used in TDTR measurements. Reduction in the thermal conductivity of the semiconductor alloys at high f compares well to the reduction in the thermal conductivity of epitaxial thin films, indicating that frequency dependence and thickness dependence of thermal conductivity are fundamentally equivalent. I developed the frequency dependence of thermal conductivity into a convenient probe of phonon mean-free-paths, a technique which I call frequency-domain thermoreflectance (FDTR). In FDTR, I monitor the changes in the intensity of the reflected probe beam as a function of the modulation frequency. To facilitate the analysis of FDTR measurements, I developed a nonlocal theory for heat conduction by phonons at high heating frequencies. Calculations of the nonlocal theory confirm my experimental findings that phonons with mean-free-paths longer than two times the penetration depth do not contribute to the apparent thermal

  12. Complex nanostructured materials from segmented copolymers prepared by ATRP.

    PubMed

    Kowalewski, T; McCullough, R D; Matyjaszewski, K

    2003-01-01

    The development of new controlled/living radical polymerization processes, such as Atom Transfer Radical Polymerization (ATRP) and other techniques such as nitroxide mediated polymerization and degenerative transfer processes, including RAFT, opened the way to the use of radical polymerization for the synthesis of well-defined, complex functional nanostructures. The development of such nanostructures is primarily dependent on self-assembly of well-defined segmented copolymers. This article describes the fundamentals of ATRP, relevant to the synthesis of such systems. The self-assembly of block copolymers prepared by ATRP is illustrated by three examples. In the first, block copolymers of poly(butyl acrylate) with polyacrylonitrile phase separate, leading to spherical, cylindrical or lamellar morphologies, depending on the block copolymer composition. At a higher temperature, polyacrylonitrile block converts to nanostructured carbon clusters, whereas poly(butyl acrylate) block serves as a sacrificial block, aiding the development of designed nanostructures. In the second example, conductive nanoribbons of poly(n-hexylthiophene) surrounded by a matrix of organic polymers are formed from block copolymers prepared by ATRP. The third example describes an inorganic-organic hybrid system consisting of hard nanocolloidal silica particles (approximately 20 nm) grafted by ATRP with well-defined polystyrene-poly(benzyl acrylate) block copolymer chains (approximately 1000 chains per particle). Silica cores in this system are surrounded by a rigid polystyrene inner shell and softer polyacrylate outer shell. PMID:15011074

  13. Functionalized Nanostructures with Application in Regenerative Medicine

    PubMed Central

    Perán, Macarena; García, María A.; López-Ruiz, Elena; Bustamante, Milán; Jiménez, Gema; Madeddu, Roberto; Marchal, Juan A.

    2012-01-01

    In the last decade, both regenerative medicine and nanotechnology have been broadly developed leading important advances in biomedical research as well as in clinical practice. The manipulation on the molecular level and the use of several functionalized nanoscaled materials has application in various fields of regenerative medicine including tissue engineering, cell therapy, diagnosis and drug and gene delivery. The themes covered in this review include nanoparticle systems for tracking transplanted stem cells, self-assembling peptides, nanoparticles for gene delivery into stem cells and biomimetic scaffolds useful for 2D and 3D tissue cell cultures, transplantation and clinical application. PMID:22489186

  14. 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.

  15. 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.

  16. Functional zinc oxide nanostructures for electronic and energy applications

    NASA Astrophysics Data System (ADS)

    Prasad, Abhishek

    ZnO has proven to be a multifunctional material with important nanotechnological applications. ZnO nanostructures can be grown in various forms such as nanowires, nanorods, nanobelts, nanocombs etc. In this work, ZnO nanostructures are grown in a double quartz tube configuration thermal Chemical Vapor Deposition (CVD) system. We focus on functionalized ZnO Nanostructures by controlling their structures and tuning their properties for various applications. The following topics have been investigated: (1) We have fabricated various ZnO nanostructures using a thermal CVD technique. The growth parameters were optimized and studied for different nanostructures. (2) We have studied the application of ZnO nanowires (ZnONWs) for field effect transistors (FETs). Unintentional n-type conductivity was observed in our FETs based on as-grown ZnO NWs. We have then shown for the first time that controlled incorporation of hydrogen into ZnO NWs can introduce p-type characters to the nanowires. We further found that the n-type behaviors remained, leading to the ambipolar behaviors of hydrogen incorporated ZnO NWs. Importantly, the detected p- and n- type behaviors are stable for longer than two years when devices were kept in ambient conditions. All these can be explained by an ab initio model of Zn vacancy-Hydrogen complexes, which can serve as the donor, acceptors, or green photoluminescence quencher, depend on the number of hydrogen atoms involved. (3) Next ZnONWs were tested for electron field emission. We focus on reducing the threshold field (Eth) of field emission from non-aligned ZnO NWs. As encouraged by our results on enhancing the conductivity of ZnO NWs by hydrogen annealing described in Chapter 3, we have studied the effect of hydrogen annealing for improving field emission behavior of our ZnO NWs. We found that optimally annealed ZnO NWs offered much lower threshold electric field and improved emission stability. We also studied field emission from ZnO NWs at moderate

  17. Synthesis and chemical modification of carbon nanostructures for materials applications

    NASA Astrophysics Data System (ADS)

    Higginbotham, Amanda Lynn

    This dissertation explores the structure, chemical reactivities, electromagnetic response, and materials properties of various carbon nanostructures, including single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), graphite, and graphene nanoribbons (GNRs). Efficient production and modification of these unique structures, each with their own distinct properties, will make them more accessible for applications in electronics, materials, and biology. A method is reported for controlling the permittivity from 1--1000 MHz of SWCNT-polymer composites (0.5 wt%) for radio frequency applications including passive RF antenna structures and EMI shielding. The magnitude of the real permittivity varied between 20 and 3.3, decreasing as higher fractions of functionalized-SWCNTs were added. The microwave absorbing properties and subsequent heating of carbon nanotubes were used to rapidly cure ceramic composites. With less than 1 wt% carbon nanotube additives and 30--40 W of directed microwave power (2.45 GHz), bulk composite samples reached temperatures above 500°C within 1 min. Graphite oxide (GO) polymer nanocomposites were developed at 1, 5, and 10 wt% for the purpose of evaluating the flammability reduction and materials properties of the resulting systems. Microscale oxygen consumption calorimetry revealed that addition of GO reduced the total heat release in all systems, and GO-polycarbonate composites demonstrated very fast self-extinguishing times in vertical open flame tests. A simple solution-based oxidative process using potassium permanganate in sulfuric acid was developed for producing nearly 100% yield of graphene nanoribbons (GNRs) by lengthwise cutting and unraveling of MWCNT sidewalls. Subsequent chemical reduction of the GNRs resulted in restoration of electrical conductivity. The GNR synthetic conditions were investigated in further depth, and an improved method which utilized a two-acid reaction medium was found to produce GNRs with

  18. Nanostructured Materials for Room-Temperature Gas Sensors.

    PubMed

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

    2016-02-01

    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.

  19. 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.

  20. Nanostructuring graphene for controlled and reproducible functionalization

    NASA Astrophysics Data System (ADS)

    Mali, Kunal S.; Greenwood, John; Adisoejoso, Jinne; Phillipson, Roald; de Feyter, Steven

    2015-01-01

    The `graphene rush' that started almost a decade ago is far from over. The dazzling properties of graphene have long warranted a number of applications in various domains of science and technology. Harnessing the exceptional properties of graphene for practical applications however has proved to be a massive task. Apart from the challenges associated with the large-scale production of the material, the intrinsic zero band gap, the inherently low reactivity and solubility of pristine graphene preclude its use in several high- as well as low-end applications. One of the potential solutions to these problems is the surface functionalization of graphene using organic building blocks. The `surface-only' nature of graphene allows the manipulation of its properties not only by covalent chemical modification but also via non-covalent interactions with organic molecules. Significant amount of research efforts have been directed towards the development of functionalization protocols for modifying the structural, electronic, and chemical properties of graphene. This feature article provides a glimpse of recent progress in the molecular functionalization of surface supported graphene using non-covalent as well as covalent chemistry.

  1. High-strength, thermally-stable nanostructured materials

    NASA Astrophysics Data System (ADS)

    Shankar, Ravi

    The properties of two technologically important precipitation-treatable alloys - Al 6061 and Inconel 718, that are deformed to large plastic strains at room temperature by machining, are presented. The strong effect of prior density of precipitates on the consequent microstructure refinement during chip formation was determined by deforming Al 6061 of different tempers to varying levels of strain, by varying the tool rake angle. Chips cut from peak-aged 6061, consisting of a fine dispersion of precipitates, produced the finest microstructure and are composed of sub-100 nm grains. On the other hand, coarser precipitate distributions in over-aged 6061 and an absence of precipitates in solution-treated 6061 resulted in much coarser microstructures. Thermal stability of such nanostructured chips with different levels of strain and precipitate distributions is analyzed by studying evolution of Vickers micro-hardness and microstructure after different heat treatments. Chips produced from the peak-aged temper and over-aged temper soften following heat treatment while those from the solution-treated state first, gain strength before softening. The results are rationalized based on prior studies of the characteristics and kinetics of precipitation and coarsening in Al-Mg-Si systems. It is then demonstrated that precipitate-stabilized nanostructured materials synthesized from a prototypical alloy system - Inconel 718, are extremely stable even after prolonged heat treatment for 240 hours at temperatures as high as one-half of the melting point. This extraordinary thermal stability is traced to the retention of a fine dispersion of precipitates in a nanostructured matrix even after extended heat treatment. It is anticipated that general design principles garnered from understanding of the causal phenomena determining strengthening and thermal stability, can lead to the development of alloy systems for the manufacture of high-strength, thermally-stable nanostructured materials.

  2. Thermal properties of graphene and nanostructured carbon materials

    NASA Astrophysics Data System (ADS)

    Balandin, Alexander A.

    2011-08-01

    Recent years have seen a rapid growth of interest by the scientific and engineering communities in the thermal properties of materials. Heat removal has become a crucial issue for continuing progress in the electronic industry, and thermal conduction in low-dimensional structures has revealed truly intriguing features. Carbon allotropes and their derivatives occupy a unique place in terms of their ability to conduct heat. The room-temperature thermal conductivity of carbon materials span an extraordinary large range -- of over five orders of magnitude -- from the lowest in amorphous carbons to the highest in graphene and carbon nanotubes. Here, I review the thermal properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder. Special attention is given to the unusual size dependence of heat conduction in two-dimensional crystals and, specifically, in graphene. I also describe the prospects of applications of graphene and carbon materials for thermal management of electronics.

  3. Nanostructured functional films from engineered repeat proteins

    PubMed Central

    Grove, Tijana Z.; Regan, Lynne; Cortajarena, Aitziber L.

    2013-01-01

    Fundamental advances in biotechnology, medicine, environment, electronics and energy require methods for precise control of spatial organization at the nanoscale. Assemblies that rely on highly specific biomolecular interactions are an attractive approach to form materials that display novel and useful properties. Here, we report on assembly of films from the designed, rod-shaped, superhelical, consensus tetratricopeptide repeat protein (CTPR). We have designed three peptide-binding sites into the 18 repeat CTPR to allow for further specific and non-covalent functionalization of films through binding of fluorescein labelled peptides. The fluorescence signal from the peptide ligand bound to the protein in the solid film is anisotropic, demonstrating that CTPR films can impose order on otherwise isotropic moieties. Circular dichroism measurements show that the individual protein molecules retain their secondary structure in the film, and X-ray scattering, birefringence and atomic force microscopy experiments confirm macroscopic alignment of CTPR molecules within the film. This work opens the door to the generation of innovative biomaterials with tailored structure and function. PMID:23594813

  4. Electrospinning of functional materials for biomedicine and tissue engineering

    NASA Astrophysics Data System (ADS)

    Inozemtseva, O. A.; Salkovskiy, Y. E.; Severyukhina, A. N.; Vidyasheva, I. V.; Petrova, N. V.; Metwally, H. A.; Stetciura, I. Y.; Gorin, D. A.

    2015-03-01

    Published data on nanostructured materials prepared by electrospinning are analyzed and generalized. Particular attention is devoted to the design and properties of nanocomposite fibrous materials and methods for modification and functionalization of fibre surface. The prospects for the application of non-woven materials for biotissue engineering and for the development of smart materials are considered. The bibliography includes 330 references.

  5. 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

  6. 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.

  7. Nanostructured materials: A novel approach to enhanced performance. Final report

    SciTech Connect

    Korth, G.E.; Froes, F.H.; Suryanarayana, C.

    1996-05-01

    Nanostuctured materials are an emerging class of materials that can exhibit physical and mechanical characteristics often exceeding those exhibited by conventional course grained materials. A number of different techniques can be employed to produce these materials. In this program, the synthesis methods were (a) mechanical alloying , (b) physical vapor deposition, and (c) plasma processing. The physical vapor deposition and plasma processing were discontinued after initial testing with subsequent efforts focused on mechanical alloying. The major emphasis of the program was on the synthesis, consolidation, and characterization of nanostructured Al-Fe, Ti-Al, Ti-Al-Nb, and Fe-Al by alloying intermetallics with a view to increase their ductilities. The major findings of this project are reported.

  8. 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

  9. Nanostructure multilayer materials for capacitor energy storage for EH vehicles

    SciTech Connect

    Barbee, T.W. Jr.; Johnson, C.W.

    1995-02-01

    Acceleration and regenerative breaking for electric and hybrid vehicles require high power capacitors to complement energy sources. Large, flat nanostructure multilayer capacitors (NMCS) can provide load balancing capacitance in EHVs of the future. Additional uses include snubber capacitors for power electronics such as motor drives, energy discharge capacitors for lasers, and numerous industrial and military electronics applications [1]. In the present work, we demonstrate the effectiveness of LLNL`s multilayer materials technology by fabricating NMC test films with high energy and power density.

  10. Surface functionalized nanostructured ceramic sorbents for the effective collection and recovery of uranium from seawater.

    PubMed

    Chouyyok, Wilaiwan; Pittman, Jonathan W; Warner, Marvin G; Nell, Kara M; Clubb, Donald C; Gill, Gary A; Addleman, R Shane

    2016-07-28

    The ability to collect uranium from seawater offers the potential for a nearly limitless fuel supply for nuclear energy. We evaluated the use of functionalized nanostructured sorbents for the collection and recovery of uranium from seawater. Extraction of trace minerals from seawater and brines is challenging due to the high ionic strength of seawater, low mineral concentrations, and fouling of surfaces over time. We demonstrate that rationally assembled sorbent materials that integrate high affinity surface chemistry and high surface area nanostructures into an application relevant micro/macro structure enables collection performance that far exceeds typical sorbent materials. High surface area nanostructured silica with surface chemistries composed of phosphonic acid, phosphonates, 3,4 hydroxypyridinone, and EDTA showed superior performance for uranium collection. A few phosphorous-based commercial resins, specifically Diphonix and Ln Resin, also performed well. We demonstrate an effective and environmentally benign method of stripping the uranium from the high affinity sorbents using inexpensive nontoxic carbonate solutions. The cyclic use of preferred sorbents and acidic reconditioning of materials was shown to improve performance. Composite thin films composed of the nanostructured sorbents and a porous polymer binder are shown to have excellent kinetics and good capacity while providing an effective processing configuration for trace mineral recovery from solutions. Initial work using the composite thin films shows significant improvements in processing capacity over the previously reported sorbent materials. PMID:27184739

  11. 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.

  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. 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.

  14. 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

  15. Engineering Living Functional Materials

    PubMed Central

    2016-01-01

    Natural materials, such as bone, integrate living cells composed of organic molecules together with inorganic components. This enables combinations of functionalities, such as mechanical strength and the ability to regenerate and remodel, which are not present in existing synthetic materials. Taking a cue from nature, we propose that engineered ‘living functional materials’ and ‘living materials synthesis platforms’ that incorporate both living systems and inorganic components could transform the performance and the manufacturing of materials. As a proof-of-concept, we recently demonstrated that synthetic gene circuits in Escherichia coli enabled biofilms to be both a functional material in its own right and a materials-synthesis platform. To demonstrate the former, we engineered E. coli biofilms into a chemical-inducer-responsive electrical switch. To demonstrate the latter, we engineered E. coli biofilms to dynamically organize biotic-abiotic materials across multiple length scales, template gold nanorods, gold nanowires, and metal/semiconductor heterostructures, and synthesize semiconductor nanoparticles (Chen, A. Y. et al. (2014) Synthesis and patterning of tunable multiscale materials with engineered cells. Nat. Mater.13, 515–523.). Thus, tools from synthetic biology, such as those for artificial gene regulation, can be used to engineer the spatiotemporal characteristics of living systems and to interface living systems with inorganic materials. Such hybrids can possess novel properties enabled by living cells while retaining desirable functionalities of inorganic systems. These systems, as living functional materials and as living materials foundries, would provide a radically different paradigm of materials performance and synthesis–materials possessing multifunctional, self-healing, adaptable, and evolvable properties that are created and organized in a distributed, bottom-up, autonomously assembled, and environmentally sustainable manner. PMID

  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. 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.

  18. 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.

  19. 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.

  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. Neutron-scattering characterization of nanostructured materials relevant to biotechnology

    NASA Astrophysics Data System (ADS)

    Loong, C.-K.; Thiyagarajan, P.; Kolesnikov, A. I.

    2004-10-01

    Biomedical nanotechnology is a rapidly emerging field that encompasses many disciplines including medicine, molecular biology, materials physics and chemistry, engineering, etc. The complexity of the targeted systems demands cross-disciplinary research and international collaboration. In the materials front, understanding the fundamental properties at molecular level is important to the realization of the full potential of substances and the fruition of eventual technological applications. Neutron-scattering characterization of biomolecular systems can in principle provide unique information pertinent to nanotechnological applications. But the method is not widely utilized because neutron facilities are not normally located at industrial laboratories and university campuses. We introduce the techniques of neutron scattering for studying the organization of nanoscale structural units and their dynamic response to physical-chemical conditions. Examples are given to illustrate neutron characterization of nanostructured biomaterials and the implications for biotechnology.

  2. Understanding and tuning nanostructured materials for chemical energy conversion

    NASA Astrophysics Data System (ADS)

    Jian, Guoqiang

    The conversion of energy that employs chemical reaction is termed chemical energy conversion. In my dissertation, I have focused on chemical energy conversion systems involving energetic materials and lithium ion batteries, where performance is strongly dependent on the properties of materials and their architecture. The objective of this study is to enhance our understanding and tuning of nanostructured materials that might find application toward energetic materials and electrode materials in lithium ion batteries. Rapid heating diagnostics tools, i.e. temperature-jump techniques, have been used to study the ignition of aluminum nanoparticles, nanothermite reaction mechanism and metal oxides nanoparticles decomposition under rapid heating conditions (˜105-106 K/s). Time-resolved mass spectra results support the hypothesis that Al containing species diffuse outwards through the oxide shell. Low effective activation energies were found for metal oxides nanoparticles decomposition at high heating rates, implying the mass transfer control at high heating rates. The role of oxygen release from oxidizer in nanothermite reactions have been examined for several different systems, including some using microsized oxidizer (i.e., nano-Al/micro-I 2O5). In particular, for periodate based nanothermites, direct evidence from high heating rate SEM and mass spectrometry results support that direct gas phase oxygen release from oxidizer decomposition is critical in its ignition and combustion. Efforts have also been made to synthesize nanostructured materials for nanoenergetic materials and lithium ion batteries applications. Hollow CuO spheres were synthesized by aerosol spray pyrolysis, employing a gas blowing mechanism for the formation of hollow structure during aerosol synthesis. The materials synthesized as oxidizers in nanothermite demonstrated superior performance, and of particular note, periodate salts based nanothermite demonstrated the best gas generating performance

  3. Functionalized carbon nanostructures for hydrogen catalysis

    NASA Astrophysics Data System (ADS)

    Hu, Lung-Hao

    Sodium borohydride, NaBH4, is widely used as a source of pure hydrogen. Hydrogen is of interest because it is a source of clean energy. It can be converted directly into electrical energy by means of fuel cells. One of the objectives of this thesis was to develop a new catalytic process to (i) enhance the rate of hydrogen generation, and (ii) to achieve hydrogen generation equal to 100% of the theoretically expected value. The catalyst investigated in this research is constructed by starting from single wall carbon nanotubes (SWNT). This material has a very high specific surface area and good conductivity. The SWNT were formed into a paper by a special filtration process. Polysilazane, a polymeric precursor (Ceraset(TM)-SN from KiON Corp., Wiesbaden, Germany) was diluted by acetone and then layered onto SWNT paper. The Ceraset coated SWNT was then pyrolyzed at 1100°C for three hours to form a silicon carbonitride (SiCN), polymer derived ceramic (PDC), layer on the surface of SWNT filtered paper. This functionalized SiCN carbon nanotube paper (SiCN/CNT) was used as the substrate for catalyst dispersions. The catalyst consisted of transition metals, Pt/Pd/Ru. Suspension solutions of Pt, Pd and Ru were impregnated onto the SiCN/CNT paper with the expectation of creating a monolayer of these transition metals on surface of the SiCN/CNT substrate. It is likely that an interaction could occur between the transition metals and the silicon atoms present in the SiCN layer on the surface of the carbon nanotubes. It is known that transition metals and silicon react to form silicides, suggesting the formation of a strong Si-transition metal bond. Therefore, it is possible that this bond could provide good wetting of metal atoms on SiCN functionalized carbon nanotube substrate. In the limit a monolayer of the transition metals may be achieved, which would correspond to a near zero dihedral angle between the substrate and the cluster of transition metals. In such a scenario a

  4. Characterization of self-assembled functional polymeric nanostructures: I. magnetic nanostructures from metallopolymers II. Zwitterionic polymer vesicles in ionic liquid

    NASA Astrophysics Data System (ADS)

    Maddikeri, Raghavendra Raj

    Two diverse projects illustrate the application of various materials characterization techniques to investigate the structure and properties of nanostructured functional materials formed in both bulk as well as in solutions. In the first project, ordered magnetic nanostructures were formed within polymer matrix by novel metallopolymers. The novel metal-functionalized block copolymers (BCPs) enabled the confinement of cobalt metal ions within nanostructured BCP domains, which upon simple heat treatment resulted in room temperature ferromagnetic (RTFM) materials. On the contrary, cobalt functionalized homopolymer having similar chemical structure and higher loading of metal-ion are unstructured and exhibited superparamagnetic (SPM) behavior at room temperature. Based on a series of detailed investigations, using various materials characterization techniques, it was hypothesized that the SPM cobalt particles within BCP microdomains exhibited a collective behavior due to increased dipolar interactions between them under the nanoconfinement of cylindrical domains in BCP, resulting in RTFM behavior. On contrary, the same SPM cobalt particles formed within homopolymer, without any confinement exhibited SPM behavior either due to lack of interactions or random interactions between them. To further support this hypothesis, a series of BCPs were prepared in which the BCP morphology was varied between the cylindrical, lamellar, and inverted cylindrical phases and their magnetic properties were compared. All these BCPs, which are nanostructured, exhibited RTFM behavior, further supporting the proposed hypothesis. Different dimensionality or degree of nanoconfinement in BCP morphologies affected the magnetization reversal processes in these BCPs, yielding different macroscopic magnetic properties. Most strongly constrained cylindrical morphology has shown best magnetic properties (highest coercivity) among other BCP morphologies. Inverted cylindrical morphology, in which a 3-D

  5. Ultrafast laser functionalized rare phased gold-silicon/silicon oxide nanostructured hybrid biomaterials.

    PubMed

    Premnath, P; Tan, B; Venkatakrishnan, K

    2015-12-01

    We introduce a hybrid nanostructured biomaterial that is a combination of rare phases of immiscible gold and silicon oxide, functionalized via ultrafast laser synthesis. For the first time, we show cancer controlling properties of rare phases of gold silicides, which include Au7Si, Au5Si, Au0.7Si2.3 and Au8Si2. Conventionally, pure forms of gold and silicon/silicon oxide are extensively employed in targeted therapy and drug delivery systems due to their unique properties. While silicon and silicon oxide nanoparticles have shown biocompatibility, gold nanoparticles show conflicting results based on their size and material properties. Several studies have shown that gold and silicon combinations produce cell controlling properties, however, these studies were not able to produce a homogenous combination of gold and silicon, owing to its immiscibility. A homogenous combination of gold and silicon may potentially enable properties that have not previously been reported. We describe rare phased gold-silicon oxide nanostructured hybrid biomaterials and its unique cancer controlling properties, owing to material properties, concentration, size and density. The gold-silicon oxide nanostructured hybrid is composed of individual gold-silicon oxide nanoparticles in various concentrations of gold and silicon, some nanoparticles possess a gold-core and silicon-shell like structure. The individual nanoparticles are bonded together forming a three dimensional nanostructured hybrid. The interaction of the nanostructured hybrids with cervical cancer cells showed a 96% reduction in 24h. This engineered nanostructured hybrid biomaterial presents significant potential due to the combination of immiscible gold and silicon oxide in varying phases and can potentially satiate the current vacuum in cancer therapy.

  6. Ultrafast laser functionalized rare phased gold-silicon/silicon oxide nanostructured hybrid biomaterials.

    PubMed

    Premnath, P; Tan, B; Venkatakrishnan, K

    2015-12-01

    We introduce a hybrid nanostructured biomaterial that is a combination of rare phases of immiscible gold and silicon oxide, functionalized via ultrafast laser synthesis. For the first time, we show cancer controlling properties of rare phases of gold silicides, which include Au7Si, Au5Si, Au0.7Si2.3 and Au8Si2. Conventionally, pure forms of gold and silicon/silicon oxide are extensively employed in targeted therapy and drug delivery systems due to their unique properties. While silicon and silicon oxide nanoparticles have shown biocompatibility, gold nanoparticles show conflicting results based on their size and material properties. Several studies have shown that gold and silicon combinations produce cell controlling properties, however, these studies were not able to produce a homogenous combination of gold and silicon, owing to its immiscibility. A homogenous combination of gold and silicon may potentially enable properties that have not previously been reported. We describe rare phased gold-silicon oxide nanostructured hybrid biomaterials and its unique cancer controlling properties, owing to material properties, concentration, size and density. The gold-silicon oxide nanostructured hybrid is composed of individual gold-silicon oxide nanoparticles in various concentrations of gold and silicon, some nanoparticles possess a gold-core and silicon-shell like structure. The individual nanoparticles are bonded together forming a three dimensional nanostructured hybrid. The interaction of the nanostructured hybrids with cervical cancer cells showed a 96% reduction in 24h. This engineered nanostructured hybrid biomaterial presents significant potential due to the combination of immiscible gold and silicon oxide in varying phases and can potentially satiate the current vacuum in cancer therapy. PMID:26539809

  7. 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

  8. Functionalized surfaces and nanostructures for nanotechnological applications

    NASA Astrophysics Data System (ADS)

    2003-01-01

    CMOS roadmap in sight at around 10 nm, combined with the uncertainly principal's limit of Von Neuman electronics at 2 nm, that merely making things smaller will not help us. Replacing CMOS transistors on a one for one basis with some type of nano device would have the effect of drastically increasing fabrication costs, while offering only a marginal improvement over current technologies. However, nanotechnology offers us a way out of this technological and financial cul-de-sac by building devices from the bottom up. Techniques such as self assembly, perhaps assisted by templates created by nano imprint lithography, a notable European success, combined with our understanding of the workings of polymers and molecules such as Rotoxane at the nanoscale open up a whole new host of possibilities. Whether it is avoiding Moore's second law by switching to plastic electronics, or using molecular electronics, our understanding of the behaviour of materials on the scale of small molecules allows a variety of alternative approaches, to produce smarter, cheaper devices. The new understandings will also allow us to design new architectures, with the end result that functionality will become a more valid measure of performance than transistor density or operations per second. 8. Nanotechnology is new It often comes as a surprise to learn that the Romans and Chinese were using nanoparticles thousands of years ago. Similarly, every time you light a match, fullerenes are produced. Degusssa have been producing carbon black, the substance that makes car tyres black and improves the wear resistance of the rubber, since the 1920s. Of course they were not aware that they were using nanotechnology, and as they had no control over particle size, or even any knowledge of the nanoscale they were not using nanotechnology as currently defined. What is new about nanotechnology is our ability to not only see, and manipulate matter on the nanoscale, but our understanding of atomic scale interactions

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Repeat protein engineering: creating functional nanostructures/biomaterials from modular building blocks.

    PubMed

    Main, Ewan R G; Phillips, Jonathan J; Millership, Charlotte

    2013-10-01

    There is enormous interest in molecular self-assembly and the development of biological systems to form smart nanostructures for biotechnology (so-called 'bottom-up fabrications'). Repeat proteins are ideal choices for development of such systems as they: (i) possess a relatively simple relationship between sequence, structure and function; (ii) are modular and non-globular in structure; (iii) act as diverse scaffolds for the mediation of a diverse range of protein-protein interactions; and (iv) have been extensively studied and successfully engineered and designed. In the present review, we summarize recent advances in the use of engineered repeat proteins in the self-assembly of novel materials, nanostructures and biosensors. In particular, we show that repeat proteins are excellent monomeric programmable building blocks that can be triggered to associate into a range of morphologies and can readily be engineered as stimuli-responsive biofunctional materials.

  15. Semiconductor nanocrystals functionalized with antimony telluride zintl ions for nanostructured thermoelectrics.

    PubMed

    Kovalenko, Maksym V; Spokoyny, Boris; Lee, Jong-Soo; Scheele, Marcus; Weber, Andrew; Perera, Susanthri; Landry, Daniel; Talapin, Dmitri V

    2010-05-19

    The energy efficiency of heat engines could be improved by the partial recovery of waste heat using thermoelectric (TE) generators. We show the possibility of designing nanostructured TE materials using colloidal inorganic nanocrystals functionalized with molecular antimony telluride complexes belonging to the family of Zintl ions. The unique advantage of using Zintl ions as the nanocrystal surface ligands is the possibility to convert them into crystalline metal chalcogenides, thus linking individual nanobuilding blocks into a macroscopic assembly of electronically coupled functional modules. This approach allows preserving the benefits of nanostructuring and quantum confinement while enabling facile charge transport through the interparticle boundaries. A developed methodology was applied for solution-based fabrication of nanostructured n- and p-type Bi(2-x)Sb(x)Te(3) alloys with tunable composition and PbTe-Sb(2)Te(3) nanocomposites with controlled grain size. Characterization of the TE properties of these materials showed that their Seebeck coefficients, electrical and thermal conductivities, and ZT values compared favorably with those of previously reported solution-processed TE materials.

  16. 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

  17. 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.

  18. Resonant dielectric nanostructures: a low-loss platform for functional nanophotonics

    NASA Astrophysics Data System (ADS)

    Decker, Manuel; Staude, Isabelle

    2016-10-01

    This review overviews the state of the art of research into high-index dielectric nanoresonators and their use in functional photonic nanostructures at optical frequencies. We start by providing the motivations for this research area and by putting it into context with the more well-established subfields of nanophotonics, in particular nanoplasmonics. Following the introduction, fundamental concepts regarding the optical properties of subwavelength dielectric nanoresonators are established. To this end, we provide a brief summary of the Mie theory, before focussing on optically induced magnetic response in Mie-resonant dielectric nanoparticles. We discuss the influence of the nanoparticle’s shape on its optical response, and provide an overview of directional effects that can occur when light is scattered by a Mie-resonant nanoparticle. We then dedicate a few words to technology-related aspects, including an overview of fabrication methods for Mie-resonant dielectric nanoparticles. Next, recent progress on all-dielectric nanoantennas is presented, focussing on strategies to locally enhance optical near-fields and to achieve directional emission patterns. We then turn to all-dielectric metasurfaces and their potential applications. We touch on dielectric metamaterial reflectors and Fano-resonant dielectric metasurfaces, before discussing graded Mie-resonant dielectric metasurfaces for wavefront control applications in more detail. Following this, an overview of the recent progress in active, tunable and nonlinear dielectric nanostructures is provided. Finally, prospects and challenges are discussed, particularly the realization of highly efficient Mie-resonant nanostructures at visible frequencies, the integration of Mie-resonant nanostructures with active and functional materials, and the construction of three-dimensional high-index dielectric nanostructures.

  19. Boron-based nanostructures: Synthesis, functionalization, and characterization

    NASA Astrophysics Data System (ADS)

    Bedasso, Eyrusalam Kifyalew

    Boron-based nanostructures have not been explored in detail; however, these structures have the potential to revolutionize many fields including electronics and biomedicine. The research discussed in this dissertation focuses on synthesis, functionalization, and characterization of boron-based zero-dimensional nanostructures (core/shell and nanoparticles) and one-dimensional nanostructures (nanorods). The first project investigates the synthesis and functionalization of boron-based core/shell nanoparticles. Two boron-containing core/shell nanoparticles, namely boron/iron oxide and boron/silica, were synthesized. Initially, boron nanoparticles with a diameter between 10-100 nm were prepared by decomposition of nido-decaborane (B10H14) followed by formation of a core/shell structure. The core/shell structures were prepared using the appropriate precursor, iron source and silica source, for the shell in the presence of boron nanoparticles. The formation of core/shell nanostructures was confirmed using high resolution TEM. Then, the core/shell nanoparticles underwent a surface modification. Boron/iron oxide core/shell nanoparticles were functionalized with oleic acid, citric acid, amine-terminated polyethylene glycol, folic acid, and dopamine, and boron/silica core/shell nanoparticles were modified with 3-(amino propyl) triethoxy silane, 3-(2-aminoethyleamino)propyltrimethoxysilane), citric acid, folic acid, amine-terminated polyethylene glycol, and O-(2-Carboxyethyl)polyethylene glycol. A UV-Vis and ATR-FTIR analysis established the success of surface modification. The cytotoxicity of water-soluble core/shell nanoparticles was studied in triple negative breast cancer cell line MDA-MB-231 and the result showed the compounds are not toxic. The second project highlights optimization of reaction conditions for the synthesis of boron nanorods. This synthesis, done via reduction of boron oxide with molten lithium, was studied to produce boron nanorods without any

  20. The equipment for controlling the structure and functional properties of nanostructured composite films

    NASA Astrophysics Data System (ADS)

    Burov, V. G.; Plotnikova, N. V.; Prokhorenko, E. V.; Smirnov, A. I.

    2016-04-01

    The article is devoted to the creation of an instrumental system allowing evaluating the functional properties and current-voltage characteristics of nanostructured composite films at different temperatures and other environmental parameters. The system is based on an assessment of current-voltage characteristics of a nanostructured film material. The main components of the system are a chamber and a unit for current-voltage characteristics measuring. The stage with the test material and the contact system are provided with a heating element and a cooling system thus allowing warming to 150 °C and fast cooling to negative temperatures by liquid nitrogen circulating. The chamber body leak proofness against the external environment allows forming a composition of the atmosphere at a predetermined humidity level, which is essential for the measurement of current-voltage characteristics of polymer materials. The article describes the design features of the instrumental system and results of its application used for determining the properties of polymer nanostructured composite films.

  1. Neutron and X-ray Characterization of Nanostructured Polymeric Materials

    NASA Astrophysics Data System (ADS)

    Russell, Thomas

    2008-03-01

    Controlling the orientation and lateral ordering of the block copolymer microdomains is key to their use as templates and scaffolds for the fabrication of nanostructured materials. Processes must be robust, rapid and simple to implement and should not introduce disruptive processing steps that would impede their use. Grazing incidence small angle x-ray scattering (GISAXS) and neutron neutron scattering have proven to be critical for the characterization of the static and real time development of structure in thin films of block copolymers. Here, studies on poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) diblock copolymers prepared from mixed solvents will be discussed that show highly oriented, cylindrical microdomains with a high degree of lateral order on a wide range of substrates, including silicon oxide, polystyrene, germanium, polyimide, and poly(butylene terephthalate). The preferential solvation of the P4VP block with an alcohol was used to induce a reconstruction that left a nanoporous film upon drying. The evaporation of gold onto the reconstructed films produced thermally stable films that are resistant to reactive ion etching. GISAXS was used to quantitatively examine the structure of these composite films and the transfer of the patterns to the underlying substrate. (research done in collaboration with Soojin Park, Jia-Yu Wang, Bokyung Kim University of Massachusetts), Benjamin Ocko (Brookhaven National Laboratory) and Jin Wang (Argonne National Laboratory).

  2. 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

  3. 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

  4. Synthesis and applications of bioinspired inorganic nanostructured materials

    NASA Astrophysics Data System (ADS)

    Bassett, David C.

    2011-12-01

    Although the study of biominerals may be traced back many centuries, it is only recently that biological principles have been applied to synthetic systems in processes termed "biomimetic" and "bioinspired" to yield materials syntheses that are otherwise not possible and may also reduce the expenditure of energy and/or eliminate toxic byproducts. Many investigators have taken inspiration from interesting and unusual minerals formed by organisms, in a process termed biomineralisation, to tailor the nanostructure of inorganic materials not necessarily found biogenically. However, the fields of nanoparticle synthesis and biomineralisation remain largely separate, and this thesis is an attempt to apply new studies on biomineralisation to nanomaterials science. Principally among the proteins that influence biomineralisation is a group comprised largely of negatively charged aspartic acid residues present in serum. This study is an investigation determining the ability of these serum proteins and other anolagous biomolecules to stabilise biologically relevant amorphous minerals and influence the formation of a variety of materials at the nanoscale. Three different materials were chosen to demonstrate this effect; gold was templated into nanosized single crystals by the action of bioorganic molecules, and the utility of these nanoparticles as a biosensor was explored. The influence of bioorganic molecules on the phase selection and crystal size restriction of titanium dioxide, an important semiconductor with many applications, was explored. The use of bioorganically derived nanoparticles of titanium dioxide was then demonstrated as a highly efficient photocatalyst. Finally, calcium carbonate, a prevalent biomineral was shown to form highly ordered structures over a variety of length scales and different crystalline polymorphs under the influence of a templating protein. In addition, an alternative route to producing calcium phosphate nanoparticle dispersions by mechanical

  5. Novel biomaterials: plasma-enabled nanostructures and functions

    NASA Astrophysics Data System (ADS)

    Levchenko, Igor; Keidar, Michael; Cvelbar, Uroš; Mariotti, Davide; Mai-Prochnow, Anne; Fang, Jinghua; (Ken Ostrikov, Kostya

    2016-07-01

    Material processing techniques utilizing low-temperature plasmas as the main process tool feature many unique capabilities for the fabrication of various nanostructured materials. As compared with the neutral-gas based techniques and methods, the plasma-based approaches offer higher levels of energy and flux controllability, often leading to higher quality of the fabricated nanomaterials and sometimes to the synthesis of the hierarchical materials with interesting properties. Among others, nanoscale biomaterials attract significant attention due to their special properties towards the biological materials (proteins, enzymes), living cells and tissues. This review briefly examines various approaches based on the use of low-temperature plasma environments to fabricate nanoscale biomaterials exhibiting high biological activity, biological inertness for drug delivery system, and other features of the biomaterials make them highly attractive. In particular, we briefly discuss the plasma-assisted fabrication of gold and silicon nanoparticles for bio-applications; carbon nanoparticles for bioimaging and cancer therapy; carbon nanotube-based platforms for enzyme production and bacteria growth control, and other applications of low-temperature plasmas in the production of biologically-active materials.

  6. 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

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

    PubMed

    Kiani, Amirkianoosh; Waraich, Palneet Singh; Venkatakrishnan, Krishnan; Tan, Bo

    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

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

    NASA Astrophysics Data System (ADS)

    Kiani, Amirkianoosh; Waraich, Palneet Singh; Venkatakrishnan, Krishnan; Tan, Bo

    2012-09-01

    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.

  9. Methods of electrophoretic deposition for functionally graded porous nanostructures and systems thereof

    SciTech Connect

    Worsley, Marcus A; Baumann, Theodore F; Satcher, Joe H; Olson, Tammy Y; Kuntz, Joshua D; Rose, Klint A

    2015-03-03

    In one embodiment, an aerogel includes a layer of shaped particles having a particle packing density gradient in a thickness direction of the layer, wherein the shaped particles are characterized by being formed in an electrophoretic deposition (EPD) process using an impurity. In another embodiment, a method for forming a functionally graded porous nanostructure includes adding particles of an impurity and a solution to an EPD chamber, applying a voltage difference across the two electrodes of the EPD chamber to create an electric field in the EPD chamber, and depositing the material onto surfaces of the particles of the impurity to form shaped particles of the material. Other functionally graded materials and methods are described according to more embodiments.

  10. Vertically Aligned Nanostructured Arrays of Inorganic Materials: Synthesis, Distinctive Physical Phenomena, and Device Integration

    NASA Astrophysics Data System (ADS)

    Velazquez, Jesus Manuel

    materials to obtain a fundamental understanding of the influence of finite size and surface restructuring on electronic instabilities in the proximity of the Fermi level. We present here a novel synthetic approach that takes advantage of the intrinsic octahedral symmetry of rock-salt-structured VO to facilitate the growth of six-armed nanocrystallites of related, technologically more important binary vanadium oxide V2O5 . The prepared nanostructures exhibit clear six-fold symmetry and most notably show remarkable retention of electronic structure. The latter has been evidenced through extensive X-ray absorption spectroscopy measurements. We have further designed a facile, generalizable, and entirely scalable approach for the fabrication of vertically aligned arrays of Fe2O 3/polypyrrole core---shell nanostructures and polypyrrole nanotubes. Our "all electrochemical" approach is based on the fabrication of α-Fe 2O3 nanowire arrays by the simple heat treatment of commodity low carbon steel substrates, followed by electropolymerization of conformal polypyrrole sheaths around the nanowires. Subsequently, electrochemical etching of the nanowires yields large-area vertically aligned polypyrrole nanotube arrays on the steel substrate. The developed methodology is generalizable to functionalized pyrrole monomers and represents a significant practical advance of relevance to the technological implementation of conjugated polymer nanostructures in electrochromics, electrochemical energy storage, and sensing. As another variation of this general synthetic route, we have extended the practice of our simple oxidative process for the fabrication of large-area ZnO nanostructures, specifically highly aligned nanowire arrays integrated onto galvanized steel substrates which via a simple device design and additive piezoelectric nanopower generation were measured across the array substrates. The nanomaterial syntheses and device fabrication approaches developed here will enable facile

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

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Han

    ultimate strains than nacre and pure GO paper (also synthesized by filtration). Specifically, it exhibits ˜30 times higher fracture energy than filtrated graphene paper and nacre, ˜100 times tougher than filtrated GO paper. Besides reinforced nanocomposites, we further explored the self-assembly of spherical colloids and the templating nanofabrication of moth-eye-inspired broadband antireflection coatings. Binary crystalline structures can be easily accomplished by spin-coating double-layer nonclose-packed colloidal crystals as templates, followed by colloidal templating. The polymer matrix between self-assembled colloidal crystal has been used as a sacrificial template to define the resulting periodic binary nanostructures, including intercalated arrays of silica spheres and polymer posts, gold nanohole arrays with binary sizes, and dimple-nipple antireflection coatings. The binary-structured antireflection coatings exhibit better antireflective properties than unitary coatings. Natural optical structures and nanocomposites teach us a great deal on how to create high performance artificial materials. The bottom-up technologies developed in this thesis are scalable and compatible with standard industrial processes, promising for manufacturing high-performance materials for the benefits of human beings.

  12. Shape-tailoring and catalytic function of anisotropic gold nanostructures

    PubMed Central

    2011-01-01

    We report a facile, one-pot, shape-selective synthesis of gold nanoparticles in high yield by the reaction of an aqueous potassium tetrachloroaurate(III) solution with a commercially available detergent. We prove that a commercial detergent can act as a reducing as well as stabilizing agent for the synthesis of differently shaped gold nanoparticles in an aqueous solution at an ambient condition. It is noteworthy that the gold nanoparticles with different shapes can be prepared by simply changing the reaction conditions. It is considered that a slow reduction of the gold ions along with shape-directed effects of the components of the detergent plays a vital function in the formation of the gold nanostructures. Further, the as-prepared gold nanoparticles showed the catalytic activity for the reduction reaction of 4-nitrophenol in the presence of sodium borohydride at room temperature. PMID:21974964

  13. Quantitative Scanning Transmission Electron Microscopy of Electronic and Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Yankovich, Andrew B.

    Electronic and nanostructured materials have been investigated using advanced scanning transmission electron microscopy (STEM) techniques. The first topic is the microstructure of Ga and Sb-doped ZnO. Ga-doped ZnO is a candidate transparent conducting oxide material. The microstructure of GZO thin films grown by MBE under different growth conditions and different substrates were examined using various electron microscopy (EM) techniques. The microstructure, prevalent defects, and polarity in these films strongly depend on the growth conditions and substrate. Sb-doped ZnO nanowires have been shown to be the first route to stable p-type ZnO. Using Z-contrast STEM, I have showed that an unusual microstructure of Sb-decorated head-to-head inversion domain boundaries and internal voids contain all the Sb in the nanowires and cause the p-type conduction. InGaN thin films and InGaN / GaN quantum wells (QW) for light emitting diodes are the second topic. Low-dose Z-contrast STEM, PACBED, and EDS on InGaN QW LED structures grown by MOCVD show no evidence for nanoscale composition variations, contradicting previous reports. In addition, a new extended defect in GaN and InGaN was discovered. The defect consists of a faceted pyramid-shaped void that produces a threading dislocation along the [0001] growth direction, and is likely caused by carbon contamination during growth. Non-rigid registration (NRR) and high-precision STEM of nanoparticles is the final topic. NRR is a new image processing technique that corrects distortions arising from the serial nature of STEM acquisition that previously limited the precision of locating atomic columns and counting the number of atoms in images. NRR was used to demonstrate sub-picometer precision in STEM images of single crystal Si and GaN, the best achieved in EM. NRR was used to measure the atomic surface structure of Pt nanoacatalysts and Au nanoparticles, which revealed new bond length variation phenomenon of surface atoms. In

  14. Functional and Regulatory Biomolecular Networks Organized by DNA Nanostructures

    NASA Astrophysics Data System (ADS)

    Liu, Minghui

    DNA has recently emerged as an extremely promising material to organize molecules on nanoscale. The reliability of base recognition, self-assembling behavior, and attractive structural properties of DNA are of unparalleled value in systems of this size. DNA scaffolds have already been used to organize a variety of molecules including nanoparticles and proteins. New protein-DNA bio-conjugation chemistries make it possible to precisely position proteins and other biomolecules on underlying DNA scaffolds, generating multi-biomolecule pathways with the ability to modulate intermolecular interactions and the local environment. This dissertation focuses on studying the application of using DNA nanostructure to direct the self-assembly of other biomolecular networks to translate biochemical pathways to non-cellular environments. Presented here are a series of studies toward this application. First, a novel strategy utilized DNA origami as a scaffold to arrange spherical virus capsids into one-dimensional arrays with precise nanoscale positioning. This hierarchical self-assembly allows us to position the virus particles with unprecedented control and allows the future construction of integrated multi-component systems from biological scaffolds using the power of rationally engineered DNA nanostructures. Next, discrete glucose oxidase (GOx)/ horseradish peroxidase (HRP) enzyme pairs were organized on DNA origami tiles with controlled interenzyme spacing and position. This study revealed two different distance-dependent kinetic processes associated with the assembled enzyme pairs. Finally, a tweezer-like DNA nanodevice was designed and constructed to actuate the activity of an enzyme/cofactor pair. Using this approach, several cycles of externally controlled enzyme inhibition and activation were successfully demonstrated. This principle of responsive enzyme nanodevices may be used to regulate other types of enzymes and to introduce feedback or feed-forward control loops.

  15. Reliable contact fabrication on nanostructured Bi2Te3-based thermoelectric materials.

    PubMed

    Feng, Shien-Ping; Chang, Ya-Huei; Yang, Jian; Poudel, Bed; Yu, Bo; Ren, Zhifeng; Chen, Gang

    2013-05-14

    A cost-effective and reliable Ni-Au contact on nanostructured Bi2Te3-based alloys for a solar thermoelectric generator (STEG) is reported. The use of MPS SAMs creates a strong covalent binding and more nucleation sites with even distribution for electroplating contact electrodes on nanostructured thermoelectric materials. A reliable high-performance flat-panel STEG can be obtained by using this new method. PMID:23531997

  16. Reliable contact fabrication on nanostructured Bi2Te3-based thermoelectric materials.

    PubMed

    Feng, Shien-Ping; Chang, Ya-Huei; Yang, Jian; Poudel, Bed; Yu, Bo; Ren, Zhifeng; Chen, Gang

    2013-05-14

    A cost-effective and reliable Ni-Au contact on nanostructured Bi2Te3-based alloys for a solar thermoelectric generator (STEG) is reported. The use of MPS SAMs creates a strong covalent binding and more nucleation sites with even distribution for electroplating contact electrodes on nanostructured thermoelectric materials. A reliable high-performance flat-panel STEG can be obtained by using this new method.

  17. Protocol for sortase-mediated construction of DNA-protein hybrids and functional nanostructures.

    PubMed

    Koussa, Mounir A; Sotomayor, Marcos; Wong, Wesley P

    2014-05-15

    Recent methods in DNA nanotechnology are enabling the creation of intricate nanostructures through the use of programmable, bottom-up self-assembly. However, structures consisting only of DNA are limited in their ability to act on other biomolecules. Proteins, on the other hand, perform a variety of functions on biological materials, but directed control of the self-assembly process remains a challenge. While DNA-protein hybrids have the potential to provide the best-of-both-worlds, they can be difficult to create as many of the conventional techniques for linking proteins to DNA render proteins dysfunctional. We present here a sortase-based protocol for covalently coupling proteins to DNA with minimal disturbance to protein function. To accomplish this we have developed a two-step process. First, a small synthetic peptide is bioorthogonally and covalently coupled to a DNA oligo using click chemistry. Next, the DNA-peptide chimera is covalently linked to a protein of interest under protein-compatible conditions using the enzyme sortase. Our protocol allows for the simple coupling and purification of a functional DNA-protein hybrid. We use this technique to form oligos bearing cadherin-23 and protocadherin-15 protein fragments. Upon incorporation into a linear M13 scaffold, these protein-DNA hybrids serve as the gate to a binary nanoswitch. The outlined protocol is reliable and modular, facilitating the construction of libraries of oligos and proteins that can be combined to form functional DNA-protein nanostructures. These structures will enable a new class of functional nanostructures, which could be used for therapeutic and industrial processes. PMID:24568941

  18. Protocol for sortase-mediated construction of DNA-protein hybrids and functional nanostructures

    PubMed Central

    Koussa, Mounir A.; Sotomayor, Marcos; Wong, Wesley P.

    2014-01-01

    Recent methods in DNA nanotechnology are enabling the creation of intricate nanostructures through the use of programmable, bottom-up self-assembly. However, structures consisting only of DNA are limited in their ability to act on other biomolecules. Proteins, on the other hand, perform a variety of functions on biological materials, but directed control of the self-assembly process remains a challenge. While DNA-protein hybrids have the potential to provide the best-of-both-worlds, they can be difficult to create as many of the conventional techniques for linking proteins to DNA render proteins dysfunctional. We present here a sortase-based protocol for covalently coupling proteins to DNA with minimal disturbance to protein function. To accomplish this we have developed a two-step process. First, a small synthetic peptide is bioorthogonally and covalently coupled to a DNA oligo using click chemistry. Next, the DNA-peptide chimera is covalently linked to a protein of interest under protein-compatible conditions using the enzyme sortase. Our protocol allows for the simple coupling and purification of a functional DNA-protein hybrid. We use this technique to form oligos bearing cadherin-23 and protocadherin-15 protein fragments. Upon incorporation into a linear M13 scaffold, these protein-DNA hybrids serve as the gate to a binary nanoswitch. The outlined protocol is reliable and modular, facilitating the construction of libraries of oligos and proteins that can be combined to form functional DNA-protein nanostructures. These structures will enable a new class of functional nanostructures, which could be used for therapeutic and industrial processes. PMID:24568941

  19. Basic principles for rational design of high-performance nanostructured silicon-based thermoelectric materials.

    PubMed

    Yang, Chun Cheng; Li, Sean

    2011-12-23

    Recently, nanostructured silicon-based thermoelectric materials have drawn great attention owing to their excellent thermoelectric performance in the temperature range around 450 °C, which is eminently applicable for concentrated solar thermal technology. In this work, a unified nanothermodynamic model is developed to investigate the predominant factors that determine the lattice thermal conductivity of nanocrystalline, nanoporous, and nanostructured bulk Si. A systematic study shows that the thermoelectric performance of these materials can be substantially enhanced by the following three basic principles: 1) artificial manipulation and optimization of roughness with surface/interface patterning/engineering; 2) grain-size reduction with innovative fabrication techniques in a controllable fashion; and 3) optimization of material parameters, such as bulk solid-vapor transition entropy, bulk vibrational entropy, dimensionality, and porosity, to decrease the lattice thermal conductivity. These principles may be used to rationally design novel nanostructured Si-based thermoelectric materials for renewable energy applications.

  20. Recent Advances in the Synthesis and Functions of Reconfigurable Interlocked DNA Nanostructures.

    PubMed

    Lu, Chun-Hua; Cecconello, Alessandro; Willner, Itamar

    2016-04-27

    Interlocked circular DNA nanostructures, e.g., catenanes or rotaxanes, provide functional materials within the area of DNA nanotechnology. Specifically, the triggered reversible reconfiguration of the catenane or rotaxane structures provides a means to yield new DNA switches and to use them as dynamic scaffolds for controlling chemical functions and positioning functional cargoes. The synthesis of two-ring catenanes and their switchable reconfiguration by pH, metal ions, or fuel/anti-fuel stimuli are presented, and the functions of these systems, as pendulum or rotor devices or as switchable catalysts, are described. Also, the synthesis of three-, five-, and seven-ring catenanes is presented, and their switchable reconfiguration using fuel/anti-fuel strands is addressed. Implementation of the dynamically reconfigured catenane structures for the programmed organization of Au nanoparticle (NP) assemblies, which allows the plasmonic control of the fluorescence properties of Au NP/fluorophore loads associated with the scaffold, and for the operation of logic gates is discussed. Interlocked DNA rotaxanes and their different synthetic approaches are presented, and their switchable reconfiguration by means of fuel/anti-fuel strands or photonic stimuli is described. Specifically, the use of the rotaxane as a scaffold to organize Au NP assemblies, and the control of the fluorescence properties with Au NP/fluorophore hybrids loaded on the rotaxane scaffold, are introduced. The future prospectives and challenges in the field of interlocked DNA nanostructures and the possible applications are discussed. PMID:27019201

  1. 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.

  2. Ultra-sensitive immunoassay biosensors using hybrid plasmonic-biosilica nanostructured materials.

    PubMed

    Yang, Jing; Zhen, Le; Ren, Fanghui; Campbell, Jeremy; Rorrer, Gregory L; Wang, Alan X

    2015-08-01

    We experimentally demonstrate an ultra-sensitive immunoassay biosensor using diatom biosilica with self-assembled plasmonic nanoparticles. As the nature-created photonic crystal structures, diatoms have been adopted to enhance surface plasmon resonances of metal nanoparticles on the surfaces of diatom frustules and to increase the sensitivity of surface-enhanced Raman scattering (SERS). In this study, a sandwich SERS immunoassay is developed based on the hybrid plasmonic-biosilica nanostructured materials that are functionalized with goat anti-mouse IgG. Our experimental results show that diatom frustules improve the detection limit of mouse IgG to 10 pg/mL, which is ˜100× better than conventional colloidal SERS sensors on flat glass. Ultra-sensitive immunoassay biosensor using diatom biosilica with self-assembled plasmonic nanoparticles.

  3. Plasmonic nanorods provide reversible control over nanostructure of self-assembled drug delivery materials.

    PubMed

    Fong, Wye-Khay; Hanley, Tracey L; Thierry, Benjamin; Kirby, Nigel; Boyd, Ben J

    2010-05-01

    The nanostructure of mesophase liquid crystals prepared from amphiphilic lipids controls the rate of release of incorporated agents from the material, such as drug molecules, and reversible transition between different nanostructures essentially provides an "on-off" switch for release (Fong, W.-K.; Hanley, T.; Boyd, B. J. J. Controlled Release 2009, 135, 218-226). In this study, the incorporation of plasmonic hydrophobized gold nanorods (GNRs) permits reversible manipulation of nanostructure on-demand, by irradiation of the matrix using a near-infrared laser. Synchrotron small-angle X-ray scattering was used to probe the kinetics of the response of nanostructure to laser irradiation, and the specificity of the approach is shown by the lack of response in the absence of nanorods, or for GNR whose dimensions are not matched to the specific wavelength of the incident light.

  4. Functional Metal Oxide Nanostructures: Their Synthesis, Characterization, and Energy Applications

    NASA Astrophysics Data System (ADS)

    Iyer, Aparna

    in oxidation reactions and adsorption of heavy metal. Spontaneous formation of OMS-2 nanospheres was possible by tuning reaction parameters in the ultrasonic atomization process. In the second part, a microwave-hydrothermal route has been developed for the synthesis of 1D cobalt compounds (Chapter 5). These compounds are transformed to spinel type Co3O4 nanorods. The effects of solvents, cobalt sources, and microwave radiation time in the formation of 1D cobalt oxide nanostructures were studied in detail. These materials are catalytically active for CO oxidation and styrene oxidation reactions. Magnesia-yttria nanocomposites with controlled nanoscale grain sizes and homogenous microstructures are useful as IR transparent materials. A simple cost-effective sucrose based sol-gel route was devised for making MgO-Y 2O3 nanocomposites. Grain growth in these nanocomposites was systematically evaluated using transmission electron microscopy studies.

  5. Transformational, Large Area Fabrication of Nanostructured Materials Using Plasma Arc Lamps

    SciTech Connect

    2009-03-01

    This factsheet describes a study that will address critical additional steps over large areas of as-synthesized nanostructured materials, such as annealing, phase transformation, or activation of dopants, dramatically reducing the processing costs of the solid-state lighting and photovoltaic materials.

  6. Simulation of electromagnetic radiation passing through liquid-containing nanostructured materials

    NASA Astrophysics Data System (ADS)

    Kolbun, Natallia V.; Borbotko, Timophey V.; Kazeka, Alexandr A.; Proudnik, Alexander M.; Lynkou, Leanid M.

    2008-07-01

    A process of electromagnetic radiation traveling through liquid-containing nanostructured heterogeneous materials was simulated. Mobile phone antenna pattern is calculated and its change when applying protective shield made of said materials is studied. Transmission/reflection characteristics of antenna are calculated.

  7. Magnesium ion implantation on a micro/nanostructured titanium surface promotes its bioactivity and osteogenic differentiation function

    PubMed Central

    Wang, Guifang; Li, Jinhua; Zhang, Wenjie; Xu, Lianyi; Pan, Hongya; Wen, Jin; Wu, Qianju; She, Wenjun; Jiao, Ting; Liu, Xuanyong; Jiang, Xinquan

    2014-01-01

    As one of the important ions associated with bone osseointegration, magnesium was incorporated into a micro/nanostructured titanium surface using a magnesium plasma immersion ion-implantation method. Hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 30 minutes (Mg30) and hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 60 minutes (Mg60) were used as test groups. The surface morphology, chemical properties, and amount of magnesium ions released were evaluated by field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, field-emission transmission electron microscopy, and inductively coupled plasma-optical emission spectrometry. Rat bone marrow mesenchymal stem cells (rBMMSCs) were used to evaluate cell responses, including proliferation, spreading, and osteogenic differentiation on the surface of the material or in their medium extraction. Greater increases in the spreading and proliferation ability of rBMMSCs were observed on the surfaces of magnesium-implanted micro/nanostructures compared with the control plates. Furthermore, the osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP) genes were upregulated on both surfaces and in their medium extractions. The enhanced cell responses were correlated with increasing concentrations of magnesium ions, indicating that the osteoblastic differentiation of rBMMSCs was stimulated through the magnesium ion function. The magnesium ion-implanted micro/nanostructured titanium surfaces could enhance the proliferation, spreading, and osteogenic differentiation activity of rBMMSCs, suggesting they have potential application in improving bone-titanium integration. PMID:24940056

  8. First Principles Investigations of Technologically and Environmentally Important Nano-structured Materials and Devices

    NASA Astrophysics Data System (ADS)

    Paul, Sujata

    In the course of my PhD I have worked on a broad range of problems using simulations from first principles: from catalysis and chemical reactions at surfaces and on nanostructures, characterization of carbon-based systems and devices, and surface and interface physics. My research activities focused on the application of ab-initio electronic structure techniques to the theoretical study of important aspects of the physics and chemistry of materials for energy and environmental applications and nano-electronic devices. A common theme of my research is the computational study of chemical reactions of environmentally important molecules (CO, CO2) using high performance simulations. In particular, my principal aim was to design novel nano-structured functional catalytic surfaces and interfaces for environmentally relevant remediation and recycling reactions, with particular attention to the management of carbon dioxide. We have studied the carbon-mediated partial sequestration and selective oxidation of carbon monoxide (CO), both in the presence and absence of hydrogen, on graphitic edges. Using first-principles calculations we have studied several reactions of CO with carbon nanostructures, where the active sites can be regenerated by the deposition of carbon decomposed from the reactant (CO) to make the reactions self-sustained. Using statistical mechanics, we have also studied the conditions under which the conversion of CO to graphene and carbon dioxide is thermodynamically favorable, both in the presence and in the absence of hydrogen. These results are a first step toward the development of processes for the carbon-mediated partial sequestration and selective oxidation of CO in a hydrogen atmosphere. We have elucidated the atomic scale mechanisms of activation and reduction of carbon dioxide on specifically designed catalytic surfaces via the rational manipulation of the surface properties that can be achieved by combining transition metal thin films on oxide

  9. Processing and nanostructure influences on mechanical properties of thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Schmidt, Robert David

    Thermoelectric (TE) materials are materials that can generate an electric current from a thermal gradient, with possible service in recovery of waste heat such as engine exhaust. Significant progress has been made in improving TE conversion efficiency, typically reported according to the figure of merit, ZT, with several recent papers publishing ZT values above 2. Furthermore, cost reductions may be made by the use of lower cost elements such as Mg, Si, Sn, Pb, Se and S in TE materials, while achieving ZT values between 1.3 and 1.8. To be used in a device, the thermoelectric material must be able to withstand the applied thermal and mechanical forces without failure. However, these materials are brittle, with low fracture toughness typically less than 1.5 MPa-m1/2, and often less than 0.5 MPa-m1/2. For comparison, window glass is approximately 0.75 MPa-m1/2. They have been optimized with nanoprecipitates, nanoparticles, doping, alterations in stoichiometry, powder processing and other techniques, all of which may alter the mechanical properties. In this study, the effect of SiC nanoparticle additions in Mg2Si, SnTe and Ag nanoparticle additions in the skutterudite Ba0.3Co 4Sb12 on the elastic moduli, hardness and fracture toughness are measured. Large changes (˜20%) in the elastic moduli in SnTe 1+x as a function of x at 0 and 0.016 are shown. The effect on mechanical properties of doping and precipitates of CdS or ZnS in a PbS or PbSe matrix have been reported. Changes in sintering behavior of the skutterudite with the Ag nanoparticle additions were explored. Possible liquid phase sintering, with associated benefits in lower processing temperature, faster densification and lower cost, has been shown. A technique has been proposed for determining additional liquid phase sintering aids in other TE materials. The effects of porosity, grain size, powder processing method, and sintering method were explored with YbAl3 and Ba0.3Co4Sb 12, with the porosity dependence of

  10. 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.

  11. PROPERTIES AND NANOSTRUCTURES OF NANO-MATERIALS PROCESSED BY SEVERE PLASTIC DEFORMATION (SPD).

    SciTech Connect

    Zhu, Y. T.

    2001-01-01

    Metallic materials usually exhibit higher strength but lower ductility after being plastically deformed by conventional techniques such as rolling, drawing and extrusion. In contrast, nanostructured metals and alloys processed by severe plastic deformation (SPD) have demonstrated both high strength and high ductility. This extraordinary mechanical behavior is attributed to the unique nanostructures generated by SPD processing. The combination of ultrafine grain size and high-density dislocations appears to enable deformation by new mechanisms not active in coarse-grained metals and alloys. These results demonstrate the possibility of tailoring the microstructures of metals and alloys by SPD to obtain superior mechanical properties. Nanostructured metals and alloys processed by SPD techniques have unique nanostructures not observed in nanomaterials synthesized by other techniques such as the consolidation of nanopowders. The SPD-generated nanostructures have many features related to deformation, including high dislocation densities, and high- and low-angle grain boundaries in equilibrium or nonequilibrium states. Future studies are needed to investigate the deformation mechanisms that relate the unique nanostructures with the superior mechanical properties exhibited by SPD-processed metals and alloys.

  12. Nanostructured membranes and electrodes with sulfonic acid functionalized carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Tripathi, Bijay P.; Schieda, M.; Shahi, Vinod K.; Nunes, Suzana P.

    Herein we report the covalent functionalization of multiwall carbon nanotubes by grafting sulfanilic acid and their dispersion into sulfonated poly(ether ether ketone). The nanocomposites were explored as an option for tuning the proton and electron conductivity, swelling, water and alcohol permeability aiming at nanostructured membranes and electrodes for application in alcohol or hydrogen fuel cells and other electrochemical devices. The nanocomposites were extensively characterized, by studying their physicochemical and electrochemical properties. They were processed as self-supporting films with high mechanical stability, proton conductivity of 4.47 × 10 -2 S cm -1 at 30 °C and 16.8 × 10 -2 S cm -1 at 80 °C and 100% humidity level, electron conductivity much higher than for the plain polymer. The methanol permeability could be reduced to 1/20, keeping water permeability at reasonable values. The ratio of bound water also increases with increasing content of sulfonated filler, helping in keeping water in the polymer in conditions of low external humidity level.

  13. Covalent functionalization of metal oxide and carbon nanostructures with polyoctasilsesquioxane (POSS) and their incorporation in polymer composites

    SciTech Connect

    Gomathi, A.; Gopalakrishnan, K.; Rao, C.N.R.

    2010-12-15

    Polyoctasilsesquioxane (POSS) has been employed to covalently functionalize nanostructures of TiO{sub 2}, ZnO and Fe{sub 2}O{sub 3} as well as carbon nanotubes, nanodiamond and graphene to enable their dispersion in polar solvents. Covalent functionalization of these nanostructures with POSS has been established by electron microscopy, EDAX analysis and infrared spectroscopy. On heating the POSS-functionalized nanostructures, silica-coated nanostructures are obtained. POSS-functionalized nanoparticles of TiO{sub 2}, Fe{sub 2}O{sub 3} and graphite were utilized to prepare polymer-nanostructure composites based on PVA and nylon-6,6.

  14. Micro- and Nanostructured Materials for Active Devices and Molecular Electronics

    SciTech Connect

    Martin, Peter M.; Graff, Gordon L.; Gross, Mark E.; Burrows, Paul E.; Bennett, Wendy D.; Mast, Eric S.; Hall, Michael G.; Bonham, Charles C.; Zumhoff, Mac R.; Williford, Rick E.

    2003-10-01

    Traditional single layer barrier coatings are not adequate in preventing degradation of the performance of organic molecular electronic and other active devices. Most advanced devices used in display technology now consist of micro and nanostructured small molecule, polymer and inorganic coatings with thin high reactive group 1A metals. This includes organic electronics such as organic light emitting devices (OLED). The lifetimes of these devices rapidly degrades when they are exposed to atmospheric oxygen and water vapor. Thin film photovoltaics and batteries are also susceptible to degradation by moisture and oxygen. Using in-line coating techniques we apply a composite nanostructured inorganic/polymer thin film barrier that restricts moisture and oxygen permeation to undetectable levels using conventional permeation test equipment. We describe permeation mechanisms for this encapsulation coating and flat panel display and other device applications. Permeation through the multilayer barrier coating is defect and pore limited and can be described by Knudsen diffusion involving a long and tortuous path. Device lifetime is also enhanced by the long lag times required to reach the steady state flux regime. Permeation rates in the range of 10-6 cc,g/m2/d have been achieved and OLED device lifetimes. The structure is robust, yet flexible. The resulting device performance and lifetimes will also be described. The barrier film can be capped with a thin film of transparent conductive oxide yielding an engineered nanostructured device for next generation, rugged, lightweight or flexible displays. This enables, for the first time, thin film encapsulation of emissive organic displays.

  15. Nano-structured carbon materials for improved biosensing applications

    NASA Astrophysics Data System (ADS)

    Razumiene, J.; Sakinyte, I.; Barkauskas, J.; Baronas, R.

    2015-04-01

    A set of oxidized graphite samples have been newly synthesized using different protocols. Atomic force microscopy, Raman spectroscopy, thermal gravimetric analysis and Brunauer-Emmett-Teller analysis revealed the changes in structure and functionalities of obtained graphite oxidation products (GOPs) compared to pristine graphite. The substances have been tested as electrode materials applicable for bioelectrocatalytic systems using pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH). The application of GOPs allowed achieving the direct electron transfer (DET) from active site of PQQ-GDH to the electrode surface. Needless of additional electron transfer (ET) mediating compounds highly improved features of the biosensors. The efficiency of the biosensors has been evaluated for all types of biosensors varied from 32 μA/cm2 to 64 μA/cm2 using as electrode materials GOP1 and thermally reduced graphite oxide (TRGO), respectively. TRGO containing function groups (according TGA, ∼6% of the weight loss) and smallest particles (average diameter was ∼11 nm and the average height was ∼0.5 nm) exhibited the higher efficiency for ET acceleration in the biosensor acting on principle of DET.

  16. Thermoelectric and thermospintronic transport in Dirac material-based nanostructures

    NASA Astrophysics Data System (ADS)

    Chang, Po-Hao

    The growing need for power due to the rapid developments of the technologies has urged both engineers and scientists to study more sustainable types of energy. On the other hand, the improvement of our abilities although enable us, for example, to double the number of transistors in a dense integrated circuit approximately every two years (Moore's law), comes with side effect due to overheating. Taking advantage of thermoelectric effect has thus become one of the obvious solutions for the problems. But due to the poor efficiency of electricity-heat conversion, there are still challenges to be overcome in order to fully utilize the idea. In the past few years, the realization of graphene along with the discoveries of topological insulators (TI) which are both considered as Dirac material (DM) have offer alternative routs for improving the energy conversion efficiency through different approaches as well as novel quantum effects of materials themselves for investigation. The aim of this thesis is to present contributions to improving the efficiency of thermoelectric conversion as well as analyzing spin transport phenomena that occur in nano-devices. This thesis spans the areas of thermoelectric (TE) effect, spin-Seebeck effect (SSE) and the spin transport on the 3D topological insulator (TI). The different methods have been applied ranging from tight-binding (TB) approximation to density function theory (DFT) combined with non-equilibrium function (NEGF) techniques.

  17. 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.

  18. Anti-reflective conducting indium oxide layer on nanostructured substrate as a function of aspect ratio

    NASA Astrophysics Data System (ADS)

    Park, Hyun-Woo; Ji, Seungmuk; Lim, Hyuneui; Choi, Dong-won; Park, Jin-Seong; Chung, Kwun-Bum

    2016-09-01

    Antireflective conducting indium oxide layers were deposited using atomic layer deposition on a transparent nanostructured substrate grown using colloidal lithography. In order to explain the changes in the electrical resistivity and the optical transmittance of conducting indium oxide layers depending on various aspect ratios of the nanostructured substrates, we investigated the surface area and refractive index of the indium oxide layers in the film depth direction as a function of aspect ratio. The conformal indium oxide layer on a transparent nanostructured substrate with optimized geometry exhibited transmittance of 88% and resistivity of 7.32 × 10-4 Ω cm. The enhancement of electrical resistivity is strongly correlated with the surface area of the indium oxide layer depending on the aspect ratio of the nanostructured substrates. In addition, the improvement in transparency was explained by the gradual changes of the refractive index in the film depth direction according to the aspect ratio of the nanostructures.

  19. 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.

  20. 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.

  1. A risk forecasting process for nanostructured materials, and nanomanufacturing

    NASA Astrophysics Data System (ADS)

    Wiesner, Mark R.; Bottero, Jean-Yves

    2011-09-01

    Nanomaterials exhibit novel properties that enable new applications ranging from molecular electronics to energy production. Proactive consideration of the potential impacts on human health and the environment resulting from nanomaterial production and use requires methods for forecasting risk associated with of these novel materials. However, the potential variety of nanomaterials is virtually infinite and a case-by-case analysis of the risks these materials may pose is not possible. The challenge of forecasting risk for a broad number of materials is further complicated by large degrees of uncertainty concerning production amounts, the characteristics and uses of these materials, exposure pathways, and a scarcity of data concerning the relationship between nanomaterial characteristics and their effects on organisms and ecosystems. A traditional risk assessment on nanomaterials is therefore not possible at this time. In its place, an evolving process is needed for analyzing the risks associated with emerging nanomaterials-related industries. In this communication, we propose that such a process should include the following six key features: (1) the ability to generate forecasts and associated levels of uncertainty for questions of immediate concern; (2) a consideration of all pertinent sources of nanomaterials; (3) an inclusive consideration of the impacts of activities stemming from nanomaterial use and production that extends beyond the boundaries of toxicology and include full life cycle impacts; (4) the ability to adapt and update risk forecasts as new information becomes available; (5) feedback to improve information gathering; and (6) feedback to improve nanomaterial design. Feature #6 implies that the potential risks of nanomaterials must ultimately be determined as a function of fundamental, quantifiable properties of nanomaterials, so that when these properties are observed in a new material, they can be recognized as indicators of risk. Thus, the

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Characterisation and tribological investigation on thermally processed nanostructured Fe-based and Cu-based cermet materials.

    PubMed

    Basak, A K; Eddine, W Zein; Celis, J P; Matteazzi, P

    2010-02-01

    The feasibility of achieving a nanostructured material after different thermal processing of nanosized powders is presented. The thermal processing was done by either atmospheric plasma spraying, laser sintering, or extrusion followed by hot isostatic pressing. The structural characterisation of such thermally processed nanostructured Fe-based and Cu-based metallic or Al2O3 reinforced cermets, confirmed the retention of a nanostructure after each of these thermal processes. Hardness measurements confirmed an increased hardness as expected in the case that nanostructuring is achieved. The role of grain boundaries and second phase particles on the retention of the nanostructure after thermal processing is discussed. Finally, the possible benefit of nanostructuring on the friction and wear behaviour of materials in sliding tests against corundum in ambient air is reported and discussed. PMID:20352775

  8. 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.

  9. Nanostructured polyoxometalate arrays with unprecedented properties and functions.

    SciTech Connect

    Dunphy, Darren Robert; Brinker, C. Jeffrey; Singh, Seema; Nyman, May Devan

    2003-11-01

    Polyoxometalates (POMs) are ionic (usually anionic) metal -oxo clusters that are both functional entities for a variety of applications, as well as structural units that can be used as building blocks if reacted under appropriate conditions. This is a powerful combination in that functionality can be built into materials, or doped into matrices. Additionally, by assembling functional POMs in ordered materials, new collective behaviors may be realized. Further, the vast variety of POM geometries, compositions and charges that are achievable gives this system a high degree of tunability. Processing conditions to link together POMs to build materials offer another vector of control, thus providing infinite possibilities of materials that can he nano-engineered through POM building blocks. POM applications that can be built into POM-based materials include catalysis, electro-optic and electro-chromic, anti-viral, metal binding, and protein binding. We have begun to explore three approaches in developing this field of functional, nano-engineered POM-based materials; and this report summarizes the work carried out for these approaches to date. The three strategies are: (1) doping POMs into silica matrices using sol-gel science, (2) forming POM-surfactant arrays and metal-POM-surfactant arrays, (3) using aerosol-spray pyrolysis of the POM-surfactant arrays to superimpose hierarchical architecture by self-assembly during aerosol-processing. Doping POMs into silica matrices was successful, but the POMs were partially degraded upon attempts to remove the structure-directing templates. The POM-surfactant and metal-POM-surfactant arrays approach was highly successful and holds much promise as a novel approach to nano-engineering new materials from structural and functional POM building blocks, as well as forming metastable or unusual POM geometries that may not be obtained by other synthetic methods. The aerosol-assisted self assembly approach is in very preliminary state of

  10. Thermal evaporation furnace with improved configuration for growing nanostructured inorganic materials.

    PubMed

    Joanni, E; Savu, R; Valadares, L; Cilense, M; Zaghete, M A

    2011-06-01

    A tubular furnace specifically designed for growing nanostructured materials is presented in this work. The configuration allows an accurate control of evaporation temperature, substrate temperature, total pressure, oxygen partial pressure, volumetric flow and source-substrate distance, with the possibility of performing both downstream and upstream depositions. In order to illustrate the versatility of the equipment, the furnace was used for growing semiconducting oxide nanostructures under different deposition conditions. Highly crystalline indium oxide nanowires with different morphologies were synthesized by evaporating mixtures of indium oxide and graphite powders with different mass ratios at temperatures between 900 °C and 1050 °C. The nanostructured layers were deposited onto oxidized silicon substrates with patterned gold catalyst in the temperature range from 600 °C to 900 °C. Gas sensors based on these nanowires exhibited enhanced sensitivity towards oxygen, with good response and recovery times. PMID:21721724

  11. 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.

  12. 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.

  13. Aerosol Route Synthesis and Applications of Doped Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Sahu, Manoranjan

    Nanotechnology presents an attractive opportunity to address various challenges in air and water purification, energy, and other environment issues. Thus, the development of new nanoscale materials in low-cost scalable synthesis processes is important. Furthermore, the ability to independently manipulate the material properties as well as characterize the material at different steps along the synthesis route will aide in product optimization. In addition, to ensure safe and sustainable development of nanotechnology applications, potential impacts need to be evaluated. In this study, nanomaterial synthesis in a single-step gas phase reactor to continuously produce doped metal oxides was demonstrated. Copper-doped TiO2 nanomaterial properties (composition, size, and crystal phase) were independently controlled based on nanoparticle formation and growth mechanisms dictated by process control parameters. Copper dopant found to significantly affect TiO2 properties such as particle size, crystal phase, stability in the suspension, and absorption spectrum (shift from UV to visible light absorption). The in-situ charge distribution characterization of the synthesized nanomaterials was carried out by integrating a tandem differential mobility analyzer (TDMA) set up with the flame reactor synthesis system. Both singly- and doubly- charged nanoparticles were measured, with the charged fractions dependent on particle mobility and dopant concentration. A theoretical calculation was conducted to evaluate the relative importance of the two charging mechanisms, diffusion and thermo-ionization, in the flame. Nanoparticle exposure characterization was conducted during synthesis as a function of operating condition, product recovery and handling technique, and during maintenance of the reactors. Strategies were then indentified to minimize the exposure risk. The nanoparticle exposure potential varied depending on the operating conditions such as precursor feed rate, working

  14. The total scattering atomic pair distribution function: New methodology for nanostructure analysis

    NASA Astrophysics Data System (ADS)

    Masadeh, Ahmad

    The conventional xray diffration (XRD) methods probe for the presence of long-range order (periodic structure) which are reflected in the Bragg peaks. Local structural deviations or disorder mainly affect the diffuse scattering intensity. In order to obtain structural information about both long-range order and local structure disorder, a technique that takes in account both Bragg and diffuse scattering need to be employed, such as the atomic pair distribution function (PDF) technique. This work introduces a PDF based methodology to quantitatively investigate nanostructure materials in general. The introduced methodology can be applied to extract quantitatively structural information about structure, crystallinity level, core/shell size, nanoparticle size, and inhomogeneous internal strain in the measured nanoparticles. This method is generally applicable to the characterization of the nano-scale solid, many of which may exhibit complex disorder and strain

  15. Sustainable approach toward synthesis of green functional carbonaceous 3-D micro/nanostructures from biomass

    PubMed Central

    2013-01-01

    This study proposes a novel technique to synthesize functional carbonaceous three-dimensional (3-D) micro/nanocompounds from agricultural by-products using femtosecond laser irradiation. Biowastes of rice husk and wheat straw are value-engineered to carbonaceous structures in a single-step process under ambient conditions. Our results demonstrate that by controlling the laser fluence, structures with a variety of different morphologies from nanostructures to microstructures can be achieved. Also, the results indicate that altering the laser processing parameters influences the chemical composition of the synthesized structures. This sustainable approach presents an important step towards synthesizing 3-D micro/nanofibrous compounds from biowaste materials. These structures, as-synthesized or as nanocomposite fillers, can have practical uses in electronic, sensing, biological, and environmental applications. PMID:23924310

  16. Sustainable approach toward synthesis of green functional carbonaceous 3-D micro/nanostructures from biomass.

    PubMed

    Tavangar, Amirhossein; Tan, Bo; Venkatakrishnan, Krishnan

    2013-01-01

    This study proposes a novel technique to synthesize functional carbonaceous three-dimensional (3-D) micro/nanocompounds from agricultural by-products using femtosecond laser irradiation. Biowastes of rice husk and wheat straw are value-engineered to carbonaceous structures in a single-step process under ambient conditions. Our results demonstrate that by controlling the laser fluence, structures with a variety of different morphologies from nanostructures to microstructures can be achieved. Also, the results indicate that altering the laser processing parameters influences the chemical composition of the synthesized structures. This sustainable approach presents an important step towards synthesizing 3-D micro/nanofibrous compounds from biowaste materials. These structures, as-synthesized or as nanocomposite fillers, can have practical uses in electronic, sensing, biological, and environmental applications. PMID:23924310

  17. Sustainable approach toward synthesis of green functional carbonaceous 3-D micro/nanostructures from biomass

    NASA Astrophysics Data System (ADS)

    Tavangar, Amirhossein; Tan, Bo; Venkatakrishnan, Krishnan

    2013-08-01

    This study proposes a novel technique to synthesize functional carbonaceous three-dimensional (3-D) micro/nanocompounds from agricultural by-products using femtosecond laser irradiation. Biowastes of rice husk and wheat straw are value-engineered to carbonaceous structures in a single-step process under ambient conditions. Our results demonstrate that by controlling the laser fluence, structures with a variety of different morphologies from nanostructures to microstructures can be achieved. Also, the results indicate that altering the laser processing parameters influences the chemical composition of the synthesized structures. This sustainable approach presents an important step towards synthesizing 3-D micro/nanofibrous compounds from biowaste materials. These structures, as-synthesized or as nanocomposite fillers, can have practical uses in electronic, sensing, biological, and environmental applications.

  18. 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.

  19. Nanostructured multilayered thin film barriers for Mg2Si thermoelectric materials

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    The Mg2Si-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 Mg2Si 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/Mg2Si-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. Review on recent progress of nanostructured anode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Goriparti, Subrahmanyam; Miele, Ermanno; De Angelis, Francesco; Di Fabrizio, Enzo; Proietti Zaccaria, Remo; Capiglia, Claudio

    2014-07-01

    This review highlights the recent research advances in active nanostructured anode materials for the next generation of Li-ion batteries (LIBs). In fact, in order to address both energy and power demands of secondary LIBs for future energy storage applications, it is required the development of innovative kinds of electrodes. Nanostructured materials based on carbon, metal/semiconductor, metal oxides and metal phosphides/nitrides/sulfides show a variety of admirable properties for LIBs applications such as high surface area, low diffusion distance, high electrical and ionic conductivity. Therefore, nanosized active materials are extremely promising for bridging the gap towards the realization of the next generation of LIBs with high reversible capacities, increased power capability, long cycling stability and free from safety concerns. In this review, anode materials are classified, depending on their electrochemical reaction with lithium, into three groups: intercalation/de-intercalation, alloy/de-alloy and conversion materials. Furthermore, the effect of nanoscale size and morphology on the electrochemical performance is presented. Synthesis of the nanostructures, lithium battery performance and electrode reaction mechanisms are also discussed. To conclude, the main aim of this review is to provide an organic outline of the wide range of recent research progresses and perspectives on nanosized active anode materials for future LIBs.

  1. 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.

  2. Solid-State Nanostructured Materials from Self-Assembly of a Globular Protein-Polymer Diblock Copolymer

    PubMed Central

    Thomas, Carla S.; Glassman, Matthew J.; Olsen, Bradley D.

    2014-01-01

    Self-assembly of three-dimensional solid-state nanostructures containing approximately 33% by weight globular protein is demonstrated using a globular protein-polymer diblock copolymer, providing a route to direct nanopatterning of proteins for use in bioelectronic and biocatalytic materials. A mutant red fluorescent protein, mCherryS131C, was prepared by incorporation of a unique cysteine residue and site-specifically conjugated to end-functionalized poly(N-isopropylacrylamide) through thiol-maleimide coupling to form a well-defined model protein-polymer block copolymer. The block copolymer was self-assembled into bulk nanostructures by solvent evaporation from concentrated solutions. Small-angle X-ray scattering and transmission electron microscopy illustrated the formation of highly disordered lamellae or hexagonally perforated lamellae depending upon the selectivity of the solvent during evaporation. Solvent annealing of bulk samples resulted in a transition towards lamellar nanostructures with mCherry packed in a bilayer configuration and a large improvement in long range ordering. Wide-angle X-ray scattering indicated that mCherry did not crystallize within the block copolymer nanodomains and that the β-sheet spacing was not affected by self-assembly. Circular dichroism showed no change in protein secondary structure after self-assembly, while UV-vis spectroscopy indicated approximately 35% of the chromophore remained optically active. PMID:21696135

  3. 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.

  4. n-Type nanostructured thermoelectric materials prepared from chemically synthesized ultrathin Bi2Te3 nanoplates.

    PubMed

    Son, Jae Sung; Choi, Moon Kee; Han, Mi-Kyung; Park, Kunsu; Kim, Jae-Yeol; Lim, Seong Joon; Oh, Myunghwan; Kuk, Young; Park, Chan; Kim, Sung-Jin; Hyeon, Taeghwan

    2012-02-01

    We herein report on the large-scale synthesis of ultrathin Bi(2)Te(3) nanoplates and subsequent spark plasma sintering to fabricate n-type nanostructured bulk thermoelectric materials. Bi(2)Te(3) nanoplates were synthesized by the reaction between bismuth thiolate and tri-n-octylphosphine telluride in oleylamine. The thickness of the nanoplates was ~1 nm, which corresponds to a single layer in Bi(2)Te(3) crystals. Bi(2)Te(3) nanostructured bulk materials were prepared by sintering of surfactant-removed Bi(2)Te(3) nanoplates using spark plasma sintering. We found that the grain size and density were strongly dependent on the sintering temperature, and we investigated the effect of the sintering temperature on the thermoelectric properties of the Bi(2)Te(3) nanostructured bulk materials. The electrical conductivities increased with an increase in the sintering temperature, owing to the decreased interface density arising from the grain growth and densification. The Seebeck coefficients roughly decreased with an increase in the sintering temperature. Interestingly, the electron concentrations and mobilities strongly depended on the sintering temperature, suggesting the potential barrier scattering at interfaces and the doping effect of defects and organic residues. The thermal conductivities also increased with an increase in the sintering temperature because of grain growth and densification. The maximum thermoelectric figure-of-merit, ZT, is 0.62 at 400 K, which is one of the highest among the reported values of n-type nanostructured materials based on chemically synthesized nanoparticles. This increase in ZT shows the possibility of the preparation of highly efficient thermoelectric materials by chemical synthesis.

  5. Polymeric Bicontinuous Microemulsions as Templates for Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Jones, Brad Howard

    Ternary blends of two homopolymers and a diblock copolymer can self-assemble into interpenetrating, three dimensionally-continuous networks with a characteristic length scale of ˜ 100 nm. In this thesis, it is shown that these liquid phases, known as polymeric bicontinuous microemulsions (BμE), can be designed as versatile precursors to nanoporous materials having pores with uniform sizes of ˜ 100 nm. The model blends from which the porous materials are derived are composed of polyethylene (PE) and a sacrificial polyolefin. The liquid BμE structure is captured by crystallization of the PE, and a three-dimensionally continuous pore network with a narrow pore size distribution is generated by selective extraction of the sacrificial component. The original BμE structure is retained in the resultant nanoporous PE. This monolithic material is then used as a template in the synthesis of other nanoporous materials for which structural control at the nm scale has traditionally been difficult to achieve. These materials, which include a high-temperature ceramic, polymeric thermosets, and a conducting polymer, are produced by a simple nanocasting process, providing an inverse replica of the PE template. On account of the BμE structure of the template, the product materials also possess three-dimensionally continuous pore networks with narrow size distributions centered at ˜ 100 nm. The PE template is further used as a template for the production of hierarchically structured inorganic and polymeric materials by infiltration of mesostructured compounds into its pore network. In the former case, a hierarchically porous SiO2 material is demonstrated, simultaneously possessing two discrete, bicontinuous pore networks with sizes differing by over an order of magnitude. Finally, the templating procedures are extended to thin films supported on substrates and novel conductive polymer films are synthesized. The work described herein represents an unprecedented suite of

  6. Fabrication of a nanostructured gold-polymer composite material.

    PubMed

    Mallick, K; Witcomb, M; Scurrell, M

    2006-07-01

    A facile synthesis route is described for the preparation of a poly-(o-aminophenol)-gold nanoparticle composite material by polymerization of o-aminophenol (AP) monomer using HAuCl(4) as the oxidant. The synthesis was carried out in a methanol medium so that it could serve a dual solvent role, a solvent for both the AP and the water solution of HAuCl(4). It was found that oxidative polymerization of AP leads to the formation of poly-AP with a diameter of 50+/-10nm, while the reduction of AuCl(4) (-) results in the formation of gold nanoparticles ( approximately 2nm). The gold nanoparticles were uniformly dispersed and highly stabilized throughout the macromolecular chain that formed a uniform metal-polymer composite material. The resultant composite material was characterized by means of different techniques, such as UV-vis, IR and Raman spectroscopy, which offered the information about the chemical structure of polymer, whereas electron microscopy images provided information regarding the morphology of the composite material and the distribution of the metal particles in the composite material.

  7. Ground state energy and wave function of an off-centre donor in spherical core/shell nanostructures: Dielectric mismatch and impurity position effects

    NASA Astrophysics Data System (ADS)

    Ibral, Asmaa; Zouitine, Asmae; Assaid, El Mahdi; Feddi, El Mustapha; Dujardin, Francis

    2014-09-01

    Ground state energy and wave function of a hydrogen-like off-centre donor impurity, confined anywhere in a ZnS/CdSe spherical core/shell nanostructure are determined in the framework of the envelope function approximation. Conduction band-edge alignment between core and shell of nanostructure is described by a finite height barrier. Dielectric constant mismatch at the surface where core and shell materials meet is taken into account. Electron effective mass mismatch at the inner surface between core and shell is considered. A trial wave function where coulomb attraction between electron and off-centre ionized donor is used to calculate ground state energy via the Ritz variational principle. The numerical approach developed enables access to the dependence of binding energy, coulomb correlation parameter, spatial extension and radial probability density with respect to core radius, shell radius and impurity position inside ZnS/CdSe core/shell nanostructure.

  8. Nanostructured energetic materials using sol-gel methodologies

    SciTech Connect

    Tillotson, T M; Simpson, R L; Hrubesh, L W; Gash, A E; Thomas, I M; Poco, J F

    2000-09-27

    The fundamental differences between energetic composites and energetic materials made from a monomolecular approach are the energy density attainable and the energy release rates. For the past 4 years, we have been exploiting sol-gel chemistry as a route to process energetic materials on a microstructural scale. At the last ISA conference, we described four specific sol-gel approaches to fabricating energetic materials and presented our early work and results on two methods - solution crystallization and powder addition. Here, we detail our work on a third approach, energetic nanocomposites. Synthesis of thermitic types of energetic nanocomposites are presented using transition and main group metal-oxide skeletons. Results on characterization of structure and performance will also be given.

  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. In Situ Neutron Scattering Study of Nanostructured PbTe-PbS Bulk Thermoelectric Material

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.

  11. Antireflection effects at nanostructured material interfaces and the suppression of thin-film interference

    NASA Astrophysics Data System (ADS)

    Yang, Qiaoyin; Zhang, Xu A.; Bagal, Abhijeet; Guo, Wei; Chang, Chih-Hao

    2013-06-01

    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.

  12. 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

  13. Temperature-dependent thermal conductivity in silicon nanostructured materials studied by the Boltzmann transport equation

    NASA Astrophysics Data System (ADS)

    Romano, Giuseppe; Esfarjani, Keivan; Strubbe, David A.; Broido, David; Kolpak, Alexie M.

    2016-01-01

    Nanostructured materials exhibit low thermal conductivity because of the additional scattering due to phonon-boundary interactions. As these interactions are highly sensitive to the mean free path (MFP) of phonons, MFP distributions in nanostructures can be dramatically distorted relative to bulk. Here we calculate the MFP distribution in periodic nanoporous Si for different temperatures, using the recently developed MFP-dependent Boltzmann transport equation. After analyzing the relative contribution of each phonon branch to thermal transport in nanoporous Si, we find that at room temperature optical phonons contribute 17 % to heat transport, compared to 5 % in bulk Si. Interestingly, we observe a constant thermal conductivity over the range 200 K nanostructured materials and demonstrate the necessity of multiscale heat transport engineering, in which the bulk material and geometry are optimized concurrently.

  14. Nanostructured solar irradiation control materials for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Kang, Jin Ho; Marshall, Iseley A.; Torrico, Mattew N.; Taylor, Chase R.; Ely, Jeffry; Henderson, Angel; Sauti, Godfrey; Gibbons, Luke J.; Kim, Jae-Woo; Park, Cheol; Lowther, Sharon E.; Lillehei, Peter T.; Bryant, Robert G.

    2012-10-01

    Tailoring the solar absorptivity (αs) and thermal emissivity (ɛT) 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 αs and ɛT 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 αs and μT 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.

  15. Structure-Interaction Effects In Novel Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Le, Nam B.

    Recent advances in experimental and computational methods have opened up new directions in graphene fundamental studies. In addition to understanding the basic properties of this material and its quasi-one dimensional structures, significant efforts are devoted to describing their long ranged dispersive interactions. Other two-dimensional materials, such as silicene, germanene, and transition metal dichalcogenides, are also being investigated aiming at finding complementary to graphene systems with other "wonder" properties. The focus of this work is to utilize first principles simulations methods to build our basic knowledge of structure-interaction relations in two-dimensional materials and design their properties. In particular, mechanical folding and extended defects in zigzag and armchair graphene nanoribbons can be used to modulate their electronic and spin polarization characteristics and achieve different stacking patterns. Our simulations concerning zigzag silicene nanoribbons show width-dependent antiferromagnetic-ferromagnetic transitions unlike the case of zigzag graphene nanoribbons, which are always antiferromagnetic. Heterostructures, build by stacking graphene, silicene, and MoS2, are also investigated. It is found that hybridization alters the electronic properties of the individual layers and new flexural and breathing phonon modes display unique behaviors in the heterostructure compositions. Anchored to SiC substrate graphene nanoribbons are also proposed as possible systems to be used in graphene electronics. Our findings are of importance not only for fundamental science, but they could also be used for future experimental developments.

  16. 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.

  17. Conversion of cellulose materials into nanostructured ceramics by biomineralization

    SciTech Connect

    Shin, Yongsoon; Exarhos, Gregory J

    2007-06-01

    Synthesis of hierarchically ordered silica materials having ordered wood cellular structures has been demonstrated through in-situ mineralization of wood by means of surfactant-directed mineralization in solutions of different pH. At low pH, silicic acid penetrates the buried interfaces of the wood cellular structure without clogging the pores to subsequently “molecularly paint” the interfaces thereby forming a positive replica following calcinations. At high pH, the hydrolyzed silica rapidly condenses to fill the open cells and pits within the structure resulting in a negative replica of the structure. Surfactant-templated mineralization in acid solutions leads to the formation of micelles that hexagonally pack at the wood interfaces preserving structural integrity while integrating hexagonally ordered nanoporosity into the structure of the cell walls following thermal treatment in air. The carbothermal reduction of mineralized wood with silica at high temperature produces biomorphic silicon carbide (SiC) materials, which are typical aggregations of β-SiC nanoparticles. To understand the roles of each component (lignin, crystalline cellulose, amorphous cellulose) comprising the natural biotemplates in the transformation to SiC rods, three different cellulose precursors including unbleached and bleached pulp, and cellulose nanocrystals have been utilized. Lignin in unbleached pulp blocked homogeneous penetration of silica into the pores between cellulose fibers resulting in non-uniform SiC fibers containing thick silica layers. Bleached pulp produced uniform SiC rods with camelback structures (80nm in diameter; ~50m in length), indicating that more silica infiltrates into the amorphous constituent of cellulose to form chunky rather than straight rod structures. The cellulose nanocrystal (CNXL) material produced clean and uniform SiC nanowires (70nm in diameter; >100m in length) without the camelback structure.

  18. Methods for high volume production of nanostructured materials

    DOEpatents

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

    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.

  19. High-resolution analytical TEM of nanostructured materials.

    PubMed

    Schneider, R

    2002-10-01

    This paper briefly reviews the potential applicability of analytical transmission electron microscopy (TEM) to elucidate both structural and chemical peculiarities of materials at high lateral resolution. Examples of analytical TEM investigations performed by energy-dispersive X-ray spectroscopy (EDXS), electron energy loss spectroscopy (EELS), and energy-filtered TEM (EFTEM) are presented for different materials systems including metals, ceramics, and compound semiconductors. In particular, results are given of imaging the element distribution in the interface region between gamma matrix and gamma' precipitate in the nickel-based superalloy SC16 by energy-filtered TEM. For core-shell structured BaTiO(3) particles the chemical composition and even the chemical bonding were revealed by EELS at a resolution of about 1 nm. A sub-nanometer resolution is demonstrated by energy-selective images of the Ga distribution in the surrounding of (In,Ga)As quantum dots. Moreover, the element distribution in (Al,Ga)As/AlAs multilayers with linear concentration gradients in a range of about 10 nm was investigated by EDXS line-profile analyses and EFTEM. PMID:12397484

  20. High-resolution analytical TEM of nanostructured materials.

    PubMed

    Schneider, R

    2002-10-01

    This paper briefly reviews the potential applicability of analytical transmission electron microscopy (TEM) to elucidate both structural and chemical peculiarities of materials at high lateral resolution. Examples of analytical TEM investigations performed by energy-dispersive X-ray spectroscopy (EDXS), electron energy loss spectroscopy (EELS), and energy-filtered TEM (EFTEM) are presented for different materials systems including metals, ceramics, and compound semiconductors. In particular, results are given of imaging the element distribution in the interface region between gamma matrix and gamma' precipitate in the nickel-based superalloy SC16 by energy-filtered TEM. For core-shell structured BaTiO(3) particles the chemical composition and even the chemical bonding were revealed by EELS at a resolution of about 1 nm. A sub-nanometer resolution is demonstrated by energy-selective images of the Ga distribution in the surrounding of (In,Ga)As quantum dots. Moreover, the element distribution in (Al,Ga)As/AlAs multilayers with linear concentration gradients in a range of about 10 nm was investigated by EDXS line-profile analyses and EFTEM.

  1. 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.

  2. 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.

  3. Nanostructured inorganic materials: Synthesis and associated electrochemical properties

    NASA Astrophysics Data System (ADS)

    Yau, Shali Zhu

    Synthetic strategy for preparing potential battery materials at low temperature was developed. Magnetite (Fe3O4), silver hollandnite (AgxMn8O16), magnesium manganese oxide (MgxMnO 2˙yH2O), and silver vanadium phosphorous oxide (Ag 2VO2PO4) were studied. Magnetite (Fe3O4) was prepared by coprecipitation induced by triethylamine from aqueous iron(II) and iron(III) chloride solutions of varying concentrations. Variation of the iron(II) and iron(III) concentrations results in crystallite size control of the Fe3O4 products. Materials characterization of the Fe3O4 samples is reported, including Brunauer-Emmitt-Teller (BET) surface area, x-ray powder diffraction (XRD), transmission electron microscopy (TEM), particle size, and saturation magnetization results. A strong correlation between discharge capacity and voltage recovery behavior versus crystallite size was observed when tested as an electrode material in lithium electrochemical cells. Silver hollandite (AgxMn8O16) was successfully synthesized through a low temperature reflux reaction. The crystallite size and silver content of AgxMn8O16 by varying the reactant ratio of silver permanganate (AgMnO4) and manganese sulfate monohydrate (MnSO4˙H2O). Silver hollandite was characterized by Brunauer-Emmitt-Teller (BET) surface area, inductively coupled plasma-optical emission (ICP-OES) spectrometry, helium pycnometry, simultaneous thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and x-ray powder diffraction (XRD). The crystallite size showed a strong correlation with silver content, BET surface area, and particle sizes. The silver hollandite cathode showed good discharge capacity retention in 30 cycles of discharge-charge. There were a good relationship between crystallite size and rate capability and pulse ability. Magnesium manganese oxide (MgxMnO2˙yH 2O) was made by redox reaction by mixing sodium hydroxide (NaOH), manganese sulfate monohydrate (MnSO4˙HO2), and potassium persulfate (K2S2O8

  4. Structural and functional engineering of one-dimensional nanostructures for device applications

    NASA Astrophysics Data System (ADS)

    Singh, Krishna Veer

    Fabrication of 1-D nanostructures has been an area of keen interest due to their application in nanodevices. Carbon nanotubes (CNTs) and semiconducting nanorods are 1-D nanostructures of great importance. There are various challenges related to structural and functional aspects of these materials, which need to be addressed for their adaptation in devices. To this end, two approaches have been developed: (1) structural engineering of the nanorods and (2) functionalization of CNTs for device applications. In first approach, a new technique to produce single crystal semiconducting nanorods was developed. Single crystalline structure of nanorods is essential to obtain reproducible performance. The novel synthesis technique 'template assisted sonoelectrochemical deposition' was utilized to develop 'copper sulfide' and 'copper indium sulfide' nanorods. The use of sonoelectrochemical method resulted in the best deposition rate as compared to stirring-assisted and regular electrochemical deposition, respectively. Observed increase in the bulk electrolyte temperature, high acoustic pressure and shock waves generated from the collapse of bubbles could explain improved mass transport and reaction rate, which results in the formation of single crystal nanorods. Nanorods in the range of 50-200nm in diameter were synthesized and electrically characterized as p-type semiconductors. Excellent structural and repeatable electrical properties of the various nanorods developed by this technique make it suitable for developing nanorods for device applications. In addition, detailed statistical analysis of the polycarbonate templates (50-200 nm nominal pore size) used in electrodeposition provided a better understanding of template's as well as nanorods' structure. In the second approach, we functionally engineered single walled carbon nanotubes (SWNTs) with peptide nucleic acid (PNA) to form functional conjugates for molecular electronics. SWNT-PNA-SWNT conjugates were synthesized

  5. 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

  6. 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.

  7. Nanostructured carbon materials for adsorption of methane and other gases

    SciTech Connect

    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.

  8. Physical Delivery of Macromolecules using High-Aspect Ratio Nanostructured Materials.

    PubMed

    Lee, Kunwoo; Lingampalli, Nithya; Pisano, Albert P; Murthy, Niren; So, Hongyun

    2015-10-28

    There is great need for the development of an efficient delivery method of macromolecules, including nucleic acids, proteins, and peptides, to cell cytoplasm without eliciting toxicity or changing cell behavior. High-aspect ratio nanomaterials have addressed many challenges present in conventional methods, such as cell membrane passage and endosomal degradation, and have shown the feasibility of efficient high-throughput macromolecule delivery with minimal perturbation of cells. This review describes the recent advances of in vitro and in vivo physical macromolecule delivery with high-aspect ratio nanostructured materials and summarizes the synthesis methods, material properties, relevant applications, and various potential directions.

  9. 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

  10. Laser microprocessing and nanoengineering of large-area functional micro/nanostructures

    NASA Astrophysics Data System (ADS)

    Tang, M.; Xie, X. Z.; Yang, J.; Chen, Z. C.; Xu, L.; Choo, Y. S.; Hong, M. H.

    2011-12-01

    Laser microprocessing and nanoengineering are of great interest to both scientists and engineers, since the inspired properties of functional micro/nanostructures over large areas can lead to numerous unique applications. Currently laser processing systems combined with high speed automation ensure the focused laser beam to process various materials at a high throughput and a high accuracy over large working areas. UV lasers are widely used in both laser microprocessing and nanoengineering. However by improving the processing methods, green pulsed laser is capable of replacing UV lasers to make high aspect ratio micro-grooves on fragile and transparent sapphire substrates. Laser micro-texturing can also tune the wetting property of metal surfaces from hydrophilic to super-hydrophobic at a contact angle of 161° without chemical coating. Laser microlens array (MLA) can split a laser beam into multiple laser beams and reduce the laser spot size down to sub-microns. It can be applied to fabricate split ring resonator (SRR) meta-materials for THz sensing, surface plasmonic resonance (SPR) structures for NIR and molding tools for soft lithography. Furthermore, laser interference lithography combined with thermal annealing can obtain a large area of sub-50nm nano-dot clusters used for SPR applications.

  11. 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.

  12. Shock wave interactions with nano-structured materials: a molecular dynamics approach

    NASA Astrophysics Data System (ADS)

    Al-Qananwah, A. K.; Koplik, J.; Andreopoulos, Y.

    2013-02-01

    Porous materials have long been known to be effective in blast mitigation strategies. Nano-structured materials appear to have an even greater potential for blast mitigation because of their high surface-to-volume ratio, a geometric factor which substantially attenuates shock wave propagation. A molecular dynamics approach was used to explore the effects of this remarkable property on the behavior of traveling shocks impacting on solid materials. The computational setup included a moving piston, a gas region, and a target solid wall with and without a porous structure. The materials involved were represented by realistic interaction potentials. The results indicate that the presence of a nano-porous material layer in front of the target wall reduced the stress magnitude and the energy deposited inside the solid by about 30 %, while at the same time substantially decreasing the loading rate.

  13. 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.

  14. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials

    NASA Astrophysics Data System (ADS)

    Kamarulzaman, Norlida; Kasim, Muhd Firdaus; Rusdi, Roshidah

    2015-08-01

    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.

  15. 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.

  16. 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.

  17. 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

  18. Molecular Design of Bioinspired Nanostructures for Biomedical Applications: Synthesis, Self-Assembly and Functional Properties

    NASA Astrophysics Data System (ADS)

    Xu, Hesheng Victor; Zheng, Xin Ting; Mok, Beverly Yin Leng; Ibrahim, Salwa Ali; Yu, Yong; Tan, Yen Nee

    2016-08-01

    Biomolecules are the nanoscale building blocks of cells, which play multifaceted roles in the critical biological processes such as biomineralization in a living organism. In these processes, the biological molecules such as protein and nucleic acids use their exclusive biorecognition properties enabled from their unique chemical composition, shape and function to initiate a cascade of cellular events. The exceptional features of these biomolecules, coupled with the recent advancement in nanotechnology, have led to the emergence of a new research field that focuses on the molecular design of bioinspired nanostructures that inherit the extraordinary function of natural biomaterials. These “bioinspired” nanostructures could be formulated by biomimetic approaches through either self-assembling of biomolecules or acting as a biomolecular template/precursor to direct the synthesis of nanocomposite. In either situation, the resulting nanomaterials exhibit phenomenal biocompatibility, superb aqueous solubility and excellent colloidal stability, branding them exceptionally desirable for both in vitro and in vivo biomedical applications. In this review, we will present the recent developments in the preparation of “bioinspired” nanostructures through biomimetic self-assembly and biotemplating synthesis, as well as highlight their functional properties and potential applications in biomedical diagnostics and therapeutic delivery. Lastly, we will conclude this topic with some personal perspective on the challenges and future outlooks of the “bioinspired” nanostructures for nanomedicine.

  19. 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.

  20. Facile size-tunable fabrication of functional tin dioxide nanostructures by multiple size reduction lithography.

    PubMed

    Park, Hyeong-Ho; Law, Wai Lung; Zhang, Xin; Hwang, Seon-Yong; Jung, Sang Hyun; Shin, Hyun-Beom; Kang, Ho Kwan; Park, Hyung-Ho; Hill, Ross H; Ko, Chul Ki

    2012-05-01

    A novel ultraviolet (UV)-assisted imprinting procedure that employs photosensitive tin(II) 2-ethylhexanoate is presented for the facile size-tunable fabrication of functional tin dioxide (SnO(2)) nanostructures by varying annealing temperatures. These imprinted SnO(2) nanostructures were also used as new masters for size reduction lithography. SnO(2) lines down to 40 nm wide were obtained from a silicon master with 200 nm wide lines by simply performing size reduction lithography twice. This leads to 80 and 87.5% reduction in the width and height of imprinted lines, respectively. An imprinted pattern annealed at 400 °C demonstrated transmittance greater than 90% over the range of 350-700 nm, which is high enough to make the pattern useful as a transparent SnO(2) mold. This demonstrated approach allows the accessibility to size-tunable molds, eliminating the need for conventional expensive imprinting masters with very fine structures, as well as functional SnO(2) nanostructures, potentially useful in applications where ordered surface nanostructures are required, such as photonic crystals, biological sensors, and model catalysts.

  1. Structural and Functional Hierarchy in Photosynthetic Energy Conversion-from Molecules to Nanostructures.

    PubMed

    Szabó, Tibor; Magyar, Melinda; Hajdu, Kata; Dorogi, Márta; Nyerki, Emil; Tóth, Tünde; Lingvay, Mónika; Garab, Győző; Hernádi, Klára; Nagy, László

    2015-12-01

    Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P(+)(QAQB)(-) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an

  2. Structural and Functional Hierarchy in Photosynthetic Energy Conversion—from Molecules to Nanostructures

    NASA Astrophysics Data System (ADS)

    Szabó, Tibor; Magyar, Melinda; Hajdu, Kata; Dorogi, Márta; Nyerki, Emil; Tóth, Tünde; Lingvay, Mónika; Garab, Győző; Hernádi, Klára; Nagy, László

    2015-12-01

    Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P+(QAQB)- charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an

  3. Deformational methods of material nanostructuring: Premises, history, state of the art, and prospects

    NASA Astrophysics Data System (ADS)

    Mulyukov, R. R.; Nazarov, A. A.; Imaev, R. M.

    2008-05-01

    Brief history of origin and development of methods of deformational nanostructuring of materials (DNM) also referred to as methods of severe plastic deformation (SPD) are presented. Principles and efficiencies of the most widespread DNM methods — torsion under quasi-hydrostatic pressure (THP), equal channel angular pressing (ECAP), and hydrostatic isothermal forging (HIF) — are analyzed. Results of pioneer research of the structure and properties of nanomaterials produced by these methods are given. Prospects for the DNM application in industrial technologies of metal treatment and product manufacturing are indicated.

  4. Electrospray neutralization process and apparatus for generation of nano-aerosol and nano-structured materials

    DOEpatents

    Bailey, Charles L.; Morozov, Victor; Vsevolodov, Nikolai N.

    2010-08-17

    The claimed invention describes methods and apparatuses for manufacturing nano-aerosols and nano-structured materials based on the neutralization of charged electrosprayed products with oppositely charged electrosprayed products. Electrosprayed products include molecular ions, nano-clusters and nano-fibers. Nano-aerosols can be generated when neutralization occurs in the gas phase. Neutralization of electrospan nano-fibers with molecular ions and charged nano-clusters may result in the formation of fibrous aerosols or free nano-mats. Nano-mats can also be produced on a suitable substrate, forming efficient nano-filters.

  5. Permittivity of dielectric composite materials comprising graphene nanoribbons. The effect of nanostructure.

    PubMed

    Dimiev, Ayrat; Zakhidov, Dante; Genorio, Bostjan; Oladimeji, Korede; Crowgey, Benjamin; Kempel, Leo; Rothwell, Edward J; Tour, James M

    2013-08-14

    New lightweight, flexible dielectric composite materials were fabricated by the incorporation of several new carbon nanostructures into a dielectric host matrix. Both the permittivity and loss tangent values of the resulting composites were widely altered by varying the type and content of the conductive filler. The dielectric constant was tuned from moderate to very high values, while the corresponding loss tangent changed from ultralow to extremely high. The data exemplify that nanoscale changes in the structure of the conductive filler result in dramatic changes in the dielectric properties of composites. A microcapacitor model most explains the behavior of the dielectric composites.

  6. Laser interference lithography for large area patterning and the fabrication of functional nanostructures

    NASA Astrophysics Data System (ADS)

    Wathuthanthri, Ishan

    Nature-inspired phenomena such as the "moth eye" and "lotus leaf" effects have gained a lot of interest in recent years due to potential applications in a wide range of scientific and engineering disciplines. To practically achieve a majority of these biomimetic applications it is necessary to fabricate such nano-featured surfaces in a low-cost and high-throughput manner. To this end, this dissertation focuses on developing and using the Interference Lithography (IL) technologies to achieve large-area nanopatterning. IL is a parallel-type nanolithography technique that shares many of the advantages of other parallel-type techniques such as deep-UV photolithography while alleviating a majority of concerns such as cost and complexity. IL relies on the interference of two or more beams of light where the resulting interference fringes are generally recorded on a light sensitive polymeric material such as photoresist. In simple two-beam IL systems, the periodicity of the interference fringes is simply a function of wavelength and the angle of separation of the two beams, while the maximum coverage area is a constrained by the optical path and the exposed area. To this extent, in the design of interferometers for nanopatterning, the challenge remains in designing systems where a simple mechanism exists for varying the angle of separation of the interfering beams and in turn periodicity of the interference fringes while also enabling large-area exposures. To this end, the first half of this dissertation demonstrates three different IL systems (Lloyd-mirror, two-degree-of freedom Lloyd-mirror, and the tunable two-mirror systems) designed and established at Stevens capable of fast tuning of periodicities while also achieving wafer-scale (4") large-area nanopatterning. Using the large-area nanopatterns of photoresist, various pattern transfer techniques have also been investigated where the photoresist film is used as a template layer to transfer the large-area periodic

  7. Application of Traditional and Nanostructure Materials for Medical Electron Beams Collimation: Numerical Simulation

    NASA Astrophysics Data System (ADS)

    Miloichikova, I. A.; Stuchebrov, S. G.; Zhaksybayeva, G. K.; Wagner, A. R.

    2015-11-01

    Nowadays, the commercial application of the electron accelerators grows in the industry, in the research investigations, in the medical diagnosis and treatment. In this regard, the electron beam profile modification in accordance with specific purposes is an actual task. In this paper the model of the TPU microtron extracted electron beam developed in the program “Computer Laboratory (PCLab)” is described. The internal beam divergence influence for the electron beam profile and depth dose distribution in the air is considered. The possibility of using the nanostructure materials for the electron beam formation was analyzed. The simulation data of the electron beam shape collimated by different materials (lead, corund- zirconia nanoceramic, gypsum) are shown. The collimator material influence for the electron beam profile and shape are analyzed.

  8. Nanodentistry: combining nanostructured materials and stem cells for dental tissue regeneration.

    PubMed

    Mitsiadis, Thimios A; Woloszyk, Anna; Jiménez-Rojo, Lucia

    2012-11-01

    Regenerative dentistry represents an attractive multidisciplinary therapeutic approach that complements traditional restorative/surgery techniques and benefits from recent advances in stem cell biology, molecular biology, genomics and proteomics. Materials science is important in such advances to move regenerative dentistry from the laboratory to the clinic. The design of novel nanostructured materials, such as biomimetic matrices and scaffolds for controlling cell fate and differentiation, and nanoparticles for diagnostics, imaging and targeted treatment, is needed. The combination of nanotechnology, which allows the creation of sophisticated materials with exquisite fine structural detail, and stem cell biology turns out to be increasingly useful in regenerative medicine. The administration to patients of dynamic biological agents comprising stem cells, bioactive scaffolds and/or nanoparticles will certainly increase the regenerative impact of dental pathological tissues. This overview briefly describes some of the actual benefits and future possibilities of nanomaterials in the emerging field of stem cell-based regenerative dentistry.

  9. Pattern recognition of monocyte chemoattractant protein-1 (MCP-1) in whole blood samples using new platforms based on nanostructured materials.

    PubMed

    Stefan-van Staden, Raluca-Ioana; Gugoasa, Livia Alexandra; Biris, Alexandru Radu

    2015-09-28

    Four stochastic microsensors based on nanostructured materials (graphene, maltodextrin (MD), and diamond) integrated in miniaturized platforms were proposed. Monocyte chemoattractant protein-1 (MCP-1) is a pro-inflammatory cytokine whose main function is to regulate cell trafficking. It is correlated with the incidence of cardiovascular diseases and obesity, and was used as the model analyte in this study. The screening of whole blood samples for MCP-1 can be done for concentrations ranging from 10(-12) to 10(-8) g mL(-1). The method was used for both qualitative and quantitative assessments of MCP-1 in whole blood samples. The lowest quantification limits for the assay of MCP-1 (1 pg mL(-1)) were reached when the microsensors based on protoporphyrin IX/Graphene-Au-3 and on MD/Graphene were employed in the platform design. PMID:26183340

  10. Pattern recognition of monocyte chemoattractant protein-1 (MCP-1) in whole blood samples using new platforms based on nanostructured materials

    NASA Astrophysics Data System (ADS)

    Stefan-van Staden, Raluca-Ioana; Gugoasa, Livia Alexandra; Biris, Alexandru Radu

    2015-09-01

    Four stochastic microsensors based on nanostructured materials (graphene, maltodextrin (MD), and diamond) integrated in miniaturized platforms were proposed. Monocyte chemoattractant protein-1 (MCP-1) is a pro-inflammatory cytokine whose main function is to regulate cell trafficking. It is correlated with the incidence of cardiovascular diseases and obesity, and was used as the model analyte in this study. The screening of whole blood samples for MCP-1 can be done for concentrations ranging from 10-12 to 10-8 g mL-1. The method was used for both qualitative and quantitative assessments of MCP-1 in whole blood samples. The lowest quantification limits for the assay of MCP-1 (1 pg mL-1) were reached when the microsensors based on protoporphyrin IX/Graphene-Au-3 and on MD/Graphene were employed in the platform design.

  11. WTEC Panel Report on Internaitonal Assessment of Research and Development in Catalysis by Nanostructured Materials

    SciTech Connect

    Davis, Robert J.; Guilants, Vadim V.; Huber, George; Lobo, Raul F.; Neurock, Matthew; Miller, Jeffrey T.; Sharma, Renu; Thompson, Levi

    2009-01-01

    This WTEC panel report assesses the international research and development activities in the field of catalysis by nanostructured materials. Catalysis is important for a wide variety of processes that impact manufacturing, energy conversion, and environmental protection. This study focused specifically on solid catalysts and how nanoscale structures associated with them affect their reactivity. The principal technical areas of the study are (a) design and control of synthetic nanostructures; (b) nanoscale characterization of catalysts in their working state; (c) theory and simulation; and (d) applications. The panel visited over 40 institutions and companies throughout East Asia and Western Europe to explore the active research projects in those institutions, the physical infrastructure used for the projects, the funding schemes that enable the research, and the collaborative interactions among universities, national laboratories, and corporate research centers. A bibliometric analysis of research in catalysis by nanostructured materials published from 1996 to 2005 was conducted as part of this WTEC study. The total number of published papers as well as the expected total number of citations of those papers revealed a growing focus on this subject. Western Europe was the numerical output leader in the world; U.S. output, while published in high-impact journals, was relatively stagnant, and the number of published papers originating from China was growing exponentially and expected to exceed that from the United States in the latter half of this decade. China's rapidly expanding economy together with its growth in large-scale chemical and refining plants motivate its significant commitment to catalysis research. The panel found that cooperation between universities and companies in catalysis R&D is common in Europe and Asia, presumably because of a more favorable intellectual property environment outside of the United States. In the area of catalyst synthesis, there

  12. 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). PMID:20815347

  13. Nanostructured hybrid layered-spinel cathode material synthesized by hydrothermal method for lithium-ion batteries.

    PubMed

    Liu, Cong; Wang, Zhiyuan; Shi, Chunsheng; Liu, Enzuo; He, Chunnian; Zhao, Naiqin

    2014-06-11

    Nanostructured spinel LiMn1.5Ni0.5O4, layered Li1.5Mn0.75Ni0.25O2.5 and layered-spinel hybrid particles have been successfully synthesized by hydrothermal methods. It is found that the nanostructured hybrid cathode contains both spinel and layered components, which could be expressed as Li1.13Mn0.75Ni0.25O2.32. Diffraction-contrast bright-field (BF) and dark-field (DF) images illustrate that the hybrid cathode has well dispersed spinel component. Electrochemical measurements reveal that the first-cycle efficiency of the layered-spinel hybrid cathode is greatly improved (up to 90%) compared with that of the layered material (71%) by integrating spinel component. Our investigation demonstrates that the spinel containing hybrid material delivers a high capacity of 240 mAh g(-1) with good cycling stability between 2.0 and 4.8 V at a current rate of 0.1 C.

  14. INVITED PAPER: Fundamentals of envelope function theory for electronic states and photonic modes in nanostructures

    NASA Astrophysics Data System (ADS)

    Burt, M. G.

    1999-03-01

    The increasing sophistication used in the fabrication of semiconductor nanostructures and in the experiments performed on them requires more sophisticated theoretical techniques than previously employed. The philosophy behind the author's exact envelope function representation method is clarified and contrasted with that of the conventional method. The significance of globally slowly varying envelope functions is explained. The difference between the envelope functions that appear in the author's envelope function representation and conventional envelope functions is highlighted and some erroneous statements made in the literature on the scope of envelope function methods are corrected. A perceived conflict between the standard effective mass Hamiltonian and the uncertainty principle is resolved demonstrating the limited usefulness of this principle in determining effective Hamiltonians. A simple example showing how to obtain correct operator ordering in electronic valence band Hamiltonians is worked out in detailed tutorial style. It is shown how the use of out of zone solutions to the author's approximate envelope function equations plays an essential role in their mathematically rigorous solution. In particular, a demonstration is given of the calculation of an approximate wavefunction for an electronic state in a one dimensional nanostructure with abrupt interfaces and disparate crystals using out of zone solutions alone. The author's work on the interband dipole matrix element for slowly varying envelope functions is extended to envelope functions without restriction. Exact envelope function equations are derived for multicomponent fields to emphasize that the author's method is a general one for converting a microscopic description to a mesoscopic one, applicable to linear partial differential equations with piecewise or approximately piecewise periodic coefficients. As an example, the method is applied to the derivation of approximate envelope function

  15. 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

  16. Electrical, thermal, catalytic and magnetic properties of nano-structured materials and their applications

    NASA Astrophysics Data System (ADS)

    Liu, Zuwei

    Nanotechnology is a subject that studies the fabrication, properties, and applications of materials on the nanometer-scale. Top-down and bottom-up approaches are commonly used in nano-structure fabrication. The top-down approach is used to fabricate nano-structures from bulk materials by lithography, etching, and polishing etc. It is commonly used in mechanical, electronic, and photonic devices. Bottom-up approaches fabricate nano-structures from atoms or molecules by chemical synthesis, self-assembly, and deposition, such as sol-gel processing, molecular beam epitaxy (MBE), focused ion beam (FIB) milling/deposition, chemical vapor deposition (CVD), and electro-deposition etc. Nano-structures can have several different dimensionalities, including zero-dimensional nano-structures, such as fullerenes, nano-particles, quantum dots, nano-sized clusters; one-dimensional nano-structures, such as carbon nanotubes, metallic and semiconducting nanowires; two-dimensional nano-structures, such as graphene, super lattice, thin films; and three-dimensional nano-structures, such as photonic structures, anodic aluminum oxide, and molecular sieves. These nano-structured materials exhibit unique electrical, thermal, optical, mechanical, chemical, and magnetic properties in the quantum mechanical regime. Various techniques can be used to study these properties, such as scanning probe microscopy (SPM), scanning/transmission electron microscopy (SEM/TEM), micro Raman spectroscopy, etc. These unique properties have important applications in modern technologies, such as random access memories, display, solar energy conversion, chemical sensing, and bio-medical devices. This thesis includes four main topics in the broad area of nanoscience: magnetic properties of ferro-magnetic cobalt nanowires, plasmonic properties of metallic nano-particles, photocatalytic properties of titanium dioxide nanotubes, and electro-thermal-optical properties of carbon nanotubes. These materials and their

  17. Center for Fundamental and Applied Research in Nanostructured and Lightweight Materials. Final Technical Summary

    SciTech Connect

    Mullins, Michael; Rogers, Tony; King, Julia; Keith, Jason; Cornilsen, Bahne; Allen, Jeffrey; Gilbert, Ryan; Holles, Joseph

    2010-09-28

    The core projects for this DOE-sponsored Center at Michigan Tech have focused on several of the materials problems identified by the NAS. These include: new electrode materials, enhanced PEM materials, lighter and more effective bipolar plates, and improvement of the carbon used as a current carrier. This project involved fundamental and applied research in the development and testing of lightweight and nanostructured materials to be used in fuel cell applications and for chemical synthesis. The advent of new classes of materials engineered at the nanometer level can produce materials that are lightweight and have unique physical and chemical properties. The grant was used to obtain and improve the equipment infrastructure to support this research and also served to fund seven research projects. These included: 1. Development of lightweight, thermally conductive bipolar plates for improved thermal management in fuel cells; 2. Exploration of pseudomorphic nanoscale overlayer bimetallic catalysts for fuel cells; 3. Development of hybrid inorganic/organic polymer nanocomposites with improved ionic and electronic properties; 4. Development of oriented polymeric materials for membrane applications; 5. Preparation of a graphitic carbon foam current collectors; 6. The development of lightweight carbon electrodes using graphitic carbon foams for battery and fuel cell applications; and 7. Movement of water in fuel cell electrodes.

  18. Ultra-strong and damage tolerant metallic bulk materials: A lesson from nanostructured pearlitic steel wires.

    PubMed

    Hohenwarter, A; Völker, B; Kapp, M W; Li, Y; Goto, S; Raabe, D; Pippan, R

    2016-09-14

    Structural materials used for safety critical applications require high strength and simultaneously high resistance against crack growth, referred to as damage tolerance. However, the two properties typically exclude each other and research efforts towards ever stronger materials are hampered by drastic loss of fracture resistance. Therefore, future development of novel ultra-strong bulk materials requires a fundamental understanding of the toughness determining mechanisms. As model material we use today's strongest metallic bulk material, namely, a nanostructured pearlitic steel wire, and measured the fracture toughness on micron-sized specimens in different crack growth directions and found an unexpected strong anisotropy in the fracture resistance. Along the wire axis the material reveals ultra-high strength combined with so far unprecedented damage tolerance. We attribute this excellent property combination to the anisotropy in the fracture toughness inducing a high propensity for micro-crack formation parallel to the wire axis. This effect causes a local crack tip stress relaxation and enables the high fracture toughness without being detrimental to the material's strength.

  19. Ultra-strong and damage tolerant metallic bulk materials: A lesson from nanostructured pearlitic steel wires.

    PubMed

    Hohenwarter, A; Völker, B; Kapp, M W; Li, Y; Goto, S; Raabe, D; Pippan, R

    2016-01-01

    Structural materials used for safety critical applications require high strength and simultaneously high resistance against crack growth, referred to as damage tolerance. However, the two properties typically exclude each other and research efforts towards ever stronger materials are hampered by drastic loss of fracture resistance. Therefore, future development of novel ultra-strong bulk materials requires a fundamental understanding of the toughness determining mechanisms. As model material we use today's strongest metallic bulk material, namely, a nanostructured pearlitic steel wire, and measured the fracture toughness on micron-sized specimens in different crack growth directions and found an unexpected strong anisotropy in the fracture resistance. Along the wire axis the material reveals ultra-high strength combined with so far unprecedented damage tolerance. We attribute this excellent property combination to the anisotropy in the fracture toughness inducing a high propensity for micro-crack formation parallel to the wire axis. This effect causes a local crack tip stress relaxation and enables the high fracture toughness without being detrimental to the material's strength. PMID:27624220

  20. Magnetic Alignment and Charge Transport Improvement in Functional Soft Materials

    NASA Astrophysics Data System (ADS)

    Majewski, Pawel W.

    The realization of nanostructured functional materials by self-assembly in polymers and polymer nanocomposites is adversely affected by persisting structural defects which greatly diminish the performance of the material. The use of magnetic fields to impose long-range order is investigated in three distinct systems - ion-conducting block copolymers, semiconducting nanowire-polymer composites and lyotropic surfactant mesophases. The alignment process is quantitatively studied with X-ray scattering and microscopic methods. Time and temperature resolved data collected in situ during the magnetic experiments provide an insight into the thermodynamic and kinetic aspects of the process. These data together with simultaneous electrical conductivity measurements allow relating fundamental structural properties (e.g., morphology and long-range order) to transport properties (i.e., conductivity). In particular, it is demonstrated that magnetic fields offer a viable route for improvement of electric conductivity in these systems. More than an order of magnitude increase in conductivity is recorded in magnetically-annealed materials. The resulting aligned nanostructured systems are attractive for ordered solid polymer electrolyte membranes, heterojunction photovoltaic devices and generally help to understand charge transport mechanisms in anisotropic heterogeneous systems.

  1. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology

    PubMed Central

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-01-01

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct “beyond graphene” domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346

  2. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    PubMed

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-01-01

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  3. Zero-dimensional nanostructured material with metallic bismuth nanoparticles: a new route for thermoelectrics

    NASA Astrophysics Data System (ADS)

    Benoit, Roland; Treguer, Mona; Saboungi, Marie-Louise

    2011-03-01

    The thermoelectric figure of merit ZT has so far not exceeded the value ZT=3 need to compete with mechanical energy conversion systems. However, theoretical work has shown that it is possible to reach values of ZT higher than this. One of the most promising routes is nanostructured materials, which offer the opportunity to tailor physical properties such as electrical and heat transport, due to the effects of electron filtering and phonon confinement. Dresselhaus et al. (ref.?) were among the first to show that 2D and 1D structures are capable of reaching ZT values higher than 2. The thermoelectric materials of current interest are in the form of nanotubes, nanodots and, more generally, superlattices composed of a matrix and nanoparticles. In our work we synthesize a periodic network of bismuth nanoparticles in a matrix of mesoporous Si O2 . We find that in this form bismuth transforms from a rhombohedral to a cubic structure, with improved filtering of electrons and phonons.

  4. Independent control of electrical and heat conduction by nanostructure designing for Si-based thermoelectric materials

    PubMed Central

    Yamasaka, Shuto; Watanabe, Kentaro; Sakane, Shunya; Takeuchi, Shotaro; Sakai, Akira; Sawano, Kentarou; Nakamura, Yoshiaki

    2016-01-01

    The high electrical and drastically-low thermal conductivities, a vital goal for high performance thermoelectric (TE) materials, are achieved in Si-based nanoarchitecture composed of Si channel layers and epitaxial Ge nanodots (NDs) with ultrahigh areal density (~1012 cm−2). In this nanoarchitecture, the ultrasmall NDs and Si channel layers play roles of phonon scattering sources and electrical conduction channels, respectively. Electron conductivity in n-type nanoacrhitecture shows high values comparable to those of epitaxial Si films despite the existence of epitaxial NDs. This is because Ge NDs mainly scattered not electrons but phonons selectively, which could be attributed to the small conduction band offset at the epitaxially-grown Si/Ge interface and high transmission probability through stacking faults. These results demonstrate an independent control of thermal and electrical conduction for phonon-glass electron-crystal TE materials by nanostructure designing and the energetic and structural interface control. PMID:26973092

  5. Independent control of electrical and heat conduction by nanostructure designing for Si-based thermoelectric materials.

    PubMed

    Yamasaka, Shuto; Watanabe, Kentaro; Sakane, Shunya; Takeuchi, Shotaro; Sakai, Akira; Sawano, Kentarou; Nakamura, Yoshiaki

    2016-01-01

    The high electrical and drastically-low thermal conductivities, a vital goal for high performance thermoelectric (TE) materials, are achieved in Si-based nanoarchitecture composed of Si channel layers and epitaxial Ge nanodots (NDs) with ultrahigh areal density (~10(12) cm(-2)). In this nanoarchitecture, the ultrasmall NDs and Si channel layers play roles of phonon scattering sources and electrical conduction channels, respectively. Electron conductivity in n-type nanoacrhitecture shows high values comparable to those of epitaxial Si films despite the existence of epitaxial NDs. This is because Ge NDs mainly scattered not electrons but phonons selectively, which could be attributed to the small conduction band offset at the epitaxially-grown Si/Ge interface and high transmission probability through stacking faults. These results demonstrate an independent control of thermal and electrical conduction for phonon-glass electron-crystal TE materials by nanostructure designing and the energetic and structural interface control. PMID:26973092

  6. Lyotropic liquid crystal engineering-ordered nanostructured small molecule amphiphile self-assembly materials by design.

    PubMed

    Fong, Celesta; Le, Tu; Drummond, Calum J

    2012-02-01

    Future nanoscale soft matter design will be guided to a large extent by the teachings of amphiphile (lipid or surfactant) self-assembly. Ordered nanostructured lyotropic liquid crystalline mesophases may form in select mixtures of amphiphile and solvent. To reproducibly engineer the low energy amphiphile self-assembly of materials for the future, we must first learn the design principles. In this critical review we discuss the evolution of these design rules and in particular discuss recent key findings regarding (i) what drives amphiphile self-assembly, (ii) what governs the self-assembly structures that are formed, and (iii) how can amphiphile self-assembly materials be used to enhance product formulations, including drug delivery vehicles, medical imaging contrast agents, and integral membrane protein crystallisation media. We focus upon the generation of 'dilutable' lyotropic liquid crystal phases with two- and three-dimensional geometries from amphiphilic small molecules (225 references).

  7. Functional materials for rechargeable batteries.

    PubMed

    Cheng, Fangyi; Liang, Jing; Tao, Zhanliang; Chen, Jun

    2011-04-19

    There is an ever-growing demand for rechargeable batteries with reversible and efficient electrochemical energy storage and conversion. Rechargeable batteries cover applications in many fields, which include portable electronic consumer devices, electric vehicles, and large-scale electricity storage in smart or intelligent grids. The performance of rechargeable batteries depends essentially on the thermodynamics and kinetics of the electrochemical reactions involved in the components (i.e., the anode, cathode, electrolyte, and separator) of the cells. During the past decade, extensive efforts have been dedicated to developing advanced batteries with large capacity, high energy and power density, high safety, long cycle life, fast response, and low cost. Here, recent progress in functional materials applied in the currently prevailing rechargeable lithium-ion, nickel-metal hydride, lead acid, vanadium redox flow, and sodium-sulfur batteries is reviewed. The focus is on research activities toward the ionic, atomic, or molecular diffusion and transport; electron transfer; surface/interface structure optimization; the regulation of the electrochemical reactions; and the key materials and devices for rechargeable batteries. PMID:21394791

  8. In situ X-ray pair distribution function analysis of geopolymer gel nanostructure formation kinetics.

    PubMed

    White, Claire E; Provis, John L; Bloomer, Breaunnah; Henson, Neil J; Page, Katharine

    2013-06-14

    With the ever-increasing environmentally-driven demand for technologically advanced structural materials, geopolymer cement is fast becoming a viable alternative to traditional cements due to its proven engineering characteristics and the reduction in CO2 emitted during manufacturing (as much as 80% less CO2 emitted in manufacture, compared to ordinary Portland cement). Nevertheless, much remains unknown regarding the kinetics of reaction responsible for nanostructural evolution during the geopolymerisation process. Here, in situ X-ray total scattering measurements and pair distribution function (PDF) analysis are used to quantify the extent of reaction as a function of time for alkali-activated metakaolin/slag geopolymer binders, including the impact of various activators (alkali hydroxide/silicate) on the kinetics of the geopolymerisation reaction. Quantifying the reaction process in situ from X-ray PDF data collected during the initial ten hours can provide an estimate of the total reaction extent, but when combined with data obtained at longer times (128 days here) enables more accurate determination of the overall rate of reaction. To further assess the initial stages of the geopolymerisation reaction process, a pseudo-single step first order rate equation is fitted to the extent of reaction data, which reveals important mechanistic information regarding the role of free silica in the activators in the evolution of the binder systems. Hence, it is shown that in situ X-ray PDF analysis is an ideal experimental local structure tool to probe the reaction kinetics of complex reacting systems involving transitions between disordered/amorphous phases, of which geopolymerisation is an important example.

  9. In situ X-ray pair distribution function analysis of geopolymer gel nanostructure formation kinetics.

    PubMed

    White, Claire E; Provis, John L; Bloomer, Breaunnah; Henson, Neil J; Page, Katharine

    2013-06-14

    With the ever-increasing environmentally-driven demand for technologically advanced structural materials, geopolymer cement is fast becoming a viable alternative to traditional cements due to its proven engineering characteristics and the reduction in CO2 emitted during manufacturing (as much as 80% less CO2 emitted in manufacture, compared to ordinary Portland cement). Nevertheless, much remains unknown regarding the kinetics of reaction responsible for nanostructural evolution during the geopolymerisation process. Here, in situ X-ray total scattering measurements and pair distribution function (PDF) analysis are used to quantify the extent of reaction as a function of time for alkali-activated metakaolin/slag geopolymer binders, including the impact of various activators (alkali hydroxide/silicate) on the kinetics of the geopolymerisation reaction. Quantifying the reaction process in situ from X-ray PDF data collected during the initial ten hours can provide an estimate of the total reaction extent, but when combined with data obtained at longer times (128 days here) enables more accurate determination of the overall rate of reaction. To further assess the initial stages of the geopolymerisation reaction process, a pseudo-single step first order rate equation is fitted to the extent of reaction data, which reveals important mechanistic information regarding the role of free silica in the activators in the evolution of the binder systems. Hence, it is shown that in situ X-ray PDF analysis is an ideal experimental local structure tool to probe the reaction kinetics of complex reacting systems involving transitions between disordered/amorphous phases, of which geopolymerisation is an important example. PMID:23450172

  10. High-rate production of functional nanostructured films and devices by coupling flame spray pyrolysis with supersonic expansion.

    PubMed

    Wegner, K; Vinati, S; Piseri, P; Antonini, A; Zelioli, A; Barborini, E; Ducati, C; Milani, P

    2012-05-11

    The fabrication of functional thin films and devices by direct deposition of nanoparticles from the gas phase is a promising approach enabling, for instance, the integration of complex analytical and sensing capabilities on microfabricated platforms. Aerosol-based techniques ensure large-scale nanoparticle production and they are potentially suited for this goal. However, they are not adequate in terms of fine control over the lateral resolution of the coatings, mild processing conditions (avoiding high temperature and aggressive chemicals), low contamination and compatibility with microfabrication processes. Here we report the high-rate and efficient production of functional nanostructured films by nanoparticle assembling obtained by the combination of flame spray pyrolysis and supersonic expansion. Our approach merges the advantages of flame spray pyrolysis for bulk nanopowders such as process stability and wide material library availability with those of supersonic cluster beam deposition in terms of lateral resolution and of direct integration of nanomaterials on devices. We efficiently produced nanostructured films and devices (such as gas sensors) using metal oxide, pure noble metal and oxide-supported noble metal nanoparticles. PMID:22516767

  11. High-rate production of functional nanostructured films and devices by coupling flame spray pyrolysis with supersonic expansion.

    PubMed

    Wegner, K; Vinati, S; Piseri, P; Antonini, A; Zelioli, A; Barborini, E; Ducati, C; Milani, P

    2012-05-11

    The fabrication of functional thin films and devices by direct deposition of nanoparticles from the gas phase is a promising approach enabling, for instance, the integration of complex analytical and sensing capabilities on microfabricated platforms. Aerosol-based techniques ensure large-scale nanoparticle production and they are potentially suited for this goal. However, they are not adequate in terms of fine control over the lateral resolution of the coatings, mild processing conditions (avoiding high temperature and aggressive chemicals), low contamination and compatibility with microfabrication processes. Here we report the high-rate and efficient production of functional nanostructured films by nanoparticle assembling obtained by the combination of flame spray pyrolysis and supersonic expansion. Our approach merges the advantages of flame spray pyrolysis for bulk nanopowders such as process stability and wide material library availability with those of supersonic cluster beam deposition in terms of lateral resolution and of direct integration of nanomaterials on devices. We efficiently produced nanostructured films and devices (such as gas sensors) using metal oxide, pure noble metal and oxide-supported noble metal nanoparticles.

  12. Dual-functionalized nanostructured biointerfaces by click chemistry.

    PubMed

    Schenk, Franziska C; Boehm, Heike; Spatz, Joachim P; Wegner, Seraphine V

    2014-06-17

    The presentation of biologically active molecules at interfaces has made it possible to investigate the responses of cells to individual molecules in their matrix at a given density and spacing. However, more sophisticated methods are needed to create model surfaces that present more than one molecule in a controlled manner in order to mimic at least partially the complexity given in natural environments. Herein, we present dual-functionalized surfaces combining quasi-hexagonally arranged gold nanoparticles with defined spacings and a newly developed PEG-alkyne coating to functionalize the glass in the intermediate space. The PEG-alkyne coating provides an inert background for cell interactions but can be modified orthogonally to the gold nanoparticles with numerous azides, including spectroscopically active molecules, peptides, and biotin at controlled densities by the copper(I)-catalyzed azide alkyne click reaction. The simultaneous presentation of cRGD on the gold nanoparticles with 100 nm spacing and synergy peptide PHSRN in the space between has a striking effect on REF cell adhesion; cells adhere, spread, and form mature focal adhesions on the dual-functionalized surfaces, whereas cells cannot adhere on either monofunctional surface. Combining these orthogonal functionalization methods creates a new platform to study precisely the crosstalk and synergy between different signaling molecules and clustering effects in ligand-receptor interactions. PMID:24856250

  13. Dual-Functionalized Nanostructured Biointerfaces by Click Chemistry

    PubMed Central

    2014-01-01

    The presentation of biologically active molecules at interfaces has made it possible to investigate the responses of cells to individual molecules in their matrix at a given density and spacing. However, more sophisticated methods are needed to create model surfaces that present more than one molecule in a controlled manner in order to mimic at least partially the complexity given in natural environments. Herein, we present dual-functionalized surfaces combining quasi-hexagonally arranged gold nanoparticles with defined spacings and a newly developed PEG-alkyne coating to functionalize the glass in the intermediate space. The PEG-alkyne coating provides an inert background for cell interactions but can be modified orthogonally to the gold nanoparticles with numerous azides, including spectroscopically active molecules, peptides, and biotin at controlled densities by the copper(I)-catalyzed azide alkyne click reaction. The simultaneous presentation of cRGD on the gold nanoparticles with 100 nm spacing and synergy peptide PHSRN in the space between has a striking effect on REF cell adhesion; cells adhere, spread, and form mature focal adhesions on the dual-functionalized surfaces, whereas cells cannot adhere on either monofunctional surface. Combining these orthogonal functionalization methods creates a new platform to study precisely the crosstalk and synergy between different signaling molecules and clustering effects in ligand–receptor interactions. PMID:24856250

  14. Ultra-strong and damage tolerant metallic bulk materials: A lesson from nanostructured pearlitic steel wires

    NASA Astrophysics Data System (ADS)

    Hohenwarter, A.; Völker, B.; Kapp, M. W.; Li, Y.; Goto, S.; Raabe, D.; Pippan, R.

    2016-09-01

    Structural materials used for safety critical applications require high strength and simultaneously high resistance against crack growth, referred to as damage tolerance. However, the two properties typically exclude each other and research efforts towards ever stronger materials are hampered by drastic loss of fracture resistance. Therefore, future development of novel ultra-strong bulk materials requires a fundamental understanding of the toughness determining mechanisms. As model material we use today’s strongest metallic bulk material, namely, a nanostructured pearlitic steel wire, and measured the fracture toughness on micron-sized specimens in different crack growth directions and found an unexpected strong anisotropy in the fracture resistance. Along the wire axis the material reveals ultra-high strength combined with so far unprecedented damage tolerance. We attribute this excellent property combination to the anisotropy in the fracture toughness inducing a high propensity for micro-crack formation parallel to the wire axis. This effect causes a local crack tip stress relaxation and enables the high fracture toughness without being detrimental to the material’s strength.

  15. Ultra-strong and damage tolerant metallic bulk materials: A lesson from nanostructured pearlitic steel wires

    PubMed Central

    Hohenwarter, A.; Völker, B.; Kapp, M. W.; Li, Y.; Goto, S.; Raabe, D.; Pippan, R.

    2016-01-01

    Structural materials used for safety critical applications require high strength and simultaneously high resistance against crack growth, referred to as damage tolerance. However, the two properties typically exclude each other and research efforts towards ever stronger materials are hampered by drastic loss of fracture resistance. Therefore, future development of novel ultra-strong bulk materials requires a fundamental understanding of the toughness determining mechanisms. As model material we use today’s strongest metallic bulk material, namely, a nanostructured pearlitic steel wire, and measured the fracture toughness on micron-sized specimens in different crack growth directions and found an unexpected strong anisotropy in the fracture resistance. Along the wire axis the material reveals ultra-high strength combined with so far unprecedented damage tolerance. We attribute this excellent property combination to the anisotropy in the fracture toughness inducing a high propensity for micro-crack formation parallel to the wire axis. This effect causes a local crack tip stress relaxation and enables the high fracture toughness without being detrimental to the material’s strength. PMID:27624220

  16. Nanostructured pseudocapacitive materials decorated 3D graphene foam electrodes for next generation supercapacitors.

    PubMed

    Patil, Umakant; Lee, Su Chan; Kulkarni, Sachin; Sohn, Ji Soo; Nam, Min Sik; Han, Suhyun; Jun, Seong Chan

    2015-04-28

    Nowadays, advancement in performance of proficient multifarious electrode materials lies conclusively at the core of research concerning energy storage devices. To accomplish superior capacitance performance the requirements of high capacity, better cyclic stability and good rate capability can be expected from integration of electrochemical double layer capacitor based carbonaceous materials (high power density) and pseudocapacitive based metal hydroxides/oxides or conducting polymers (high energy density). The envisioned three dimensional (3D) graphene foams are predominantly advantageous to extend potential applicability by offering a large active surface area and a highly conductive continuous porous network for fast charge transfer with decoration of nanosized pseudocapacitive materials. In this article, we review the latest methodologies and performance evaluation for several 3D graphene based metal oxides/hydroxides and conducting polymer electrodes with improved electrochemical properties for next-generation supercapacitors. The most recent research advancements of our and other groups in the field of 3D graphene based electrode materials for supercapacitors are discussed. To assess the studied materials fully, a careful interpretation and rigorous scrutiny of their electrochemical characteristics is essential. Auspiciously, both nano-structuration as well as confinement of metal hydroxides/oxides and conducting polymers onto a conducting porous 3D graphene matrix play a great role in improving the performance of electrodes mainly due to: (i) active material access over large surface area with fast charge transportation; (ii) synergetic effect of electric double layer and pseudocapacitive based charge storing.

  17. Nanostructured pseudocapacitive materials decorated 3D graphene foam electrodes for next generation supercapacitors

    NASA Astrophysics Data System (ADS)

    Patil, Umakant; Lee, Su Chan; Kulkarni, Sachin; Sohn, Ji Soo; Nam, Min Sik; Han, Suhyun; Jun, Seong Chan

    2015-04-01

    Nowadays, advancement in performance of proficient multifarious electrode materials lies conclusively at the core of research concerning energy storage devices. To accomplish superior capacitance performance the requirements of high capacity, better cyclic stability and good rate capability can be expected from integration of electrochemical double layer capacitor based carbonaceous materials (high power density) and pseudocapacitive based metal hydroxides/oxides or conducting polymers (high energy density). The envisioned three dimensional (3D) graphene foams are predominantly advantageous to extend potential applicability by offering a large active surface area and a highly conductive continuous porous network for fast charge transfer with decoration of nanosized pseudocapacitive materials. In this article, we review the latest methodologies and performance evaluation for several 3D graphene based metal oxides/hydroxides and conducting polymer electrodes with improved electrochemical properties for next-generation supercapacitors. The most recent research advancements of our and other groups in the field of 3D graphene based electrode materials for supercapacitors are discussed. To assess the studied materials fully, a careful interpretation and rigorous scrutiny of their electrochemical characteristics is essential. Auspiciously, both nano-structuration as well as confinement of metal hydroxides/oxides and conducting polymers onto a conducting porous 3D graphene matrix play a great role in improving the performance of electrodes mainly due to: (i) active material access over large surface area with fast charge transportation; (ii) synergetic effect of electric double layer and pseudocapacitive based charge storing.

  18. Functional Nanostructured Platforms for Chemical and Biological Sensing

    SciTech Connect

    Letant, S E

    2006-03-20

    The central goal of our work is to combine semiconductor nanotechnology and surface functionalization in order to build platforms for the selective detection of bio-organisms ranging in size from bacteria (micron range) down to viruses, as well as for the detection of chemical agents (nanometer range). We will show on three porous silicon platforms how pore geometry and pore wall chemistry can be combined and optimized to capture and detect specific targets. We developed a synthetic route allowing to directly anchor proteins on silicon surfaces and illustrated the relevance of this technique by immobilizing live enzymes onto electrochemically etched luminescent nano-porous silicon. The powerful association of the specific enzymes with the transducing matrix led to a selective hybrid platform for chemical sensing. We also used light-assisted electrochemistry to produce periodic arrays of through pores on pre-patterned silicon membranes with controlled diameters ranging from many microns down to tens of nanometers. We demonstrated the first covalently functionalized silicon membranes and illustrated their selective capture abilities with antibody-coated micro-beads. These engineered membranes are extremely versatile and could be adapted to specifically recognize the external fingerprints (size and coat composition) of target bio-organisms. Finally, we fabricated locally functionalized single nanopores using a combination of focused ion beam drilling and ion beam assisted oxide deposition. We showed how a silicon oxide ring can be grown around a single nanopore and how it can be functionalized with DNA probes to detect single viral-sized beads. The next step for this platform is the detection of whole viruses and bacteria.

  19. Functional nanostructured platforms for chemical and biological sensing

    NASA Astrophysics Data System (ADS)

    Létant, S. E.

    2006-05-01

    The central goal of our work is to combine semiconductor nanotechnology and surface functionalization in order to build platforms for the selective detection of bio-organisms ranging in size from bacteria (micron range) down to viruses, as well as for the detection of chemical agents (nanometer range). We will show on three porous silicon platforms how pore geometry and pore wall chemistry can be combined and optimized to capture and detect specific targets. We developed a synthetic route allowing to directly anchor proteins on silicon surfaces and illustrated the relevance of this technique by immobilizing live enzymes onto electrochemically etched luminescent nano-porous silicon. The powerful association of the specific enzymes with the transducing matrix led to a selective hybrid platform for chemical sensing. We also used light-assisted electrochemistry to produce periodic arrays of through pores on pre-patterned silicon membranes with controlled diameters ranging from many microns down to tens of nanometers. We demonstrated the first covalently functionalized silicon membranes and illustrated their selective capture abilities with antibody-coated micro-beads. These engineered membranes are extremely versatile and could be adapted to specifically recognize the external fingerprints (size and coat composition) of target bio-organisms. Finally, we fabricated locally functionalized single nanopores using a combination of focused ion beam drilling and ion beam assisted oxide deposition. We showed how a silicon oxide ring can be grown around a single nanopore and how it can be functionalized with DNA probes to detect single viral-sized beads. The next step for this platform is the detection of whole viruses and bacteria.

  20. Nano-Structured Bio-Inorganic Hybrid Material for High Performing Oxygen Reduction Catalyst.

    PubMed

    Jiang, Rongzhong; Tran, Dat T; McClure, Joshua P; Chu, Deryn

    2015-08-26

    In this study, we demonstrate a non-Pt nanostructured bioinorganic hybrid (BIH) catalyst for catalytic oxygen reduction in alkaline media. This catalyst was synthesized through biomaterial hemin, nanostructured Ag-Co alloy, and graphene nano platelets (GNP) by heat-treatment and ultrasonically processing. This hybrid catalyst has the advantages of the combined features of these bio and inorganic materials. A 10-fold improvement in catalytic activity (at 0.8 V vs RHE) is achieved in comparison of pure Ag nanoparticles (20-40 nm). The hybrid catalyst reaches 80% activity (at 0.8 V vs RHE) of the state-of-the-art catalyst (containing 40% Pt and 60% active carbon). Comparable catalytic stability for the hybrid catalyst with the Pt catalyst is observed by chronoamperometric experiment. The hybrid catalyst catalyzes 4-electron oxygen reduction to produce water with fast kinetic rate. The rate constant obtained from the hybrid catalyst (at 0.6 V vs RHE) is 4 times higher than that of pure Ag/GNP catalyst. A catalytic model is proposed to explain the oxygen reduction reaction at the BIH catalyst. PMID:26280984

  1. Nano-Structured Bio-Inorganic Hybrid Material for High Performing Oxygen Reduction Catalyst.

    PubMed

    Jiang, Rongzhong; Tran, Dat T; McClure, Joshua P; Chu, Deryn

    2015-08-26

    In this study, we demonstrate a non-Pt nanostructured bioinorganic hybrid (BIH) catalyst for catalytic oxygen reduction in alkaline media. This catalyst was synthesized through biomaterial hemin, nanostructured Ag-Co alloy, and graphene nano platelets (GNP) by heat-treatment and ultrasonically processing. This hybrid catalyst has the advantages of the combined features of these bio and inorganic materials. A 10-fold improvement in catalytic activity (at 0.8 V vs RHE) is achieved in comparison of pure Ag nanoparticles (20-40 nm). The hybrid catalyst reaches 80% activity (at 0.8 V vs RHE) of the state-of-the-art catalyst (containing 40% Pt and 60% active carbon). Comparable catalytic stability for the hybrid catalyst with the Pt catalyst is observed by chronoamperometric experiment. The hybrid catalyst catalyzes 4-electron oxygen reduction to produce water with fast kinetic rate. The rate constant obtained from the hybrid catalyst (at 0.6 V vs RHE) is 4 times higher than that of pure Ag/GNP catalyst. A catalytic model is proposed to explain the oxygen reduction reaction at the BIH catalyst.

  2. 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

  3. Functional block copolymers for applications in advanced materials, energy storage, and lithography

    NASA Astrophysics Data System (ADS)

    Hardy, Christopher George

    Block copolymers spontaneously self-assembly into a wide variety of ordered nanostructures on the length scale of 5 - 100 nm due to the thermodynamic immiscibility between the covalently linked, chemically distinct polymer chains. Incorporating desirable functional groups into block copolymer systems can lead to confinement of the functional group to a specific domain upon microphase separation of the block copolymer. The resulting materials display desirable characteristics of the functional group in a well-ordered nanostructure. Such systems have been utilized in a wide variety of applications including catalysis, ceramic materials, and membranes. This dissertation is focused on the synthesis, characterization, self-assembly and materials processing of various functionalized block copolymer systems. An assortment of monomers functionalized with specific groups were prepared and polymerized by a variety of polymerization techniques including atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization, and ring-opening metathesis polymerization. Self-assembly of the functionalized block copolymers led to well defined nanostructures in bulk and thin films. Depending upon the functional group incorporated, the ordered materials were utilized in various applications including ordered catalysts, energy storage, and templates for nanolithography..

  4. Curvature-Induced Anomalous Enhancement in the Work Function of Nanostructures.

    PubMed

    Kaur, Jasmin; Kant, Rama

    2015-08-01

    An analytical theory to estimate the electronic work function in curved geometries is formulated under Thomas-Fermi approximation. The work function is framed as the work against the electrostatic self-capacitive energy. The contribution of surface curvature is characterized by mean and Gaussian curvature (through multiple scattering expansion). The variation in work function of metal and semimetal nanostructures is shown as the consequence of surface radius of curvature comparable to electronic screening length. For ellipsoidal particles, the maximum value of work function is observed at the equator and poles for oblate and prolate particles, respectively, whereas triaxial ellipsoid shows nonuniform distribution of the work function over the surface. Similarly, theory predicts manifold increase in the work function for a particle with atomic scale roughness. Finally, the theory is validated with experimental data, and it is concluded that the work function of a nanoparticle can be tailored through its shape. PMID:26267172

  5. Noncovalent functionalization of multiwalled carbon nanotubes: application in hybrid nanostructures.

    PubMed

    Wang, Tie; Hu, Xiaoge; Qu, Xiaohu; Dong, Shaojun

    2006-04-01

    We developed a reproducible, noncovalent strategy to functionalize multiwalled carbon nanotubes (MWNTs) via embedding nanotubes in polysiloxane shells. (3-Aminopropyl)triethoxysilane molecules adsorbed to the nanotube surfaces via hydrophobic interactions are polymerized simply by acid catalysis and form a thin polysiloxane layer. On the basis of the embedded MWNTs, negatively charged gold nanoparticles are anchored to the nanotube surfaces via electrostatic interactions between the protonated amino groups and the gold nanoparticles. Furthermore, these gold nanoparticles can further grow and magnify along the nanotubes through heating in HAuCl4 aqueous solution at 100 degrees C; as a result these nanoparticles are joined to form continuous gold nanowires with MWNTs acting as templates. PMID:16570965

  6. Peptide Self-Assembly for Crafting Functional Biological Materials

    PubMed Central

    Matson, John B.; Zha, R. Helen; Stupp, Samuel I.

    2011-01-01

    Self-assembling, peptide-based scaffolds are frontrunners in the search for biomaterials with widespread impact in regenerative medicine. The inherent biocompatibility and cell signaling capabilities of peptides, in combination with control of secondary structure, has led to the development of a broad range of functional materials with potential for many novel therapies. More recently, membranes formed through complexation of peptide nanostructures with natural biopolymers have led to the development of hierarchically-structured constructs with potentially far-reaching applications in biology and medicine. In this review, we highlight recent advances in peptide-based gels and membranes, including work from our group and others. Specifically, we discuss the application of peptide-based materials in the regeneration of bone and enamel, cartilage, and the central nervous system, as well as the transplantation of islets, wound-healing, cardiovascular therapies, and treatment of erectile dysfunction after prostatectomy PMID:22125413

  7. Plasma-based ion implantation: a valuable technology for the elaboration of innovative materials and nanostructured thin films

    NASA Astrophysics Data System (ADS)

    Vempaire, D.; Pelletier, J.; Lacoste, A.; Béchu, S.; Sirou, J.; Miraglia, S.; Fruchart, D.

    2005-05-01

    Plasma-based ion implantation (PBII), invented in 1987, can now be considered as a mature technology for thin film modification. After a brief recapitulation of the principle and physics of PBII, its advantages and disadvantages, as compared to conventional ion beam implantation, are listed and discussed. The elaboration of thin films and the modification of their functional properties by PBII have already been achieved in many fields, such as microelectronics (plasma doping/PLAD), biomaterials (surgical implants, bio- and blood-compatible materials), plastics (grafting, surface adhesion) and metallurgy (hard coatings, tribology), to name a few. The major advantages of PBII processing lie, on the one hand, in its flexibility in terms of ion implantation energy (from 0 to 100 keV) and operating conditions (plasma density, collisional or non-collisional ion sheath), and, on the other hand, in the easy transferrability of processes from the laboratory to industry. The possibility of modifying the composition and physical nature of the films, or of drastically changing their physical properties over several orders of magnitude makes this technology very attractive for the elaboration of innovative materials, including metastable materials, and the realization of micro- or nanostructures. A review of the state of the art in these domains is presented and illustrated through a few selected examples. The perspectives opened up by PBII processing, as well as its limitations, are discussed.

  8. Functionalization of Biomolecules with Nanostructured Porous Silicon for Biomedical Application

    NASA Astrophysics Data System (ADS)

    Jeyakumar, P.; Saravanakumar, S. S.; Kulathuraan, K.; Ramadas, V.; Natarajan, B.

    2015-02-01

    Porous silicon (PS) fabrication, changes in the optical properties and surface modification in the oxidized PS (dipped into the Glucose oxide) due to the infiltration of biomolecules using Luminescence Spectrophotometer [Photoluminescence (PL)], Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM) were studied. The surface morphology of oxidized PS (OPS) and treated with Glucose have been studied by SEM. Spontaneous imbibition weight was calculated theoretically using imbibition equation for the porous medium using glucose solution as the wetting liquid. FTIR analysis revealed that, the strong Si-H, Si-O-Si bonds which covered most of the OPS surface. In the glucose treated PS layer, the amide I (C=O) stretch and amide II (C=N) stretch (1690 cm-1 and 1551 cm-1) groups were appeared in the spectrum which confirmed the coupling reaction. Efficient visible Photoluminescence was obtained at around 624 nm from glucose treated porous silicon. The functionalization of glucose with nano structured PS, changes light emission over the surface of OPS. It can be applied in optical biosensor and which can be used in biomedical applications.

  9. Unusual Function of Modified Polyolefins for Manipulating Magnetic Nanostructures

    NASA Astrophysics Data System (ADS)

    He, Qingliang; Yuan, Tingting; Wei, Suying; Guo, Zhanhu

    2014-04-01

    The unusual function of a long known plastic additive in industry, polypropylene- graft-maleic anhydride (PP- g-MA), is reviewed for serving as a polymeric surfactant to synthesize and stabilize magnetic nanoparticles (NPs) with tunable morphology and crystalline structure. The synthesis route employs a solution-based, one-pot, bottom-up method. Specifically, magnetic NPs were synthesized through thermo-decomposing organo-metallic precursors [i.e., Fe(CO)5 or Co2(CO)8] in the presence of PP- g-MA in solvent xylene. By simply changing the backbone length/concentration of PP- g-MA, different morphologies (monodispersed hollow vs. chain-like solid, or chain-like vs. monodispersed polyhedral-shaped NPs) and crystalline structures [α- vs. γ-phase for Fe2O3 NPs, or face-centered cubic (fcc)- vs. ɛ-phase for Co NPs] can be controlled simultaneously. In addition, for the chain-like Fe2O3 NPs, a different chain diameter and building block morphology can be controlled by only varying the molecular weight of PP- g-MA.

  10. Density functional theory for field emission from carbon nano-structures.

    PubMed

    Li, Zhibing

    2015-12-01

    Electron field emission is understood as a quantum mechanical many-body problem in which an electronic quasi-particle of the emitter is converted into an electron in vacuum. Fundamental concepts of field emission, such as the field enhancement factor, work-function, edge barrier and emission current density, will be investigated, using carbon nanotubes and graphene as examples. A multi-scale algorithm basing on density functional theory is introduced. We will argue that such a first principle approach is necessary and appropriate for field emission of nano-structures, not only for a more accurate quantitative description, but, more importantly, for deeper insight into field emission.

  11. Ternary eutectic growth of nanostructured thermoelectric Ag-Pb-Te materials

    SciTech Connect

    Wu, Hsin-jay; Chen, Sinn-wen; Foo, Wei-jian; Jeffrey Snyder, G.

    2012-07-09

    Nanostructured Ag-Pb-Te thermoelectric materials were fabricated by unidirectionally solidifying the ternary Ag-Pb-Te eutectic and near-eutectic alloys using the Bridgeman method. Specially, the Bridgman-grown eutectic alloy exhibited a partially aligned lamellar microstructure, which consisted of Ag{sub 5}Te{sub 3} and Te phases, with additional 200-600 nm size particles of PbTe. The self-assembled interfaces altered the thermal and electronic transport properties in the bulk Ag-Pb-Te eutectic alloy. Presumably due to phonon scattering from the nanoscale microstructure, a low thermal conductivity ({kappa} = 0.3 W/mK) was achieved of the eutectic alloy, leading to a zT peak of 0.41 at 400 K.

  12. Attosecond nanotechnology: NEMS of energy storage and nanostructural transformations in materials

    SciTech Connect

    Beznosyuk, Sergey A. Maslova, Olga A.; Zhukovsky, Mark S.

    2015-10-27

    The attosecond technology of the nanoelectromechanical system (NEMS) energy storage as active center fast transformation of nanostructures in materials is considered. The self-organizing relaxation of the NEMS active center containing nanocube of 256-atoms limited by planes (100) in the FCC lattice matrix of 4d-transition metals (Ru, Rh, Pd) is described by the quantum NEMS-kinetics (NK) method. Typical for these metals change of the NEMS active center physicochemical characteristics during the time of relaxation is presented. There are three types of intermediate quasistationary states of the NEMS active center. Their forms are plainly distinguishable. The full relaxed NEMS active centers (Ru{sub 256}, Rh{sub 256}, Pd{sub 256}) accumulate next storage energies: E{sub Ru} = 2.27 eV/at, E{sub Rh} = 1.67 eV/at, E{sub Pd} = 3.02 eV/at.

  13. Versatile, high sensitivity, and automatized angular dependent vectorial Kerr magnetometer for the analysis of nanostructured materials.

    PubMed

    Teixeira, J M; Lusche, R; Ventura, J; Fermento, R; Carpinteiro, F; Araujo, J P; Sousa, J B; Cardoso, S; Freitas, P P

    2011-04-01

    Magneto-optical Kerr effect (MOKE) magnetometry is an indispensable, reliable, and one of the most widely used techniques for the characterization of nanostructured magnetic materials. Information, such as the magnitude of coercive fields or anisotropy strengths, can be readily obtained from MOKE measurements. We present a description of our state-of-the-art vectorial MOKE magnetometer, being an extremely versatile, accurate, and sensitivity unit with a low cost and comparatively simple setup. The unit includes focusing lenses and an automatized stepper motor stage for angular dependent measurements. The performance of the magnetometer is demonstrated by hysteresis loops of Co thin films displaying uniaxial anisotropy induced on growth, MnIr/CoFe structures exhibiting the so called exchange bias effect, spin valves, and microfabricated flux guides produced by optical lithography.

  14. Non-covalently functionalized carbon nanostructures for synthesizing carbon-based hybrid nanomaterials.

    PubMed

    Li, Haiqing; Song, Sing I; Song, Ga Young; Kim, Il

    2014-02-01

    Carbon nanostructures (CNSs) such as carbon nanotubes, graphene sheets, and nanodiamonds provide an important type of substrate for constructing a variety of hybrid nanomaterials. However, their intrinsic chemistry-inert surfaces make it indispensable to pre-functionalize them prior to immobilizing additional components onto their surfaces. Currently developed strategies for functionalizing CNSs include covalent and non-covalent approaches. Conventional covalent treatments often damage the structure integrity of carbon surfaces and adversely affect their physical properties. In contrast, the non-covalent approach offers a non-destructive way to modify CNSs with desired functional surfaces, while reserving their intrinsic properties. Thus far, a number of surface modifiers including aromatic compounds, small-molecular surfactants, amphiphilic polymers, and biomacromolecules have been developed to non-covalently functionalize CNS surfaces. Mediated by these surface modifiers, various functional components such as organic species and inorganic nanoparticles were further decorated onto their surfaces, resulting in versatile carbon-based hybrid nanomaterials with broad applications in chemical engineering and biomedical areas. In this review, the recent advances in the generation of such hybrid nanostructures based on non-covalently functionalized CNSs will be reviewed. PMID:24749433

  15. A dual enzyme functionalized nanostructured thulium oxide based interface for biomedical application

    NASA Astrophysics Data System (ADS)

    Singh, Jay; Roychoudhury, Appan; Srivastava, Manish; Solanki, Pratima R.; Lee, Dong Won; Lee, Seung Hee; Malhotra, B. D.

    2013-12-01

    nanorods has been electrophoretically deposited (EPD) onto an indium-tin-oxide (ITO) glass substrate. The n-Tm2O3 nanorods are found to provide improved sensing characteristics to the electrode interface in terms of electroactive surface area, diffusion coefficient, charge transfer rate constant and electron transfer kinetics. The structural and morphological studies of n-Tm2O3 nanorods have been carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopic techniques. This interfacial platform has been used for fabrication of a total cholesterol biosensor by immobilizing cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) onto a Tm2O3 nanostructured surface. The results of response studies of the fabricated ChEt-ChOx/n-Tm2O3/ITO bioelectrode show a broad linear range of 8-400 mg dL-1, detection limit of 19.78 mg (dL cm-2)-1, and high sensitivity of 0.9245 μA (mg per dL cm-2)-1 with a response time of 40 s. Further, this bioelectrode has been utilized for estimation of total cholesterol with negligible interference (3%) from analytes present in human serum samples. The utilization of this n-Tm2O3 modified electrode for enzyme-based biosensor analysis offers an efficient strategy and a novel interface for application of the rare earth metal oxide materials in the field of electrochemical sensors and bioelectronic devices. Electronic supplementary information (ESI) available: XPS spectra of n-Tm2O3, differential pulse voltammograms, magnitude of potential difference as a function of scan rate (10-100 mV s-1), effect of working potential, amount of enzyme used for immobilization, amount of enzyme loading, effect of interferents, response time, effect of temperature, determination of cholesterol in serum samples and photometric enzyme activity studies. See DOI: 10.1039/c3nr05043b

  16. Simulation of Semiconductor Nanostructures

    SciTech Connect

    Williamson, A J; Grossman, J C; Puzder, A; Benedict, L X; Galli, G

    2001-07-19

    The field of research into the optical properties of silicon nanostructures has seen enormous growth over the last decade. The discovery that silicon nanoparticles exhibit visible photoluminescence (PL) has led to new insights into the mechanisms responsible for such phenomena. The importance of understanding and controlling the PL properties of any silicon based material is of paramount interest to the optoelectronics industry where silicon nanoclusters could be embedded into existing silicon based circuitry. In this talk, we present a combination of quantum Monte Carlo and density functional approaches to the calculation of the electronic, structural, and optical properties of silicon nanostructures.

  17. Synthesis of nano-structured materials by laser-ablation and their application to sensors

    NASA Astrophysics Data System (ADS)

    Okada, T.; Suehiro, J.

    2007-07-01

    We describe the synthesis of nano-structured materials of ZnO and Pd by laser ablation and their applications to sensors. The synthesis of ZnO nano-wires was performed by nano-particle assisted deposition (NPAD) where nano-crystals were grown with nano-particles generated by laser-ablating a ZnO sintered target in an Ar background gas. The synthesized ZnO nano-wires were characterized with a scanning electron microscopy and the photoluminescent characteristics were examined under an excitation with the third harmonics of a Nd:YAG laser. The nano-wires with a diameter in the range from 50 to 150 nm and a length of up to 5 μm were taken out of the substrate by laser blow-off technique and/or sonication. It was confirmed that the nano-wires showed the stimulated emission under optical pumping, indicating a high quality of the crystalinity. Pd nano-particles were generated by laser-ablating a Pd plate in pure water. The transmission electron microscope observation revealed that Pd nano-particles with a diameter in the range from 3 nm to several tens of nanometers were produced. Using these nano-structured materials, we successfully fabricated sensors by the dielectrophoresis techniques. In the case of the ultraviolet photosensor, a detection sensitivity of 10 nW/cm 2 was achieved and in the case of hydrogen sensing, the response time of less than 10 s has been demonstrated with Pd nano-particles.

  18. Tunable plasmons in few-layer nitrogen-doped graphene nanostructures: A time-dependent density functional theory study

    NASA Astrophysics Data System (ADS)

    Shu, Xiao-qin; Zhang, Hong; Cheng, Xin-lu; Miyamoto, Yoshiyuki

    2016-05-01

    Compared with conventional metal plasmonic materials, surface plasmons in graphene are advantageous in terms of higher confinement, relative low loss, flexible featuring, and good tunability. However, the working frequencies of the pristine graphene (undoped graphene) surface plasmons are located in the terahertz and infrared regions, which limit their applications. Here we show high-frequency plasmons in nitrogen (N)-doped graphene nanostructures investigated by time-dependent density functional theory. We found the optical absorption strength of systems containing two layers to be more than twofold stronger than that of systems with monolayers. The optical absorption strength increases as the interlayer distance increases, and the absorption spectra are red-shifted for impulse excitations polarized in the armchair edge direction (x axis). For microstructures of more than two layers, the optical absorption strength increases as number of layers of the N-doped graphene nanostructures increases. In addition, when the number of layers becomes elevated at low-energy resonances, the absorption spectra are seen to blue-shift. The plasmon energy resonance points are located in the visible and ultraviolet regions. The N-doped graphene provides an effective strategy for nanoscale plasmon devices in the visible and ultraviolet regions, despite their weaker absorption intensities when compared with the pristine graphene.

  19. Attenuation of shock waves propagating through nano-structured porous materials

    NASA Astrophysics Data System (ADS)

    Al-Qananwah, Ahmad K.; Koplik, Joel; Andreopoulos, Yiannis

    2013-07-01

    Porous materials have long been known to be effective in energy absorption and shock wave attenuation. These properties make them attractive in blast mitigation strategies. Nano-structured materials have an even greater potential for blast mitigation because of their high surface-to-volume ratio, a geometric parameter which substantially attenuates shock wave propagation. A molecular dynamics approach was used to explore the effects of this remarkable property on the behavior of traveling shocks impacting on solid materials. The computational setup included a moving piston, a gas region and a target solid wall with and without a porous structure. The gas and porous solid were modeled by Lennard-Jones-like and effective atom potentials, respectively. The shock wave is resolved in space and time and its reflection from a solid wall is gradual, due to the wave's finite thickness, and entails a self-interaction as the reflected wave travels through the incoming incident wave. Cases investigated include a free standing porous structure, a porous structure attached to a wall and porous structures with graded porosity. The effects of pore shape and orientation have been also documented. The results indicate that placing a nano-porous material layer in front of the target wall reduced the stress magnitude and the energy deposited inside the solid by about 30 percent, while at the same time substantially decreasing the loading rate.

  20. One dimensional semiconductor nanostructures: An effective active-material for terahertz detection

    SciTech Connect

    Vitiello, Miriam S. Viti, Leonardo; Ercolani, Daniele; Sorba, Lucia; Coquillat, Dominique; Knap, Wojciech

    2015-02-01

    One-dimensional (1D) nanostructure devices are at the frontline of studies on future electronics, although issues like massive parallelization, doping control, surface effects, and compatibility with silicon industrial requirements are still open challenges. The recent progresses in atomic to nanometer scale control of materials morphology, size, and composition including the growth of axial, radial, and branched nanowire (NW)-based heterostructures make the NW an ideal building block for implementing rectifying diodes or detectors that could be well operated into the Terahertz (THz), thanks to their typical achievable attofarad-order capacitance. Here, we report on our recent progresses in the development of 1D InAs or InAs/InSb NW-based field effect transistors exploiting novel morphologies and/or material combinations effective for addressing the goal of a semiconductor plasma-wave THz detector array technology. Through a critical review of material-related parameters (NW doping concentration, geometry, and/or material choice) and antenna-related issues, here we underline the crucial aspects that can affect detection performance across the THz frequency region.

  1. On-chip surface modified nanostructured ZnO as functional pH sensors.

    PubMed

    Zhang, Qing; Liu, Wenpeng; Sun, Chongling; Zhang, Hao; Pang, Wei; Zhang, Daihua; Duan, Xuexin

    2015-09-01

    Zinc oxide (ZnO) nanostructures are promising candidates as electronic components for biological and chemical applications. In this study, ZnO ultra-fine nanowire (NW) and nanoflake (NF) hybrid structures have been prepared by Au-assisted chemical vapor deposition (CVD) under ambient pressure. Their surface morphology, lattice structures, and crystal orientation were investigated by scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM). Two types of ZnO nanostructures were successfully integrated as gate electrodes in extended-gate field-effect transistors (EGFETs). Due to the amphoteric properties of ZnO, such devices function as pH sensors. We found that the ultra-fine NWs, which were more than 50 μm in length and less than 100 nm in diameter, performed better in the pH sensing process than NW-NF hybrid structures because of their higher surface-to-volume ratio, considering the Nernst equation and the Gouy-Chapman-Stern model. Furthermore, the surface coating of (3-Aminopropyl)triethoxysilane (APTES) protects ZnO nanostructures in both acidic and alkaline environments, thus enhancing the device stability and extending its pH sensing dynamic range.

  2. 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.

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

    SciTech Connect

    Orilall, M. Christopher; Wiesner, Ulrich

    2011-01-01

    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.

  4. Controlling the nanostructure of gold nanorod-lyotropic liquid-crystalline hybrid materials using near-infrared laser irradiation.

    PubMed

    Fong, Wye-Khay; Hanley, Tracey L; Thierry, Benjamin; Kirby, Nigel; Waddington, Lynne J; Boyd, Ben J

    2012-10-01

    Lipid-based liquid-crystalline matrixes provide a unique prospect for stimuli-responsive nanomaterials, attributed to the ability to effect self-assembly of the lipids at the molecular level. Differences in liquid crystal nanostructure have previously been shown to change drug diffusion and hence release, with research progressing toward the use of in situ changes to nanostructure to control drug release. Toward this goal, we have previously communicated the ability to switch between nonlamellar structures using gold nanorod (GNR)-phytantriol-based liquid-crystalline hybrid nanomaterials as near-infrared light responsive systems (Fong et al. Langmuir 2010, 26, 6136-6139). In this study, the effect of laser activation on matrix nanostructure with changes in a number of system variables including lipid composition, GNR aspect ratio, GNR concentration, and laser pulse time were investigated. The nanostructure of the matrix was followed using small-angle X-ray scattering, while both cryoFESEM and cryoTEM were used to visualize the effect of GNR incorporation into the liquid crystal nanostructure. The system response was found to be dependent on all variables, thus demonstrating the potential of these nanocomposite materials as reversible "on-demand" drug delivery applications.

  5. One-Dimensional Oxide Nanostructures as Gas-Sensing Materials: Review and Issues

    PubMed Central

    Choi, Kyoung Jin; Jang, Ho Won

    2010-01-01

    In this article, we review gas sensor application of one-dimensional (1D) metal-oxide nanostructures with major emphases on the types of device structure and issues for realizing practical sensors. One of the most important steps in fabricating 1D-nanostructure devices is manipulation and making electrical contacts of the nanostructures. Gas sensors based on individual 1D nanostructure, which were usually fabricated using electron-beam lithography, have been a platform technology for fundamental research. Recently, gas sensors with practical applicability were proposed, which were fabricated with an array of 1D nanostructures using scalable micro-fabrication tools. In the second part of the paper, some critical issues are pointed out including long-term stability, gas selectivity, and room-temperature operation of 1D-nanostructure-based metal-oxide gas sensors. PMID:22319343

  6. Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal

    NASA Astrophysics Data System (ADS)

    Tercjak, A.; Garcia, I.; Mondragon, I.

    2008-07-01

    Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface.

  7. Nanostructured materials and their role as heterogeneous catalysts in the conversion of biomass to biofuels

    NASA Astrophysics Data System (ADS)

    Cadigan, Chris

    Prior to the discovery of inexpensive and readily available fossil fuels, the world relied heavily on biomass to provide its energy needs. Due to a worldwide growth in demand for fossil fuels coupled with the shrinkage of petroleum resources, and mounting economic, political, and environmental concerns, it has become more pressing to develop sustainable fuels and chemicals from biomass. The present dissertation studies multiple nanostructured catalysts investigated in various processes related to gasification of biomass into synthesis gas, and further upgrading to biofuels and value added chemicals. These reactions include: syngas conditioning, alcohol synthesis from carbon monoxide hydrogenation, and steam reforming ethanol to form higher hydrocarbons. Nanomaterials were synthesized, characterized, studied in given reactions, and then further characterized post-reaction. Overall goals were aimed at determining catalytic activities towards desired products and determining which material properties were most desirable based on experimental results. Strategies to improve material design for second-generation materials are suggested based on promising reaction results coupled with pre and post reaction characterization analysis.

  8. NiO-silica based nanostructured materials obtained by microemulsion assisted sol-gel procedure

    SciTech Connect

    Mihaly, M.; Comanescu, A.F.; Rogozea, A.E.; Vasile, E.; Meghea, A.

    2011-10-15

    Graphical abstract: TEM micrograph of NiO/SiO{sub 2} nanoparticles. Highlights: {yields} Microemulsion assisted sol-gel procedure for NiO silica nanomaterials synthesis. {yields} Controlling the size and shape of nanoparticles and avoiding their aggregation. {yields} Narrow band-gap semiconductors (energies <3 eV) absorbing VIS or near-UV light biologically and chemically inert semiconductors entrapping/coating in silica network. {yields} Low cost as the microemulsion is firstly used in water metallic cation extraction. -- Abstract: NiO-silica based materials have been synthesized by microemulsion assisted sol-gel procedure. The versatility of these soft nanotechnology techniques has been exploited in order to obtain different types of nanostructures, such as NiO nanoparticles, NiO silica coated nanoparticles and NiO embedded in silica matrix. These materials have been characterized by adequate structural and morphology techniques: DLS, HR-TEM/SAED, BET, AFM. Optical and semiconducting properties (band-gap values) of the synthesized materials have been quantified by means of VIS-NIR diffuse reflectance spectra, thus demonstrating their applicative potential in various electron transfer phenomena such as photocatalysis, electrochromic thin films, solid oxide fuel cells.

  9. Synthesis and characterization of nanostructured cathode materials for rechargeable lithium/lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Yang, Jingsi

    The rapidly increasing markets of portable electronic devices and electric/hybrid vehicles have raised worldwide R&D efforts in developing high-energy rechargeable lithium and lithium ion batteries. High performance intercalation cathodes are key to the success of these batteries. The nanotechnology has endowed the electrode materials with a variety of improved features as well as unique characteristics. Synthesis approaches were designed in this thesis work to utilize these advantages and investigate the exceptional phenomena raised by the nanostructured materials. A novel sol-gel method was designed for the synthesis of carbon-coated phase-pure lithium iron phosphate with submicron particle sizes and uniform size distribution. The surface carbon coating was formed in-situ through pyrolysis of the precursor gel, which improved the apparent electronic conductivity of the as prepared material to 10-2 S/cm compared with 10-9-10-10 S/cm of the pristine LiFePO 4. The favorable physical characteristics of the synthesized LiFePO 4 particles and the improved electronic conductivity through the carbon coating led to electrochemical properties comparable to the best performances reported so far. Amorphous manganese oxide cryogels with nanoarchitecture were obtained by freeze-drying Mn (IV) oxide hydrogels. The combination of the advantages of the amorphous structure and the nano-architecture of the materials gave high capacities and excellent rate capabilities. This work led to the finding of a nanocrystalline Li2MnO3-like compound with a surprising electrochemical activity, which is in sharp contrast to the microcrystalline rock-salt Li2MnO3 that has been known to be electrochemically inactive. The study highlights the possibility of qualitative difference in intercalation behavior of nanostructured intercalation compounds compared with their microcrystalline counterparts. Bismuth and copper modified amorphous manganese oxides were synthesized by aqueous coprecipitation

  10. Design and assembly of nanostructured complex metal oxide materials for the construction of batteries and thermoelectric devices

    NASA Astrophysics Data System (ADS)

    Yadav, Gautam Ganapati

    Thermoelectric devices and lithium-ion batteries are among the fastest growing energy technologies. Thermoelectric devices generate energy from waste heat, whereas lithium-ion batteries store energy for use in commercial applications. Two different topics are bound with a common thread in this thesis - nanotechnology! In fact, nanostructuring is a more preferred term for the approach I have taken herein. Another commonality between these two topics is the material system I have used to prove my hypotheses - complex metal oxides. Complex metal oxides can be used for both energy generation and storage as they are stable at high temperatures, are benign and inexpensive, and are chemically stable. . Nevertheless, complex metal oxide-based materials have drawbacks when they are used in thermoelectric devices. Since they have high thermal conductivities and low power factors, they have lower thermoelectric figures of merit (ZT). This affects their performance as thermoelectric materials. Nanostructuring can solve this critical problem as thermal conductivity, electrical conductivity and Seebeck coefficient become quasi-independent of each other under these conditions. However, oxide-based materials have proven to be greatly recalcitrant to forming nanostructures when traditional synthetic methods such as solid-state reactions have been employed. Solid-state reactions usually proceed at extremely high temperatures that are not particularly conducive to forming nanostructures. The first part of this thesis presents novel solution-based synthetic methods that were developed in order to produce novel nanostructured complex metal oxides. Typical structures include nanowires. The second part of this thesis extends this methodology to study the effect of nanostructuring on the thermal conductivity of strontium titanate (SrTiO3), a promising high temperature thermoelectric material. Ultrathin nanowires of SrTiO3 were synthesized using a novel hydrothermal reaction. These

  11. Surface functionalization of nanostructured LaB6-coated Poly Trilobal fabric by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Wu, Yan; Zhang, Lin; Min, Guanghui; Yu, Huashun; Gao, Binghuan; Liu, Huihui; Xing, Shilong; Pang, Tao

    2016-10-01

    Nanostructured LaB6 films were deposited on flexible Poly Trilobal substrates (PET textiles) through direct current magnetron sputtering in order to broaden its applications and realize surface functionalization of polyester fabrics. Characterizations and performances were investigated by employing a scanning electron microscope (SEM), Fourier transformation infrared spectroscopy (FT-IR) and ultraviolet-visible (UV-vis) spectrophotometer. Ultraviolet Protection Factor (UPF) conducted by the integral conversion was employed to measure the ultraviolet protection ability. As expected, the growth of LaB6 film depending on the pressure variation enhanced UV-blocking ability (UPF rating at 30.17) and absorption intensity of the textiles.

  12. Swell Gels to Dumbbell Micelles: Construction of Materials and Nanostructure with Self-assembly

    NASA Astrophysics Data System (ADS)

    Pochan, Darrin

    2007-03-01

    Bionanotechnology, the emerging field of using biomolecular and biotechnological tools for nanostructure or nanotecnology development, provides exceptional opportunity in the design of new materials. Self-assembly of molecules is an attractive materials construction strategy due to its simplicity in application. By considering peptidic or charged synthetic polymer molecules in the bottom-up materials self-assembly design process, one can take advantage of inherently biomolecular attributes; intramolecular folding events, secondary structure, and electrostatic interactions; in addition to more traditional self-assembling molecular attributes such as amphiphilicty, to define hierarchical material structure and consequent properties. Several molecular systems will be discussed. Synthetic block copolymers with charged corona blocks can be assembled in dilute solution containing multivalent organic counterions to produce micelle structures such as toroids. These ring-like micelles are similar to the toroidal bundling of charged semiflexible biopolymers like DNA in the presence of multivalent counterions. Micelle structure can be tuned between toroids, cylinders, and disks simply by using different concentrations or molecular volumes of organic counterion. In addition, these charged blocks can consist of amino acids as monomers producing block copolypeptides. In addition to the above attributes, block copolypeptides provide the control of block secondary structure to further control self-assembly. Design strategies based on small (less than 24 amino acids) beta-hairpin peptides will be discussed. Self-assembly of the peptides is predicated on an intramolecular folding event caused by desired solution properties. Importantly, the intramolecular folding event impart a molecular-level mechanism for environmental responsiveness at the material level (e.g. infinite change in viscosity of a solution to a gel with changes in pH, ionic strength, temperature).

  13. Development of Nano-structured Electrode Materials for High Performance Energy Storage System

    NASA Astrophysics Data System (ADS)

    Huang, Zhendong

    Systematic studies have been done to develop a low cost, environmental-friendly facile fabrication process for the preparation of high performance nanostructured electrode materials and to fully understand the influence factors on the electrochemical performance in the application of lithium ion batteries (LIBs) or supercapacitors. For LIBs, LiNi1/3Co1/3Mn1/3O2 (NCM) with a 1D porous structure has been developed as cathode material. The tube-like 1D structure consists of inter-linked, multi-facet nanoparticles of approximately 100-500nm in diameter. The microscopically porous structure originates from the honeycomb-shaped precursor foaming gel, which serves as self-template during the stepwise calcination process. The 1D NCM presents specific capacities of 153, 140, 130 and 118mAh·g-1 at current densities of 0.1C, 0.5C, 1C and 2C, respectively. Subsequently, a novel stepwise crystallization process consisting of a higher crystallization temperature and longer period for grain growth is employed to prepare single crystal NCM nanoparticles. The modified sol-gel process followed by optimized crystallization process results in significant improvements in chemical and physical characteristics of the NCM particles. They include a fully-developed single crystal NCM with uniform composition and a porous NCM architecture with a reduced degree of fusion and a large specific surface area. The NCM cathode material with these structural modifications in turn presents significantly enhanced specific capacities of 173.9, 166.9, 158.3 and 142.3mAh·g -1 at 0.1C, 0.5C, 1C and 2C, respectively. Carbon nanotube (CNT) is used to improve the relative low power capability and poor cyclic stability of NCM caused by its poor electrical conductivity. The NCM/CNT nanocomposites cathodes are prepared through simply mixing of the two component materials followed by a thermal treatment. The CNTs were functionalized to obtain uniformly-dispersed MWCNTs in the NCM matrix. The electrochemical

  14. AFM characterization of nonwoven material functionalized by ZnO sputter coating

    SciTech Connect

    Deng Bingyao; Yan Xiong; Wei Qufu Gao Weidong

    2007-10-15

    Sputter coatings provide new approaches to the surface functionalization of textile materials. In this study, polyethylene terephthalate (PET) nonwoven material was used as a substrate for creating functional nanostructures on the fiber surfaces. A magnetron sputter coating was used to deposit functional zinc oxide (ZnO) nanostructures onto the nonwoven substrate. The evolution of the surface morphology of the fibers in the nonwoven web was examined using atomic force microscopy (AFM). The AFM observations revealed a significant difference in the morphology of the fibers before and after the sputter coating. The AFM images also indicated the effect of the sputtering conditions on the surface morphology of the fibers. The increase in the sputtering time led to the growth of the ZnO grains on the fiber surfaces. The higher pressure in the sputtering chamber could cause the formation of larger grains on the fiber surfaces. The higher power used also generated larger grains on the fiber surfaces.

  15. Optoacoustic Microscopy for Investigation of Material Nanostructures-Embracing the Ultrasmall, Ultrafast, and the Invisible

    SciTech Connect

    Nurmikko, Arto; Humphrey, Maris

    2014-07-10

    The goal of this grant was the development of a new type of scanning acoustic microscope for nanometer resolution ultrasound imaging, based on ultrafast optoacoustics (>GHz). In the microscope, subpicosecond laser pulses was used to generate and detect very high frequency ultrasound with nanometer wavelengths. We report here on the outcome of the 3-year DOE/BES grant which involved the design, multifaceted construction, and proof-of-concept demonstration of an instrument that can be used for quantitative imaging of nanoscale material features – including features that may be buried so as to be inaccessible to conventional lightwave or electron microscopies. The research program has produced a prototype scanning optoacoustic microscope which, in combination with advanced computational modeling, is a system-level new technology (two patents issues) which offer novel means for precision metrology of material nanostructures, particularly those that are of contemporary interest to the frontline micro- and optoelectronics device industry. For accomplishing the ambitious technical goals, the research roadmap was designed and implemented in two phases. In Phase I, we constructed a “non-focusing” optoacoustic microscope instrument (“POAM”), with nanometer vertical (z-) resolution, while limited to approximately 10 micrometer scale lateral recolution. The Phase I version of the instrument which was guided by extensive acoustic and optical numerical modeling of the basic underlying acoustic and optical physics, featured nanometer scale close loop positioning between the optoacoustic transducer element and a nanostructured material sample under investigation. In phase II, we implemented and demonstrated a scanning version of the instrument (“SOAM”) where incident acoustic energy is focused, and scanned on lateral (x-y) spatial scale in the 100 nm range as per the goals of the project. In so doing we developed advanced numerical simulations to provide

  16. Biosynthetic Polymers as Functional Materials

    PubMed Central

    2016-01-01

    The synthesis of functional polymers encoded with biomolecules has been an extensive area of research for decades. As such, a diverse toolbox of polymerization techniques and bioconjugation methods has been developed. The greatest impact of this work has been in biomedicine and biotechnology, where fully synthetic and naturally derived biomolecules are used cooperatively. Despite significant improvements in biocompatible and functionally diverse polymers, our success in the field is constrained by recognized limitations in polymer architecture control, structural dynamics, and biostabilization. This Perspective discusses the current status of functional biosynthetic polymers and highlights innovative strategies reported within the past five years that have made great strides in overcoming the aforementioned barriers. PMID:27375299

  17. Comparative electrochemical studies of a nanostructured vanadium oxide electrode material in aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Soghomonian, Victoria; Yuan, Qifan; Ren, Shaola; Zukowski, Julia

    Electrochemical energy storage plays an increasing role in energy solutions. We report on a new hydrothermally synthesized vanadium oxide nanostructured material and study its performance as electrode material for insertion of various ions from aqueous solutions. The as-synthesized product is in the form of nanosheets forming quasi-spherical 3-dimensional objects. Variable temperature resistivity measurements indicate a thermally activated behavior. Electrodes are constructed, and comparative electrochemical insertion reactions of Li, Na, K and NH4 cations, over different cycle numbers, investigated. Concomitantly, morphological and microstructural changes are characterized by scanning electron microscopy, providing physical input to the observed electrochemical behavior. Specific charge is calculated. For Li and K, the specific charge decreases as the cycle number increases, while the reverse is observed for Na and NH4 cations. The trends are correlated to the morphological changes observed. The specific charge in the case of ammonium reaches 180 mAh/g after 20 cycles and continues increasing, indicating that ammonium cations may be considered as viable charge carriers for electrical energy storage system, and moreover in an aqueous electrolyte. We acknowledge support from the National Science Foundation, Grant No. DMR-1206338.

  18. 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.

  19. Fundamental investigation of the tribological and mechanical responses of materials and nanostructures

    NASA Astrophysics Data System (ADS)

    Bucholz, Eric W.

    In the field of tribology, the ability to predict, and ultimately control, frictional performance is of critical importance for the optimization of tribological systems. As such, understanding the specific mechanisms involved in the lubrication processes for different materials is a fundamental step in tribological system design. In this work, a combination of computational and experimental methods that include classical molecular dynamics (MD) simulations, atomic force microscopy (AFM) experiments, and multivariate statistical analyses provides fundamental insight into the tribological and mechanical properties of carbon-based and inorganic nanostructures, lamellar materials, and inorganic ceramic compounds. One class of materials of modern interest for tribological applications is nanoparticles, which can be employed either as solid lubricating films or as lubricant additives. In experimental systems, however, it is often challenging to attain the in situ observation of tribological interfaces necessary to identify the atomic-level mechanisms involved during lubrication and response to mechanical deformation. Here, classical MD simulations establish the mechanisms occurring during the friction and compression of several types of nanoparticles including carbon nano-onions, amorphous carbon nanoparticles, and inorganic fullerene-like MoS2 nanoparticles. Specifically, the effect of a nanoparticle's structural properties on the lubrication mechanisms of rolling, sliding, and lamellar exfoliation is indicated; the findings quantify the relative impact of each mechanism on the tribological and mechanical properties of these nanoparticles. Beyond identifying the lubrication mechanisms of known lubricating materials, the continual advancement of modern technology necessitates the identification of new candidate materials for use in tribological applications. To this effect, atomic-scale AFM friction experiments on the aluminosilicate mineral pyrophyllite demonstrate that

  20. ATRP in the design of functional materials for biomedical applications

    PubMed Central

    Siegwart, Daniel J.; Oh, Jung Kwon; Matyjaszewski, Krzysztof

    2013-01-01

    Atom Transfer Radical Polymerization (ATRP) is an effective technique for the design and preparation of multifunctional, nanostructured materials for a variety of applications in biology and medicine. ATRP enables precise control over macromolecular structure, order, and functionality, which are important considerations for emerging biomedical designs. This article reviews recent advances in the preparation of polymer-based nanomaterials using ATRP, including polymer bioconjugates, block copolymer-based drug delivery systems, cross-linked microgels/nanogels, diagnostic and imaging platforms, tissue engineering hydrogels, and degradable polymers. It is envisioned that precise engineering at the molecular level will translate to tailored macroscopic physical properties, thus enabling control of the key elements for realized biomedical applications. PMID:23525884

  1. Nanostructured materials for multifunctional applications under NSF-CREST research at Norfolk State University

    NASA Astrophysics Data System (ADS)

    Pradhan, A. K.; Mundle, R.; Zhang, K.; Holloway, T.; Amponsah, O.; Biswal, D.; Konda, R.; White, C.; Dondapati, H.; Santiago, K.; Birdsong, T.; Arslan, M.; Peeples, B.; Shaw, D.; Smak, J.; Samataray, C.; Bahoura, M.

    2012-04-01

    O nanolayers were also grown by atomic layer deposition techniques. These nanolayers of ZnO demonstrate remarkable optical and electrical properties. These nanolayers were patterned by the Electron Beam Lithography (EBL) technique. A major goal of nanotechnology is to couple the self-assembly of molecular nanostructures with conventional lithography, using either or both bottom-up and top-down fabrication methods, that would enable us to register individual molecular nanostructures onto the functional devices. However, combining the nanofabrication technique with high resolution Electron Beam Lithography, we can achieve 3D bimolecular or/and DNA origami that will be able to identify nucleic acid sequences, antigen targets, and other molecules, as for a perfect nano-biosensor. We have explored some of the nanopatterning using EBL in order to fabricate biomolecule sensing on a single chip with sub nm pitch. The applications are not limited for the bioactivity, but for enhancing immunoreactions, cell culture dishes, and tissue engineering applications.

  2. [The emergency plastic reconstruction of the tympanic membrane defects of post-traumatic and iatrogenic etiology with the application of the nanostructured bioplastic material].

    PubMed

    Zabirov, R A; Kar'kaeva, S M; Shchetinin, V N; Akimov, A V

    2014-01-01

    The objective of the present study was to estimate the effectiveness of the application of the nanostructured bioplastic material for the plastic reconstruction of tympanic defects of post-traumatic and iatrogenic etiology. The authors report the results of the emergency plastic reconstruction of tympanic defects of post-traumatic and iatrogenic nature with the application of the nanostructured bioplastic material (giamatrix). The analysis of the results of the study prfovidd definitive evidence of the effectiveness of plastic reconstruction of tympanic defects with the application of the nanostructured bioplastic material.

  3. [The emergency plastic reconstruction of the tympanic membrane defects of post-traumatic and iatrogenic etiology with the application of the nanostructured bioplastic material].

    PubMed

    Zabirov, R A; Kar'kaeva, S M; Shchetinin, V N; Akimov, A V

    2014-01-01

    The objective of the present study was to estimate the effectiveness of the application of the nanostructured bioplastic material for the plastic reconstruction of tympanic defects of post-traumatic and iatrogenic etiology. The authors report the results of the emergency plastic reconstruction of tympanic defects of post-traumatic and iatrogenic nature with the application of the nanostructured bioplastic material (giamatrix). The analysis of the results of the study prfovidd definitive evidence of the effectiveness of plastic reconstruction of tympanic defects with the application of the nanostructured bioplastic material. PMID:25588474

  4. Maximizing the catalytic function of hydrogen spillover in platinum-encapsulated aluminosilicates with controlled nanostructures.

    PubMed

    Im, Juhwan; Shin, Hyeyoung; Jang, Haeyoun; Kim, Hyungjun; Choi, Minkee

    2014-02-25

    Hydrogen spillover has been studied for several decades, but its nature, catalytic functions and even its existence remain topics of vigorous debate. This is a consequence of the lack of model catalysts that can provide direct evidences of the existence of hydrogen spillover and simplify the catalytic interpretation. Here we use platinum encapsulated in a dense aluminosilicate matrix with controlled diffusional properties and surface hydroxyl concentrations to elucidate the catalytic functions of hydrogen spillover. The catalytic investigation and theoretical modelling show that surface hydroxyls, presumably Brønsted acids, are crucial for utilizing the catalytic functions of hydrogen spillover on the aluminosilicate surface. The catalysts with optimized nanostructure show remarkable activities in hydro-/dehydrogenation, but virtually no activity for hydrogenolysis. This distinct chemoselectivity may be beneficial in industrially important hydroconversions such as propane dehydrogenation to propylene because the undesired hydrogenolysis pathway producing light hydrocarbons of low value (methane and ethane) is greatly suppressed.

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

    PubMed

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

    2016-02-01

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

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

    PubMed

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

    2016-02-01

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

  7. Continuous spray forming of functionally gradient materials

    SciTech Connect

    McKechnie, T.N.; Richardson, E.H.; Watson, R.D.

    1995-12-31

    Researchers at Plasma Processes Inc. have produced a Functional Gradient Material (FGM) through advanced vacuum plasma spray processing for high heat flux applications. Outlined in this paper are the manufacturing methods used to develop a four component functional gradient material of copper, tungsten, boron, and boron nitride. The FGM was formed with continuous gradients and integral cooling channels eliminating bondlines and providing direct heat transfer from the high temperature exposed surface to a cooling medium. Metallurgical and X-ray diffraction analyses of the materials formed through innovative VPS processing are also presented. Applications for this functional gradient structural material range from fusion reactor plasma facing components to missile nose cones to boilers.

  8. Magnetic studies of mesoporous nanostructured iron oxide materials synthesized by one-step soft-templating.

    PubMed

    Jin, Jing; Hines, William A; Kuo, Chung-Hao; Perry, David M; Poyraz, Altug S; Xia, Yan; Zaidi, Taha; Nieh, Mu-Ping; Suib, Steven L

    2015-07-14

    A combined magnetization and (57)Fe spin-echo nuclear magnetic resonance (NMR) study has been carried out on mesoporous nanostructured materials consisting of the magnetite (Fe3O4) and maghemite (γ-Fe2O3) phases. Two series of samples were synthesized using a recently developed one-step soft-templating approach with systematic variations in calcination temperature and reaction atmosphere. Nuclear magnetic resonance has been shown to be a valuable tool for distinguishing between the two magnetic iron oxide spinel phases, Fe3O4 and γ-Fe2O3, on the nanoscale as well as monitoring phase transformation resulting from oxidation. For the Fe3O4 and γ-Fe2O3 phases, peaks in the NMR spectra are attributed to Fe in the tetrahedral (A) sites and octahedral (B) sites. The magnetic field dependence of the peaks was observed and confirmed the site assignments. Fe3O4 on a nanoscale readily oxidizes to form γ-Fe2O3 and this was clearly evident in the NMR spectra. As evidenced by transmission electron microscope (TEM) images, the porous mesostructure for the iron oxide materials is formed by a random close-packed aggregation of nanoparticles; correspondingly, superparamagnetic behavior was observed in the magnetic measurements. Although X-ray diffraction (XRD) shows the spinel structure for the Fe3O4 and γ-Fe2O3 phases, unlike NMR, it is difficult to distinguish between the two phases with XRD. Nitrogen sorption isotherms characterize the mesoporous structures of the materials, and yield BET surface area values and limited BJH pore size distribution curves.

  9. Converting environmentally hazardous materials into clean energy using a novel nanostructured photoelectrochemical fuel cell

    SciTech Connect

    Gan, Yong X.; Gan, Bo J.; Clark, Evan; Su, Lusheng; Zhang, Lihua

    2012-09-15

    Highlights: ► A photoelectrochemical fuel cell has been made from TiO{sub 2} nanotubes. ► The fuel cell decomposes environmentally hazardous materials to produce electricity. ► Doping the anode with a transition metal oxide increases the visible light sensitivity. ► Loading the anode with a conducting polymer enhances the visible light absorption. -- Abstract: In this work, a novel photoelectrochemical fuel cell consisting of a titanium dioxide nanotube array photosensitive anode and a platinum cathode was made for decomposing environmentally hazardous materials to produce electricity and clean fuel. Titanium dioxide nanotubes (TiO{sub 2} NTs) were prepared via electrochemical oxidation of pure Ti in an ammonium fluoride and glycerol-containing solution. Scanning electron microscopy was used to analyze the morphology of the nanotubes. The average diameter, wall thickness and length of the as-prepared TiO{sub 2} NTs were determined. The photosensitive anode made from the highly ordered TiO{sub 2} NTs has good photo-catalytic property, as proven by the decomposition tests on urea, ammonia, sodium sulfide and automobile engine coolant under ultraviolet (UV) radiation. To improve the efficiency of the fuel cell, doping the TiO{sub 2} NTs with a transition metal oxide, NiO, was performed and the photosensitivity of the doped anode was tested under visible light irradiation. It is found that the NiO-doped anode is sensitive to visible light. Also found is that polyaniline-doped photosensitive anode can harvest photon energy in the visible light spectrum range much more efficiently than the NiO-doped one. It is concluded that the nanostructured photoelectrochemical fuel cell can generate electricity and clean fuel by decomposing hazardous materials under sunlight.

  10. Ceramic transactions: Functionally gradient materials. Volume 34

    SciTech Connect

    Holt, J.B.; Koizumi, Mitsue; Hirai, Toshio; Munir, Z.A.

    1993-01-01

    A functionally gradient material (FGM) is a composite that smoothly transitions from one material at one surface to another material at the opposite surface. Metals and ceramics are usually the materials that are combined in a controlled manner to optimize a specific property. The First International Symposium on Functionally Gradient Materials was held in Sendai, Japan, in August 1990. Contained in the present volume are the Proceedings of the Second International Symposium on Functionally Gradient Materials, presented at the Third International Ceramic Science and Technology Congress, held in San Francisco, CA, November 1-4, 1992. The papers presented here are divided into eight sections: the concept of FGM; mathematical modeling; methods of fabrication; material evaluation; applications; joining processes in FGM; process characterization; and design considerations. Separate abstracts are provided for each of the 54 papers.

  11. Probing the self-assembled nanostructures of functional polymers with synchrotron grazing incidence X-ray scattering.

    PubMed

    Ree, Moonhor

    2014-05-01

    For advanced functional polymers such as biopolymers, biomimic polymers, brush polymers, star polymers, dendritic polymers, and block copolymers, information about their surface structures, morphologies, and atomic structures is essential for understanding their properties and investigating their potential applications. Grazing incidence X-ray scattering (GIXS) is established for the last 15 years as the most powerful, versatile, and nondestructive tool for determining these structural details when performed with the aid of an advanced third-generation synchrotron radiation source with high flux, high energy resolution, energy tunability, and small beam size. One particular merit of this technique is that GIXS data can be obtained facilely for material specimens of any size, type, or shape. However, GIXS data analysis requires an understanding of GIXS theory and of refraction and reflection effects, and for any given material specimen, the best methods for extracting the form factor and the structure factor from the data need to be established. GIXS theory is reviewed here from the perspective of practical GIXS measurements and quantitative data analysis. In addition, schemes are discussed for the detailed analysis of GIXS data for the various self-assembled nanostructures of functional homopolymers, brush, star, and dendritic polymers, and block copolymers. Moreover, enhancements to the GIXS technique are discussed that can significantly improve its structure analysis by using the new synchrotron radiation sources such as third-generation X-ray sources with picosecond pulses and partial coherence and fourth-generation X-ray laser sources with femtosecond pulses and full coherence.

  12. Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles.

    PubMed

    Ha, Seungkyu; Janissen, Richard; Ussembayev, Yera Ye; van Oene, Maarten M; Solano, Belen; Dekker, Nynke H

    2016-05-19

    Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile TiO2 nanocylinders tethered with individual DNA molecules for use as force- and torque-transducers in an optical torque wrench. These developments provide the means for increased exploitation of the superior material properties of single-crystal TiO2 at the nanoscale.

  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

    2016-08-01

    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. PMID:27310879

  14. Correlating Nanostructures with Function: Structural Colors on the Wings of a Malaysian Bee

    NASA Astrophysics Data System (ADS)

    Matin, T. R.; Leong, M. K.; Majlis, B. Y.; Gebeshuber, I. C.

    2010-10-01

    Structural colours refer to colours generated by nanostructures, with the characteristic dimension of the structures on the wavelength of the visible light (i.e., some hundreds of nanometers). Examples for structural colours are the colours of CDs and DVDs, the colours of soap bubbles or oil films on water (thin films), or the colours of certain butterfly wings (e.g., photonic crystals). Recently, we located a Malaysian bee with iridescent structural coloration on its wings. The generation of the colouration is still unknown, and there is no respective scientific literature available. This study presents the first AFM experiments related to the structural coloration of the carpenter bee wing. First attempts to investigate the nanostructures of the wing were performed with non-contact atomic force microscopy (AFM, Park Systems XE-100), using a Silicon nitride cantilever with a spring constant of 40 N/m and a resonance frequency of 300.000 kHz. The AFM scans reveal three layers with structures with a diameter of several hundreds of nanometres. This, rules out thin films as the structures yielding the coloration. Future research and correlation of various structures with function in this bee wings will shed light on the contribution of these structures visible in the first AFM scans to the colouration. Structural colours produced by nature inspire novel approaches in man-made colours, via biomimetics (i.e., knowledge transfer from biology to technology).

  15. Contributions of Phenoxazone-Based Pigments to the Structure and Function of Nanostructured Granules in Squid Chromatophores.

    PubMed

    Williams, Thomas L; DiBona, Christopher W; Dinneen, Sean R; Labadie, Stephanie F Jones; Chu, Feixia; Deravi, Leila F

    2016-04-19

    Understanding the structure-function relationships of pigment-based nanostructures can provide insight into the molecular mechanisms behind biological signaling, camouflage, or communication experienced in many species. In squid Doryteuthis pealeii, combinations of phenoxazone-based pigments are identified as the source of visible color within the nanostructured granules that populate dermal chromatophore organs. In the absence of the pigments, granules experience a reduction in diameter with the loss of visible color, suggesting important structural and functional features. Energy gaps are estimated from electronic absorption spectra, revealing highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energies that are dependent upon the varying carboxylated states of the pigment. These results implicate a hierarchical mechanism for the bulk coloration in cephalopods originating from the molecular components confined within in the nanostructured granules of chromatophore organs. PMID:27049640

  16. Nanostructured materials for lithium-ion batteries: surface conductivity vs. bulk ion/electron transport.

    PubMed

    Ellis, B; Subramanya Herle, P; Rho, Y H; Nazar, L F; Dunlap, R; Perry, Laura K; Ryan, D H

    2007-01-01

    Lithium metal phosphates are amongst the most promising cathode materials for high capacity lithium-ion batteries. Owing to their inherently low electronic conductivity, it is essential to optimize their properties to minimize defect concentration and crystallite size (down to the submicron level), control morphology, and to decorate the crystallite surfaces with conductive nanostructures that act as conduits to deliver electrons to the bulk lattice. Here, we discuss factors relating to doping and defects in olivine phosphates LiMPO4 (M = Fe, Mn, Co, Ni) and describe methods by which in situ nanophase composites with conductivities ranging from 10(-4)-10(-2) S cm(-1) can be prepared. These utilize surface reactivity to produce intergranular nitrides, phosphides, and/or phosphocarbides at temperatures as low as 600 degrees C that maximize the accessibility of the bulk for Li de/insertion. Surface modification can only address the transport problem in part, however. A key issue in these materials is also to unravel the factors governing ion and electron transport within the lattice. Lithium de/insertion in the phosphates is accompanied by two-phase transitions owing to poor solubility of the single phase compositions, where low mobility of the phase boundary limits the rate characteristics. Here we discuss concerted mobility of the charge carriers. Using Mössbauer spectroscopy to pinpoint the temperature at which the solid solution forms, we directly probe small polaron hopping in the solid solution Li(x)FePO4 phases formed at elevated temperature, and give evidence for a strong correlation between electron and lithium delocalization events that suggests they are coupled.

  17. Nanostructures of LiBH4: a density-functional study.

    PubMed

    Vajeeston, P; Ravindran, P; Fjellvåg, H

    2009-07-01

    The phase stability and electronic structure of alpha- LiBH(4)-derived nanostructures and possible low energy surfaces of thin films have been investigated using the ab initio projected augmented plane wave method. Structural optimizations based on total energy calculations predicted that, for the alpha- LiBH(4) phase, the (010) surface is the most stable of the possible low-energy surfaces. The predicted critical sizes of the nano-cluster and nano-whisker for alpha- LiBH(4) are 1.75 and 1.5 nm, respectively. Similarly, the bond distances in the surfaces of a nano-whisker are found to be higher than that in the bulk material. The calculated hydrogen site energies suggest that it is relatively easier to remove hydrogen from the surface of the clusters and nano-whiskers than from bulk crystals.

  18. Functionalization of graphene oxide nanostructures improves photoluminescence and facilitates their use as optical probes in preclinical imaging.

    PubMed

    Prabhakar, Neeraj; Näreoja, Tuomas; von Haartman, Eva; Şen Karaman, Didem; Burikov, Sergey A; Dolenko, Tatiana A; Deguchi, Takahiro; Mamaeva, Veronika; Hänninen, Pekka E; Vlasov, Igor I; Shenderova, Olga A; Rosenholm, Jessica M

    2015-06-21

    Recently reported photoluminescent nanographene oxides (nGOs), i.e. nanographene oxidised with a sulfuric/nitric acid mixture (SNOx method), have tuneable photoluminescence and are scalable, simple and fast to produce optical probes. This material belongs to the vast class of photoluminescent carbon nanostructures, including carbon dots, nanodiamonds (NDs), graphene quantum dots (GQDs), all of which demonstrate a variety of properties that are attractive for biomedical imaging such as low toxicity and stable photoluminescence. In this study, the nGOs were organically surface-modified with poly(ethylene glycol)-poly(ethylene imine) (PEG-PEI) copolymers tagged with folic acid as the affinity ligand for cancer cells expressing folate receptors. The functionalization enhanced both the cellular uptake and quantum efficiency of the photoluminescence as compared to non-modified nGOs. The nGOs exhibited an excitation dependent photoluminescence that facilitated their detection with a wide range of microscope configurations. The functionalized nGOs were non-toxic, they were retained in the stained cell population over a period of 8 days and they were distributed equally between daughter cells. We have evaluated their applicability in in vitro and in vivo (chicken embryo CAM) models to visualize and track migratory cancer cells. The good biocompatibility and easy detection of the functionalized nGOs suggest that they could address the limitations faced with quantum dots and organic fluorophores in long-term in vivo biomedical imaging. PMID:25998585

  19. Functionalization of graphene oxide nanostructures improves photoluminescence and facilitates their use as optical probes in preclinical imaging.

    PubMed

    Prabhakar, Neeraj; Näreoja, Tuomas; von Haartman, Eva; Şen Karaman, Didem; Burikov, Sergey A; Dolenko, Tatiana A; Deguchi, Takahiro; Mamaeva, Veronika; Hänninen, Pekka E; Vlasov, Igor I; Shenderova, Olga A; Rosenholm, Jessica M

    2015-06-21

    Recently reported photoluminescent nanographene oxides (nGOs), i.e. nanographene oxidised with a sulfuric/nitric acid mixture (SNOx method), have tuneable photoluminescence and are scalable, simple and fast to produce optical probes. This material belongs to the vast class of photoluminescent carbon nanostructures, including carbon dots, nanodiamonds (NDs), graphene quantum dots (GQDs), all of which demonstrate a variety of properties that are attractive for biomedical imaging such as low toxicity and stable photoluminescence. In this study, the nGOs were organically surface-modified with poly(ethylene glycol)-poly(ethylene imine) (PEG-PEI) copolymers tagged with folic acid as the affinity ligand for cancer cells expressing folate receptors. The functionalization enhanced both the cellular uptake and quantum efficiency of the photoluminescence as compared to non-modified nGOs. The nGOs exhibited an excitation dependent photoluminescence that facilitated their detection with a wide range of microscope configurations. The functionalized nGOs were non-toxic, they were retained in the stained cell population over a period of 8 days and they were distributed equally between daughter cells. We have evaluated their applicability in in vitro and in vivo (chicken embryo CAM) models to visualize and track migratory cancer cells. The good biocompatibility and easy detection of the functionalized nGOs suggest that they could address the limitations faced with quantum dots and organic fluorophores in long-term in vivo biomedical imaging.

  20. Synthesis, structure and properties of hierarchical nanostructured porous materials studied by molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Chae, Kisung

    For applications of porous materials in many fields of technological importance, such as catalysis, filtration, separation, energy storage and conversion, the efficiency is often limited by chemical kinetics, and/or diffusion of reactants and products to and from the active sites. Hierarchical nanostructured porous materials (HNPMs) that possess both mesopores (2 nm < pore size < 50 nm) and micropores (pore size < 2 nm) have shown great potential for these applications as their bimodal porous structure can provide highly efficient mass transport through mesopores and high electrochemically accessible surface area from micropores. Despite extensive experimental studies, it remains a great challenge to quantify the synthesis-structure-properties relations in HNPMs due to the limitations of existing characterization tools and the difficulty in separating the sum of many effects in experiments. In this thesis work, we carried out a detailed study on the synthesis-structure-property relations in hierarchical nanostructured porous carbons (HNPCs) by using classical molecular dynamics (MD) simulations. We first developed a unique computational nanocasting approach in MD to mimic the synthesis of HNPCs with both mesopores from the templating and micropores from the direct quench of carbon source in MD. Mesoporous structure such as the pore size and the pore wall roughness as well as the microporous structure such as the density and the graphitic pore walls can be independently controlled by synthesis parameters, such as the size of the template, the interaction strength between the template and carbon source, the initial carbon density and the quench rate, respectively. These atomic models allowed us to quantify the structure-mechanical properties relation in aligned carbon nanotubes/amorphous porous carbon nanocomposites. Our study shows that there is an optimum balance between the crystallinity of CNTs and the number bridging bonds between CNTs and the microporous matrix

  1. Self-Assembly of Crystalline Structures of Magnetic Core-Shell Nanoparticles for Fabrication of Nanostructured Materials.

    PubMed

    Xue, Xiaozheng; Wang, Jianchao; Furlani, Edward P

    2015-10-14

    A theoretical study is presented of the template-assisted formation of crystalline superstructures of magnetic-dielectric core-shell particles. The templates produce highly localized gradient fields and a corresponding magnetic force that guides the assembly with nanoscale precision in particle placement. The process is studied using two distinct and complementary computational models that predict the dynamics and energy of the particles, respectively. Both mono- and polydisperse colloids are studied, and the analysis demonstrates for the first time that although the particles self-assemble into ordered crystalline superstructures, the particle formation is not unique. There is a Brownian motion-induced degeneracy in the process wherein various distinct, energetically comparable crystalline structures can form for a given template geometry. The models predict the formation of hexagonal close packed (HCP) and face centered cubic (FCC) structures as well as mixed phase structures due to in-plane stacking disorders, which is consistent with experimental observations. The polydisperse particle structures are less uniform than the monodisperse particle structures because of the irregular packing of different-sized particles. A comparison of self-assembly using soft- and hard-magnetic templates is also presented, the former being magnetized in a uniform field. This analysis shows that soft-magnetic templates enable an order-of-magnitude more rapid assembly and much higher spatial resolution in particle placement than their hard-magnetic counterparts. The self-assembly method discussed is versatile and broadly applies to arbitrary template geometries and multilayered and multifunctional mono- and polydisperse core-shell particles that have at least one magnetic component. As such, the method holds potential for the bottom-up fabrication of functional nanostructured materials for a broad range of applications. This work provides unprecedented insight into the assembly

  2. Self-Assembly of Crystalline Structures of Magnetic Core-Shell Nanoparticles for Fabrication of Nanostructured Materials.

    PubMed

    Xue, Xiaozheng; Wang, Jianchao; Furlani, Edward P

    2015-10-14

    A theoretical study is presented of the template-assisted formation of crystalline superstructures of magnetic-dielectric core-shell particles. The templates produce highly localized gradient fields and a corresponding magnetic force that guides the assembly with nanoscale precision in particle placement. The process is studied using two distinct and complementary computational models that predict the dynamics and energy of the particles, respectively. Both mono- and polydisperse colloids are studied, and the analysis demonstrates for the first time that although the particles self-assemble into ordered crystalline superstructures, the particle formation is not unique. There is a Brownian motion-induced degeneracy in the process wherein various distinct, energetically comparable crystalline structures can form for a given template geometry. The models predict the formation of hexagonal close packed (HCP) and face centered cubic (FCC) structures as well as mixed phase structures due to in-plane stacking disorders, which is consistent with experimental observations. The polydisperse particle structures are less uniform than the monodisperse particle structures because of the irregular packing of different-sized particles. A comparison of self-assembly using soft- and hard-magnetic templates is also presented, the former being magnetized in a uniform field. This analysis shows that soft-magnetic templates enable an order-of-magnitude more rapid assembly and much higher spatial resolution in particle placement than their hard-magnetic counterparts. The self-assembly method discussed is versatile and broadly applies to arbitrary template geometries and multilayered and multifunctional mono- and polydisperse core-shell particles that have at least one magnetic component. As such, the method holds potential for the bottom-up fabrication of functional nanostructured materials for a broad range of applications. This work provides unprecedented insight into the assembly

  3. Micropatterned nanostructures: a bioengineered approach to mass-produce functional myocardial grafts.

    PubMed

    Serpooshan, Vahid; Mahmoudi, Morteza

    2015-02-13

    Cell-based therapies are a recently established path for treating a wide range of human disease. Tissue engineering of contractile heart muscle for replacement therapy is among the most exciting and important of these efforts. However, current in vitro techniques of cultivating functional mature cardiac grafts have only been moderately successful due to the poor capability of traditional two-dimensional cell culture systems to recapitulate necessary in vivo conditions. In this issue, Kiefer et al introduce a laser-patterned nanostructured substrate (Al/Al2O3 nanowires) for efficient maintenance of oriented human cardiomyocytes, with great potential to open new roads to mass-production of contractile myocardial grafts for cardiovascular tissue engineering.

  4. Micropatterned nanostructures: a bioengineered approach to mass-produce functional myocardial grafts

    NASA Astrophysics Data System (ADS)

    Serpooshan, Vahid; Mahmoudi, Morteza

    2015-02-01

    Cell-based therapies are a recently established path for treating a wide range of human disease. Tissue engineering of contractile heart muscle for replacement therapy is among the most exciting and important of these efforts. However, current in vitro techniques of cultivating functional mature cardiac grafts have only been moderately successful due to the poor capability of traditional two-dimensional cell culture systems to recapitulate necessary in vivo conditions. In this issue, Kiefer et al [1] introduce a laser-patterned nanostructured substrate (Al/Al2O3 nanowires) for efficient maintenance of oriented human cardiomyocytes, with great potential to open new roads to mass-production of contractile myocardial grafts for cardiovascular tissue engineering.

  5. From small aromatic molecules to functional nanostructured carbon by pulsed laser-induced photochemical stitching

    NASA Astrophysics Data System (ADS)

    Gokhale, R. R.; Thakare, V. P.; Warule, S.; Lefez, B.; Hannoyer, B.; Jog, J. P.; Ogale, S. B.

    2012-06-01

    A novel route employing UV laser pulses (KrF Excimer, 248 nm) to cleave small aromatic molecules and stitch the generated free radicals into functional nanostructured forms of carbon is introduced. The process differs distinctly from any strategies wherein the aromatic rings are broken in the primary process. It is demonstrated that this pulsed laser-induced photochemical stitching (PLPS) process when applied to routine laboratory solvents (or toxic chemical wastes when discarded) Chlorobenzene and o-Dichlorobenzene yields Carbon Nanospheres (CNSs) comprising of graphene-like sheets assembled in onion-like configurations. This room temperature process implemented under normal laboratory conditions is versatile and clearly applicable to the whole family of haloaromatic compounds without and with additions of precursors or other nanomaterials. We further bring out its applicability for synthesis of metal-oxide based carbon nanocomposites.

  6. Effect of Dual-Function Nano-Structured Silicon Oxide Thin Film on Multi-Junction Solar Cells

    SciTech Connect

    Yan, B.; Sivec, L.; Yue, G.; Jiang, C. S.; Yang, J.; Guha, S.

    2011-01-01

    We present our recent study of using nano-structured hydrogenated silicon oxide films (nc-SiO{sub x}:H) as a dual-function layer in multi-junction solar cells. The nc-SiO{sub x}:H films were deposited using very high frequency glow discharge of a SiH{sub 4} (or Si{sub 2}H{sub 6}), CO{sub 2}, PH{sub 3}, and H{sub 2} gas mixture. By optimizing deposition parameters, we obtained 'dual function' nc-SiO{sub x}:H material characterized by a conductivity suitable for use as an n layer and optical properties suitable for use as an inter-reflection layer. We tested the nc-SiO{sub x}:H by replacing the normal n-type material in the tunnel junction of a multi-junction structure. The advantage of the dual-function nc-SiO{sub x}:H layer is twofold; one is to simplify the cell structure, and the other is to reduce any optical loss associated with the inter-reflection layer. Quantum efficiency measurements show the gain in top cell current is equal to or greater than the loss in bottom cell current for a-Si:H/nc-Si:H structures. In addition, a thinner a-Si:H top cell with the nc-SiO{sub x}:H n layer improves the top-cell stability, thereby providing higher stabilized solar cell efficiency. We also used the dual-function layer between the middle and the bottom cells in a-Si:H/a-SiGe:H/nc-Si:H triple-junction structures. The gain in the middle cell current is {approx}1.0 mA/cm{sup 2}, leading to an initial active-area efficiency of 14.8%.

  7. Nanoparticle Decorated Ultrathin Porous Nanosheets as Hierarchical Co3O4 Nanostructures for Lithium Ion Battery Anode Materials.

    PubMed

    Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong; Mølhave, Kristian; Liu, Yanguo; Zhao, Yanyan; Wang, Xun; Xu, Shengming; Zhu, Jing

    2016-02-05

    We report a facile synthesis of a novel cobalt oxide (Co3O4) hierarchical nanostructure, in which crystalline core-amorphous shell Co3O4 nanoparticles with a bimodal size distribution are uniformly dispersed on ultrathin Co3O4 nanosheets. When tested as anode materials for lithium ion batteries, the as-prepared Co3O4 hierarchical electrodes delivered high lithium storage properties comparing to the other Co3O4 nanostructures, including a high reversible capacity of 1053.1 mAhg(-1) after 50 cycles at a current density of 0.2 C (1 C = 890 mAg(-1)), good cycling stability and rate capability.

  8. Nanoparticle Decorated Ultrathin Porous Nanosheets as Hierarchical Co3O4 Nanostructures for Lithium Ion Battery Anode Materials

    PubMed Central

    Mujtaba, Jawayria; Sun, Hongyu; Huang, Guoyong; Mølhave, Kristian; Liu, Yanguo; Zhao, Yanyan; Wang, Xun; Xu, Shengming; Zhu, Jing

    2016-01-01

    We report a facile synthesis of a novel cobalt oxide (Co3O4) hierarchical nanostructure, in which crystalline core-amorphous shell Co3O4 nanoparticles with a bimodal size distribution are uniformly dispersed on ultrathin Co3O4 nanosheets. When tested as anode materials for lithium ion batteries, the as-prepared Co3O4 hierarchical electrodes delivered high lithium storage properties comparing to the other Co3O4 nanostructures, including a high reversible capacity of 1053.1 mAhg−1 after 50 cycles at a current density of 0.2 C (1 C = 890 mAg−1), good cycling stability and rate capability. PMID:26846434

  9. Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles

    NASA Astrophysics Data System (ADS)

    Ha, Seungkyu; Janissen, Richard; Ussembayev, Yera Ye.; van Oene, Maarten M.; Solano, Belen; Dekker, Nynke H.

    2016-05-01

    Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile TiO2 nanocylinders tethered with individual DNA molecules for use as force- and torque-transducers in an optical torque wrench. These developments provide the means for increased exploitation of the superior material properties of single-crystal TiO2 at the nanoscale.Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile

  10. A dual enzyme functionalized nanostructured thulium oxide based interface for biomedical application.

    PubMed

    Singh, Jay; Roychoudhury, Appan; Srivastava, Manish; Solanki, Pratima R; Lee, Dong Won; Lee, Seung Hee; Malhotra, B D

    2014-01-21

    In this paper, we present results of the studies related to fabrication of a rare earth metal oxide based efficient biosensor using an interface based on hydrothermally prepared nanostructured thulium oxide (n-Tm2O3). A colloidal solution of prepared nanorods has been electrophoretically deposited (EPD) onto an indium-tin-oxide (ITO) glass substrate. The n-Tm2O3 nanorods are found to provide improved sensing characteristics to the electrode interface in terms of electroactive surface area, diffusion coefficient, charge transfer rate constant and electron transfer kinetics. The structural and morphological studies of n-Tm2O3 nanorods have been carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopic techniques. This interfacial platform has been used for fabrication of a total cholesterol biosensor by immobilizing cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) onto a Tm2O3 nanostructured surface. The results of response studies of the fabricated ChEt-ChOx/n-Tm2O3/ITO bioelectrode show a broad linear range of 8-400 mg dL(-1), detection limit of 19.78 mg (dL cm(-2))(-1), and high sensitivity of 0.9245 μA (mg per dL cm(-2))(-1) with a response time of 40 s. Further, this bioelectrode has been utilized for estimation of total cholesterol with negligible interference (3%) from analytes present in human serum samples. The utilization of this n-Tm2O3 modified electrode for enzyme-based biosensor analysis offers an efficient strategy and a novel interface for application of the rare earth metal oxide materials in the field of electrochemical sensors and bioelectronic devices.

  11. Functionally graded materials: Design, processing and applications

    SciTech Connect

    Miyamoto, Y.; Kaysser, W.A.; Rabin, B.H.; Kawasaki, A.; Ford, R.G.

    1999-09-01

    In a Functionally Graded Material (FGM), the composition and structure gradually change over volume, resulting in corresponding changes in the properties of the material. By applying the many possibilities inherent in the FGM concept, it is anticipated that materials will be improved and new functions for them created. A comprehensive description of design, modeling, processing, and evaluation of FGMs as well as their applications is covered in this book. The contents include: lessons from nature; graded microstructures; modeling and design; characterization of properties; processing and fabrication; applications; and summary and outlook.

  12. Porous materials. Function-led design of new porous materials.

    PubMed

    Slater, Anna G; Cooper, Andrew I

    2015-05-29

    Porous solids are important as membranes, adsorbents, catalysts, and in other chemical applications. But for these materials to find greater use at an industrial scale, it is necessary to optimize multiple functions in addition to pore structure and surface area, such as stability, sorption kinetics, processability, mechanical properties, and thermal properties. Several different classes of porous solids exist, and there is no one-size-fits-all solution; it can therefore be challenging to choose the right type of porous material for a given job. Computational prediction of structure and properties has growing potential to complement experiment to identify the best porous materials for specific applications.

  13. Continuous spray forming of functionally gradient materials

    SciTech Connect

    McKechnie, T.N.; Richardson, E.H.

    1995-12-01

    Researchers at Plasma Processes Inc. have produced a Functional Gradient Material (FGM) through advanced vacuum plasma spray processing for high heat flux applications. Outlined in this paper are the manufacturing methods used to develop a four component functional gradient material of copper, tungsten, boron, and boron nitride. The FGM was formed with continuous gradients and integral cooling channels eliminating bondlines and providing direct heat transfer from the high temperature exposed surface to a cooling medium. Metallurgical and x-ray diffraction analyses of the materials formed through innovative VPS (vacuum plasma spray) processing are also presented. Applications for this functional gradient structural material range from fusion reactor plasma facing components to missile nose cones to boilers.

  14. Magnetic and transport properties of nanostructured materials and other novel systems

    NASA Astrophysics Data System (ADS)

    Bleiweiss, Michael Craig

    2001-07-01

    The structural, static magnetic and electrical transport properties of several novel and interesting systems were studied. The first system, a manganite class of ABO3 perovskites, appropriately doped with a divalent alkali (La1-xCaxMnO3), that exhibit colossal magnetoresistance (CMR). In addition to the typical high field negative magnetoresistance, an unusual low field positive magnetoresistance was discovered. Paramagnetic data, obtained via SQUID susceptometry, yield a Curie temperature of 277.2 K +/- 1.8 K. Transport properties show small polaron and double magnon effects in the temperature dependent resistivity, while the Hall coefficient was analyzed and found to possess both ordinary and anomalous components. The second group of substances was inverse opal structures or opal replicas with structure sizes on the order of 35 nm. Due to the three-dimensional nanostructuring, quantum effects were observed at temperatures far higher than have been previously reported. Fermi surface effects, namely deHaas-vanAlphen oscillations at 60 K, yield a net carrier concentration of 4 x 1018 carriers/cm3. One-dimensional weak localization (below 14 K), finite size effects, magnetic localization (up to 200 K), giant magnetoresistance (GMR) of more than 500% and both electron-like and hole-like Hall behaviors were also observed in the bismuth inverse opal samples. The carbon opal replicas, with n = 3.57 x 1022 carriers/cm3, show interesting effects such as one-dimensional variable range hopping (VRH) below 30 K, three-dimensional weak localization, Shubnikov-deHaas oscillations and quantum Hall effects (QHE). Never before have QHE been observed at such low fields (<2.5 T) and temperatures several times that of liquid helium (>30 K). The last material studied was magnesium diboride (MgB2). MgB 2 was doped with a variety of materials viz., Li, Bi, Cu, Zn and others. The addition of Li produced an increase in superconducting transition temperature approximately 1 K above that of

  15. Fabrication and application of advanced functional materials from lignincellulosic biomass

    NASA Astrophysics Data System (ADS)

    Hu, Sixiao

    This dissertation explored the conversion of lignocellulosic biomass into advanced functional materials and their potential applications. Lignocellulosic biomass represents an as-of-yet underutilized renewable source for not only biofuel production but also functional materials fabrication. This renewable source is a great alternative for fossil fuel based chemicals, which could be one of the solutions to energy crisis. In this work, it was demonstrated a variety of advanced materials including functional carbons, metal and silica nanoparticles could be derived from lignocellulosic biomass. Chapter 1 provided overall reviewed of the lignin structures, productions and its utilizations as plastics, absorbents and carbons, as well as the preparation of nano-structured silver, silica and silicon carbide/nitride from biomass. Chapter 2, 3 and 4 discussed the fabrication of highly porous carbons from isolated lignin, and their applications as electric supercapacitors for energy storage. In chapter 2, ultrafine porous carbon fibers were prepared via electrospinning followed by simultaneous carbonization and activation. Chapter 3 covered the fabrication of supercapacitor based on the porous carbon fibers and the investigation of their electrochemical performances. In chapter 4, porous carbon particulates with layered carbon nano plates structures were produced by simple oven-drying followed by simultaneous carbonization and activation. The effects of heat processing parameters on the resulting carbon structures and their electrochemical properties were discussed in details. Chapter 5 and 6 addressed the preparation of silver nanoparticles using lignin. Chapter 5 reported the synthesis, underlying kinetics and mechanism of monodispersed silver nanospheres with diameter less than 25 nm in aqueous solutions using lignin as dual reducing and capping agents. Chapter 6 covered the preparation of silver nanoparticles on electrospun celluloses ultrafine fibers using lignin as both

  16. Analysis of Advanced Thermoelectric Materials and Their Functional Limits

    NASA Technical Reports Server (NTRS)

    Kim, Hyun Jung

    2015-01-01

    The world's demand for energy is increasing dramatically, but the best energy conversion systems operate at approximately 30% efficiency. One way to decrease energy loss is in the recovery of waste heat using thermoelectric (TE) generators. A TE generator is device that generates electricity by exploiting heat flow across a thermal gradient. The efficiency of a TE material for power generation and cooling is determined by the dimensionless Figure of Merit (ZT): ZT = S(exp. 2)sigmaT/?: where S is the Seebeck coefficient, sigma is the electrical conductivity, T is the absolute temperature, and ? is the thermal conductivity. The parameters are not physically independent, but intrinsically coupled since they are a function of the transport properties of electrons. Traditional research on TE materials has focused on synthesizing bulk semiconductor-type materials that have low thermal conductivity and high electrical conductivity affording ZT values of 1. The optimization of the s/? ratio is difficult to achieve using current material formats, as these material constants are complementary. Recent areas of research are focusing on using nanostructural artifacts that introduce specific dislocations and boundary conditions that scatter the phonons. This disrupts the physical link between thermal (phonon) and electrical (electron) transport. The result is that ? is decreased without decreasing s. These material formats give ZT values of up to 2 which represent approximately 18% energy gain from waste heat recovery. The next challenge in developing the next generation of TE materials with superior performance is to tailor the interconnected thermoelectric physical parameters of the material system. In order to approach this problem, the fundamental physics of each parameter S, sigma, and ? need to be physically understood in their context of electron/phonon interaction for the construction of new high ZT thermoelectric devices. Is it possible to overcome the physical limit

  17. Ultimate Osmosis Engineered by the Pore Geometry and Functionalization of Carbon Nanostructures

    PubMed Central

    Song, Zhigong; Xu, Zhiping

    2015-01-01

    Osmosis is the key process in establishing versatile functions of cellular systems and enabling clean-water harvesting technologies. Membranes with single-atom thickness not only hold great promises in approaching the ultimate limit of these functions, but also offer an ideal test-bed to explore the underlying physical mechanisms. In this work, we explore diffusive and osmotic transport of water and ions through carbon nanotube and porous graphene based membranes by performing molecular dynamics simulations. Our comparative study shows that the cylindrical confinement in carbon nanotubes offers much higher salt rejection at similar permeability in osmosis compared to porous graphene. Moreover, chemical functionalization of the pores modulates the membrane performance by its steric and electrostatic nature, especially at small-size pores due to the fact that the optimal transport is achieved by ordered water transport near pore edges. These findings lay the ground for the ultimate design of forward osmosis membranes with optimized performance trade-off, given the capability of nano-engineering nanostructures by their geometry and chemistry. PMID:26037602

  18. Relationship between material properties and transparent heater performance for both bulk-like and percolative nanostructured networks.

    PubMed

    Sorel, Sophie; Bellet, Daniel; Coleman, Jonathan N

    2014-05-27

    Transparent heaters are important for many applications and in the future are likely to be fabricated from thin, conducting, nanostructured networks. However, the electrical properties of such networks are almost always controlled by percolative effects. The impact of percolation on heating effects has not been considered, and the material parameter combinations that lead to efficient performance are not known. In fact, figures of merit for transparent heaters have not been elucidated, either in bulk-like or percolative systems. Here, we develop a simple yet comprehensive model describing the operation of transparent heaters. By considering the balance of Joule heating versus power dissipated by both convection and radiation, we derive an expression for the time-dependent heater temperature as a function of both electrical and thermal parameters. This equation can be modified to describe the relationship between temperature, optical transmittance, and electrical/thermal parameters in both bulk-like and percolative systems. By performing experiments on silver nanowire networks, systems known to display both bulk-like and percolative regimes, we show the model to describe real systems extremely well. This work shows the performance of transparent heaters in the percolative regime to be significantly less efficient compared to the bulk-like regime, implying the diameter of the nanowires making up the network to be critical. The model allows the identification of figures of merit for networks in both bulk-like and percolative regimes. We show that metallic nanowire networks are most promising, closely followed by CVD graphene, with networks of solution-processed graphene and carbon nanotubes being much less efficient. PMID:24694252

  19. Cellular interactions and stimulated biological functions mediated by nanostructured carbon for tissue reconstruction and tracheal tubes and sutures.

    PubMed

    Misra, R D K; Chaudhari, P M

    2013-02-01

    Nylon 6,6 is used for biological applications including gastrointestinal segments, tracheal tubes and sutures, vascular graft, and for hard tissue reconstruction. While it is a relatively inexpensive polymer, it is not widely acceptable as a preferred biomaterial because of bioactivity. To this end, we have discovered the exciting evidence that introduction of a novel nanostructured carbon, graphene, in the void space between the nylon chains and processing at elevated pressure favorably stimulates cellular functions and provides high degree of cytocompatibility. The cell-substrate interactions on stand alone Nylon 6,6 and Nylon 6,6-graphene oxide hybrid system were investigated in terms of cell attachment, viability, proliferation, and assessment of proteins, actin, vinculin, and fibronectin. The enhanced biological functions in the nanostructured hybrid system are attributed to relatively superior hydrophilicity of the surface and to the presence of graphene. Furthermore, it is proposed that the negatively charged graphene interacts with the polar nature of cells and the culture medium, such that the interaction is promoted through polar forces. This is accomplished by investigating cell attachment, proliferation, and morphology, including cytomorphometry evaluation, and quantitative assessment of prominent proteins, actin, vinculin, and fibronectin that are sensitive to cell-substrate interactions. Osteoblasts were studied to establish the practical viability of the hybrid nanostructured biomaterial. The study strengthens the foundation for utilizing nano- or quantum-size effects of nanostructured biomaterials.

  20. Dental implants from functionally graded materials.

    PubMed

    Mehrali, Mehdi; Shirazi, Farid Seyed; Mehrali, Mohammad; Metselaar, Hendrik Simon Cornelis; Kadri, Nahrizul Adib Bin; Osman, Noor Azuan Abu

    2013-10-01

    Functionally graded material (FGM) is a heterogeneous composite material including a number of constituents that exhibit a compositional gradient from one surface of the material to the other subsequently, resulting in a material with continuously varying properties in the thickness direction. FGMs are gaining attention for biomedical applications, especially for implants, owing to their reported superior composition. Dental implants can be functionally graded to create an optimized mechanical behavior and achieve the intended biocompatibility and osseointegration improvement. This review presents a comprehensive summary of biomaterials and manufacturing techniques researchers employ throughout the world. Generally, FGM and FGM porous biomaterials are more difficult to fabricate than uniform or homogenous biomaterials. Therefore, our discussion is intended to give the readers about successful and obstacles fabrication of FGM and porous FGM in dental implants that will bring state-of-the-art technology to the bedside and develop quality of life and present standards of care.

  1. Electrostatic interactions for directed assembly of high performance nanostructured energetic materials of Al/Fe2O3/multi-walled carbon nanotube (MWCNT)

    NASA Astrophysics Data System (ADS)

    Zhang, Tianfu; Ma, Zhuang; Li, Guoping; Wang, Zhen; Zhao, Benbo; Luo, Yunjun

    2016-05-01

    Electrostatic self-assembly in organic solvent without intensively oxidative or corrosive environments, was adopted to prepare Al/Fe2O3/MWCNT nanostructured energetic materials as an energy generating material. The negatively charged MWCNT was used as a glue-like agent to direct the self-assembly of the well dispersed positively charged Al (fuel) and Fe2O3 (oxide) nanoparticles. This spontaneous assembly method without any surfactant chemistry or other chemical and biological moieties decreased the aggregation of the same nanoparticles largely, moreover, the poor interfacial contact between the Al (fuel) and Fe2O3 (oxide) nanoparticles was improved significantly, which was the key characteristic of high performance nanostructured energetic materials. In addition, the assembly process was confirmed as Diffusion-Limited Aggregation. The assembled Al/Fe2O3/MWCNT nanostructured energetic materials showed excellent performance with heat release of 2400 J/g, peak pressure of 0.42 MPa and pressurization rate of 105.71 MPa/s, superior to that in the control group Al/Fe2O3 nanostructured energetic materials prepared by sonication with heat release of 1326 J/g, peak pressure of 0.19 MPa and pressurization rate of 33.33 MPa/s. Therefore, the approach, which is facile, opens a promising route to the high performance nanostructured energetic materials.

  2. The ``Missing Compounds'' affair in functionality-driven material discovery

    NASA Astrophysics Data System (ADS)

    Zunger, Alex

    2014-03-01

    In the paradigm of ``data-driven discovery,'' underlying one of the leading streams of the Material Genome Initiative (MGI), one attempts to compute high-throughput style as many of the properties of as many of the N (about 10**5- 10**6) compounds listed in databases of previously known compounds. One then inspects the ensuing Big Data, searching for useful trends. The alternative and complimentary paradigm of ``functionality-directed search and optimization'' used here, searches instead for the n much smaller than N configurations and compositions that have the desired value of the target functionality. Examples include the use of genetic and other search methods that optimize the structure or identity of atoms on lattice sites, using atomistic electronic structure (such as first-principles) approaches in search of a given electronic property. This addresses a few of the bottlenecks that have faced the alternative, data-driven/high throughput/Big Data philosophy: (i) When the configuration space is theoretically of infinite size, building a complete data base as in data-driven discovery is impossible, yet searching for the optimum functionality, is still a well-posed problem. (ii) The configuration space that we explore might include artificially grown, kinetically stabilized systems (such as 2D layer stacks; superlattices; colloidal nanostructures; Fullerenes) that are not listed in compound databases (used by data-driven approaches), (iii) a large fraction of chemically plausible compounds have not been experimentally synthesized, so in the data-driven approach these are often skipped. In our approach we search explicitly for such ``Missing Compounds''. It is likely that many interesting material properties will be found in cases (i)-(iii) that elude high throughput searches based on databases encapsulating existing knowledge. I will illustrate (a) Functionality-driven discovery of topological insulators and valley-split quantum-computer semiconductors, as well

  3. Design and functionality of colloidal-crystal-templated materials--chemical applications of inverse opals.

    PubMed

    Stein, Andreas; Wilson, Benjamin E; Rudisill, Stephen G

    2013-04-01

    Templating with colloidal crystals composed of monodisperse spheres is a convenient chemical method to obtain porous materials with well-ordered periodicity and interconnected pore systems. The three-dimensionally ordered macroporous (3DOM) products or inverse opals are of interest for numerous applications, both for the optical properties related to structural color of these photonic crystal materials and because of their bicontinuous nanostructure, i.e., a continuous nanostructured skeleton with large interfacial area and a three-dimensionally interconnected pore system with low tortuosity. This review outlines various synthetic methods used to control the morphology of 3DOM materials with different compositions. It highlights aspects of the choice of colloidal particles, assembly of the colloidal crystal template, infiltration and processing, template removal, and other necessary modifications to enhance the functionality of the materials. It also considers syntheses within the confinement of 3DOM materials and summarizes characterization methods that are particularly useful in the analysis of 3DOM materials. The review then discusses chemical applications of 3DOM materials, namely sorption and controlled release, optical and electrochemical sensors, solar cells, lithium ion batteries, supercapacitors, fuel cells, and environmental and chemical fuel catalysis. A focus is on structural features and materials properties that enable these applications. PMID:23079696

  4. Design and functionality of colloidal-crystal-templated materials--chemical applications of inverse opals.

    PubMed

    Stein, Andreas; Wilson, Benjamin E; Rudisill, Stephen G

    2013-04-01

    Templating with colloidal crystals composed of monodisperse spheres is a convenient chemical method to obtain porous materials with well-ordered periodicity and interconnected pore systems. The three-dimensionally ordered macroporous (3DOM) products or inverse opals are of interest for numerous applications, both for the optical properties related to structural color of these photonic crystal materials and because of their bicontinuous nanostructure, i.e., a continuous nanostructured skeleton with large interfacial area and a three-dimensionally interconnected pore system with low tortuosity. This review outlines various synthetic methods used to control the morphology of 3DOM materials with different compositions. It highlights aspects of the choice of colloidal particles, assembly of the colloidal crystal template, infiltration and processing, template removal, and other necessary modifications to enhance the functionality of the materials. It also considers syntheses within the confinement of 3DOM materials and summarizes characterization methods that are particularly useful in the analysis of 3DOM materials. The review then discusses chemical applications of 3DOM materials, namely sorption and controlled release, optical and electrochemical sensors, solar cells, lithium ion batteries, supercapacitors, fuel cells, and environmental and chemical fuel catalysis. A focus is on structural features and materials properties that enable these applications.

  5. Fracture Analysis of Functionally Graded Materials

    SciTech Connect

    Zhang, Ch.; Gao, X. W.; Sladek, J.; Sladek, V.

    2010-05-21

    This paper reports our recent research works on crack analysis in continuously non-homogeneous and linear elastic functionally graded materials. A meshless boundary element method is developed for this purpose. Numerical examples are presented and discussed to demonstrate the efficiency and the accuracy of the present numerical method, and to show the effects of the material gradation on the crack-opening-displacements and the stress intensity factors.

  6. Enhanced photon absorption in spiral nanostructured solar cells using layered 2D materials.

    PubMed

    Tahersima, Mohammad H; Sorger, Volker J

    2015-08-28

    Recent investigations of semiconducting two-dimensional (2D) transition metal dichalcogenides have provided evidence for strong light absorption relative to its thickness attributed to high density of states. Stacking a combination of metallic, insulating, and semiconducting 2D materials enables functional devices with atomic thicknesses. While photovoltaic cells based on 2D materials have been demonstrated, the reported absorption is still just a few percent of the incident light due to their sub-wavelength thickness leading to low cell efficiencies. Here we show that taking advantage of the mechanical flexibility of 2D materials by rolling a molybdenum disulfide (MoS(2))/graphene (Gr)/hexagonal boron nitride stack to a spiral solar cell allows for optical absorption up to 90%. The optical absorption of a 1 μm long hetero-material spiral cell consisting of the aforementioned hetero stack is about 50% stronger compared to a planar MoS(2) cell of the same thickness; although the volumetric absorbing material ratio is only 6%. A core-shell structure exhibits enhanced absorption and pronounced absorption peaks with respect to a spiral structure without metallic contacts. We anticipate these results to provide guidance for photonic structures that take advantage of the unique properties of 2D materials in solar energy conversion applications.

  7. Boosting electrical conductivity in a gel-derived material by nanostructuring with trace carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Canevet, David; Pérez Del Pino, Angel; Amabilino, David B.; Sallé, Marc

    2011-07-01

    An organogelator with two distinct π-functional units is able to incorporate carbon nanotubes into its mesh of fibres in the gel state. The morphology of the material derived from this nanocomposite after evaporation of the solvent is a complex mesh of fibres which is clearly different from the pure gelator. This feature indicates a role of the nanotubes in assisting the formation of a fibre structure in the gel thanks to their interaction with the pyrene units in the organogelator. The nanocomposite conducts electricity once the p-type gelator is doped with iodine vapour. The change in morphology caused by the carbon material increases the conductivity of the material compared with the purely organic conducting system. It is remarkable that this improvement in the physical property is caused by an extremely small proportion of the carbon material (only present at a ratio of 0.1% w/w). The practically unique properties of TTF unit allow measurements with both doped and undoped materials with conducting atomic force microscopy which have demonstrated that the carbon nanotubes are not directly responsible for the increased conductivity.An organogelator with two distinct π-functional units is able to incorporate carbon nanotubes into its mesh of fibres in the gel state. The morphology of the material derived from this nanocomposite after evaporation of the solvent is a complex mesh of fibres which is clearly different from the pure gelator. This feature indicates a role of the nanotubes in assisting the formation of a fibre structure in the gel thanks to their interaction with the pyrene units in the organogelator. The nanocomposite conducts electricity once the p-type gelator is doped with iodine vapour. The change in morphology caused by the carbon material increases the conductivity of the material compared with the purely organic conducting system. It is remarkable that this improvement in the physical property is caused by an extremely small proportion of the

  8. Al-doped ZnO Nanostructured Thin Films: Density Functional Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Sarma, J. V. N.; Rahman, A.; Jayaganthan, R.; Chowdhury, Rajib; Haranath, D.

    2015-06-01

    Nanostructured Al-doped ZnO (AZO) films are deposited on glass substrates by electroless deposition technique in the present work. AZO films with Al concentration from 1 at.% to 5 at.% are investigated for their structural and morphological properties by X-ray diffraction (XRD), and atomic force microscopy (AFM). An excellent homogeneity is achieved with average crystallite sizes of below 32 nm and a nearly constant root mean square (RMS) surface roughness between 1 nm and 3 nm, for various Al doping concentrations. These smooth and uniform films are characterized for their optical and photoluminescence (PL) properties. A higher value of average transparency between 79% and 92% in the wavelength range of 300-800 nm is achieved, and the PL intensity is found to be a strong function of doping. Density functional theory (DFT) calculations agree with the measured transmittance values, in addition to their predicted electronic structure. Moreover, time-resolved PL measurements indicate that the luminescence decay time decreases with increased doping concentration.

  9. Acoustoplasma synthesis of nanoparticles of metal oxides and formation of nanostructured coatings on material surfaces under ultrasonic treatment

    NASA Astrophysics Data System (ADS)

    Bulychev, N. A.; Morozova, E. A.; Muravyev, E. N.; Chernov, A. A.; Kazaryan, M. A.

    2015-12-01

    In this paper, a new form of plasma discharge in a liquid under intensive ultrasonic treatment exceeding the cavitation threshold has been explored in view of initiation of various physical and chemical processes. Furthermore, in this plasma discharge, nanoparticles of oxides of various metals with controlled shape and size of particles and narrow particles size distribution have been synthesized. Further research proved that ultrasonic cavitation during synthesis significantly affects the physical and chemical characteristics of nanoparticles. These nanoparticles can be used for formation of nanostructured coatings on surfaces of various materials by an ultrasonic technique.

  10. Synthesis of nanostructured materials based on YBa2Cu3O7_y and BiFeO3

    NASA Astrophysics Data System (ADS)

    Palchaev, D. K.; Murlieva, Zh Kh; Rabadanov, M. H.; Gadzhimagomedov, S. Kh; M-R Alikhanov, N.; Emirov, R. M.; Asvarov, A. S.

    2016-09-01

    Methods for creating new nanostructured materials based on YBa2Cu3O7-δ and BiFeO3, results of a study of their structure, morphology and electrical properties are present. Morphology studies show that the micron-sized grains of ceramics are agglomerates of nanoparticles of about 50 nm average size for both BiFeO3 and YBa2Cu3O7-y. These nanoparticles are responsible for weak ferromagnetism in bismuth ferrite, and for increase of the critical temperature up to 96 K in YBa2Cu3O7-δ nanoceramics.

  11. Alternative nanostructures for thermophones.

    PubMed

    Aliev, Ali E; Mayo, Nathanael K; Jung de Andrade, Monica; Robles, Raquel O; Fang, Shaoli; Baughman, Ray H; Zhang, Mei; Chen, Yongsheng; Lee, Jae Ah; Kim, Seon Jeong

    2015-05-26

    Thermophones are highly promising for applications such as high-power SONAR arrays, flexible loudspeakers, and noise cancellation devices. So far, freestanding carbon nanotube aerogel sheets provide the most attractive performance as a thermoacoustic heat source. However, the limited accessibility of large-size freestanding carbon nanotube aerogel sheets and other even more exotic materials recently investigated hampers the field. We describe alternative materials for a thermoacoustic heat source with high-energy conversion efficiency, additional functionalities, environmentally friendly, and cost-effective production technologies. We discuss the thermoacoustic performance of alternative nanostructured materials and compare their spectral and power dependencies of sound pressure in air. We demonstrate that the heat capacity of aerogel-like nanostructures can be extracted by a thorough analysis of the sound pressure spectra. The study presented here focuses on engineering thermal gradients in the vicinity of nanostructures and subsequent heat dissipation processes from the interior of encapsulated thermoacoustic projectors. Applications of thermoacoustic projectors for high-power SONAR arrays, sound cancellation, and optimal thermal design, regarding enhanced energy conversion efficiency, are discussed.

  12. 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.

  13. Functionalization of graphene oxide nanostructures improves photoluminescence and facilitates their use as optical probes in preclinical imaging

    NASA Astrophysics Data System (ADS)

    Prabhakar, Neeraj; Näreoja, Tuomas; von Haartman, Eva; Şen Karaman, Didem; Burikov, Sergey A.; Dolenko, Tatiana A.; Deguchi, Takahiro; Mamaeva, Veronika; Hänninen, Pekka E.; Vlasov, Igor I.; Shenderova, Olga A.; Rosenholm, Jessica M.

    2015-06-01

    Recently reported photoluminescent nanographene oxides (nGOs), i.e. nanographene oxidised with a sulfuric/nitric acid mixture (SNOx method), have tuneable photoluminescence and are scalable, simple and fast to produce optical probes. This material belongs to the vast class of photoluminescent carbon nanostructures, including carbon dots, nanodiamonds (NDs), graphene quantum dots (GQDs), all of which demonstrate a variety of properties that are attractive for biomedical imaging such as low toxicity and stable photoluminescence. In this study, the nGOs were organically surface-modified with poly(ethylene glycol)-poly(ethylene imine) (PEG-PEI) copolymers tagged with folic acid as the affinity ligand for cancer cells expressing folate receptors. The functionalization enhanced both the cellular uptake and quantum efficiency of the photoluminescence as compared to non-modified nGOs. The nGOs exhibited an excitation dependent photoluminescence that facilitated their detection with a wide range of microscope configurations. The functionalized nGOs were non-toxic, they were retained in the stained cell population over a period of 8 days and they were distributed equally between daughter cells. We have evaluated their applicability in in vitro and in vivo (chicken embryo CAM) models to visualize and track migratory cancer cells. The good biocompatibility and easy detection of the functionalized nGOs suggest that they could address the limitations faced with quantum dots and organic fluorophores in long-term in vivo biomedical imaging.Recently reported photoluminescent nanographene oxides (nGOs), i.e. nanographene oxidised with a sulfuric/nitric acid mixture (SNOx method), have tuneable photoluminescence and are scalable, simple and fast to produce optical probes. This material belongs to the vast class of photoluminescent carbon nanostructures, including carbon dots, nanodiamonds (NDs), graphene quantum dots (GQDs), all of which demonstrate a variety of properties that are

  14. Structural and functional biological materials: Abalone nacre, sharp materials, and abalone foot adhesion

    NASA Astrophysics Data System (ADS)

    Lin, Albert Yu-Min

    A three-part study of lessons from nature is presented through the examination of various biological materials, with an emphasis on materials from the mollusk Haliotis rufescens, commonly referred to as the red abalone. The three categories presented are: structural hierarchy, self-assembly, and functionality. Ocean mollusk shells are composed of aragonite/calcite crystals interleaved with layers of a visco-elastic protein, having dense, tailored structures with excellent mechanical properties. The complex nano-laminate structure of this bio-composite material is characterized and related to its mechanical properties. Three levels of structural hierarchy are identified: macroscale mesolayers separating larger regions of tiled aragonite, microscale organization of 0.5 mum by 10 mum aragonite bricks; nanoscale mineral bridges passing through 30 nm layers of organic matrix separating individual aragonite tiles. Composition and growth mechanisms of this nanostructure were observed through close examination of laboratory-grown samples using scanning electron microscopy (SEM), Raman spectroscopy, and transmission electron microscopy (TEM). Glass slides and nacre pucks were implanted onto the growth surface of living abalone and removed periodically to observe trends in nacre deposition. Various deproteinization and demineralization experiments are used to explore the inorganic and organic components of the nacre's structure. The organic component of the shell is characterized by atomic force microscopy (AFM). The functionality of various biological materials is described and investigated. Two specific types of functionality are characterized, the ability of some materials to cut and puncture through sharp designs, and the ability for some materials to be used as attachment devices. Aspects of cutting materials employed by a broad range of animals were characterized and compared. In respect to the attachment mechanisms the foot of the abalone and the tree frog were

  15. Microwave-assisted Synthesis and Biomedical Applications of Inorganic Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Jia, Juncai

    Inorganic nanostrucured materials have attracted much attention owing to their unique features and important applications in biomedicine. This thesis describes the development of rapid and efficient approaches to synthesize inorganic nanostructures, and introduces some potential applications. Magnetic nanostructures, such as necklace-like FeNi3 magnetic nanochains and magnetite nanoclusters, were synthesized by an efficient microwave-hydrothermal process. They were used as magnetic resonance imaging (MRI) contrast agents. Magnetic FeNi3 nanochains were synthesized by reducing iron(III) acetylacetonate and nickel(II) acetylacetonate with hydrazine in ethylene glycol solution without any template under microwave irradiation. This was a rapid and economical route based on an efficient microwave-hydrothermal process which significantly shortened the synthesis time to mins. The morphologies and size of the materials could be effectively controlled by adjusting the reaction conditions, such as, the reaction time, temperature and concentrations of reactants. The morphology and composition of the as-prepared products were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The size of the aligned nanospheres in the magnetic FeNi 3 chains could be adjusted from 150nm to 550nm by increasing the amounts of the precursors. Magnetic measurements revealed that the FeNi3 nanochains showed enhanced coercivity and saturation magnetization. Toxicity tests by exposure of FeNi3 nanochains to the zebrafish larvae showed that the as-prepared nanochains were biocompatible. In vitro magnetic resonance imaging (MRI) confirms the effectiveness of the FeNi 3 nanochains as sensitive MRI probes. Magnetite nanoclusters were synthesized by reducing iron(III) acetylacetonate with hydrazine in ethylene glycol under microwave irradiation. The nanoclusters showed enhanced T2

  16. 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

  17. Nanostructured materials in drug and gene delivery: a review of the state of the art.

    PubMed

    Petkar, Kailash C; Chavhan, Sandip S; Agatonovik-Kustrin, Snezana; Sawant, Krutika K

    2011-01-01

    A wide variety of drug delivery systems have been developed, each with its own advantages and limitations, but the important goals of all of the systems are to enhance bioavailability, reduce drug toxicity, target to a particular organ, and increase the stability of the drug. The development of nanostructured drug carriers have grasped increased attention from scientific and commercial organizations due to their unique ability to deliver drugs and challenging molecules such as proteins and nucleic acids. These carriers present many technological advantages such as high carrier capacity, high chemical and biological stability, feasibility of incorporating both hydrophilic and hydrophobic substances, and their ability to be administered by a variety of routes (including oral, inhalational, and parenteral) to provide controlled/sustained drug release. Moreover, applications of nanoparticulate formulations in enhancing drug solubility, dissolution, bioavailability, safety, and stability have already been proven. In the view of their multifaceted applications, the present review aims to discuss and summarize some of the interesting findings and applications, methods of preparation, and characterization of various nanostructured carriers useful in drug delivery. Included in this discussion are polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, dendrimers, cyclodextrins, fullerenes, gold and silica nanoparticles, and quantum dots. Because there are likely to be new applications for nanoparticles in drug delivery, they are expected to solve many problems associated with the delivery of drugs and biomolecules through different delivery routes. PMID:21663574

  18. Electrodeposited manganese dioxide nanostructures on electro-etched carbon fibers: High performance materials for supercapacitor applications

    SciTech Connect

    Kazemi, Sayed Habib; Maghami, Mostafa Ghaem; Kiani, Mohammad Ali

    2014-12-15

    Highlights: • We report a facile method for fabrication of MnO{sub 2} nanostructures on electro-etched carbon fiber. • MnO{sub 2}-ECF electrode shows outstanding supercapacitive behavior even at high discharge rates. • Exceptional cycle stability was achieved for MnO{sub 2}-ECF electrode. • The coulombic efficiency of MnO{sub 2}-ECF electrode is nearly 100%. - Abstract: In this article we introduce a facile, low cost and additive/template free method to fabricate high-rate electrochemical capacitors. Manganese oxide nanostructures were electrodeposited on electro-etched carbon fiber substrate by applying a constant anodic current. Nanostructured MnO{sub 2} on electro-etched carbon fiber was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis. The electrochemical behavior of MnO{sub 2} electro-etched carbon fiber electrode was investigated by electrochemical techniques including cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. A maximum specific capacitance of 728.5 F g{sup −1} was achieved at a scan rate of 5 mV s{sup −1} for MnO{sub 2} electro-etched carbon fiber electrode. Also, this electrode showed exceptional cycle stability, suggesting that it can be considered as a good candidate for supercapacitor electrodes.

  19. Integration of MEMS with nanostructured metal-oxide materials for improved sensors for volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Chandra, Sudhir; Pandya, Hardik; Vyas, Anoop

    2012-10-01

    The primary aim of the present work is to lower the operating temperature of the metal-oxide based sensors for detection of volatile organic compounds (VOCs) without compromising the sensitivity of the device. For this purpose, nanostructured oxides of ITO, Cu and Zn have been explored. The oxides of Cu and Zn have been synthesized by a novel process of thermal oxidation of the respective metal layers in air ambient without using any seed or catalyst layer. On the other hand, nanostructured ITO was obtained by RF magnetron sputtering process. For the heating of the sensing layer, a Ni microheater has been integrated on the sensor chip. Micro-electro-mechanical Systems (MEMS) technology has been adopted for the fabrication of the complete sensor for achieving the desired operating temperature at reduced power level. The sensor was extensively tested for a variety of VOCs such as acetone, methanol, ethanol and IPA. The issues involved in integrating nanostructured oxides with MEMS technology are also addressed.

  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. Nanostructured Aptamer-Functionalized Black Phosphorus Sensing Platform for Label-Free Detection of Myoglobin, a Cardiovascular Disease Biomarker.

    PubMed

    Kumar, Vinod; Brent, Jack R; Shorie, Munish; Kaur, Harmanjit; Chadha, Gaganpreet; Thomas, Andrew G; Lewis, Edward A; Rooney, Aidan P; Nguyen, Lan; Zhong, Xiang Li; Burke, M Grace; Haigh, Sarah J; Walton, Alex; McNaughter, Paul D; Tedstone, Aleksander A; Savjani, Nicky; Muryn, Christopher A; O'Brien, Paul; Ganguli, Ashok K; Lewis, David J; Sabherwal, Priyanka

    2016-09-01

    We report the electrochemical detection of the redox active cardiac biomarker myoglobin (Mb) using aptamer-functionalized black phosphorus nanostructured electrodes by measuring direct electron transfer. The as-synthesized few-layer black phosphorus nanosheets have been functionalized with poly-l-lysine (PLL) to facilitate binding with generated anti-Mb DNA aptamers on nanostructured electrodes. This aptasensor platform has a record-low detection limit (∼0.524 pg mL(-1)) and sensitivity (36 μA pg(-1) mL cm(-2)) toward Mb with a dynamic response range from 1 pg mL(-1) to 16 μg mL(-1) for Mb in serum samples. This strategy opens up avenues to bedside technologies for multiplexed diagnosis of cardiovascular diseases in complex human samples.

  2. Nanostructured Aptamer-Functionalized Black Phosphorus Sensing Platform for Label-Free Detection of Myoglobin, a Cardiovascular Disease Biomarker.

    PubMed

    Kumar, Vinod; Brent, Jack R; Shorie, Munish; Kaur, Harmanjit; Chadha, Gaganpreet; Thomas, Andrew G; Lewis, Edward A; Rooney, Aidan P; Nguyen, Lan; Zhong, Xiang Li; Burke, M Grace; Haigh, Sarah J; Walton, Alex; McNaughter, Paul D; Tedstone, Aleksander A; Savjani, Nicky; Muryn, Christopher A; O'Brien, Paul; Ganguli, Ashok K; Lewis, David J; Sabherwal, Priyanka

    2016-09-01

    We report the electrochemical detection of the redox active cardiac biomarker myoglobin (Mb) using aptamer-functionalized black phosphorus nanostructured electrodes by measuring direct electron transfer. The as-synthesized few-layer black phosphorus nanosheets have been functionalized with poly-l-lysine (PLL) to facilitate binding with generated anti-Mb DNA aptamers on nanostructured electrodes. This aptasensor platform has a record-low detection limit (∼0.524 pg mL(-1)) and sensitivity (36 μA pg(-1) mL cm(-2)) toward Mb with a dynamic response range from 1 pg mL(-1) to 16 μg mL(-1) for Mb in serum samples. This strategy opens up avenues to bedside technologies for multiplexed diagnosis of cardiovascular diseases in complex human samples. PMID:27508925

  3. Thermally Induced Shape Modification of Free-standing Nanostructures for Advanced Functionalities

    NASA Astrophysics Data System (ADS)

    Cui, Ajuan; Li, Wuxia; Shen, Tiehan H.; Yao, Yuan; Fenton, J. C.; Peng, Yong; Liu, Zhe; Zhang, Junwei; Gu, Changzhi

    2013-08-01

    Shape manipulation of nanowires is highly desirable in the construction of nanostructures, in producing free-standing interconnect bridges and as a building block of more complex functional structures. By introducing asymmetry in growth parameters, which may result in compositional or microstructural non-uniformity in the nanowires, thermal annealing can be used to induce shape modification of free-standing nanowires. We demonstrate that such manipulation is readily achieved using vertically grown Pt-Ga-C composite nanowires fabricated by focused-ion-beam induced chemical vapor deposition. Even and controllable bending of the nanowires has been observed after a rapid thermal annealing in a N2 atmosphere. The mechanisms of the shape modification have been examined. This approach has been used to form electrical contacts to freestanding nano-objects as well as nano-`cages' for the purpose of securing ZnO tubs. These results suggest that thermally induced bending of nanowires may have potential applications in constructing three-dimensional nanodevices or complex structures for the immobilization of particles and large molecules.

  4. Surface functionalization for tailoring the aggregation and magnetic behaviour of silica-coated iron oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Roca, A. G.; Carmona, D.; Miguel-Sancho, N.; Bomatí-Miguel, O.; Balas, F.; Piquer, C.; Santamaría, J.

    2012-04-01

    We report here a detailed structural and magnetic study of different silica nanocapsules containing uniform and highly crystalline maghemite nanoparticles. The magnetic phase consists of 5 nm triethylene glycol (TREG)- or dimercaptosuccinic acid (DMSA)-coated maghemite particles. TREG-coated nanoparticles were synthesized by thermal decomposition. In a second step, TREG ligands were exchanged by DMSA. After the ligand exchange, the ζ potential of the particles changed from - 10 to - 40 mV, whereas the hydrodynamic size remained constant at around 15 nm. Particles coated by TREG and DMSA were encapsulated in silica following a sol-gel procedure. The encapsulation of TREG-coated nanoparticles led to large magnetic aggregates, which were embedded in coalesced silica structures. However, DMSA-coated nanoparticles led to small magnetic clusters inserted in silica spheres of around 100 nm. The final nanostructures can be described as the result of several competing factors at play. Magnetic measurements indicate that in the TREG-coated nanoparticles the interparticle magnetic interaction scenario has not dramatically changed after the silica encapsulation, whereas in the DMSA-coated nanoparticles, the magnetic interactions were screened due to the function of the silica template. Moreover, the analysis of the AC susceptibility suggests that our systems essentially behave as cluster spin glass systems.

  5. Modeling Bamboo as a Functionally Graded Material

    NASA Astrophysics Data System (ADS)

    Silva, Emílio Carlos Nelli; Walters, Matthew C.; Paulino, Glaucio H.

    2008-02-01

    Natural fibers are promising for engineering applications due to their low cost. They are abundantly available in tropical and subtropical regions of the world, and they can be employed as construction materials. Among natural fibers, bamboo has been widely used for housing construction around the world. Bamboo is an optimized composite material which exploits the concept of Functionally Graded Material (FGM). Biological structures, such as bamboo, are composite materials that have complicated shapes and material distribution inside their domain, and thus the use of numerical methods such as the finite element method and multiscale methods such as homogenization, can help to further understanding of the mechanical behavior of these materials. The objective of this work is to explore techniques such as the finite element method and homogenization to investigate the structural behavior of bamboo. The finite element formulation uses graded finite elements to capture the varying material distribution through the bamboo wall. To observe bamboo behavior under applied loads, simulations are conducted considering a spatially-varying Young's modulus, an averaged Young's modulus, and orthotropic constitutive properties obtained from homogenization theory. The homogenization procedure uses effective, axisymmetric properties estimated from the spatially-varying bamboo composite. Three-dimensional models of bamboo cells were built and simulated under tension, torsion, and bending load cases.

  6. Modeling Bamboo as a Functionally Graded Material

    SciTech Connect

    Silva, Emilio Carlos Nelli; Walters, Matthew C.; Paulino, Glaucio H.

    2008-02-15

    Natural fibers are promising for engineering applications due to their low cost. They are abundantly available in tropical and subtropical regions of the world, and they can be employed as construction materials. Among natural fibers, bamboo has been widely used for housing construction around the world. Bamboo is an optimized composite material which exploits the concept of Functionally Graded Material (FGM). Biological structures, such as bamboo, are composite materials that have complicated shapes and material distribution inside their domain, and thus the use of numerical methods such as the finite element method and multiscale methods such as homogenization, can help to further understanding of the mechanical behavior of these materials. The objective of this work is to explore techniques such as the finite element method and homogenization to investigate the structural behavior of bamboo. The finite element formulation uses graded finite elements to capture the varying material distribution through the bamboo wall. To observe bamboo behavior under applied loads, simulations are conducted considering a spatially-varying Young's modulus, an averaged Young's modulus, and orthotropic constitutive properties obtained from homogenization theory. The homogenization procedure uses effective, axisymmetric properties estimated from the spatially-varying bamboo composite. Three-dimensional models of bamboo cells were built and simulated under tension, torsion, and bending load cases.

  7. Review of Recent Progress of Plasmonic Materials and Nano-Structures for Surface-Enhanced Raman Scattering

    PubMed Central

    Wang, Alan X.; Kong, Xianming

    2016-01-01

    Surface-enhanced Raman scattering (SERS) has demonstrated single-molecule sensitivity and is becoming intensively investigated due to its significant potential in chemical and biomedical applications. SERS sensing is highly dependent on the substrate, where excitation of the localized surface plasmons (LSPs) enhances the Raman scattering signals of proximate analyte molecules. This paper reviews research progress of SERS substrates based on both plasmonic materials and nano-photonic structures. We first discuss basic plasmonic materials, such as metallic nanoparticles and nano-rods prepared by conventional bottom-up chemical synthesis processes. Then, we review rationally-designed plasmonic nano-structures created by top-down approaches or fine-controlled synthesis with high-density hot-spots to provide large SERS enhancement factors (EFs). Finally, we discuss the research progress of hybrid SERS substrates through the integration of plasmonic nano-structures with other nano-photonic devices, such as photonic crystals, bio-enabled nanomaterials, guided-wave systems, micro-fluidics and graphene. PMID:26900428

  8. Efficiency enhancement due to self-organization of nano-structures in Cd(S, Te) solar cell material

    NASA Astrophysics Data System (ADS)

    Sato, Kazunori; Katayama-Yoshida, Hiroshi

    2014-03-01

    CdTe is one of the most important solar cell materials. Its energy gap is 1.44 eV, which is ideal for solar cell application. So far, conversion efficiency of 18.3 percent has been realized, but it is lower than the Shockley-Queisser limit. In this paper, we propose computational materials design for enhancing conversion efficiency by using self-organization in Cd(Te, S) alloy semiconductor. Firstly, we performed cluster expansion of total energy of the Cd(Te, S) system and simulated self-organization of nano-structures in Cd(Te, S) by using Monte Carlo method. It is found that layered structure becomes stable by applying strain during the crystal growth. The electronic structure of the self-organized layered structure was calculated by using the hybrid method (HSE06) implemented in the VASP code to derive optical absorption coefficient. By using the calculated absorption coefficient the efficiency limit was derived based on the Shockley-Queisser theory. It is shown that the efficiency limit does not change so much due to the nano-structure formation. However, our calculation shows spatial separation between photo-generated electrons and holes. This might enhance the efficiency due to the suppression of recombination.

  9. Interfacing nanostructures to biological cells

    DOEpatents

    Chen, Xing; Bertozzi, Carolyn R.; Zettl, Alexander K.

    2012-09-04

    Disclosed herein are methods and materials by which nanostructures such as carbon nanotubes, nanorods, etc. are bound to lectins and/or polysaccharides and prepared for administration to cells. Also disclosed are complexes comprising glycosylated nanostructures, which bind selectively to cells expressing glycosylated surface molecules recognized by the lectin. Exemplified is a complex comprising a carbon nanotube functionalized with a lipid-like alkane, linked to a polymer bearing repeated .alpha.-N-acetylgalactosamine sugar groups. This complex is shown to selectively adhere to the surface of living cells, without toxicity. In the exemplified embodiment, adherence is mediated by a multivalent lectin, which binds both to the cells and the .alpha.-N-acetylgalactosamine groups on the nanostructure.

  10. Crystallization of Oxides as Functional Materials

    NASA Astrophysics Data System (ADS)

    Sun, Congting; Song, Shuyan; Xue, Dongfeng; Zhang, Hongjie

    2012-06-01

    Crystallization is essential to the manufacture of functional materials as varies as electronic devices, energy storage and conversion devices, and highly reactive catalysts. As an important part of functional materials, metal oxides possess wide applications and the crystallization of oxide materials has thus received considerable attention from both fundamental and technological perspectives. With particular emphasis on our recent laboratory results, this feature article gives a brief review in the field of crystallization of oxides. On the basis of chemical bonding theory of single crystal growth, we have simulated thermodynamic growth behaviors of various functional oxides such as ZnO, MgO, Cu2O, Nb2O5, V2O5, MnO2, SnO2, NiO, KDP/ADP, LiNbO3, and NaNbO3. Quantitatively analyzing bonding conditions of controllable crystallographic faces enables us to design proper synthesis strategies and optimize growth parameters, consequently obtaining functional oxides with desirable crystallization behaviors.

  11. Prevention of microbial biofilms - the contribution of micro and nanostructured materials.

    PubMed

    Grumezescu, Alexandru Mihai; Chifiriuc, Carmen Mariana

    2014-01-01

    Microbial biofilms are associated with drastically enhanced resistance to most of the antimicrobial agents and with frequent treatment failures, generating the search for novel strategies which can eradicate infections by preventing the persistent colonization of the hospital environment, medical devices or human tissues. Some of the current approaches for fighting biofilms are represented by the development of novel biomaterials with increased resistance to microbial colonization and by the improvement of the current therapeutic solutions with the aid of nano (bio)technology. This special issues includes papers describing the applications of nanotechnology and biomaterials science for the development of improved drug delivery systems and nanostructured surfaces for the prevention and treatment of medical biofilms. Nanomaterials display unique and well-defined physical and chemical properties making them useful for biomedical applications, such as: very high surface area to volume ratio, biocompatibility, biodegradation, safety for human ingestion, capacity to support surface modification and therefore, to be combined with other bioactive molecules or substrata and more importantly being seemingly not attracting antimicrobial resistance. The use of biomaterials is significantly contributing to the reduction of the excessive use of antibiotics, and consequently to the decrease of the emergence rate of resistant microorganisms, as well as of the associated toxic effects. Various biomaterials with intrinsic antimicrobial activity (inorganic nanoparticles, polymers, composites), medical devices for drug delivery, as well as factors influencing their antimicrobial properties are presented. One of the presented papers reviews the recent literature on the use of magnetic nanoparticles (MNP)-based nanomaterials in antimicrobial applications for biomedicine, focusing on the growth inhibition and killing of bacteria and fungi, and, on viral inactivation. The anti

  12. Micro-nanostructured CuO/C spheres as high-performance anode materials for Na-ion batteries

    NASA Astrophysics Data System (ADS)

    Lu, Yanying; Zhang, Ning; Zhao, Qing; Liang, Jing; Chen, Jun

    2015-01-01

    In this paper, we report on the synthesis of micro-nanostructured CuO/C spheres by aerosol spray pyrolysis and their application as high-performance anodes in sodium-ion batteries. Micro-nanostructured CuO/C spheres with different CuO contents were synthesized through aerosol spray pyrolysis by adjusting the ratio of reactants and heat-treated by an oxidation process. The as-prepared CuO/C spheres show uniformly spherical morphology, in which CuO nanoparticles (~10 nm) are homogeneously embedded in the carbon matrix (denoted as 10-CuO/C). The electrochemical performance of 10-CuO/C with a carbon weight of 44% was evaluated as the anode material for Na-ion batteries. It can deliver a capacity of 402 mA h g-1 after 600 cycles at a current density of 200 mA g-1. Furthermore, a capacity of 304 mA h g-1 was obtained at a high current density of 2000 mA g-1. The superior electrochemical performance of the micro-nanostructured CuO/C spheres leads to the enhancement of the electronic conductivity of the nanocomposite and the accommodation of the volume variation of CuO/C during charge/discharge cycling.In this paper, we report on the synthesis of micro-nanostructured CuO/C spheres by aerosol spray pyrolysis and their application as high-performance anodes in sodium-ion batteries. Micro-nanostructured CuO/C spheres with different CuO contents were synthesized through aerosol spray pyrolysis by adjusting the ratio of reactants and heat-treated by an oxidation process. The as-prepared CuO/C spheres show uniformly spherical morphology, in which CuO nanoparticles (~10 nm) are homogeneously embedded in the carbon matrix (denoted as 10-CuO/C). The electrochemical performance of 10-CuO/C with a carbon weight of 44% was evaluated as the anode material for Na-ion batteries. It can deliver a capacity of 402 mA h g-1 after 600 cycles at a current density of 200 mA g-1. Furthermore, a capacity of 304 mA h g-1 was obtained at a high current density of 2000 mA g-1. The superior

  13. A silica sol-gel design strategy for nanostructured metallic materials.

    PubMed

    Warren, Scott C; Perkins, Matthew R; Adams, Ashley M; Kamperman, Marleen; Burns, Andrew A; Arora, Hitesh; Herz, Erik; Suteewong, Teeraporn; Sai, Hiroaki; Li, Zihui; Werner, Jörg; Song, Juho; Werner-Zwanziger, Ulrike; Zwanziger, Josef W; Grätzel, Michael; DiSalvo, Francis J; Wiesner, Ulrich

    2012-03-18

    Batteries, fuel cells and solar cells, among many other high-current-density devices, could benefit from the precise meso- to macroscopic structure control afforded by the silica sol-gel process. The porous materials made by silica sol-gel chemistry are typically insulators, however, which has restricted their application. Here we present a simple, yet highly versatile silica sol-gel process built around a multifunctional sol-gel precursor that is derived from the following: amino acids, hydroxy acids or peptides; a silicon alkoxide; and a metal acetate. This approach allows a wide range of biological functionalities and metals--including noble metals--to be combined into a library of sol-gel materials with a high degree of control over composition and structure. We demonstrate that the sol-gel process based on these precursors is compatible with block-copolymer self-assembly, colloidal crystal templating and the Stöber process. As a result of the exceptionally high metal content, these materials can be thermally processed to make porous nanocomposites with metallic percolation networks that have an electrical conductivity of over 1,000 S cm(-1). This improves the electrical conductivity of porous silica sol-gel nanocomposites by three orders of magnitude over existing approaches, opening applications to high-current-density devices.

  14. Application of DC plasma torch for synthesis of carbon nanostructured materials

    NASA Astrophysics Data System (ADS)

    Shavelkina, M. B.; Amirov, R. H.; Katarzhis, V. A.; Kiselev, V. I.

    2016-09-01

    The results of the synthesis of carbon nanostructures at high temperatures using a DC plasma torch are presented. Plasma was generated by introduction of argon, nitrogen and helium into the plasma torch with an anode in the form of an expanding channel. Sustainable modes of the plasma torch operation have been achieved by simultaneous tangential input of a plasma gas with a carbon source. Obtained solid products were studied using electron microscopy, thermogravimetry, Raman spectroscopy and X-ray diffraction to characterize their properties and morphological structures.

  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. Hybrid nanostructures for energy storage applications.

    PubMed

    Mohana Reddy, Arava Leela; Gowda, Sanketh R; Shaijumon, Manikoth M; Ajayan, Pulickel M

    2012-09-25

    Materials engineering plays a key role in the field of energy storage. In particular, engineering materials at the nanoscale offers unique properties resulting in high performance electrodes and electrolytes in various energy storage devices. Consequently, considerable efforts have been made in recent years to fulfill the future requirements of electrochemical energy storage using these advanced materials. Various multi-functional hybrid nanostructured materials are currently being studied to improve energy and power densities of next generation storage devices. This review describes some of the recent progress in the synthesis of different types of hybrid nanostructures using template assisted and non-template based methods. The potential applications and recent research efforts to utilize these hybrid nanostructures to enhance the electrochemical energy storage properties of Li-ion battery and supercapacitor are discussed. This review also briefly outlines some of the recent progress and new approaches being explored in the techniques of fabrication of 3D battery structures using hybrid nanoarchitectures.

  17. Nanostructured scaffolds for bone tissue engineering.

    PubMed

    Li, Xiaoming; Wang, Lu; Fan, Yubo; Feng, Qingling; Cui, Fu-Zhai; Watari, Fumio

    2013-08-01

    It has been demonstrated that nanostructured materials, compared with conventional materials, may promote greater amounts of specific protein interactions, thereby more efficiently stimulating new bone formation. It has also been indicated that, when features or ingredients of scaffolds are nanoscaled, a variety of interactions can be stimulated at the cellular level. Some of those interactions induce favorable cellular functions while others may leads to toxicity. This review presents the mechanism of interactions between nanoscaled materials and cells and focuses on the current research status of nanostructured scaffolds for bone tissue engineering. Firstly, the main requirements for bone tissue engineering scaffolds were discussed. Then, the mechanism by which nanoscaled materials promote new bone formation was explained, following which the current research status of main types of nanostructured scaffolds for bone tissue engineering was reviewed and discussed.

  18. Nano-structured and functionalized surfaces for cytocompatibility improvement and bactericidal action.

    PubMed

    Slepicka, Petr; Kasalkova, Nikola Slepickova; Siegel, Jakub; Kolska, Zdenka; Bacakova, Lucie; Svorcik, Vaclav

    2015-11-01

    The field of material surface modification with the aim of biomaterial construction involves several approaches of treatments that allow the preparation of materials, which positively influence adhesion of cells and their proliferation and thus aid and improve tissue formation. Modified materials have a surface composition and morphology intended to interact with biological systems and cellular functions. Not only surface chemistry has an effect on material biological response, surface structures of different morphology can be constructed to guide a desirable biological outcome. Nano-patterned material surfaces have been tested with the aim of how surface geometry and physical properties on a micro- and nano-scale can affect cellular response and influence cell adhesion and proliferation. Biological functionality of solid state substrates was significantly improved by the irradiation of material with plasma discharge or laser treatment. Commonly used "artificial" polymers (e.g. polyethylene (PE), polystyrene (PS), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN)) and biopolymers (e.g. Poly-l-Lactic acid (PLLA), polymethylpentene (PMP)) were treated with aim of biocompatibility improvement. The treatment of polymer/biopolymer substrates leads to formation of ripple or wrinkle-like structures, supported also with heat treatment or other subsequent surface processing. Several types of chemically different substances (e.g. metal or carbon nano-particles, proteins) were grafted onto material surfaces or built into material structures by different processes. Surface physico-chemical properties (e.g. chemistry, charge, morphology, wettability, electrical conductivity, optical and mechanical properties) of treated surfaces were determined. The enhancement of adhesion and proliferation of cells on modified substrates was investigated in vitro. Bactericidal action of noble metal nano-particles (e.g. Au, Ag) on polymers was

  19. MicroRNA-triggered, cascaded and catalytic self-assembly of functional ``DNAzyme ferris wheel'' nanostructures for highly sensitive colorimetric detection of cancer cells

    NASA Astrophysics Data System (ADS)

    Zhou, Wenjiao; Liang, Wenbin; Li, Xin; Chai, Yaqin; Yuan, Ruo; Xiang, Yun

    2015-05-01

    The construction of DNA nanostructures with various sizes and shapes has significantly advanced during the past three decades, yet the application of these DNA nanostructures for solving real problems is still in the early stage. On the basis of microRNA-triggered, catalytic self-assembly formation of the functional ``DNAzyme ferris wheel'' nanostructures, we show here a new signal amplification platform for highly sensitive, label-free and non-enzyme colorimetric detection of a small number of human prostate cancer cells. The microRNA (miR-141), which is catalytically recycled and reused, triggers isothermal self-assembly of a pre-designed, G-quadruplex sequence containing hairpin DNAs into ``DNAzyme ferris wheel''-like nanostructures (in association with hemin) with horseradish peroxidase mimicking activity. These DNAzyme nanostructures catalyze an intensified color transition of the probe solution for highly sensitive detection of miR-141 down to 0.5 pM with the naked eye, and the monitoring of as low as 283 human prostate cancer cells can also, theoretically, be achieved in a colorimetric approach. The work demonstrated here thus offers new opportunities for the construction of functional DNA nanostructures and for the application of these DNA nanostructures as an effective signal amplification means in the sensitive detection of nucleic acid biomarkers.

  20. Low work function thermionic emission materials

    SciTech Connect

    Zavadil, K.R.; King, D.B.; Ruffner, J.A.

    1999-11-01

    Thermionic energy conversion in a microminiature format shows potential as a viable, high efficiency, on-chip power source. Microminiature thermionic converters (MTC) with inter-electrode spacings on the order of microns are currently being prototyped and evaluated at Sandia. The remaining enabling technology is the development of low work function materials and processes than can be integrated into these converters. In this report, the authors demonstrate a method of incorporating thin film emitters into converters using rf sputtering. They find that the resultant films possess a minimum work function of 1.2 eV. Practical energy conversion is hindered by surface work function non-uniformity. They postulate the source of this heterogeneity to be a result of limited bulk and surface transport of barium. Several methods are proposed for maximizing transport, including increased film porosity and the use of metal terminating layers. They demonstrate a novel method for incorporating film porosity based on metal interlayer coalescence.

  1. Optimizing the Binding Energy of Hydrogen on Nanostructured Carbon Materials through Structure Control and Chemical Doping

    SciTech Connect

    Jie Liu

    2011-02-01

    The DOE Hydrogen Sorption Center of Excellence (HSCoE) was formed in 2005 to develop materials for hydrogen storage systems to be used in light-duty vehicles. The HSCoE and two related centers of excellence were created as follow-on activities to the DOE Office of Energy Efficiency and Renewable Energy’s (EERE’s) Hydrogen Storage Grand Challenge Solicitation issued in FY 2003. The Hydrogen Sorption Center of Excellence (HSCoE) focuses on developing high-capacity sorbents with the goal to operate at temperatures and pressures approaching ambient and be efficiently and quickly charged in the tank with minimal energy requirements and penalties to the hydrogen fuel infrastructure. The work was directed at overcoming barriers to achieving DOE system goals and identifying pathways to meet the hydrogen storage system targets. To ensure that the development activities were performed as efficiently as possible, the HSCoE formed complementary, focused development clusters based on the following four sorption-based hydrogen storage mechanisms: 1. Physisorption on high specific surface area and nominally single element materials 2. Enhanced H2 binding in Substituted/heterogeneous materials 3. Strong and/or multiple H2 binding from coordinated but electronically unsatruated metal centers 4. Weak Chemisorption/Spillover. As a member of the team, our group at Duke studied the synthesis of various carbon-based materials, including carbon nanotubes and microporous carbon materials with controlled porosity. We worked closely with other team members to study the effect of pore size on the binding energy of hydrogen to the carbon –based materials. Our initial project focus was on the synthesis and purification of small diameter, single-walled carbon nanotubes (SWNTs) with well-controlled diameters for the study of their hydrogen storage properties as a function of diameters. We developed a chemical vapor deposition method that synthesized gram quantities of carbon nanotubes with

  2. Tuning the work function of randomly oriented ZnO nanostructures by capping with faceted Au nanostructure and oxygen defects: enhanced field emission experiments and DFT studies

    NASA Astrophysics Data System (ADS)

    Ghosh, Arnab; Guha, Puspendu; Thapa, Ranjit; Selvaraj, Sinthika; Kumar, Mohit; Rakshit, Bipul; Dash, Tapan; Bar, Rajshekhar; Ray, Samit K.; Venkata Satyam, Parlapalli

    2016-03-01

    The lowering of the work function (Φ) can lead to a better field emission (FE) behavior at lower threshold fields. We report on enhanced FE from randomly oriented and faceted Au-capped ZnO hetero-nanostructures (HNs) having more oxygen defects. Large-area arrays of non-aligned, faceted Au-capped ZnO HNs, such as nanowires (NWs) and triangular nanoflakes (TNFs) are grown using the chemical vapor deposition (CVD) method. Enhanced FE properties from the TNF sample resulted in a turn-on field as low as 0.52 V μm-1 at a current density of 0.1 mA cm-2 and a field enhancement factor (β) as high as ≈5.16 × 105. Under similar experimental conditions, drawing the same current density from an NW specimen needs a higher turn-on field (0.86 V μm-1) and to exhibit nearly four times less field enhancement factor compared to the TNFs samples. X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) measurements confirm the presence of more oxygen defects in the TNF samples compared to the NW samples. Kelvin probe force microscopy (KPFM) measurements show the average local work function to be 4.70 ± 0.1 eV for the TNF sample, which is ≈ 0.34 eV lower than the NW sample. Using density functional theory (DFT) calculations, the estimated Φ values are found to be 4.98 eV for ZnO(0001), 4.17 eV for Au(001)/ZnO(0001) and 3.91 eV for Au(001)/Ovac-ZnO(0001) surfaces. The DFT results are qualitatively in agreement with our experimental results. The presence of Au nanostructures on top of O-deficient and sharp-tipped TNFs results in enhanced FE performance following their reduced tunneling barrier via pinning of effective Φ.

  3. Tuning the work function of randomly oriented ZnO nanostructures by capping with faceted Au nanostructure and oxygen defects: enhanced field emission experiments and DFT studies.

    PubMed

    Ghosh, Arnab; Guha, Puspendu; Thapa, Ranjit; Selvaraj, Sinthika; Kumar, Mohit; Rakshit, Bipul; Dash, Tapan; Bar, Rajshekhar; Ray, Samit K; Satyam, Parlapalli Venkata

    2016-03-29

    The lowering of the work function (Φ) can lead to a better field emission (FE) behavior at lower threshold fields. We report on enhanced FE from randomly oriented and faceted Au-capped ZnO hetero-nanostructures (HNs) having more oxygen defects. Large-area arrays of non-aligned, faceted Au-capped ZnO HNs, such as nanowires (NWs) and triangular nanoflakes (TNFs) are grown using the chemical vapor deposition (CVD) method. Enhanced FE properties from the TNF sample resulted in a turn-on field as low as 0.52 V μm(-1) at a current density of 0.1 mA cm(-2) and a field enhancement factor (β) as high as ≈5.16 × 10(5). Under similar experimental conditions, drawing the same current density from an NW specimen needs a higher turn-on field (0.86 V μm(-1)) and to exhibit nearly four times less field enhancement factor compared to the TNFs samples. X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) measurements confirm the presence of more oxygen defects in the TNF samples compared to the NW samples. Kelvin probe force microscopy (KPFM) measurements show the average local work function to be 4.70 ± 0.1 eV for the TNF sample, which is ≈ 0.34 eV lower than the NW sample. Using density functional theory (DFT) calculations, the estimated Φ values are found to be 4.98 eV for ZnO(0001), 4.17 eV for Au(001)/ZnO(0001) and 3.91 eV for Au(001)/Ovac-ZnO(0001) surfaces. The DFT results are qualitatively in agreement with our experimental results. The presence of Au nanostructures on top of O-deficient and sharp-tipped TNFs results in enhanced FE performance following their reduced tunneling barrier via pinning of effective Φ. PMID:26883495

  4. A Rationally Designed Connector for Assembly of Protein-Functionalized DNA Nanostructures.

    PubMed

    Koßmann, Katja J; Ziegler, Cornelia; Angelin, Alessandro; Meyer, Rebecca; Skoupi, Marc; Rabe, Kersten S; Niemeyer, Christof M

    2016-06-16

    We report on the rational engineering of the binding interface of the self-ligating HaloTag protein to generate an optimized linker for DNA nanostructures. Five amino acids positioned around the active-site entry channel for the chlorohexyl ligand (CH) of the HaloTag protein were exchanged for positively charged lysine amino acids to produce the HOB (halo-based oligonucleotide binder) protein. HOB was genetically fused with the enzyme cytochrome P450 BM3, as well as with BMR, the separated reductase domain of BM3. The resulting HOB-fusion proteins revealed significantly improved rates in ligation with CH-modified oligonucleotides and DNA origami nanostructures. These results suggest that the efficient self-assembly of protein-decorated DNA structures can be greatly improved by fine-tuning of the electrostatic interactions between proteins and the negatively charged nucleic acid nanostructures. PMID:26972311

  5. A Rationally Designed Connector for Assembly of Protein-Functionalized DNA Nanostructures.

    PubMed

    Koßmann, Katja J; Ziegler, Cornelia; Angelin, Alessandro; Meyer, Rebecca; Skoupi, Marc; Rabe, Kersten S; Niemeyer, Christof M

    2016-06-16

    We report on the rational engineering of the binding interface of the self-ligating HaloTag protein to generate an optimized linker for DNA nanostructures. Five amino acids positioned around the active-site entry channel for the chlorohexyl ligand (CH) of the HaloTag protein were exchanged for positively charged lysine amino acids to produce the HOB (halo-based oligonucleotide binder) protein. HOB was genetically fused with the enzyme cytochrome P450 BM3, as well as with BMR, the separated reductase domain of BM3. The resulting HOB-fusion proteins revealed significantly improved rates in ligation with CH-modified oligonucleotides and DNA origami nanostructures. These results suggest that the efficient self-assembly of protein-decorated DNA structures can be greatly improved by fine-tuning of the electrostatic interactions between proteins and the negatively charged nucleic acid nanostructures.

  6. Comparative Incorporation of PNA into DNA Nanostructures.

    PubMed

    Pedersen, Ronnie O; Kong, Jing; Achim, Catalina; LaBean, Thomas H

    2015-09-23

    DNA has shown great promise as a building material for self-assembling nanoscale structures. To further develop the potential of this technology, more methods are needed for functionalizing DNA-based nanostructures to increase their chemical diversity. Peptide nucleic acid (PNA) holds great promise for realizing this goal, as it conveniently allows for inclusion of both amino acids and peptides in nucleic acid-based structures. In this work, we explored incorporation of a positively charged PNA within DNA nanostructures. We investigated the efficiency of annealing a lysine-containing PNA probe with complementary, single-stranded DNA sequences within nanostructures, as well as the efficiency of duplex invasion and its dependence on salt concentration. Our results show that PNA allows for toehold-free strand displacement and that incorporation yield depends critically on binding site geometry. These results provide guidance for the design of PNA binding sites on nucleic acid nanostructures with an eye towards optimizing fabrication yield.

  7. Nanoscale quantitative measurement of the potential of charged nanostructures by electrostatic and Kelvin probe force microscopy: unraveling electronic processes in complex materials.

    PubMed

    Liscio, Andrea; Palermo, Vincenzo; Samorì, Paolo

    2010-04-20

    In microelectronics and biology, many fundamental processes involve the exchange of charges between small objects, such as nanocrystals in photovoltaic blends or individual proteins in photosynthetic reactions. Because these nanoscale electronic processes strongly depend on the structure of the electroactive assemblies, a detailed understanding of these phenomena requires unraveling the relationship between the structure of the nano-object and its electronic function. Because of the fragility of the structures involved and the dynamic variance of the electric potential of each nanostructure during the charge generation and transport processes, understanding this structure-function relationship represents a great challenge. This Account discusses how our group and others have exploited scanning probe microscopy based approaches beyond imaging, particularly Kelvin probe force microscopy (KPFM), to map the potential of different nanostructures with a spatial and voltage resolution of a few nanometers and millivolts, respectively. We describe in detail how these techniques can provide researchers several types of chemical information. First, KPFM allows researchers to visualize the photogeneration and splitting of several unitary charges between well-defined nano-objects having complementary electron-acceptor and -donor properties. In addition, this method maps charge injection and transport in thin layers of polycrystalline materials. Finally, KPFM can monitor the activity of immobilized chemical components of natural photosynthetic systems. In particular, researchers can use KPFM to measure the electric potential without physical contact between the tip and the nanostructure studied. These measurements exploit long-range electrostatic interactions between the scanning probe and the sample, which scale with the square of the probe-sample distance, d. While allowing minimal perturbation, these long-range interactions limit the resolution attainable in the measurement

  8. Micro- and nanostructure of the adhesive material secreted by the tube feet of the sea star Asterias rubens.

    PubMed

    Hennebert, Elise; Viville, Pascal; Lazzaroni, Roberto; Flammang, Patrick

    2008-10-01

    To attach to underwater surfaces, sea stars rely on adhesive secretions produced by specialised organs, the tube feet. Adhesion is temporary and tube feet can also voluntarily become detached. The adhesive material is produced by two types of adhesive secretory cells located in the epidermis of the tube foot disc, and is deposited between the disc surface and the substratum. After detachment, this material remains on the substratum as a footprint. Using LM, SEM, and AFM, we described the fine structure of footprints deposited on various substrata by individuals of Asterias rubens. Ultrastructure of the adhesive layer of attached tube feet was also investigated using TEM. Whatever the method used, the adhesive material appeared as made up of globular nanostructures forming a meshwork deposited on a thin homogeneous film. This appearance did not differ according to whether the footprints were fixed or not, and whether they were observed hydrated or dry. TEM observations suggest that type 2 adhesive cells would be responsible for the release of the material constituting the homogeneous film whereas type 1 adhesive cells would produce the material forming the meshwork. This reticulated pattern would originate from the arrangement of the adhesive cell secretory pores on the disc surface.

  9. Magnetic spectroscopy and microscopy of functional materials

    SciTech Connect

    Jenkins, Catherine Ann

    2011-05-01

    Heusler intermetallics Mn2Y Ga and X2MnGa (X; Y =Fe, Co, Ni) undergo tetragonal magnetostructural transitions that can result in half metallicity, magnetic shape memory, or the magnetocaloric effect. Understanding the magnetism and magnetic behavior in functional materials is often the most direct route to being able to optimize current materials for todays applications and to design novel ones for tomorrow. Synchrotron soft x-ray magnetic spectromicroscopy techniques are well suited to explore the the competing effects from the magnetization and the lattice parameters in these materials as they provide detailed element-, valence-, and site-specifc information on the coupling of crystallographic ordering and electronic structure as well as external parameters like temperature and pressure on the bonding and exchange. Fundamental work preparing the model systems of spintronic, multiferroic, and energy-related compositions is presented for context. The methodology of synchrotron spectroscopy is presented and applied to not only magnetic characterization but also of developing a systematic screening method for future examples of materials exhibiting any of the above effects. The chapter progression is as follows: an introduction to the concepts and materials under consideration (Chapter 1); an overview of sample preparation techniques and results, and the kinds of characterization methods employed (Chapter 2); spectro- and microscopic explorations of X2MnGa/Ge (Chapter 3); spectroscopic investigations of the composition series Mn2Y Ga to the logical Mn3Ga endpoint (Chapter 4); and a summary and overview of upcoming work (Chapter 5). Appendices include the results of a Think Tank for the Graduate School of Excellence MAINZ (Appendix A) and details of an imaging project now in progress on magnetic reversal and domain wall observation in the classical Heusler material Co2FeSi (Appendix B).

  10. A study of nanostructure magnetosolid Nd-Ho-Fe-Co-B materials via atomic force microscopy and magnetic force microscopy

    NASA Astrophysics Data System (ADS)

    Andreeva, N. V.; Filimonov, A. V.; Rudskoi, A. I.; Burkhanov, G. S.; Tereshina, I. S.; Politova, G. A.; Pelevin, I. A.

    2016-09-01

    Nanostructure Nd-Ho-Fe-Co-B alloys have been probed via atomic force microscopy and magnetic force microscopy (AFM and MFM, respectively). The ribbon samples with a thickness of ~30 μm are prepared via the rapid solidification on a rotating copper barrel. A part of samples has been subjected to hydration, whereas another one has undergone severe plastic deformation. AFM was mainly used to study the contact and free surface of ribbon samples. This has enabled us to establish the topography, structure, defects of both sides, morphology of magnetic inclusions of the initial quenched samples and the materials subjected to the subsequent external effects. The AFM and MFM data allowed the magnetic hysteresis properties of the bulk samples with the identical composition to be interpreted.

  11. Advanced nanostructured materials and their application for improvement of sun-light harvesting and efficiency of solar cells

    NASA Astrophysics Data System (ADS)

    Dimova-Malinovska, D.

    2016-02-01

    This review describes the application of different nanostructured materials in solar cells technology for improvement of sun-light harvesting and their efficiency. Several approaches have recently been proposed to increase the efficiency of solar cells above the theoretical limit which are based on a “photon management” concept that employs such phenomena as: (i) down-conversion, and (ii) surface plasmon resonance effect (iii) decreasing of the loss due to the reflection of the radiation, (iv) increasing of the reflection from the back contact, v) increasing of the effective solar cells surface, etc. The results demonstrate the possibility for to increasing of light harvesting, short circuit current and efficiency by application of nanomaterials in thin film and hetero-junction (HJ) solar cells. The first promising results allow an expectation for application of advanced nanomaterials in the 3d generation solar cells.

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

    PubMed

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

    2011-01-12

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

  13. High Speed SPM of Functional Materials

    SciTech Connect

    Huey, Bryan D.

    2015-08-14

    The development and optimization of applications comprising functional materials necessitates a thorough understanding of their static and dynamic properties and performance at the nanoscale. Leveraging High Speed SPM and concepts enabled by it, efficient measurements and maps with nanoscale and nanosecond temporal resolution are uniquely feasible. This includes recent enhancements for topographic, conductivity, ferroelectric, and piezoelectric properties as originally proposed, as well as newly developed methods or improvements to AFM-based mechanical, friction, thermal, and photoconductivity measurements. The results of this work reveal fundamental mechanisms of operation, and suggest new approaches for improving the ultimate speed and/or efficiency, of data storage systems, magnetic-electric sensors, and solar cells.

  14. Photothermal characterization of functionally graded materials (FGM)

    NASA Astrophysics Data System (ADS)

    Jumel, J.; Terrien, N.; Arnould, O.; Krapez, J. C.; Lepoutre, F.

    2002-05-01

    This paper deals with the photothermal characterization of functionally graded materials (FGM) whose thermal properties are varying parallel to the sample surface. Simple experimental configurations and associated inversion procedures are proposed either for thermal mapping or for pitch-catch imaging mode. The photothermally induced periodic temperature field at the sample surface is first calculated using a specific code, then the inversion procedures are checked using a simulated set of data. Preliminary experimental results are presented outlining need of specific filter to cope with experimental noise.

  15. Gen IV Materials Handbook Functionalities and Operation

    SciTech Connect

    Ren, Weiju

    2009-12-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  16. Surface Functionalization of Graphene-based Materials

    NASA Astrophysics Data System (ADS)

    Mathkar, Akshay

    Graphene-based materials have generated tremendous interest in the past decade. Manipulating their characteristics using wet-chemistry methods holds distinctive value, as it provides a means towards scaling up, while not being limited by yield. The majority of this thesis focuses on the surface functionalization of graphene oxide (GO), which has drawn tremendous attention as a tunable precursor due to its readily chemically manipulable surface and richly functionalized basal plane. Firstly, a room-temperature based method is presented to reduce GO stepwise, with each organic moiety being removed sequentially. Characterization confirms the carbonyl group to be reduced first, while the tertiary alcohol is reduced last, as the optical gap decrease from 3.5 eV down to 1 eV. This provides greater control over GO, which is an inhomogeneous system, and is the first study to elucidate the order of removal of each functional group. In addition to organically manipulating GO, this thesis also reports a chemical methodology to inorganically functionalize GO and tune its wetting characteristics. A chemical method to covalently attach fluorine atoms in the form of tertiary alkyl fluorides is reported, and confirmed by MAS 13C NMR, as two forms of fluorinated graphene oxide (FGO) with varying C/F and C/O ratios are synthesized. Introducing C-F bonds decreases the overall surface free energy, which drastically reduces GO's wetting behavior, especially in its highly fluorinated form. Ease of solution processing leads to development of sprayable inks that are deposited on a range of porous and nonporous surfaces to impart amphiphobicity. This is the first report that tunes the wetting characteristics of GO. Lastly as a part of a collaboration with ConocoPhillips, another class of carbon nanomaterials - carbon nanotubes (CNTs), have been inorganically functionalized to repel 30 wt% MEA, a critical solvent in CO 2 recovery. In addition to improving the solution processability of CNTs

  17. Nanostructured conductive polymers for advanced energy storage.

    PubMed

    Shi, Ye; Peng, Lele; Ding, Yu; Zhao, Yu; Yu, Guihua

    2015-10-01

    Conductive polymers combine the attractive properties associated with conventional polymers and unique electronic properties of metals or semiconductors. Recently, nanostructured conductive polymers have aroused considerable research interest owing to their unique properties over their bulk counterparts, such as large surface areas and shortened pathways for charge/mass transport, which make them promising candidates for broad applications in energy conversion and storage, sensors, actuators, and biomedical devices. Numerous synthetic strategies have been developed to obtain various conductive polymer nanostructures, and high-performance devices based on these nanostructured conductive polymers have been realized. This Tutorial review describes the synthesis and characteristics of different conductive polymer nanostructures; presents the representative applications of nanostructured conductive polymers as active electrode materials for electrochemical capacitors and lithium-ion batteries and new perspectives of functional materials for next-generation high-energy batteries, meanwhile discusses the general design rules, advantages, and limitations of nanostructured conductive polymers in the energy storage field; and provides new insights into future directions.

  18. Experimental Fracture Measurements of Functionally Graded Materials

    NASA Astrophysics Data System (ADS)

    Carpenter, Ray Douglas

    The primary objective of this research was to extend established fracture toughness testing methods to a new class of engineering materials known as functionally graded materials (FGMs). Secondary goals were to compare experimental results to those predicted by finite element models and to provide fracture test results as feedback toward optimizing processing parameters for the in-house synthesis of a MoSi2/SiC FGM. Preliminary experiments were performed on commercially pure (CP) Ti and uniform axial tensile tests resulted in mechanical property data including yield strength, 268 MPa, ultimate tensile strength, 470 MPa and Young's modulus, 110 GPa. Results from 3-point bending fracture experiments on CP Ti demonstrated rising R-curve behavior and experimentally determined JQ fracture toughness values ranged between 153 N/mm and 254 N/mm. Similar experimental protocols were used for fracture experiments on a 7- layered Ti/TiB FGM material obtained from Cercom in Vista, California. A novel technique for pre-cracking in reverse 4-point bending was developed for this ductile/brittle FGM material. Fracture test results exhibited rising R-curve behavior and estimated JQ fracture toughness values ranged from 0.49 N/mm to 2.63 N/mm. A 5- layered MoSi2/SiC FGM was synthesized using spark plasma sintering (SPS). Samples of this material were fracture tested and the results again exhibited a rising R-curve with KIC fracture toughness values ranging from 2.7 MPa-m1/2 to 6.0 MPa-m1/2. Finite Element Models predicted rising R-curve behavior for both of the FGM materials tested. Model results were in close agreement for the brittle MoSi2/SiC FGM. For the relatively more ductile Ti/TiB material, results were in close agreement at short crack lengths but diverged at longer crack lengths because the models accounted for fracture toughening mechanisms at the crack tip but not those acting in the crack wake.

  19. Fabrication of functional materials in microfluidics

    NASA Astrophysics Data System (ADS)

    Shum, Ho Cheung

    In this thesis, we present a study on how droplets prepared in microfluidics can be used for fabrication of functional materials. We utilize the high degree of fluidic control enabled by miniaturizing the channels to achieve monodisperse single and multiple emulsion with high encapsulation efficiency. By engineering the interfaces of such emulsions and/or applying appropriate reactions, novel functional materials have been fabricated for encapsulation and release applications and for carrying out reactions in confined environments. Glass capillary microfluidics is used in the majority of the thesis. Glass offers excellent solvent resistance to most organic solvents needed for fabricating the desired materials. In Chapter 1, we describe a double-emulsion-templated approach to form polymer vesicles, also known as polymersomes. By dissolving amphiphilic block copolymers in a volatile solvent, which forms the shell layer of double emulsions, polymersomes are formed after evaporation of the volatile solvent. In Chapter 2, we apply the same approach to fabricate phospholipid vesicles. In Chapter 3, we investigate the physics of membrane formation at interfaces laden with amphiphilic diblock copolymers. In Chapter 4, we fabricate polymersomes with multiple compaitalents by using controlled double emulsion drops with multiple inner droplets as templates. In Chapter 5, we describe a non-microfluidic approach for fabricating similar polymersomes with large number of compartments. In Chapter 6, we show that the double-emulsion templated approach for forming polymersomes can be applied to two-dimensional stamped devices, which can be easily scaled up for production of large amount of polymersomes. Apart from polymersomes, controlled emulsions can also be used for generating other functional materials. In Chapter 7, we use double emulsion drops as microreactors for fabricating particles of hydroxyapatite. In Chapter 8, we generate solid capsules by emulsifying a molten phase as

  20. The Synthesis of Functional Mesoporous Materials

    SciTech Connect

    Fryxell, Glen E.

    2006-11-01

    The ability to decorate a silica surface with specific ligand fields and/or metal complexes creates powerful new capabilities for catalysis, chemical separations and sensor development. Integrating this with the ability to control the spacing of these complexes across the surface, as well as the symmetry and size of the pore structure, allows the synthetic chemist to hierarchically tailor these structured nanomaterials to specific needs. The next step up the “scale ladder” is provided by the ability to coat these mesoporous materials onto complex shapes, allowing for the intimate integration of these tailored materials into device interfaces. The ability to tailor the pore structure of these mesoporous supports is derived from the surfactant templated synthesis of mesoporous materials, an area which has seen an explosion of activity over the last decade.[1,2] The ability to decorate the surface with the desired functionality requires chemical modification of the oxide interface, most commonly achieved using organosilane self-assembly.[3-6] This manuscript describes recent results from the confluence of these two research areas, with a focus on synthetic manipulation of the morphology and chemistry of the interface, with the ultimate goal of binding metal centers in a chemically useful manner.

  1. Plasma Functionalized Nanocarbon Materials and Their Applications

    NASA Astrophysics Data System (ADS)

    Li, Yongfeng

    2015-09-01

    The plasma treatment method is important for modifying carbon nanomaterials since it has the advantage of being nonpolluting. It has the possibility of scaling up to produce large quantities necessary for commercial use. The liquid-related plasma is especially advantageous in avoiding use of toxic stabilizers and reducing agents during the nanoparticle formation process. In this work, both gas phase and liquid phase plasmas are used to modify nanocarbon materials including graphene and carbon nanotubes. The synthesis of metal nanoparticles functionalized nanocarbon materials including carbon nanotubes and graphene has been realized by an environmentally-friendly gas-liquid interfacial method. Furthermore, the new catalysts based on hybrid of nanocarbon materials and metal nanoparticles have been proved to be stable and high catalytic performance in organic molecule transformation reactions. In addition, the modification of few-layer graphene grown by chemical vapour deposition via the nitrogen plasma ion irradiation has been performed, and the modified graphene sheets as counter electrodes in bifacial dye-sensitized solar cells exhibit high performance.

  2. Computational nano-materials design of self-organized nanostructures by spinodal nano-decomposition in Eu-doped GaN

    NASA Astrophysics Data System (ADS)

    Masago, Akira; Fukushima, Tetsuya; Sato, Kazunori; Katayama-Yoshida, Hiroshi

    2016-07-01

    We propose that nanostructures spontaneously generated by spinodal decomposition can be used as an efficiently luminescent material. The doping of Eu into GaN beyond the solubility limit forms EuN nanostructures, whose forms depend on the crystal growth method and conditions. The three-dimensional crystal growth generates the Dairiseki phase constructed of EuN quantum dots. These nanostructures are suitable for emission of red light and laser. The two-dimensional layer-by-layer crystal growth leads to the Konbu phase consisting of nanorods. The Konbu phase can be applied to the bottom-up construction of distributed feedback semiconductor lasers, which is currently built by the top-down nanotechnology such as photolithography.

  3. Carbon nanotube-based functional materials for optical limiting.

    PubMed

    Chen, Yu; Lin, Ying; Liu, Ying; Doyle, James; He, Nan; Zhuang, Xiaodong; Bai, Jinrui; Blau, Werner J

    2007-01-01

    Optical limiting is an important application of nonlinear optics, useful for the protection of human eyes, optical elements, and optical sensors from intense laser pulses. An optical limiter is such a device that strongly attenuates high intensity light and potentially damaging light such as focused laser beams, whilst allowing for the high transmission of ambient light. Optical limiting properties of carbon nanotube suspensions, solubilized carbon nanotubes, small molecules doped carbon nanotubes and polymer/carbon nanotube composites have been reviewed. The optical limiting responses of carbon nanotube suspensions are shown to be dominated by nonlinear scattering as a result of thermally induced solvent-bubble formation and sublimation of the nanotubes, while the solubilized carbon nanotubes optically limit through nonlinear absorption mechanism and exhibit significant solution-concentration-dependent optical limiting responses. In the former case the optical limiting results are independent of nanotube concentrations at the same linear transmittance as that of the solubilized systems. Many efforts have been invested into the research of polymer/carbon nanotube composites in an attempt to allow for the fabrication of films required for the use of nanotubes in a real optical limiting application. The higher carbon nanotube content samples block the incident light more effectively at higher incident energy densities or intensities. The optical limiting mechanism of these composite materials is quite complicated. Besides nonlinear scattering contribution to the optical limiting, there may also be other contributions e.g., nonlinear absorption, nonlinear refraction, electronic absorption and others to the optical limiting. Further improvements in the optical limiting efficiency of the composites and in the dispersion and alignment properties of carbon nanotubes in the polymer matrix could be realized by variation of both nanostructured guest and polymer host, and by

  4. Nanostructured electrochromic smart windows: traditional materials and NIR-selective plasmonic nanocrystals

    SciTech Connect

    Runnerstrom, EL; Llordes, A; Lounis, SD; Milliron, DJ

    2014-06-04

    Electrochromic devices, which dynamically change colour under applied potential, are widely studied for use in energy-efficient smart windows. To improve the viability of smart windows, many researchers are utilizing nanomaterials, which can provide electrochromic devices with improved colouration efficiencies, faster switching times, longer cycle lives, and potentially reduced costs. In an effort to demonstrate a new type of electrochromic device that goes beyond the capabilities of commonly used electrochromic materials, researchers have turned to plasmonic transparent conductive oxide (TCO) nanocrystals. Electrochemical injection of electrons into plasmonic TCO nanocrystal films induces a shift in the plasmon frequency and gives rise to the new functionality of selective optical modulation in the near-infrared region of the solar spectrum. These nanocrystals can be used as building blocks to enable creation of advanced electrochromic devices containing mesoporous electrodes or nanocrystal-in-glass composites. Such devices have been important in advancing the field towards achieving the ideal smart window with independent control over visible and NIR transmittance.

  5. Nanostructured electrochromic smart windows: traditional materials and NIR-selective plasmonic nanocrystals.

    PubMed

    Runnerstrom, Evan L; Llordés, Anna; Lounis, Sebastien D; Milliron, Delia J

    2014-09-21

    Electrochromic devices, which dynamically change colour under applied potential, are widely studied for use in energy-efficient smart windows. To improve the viability of smart windows, many researchers are utilizing nanomaterials, which can provide electrochromic devices with improved colouration efficiencies, faster switching times, longer cycle lives, and potentially reduced costs. In an effort to demonstrate a new type of electrochromic device that goes beyond the capabilities of commonly used electrochromic materials, researchers have turned to plasmonic transparent conductive oxide (TCO) nanocrystals. Electrochemical injection of electrons into plasmonic TCO nanocrystal films induces a shift in the plasmon frequency and gives rise to the new functionality of selective optical modulation in the near-infrared region of the solar spectrum. These nanocrystals can be used as building blocks to enable creation of advanced electrochromic devices containing mesoporous electrodes or nanocrystal-in-glass composites. Such devices have been important in advancing the field towards achieving the ideal smart window with independent control over visible and NIR transmittance. PMID:24935022

  6. 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.

  7. Computer Code for Nanostructure Simulation

    NASA Technical Reports Server (NTRS)

    Filikhin, Igor; Vlahovic, Branislav

    2009-01-01

    Due to their small size, nanostructures can have stress and thermal gradients that are larger than any macroscopic analogue. These gradients can lead to specific regions that are susceptible to failure via processes such as plastic deformation by dislocation emission, chemical debonding, and interfacial alloying. A program has been developed that rigorously simulates and predicts optoelectronic properties of nanostructures of virtually any geometrical complexity and material composition. It can be used in simulations of energy level structure, wave functions, density of states of spatially configured phonon-coupled electrons, excitons in quantum dots, quantum rings, quantum ring complexes, and more. The code can be used to calculate stress distributions and thermal transport properties for a variety of nanostructures and interfaces, transport and scattering at nanoscale interfaces and surfaces under various stress states, and alloy compositional gradients. The code allows users to perform modeling of charge transport processes through quantum-dot (QD) arrays as functions of inter-dot distance, array order versus disorder, QD orientation, shape, size, and chemical composition for applications in photovoltaics and physical properties of QD-based biochemical sensors. The code can be used to study the hot exciton formation/relation dynamics in arrays of QDs of different shapes and sizes at different temperatures. It also can be used to understand the relation among the deposition parameters and inherent stresses, strain deformation, heat flow, and failure of nanostructures.

  8. Functional, Responsive Materials Assembled from Recombinant Oleosin

    NASA Astrophysics Data System (ADS)

    Hammer, Daniel

    Biological cells are surrounded by a plasma membrane made primarily of phospholipids that form a bilayer. This membrane is permselective and compartmentalizes the cell. A simple form of artificial cell is the vesicle, in which a phospholipid bilayer membrane surrounds an aqueous solution. However, there is no a priori reason why a membrane needs to be made of phospholipids. It could be made of any surfactant that forms a bilayer. We have assembled membranes and other structures from the recombinant plant protein oleosin. The ability to assemble from a recombinant protein means that every molecule is identical, we have complete control over the sequence, and hence can build in designer functionality with high fidelity, including adhesion and enzymatic activity. Such incorporation is trivial using the tools of molecular biology. We find that while many variants of oleosin make membranes, others make micelles and sheets. We show how the type of supramolecular structure can be altered by the conditions of solvent, such as ionic strength, and the architecture of the surfactant itself. We show that protease cleavable domains can be incorporated within oleosin, and be engineered to protect other functional domains such as adhesive motifs, to make responsive materials whose activity and shape depend on the action of proteases. We will also present the idea of making ``Franken''-oleosins, where large domains of native oleosin are replaced with domains from other functional proteins, to make hybrids conferred by the donor protein. Thus, we can view oleosin as a template upon which a vast array of designer functionalities can be imparted..

  9. Functional materials for energy-efficient buildings

    NASA Astrophysics Data System (ADS)

    Ebert, H.-P.

    2015-08-01

    The substantial improving of the energy efficiency is essential to meet the ambitious energy goals of the EU. About 40% of the European energy consumption belongs to the building sector. Therefore the reduction of the energy demand of the existing building stock is one of the key measures to deliver a substantial contribution to reduce CO2-emissions of our society. Buildings of the future have to be efficient in respect to energy consumption for construction and operation. Current research activities are focused on the development of functional materials with outstanding thermal and optical properties to provide, for example, slim thermally superinsulated facades, highly integrated heat storage systems or adaptive building components. In this context it is important to consider buildings as entities which fulfill energy and comfort claims as well as aesthetic aspects of a sustainable architecture.

  10. Synthesis of functional materials in combustion reactions

    NASA Astrophysics Data System (ADS)

    Zhuravlev, V. D.; Bamburov, V. G.; Ermakova, L. V.; Lobachevskaya, N. I.

    2015-12-01

    The conditions for obtaining oxide compounds in combustion reactions of nitrates of metals with organic chelating-reducing agents such as amino acids, urea, and polyvinyl alcohol are reviewed. Changing the nature of internal fuels and the reducing agent-to-oxidizing agent ratio makes possible to modify the thermal regime of the process, fractal dimensionality, morphology, and dispersion of synthesized functional materials. This method can be used to synthesize simple and complex oxides, composites, and metal powders, as well as ceramics and coatings. The possibilities of synthesis in combustion reactions are illustrated by examples of αand γ-Al2O3, YSZ composites, uranium oxides, nickel powder, NiO and NiO: YSZ composite, TiO2, and manganites, cobaltites, and aluminates of rare earth elements.

  11. Synthesis of functional materials in combustion reactions

    SciTech Connect

    Zhuravlev, V. D. Bamburov, V. G.; Ermakova, L. V.; Lobachevskaya, N. I.

    2015-12-15

    The conditions for obtaining oxide compounds in combustion reactions of nitrates of metals with organic chelating–reducing agents such as amino acids, urea, and polyvinyl alcohol are reviewed. Changing the nature of internal fuels and the reducing agent-to-oxidizing agent ratio makes possible to modify the thermal regime of the process, fractal dimensionality, morphology, and dispersion of synthesized functional materials. This method can be used to synthesize simple and complex oxides, composites, and metal powders, as well as ceramics and coatings. The possibilities of synthesis in combustion reactions are illustrated by examples of αand γ-Al{sub 2}O{sub 3}, YSZ composites, uranium oxides, nickel powder, NiO and NiO: YSZ composite, TiO{sub 2}, and manganites, cobaltites, and aluminates of rare earth elements.

  12. Improved cladding nano-structured materials with self-repairing capabilities

    SciTech Connect

    Popa-Simil, L.

    2012-07-01

    When designing nuclear reactors or the materials that go into them, one of the key challenges is finding materials that can withstand an outrageously extreme environment. In addition to constant bombardment by radiation, reactor materials may be subjected to extremes in temperature, physical stress, and corrosive conditions. A limitation in fuel burnup is and usage of the nuclear fuel material is related to the structural material radiation damage, that makes the fuel be removed with low-burnup and immobilized in the waste storage pools. The advanced burnup brings cladding material embitterment due to radiation damage effects corroborated with corrosion effects makes the fuel pellet life shorter. The novel nano-clustered structured sintered material may mitigate simultaneously the radiation damage and corrosion effects driving to more robust structural materials that may make the nuclear reactor safer and more reliable. The development of nano-clustered sinter alloys provides new avenues for further examination of the role of grain boundaries and engineered material interfaces in self-healing of radiation-induced defects driving to the design of highly radiation-tolerant materials for the next generation of nuclear energy applications. (authors)

  13. Materials design and development of functional materials for industry.

    PubMed

    Asahi, Ryoji; Morikawa, Takeshi; Hazama, Hirofumi; Matsubara, Masato

    2008-02-13

    It is now well recognized that we are witnessing a golden age of innovation with novel materials, with discoveries that are important for both basic science and industry. With the development of theory along with computing power, quantum materials design-the synthesis of materials with the desired properties in a controlled way via materials engineering on the atomic scale-is becoming a major component of materials research. Computational prediction based on first-principles calculations has helped to find an efficient way to develop materials that are much needed for industry, as we have seen in the successful development of visible-light sensitized photocatalysts and thermoelectric materials. Close collaboration between theory and experiment is emphasized as an essential for success.

  14. Zinc oxide nanostructure-modified textile and its application to biosensing, photocatalysis, and as antibacterial material.

    PubMed

    Hatamie, Amir; Khan, Azam; Golabi, Mohsen; Turner, Anthony P F; Beni, Valerio; Mak, Wing Cheung; Sadollahkhani, Azar; Alnoor, Hatim; Zargar, Behrooz; Bano, Sumaira; Nur, Omer; Willander, Magnus

    2015-10-01

    Recently, one-dimensional nanostructures with different morphologies (such as nanowires, nanorods (NRs), and nanotubes) have become the focus of intensive research, because of their unique properties with potential applications. Among them, zinc oxide (ZnO) nanomaterials has been found to be highly attractive, because of the remarkable potential for applications in many different areas such as solar cells, sensors, piezoelectric devices, photodiode devices, sun screens, antireflection coatings, and photocatalysis. Here, we present an innovative approach to create a new modified textile by direct in situ growth of vertically aligned one-dimensional (1D) ZnO NRs onto textile surfaces, which can serve with potential for biosensing, photocatalysis, and antibacterial applications. ZnO NRs were grown by using a simple aqueous chemical growth method. Results from analyses such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the ZnO NRs were dispersed over the entire surface of the textile. We have demonstrated the following applications of these multifunctional textiles: (1) as a flexible working electrode for the detection of aldicarb (ALD) pesticide, (2) as a photocatalyst for the degradation of organic molecules (i.e., Methylene Blue and Congo Red), and (3) as antibacterial agents against Escherichia coli. The ZnO-based textile exhibited excellent photocatalytic and antibacterial activities, and it showed a promising sensing response. The combination of sensing, photocatalysis, and antibacterial properties provided by the ZnO NRs brings us closer to the concept of smart textiles for wearable sensing without a deodorant and antibacterial control. Perhaps the best known of the products that is available in markets for such purposes are textiles with silver nanoparticles. Our modified textile is thus providing acceptable antibacterial properties, compared to available commercial modified textiles. PMID:26372851

  15. Zinc oxide nanostructure-modified textile and its application to biosensing, photocatalysis, and as antibacterial material.

    PubMed

    Hatamie, Amir; Khan, Azam; Golabi, Mohsen; Turner, Anthony P F; Beni, Valerio; Mak, Wing Cheung; Sadollahkhani, Azar; Alnoor, Hatim; Zargar, Behrooz; Bano, Sumaira; Nur, Omer; Willander, Magnus

    2015-10-01

    Recently, one-dimensional nanostructures with different morphologies (such as nanowires, nanorods (NRs), and nanotubes) have become the focus of intensive research, because of their unique properties with potential applications. Among them, zinc oxide (ZnO) nanomaterials has been found to be highly attractive, because of the remarkable potential for applications in many different areas such as solar cells, sensors, piezoelectric devices, photodiode devices, sun screens, antireflection coatings, and photocatalysis. Here, we present an innovative approach to create a new modified textile by direct in situ growth of vertically aligned one-dimensional (1D) ZnO NRs onto textile surfaces, which can serve with potential for biosensing, photocatalysis, and antibacterial applications. ZnO NRs were grown by using a simple aqueous chemical growth method. Results from analyses such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the ZnO NRs were dispersed over the entire surface of the textile. We have demonstrated the following applications of these multifunctional textiles: (1) as a flexible working electrode for the detection of aldicarb (ALD) pesticide, (2) as a photocatalyst for the degradation of organic molecules (i.e., Methylene Blue and Congo Red), and (3) as antibacterial agents against Escherichia coli. The ZnO-based textile exhibited excellent photocatalytic and antibacterial activities, and it showed a promising sensing response. The combination of sensing, photocatalysis, and antibacterial properties provided by the ZnO NRs brings us closer to the concept of smart textiles for wearable sensing without a deodorant and antibacterial control. Perhaps the best known of the products that is available in markets for such purposes are textiles with silver nanoparticles. Our modified textile is thus providing acceptable antibacterial properties, compared to available commercial modified textiles.

  16. Graphene oxide-SiO2 hybrid nanostructure as coating material for capillary electrochromatography.

    PubMed

    Qu, Qishu; Xuan, Han; Zhang, Kehua; Ding, Yi; Xu, Qin

    2016-05-01

    Graphene oxide (GO) has been considered as a promising stationary phase for chromatographic separation. However, the very strong adsorption of the analytes on the GO surface lead to the severe peak tailing, which in turn resulting in decreased separation performance. In this work, GO and silica nanoparticles hybrid nanostructures (GO/SiO2 NPs@column) were coated onto the capillary inner wall by passing the mixture of GO and silica sol through the capillary column. The successful of coating of GO/SiO2 NPs onto the capillary wall was confirmed by SEM and electroosmotic flow mobilities test. By partially covering the GO surface with silica nanoparticles, the peak tailing was decreased greatly while the unique high shape selectivity arises from the surface of remained GO was kept. Consequently, compared with the column modified with GO (GO@column), the column modified with GO and silica nanoparticles through layer-by-layer method (GO-SiO2 NPs@column), or the column modified with silica nanoparticles (SiO2 NPs@column), GO/SiO2 NPs@column possessed highest resolutions. The GO/SiO2 NPs@column was applied to separate egg white and both acidic and basic proteins as well as three glycoisoforms of ovalbumin were separated in a single run within 36 min. The intra-day, inter-day, and column-to-column reproducibilities were evaluated by calculating the RSDs of the retention of naphthalene and biphenyl in open-tubular capillary electrochromatography. The RSD values were found to be less than 7.1%. PMID:26829671

  17. Functional liquid-crystalline assemblies: self-organized soft materials.

    PubMed

    Kato, Takashi; Mizoshita, Norihiro; Kishimoto, Kenji

    2005-12-16

    In the 21st century, soft materials will become more important as functional materials because of their dynamic nature. Although soft materials are not as highly durable as hard materials, such as metals, ceramics, and engineering plastics, they can respond well to stimuli and the environment. The introduction of order into soft materials induces new dynamic functions. Liquid crystals are ordered soft materials consisting of self-organized molecules and can potentially be used as new functional materials for electron, ion, or molecular transporting, sensory, catalytic, optical, and bio-active materials. For this functionalization, unconventional materials design is required. Herein, we describe new approaches to the functionalization of liquid crystals and show how the design of liquid crystals formed by supramolecular assembly and nano-segregation leads to the formation of a variety of new self-organized functional materials.

  18. Patterning of light-extraction nanostructures on sapphire substrates using nanoimprint and ICP etching with different masking materials.

    PubMed

    Chen, Hao; Zhang, Qi; Chou, Stephen Y

    2015-02-27

    Sapphire nanopatterning is the key solution to GaN light emitting diode (LED) light extraction. One challenge is to etch deep nanostructures with a vertical sidewall in sapphire. Here, we report a study of the effects of two masking materials (SiO2 and Cr) and different etching recipes (the reaction gas ratio, the reaction pressure and the inductive power) in a chlorine-based (BCl3 and Cl2) inductively coupled plasma (ICP) etching of deep nanopillars in sapphire, and the etching process optimization. The masking materials were patterned by nanoimprinting. We have achieved high aspect ratio sapphire nanopillar arrays with a much steeper sidewall than the previous etching methods. We discover that the SiO2 mask has much slower erosion rate than the Cr mask under the same etching condition, leading to the deep cylinder-shaped nanopillars (122 nm diameter, 200 nm pitch, 170 nm high, flat top, and a vertical sidewall of 80° angle), rather than the pyramid-shaped shallow pillars (200 nm based diameter, 52 nm height, and 42° sidewall) resulted by using Cr mask. The processes developed are scalable to large volume LED manufacturing. PMID:25648720

  19. One-pot synthesis of interpenetrating inorganic/organic networks of CuO/resorcinol-formaldehyde aerogels: nanostructured energetic materials.

    PubMed

    Leventis, Nicholas; Chandrasekaran, Naveen; Sadekar, Anand G; Sotiriou-Leventis, Chariklia; Lu, Hongbing

    2009-04-01

    For many applications ranging from catalysis to sensors to energetic materials, it is desirable to produce intimate mixtures of nanoparticles. For instance, to improve the reaction rates of energetic materials, the oxidizing agent and the fuel need to be mixed as intimately as possible, ideally at the nanoscopic level. In this context, the acidity of a hydrated CuCl(2) solution reacting toward a network of CuO nanoparticles (a good oxidant) is used to induce one-pot cogelation of a nanostructured network of a resorcinol-formaldehyde resin (RF, the fuel). The resulting wet gels are dried to aerogels, and upon pyrolysis under Ar, the interpenetrating CuO/RF network undergoes a smelting reaction toward metallic Cu. Upon ignition in the open air, pure RF aerogels do not burn, while CuO/RF composites, even with substoichiometric CuO, sustain combustion, burning completely leaving only a solid residue of CuO whose role then has been that of a redox mediator through the smelting reaction.

  20. 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

    2016-06-01

    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. PMID:27222911

  1. 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

    2016-06-01

    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.

  2. Quantitative Nanostructure Characterization Using Atomic Pair Distribution Functions Obtained From Laboratory Electron Microscopes

    SciTech Connect

    Abeykoon M.; Billinge S.; Malliakas, C.D.; Juhas, P.; Bozin, E.S.; Kanatzidis, M.G.

    2012-05-01

    Quantitatively reliable atomic pair distribution functions (PDFs) have been obtained from nanomaterials in a straightforward way from a standard laboratory transmission electron microscope (TEM). The approach looks very promising for making electron derived PDFs (ePDFs) a routine step in the characterization of nanomaterials because of the ubiquity of such TEMs in chemistry and materials laboratories. No special attachments such as energy filters were required on the microscope. The methodology for obtaining the ePDFs is described as well as some opportunities and limitations of the method.

  3. Development of Micro and Nanostructured Materials for Interfacial Self-Healing

    ERIC Educational Resources Information Center

    Blaiszik, Benjamin James

    2009-01-01

    Damage in polymeric coatings, adhesives, microelectronic components, and composites spans many length scales. For small scale damage, autonomic self-healing can repair multiple damage modes without manual intervention. In autonomic self-healing materials, a healing response is triggered by damage to the material. Size scale considerations, such as…

  4. Nanostructured materials for inhibition of bacterial adhesion in orthopedic implants: a minireview.

    PubMed

    Montanaro, L; Campoccia, D; Arciola, C R

    2008-09-01

    Orthopedic implants may fail owing to different reasons: poor osseointegration at the tissue-implant interface, generation of wear debris, stress and strain imbalance between implant and surrounding tissues, and infections. To ensure success in orthopedics, implant materials must not evoke an undesirable inflammatory response, they must be habitable by bone-forming cells (favoring adhesion of osteoblasts), hinder formation of soft connective tissue (hindering adhesion of fibroblasts), and be anti-infective (discouraging bacterial adhesion). Recent studies have suggested that nanophase materials have a better efficacy as bone implants in favoring osseointegration compared to conventional orthopedic implant materials. This minireview discusses studies on nanophase materials as bone implants, focusing on the effect of these materials in inhibiting bacterial adhesion for the prevention of implant infections.

  5. Functional organic materials for electronics industries

    NASA Technical Reports Server (NTRS)

    Shibayama, K.; Ono, H.

    1982-01-01

    Topics closely related with organic, high molecular weight material synthesis are discussed. These are related to applications such as display, recording, sensors, semiconductors, and I.C. correlation. New materials are also discussed. General principles of individual application are not included. Materials discussed include color, electrochromic, thermal recording, organic photoconductors for electrophotography, and photochromic materials.

  6. Structure and optical function of amorphous photonic nanostructures from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species

    PubMed Central

    Saranathan, Vinodkumar; Forster, Jason D.; Noh, Heeso; Liew, Seng-Fatt; Mochrie, Simon G. J.; Cao, Hui; Dufresne, Eric R.; Prum, Richard O.

    2012-01-01

    Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy β-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the single-scattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing β-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology. PMID:22572026

  7. Reactive ballistic deposition of nanostructured model materials for electrochemical energy conversion and storage.

    PubMed

    Flaherty, David W; Hahn, Nathan T; May, R Alan; Berglund, Sean P; Lin, Yong-Mao; Stevenson, Keith J; Dohnalek, Zdenek; Kay, Bruce D; Mullins, C Buddie

    2012-03-20

    Porous, high surface area materials have critical roles in applications including catalysis, photochemistry, and energy storage. In these fields, researchers have demonstrated that the nanometer-scale structure modifies mechanical, optical, and electrical properties of the material, greatly influencing its behavior and performance. Such complex chemical systems can involve several distinct processes occurring in series or parallel. Understanding the influence of size and structure on the properties of these materials requires techniques for producing clean, simple model systems. In the fields of photoelectrochemistry and lithium storage, for example, researchers need to evaluate the effects of changing the electrode structure of a single material or producing electrodes of many different candidate materials while maintaining a distinctly favorable morphology. In this Account, we introduce our studies of the formation and characterization of high surface area, porous thin films synthesized by a process called reactive ballistic deposition (RBD). RBD is a simple method that provides control of the morphology, porosity, and surface area of thin films by manipulating the angle at which a metal-vapor flux impinges on the substrate during deposition. This approach is largely independent of the identity of the deposited material and relies upon limited surface diffusion during synthesis, which enables the formation of kinetically trapped structures. Here, we review our results for the deposition of films from a number of semiconductive materials that are important for applications such as photoelectrochemical water oxidation and lithium ion storage. The use of RBD has enabled us to systematically control individual aspects of both the structure and composition of thin film electrodes in order to probe the effects of each on the performance of the material. We have evaluated the performance of several materials for potential use in these applications and have identified

  8. Reactive ballistic deposition of nanostructured model materials for electrochemical energy conversion and storage.

    PubMed

    Flaherty, David W; Hahn, Nathan T; May, R Alan; Berglund, Sean P; Lin, Yong-Mao; Stevenson, Keith J; Dohnalek, Zdenek; Kay, Bruce D; Mullins, C Buddie

    2012-03-20

    Porous, high surface area materials have critical roles in applications including catalysis, photochemistry, and energy storage. In these fields, researchers have demonstrated that the nanometer-scale structure modifies mechanical, optical, and electrical properties of the material, greatly influencing its behavior and performance. Such complex chemical systems can involve several distinct processes occurring in series or parallel. Understanding the influence of size and structure on the properties of these materials requires techniques for producing clean, simple model systems. In the fields of photoelectrochemistry and lithium storage, for example, researchers need to evaluate the effects of changing the electrode structure of a single material or producing electrodes of many different candidate materials while maintaining a distinctly favorable morphology. In this Account, we introduce our studies of the formation and characterization of high surface area, porous thin films synthesized by a process called reactive ballistic deposition (RBD). RBD is a simple method that provides control of the morphology, porosity, and surface area of thin films by manipulating the angle at which a metal-vapor flux impinges on the substrate during deposition. This approach is largely independent of the identity of the deposited material and relies upon limited surface diffusion during synthesis, which enables the formation of kinetically trapped structures. Here, we review our results for the deposition of films from a number of semiconductive materials that are important for applications such as photoelectrochemical water oxidation and lithium ion storage. The use of RBD has enabled us to systematically control individual aspects of both the structure and composition of thin film electrodes in order to probe the effects of each on the performance of the material. We have evaluated the performance of several materials for potential use in these applications and have identified

  9. Improvement of the functional properties of nanostructured Ti-Ni shape memory alloys by means of thermomechanical processing

    NASA Astrophysics Data System (ADS)

    Kreitcberg, Alena

    Severe plastic deformation (SPD) is commonly used for nanostructure formation in Ti-Ni shape memory alloys (SMAs), but it increases the risk of damage during processing and, consequently, negatively affects functional fatigue resistance of these materials. The principal objective of this project is, therefore, to study the interrelations between the processing conditions, damageability during processing, microstructure and the functional properties of Ti-Ni SMAs with the aim of improving long-term functional performances of these materials by optimizing their processing conditions. First, microstructure and fatigue properties of Ti-Ni SMAs were studied after thermomechanical treatment (TMT) with different combinations of severe cold and warm rolling (CR and WR), as well as intermediate and post-deformation annealing (IA and PDA) technological steps. It was shown that either when WR and IA were introduced into the TMT schedule, or CR intensity was decreased, the fatigue life was improved as a consequence of less processing-induced damage and higher density of the favorable B2-austenite texture. This improvement was reached, however, at a price of a lower multi-cycle functional stability of these materials, the latter being a direct consequence of the microstructure coarsening after higher-temperature lower-intensity processing. At the end of this study, however, it was not possible to distinguish between contributions to the functional performances of Ti-Ni SMAs from different processing-related features: a) grain/subgrain size; b) texture; and c) level of rolling-induced defects. To be capable of separating contributions to the functional properties of Ti-Ni alloys from grain/subgrain size and from texture, the theoretical crystallographic resource of recovery strain after different TMTs and, therefore, different textures, were calculated and compared with the experiment. The comparative analysis showed that the structural factors (grain/subgrain size) strongly

  10. Thermoelectric transport phenomena in semiconducting nanostructures

    NASA Astrophysics Data System (ADS)

    Cornett, Jane

    The efficiencies of state-of-the-art thermoelectric devices made from bulk materials remain too low for widespread application. Early predictions by Hicks and Dresselhaus indicated that one potential route for improving the thermoelectric properties of materials was through nanostructuring. This predicted improvement was due to two effects: an increase in the thermoelectric power factor and a decrease in the lattice thermal conductivity. In this thesis, new models are developed for calculation of the thermoelectric transport properties of nanostructures. The results of these models are in line with what has been seen experimentally in the field of nanostructured thermoelectrics: the power factor of nanostructures falls below the bulk value for sizes accessible by current experimental techniques. While this is demonstrated first for a particular system (cylindrical InSb nanowires), this result is shown to hold true regardless of the dimensionality of the system, the material of interest or the temperature. Using the analytical forms of the transport properties of nanostructured systems, we derive universal scaling relations for the power factor which further point to the fundamental and general nature of this result. Calculations done for nanostructured systems in which the scattering time is a function of carrier energy indicate that the introduction of nanoscale grain boundaries can lead to improvements in the power factor. We present experimental methods for the fabrication and characterization of porous bismuth-antimony-telluride (Bi2-xSbxTe3 ) thin films using a templated deposition technique. Preliminary results from this experimental work indicate that the nanostructured morphology of the templates used for the deposition of porous films limits diffusion during grain growth, and thus the crystal structure of these porous films differs from that of films deposited on dense substrates. For fundamental investigation of the effects of porosity on thermoelectric

  11. Ferroelectric polymer nanostructures: fabrication, structural characteristics and performance under confinement.

    PubMed

    Guo, Dong; Zeng, Fei; Dkhil, Brahim

    2014-02-01

    Ferroelectric polymers have recently attracted tremendous research interest due to their potential application in various emerging flexible devices. Nanostructured ferroelectric polymer materials, such as nanorods, nanotube, and nanowires, are essential for miniaturization of the relevant electronic components. More importantly, their improved sensitivity and functionality may be used to enhance the performance of existing devices or to develop and design new devices. In this article, the recently developed methods for fabricating ferroelectric polymer nanostructures are briefly reviewed. In particular, the distinct crystallization behaviors confined at the nanometer scale, the nanoconfinement induced structural change, their influence on the physical properties of the ferroelectric polymer nanostructures, and the possible underlying mechanisms are discussed.

  12. Functional Carbon Materials for Electrochemical Energy Storage

    NASA Astrophysics Data System (ADS)

    Zhou, Huihui

    The ability to harvest and convert solar energy has been associated with the evolution of human civilization. The increasing consumption of fossil fuels since the industrial revolution, however, has brought to concerns in ecological deterioration and depletion of the fossil fuels. Facing these challenges, humankind is forced to seek for clean, sustainable and renewable energy resources, such as biofuels, hydraulic power, wind power, geothermal energy and other kinds of alternative energies. However, most alternative energy sources, generally in the form of electrical energy, could not be made available on a continuous basis. It is, therefore, essential to store such energy into chemical energy, which are portable and various applications. In this context, electrochemical energy-storage devices hold great promises towards this goal. The most common electrochemical energy-storage devices are electrochemical capacitors (ECs, also called supercapacitors) and batteries. In comparison to batteries, ECs posses high power density, high efficiency, long cycling life and low cost. ECs commonly utilize carbon as both (symmetric) or one of the electrodes (asymmetric), of which their performance is generally limited by the capacitance of the carbon electrodes. Therefore, developing better carbon materials with high energy density has been emerging as one the most essential challenges in the field. The primary objective of this dissertation is to design and synthesize functional carbon materials with high energy density at both aqueous and organic electrolyte systems. The energy density (E) of ECs are governed by E = CV 2/2, where C is the total capacitance and V is the voltage of the devices. Carbon electrodes with high capacitance and high working voltage should lead to high energy density. In the first part of this thesis, a new class of nanoporous carbons were synthesized for symmetric supercapacitors using aqueous Li2SO4 as the electrolyte. A unique precursor was adopted to

  13. Static and Dynamical Properties of Ferroelectrics and Related Materials in Bulk and Nanostructure Forms

    NASA Astrophysics Data System (ADS)

    Gui, Zhigang

    Ferroelectrics (FE) and multiferroics (MFE) have attracted a lot of attentions due to their rich and novel properties. Studies towards FE and MFE are of both fundamental and technological importance. We use a first-principles-based effective Hamiltonian method, conventional ab-initio packages and linear-scale three-dimension fragment method to investigate several important issues about FE and MFE. Tuning the properties of FE and MFE films are essential for miniaturized device applications, which can be realized through epitaxial strain and growth direction. In this dissertation, we use the effective Hamiltonian method to study (i) BaTiO3 films grown along the (110) pseudocubic direction on various substrates, (ii) BaTiO3 films grown on a single substrate along directions varying from [001] to [110] via [111] pseudocubic direction. Optimized physical responses or curie temperatures are found along some special directions or under epitaxial strain of certain range. FE and MFE nanostructures are shown to possess electrical vortices (known as one type topological defect), which have the potential to be used in new memory devices. However, the dynamic mechanism behind them is barely known. We use the effective Hamiltonian method to reveal that there exists a distinct mode which is shown to be responsible for the formation of the electrical vortices and in the THz region. Spin-canted magnetic structures are commonly seen in MFE, which results in the coexistence of two or more magnetic order parameters in the same structure. Understanding the physics behind such coupled magnetic order parameters is of obvious benefit for the sake of control of the magnetic properties of such systems. We employ both the effective Hamiltonian and ab-initio methods to derive and prove there is a universal law that explicitly correlates various magnetic order parameters with the different types of oxygen octahedra rotations. FE or MFE possessing electrical vortices are experimentally shown to

  14. Incorporation of Novel Nanostructured Materials into Solar Cells and Nanoelectronic Devices

    SciTech Connect

    Rodriguez, Rene; Pak, Joshua; Holland, Andrew; Hunt, Alan; Bitterwolf, Thomas; Qiang, You; Bergman, Leah; Berven, Christine; Punnoose, Alex; Tenne, Dmitri

    2011-11-11

    Each of the investigators on this project has had significant accomplishments toward the production of semiconductor nanoparticles, particles, and thin films and attempts to incorporate these materials into photovoltaics or sensors; to use them for improving fluorescence diagnostics; or to employ them as cancer fighting agents. The synthesis and characterization of the nanomaterials, and more recently the device construction and testing of these materials, have been the subject of several publications and presentations by team members. During the course of the investigations, several students were fully involved as part of their graduate and undergraduate training. The nature of these projects in material development dictates that the students have gained significant experience in a diverse array of material-related topics.

  15. Single potential electrodeposition of nanostructured battery materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Mosby, James Matthew

    The increasing reliance on portable electronics is continuing to fuel research in the area of low power lithium-ion batteries, while a new surge in research for high power lithium-ion batteries has been sparked by the demand for plug-in hybrid electric vehicles (PHEV) and plug-in electric vehicles (PEV). To compete with current lead-acid battery chemistry, a few of the shortcomings of lithium-ion battery chemistry need to be addressed. The three main drawbacks of lithium-ion batteries for this application are: (1) low power density, (2) safety, and (3) the high cost of manufacturing. This dissertation covers the development of a low cost fabrication technique for an alternative anode material with high surface area geometries. The anode material is safer than the conventional anode material in lithium-ion batteries and the high surface area geometries permit higher power densities to be achieved. Electrodeposition is an inexpensive alternative method for synthesizing materials for electronics, energy conversion and energy storage applications relative to traditional solid state techniques. These techniques led to expensive device fabrication. Unlike most solid state synthesis routes, electrodeposition can usually be performed from common solutions and at moderate conditions. Three other benefits of using electrodeposition are: (1) it allows precise control of composition and crystallinity, (2) it provides the ability to deposit on complex shapes, and (3) it can deposit materials with nanoscale dimensions. The use of electrodeposition for alternative anode materials results in the deposition of the material directly onto the current collector that is used for the battery testing and applications without the need of additional binders and with excellent electrical contact. While this improves the characterization of the material and lowers the weight of the non-active materials within a battery, it also allows the anode to be deposited onto current collectors with

  16. Electrophoretic forming of functionally-graded materials

    SciTech Connect

    Sarkar, P.; Datta, S.; Nicholson, P.S.

    1997-12-31

    Electrophoretic deposition (EPD) is a colloidal forming process where electrically charged particles are deposited onto an oppositely-charged electrode from an electrostatically stabilized suspension by the application of a dc electric field. It is a cheap and facile technique to fabricate complicated ceramic shapes. EPD is very effective method to synthesize ceramic/ceramic and metal/ceramic composites, eg.; dispersed, laminar, fibre reinforced, and functionally graded materials (FGM) etc. By EPD it is possible to synthesize step FGMs and continuous profile FGMs. The compositional profile of the FGM can be controlled by deposition current density, second component flow rate, suspension concentration etc. Step and continuous profile Al{sub 2}O{sub 3}/YSZ and continuous profile Al{sub 2}O{sub 3}/MoSi{sub 2}, Al{sub 2}O{sub 3}/Ni and YSZ/Ni fabrication is reported herein. The microstructures of the FGMs produced were characterized by optical/electron microscopy and micro-indentation was used to quantify the Vicker`s hardness and fracture toughness variation across The FGM sections.

  17. DOE-EFRC Center on Nanostructuring for Efficient Energy Conversion (CNEEC)

    SciTech Connect

    Prinz, Friedrich B.; Bent, Stacey F.

    2015-10-22

    CNEEC’s mission has been to understand how nanostructuring of materials can enhance efficiency for solar energy conversion to produce hydrogen fuel and to solve fundamental cross-cutting problems. The overarching hypothesis underlying CNEEC research was that controlling, synthesizing and modifying materials at the nanometer scale increases the efficiency of energy conversion and storage devices and systems. In this pursuit, we emphasized the development of functional nanostructures that are based primarily on earth abundant and inexpensive materials.

  18. PREFACE: Self-organized nanostructures

    NASA Astrophysics Data System (ADS)

    Rousset, Sylvie; Ortega, Enrique

    2006-04-01

    In order to fabricate ordered arrays of nanostructures, two different strategies might be considered. The `top-down' approach consists of pushing the limit of lithography techniques down to the nanometre scale. However, beyond 10 nm lithography techniques will inevitably face major intrinsic limitations. An alternative method for elaborating ultimate-size nanostructures is based on the reverse `bottom-up' approach, i.e. building up nanostructures (and eventually assemble them to form functional circuits) from individual atoms or molecules. Scanning probe microscopies, including scanning tunnelling microscopy (STM) invented in 1982, have made it possible to create (and visualize) individual structures atom by atom. However, such individual atomic manipulation is not suitable for industrial applications. Self-assembly or self-organization of nanostructures on solid surfaces is a bottom-up approach that allows one to fabricate and assemble nanostructure arrays in a one-step process. For applications, such as high density magnetic storage, self-assembly appears to be the simplest alternative to lithography for massive, parallel fabrication of nanostructure arrays with regular sizes and spacings. These are also necessary for investigating the physical properties of individual nanostructures by means of averaging techniques, i.e. all those using light or particle beams. The state-of-the-art and the current developments in the field of self-organization and physical properties of assembled nanostructures are reviewed in this issue of Journal of Physics: Condensed Matter. The papers have been selected from among the invited and oral presentations of the recent summer workshop held in Cargese (Corsica, France, 17-23 July 2005). All authors are world-renowned in the field. The workshop has been funded by the Marie Curie Actions: Marie Curie Conferences and Training Courses series named `NanosciencesTech' supported by the VI Framework Programme of the European Community, by

  19. Intermatrix Synthesis as a rapid, inexpensive and reproducible methodology for the in situ functionalization of nanostructured surfaces with quantum dots

    NASA Astrophysics Data System (ADS)

    Bastos-Arrieta, Julio; Muñoz, Jose; Stenbock-Fermor, Anja; Muñoz, Maria; Muraviev, Dmitri N.; Céspedes, Francisco; Tsarkova, Larisa A.; Baeza, Mireia

    2016-04-01

    Intermatrix Synthesis (IMS) technique has proven to be a valid methodology for the in situ incorporation of quantum dots (QDs) in a wide range of nanostructured surfaces for the preparation of advanced hybrid-nanomaterials. In this sense, this communication reports the recent advances in the application of IMS for the synthesis of CdS-QDs with favourable distribution on sulfonated polyetherether ketone (SPEEK) membrane thin films (TFs), multiwall carbon nanotubes (MWCNTs) and nanodiamonds (NDs). The synthetic route takes advantage of the ion exchange functionality of the reactive surfaces for the loading of the QDs precursor and consequent QDs appearance by precipitation. The benefits of such modified nanomaterials were studied using CdS-QDs@MWCNTs hybrid-nanomaterials. CdS-QDs@MWCNTs has been used as conducting filler for the preparation of electrochemical nanocomposite sensors, which present electrocatalytic properties. Finally, the optical properties of the QDs contained on MWCNTs could allow a new procedure for the analytical detection of nanostructured carbon allotropes in water.

  20. Bioinspired chemistry: Rewiring nanostructures

    NASA Astrophysics Data System (ADS)

    Ulijn, Rein V.; Caponi, Pier-Francesco

    2010-07-01

    The cell's dynamic skeleton, a tightly regulated network of protein fibres, continues to provide inspiration for the design of synthetic nanostructures. Genetic engineering has now been used to encode non-biological functionality within these structures.

  1. A practical approach to calculate the time evolutions of magnetic field effects on photochemical reactions in nano-structured materials.

    PubMed

    Yago, Tomoaki; Wakasa, Masanobu

    2015-04-21

    A practical method to calculate time evolutions of magnetic field effects (MFEs) on photochemical reactions involving radical pairs is developed on the basis of the theory of the chemically induced dynamic spin polarization proposed by Pedersen and Freed. In theory, the stochastic Liouville equation (SLE), including the spin Hamiltonian, diffusion motions of the radical pair, chemical reactions, and spin relaxations, is solved by using the Laplace and the inverse Laplace transformation technique. In our practical approach, time evolutions of the MFEs are successfully calculated by applying the Miller-Guy method instead of the final value theorem to the inverse Laplace transformation process. Especially, the SLE calculations are completed in a short time when the radical pair dynamics can be described by the chemical kinetics consisting of diffusions, reactions and spin relaxations. The SLE analysis with a short calculation time enables one to examine the various parameter sets for fitting the experimental date. Our study demonstrates that simultaneous fitting of the time evolution of the MFE and of the magnetic field dependence of the MFE provides valuable information on the diffusion motions of the radical pairs in nano-structured materials such as micelles where the lifetimes of radical pairs are longer than hundreds of nano-seconds and the magnetic field dependence of the spin relaxations play a major role for the generation of the MFE.

  2. Fabrication of Smart Chemical Sensors Based on Transition-Doped-Semiconductor Nanostructure Materials with µ-Chips

    PubMed Central

    Rahman, Mohammed M.; Khan, Sher Bahadar; Asiri, Abdullah M.

    2014-01-01

    Transition metal doped semiconductor nanostructure materials (Sb2O3 doped ZnO microflowers, MFs) are deposited onto tiny µ-chip (surface area, ∼0.02217 cm2) to fabricate a smart chemical sensor for toxic ethanol in phosphate buffer solution (0.1 M PBS). The fabricated chemi-sensor is also exhibited higher sensitivity, large-dynamic concentration ranges, long-term stability, and improved electrochemical performances towards ethanol. The calibration plot is linear (r2 = 0.9989) over the large ethanol concentration ranges (0.17 mM to 0.85 M). The sensitivity and detection limit is ∼5.845 µAcm−2mM−1 and ∼0.11±0.02 mM (signal-to-noise ratio, at a SNR of 3) respectively. Here, doped MFs are prepared by a wet-chemical process using reducing agents in alkaline medium, which characterized by UV/vis., FT-IR, Raman, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM) etc. The fabricated ethanol chemical sensor using Sb2O3-ZnO MFs is simple, reliable, low-sample volume (<70.0 µL), easy of integration, high sensitivity, and excellent stability for the fabrication of efficient I–V sensors on μ-chips. PMID:24454785

  3. Nano-structural analysis of effective transport paths in fuel-cell catalyst layers by using stochastic material network methods

    NASA Astrophysics Data System (ADS)

    Shin, Seungho; Kim, Ah-Reum; Um, Sukkee

    2016-02-01

    A two-dimensional material network model has been developed to visualize the nano-structures of fuel-cell catalysts and to search for effective transport paths for the optimal performance of fuel cells in randomly-disordered composite catalysts. Stochastic random modeling based on the Monte Carlo method is developed using random number generation processes over a catalyst layer domain at a 95% confidence level. After the post-determination process of the effective connectivity, particularly for mass transport, the effective catalyst utilization factors are introduced to determine the extent of catalyst utilization in the fuel cells. The results show that the superficial pore volume fractions of 600 trials approximate a normal distribution curve with a mean of 0.5. In contrast, the estimated volume fraction of effectively inter-connected void clusters ranges from 0.097 to 0.420, which is much smaller than the superficial porosity of 0.5 before the percolation process. Furthermore, the effective catalyst utilization factor is determined to be linearly proportional to the effective porosity. More importantly, this study reveals that the average catalyst utilization is less affected by the variations of the catalyst's particle size and the absolute catalyst loading at a fixed volume fraction of void spaces.

  4. Fabrication of smart chemical sensors based on transition-doped-semiconductor nanostructure materials with µ-chips.

    PubMed

    Rahman, Mohammed M; Khan, Sher Bahadar; Asiri, Abdullah M

    2014-01-01

    Transition metal doped semiconductor nanostructure materials (Sb2O3 doped ZnO microflowers, MFs) are deposited onto tiny µ-chip (surface area, ∼0.02217 cm(2)) to fabricate a smart chemical sensor for toxic ethanol in phosphate buffer solution (0.1 M PBS). The fabricated chemi-sensor is also exhibited higher sensitivity, large-dynamic concentration ranges, long-term stability, and improved electrochemical performances towards ethanol. The calibration plot is linear (r(2) = 0.9989) over the large ethanol concentration ranges (0.17 mM to 0.85 M). The sensitivity and detection limit is ∼5.845 µAcm(-2)mM(-1) and ∼0.11±0.02 mM (signal-to-noise ratio, at a SNR of 3) respectively. Here, doped MFs are prepared by a wet-chemical process using reducing agents in alkaline medium, which characterized by UV/vis., FT-IR, Raman, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM) etc. The fabricated ethanol chemical sensor using Sb2O3-ZnO MFs is simple, reliable, low-sample volume (<70.0 µL), easy of integration, high sensitivity, and excellent stability for the fabrication of efficient I-V sensors on μ-chips.

  5. 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.

  6. Super-Resolution Molecular and Functional Imaging of Nanoscale Architectures in Life and Materials Science

    PubMed Central

    Habuchi, Satoshi

    2014-01-01

    Super-resolution (SR) fluorescence microscopy has been revolutionizing the way in which we investigate the structures, dynamics, and functions of a wide range of nanoscale systems. In this review, I describe the current state of various SR fluorescence microscopy techniques along with the latest developments of fluorophores and labeling for the SR microscopy. I discuss the applications of SR microscopy in the fields of life science and materials science with a special emphasis on quantitative molecular imaging and nanoscale functional imaging. These studies open new opportunities for unraveling the physical, chemical, and optical properties of a wide range of nanoscale architectures together with their nanostructures and will enable the development of new (bio-)nanotechnology. PMID:25152893

  7. Nano-structured phosphorus composite as high-capacity anode materials for lithium batteries.

    PubMed

    Wang, Li; He, Xiangming; Li, Jianjun; Sun, Wenting; Gao, Jian; Guo, Jianwei; Jiang, Changyin

    2012-09-01

    More than LiP service: The adsorption of red phosphorus into porous carbon provides a composite anode material for lithium-ion batteries. The amorphous nano phosphorus, in the carbon matrix, shows highly reversible lithium storage with high coulombic efficiencies and stable cycling capacity of 750 mAh per gram composite.

  8. A facile route for 3D aerogels from nanostructured 1D and 2D materials

    PubMed Central

    Jung, Sung Mi; Jung, Hyun Young; Dresselhaus, Mildred S.; Jung, Yung Joon; Kong, Jing

    2012-01-01

    Aerogels have numerous applications due to their high surface area and low densities. However, creating aerogels from a large variety of materials has remained an outstanding challenge. Here, we report a new methodology to enable aerogel production with a wide range of materials. The method is based on the assembly of anisotropic nano-objects (one-dimensional (1D) nanotubes, nanowires, or two-dimensional (2D) nanosheets) into a cross-linking network from their colloidal suspensions at the transition from the semi-dilute to the isotropic concentrated regime. The resultant aerogels have highly porous and ultrafine three-dimensional (3D) networks consisting of 1D (Ag, Si, MnO2, single-walled carbon nanotubes (SWNTs)) and 2D materials (MoS2, graphene, h-BN) with high surface areas, low densities, and high electrical conductivities. This method opens up a facile route for aerogel production with a wide variety of materials and tremendous opportunities for bio-scaffold, energy storage, thermoelectric, catalysis, and hydrogen storage applications. PMID:23152940

  9. A facile route for 3D aerogels from nanostructured 1D and 2D materials.

    PubMed

    Jung, Sung Mi; Jung, Hyun Young; Dresselhaus, Mildred S; Jung, Yung Joon; Kong, Jing

    2012-01-01

    Aerogels have numerous applications due to their high surface area and low densities. However, creating aerogels from a large variety of materials has remained an outstanding challenge. Here, we report a new methodology to enable aerogel production with a wide range of materials. The method is based on the assembly of anisotropic nano-objects (one-dimensional (1D) nanotubes, nanowires, or two-dimensional (2D) nanosheets) into a cross-linking network from their colloidal suspensions at the transition from the semi-dilute to the isotropic concentrated regime. The resultant aerogels have highly porous and ultrafine three-dimensional (3D) networks consisting of 1D (Ag, Si, MnO(2), single-walled carbon nanotubes (SWNTs)) and 2D materials (MoS(2), graphene, h-BN) with high surface areas, low densities, and high electrical conductivities. This method opens up a facile route for aerogel production with a wide variety of materials and tremendous opportunities for bio-scaffold, energy storage, thermoelectric, catalysis, and hydrogen storage applications.

  10. Simulating functional magnetic materials on supercomputers.

    PubMed

    Gruner, Markus Ernst; Entel, Peter

    2009-07-22

    The recent passing of the petaflop per second landmark by the Roadrunner project at the Los Alamos National Laboratory marks a preliminary peak of an impressive world-wide development in the high-performance scientific computing sector. Also, purely academic state-of-the-art supercomputers such as the IBM Blue Gene/P at Forschungszentrum Jülich allow us nowadays to investigate large systems of the order of 10(3) spin polarized transition metal atoms by means of density functional theory. Three applications will be presented where large-scale ab initio calculations contribute to the understanding of key properties emerging from a close interrelation between structure and magnetism. The first two examples discuss the size dependent evolution of equilibrium structural motifs in elementary iron and binary Fe-Pt and Co-Pt transition metal nanoparticles, which are currently discussed as promising candidates for ultra-high-density magnetic data storage media. However, the preference for multiply twinned morphologies at smaller cluster sizes counteracts the formation of a single-crystalline L1(0) phase, which alone provides the required hard magnetic properties. The third application is concerned with the magnetic shape memory effect in the Ni-Mn-Ga Heusler alloy, which is a technologically relevant candidate for magnetomechanical actuators and sensors. In this material strains of up to 10% can be induced by external magnetic fields due to the field induced shifting of martensitic twin boundaries, requiring an extremely high mobility of the martensitic twin boundaries, but also the selection of the appropriate martensitic structure from the rich phase diagram.

  11. 1D nanostructured Na7V4(P2O7)4(PO4) as high-potential and superior-performance cathode material for sodium-ion batteries.

    PubMed

    Deng, Chao; Zhang, Sen

    2014-06-25

    Tailoring materials into nanostructure offers unprecedented opportunities in the utilization of their functional properties. High-purity Na7V4(P2O7)4(PO4) with 1D nanostructure is prepared as a cathode material for rechargeable Na-ion batteries. An efficient synthetic approach is developed by carefully controlling the crystal growth in the molten sodium phosphate. Based on the XRD, XPS, TG, and morphological characterization, a molten-salt assisted mechanism for nanoarchitecture formation is revealed. The prepared Na7V4(P2O7)4(PO4) nanorod has rectangle sides and preferential [001] growth orientation. GITT evaluation indicates that the sodium de/intercalation of Na7V4(P2O7)4(PO4) nanorod involves V(3+)/V(4+) redox reaction and Na5V(3.5+)4(P2O7)4(PO4) as intermediate phase, which results in two pairs of potential plateaus at the equilibrium potentials of 3.8713 V (V(3+)/V(3.5+)) and 3.8879 V (V(3.5+)/V(4+)), respectively. The unique nanoarchitecture of the phase-pure Na7V4(P2O7)4(PO4) facilitates its reversible sodium de/intercalation, which is beneficial to the high-rate capability and the cycling stability. The Na7V4(P2O7)4(PO4) cathode delivers 80% of the capacity (obtained at C/20) at the 10 C rate and 95% of the initial capacity after 200 cycles. Therefore, it is feasible to design and fabricate an advanced rechargeable sodium-ion battery by employment of 1D nanostructured Na7V4(P2O7)4(PO4) as the cathode material.

  12. Single potential electrodeposition of nanostructured battery materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Mosby, James Matthew

    The increasing reliance on portable electronics is continuing to fuel research in the area of low power lithium-ion batteries, while a new surge in research for high power lithium-ion batteries has been sparked by the demand for plug-in hybrid electric vehicles (PHEV) and plug-in electric vehicles (PEV). To compete with current lead-acid battery chemistry, a few of the shortcomings of lithium-ion battery chemistry need to be addressed. The three main drawbacks of lithium-ion batteries for this application are: (1) low power density, (2) safety, and (3) the high cost of manufacturing. This dissertation covers the development of a low cost fabrication technique for an alternative anode material with high surface area geometries. The anode material is safer than the conventional anode material in lithium-ion batteries and the high surface area geometries permit higher power densities to be achieved. Electrodeposition is an inexpensive alternative method for synthesizing materials for electronics, energy conversion and energy storage applications relative to traditional solid state techniques. These techniques led to expensive device fabrication. Unlike most solid state synthesis routes, electrodeposition can usually be performed from common solutions and at moderate conditions. Three other benefits of using electrodeposition are: (1) it allows precise control of composition and crystallinity, (2) it provides the ability to deposit on complex shapes, and (3) it can deposit materials with nanoscale dimensions. The use of electrodeposition for alternative anode materials results in the deposition of the material directly onto the current collector that is used for the battery testing and applications without the need of additional binders and with excellent electrical contact. While this improves the characterization of the material and lowers the weight of the non-active materials within a battery, it also allows the anode to be deposited onto current collectors with

  13. Controllable Synthesis of Functional Hollow Carbon Nanostructures with Dopamine As Precursor for Supercapacitors.

    PubMed

    Liu, Chao; Wang, Jing; Li, Jiansheng; Luo, Rui; Shen, Jinyou; Sun, Xiuyun; Han, Weiqing; Wang, Lianjun

    2015-08-26

    N-doped hollow carbon spheres (N-HCSs) are promising candidates as electrode material for supercapacitor application. In this work, we report a facile one-step synthesis of discrete and highly dispersible N-HCSs with dopamine (DA) as a carbon precursor and TEOS as a structure-assistant agent in a mixture containing water, ethanol, and ammonia. The architectures of resultant N-HCSs, including yolk-shell hollow carbon spheres (YS-HCSs), single-shell hollow carbon spheres (SS-HCSs), and double-shells hollow carbon spheres (DS-HCSs), can be efficiently controlled through the adjustment of the amount of ammonia. To explain the relation and formation mechanism of these hollow carbon structures, the samples during the different synthetic steps, including polymer/silica spheres, carbon/silica spheres and silica spheres by combustion in air, were characterized by TEM. Electrochemical measurements performed on YS-HCSs, SS-HCSs, and DS-HCSs showed high capacitance with 215, 280, and 381 F g(-1), respectively. Moreover, all the nitrogen-doped hollow carbon nanospheres showed a good cycling stability 97.0% capacitive retention after 3000 cycles. Notably, the highest capacitance of DS-HCSs up to 381 F g(-1) is higher than the capacitance reported so far for many carbon-based materials, which may be attributed to the high surface area, hollow structure, nitrogen functionalization, and double-shell architecture. These kinds of N-doped hollow-structured carbon spheres may show promising prospects as advanced energy storage materials and catalyst supports.

  14. Controllable Synthesis of Functional Hollow Carbon Nanostructures with Dopamine As Precursor for Supercapacitors.

    PubMed

    Liu, Chao; Wang, Jing; Li, Jiansheng; Luo, Rui; Shen, Jinyou; Sun, Xiuyun; Han, Weiqing; Wang, Lianjun

    2015-08-26

    N-doped hollow carbon spheres (N-HCSs) are promising candidates as electrode material for supercapacitor application. In this work, we report a facile one-step synthesis of discrete and highly dispersible N-HCSs with dopamine (DA) as a carbon precursor and TEOS as a structure-assistant agent in a mixture containing water, ethanol, and ammonia. The architectures of resultant N-HCSs, including yolk-shell hollow carbon spheres (YS-HCSs), single-shell hollow carbon spheres (SS-HCSs), and double-shells hollow carbon spheres (DS-HCSs), can be efficiently controlled through the adjustment of the amount of ammonia. To explain the relation and formation mechanism of these hollow carbon structures, the samples during the different synthetic steps, including polymer/silica spheres, carbon/silica spheres and silica spheres by combustion in air, were characterized by TEM. Electrochemical measurements performed on YS-HCSs, SS-HCSs, and DS-HCSs showed high capacitance with 215, 280, and 381 F g(-1), respectively. Moreover, all the nitrogen-doped hollow carbon nanospheres showed a good cycling stability 97.0% capacitive retention after 3000 cycles. Notably, the highest capacitance of DS-HCSs up to 381 F g(-1) is higher than the capacitance reported so far for many carbon-based materials, which may be attributed to the high surface area, hollow structure, nitrogen functionalization, and double-shell architecture. These kinds of N-doped hollow-structured carbon spheres may show promising prospects as advanced energy storage materials and catalyst supports. PMID:26243663

  15. Biomimetic micro∕nanostructured functional surfaces for microfluidic and tissue engineering applications

    PubMed Central

    Stratakis, E.; Ranella, A.; Fotakis, C.

    2011-01-01

    This paper reviews our work on the application of ultrafast pulsed laser micro∕nanoprocessing for the three-dimensional (3D) biomimetic modification of materials surfaces. It is shown that the artificial surfaces obtained by femtosecond-laser processing of Si in reactive gas atmosphere exhibit roughness at both micro- and nanoscales that mimics the hierarchical morphology of natural surfaces. Along with the spatial control of the topology, defining surface chemistry provides materials exhibiting notable wetting characteristics which are potentially useful for open microfluidic applications. Depending on the functional coating deposited on the laser patterned 3D structures, we can achieve artificial surfaces that are (a) of extremely low surface energy, thus water-repellent and self-cleaned, and (b) responsive, i.e., showing the ability to change their surface energy in response to different external stimuli such as light, electric field, and pH. Moreover, the behavior of different kinds of cells cultured on laser engineered substrates of various wettabilities was investigated. Experiments showed that it is possible to preferentially tune cell adhesion and growth through choosing proper combinations of surface topography and chemistry. It is concluded that the laser textured 3D micro∕nano-Si surfaces with controllability of roughness ratio and surface chemistry can advantageously serve as a novel means to elucidate the 3D cell-scaffold interactions for tissue engineering applications. PMID:21522501

  16. Repairable, nanostructured biomimetic hydrogels

    NASA Astrophysics Data System (ADS)

    Firestone, M.; Brombosz, S.; Grubjesic, S.

    2013-03-01

    Proteins facilitate many key cellular processes, including signal recognition and energy transduction. The ability to harness this evolutionarily-optimized functionality could lead to the development of protein-based systems useful for advancing alternative energy storage and conversion. The future of protein-based, however, requires the development of materials that will stabilize, order and control the activity of the proteins. Recently we have developed a synthetic approach for the preparation of a durable biomimetic chemical hydrogel that can be reversibly swollen in water. The matrix has proven ideal for the stable encapsulation of both water- and membrane-soluble proteins. The material is composed of an aqueous dispersion of a diacrylate end-derivatized PEO-PPO-PEO macromer, a saturated phospholipid and a zwitterionic co-surfactant that self-assembles into a nanostructured physical gel at room temperature as determined by X-ray scattering. The addition of a water soluble PEGDA co-monomer and photoinitator does not alter the self-assembled structure and UV irradiation serves to crosslink the acrylate end groups on the macromer with the PEGDA forming a network within the aqueous domains as determined by FT-IR. More recently we have begun to incorporate reversible crosslinks employing Diels-Alder chemistry, allowing for the extraction and replacement of inactive proteins. The ability to replenish the materials with active, non-denatured forms of protein is an important step in advancing these materials for use in nanostructured devices This work was supported by the Office of Basic Energy Sciences, Division of Materials Sciences, USDoE under Contract No. DE-AC02-06CH11357.

  17. Local decomposition of solid solutions, nanostructures and optical materials with negative refractive index

    NASA Astrophysics Data System (ADS)

    Ishchuk, Valeriy M.; Sobolev, Vladimir

    2016-03-01

    In this paper, a possibility of use of the controlled decomposition of solid solutions of oxides with perovskite structure in the state of coexisting domains of the antiferroelectric (AFE) and ferroelectric (FE) phases for manufacturing materials with the negative refractive index is demonstrated. The lead zirconate titanate-based solid solutions are considered as an example of substances suitable for creation of such materials. Manufactured composites constitute a dielectric AFE matrix with a structure of conducting interphase boundaries separating domains of the FE and AFE phases. The electric conductivity of the interphase boundaries occurs as a result of the local decomposition of the solid solutions in the vicinity of these boundaries. The decomposition process and consequently the conductivity of the interphase boundaries can be controlled by means of external influences.

  18. Laser-induced deposition of nanostructured copper microwires on surfaces of composite materials

    NASA Astrophysics Data System (ADS)

    Tumkin, Ilia I.; Panov, Maxim S.; Shishkova, Ekaterina V.; Bal'makov, Michail D.

    2015-05-01

    Microelectronics industry is growing fast and the rate of new devices' development increases every year. Therefore, methods for simple and high-precision metal coating on dielectrics are needed. Existing methods do not allow performing the high-precision metal deposition without using photomasks, while making photomask for each prototype is long and expensive process. One of the methods of maskless metal deposition is laser-induced chemical liquid-phase deposition (LCLD). In this work we show the effect of substrate surface type on a result of LCLD. Deposited copper structures were characterized by SEM, EDX and impedance spectroscopy. The results show that laser-induced copper deposition is highly affected by the surface being homogeneous or composite material. It was found that the deposits with low resistivity and high quality metal localization mostly appear on the two-phase surfaces. In contrast, deposits on one-phase surfaces exhibited poor topology of copper material.

  19. Alternative nano-structured thin-film materials used as durable thermal nanoimprint lithography templates.

    PubMed

    Bossard, M; Boussey, J; Le Drogoff, B; Chaker, M

    2016-02-19

    Nanoimprint templates made of diamond-like carbon (DLC) and amorphous silicon carbide (SiC) thin films and fluorine-doped associated materials, i.e. F-DLC and F-SiC were investigated in the context of thermal nanoimprint lithography (NIL) with respect to their release properties. Their performances in terms of durability and stability were evaluated and compared to those of conventional silicon or silica molds coated with antisticking molecules applied as a self-assembled monolayer. Plasma-enhanced chemical vapor deposition parameters were firstly tuned to optimize mechanical and structural properties of the DLC and SiC thin films. The impact of the amount of fluorine dopant on the deposited thin films properties was then analyzed. A comparative analysis of DLC, F-DLC as well as SiC and F-SiC molds was then carried out over multiple imprints, performed into poly (methyl methacrylate) (PMMA) thermo-plastic resist. The release properties of un-patterned films were evaluated by the measurement of demolding energies and surface energies, associated with a systematic analysis of the mold surface contamination. These analyses showed that the developed materials behave as intrinsically easy-demolding and contamination-free molds over series of up to 40 imprints. To our knowledge, it is the first time that such a large number of imprints has been considered within an exhaustive comparative study of materials for NIL. Finally, the developed materials went through standard e-beam lithography and plasma etching processes to obtain nanoscale-patterned templates. The replicas of those patterned molds, imprinted into PMMA, were shown to be of high fidelity and good stability after several imprints. PMID:26783068

  20. Alternative nano-structured thin-film materials used as durable thermal nanoimprint lithography templates

    NASA Astrophysics Data System (ADS)

    Bossard, M.; Boussey, J.; Le Drogoff, B.; Chaker, M.

    2016-02-01

    Nanoimprint templates made of diamond-like carbon (DLC) and amorphous silicon carbide (SiC) thin films and fluorine-doped associated materials, i.e. F-DLC and F-SiC were investigated in the context of thermal nanoimprint lithography (NIL) with respect to their release properties. Their performances in terms of durability and stability were evaluated and compared to those of conventional silicon or silica molds coated with antisticking molecules applied as a self-assembled monolayer. Plasma-enhanced chemical vapor deposition parameters were firstly tuned to optimize mechanical and structural properties of the DLC and SiC thin films. The impact of the amount of fluorine dopant on the deposited thin films properties was then analyzed. A comparative analysis of DLC, F-DLC as well as SiC and F-SiC molds was then carried out over multiple imprints, performed into poly (methyl methacrylate) (PMMA) thermo-plastic resist. The release properties of un-patterned films were evaluated by the measurement of demolding energies and surface energies, associated with a systematic analysis of the mold surface contamination. These analyses showed that the developed materials behave as intrinsically easy-demolding and contamination-free molds over series of up to 40 imprints. To our knowledge, it is the first time that such a large number of imprints has been considered within an exhaustive comparative study of materials for NIL. Finally, the developed materials went through standard e-beam lithography and plasma etching processes to obtain nanoscale-patterned templates. The replicas of those patterned molds, imprinted into PMMA, were shown to be of high fidelity and good stability after several imprints.

  1. Functionalized graphene as a nanostructured membrane for removal of copper and mercury from aqueous solution: a molecular dynamics simulation study.

    PubMed

    Azamat, Jafar; Khataee, Alireza; Joo, Sang Woo

    2014-09-01

    The purpose of the present study was to investigate the removal of copper and mercury using functionalized graphene as a nanostructured membrane. The molecular dynamics simulation method was used to investigate the removal ability of these ions from aqueous solution using functionalized graphene membrane. The studied systems included a functionalized graphene membrane which was placed in the aqueous ionic solution of CuCl2 and HgCl2. An external electrical field was applied along the z axis of the system. The results indicated that the application of electrical field on the system caused the desired ions to pass through the functionalized graphene membrane. The Fluorinated pore (F-pore) terminated graphene selectively conducted Cu(2+) and Hg(2+) ions. The calculation of the potential of mean force of ions revealed that Cu(2+) and Hg(2+) ions face a relatively small energy barrier and could not pass through the F-pore graphene unless an external electrical field was applied upon them. In contrast, the energy barrier for the Cl(-) ion was large and it could not pass through the F-pore graphene. The findings of the study indicate that the permeation of ions across the graphene was a function of applied electrical fields. The findings of the present study are based on the detailed analysis and consideration of potential of mean force and radial distribution function curves.

  2. Synthesis of nanostructured hybrid sorbent materials using organosilane self-assembly on mesoporous ceramic oxides

    SciTech Connect

    Fryxell, Glen E.

    2007-01-30

    The single most important factor in determining quality of life in human society is the availability of pure, clean drinking water. Wars have been fought, and will continue to be fought, over access and control of clean water. Drinking water has two major classes of contamination, biological contamination and chemical contamination. Bacterial contamination can be dealt with by a number of well-established technologies (e.g. chlorination, ozone, UV, etc.), but chemical contamination is a somewhat more challenging target. Common organic contaminants, such as pesticides, agricultural chemicals, industrial solvents, and fuels can be removed by treatment with UV/ozone, activated carbon or plasma technologies. Toxic heavy metals like mercury, lead and cadmium can be partially addressed by using traditional sorbent materials like alumina, but these materials bind metal ions non-specifically and can easily be saturated with harmless, ubiquitous species like calcium, magnesium and zinc (which are actually nutrients, and don’t need to be removed). Another weakness of these traditional sorbent materials is that metal ion sorption to a ceramic oxide surface is a reversible process, meaning they can easily desorb back into the drinking water supply.

  3. Impact ignition of aluminum-teflon based energetic materials impregnated with nano-structured carbon additives

    NASA Astrophysics Data System (ADS)

    Kappagantula, Keerti; Pantoya, Michelle L.; Hunt, Emily M.

    2012-07-01

    The inclusion of graphene into composite energetic materials to enhance their performance is a new area of interest. Studies have shown that the addition of graphene significantly enhances the thermal transport properties of an energetic composite, but how graphene influences the composite's ignition sensitivity has not been studied. The objective of this study is to examine the influence of carbon additives in composite energetic material composed of aluminum and polytetrafluoroethylene (Teflon™) on ignition sensitivity due to low velocity, drop weight impact. Specifically, three forms of carbon additives were investigated and selected based on different physical and structural properties: spherically shaped amorphous nano particles of carbon, cylindrically shaped multi walled carbon nanotubes, and sheet like graphene flakes. Results show an interesting trend: composites consisting of carbon nanotubes are significantly more sensitive to impact ignition and require the lowest ignition energy. In contrast, graphene is least sensitive to ignition exhibiting negligible reduction in ignition energy with low concentrations of graphene additive. While graphene does not significantly sensitize the energetic composite to ignition, graphene does, however, result in greater overall reactivity as observed through images of the reaction. The enhanced thermal transport properties of graphene containing composites may promote greater energy transport once ignited, but those properties do not also increase ignition sensitivity. These results and the understanding of the structural arrangement of particles within a composite as a key parameter affecting impact ignition sensitivity will have an impact on the safe handling and use of composite energetic materials.

  4. Functional Nanofibers via Electospinning: New Materials and Processes

    NASA Astrophysics Data System (ADS)

    Manasco, Joshua Lee

    Cyclodextrins are fascinating, amphiphilic molecules that are of considerable interest due to their ability to be used in a variety of applications ranging from pharmaceuticals and cosmetics to foods and agriculture. These are ring-shaped sugar molecules possess a hydrophobic cavity and a hydrophilic exterior which imparts them water solubility. There are three main types of naturally occurring cyclodextrins namely alpha-, beta- and gamma- CD which have 6, 7 and 8 member rings, respectively. Owing to their hydrophobic interior, cyclodextrin molecules encapsulate hydrophobic guest molecules (from small to macromolecules) to form host-guest supermolecular structures. Chemically modified CDs are often preferred to the natural forms, particularly methylated (MbetaCD) and hydroxypropylated (HPbetaCD) cyclodextrins, for their enhanced solubility and chemical stability. Electrostatic spinning (electrospinning) of nanofibers has drawn significant research attention in recent decades. This technique involves the stretching of a polymer solution or melt in a high electric field to produce fibers on the nanoscale. These 1-Dimensional nanostructures possess extraordinary surface-to-weight ratio and find applications that vary from filtration membranes and tissue scaffolding materials to drug delivery and many others. The scope of this research attempts to leverage the unique features of CDs with the high aspect ratio of nanofibers to create functional nanomaterials. The present study can be divided into three sections. In the first part, we establish that CDs can be electrospun without the need for a "carrier" polymer. This discovery may serve to extend the horizon of what is currently considered "electrospinnable" from macromolecules now to small molecules. The ability to electrospin CDs led to their incorporation of other polymers to create bicomponent fibers with poly (vinyl alcohol) (PVA) and polyacrylonitrile (PAN). In the case of PVA we demonstrate the ability to not

  5. Kinetic trapping - a strategy for directing the self-assembly of unique functional nanostructures.

    PubMed

    Yan, Yun; Huang, Jianbin; Tang, Ben Zhong

    2016-10-14

    Supramolecular self-assembly into various nano- or microscopic structures based on non-covalent interactions between molecules has been recognized as a very efficient approach that leads to functional materials. Since most non-covalent interactions are relatively weak and form and break without significant activation barriers, the thermodynamic equilibrium of many supramolecular systems can be easily influenced by processing pathways that allow the system to stay in a kinetically trapped state. Thus far, kinetic traps have been found to be very important in producing more elaborate structural and functional diversity of self-assembled systems. In this review, we try to summarize the approaches that can produce kinetically trapped self-assemblies based on examples made by us. We focus on the following subjects: (1) supramolecular pathway dependent self-assembly, including kinetically trapped self-assemblies facilitated by host-guest chemistry, coordination chemistry, and electrostatic interactions; (2) physical processing pathway dependent self-assembly, including solvent quality controlled self-assembly, evaporation induced self-assembly and crystallization induced self-assembly.

  6. Density functional theory in materials science

    PubMed Central

    Neugebauer, Jörg; Hickel, Tilmann

    2013-01-01

    Materials science is a highly interdisciplinary field. It is devoted to the understanding of the relationship between (a) fundamental physical and chemical properties governing processes at the atomistic scale with (b) typically macroscopic properties required of materials in engineering applications. For many materials, this relationship is not only determined by chemical composition, but strongly governed by microstructure. The latter is a consequence of carefully selected process conditions (e.g., mechanical forming and annealing in metallurgy or epitaxial growth in semiconductor technology). A key task of computational materials science is to unravel the often hidden composition–structure–property relationships using computational techniques. The present paper does not aim to give a complete review of all aspects of materials science. Rather, we will present the key concepts underlying the computation of selected material properties and discuss the major classes of materials to which they are applied. Specifically, our focus will be on methods used to describe single or polycrystalline bulk materials of semiconductor, metal or ceramic form. PMID:24563665